Simpósio Brasileiro de Sistemas Elétricos - SBSE

Performance dos modelos do solo com parâmetros elétricos variáveis com a frequência e o teor de umidade

Walter Luiz Manzi de Azevedo — 2022-11-30

This article investigates the performance of three soil models with electrical parameters dependent on the frequency and the moisture content proposed by Smith-Longmire, Scott, and Messier. Firstly, the grounding harmonic impedance is calculated for these soil models using the electromagnetic software FEKO for a frequency range between 100 Hz and 5 MHz. Three different cases are analyzed: homogeneous soil and stratified soils (2 and 3 layers). Then, the ground potential rise (GPR) is computed for two typical lightning impulse currents. All results are compared with those computed assuming a soil model with frequency-constant electrical parameters. Results show a variation in grounding harmonic impedances for the different soil models, being the most expressive for the Smith-Longmire model. The GPR presents a significant reduction in the peak values obtained, especially for the frequency-dependent homogeneous soil. However, there is a small impact on the potential elevation for soil with 3 layers due to the lowest equivalent resistivity, concerning a soil computed with the same soil topology using the frequency-constant parameters.

Análise de SRF-PLL e DSOGI-PLL Aplicados em um VSC Quatro Fios Conectado à Rede Elétrica com Desequilíbrio de Tensão

Alex F. Silva — 2022-11-30

The three-phase four-wire VSCs voltage source converters are used to connect sustainable sources to the distribution system where the loads are predominantly single-phase. The three-phase distribution system with unbalanced neutral has unwanted negative and zero sequence components. In this condition the synchronism between the VSC and the electrical grid that is done using the PLL (Phase Locked Loop) is affected. SRF-PLL (Synchronous Reference Frame-PLL) is popularly used, however it does not perform well in unbalanced systems. DSOGI- PLL (Dual Second Order Generalized Integrator-PLL) ensures synchronism between the VSC and the unbalanced power grid. Thus, the purpose of this article is to evaluate the effect of imbalance in ac currents of the VSC using the SRF-PLL and DSOGI-PLL

Estudo Inicial a Respeito de Sobretensões em Linhas de Transmissão Considerando o Efeito da Frequência Sobre os Parâmetros do Solo

Tainá Fernanda Garbelim Pascoalato — 2022-11-30

In order to compute the electromagnetic transients in power systems adequately, several papers in the literature have proposed different approaches to properly model the ground by its frequency-dependent (FD) soil parameters (conductivity and permittivity). This article presents a brief study on how to simulate electromagnetic transients generated on single- phase transmission line (TL) subjected to slow- and fast-front disturbances. For this analysis, a summary of 8 FD soil models developed in the literature, discussing their conditions and variations, is presented. Then, the formulations of each model are included in the calculation of the longitudinal impedance and the transversal admittance of a certain TL where the impact of the FD soil models are discussed. A comparison between the transient responses obtained with a TL located above a ground considering its frequency-constant electrical parameters with those computed with different FD soil models is carried out. Results indicate that a significant modification on the transient responses characterized by reduced peaks and shifted waveforms is obtained when the FD soil models are considered for the analysis.

Análise dos Perfis de Tensão e Fator de Potência utilizando SINAPgrid para o campus da Universidade Federal do Acre

Gabriel M. Guilherme — 2022-11-30

The main objective of power electric systems is to provide the necessary energy at a satisfactory quality level. Power networks undergo various alterations through time, and as such its characteristics change along with it when compared to their early states. When dealing with distribution networks, it is important to reassure that those modifications do not harm the network’s voltage level, which can lead to an increase in technical energy losses. In this context, this paper attempts to emulate the power network belonging to the Rio Branco campus of Federal University of Acre, simulating its power flow with the help of a software called SINAPgrid. The adopted methodology involves the use of Geographic referenced coordinates for each power pole belonging to the campus distribution system. The representation of each component that compose the system were made taking into account real characteristics observed on the equipment, such as nominal values for the transformers and measurements recorded with a load analyzer in different locations throughout the university, as to obtain a real reference for the average power factor verified. All the done procedures to use the SINAPgrid software and execute the simulations, testing different scenarios with varying degrees of demand from the transformers, is described along with two possible actions to be taken and their respective outcomes, as to try to improve the voltage and power factor levels in the case studied.

Analysis of Predictive Direct Torque Control Applied to Induction Motor by Finite Element Method

A. S. Lunardi — 2022-11-30

This paper focuses on how to make the electromagnetic analyses of an induction motor drive. The induction motor is controlled by a predictive direct torque controller. Using the predictive control which by a cost-function determines the voltage vector among eight switching states from voltage source converter (VSC), making it suitable for the requirements to control the motor. The controller handles the stator flux and the electromagnetic torque with a quiet implementation and pretty adjusts. Regarding the electromagnetic analyses, it will be done by finite element features. The proposed technique will be illustrated by the results, which will provide how the electromagnetic effects occur inside the electrical machine. The conclusion with all the results is that the controller and machine can be operated with no core saturation.

Análise sobre às tecnicas aplicadas à estimação de parâmetros de sistemas de transmissão

Ronaldo F. R. Pereira — 2022-11-30

This paper shows an Extended Kalman filter-based method to estimate the parameters of transmission lines. Unlike common-place practices, in which parameters are estimated by using Least Squares methods or linear methods, the Extended Kalman filter algorithm is used. We represent the transmission line by using a steady-state model in which the voltage and current phasors are considered complex values in the d - q domain. Thereafter, it is analyzed the estimation performance of the filter-based estimator by means of a numerical simulation, considering a medium-length transmission line, and compared to other well-established methods based on two different Least Mean Square Setups. The results show that the filter is highly efficient and encourage further researches on estimation methods with optimal initialization terms. In addition, results show that the filter-based estimation method could be used jointly in phasor measurement devices for improved monitoring and control capabilities of electrical systems by estimating phasors and parameters.

Avaliações de Desempenho de um Sistema Fotovoltaico Monofásico sob Condições de Sombreamento Parcial Baseadas em Otimizações no MPPT P&O

André Luiz de Oliveira Nunes — 2022-11-30

Despite the advantages as a renewable source, photovoltaic generators still have low efficiency in converting light into electricity. Furthermore, they are sensitive to variations in solar irradiance and temperature. When weather conditions are unfavorable, the greatest impact is on electricity generation, which can be significantly reduced. In order to maximize the performance of PV system, MPPT techniques have been developed. However, when a PV system is installed in places where external agents shade the photovoltaic modules, the conventional MPPT algorithms are drastically undermined. In this context, the present work aims to evaluate two optimization methods applied to a MPPT algorithm. Supported by PSIM software, algorithms are developed and a 300 Wp single-phase PV system grid- connected is presented. Simulation results demonstrate benefits and drawbacks related to the influence of optimization on the overall efficiency of this PV system.

Otimização por Enxame de Partículas Aplicada à Alocação Ótima de TCSC em Linhas de Transmissão Congestionadas

Glaucus R. S. Lima — 2022-11-30

The power flow dynamics resulting from transmission lines charging has the potential to create nomadic congestion points, resulting in a power distribution that does not meet the requirements of economic optimality. In this context, the allocation of Thyristor Controlled Series Compensator (TCSC) plays a key role in mitigating these congestions. However, the number of possible options for allocating the compensator in a large porter system apresents a large-scale combinatorial problem. This study seeks to investigate the strategic allocation of TCSC in congested transmission lines through the application of a metaheuristic PSO (Particle Swarm Otimization), so that the Security Constrained Optimal Power Flow (FPORS) is guaranteed both in normal operation conditions and in simple network contingencies. Tests performed on the IEEE-30 and IEEE-300 systems demonstrate the effectiveness of the proposed approach.

Support Vector Machines no suporte à detecção de faltas de alta impedância. Caso base: LT 500 kV Xingu / Tucuruí

Vittorio T. Missagia1 — 2022-11-30

The equipments of an electrical system is subject to several types of failures, especially those present in the transmission that are built in an unsheltered way, thus being exposed to bad weather, which invariably results in wear and, therefore, equipment failure. Of these, transmission lines (LT) are the most susceptible to failure, due to their large extensions. From this feature in particular, the construction of LT in dense tropical forest regions has led to the occurrence of high impedance faults (FAI), which are difficult to identify by current protection systems. In this sense, identifying this phenomenon quickly before it evolves to more severe short circuits are essential, protecting equipment, reducing operation and maintenance costs, protecting the environment from possible fires and reducing the energy consequences of transmission outages. Therefore, getting the LT 500 kV Xingu / Tucuruí as an example, this work aims to analyze and propose a strategy for identifying FAI based on the use of supervised learning classifiers of the Support Vector Machines type.

Análise de Rampas de Geração Fotovoltaica de Grande Escala

Paulo H. Cunha — 2022-11-30

The search for energetic alternatives became more intense due to strong and historical drought in Brazil in the last few years. This incident can be found around the world and it is associate with climate changes, which starting to be face with hard policies of emission decrease until 2050. As consequence, the renewable energy sources has an fundamental role in the grid descarbonization. In Brazil, the places with the biggest solar irradiance are located in Northeast region. However, the growth of a sources with intermittent nature can be cause implications in the operation of interconnected grid. So, in this paper is performed an assessment considering the amount, geographic location and capacity of photovoltaic power plants already installed, as well as the planned for the next years, with the goal of estimate the possible additional requirements on the grid operation due to occurrence of photovoltaic ramps generation. As case study, it is considered the state of Piau´i, which presents the highest growth rate of amount of photovoltaic power plants.

Experimental Investigation of High Impedance Faults in MV Overhead Distribution Networks due to Mango Tree Branches

A. P. Leão — 2022-11-30

The high impedance fault (HIF) has as one of its main characteristics the low magnitude of the current produced, causing its detection and location to be impaired for the equipment currently used to protect electrical power systems, which favors the driver remain energized, increasing the likelihood of fires and the risk of death for living beings. Records of HIF characteristics in trees are a gap in the literature, making it difficult to develop new algorithms and identification methods. This study presents details of the voltage and current characteristics of HIF shunt in Mango tree branches, the result of experimental tests carried out in a laboratory designed and assembled for simulation of HIF in aerial distribution networks, aiming to obtain data for future modeling HIF shunts on trees. These oscillographs were captured using a commercial protection relay.

Minimização de multas pagas por concessionárias de distribuição de energia elétrica através da otimização dos intervalos de manutenção

Bruno A. S. Costa — 2022-11-30

This paper proposes a methodology for vegetation management in overhead distribution networks that reduces costs related to tree trimming and penalties due to transgression in targets for SAIDI (System Average Interruption Duration Index). Another objective of this paper is to compare Surrogate Models, based on Lognormal and Pearson distributions, with the Monte Carlo Method (MCM) to estimate the SAIDI probability distribution. In addition, penalties were estimated considering voltage restrictions and circuit loading limits during load transfers. The multi-criterial Particle Swarm Optimization algorithm was used to calculate the vegetation pruning intervals. The tests carried out on the RBTS bus 4 system showed that the distribution utilities costs have more reductions when the optimization process is based on the estimated penalty than on the expected value for SAIDI. In addition, the use of substitute models, to obtain the SAIDI probability distribution, presented low computational cost and good accuracy in relation to the MCM.

Análise Comparativa de Técnicas de Controle Direto de Torque e Controle Preditivo de Torque Aplicadas em Tração Elétrica

Thiago Baldim dos Santos — 2022-11-30

This paper compares three direct control strategies por induction machines, analizing it’s performance for electric vehicle tration. The stretegies analysed are DTC, DTC with PI controllers and PTC, driving an induction motor with a mechanical dinamic model of a vehicle as the load. Simulation shows that all controllers as suitable to use in EV traction, but the modulation results in better current THD and torque/flux ripple. Between the classic DTC and the PTC, the predictive controller is a better choice, with smaller THD and torque/flux ripple.

Avaliação do Impacto da Robustez na Estimação de Fluxo Magnético para os Controles Preditivos de Torque e Corrente

Thiago Baldim dos Santos — 2022-11-30

This paper analyzes the impact of using the Gopinath observer on the robustness of current and torque model predictive controls for three-phase squirrel-cage induction motors. The performance of the two controllers are compared using a magnetic flux estimator based on the voltage model and the Gopinath’s observer through simulations for the dynamic behavior of the machine when errors are introduced in its resistance values.

Planejamento do sistema de transmissão utilizando algoritmo genético e Unit Commitment

Karina Mosqueira Valente — 2022-11-30

Influências de Gerações Eólicas Interfaceadas por Inversores na Operação das Funções de Proteção Direcionais e de Seleção de Fase

Moisés J. B. B. Davi — 2022-11-30

This paper analyzes the impacts of Inverter-Interfaced Wind Power Plants (IIWPP), namely Full-Converter Generators and Doubly-Fed Induction Generators, on directional and phase-selection protection functions employed in commercial relays. For the studies, a system with a typical topology used to connect IIWPP to the grid was modeled in MATLAB- Simulink software, and contingency scenarios varying the fault type, resistance, and location were simulated. The obtained results reveal several IIWPP operational particularities which impact the directional and phase-selection protection functions.

Desenvolvimento de um controlador baseado em realimentação de estados utilizando estimadores de ordem reduzida para geração distribuída

Yasmine Neves Maia — 2022-11-30

This paper presents a distributed generation system using a power static converter connected to mains through an LCL filter. The control law is based on state feedback. The system is modelled in synchronous reference allowing the use of integral actions for eliminating state-steady errors for active and reactive powers and DC voltage controls. The feedback gains are calculated using the Linear Quadratic Regulator methodology and starting from Bryson’s rule a procedure to tune the control gains are shown based on the dynamic response of the system. Besides that, a reduced-order observer is included to reduce the required number of sensors in the output filter. Simulation results are presented to verify the control law and the estimated states in this work.

Técnica de Rastreamento de Máxima Potência Baseada em Sistemas Fotovoltaicos Aplicada ao Aquecimento por Indução

Diego Gnoatto — 2022-11-30

Considering the increasing use of induction heating, this study sought to adapt a maximum power point tracking technique already used in photovoltaic systems to deliver the best efficiency to the load, even in situations where the characteristics or parameters change. In conjunction with the tracking algorithm, the variable capacitor technique was implemented, which activates an auxiliary switch by varying the capacitance value keeping the system in resonance. To obtain the results, the system was tested with fixed capacitance values and with the action of the algorithm. In response, the system behaved satisfactorily, validating the hypothesis of better heating performance when submitted to the tracking algorithm.

Distribuição de Recursos Energéticos para Análise dos Impactos da Geração Distribuída

Alvaro R. Albertini — 2022-11-30

The increasing penetration of Distributed Energy Resources (DERs) and Distributed Generation (DG) means a paradigm change in planning and operation of power systems around the world. In order to understand and circumvent the possible challenges arising from the growing energy injection at this grid level, new modeling and analysis tools are required. This paper presents a methodology for the distribution of energy resources for power system analysis. In this method, the feeder is divided into regions and probabilities of DG occurrence are determined for each of the delimited zones. The energy resources are allocated in a random and iterative fashion, according to the established application goals, described through boundary conditions. In terms of results, the method presented the capability to estimate the occurence of load shifting, losses reduction, and changes on voltage fluctuations once the integration of DER increases. The procedure proved to be flexible and efficient in the development of case study scenarios and it may be applied, among others, in the analysis of DER penetration impacts’, hosting capacity studies.

Setting of Distance Relays on Lines Considering Weather Conditions from IEEE Standard 738

Diogo A. do Nascimento — 2022-11-30

The distance relay is responsible for ensuring the protection and reliability of an electrical system. Some failures may occur due to inaccuracies in the relay setting whether line parameters are not computed in their entirety. Usually, the literature does not discuss the influence of weather conditions on cable temperature, which may change the impedance of a line. Therefore, this work aims to evaluate how electrical current, ambient temperature, wind speed and direction, and line azimuth angle directly affect distance relay adjustment. The modeling has been performed in Simulink, comparing the results with a relay without the proper correction. The results figure out possible errors in the operation and unwanted trips.

Desenvolvimento de um Protótipo de Sistema de Geração Eólica Utilizando DFIG e Estudo de Análises Transitórias

André Lage Almeida Dias — 2022-11-30

The main advantage of using the Doubly-fed Induction Generator - DFIG, in wind power generation systems with variable speed, is that the power electronics used correspond only to a fraction of the generator’s nominal power, considering that only the slip power it is processed by the static converter connected to the rotor circuit. This paper covers details from the steps of mathematical modeling of the converters and design of the controllers, to the characterization of the prototype commissioned to carry out the study. Experimental results obtained in a 10kW DFIG are shown, and transient analyzes under different conditions preceding the stator connection with the electrical grid are discussed to validate the effectiveness of the control strategies used. Such conditions involve the parallelism with differences between the voltage amplitudes of the grid and the stator, and the parallelism with speed different from the synchronous one.

Sistema de Potência com Central Geradora Fotovoltaica: Análise de Estabilidade a Pequenas Perturbações e Projeto de Controle

Gisllane S. de Oliveira — 2022-11-30

In this paper the dynamic performance of an Eletric Power System (EPS) under several levels of penetration of Utility-scale Solar Photovoltaic generation is discussed. Furthermore, control strategies are proposed, based on the optimization of performance indexes and pole placement control, which can mitigate the impact of UFV on the damping of the system electromechanical oscillations.

Prestação de Serviços Ancilares Através de Geração Distribuída em Sistemas de Distribuição de Energia Elétrica

Rafael Messias T. Lessa Jr. — 2022-11-30

In this work, the use of Distributed Generation (DG) in Eletrical Energy Distribution Systems (SDEEs) to provide ancillary services (SAs) of active power reserve for frequency control and reactive power support for voltage control, and assist the substation in providing power to meet the demands of the loads and system losses, was analyzed. In this context, a model of remuneration of the DG units was elaborated, based on their price offers to supply the SAs mentioned above and the demands of the loads, in which the Electric Energy Distribution Concessionaire (CDEE) is the only buyer. This model differs from the strategies adopted in the Brazilian Electric System (SEB), in which SAs are provided through electricity transmission networks and their remuneration is based on charges determined by the National Electric Energy Agency (ANEEL). The simulations were performed using the A Mathematical Programming Language (AMPL) software, using the Interior Point Optimizer (IPOPT) solver. The SDEE employed in these simulations was the modified 37-node radial distribution test system from the Institute of Electrical and Electronic Engineers (IEEE). From the results obtained, the reduction in total costs between the system without DG units and with these generators was 41.53%. Furthermore, active and reactive power losses decreased by around 98.31% and 97.3%, respectively. These values suggest the possible benefits that DG and their remuneration based on a competitive market can promote to SEB, to CDEE and, consequently, to the final consumers of electricity.

Análise do Comportamento Térmico de um Transformador de Potência Através do Uso de Sensoriamento por Fibras Ópticas

L. H. Medeiros — 2022-11-30

Power transformers are essential equipments for the proper functioning of the electrical power system. Therefore, there is a need to provide solutions that extend their useful life and monitoring methods to avoid failures and consequently losses to electrical companies. This work presents a series of tests carried out in a prototype transformer built specifically for the purpose of studying the internal thermal behavior, using optical fibers to obtain the direct measurement of the winding temperatures. Thus, analysis of thermal phenomena that occur under different operating conditions are presented, discussing these phenomena from the perspective of temperature rise and loss of life, aiming to reconcile theory with the actual behavior of a transformer, suggesting adequate operating conditions, and also serving as a basis for future thermal studies in power transformers.

Análise Comparativa entre Controles Digitais Aplicados a Acionamento de Motor de Indução Trifásico Alimentado por Sistema Fotovoltaico de Estágio Duplo

Gabriel C. Baldissera — 2022-11-30

This article proposes the use of different digital control techniques for three-phase inverters that drive three-phase induction motors. A DC to DC boost converter, powered by photovoltaic (PV) panels, supplies the inverter via a DC bus. The system also has batteries connected to the DC bus through a bidirectional converter, which are intended to supply the demand of the electric motor, when this is greater than the power of PV generation. Both DC converters are controlled in order to provide maximum power to the load and keep the DC bus voltage controlled.

Estudo de Mitigação de Harmônicos com a Otimização de Filtros Passivos Existentes - Estudo de Caso

Wiverton Nunes Silva — 2022-11-30

In accordance with the advancement of technology and the necessity to make the production process more competitive and within an adequate margin cost, It’s been coming some requirements in industry that are speed variations in production process. Thus, frequency converters/inverters appear as a solution to equalize this problem, however the application of frequency converters in old industrial plants brings some inconveniences such as: increased harmonics in the system, reduced power factor and reduced voltage level on a permanent basis. Industrial plants usually already have a system to filter harmonics and correct the power factor of the installation at the coupling point (PAC), however it is necessary to reassess the system and propose some action to extend the useful life and application of the existing filter, thus reducing the mitigation costs. In this study, a real case of filtering system rearrangement and power factor correction of an installation will be presented.

Desenvolvimento de um algoritmo computacional baseado em grafos para síntese de conversores cc-cc

André Luiz Silva Crivellari — 2022-11-30

In this paper, a computational algorithm made in the MATLAB MathWorks (2016) program for the synthesis of cc-cc converters is proposed. From the union of converter derivation works and determination of the voltage and current values of the elements involved, a set of converters is obtained that correspond the designer’s specifications, such as static gain, number of switches, galvanic isolation and if the input current and output is not pulsed.

Estimativa do custo de implantação de um sistema trifásico a dois fios para repotencialização de redes rurais monofásicas

Leyla Kräulich — 2022-11-30

Most rural electrical loads are Single Wire Earth return (SWER), mainly for budgetary reasons. However, many rural consumers do not have their needs fully met due to the SWER limited supply capacity and its and the inability to connect three-phase motors.. The solution planned to benefit these rural properties is through the repowering of the three-phase network. The present work sought to compare distribution network projects from an economic perspective, the Three-Phase Two-Wire System (T2F) and the Conventional Three-Phase System, pointing out the most profitable solution. All structures were selected according to the rules and procedures of rural aerial distribution networks, counted for one kilometer and extended up to twenty kilometers for comparison purposes. It was found that from five kilometers of network extension, the costs with T2F will be more advantageous in relation to the three-phase.

Estimativa da Magnitude das Tensões em Sistemas Elétricos de Potência via Redes Neurais Artificiais

A. Bonini Neto — 2022-11-30

Loading margin evaluation is one of the essential tasks of power system voltage stability analysis. Conventional methods for loading margin calculation are based on continuation power flow techniques. Recently, there is growing interested to apply artificial neural network (ANN) techniques to rapidly predict the loading margin. However, traditional ANN learning algorithms usually suffer from excessive training or tuning burden and unsatisfactory generalization performance. In this work, an ANN to estimate the voltage magnitude is presented, as well as all P-V curves of electrical power systems with reduced training time. From the results, ANN presented good performance, with a mean square error in training below the specified value. Of the samples that were not part of the training, the network managed to estimate 100% of the values of the magnitude of the voltage within the established range, with residues around 10-4 and a percentage of correctness between the desired and obtained output of 99.6%.

Análise de Estações de Recarga Rápida de Veículos Elétricos como Compensadores Dinâmicos de Reativos

Bruno P. Cancian — 2022-11-30

Due to the increasing number of electric vehicles (EVs) and the need for faster charging, EVs fast charging stations (FCSs) has been spreading throughout the electric grid and can cause technical impacts in the electric distribution system due to the power withdraw of up to 350 kW. With that in mind, this paper assesses the FCSs capacity to regulate voltage through local dynamic reactive power compensation. The impacts caused by the operation of FCSs as dynamic reactive power compensators (DRPCs) are studied in a real electric distribution grid with time-series power flow (OpenDSS) together with Python routines. Additionally, the Monte Carlo method is used to model the FCSs load curve and its locations stochastically. At the end of this work, it was found that the operation of FCSs as DRPCs can improve voltage profiles and the power factor at the substation, while reduce technical energy losses.

Segurança Cibernética em Microrredes: Estado de Arte e Desafios

Bruno O. Zarpellon — 2022-11-30

The evolution that the world's electric grids have gone through in recent years (becoming intelligent) brings several advantages, such as reduced electric losses, optimization of their operation, greater integration of distributed generations, among others. However, when becoming intelligent networks, electrical networks become extremely dependent on information and communication systems with higher resilient and trustworthy standards. This feature makes the grid vulnerable to cyber-attacks of the most varied types. This bibliographical review proposes to expose some of these possible threats to smart grids, with a particular focus on the so-called microgrids, as well as their characteristics, defense mechanisms and attack detection and possible failure recovery modes.

Veículos elétricos conectados a Smart Grids: os desafios do fluxo bidirecional de cargas (V2G)

Amaro Krob — 2022-11-30

The increase in sales of electric vehicles (EV) it´s creating a new and great challenge for the planning of expansion and operation of electric energy distribution systems in Brazil. The new energy demand for charging vehicular batteries will also enable the bidirectional power flow from the Vehicle to Grid (V2G), which when properly approved by the regulatory authorities will result in an opportunity to improve the quality and cost of energy for all. This work presents the state of the art regarding the charging of electric vehicles and the main aspects related to the standardization of chargers in national and international markets. In addition, it carries out an analysis with recommendations that expand the discussions around the regulation of the sector, allowing the full potential of the bidirectional power flow to be used in the distribution grid.

Construção De Reator De Plasma Frio Para Aplicações De Filmes Finos

G. A. Cirino — 2022-11-30

It is about the construction of a sputtering system, through the use of a cold plasma reactor, for the deposition of metallic thin films. Basically, this system works by ejecting atoms of a material (target) by the bombardment of argon ions. This process takes place through the ionization of argon gas, which has its ions accelerated towards the target and when they collide with the material, ejection occurs, and these separate atoms are deposited on the substrate, forming a thin film of this material. The process for applying thin metallic films through sputtering is used in several areas, as is the case of use in industries, for beautifying and coating parts, food packaging, jewelry, photovoltaic applications and research. The construction of the system was achieved through components found on the market, taken from other electronic equipment, vacuum system and machined parts. The use of this experience can be applied in several areas, being the object of study for this case, to characterize the deposition equipment through the relation between thickness of the deposited thin film and deposition time.

Modelo Regressivo e Inteligência Artificial para Previsão de Carga no Longo Prazo: Um Estudo de Caso

Bruno K. Hammerschmitt — 2022-11-30

The load forecasting for an electrical system is the basis for expansion projections in generation, transmission and distribution sectors, and also for planning, operation and control. The errors minimization of load forecasting is brought with the reduction of costs and improvement of the general performance of the sectors involved, in such a way as to guarantee the quality of the services provided by the system, and to keep the operation safe and reliable. In this sense, the proposed study consists on carrying out the load forecasting of the Brazil’s southern subsystem using three regression models (neutral, optimistic and pessimistic), evaluating the performance of each model considering their trend curve and deviations (maximum and minimum) compared with load data samples. In addition, the load forecasting will be performed from a Multi-Layer Perceptron (MLP) artificial neural network considering the same load data, in order to evaluate the accuracy of the model. Afterwards, the regression model which presents the best performance will be combined with the MLP, extending the forecasting the future load with a long-term horizon, based on the current conjuncture of the Brazilian electricity sector.

O Problema da Acessibilidade e o Furto de Energia Elétrica

A C Zambroni de Souza — 2022-11-30

Electric energy has become essential in society's daily life and, in order to better meet everyone's needs, it is essential to address relevant problems such as the accessibility of electricity and theft of energy from the Brazilian electricity system. In this article, electric energy was studied in a holistic way as a good that can be traded and as a fundamental right for the population to live with dignity. The importance of energy for a country's development in relation to its economy and social issues. The reasons that lead to the lack of accessibility and theft of electricity in society are discussed. As the authors suggest measures to mitigate the theft of electricity and future more specific studies for each of the factors that lead the population to resort to clandestine electrical connections.

Programação de Manutenção em Redes Elétricas Preservando a Segurança Operativa

Leonardo Gonzaga da Silva — 2022-11-30

The maintenance of electrical network equipment becomes important to preserve their lifespan and should be carried out without compromising power system operation reliability. The agents that own transmission equipment deal with the maintenance scheduling problem having as priority the minimization of costs related to logistics and forced outages. They have to submit their maintenance requests to the independent system operator, who is responsible for analyzing them and establishing an integrated maintenance schedule. This is done by performing operation planning studies that seek safe and reliable operating scenarios in which network equipment are out of service for maintenance. This work presents a methodology for scheduling the maintenance of electrical transmission network equipment, with the objective of preserving system operation security as much as possible. Test results obtained for a benchmark test system illustrate the effectiveness of the proposed approach.

Análise probabilística do impacto da recarga simultânea de veículos elétricos em uma rede de distribuição europeia de baixa tensão

Nelson Rodrigues Silva — 2022-11-30

The exponential growth of electric vehicles (EVs) over the years leads to research to analyze and assess the impacts due to the simultaneous recharge of these vehicles in the electric power system (SEP). EVs are significant single-phase loads, which when added to the predominant residential load can symbolize a big problem, as the low voltage networks and their devices were not dimensioned aiming at such an increase in demand. In addition to overload and undervoltage, the sudden connection and disconnection of these devices can generate transient impacts. This work proposes a probabilistic methodology to evaluate the impacts caused by the simultaneous recharge of EVs in the SEP, aiming at future projections, while evaluating the use of distributed photovoltaic generation and grid-connected batteries as a solution. In the simulations, the uncertainties regarding the parameters (location, profiles, generation/storage capacity, among others) will be considered. Monte Carlo (MC) simulations are used in all scenarios, aiming to obtain a probabilistic assessment of the impacts on energy quality, and verifying the impacts and efficiency of the scenario proposed as a solution. The analyzes and tests will be carried out in OpenDSS software, using a European low voltage IEEE network. All results will be presented and discussed.

Trends in using hydrogen for large-scale green energy storage

Jefferson D. F. Pereira — 2022-11-30

An increasing supply of energy from renewable sources is expected soon, demanding more energy storage alternatives in the short and long-term. The short-term deals with short duration ranging from instantaneous operation (load generation balance) to satisfactory daily and weekly load curve. In the long-term, the stored energy comes from seasonal periods of excess generation that can extend over considerable time intervals. When considering the interconnection of large-scale electrical systems, the volume of surplus energy can reach hundreds of GW. The use of this surplus energy to generate hydrogen appears as a great opportunity to store clean energy, contributing to the efficient exploitation of the installed renewable capacity and contributing to the system’s decarbonization. On the other hand, areas with little economic interest or isolated areas with good potential for renewable energy are becoming attractive to produce the so-called green hydrogen, contributing to an important step towards establishing a green economy. This paper presents a brief review and discussion of expectations regarding hydrogen as an alternative for large-scale energy storage.

Desafios na implantação de linhas de transmissão aéreas, subaquáticas e subterrâneas

R. T.M MANSUR — 2022-11-30

This paper presents the feasibility studies and solutions to implement a transmission line with overhead, underwater and underground sections, addressing the challenges and engineering solutions to meet the minimum requirements required both by regulatory bodies and by the engineering areas of the agent of transmission, considering a minimum horizon of 30 years of operation, whose premise is the performance of the system with the mitigation of the probability of serious failures.

Análise das Medidas de Proteção em Redes de Média Tensão de Parques Eólicos frente Descargas Atmosféricas

João G. Lopes Jr. — 2022-11-30

Wind power generation in the national scenario has been growing in the last decades, reaching a promising position among the renewable energy generation sources. Among the possible configurations for the topology of a wind farm electrical system, air insulated installations are a consolidated and cost- effective alternative. In this context, in installations where natural or additional shielding is not common, since in many cases wind farms are installed in geographically remote locations, the concern with atmospheric discharges that can strike the medium voltage overhead networks and cause damage to equipment in the installation, such as the power transformer, becomes imperative. The purpose of the present study was to evaluate the proposition of a mitigating measure to increase the operational safety of the wind farm substation equipment. For the evaluation, simulations were performed using the ATPDraw software, with parameters defined for the lightning discharge and reference values for the electrical equipment. The results showed that the mitigating measures applied to the medium voltage overhead network decreased the voltage experienced by the power transformer, increasing its calculated safety margin in relation to its basic insulation level (BIL).

The Impact of Transmission Line and Grounding System Modeling on Special Lightning Protection Systems

Jaimis S. L. Colqui — 2022-11-30

This paper aims to assesses the performance of different models of transmission lines and grounding systems when using the underbuilt-wire protection technique against lightning overvoltages. Moreover, the frequency dependence of the soil parameters is also investigated. A first stroke representative waveform of lightning current is considered and the simulations took place in the Alternative Transients Program (ATP). It was found that simplified models of transmission lines and grounding systems that consider constant frequency electrical ground parameters result in inaccurate responses of overvoltages in the insulator strings. According to the results, depending on the case, maximum differences of 20.23% can be found.

Caracterização e Aplicações de Microrredes de Missão Crítica

Fabricio P. Moraes — 2022-11-30

The insertion of renewable sources in the electric power system (SEP) is in vogue, with the objective of meeting the demand for electric energy, mitigating environmental pollutants and achieving socioeconomic benefits. brought a new concept of electrical systems, the microgrids. A microgrid consists of the integration of distributed energy resources and loads, and can behave as a single controllable unit, being able to operate in the modes connected to the conventional grid or isolated from it. Mission-critical microgrids present themselves as an opportunity to add resilience and reliability to critical processes, that is, processes that are characterized by strict requirements for energy continuity, achieving a strategic connotation for different civil and military sectors. In this context, this article presents a review of the concepts, classifications, modes of operation and management of a microgrid with emphasis on critical microgrids. In addition, it presents typical cases focused on this application, including the conceptual scope of the power circuit and management logic of a microgrid under implementation in a Brazilian Launch Center, with an installed capacity of 3.125 MW of distributed generation.

Fault Detection in Power Systems with Synchronized Phasor Measurements and Machine Learning

Pedro Henrique Peres Morais Lopes — 2022-11-30

This paper proposes a solution for fault detection in power systems using machine learning algorithms, namely Random Forest and Support Vector Machines. A Phasor Mea- surment Unit (PMU) network is emulated in the IEEE 39-Bus New England Power System, and several fault types are simulated, including three-phase to ground, two-phase, two-phase to ground and single-phase to ground as well as line and load contingencies. The magnitude and phase of voltage and current, alongside with frequency, are measured from each PMU, and used as input to the machine learning models. Two scenarios were contemplated in this work, the first with a network of 14 PMUs, and the second with half that number, in order to verify the robustness of the aforementioned methods in relation to the number of PMUs present in the system. A Feature Importance analysis is also made, via Permutation Feature Importance, indicating which features contributed the most to the classification task at hand. Both algorithms reached a performance of around 93% accuracy and 0.94 F1-Score and the feature analysis method seems to be suitable for systemic visibility analysis. Future works are also discussed in this paper, briefly elaborating on the possibilities and immediate impacts of the addition of a feature engineering stage in this problem and on the application of the used algorithms on problems such as fault identification and location.

Uma nova abordagem para correção de erros grosseiros em estimação de estados utilizando algoritmo genético

Jeanderson Soares Mingorança — 2022-11-30

This paper presents a new methodology for correcting gross errors in power distri- bution systems state estimation (SE). A SE algorithm is developed based on the Weighted Least Squares (WLS) using a hybrid approach in which non-synchronized measurements and PMUs (Phasor Measurement Units) are used together. At the end of the process, the Normalized Residuals (NRs) are calculated for each measurement and the existence of gross errors is detected based on statistical analysis of the NRs. Suspicious measurements are identified by the highest values of NRs. A calibration factor is associated with each suspected measurement to estimate the system state and correct the gross errors. In order to determine the exact values of the calibration factors, a new formulation of an optimization problem is proposed, being the solution provided by genetic algorithm. Simulations are conducted using the IEEE 33-bus test system to validate the proposed method proving its efficiency and robustness.

Controle Baseado em Potência Aplicado em Geradores Distribuídos em uma Microrrede de Baixa Tensão

Wellinton M. A. Agostinho — 2022-11-30

This work consists in the application of the power-based control technique in the management of power flow in distributed energy resources connected to a low-voltage microgrid. The microgrid is composed of six single-phase H-bridge converters, three connected between phase-neutral and three with phase-phase connection sharing a single DC bus controlled by an active PWM (Pulse Width Modulation) rectifier. The converters used are current mode controlled, injecting or absorbing active and reactive power in the micro-grid to meet the specifications of the AC grid. A low speed communication structure based on the CAN 2.0 protocol establishes the communication between the DERs and the master controller, which is responsible for determining the energy contributions of each converter allowing the proportional sharing of power among them and regulating the power flow in the PAC. The results obtained through the experimental prototype, show that the power based control, guarantees in permanent regime a stable active and reactive power following the requested reference and the proportional sharing of power among the DERs according to their maximum capacities.

MeanShift para Densificação de Dados Aplicado à Previsão de Geração de Energia Eólica

Hellen Dianne P. de Souza — 2022-11-30

The forecast of wind energy generation is used by many energy companies in order to safely estimate the wind resource and in this way guarantee both the company and the consumer the increase in revenue and the supply of energy from a renewable source over a period of time. Some techniques were developed for this purpose and allow estimating the wind resource and the energy generated for a few hours, days or even weeks. In this work, an information theoretic learning technique for the densification of a wind measurement database is presented, generating new data with the same probability density function of the original set until obtaining the mode of the set, using these virtual data as scenarios of the forecast.

Estudo Comparativo da Implantação e Operação de Usinas Maremotrizes

Leandro Borges — 2022-11-30

The constant and growing demand for electricity challenges the energy sector to seek new sources of power generation, like the oceanic energy. This type of source has a large theoretical production capacity and due to energy conversion technologies it is observed that the use of tidal energy capacity can occur in several ways: by employing the amplitude variation between ebb tide and flood tide, using a reservoir to harness the potential energy stored in the water column; or by the tidal currents created by the movement of water masses, harnessing the kinetic energy of the fluid. Each of these forms of use has its characteristics, advantages and disadvantages. This paper aims to compare the operation of two tidal power plants, one based on tidal current and the other based on tide height variation, in the state of Maranh˜ao, considering different aspects such as energy generation within the same time cycle, costs and environmental impacts. The simulations are carried out using real data collected at anchorage in the S˜ao Marcos Bay and tide tables provided by the Brazilian Navy.

Análise de Impacto da Inserção de GD nas Tipologias de Carga

Fernando Zaquine Martins — 2022-11-30

The article presents an analysis of the impact of DG insertion on typical load curves (typologies) of low voltage residential and commercial consumers. The analysis was based on a sample of consumer load curves with and without DG installed, from an energy distribution company in Brazil. The definition of typologies, considering DG or not, was done through an unsupervised technique (clusterization). The results obtained demonstrated that the consideration of DG can have a relevant impact on residential and commercial typical load curves and that, given the characteristic of the DG profile and the consumption class, the impacts can have different magnitudes from the perspective of segregation distribution system costs.

Correlação entre Geração Distribuída e Fatores Sociais no Brasil Utilizando Conjuntos Fuzzy

Renan Moreira Soares — 2022-11-30

Due to the potential for photovoltaic solar energy, the growth of distributed generation has advanced in Brazilian recent decades. Government incentive policies are also reasons for this expansion. As a reflex, we can mention the increase in direct and indirect jobs, which reflects in the economy, improving aspects of society and social indicators. These indicators can be translated into an economic and social characteristic known as poverty, a multidimensional measure, having different levels. Due to this characteristic of uncertainties, poverty can be described by the theory of fuzzy sets. In this way, in this work, a fuzzy poverty index was built taking into account 17 different social indicators, which together describe development, quality of life and poverty. With this index and possessing the installed power data from the distributed generation, suitable for the nebulous set, a correlation study between the two variables was carried out. For this, four cases were considered, with regional and state data in two different periods (2013 and 2021), in order to verify the correlation. In possession of the results, an analysis was carried out, showing the existence of the correlation.

Uma Revisão Qualitativa do uso da Blockchain na Infraestrutura de Veículos Elétricos

Lucas Vargas Dias — 2022-11-30

Due to the popularity of Blockchain technology, there have been many proposed applications of it in the Vehicle Electric Infrastructure (VEI). In this way, this work presents an overview of some proposals based on their Blockchain’s utilization. Therefore, it provides a qualitative analysis of them and gives an overview of Blockchain technology and consensus algorithms. Finally, we indicate some future works and opportunities.

MIGRAÇÃO DE CONSUMIDOR DE ENERGIA ELÉTRICA PARA O AMBIENTE DE CONTRATAÇÃO LIVRE COM DEMANDA INFERIOR A 500kW

Natália W. Rovaris — 2022-11-30

The Free Contracting Environment continues to conquer new consumers, in 2020 it registered a new migratory wave, with about 23% growth in relation to the previous year. It currently covers approximately 30% of Brazilian electricity consumption. This expansion is due to the advantages provided by this energy contracting environment. When a consumer joins the free energy market, he buys energy in free competition, has more financial predictability and can also encourage sustainability on the planet through the purchase of energy from renewable sources. Nevertheless, for a consumer to be eligible for the Free Contracting Environment, it is necessary to have a minimum contracted demand of 500kW. For 2021, a regulatory change was made, where the disclosure of the Settlement Price of Differences (PLD) became hourly, changing the results of Financial Settlement. This work aims to study the feasibility of migrating to a consumer-free environment with demand initially below 500kW, considering the new hourly Settlement Price of Differences (PLD). For this, the proposed methodology for comparing the feasibility in the two environments is presented. The application of the methodology is carried out with six consumers, with the load curves of three consumers being real and three are hypothetical curves, in the latter case with half the demand of the previous curves. The results obtained show that it may be possible for a consumer with a demand below 500kW to adapt and migrate to the free market. However, it depends on two crucial points: the percentage of consumption in peak hours in relation to total consumption and the price of long- term energy.

Metodologia de apoio à operação de sistemas elétricos de potência baseada em identificação de sistemas com aprendizado de máquina

Ricardo R. Almeida — 2022-11-30

Recent advances on synchro phasor measurement along with its regulation by the Operador Nacional do Sistema – ONS brought access to high resolution data with rates up to one sample per cycle. Electrical power system current, voltage, phase and frequency are collected through Phasor Measurement Units-PMUs and stored in Phasor Data Concentrators – PDCs. Such high-resolution data favours new algorithms and applications towards electrical power systems dynamic behaviour, once unattainable due to supervisory control and data acquisition system limitations. Implementations regarding real time operations help control room operators’ awareness and reactions under electrical power system disturbances and malfunctions. System identification methods, together with artificial intelligence tools such machine learning, contribute to research and development on real time supervisory control. In this study a classic system identification algorithm is implemented to process dynamic electrical power system data and find a model representing its behaviour through PMU data. A stabilization diagram is applied as a post processing method and results used to build a histogram underlining electrical power systems electromechanical modes.

Lógica Fuzzy e Geoprocessamento para Instalação de Usinas Eólicas Offshore nas Regoões Sul e Sudeste do Brasil

Karen F. Paula — 2022-11-30

The search for renewable and efficient energy solutions has become a global trend due to the current climate change scenario and the increased demand for electricity. Thus, in several countries, the share of renewable sources in the electricity matrix has grown with the insertion of new energy sources, such as wind. This energy source has significantly contributed to the global energy transition and the trend is for the growth of wind energy to migrate to the sea. Brazil has good conditions for offshore wind farms as it has an extensive coastline and extensive experience in offshore operations in oil and gas. This paper presents a methodology that seeks better use of the wind resource available in the areas with the highest electricity consumption in Brazil to help planners and agents interested in new projects for the construction of offshore wind farms in Brazil’s South and Southeast regions. First, the proposed method evaluates the available wind resource considering technical, environmental, and social constraints, to identify the best offshore wind farms on the Brazilian coast. Considering that these restrictions present a high spatial dispersion in the study area, the proposal performs the information processing within a geographic information system. Then, a fuzzy logic model makes the joint evaluation of the constraints. As a result of the study, there are the 25 most favorable locations for the deployment of offshore wind farms.

Simulação e Análise de Transientes Atmosféricos em Sistemas de Carregamento de Veículos Elétricos

Igor Rodrigues De Nardi — 2022-11-30

As electric vehicles and renewable energy expand, there is also a need to investigate new methods of lightning protection for these new technologies. This paper aims to evaluate the performance of electric vehicle charging systems against lightning during their transitory regime. Models of two charging stations, one connected to the AC power network and the other disconnected, were used for the simulations. Additionally, a lightning transient model were used too. The results of this paper showed the changes in the waveforms at the input and output of the circuits, making it possible to assess which points are more vulnerable, requiring a better protection.

Extração de Dados via Web Scraping como Suporte em Análises Envolvendo a Geração Distribuída

Renan Moreira Soares — 2022-11-30

In recent years, relevant growth has been evidenced in the photovoltaic generation sector in Brazil. The analysis of this growth is fundamental for decision-making, both in the public and private sectors. This growth can cause major impacts, both on the electrical system and on the quality of electricity delivered to consumers. Therefore, investigating the factors that can influence this increase is of supreme importance so that actions and investments can be carried out towards the improvement of the electricity networks. To verify the influence of these socioeconomic factors on the growth, statistical studies have been developed. However, to carry them out, a huge amount of data needs to be collected to ensure robust analysis. These data can be collected manually, on the internet, on the websites where are available. However, this manual retrieval is slow, error-prone and can compromise data reliability. So, in this work, web scrapers tools are presented to collect data from two different sites, supporting different research that can be carried out on the growth of distributed generation. At the end, an analysis with the collected data is shown, demonstrating the usefulness of these tools.

Inclusão do Efeito da Frequência em um Método Alternativo de Integração das Equações de Estado de Linhas de Transmissão

Higor Ferreira da Silva — 2022-11-30

This article proposes an alternative method to compute the currents and voltages along overhead transmission lines (TL) represented by the lumped model using a cascade of p-circuits, considering the frequency effect on the longitudinal parameters of the line. The alternative method simplifies the formation of state matrices reducing their dimensions, without affecting the performance of the simulations. The alternative method was used to compute the electromagnetic transients resulting from the switching maneuver in an overhead transmission line in several scenarios. The results demonstrated that the alternative method has the same precision as the classic method, and the dimensions of the state matrices are much smaller in comparison with those employing the classic approach.

Avaliação de métodos para detecção de descargas parciais em transformadores

Fernando G. K. Guarda — 2022-11-30

In this paper, several methods for detecting partial discharges in transformers will be discussed. The occurrence of partial discharges in electrical equipment is of great concern to energy companies, as they are defects that are often not noticeable during a visual inspection. This causes the partial discharge to evolve into a more severe defect, often causing the need to remove equipment from service. The different methods for detecting partial discharges will be discussed and their characteristics and applicability will be investigated. In addition, the main advantages and disadvantages of each method will be presented.

Estudo Comparativo do Ajuste de Funções Racionais em Modelos de Linhas Aéreas de Transmissão

Túlio Oliveira Silva e Assunção — 2022-11-30

The overhead transmission lines are subject to several transients events, such as atmospheric discharges. For this, the study of electromagnetic transients in transmission lines is fundamental to know the response of this element before the electrical power system in cases of unexpected requests. In the existing line models in electromagnetic transient softwares, a required step is the fitting of the functions that model the line in rational functions. Therefore, this paper aims to analyze the difference between two methods of rational approximation in the study of electromagnetic transients in a single-phase overhead transmission line. The two methods used are: i) Asymptotic Bode Fitting (ABF); ii) Vector Fitting (VF) . The analyzed models are computed considering a frequency spectrum from 100 Hz to 10 MHz. According to the results, the use of the most complex model, VF, can lead to mean square errors up to 36 times smaller than those resulting from the use of the traditional ABF implemented in electromagnetic transient software, such as ATP.

Abordagem de Controle para a Operação Descarregada de Plantas Fotovoltaicas de Grande Porte

Eric Bernard Dilger — 2022-11-30

The increasing integration of photovoltaic (PV) generation in power systems reduces the frequency regulation capability and deteriorates the frequency dynamic behavior, highlighting the importance of PV generation support to the grid ancillary services. The de-loaded operation is one of the control approaches which enable PV systems to participate in frequency regulation and inertial response support. However, the estimation of the maximum available power in large-scale PV power plants is a relevant technical challenge for the de-loaded operation. In this context, this work proposes a control approach to allow the de-loaded operation of large-scale PV power plants. The proposed approach enables real time estimation of the maximum available power by scanning the P-V curve of the PV array. The proposed control approach was evaluated and validated in a 100 MWac PV power plant, considering realistic irradiance variations generated by fractals that emulate the typical movement of clouds. The results have shown the effectiveness of the proposed strategy in estimating the maximum available power and tracking the power reference defined by de-loaded margin.

A Regulação Brasileira de Geração Distribuída Aplicada em Diferentes Estados e Distribuidoras

Maressa Tuponi Santos — 2022-11-30

This article presents the state of the art of distributed generation (DG) regulation in Brazil. For this, a critical study will be carried out on the interpretation of regulation by distributors in the Southeast region of Brazil. We highlight the differences between the connection processes, the taxes levied on the energy tariff and on the TUSD (tariff for the use of the distribution system) of customers with DG and the collection of a minimum consumption of 100 kWh. This study portrays how the different views and interpretations of regulation affect the market, both for customers and for companies in the energy business. As support for the assessment will be used energy bills from consumers with distributed generation from three different power suppliers located in the states of Rio de Janeiro, Minas Gerais, and São Paulo. In this way, a more assertive and comparative analysis will be presented, based on the premise of the current regulation of the Brazilian electricity sector in 2021. As a result, the existence of different interpretations of the regulatory standards between the EPD was verified. Two out of three studied EPD charge tax on the TUSD portion of the energy tariff, one of the distributors does not inform in its invoice the customer's energy credits and one distributor requires the physical delivery of all documentation necessary for the connection process.

Análise de Ocorrências de Ilhamento não intencional em Parque Eólico conectado ao Sistema Elétrico de Potência

Roberson Adriel Bergmann Ledebuhr — 2022-11-30

Esse artigo apresenta os resultados alcançados após analisar duas ocorrências de ilhamento n˜ao intencional de geradores eólicos, originados a partir da correta operação da proteção de linhas de transmissão. Na primeira ocorrência analisada o parque eólico permaneceu alimentando a carga da cidade, a ele conectado. A falta ocorreu na linha de interconexão com outras cidades, isolando assim o parque e a cidade até a reconexão da Linha de transmissão (LT), 30 s depois. Na segunda ocorrência analisada o parque ficou isolado do sistema e parte dos aerogeradores ficaram alimentando o serviço auxiliar de outras maquinas. Elas permaneceram até o momento em que a equipe de operação interveio e desligou manualmente.

Análise das Variações de Potência em Plantas Fotovoltaicas de Grande Porte

Eric Bernard Dilger — 2022-11-30

Output power fluctuation is one of the biggest concerns in photovoltaic (PV) generation. The power variability of short time scale, which is mainly caused by ground shadows generated by cloud movement, can deteriorate the frequency and voltage magnitude of power systems. Besides affecting the power quality, the typical output power fluctuations impose some challenges to the planning, operation and control of power systems. Thus, the understanding of the aspects that affect the power variability and the typical magnitude of these variations is fundamental to the proposition of operational and control approaches to mitigate the adverse effects caused by utility-scale PV systems. In this context, this work evaluates the impact of multiple meteorological conditions and technical parameters on the output power variability of PV power plants. Fractals are used to formulate an approach capable of synthesizing the global irradiance time series necessary to evaluate the output power variability. The results obtained from a case study of a 100 MWac PV power plant have showed that the meteorological conditions and the plant rated power play an important role in the magnitude of the output power fluctuations. The proposed approach and its outcomes may contribute to the proposition of new operational and control approaches to mitigate the adverse effects caused by PV power plants.

Análise Comparativa Entre Modulação Multinível Clássica e Multi-taxas em Aplicações de Acionamentos de Motores de Indução

Guilherme A. R. Cota — 2022-11-30

Semiconductor based electrical drives are used in a variety of applications due to the possibilities and advantages of their usage in machine velocity and torque control. In this context, this work presents computational studies of multicell power converters applications for high voltage induction machine drives using classical and multirate modulation techniques. Due to novelty of the chosen multirate techniques, there is a demand for more studies using it, especially in electrical drives applications since the majority of the conducted studies are for energy conditioning systems and d.c.-d.c. converters. Therefore, this paper proposes a comparative analysis between classical and multirate modulations for electrical drives applications. The computational studies are conducted with the PLECS software due to its capabilities to calculate the converter’s losses considering the electrical and thermal models of the semiconductor switches. The comparative analysis is conducted for converters with several different number of cells and switching frequencies, with the evaluation of both the output voltage and current waveform quality, as well as the converter’s total losses.

Controle da Tensão de Saída de um Sistema IPT por Estimação de Estado Utilizando o Filtro de Kalman

Macklyster Lãnucy S. S. de Lacerda — 2022-11-30

Nowadays, inductive power transfer systems (IPT) have located numerous application, highlighting for example the charging of cell phone batteries, and electric vehicles. In the present article, the IPT is applied in such a way that the load voltage is kept constant, and it is implemented a Kalman filter that utilizes a signal synchronized with the inverter output voltage and the voltage measured at the rectifier switch as input variables. As output signal, the filter provides the voltage across the secondary compensation capacitor. The output of the Kalman filter is used as one of the switching signals of the rectifier that supplies the load. Computer simulations are performed in the Matlab environment for different values of load resistance and coupling factors of the IPT, where the maintenance of the load voltage is perceived.

Sintonia de controlador utilizando Recozimento Simulado para amortecimento das oscilações eletromecânicas

Elayne Holanda Madruga — 2022-11-30

Some disturbances can affect power system stability and generate electromechanical oscillations. In this paper, a robust controller design is presented, whose main objective is to damp the electromechanical oscillation modes and ensure power system stability. In order to guarantee the robustness of the controller, singular values and Relative Gain Matrix were used to select the most significant input- output pairs in the system. The designed controller was of low order and its parameters were adjusted using Simulated Annealing. It was observed, when these parameters were used, the system was damped and it met the robustness condition. A comparison was also made of the result with other optimization methods. Simulated Annealing showed a good comparative performance and it proved efficient for nonhigh uncertainties.

Balanço Energético de um Laboratório de Pesquisa em cenários pré, durante e pós pandemia, visando certificação nZEB

Matias R. M. Lavôr — 2022-11-30

Photovoltaic systems have an essential role to improve the energy efficiency of buildings. In this regard, this study seeks to present an analysis of the energetic balance in different chronological scenarios for the building of the Center of Excellence in Energy Efficiency of Amazon - CEAMAZON, a public institution for Research, Development and Innovation, linked to UFPA, located in the Science Park and Technology of Guamá. Additionally, it is shown a short analysis of the new INI-C related to the nZEB evaluation methodology, including the new distributed generation system implanted, highlighting the set of building characteristics that can classify its energy efficiency, and demonstrating essential parameters for certification.

Metodologia para Gerenciamento de Risco Econômico em Sistemas de Potência que Integram Geração Renovável

Cristian A. Alvez — 2022-11-30

The operation of electric power systems is exposed to risk situations due to the presence of random parameters. These random parameters can cause technical and economic losses in the operation of the systems if they are not managed properly. This work presents a methodology for economic risk management in power systems that integrate renewable generation. The methodology combines the concept of value at risk and simulation with time series to manage risk from a non-conservative approach, so that the system operator chooses the level of risk he is willing to face. To illustrate an application of the proposed methodology, it was compared with a conservative approach to risk management. The results show that a non-conservative approach is more adequate to assess risk in systems that integrate renewable generation. Finally, it is highlighted that the proposed methodology can support the planning and operation of power systems.

Sistema Inteligente para o Controle de Dispositivos Elétricos/Eletrônicos e Consumo de Energia Elétrica em Residências de Alto Padrão

Elton de Sousa e Silva — 2022-11-30

The evolution of the Internet of Things (IoT) is positively impacting people’s lives. With the increasing advancement of technology, homes are being automated with electronic devices, which are available to be programmed with intelligent software, to be functional, keeping people comfortable and reducing costs with electricity consumption . This work presents a proposal for a software based on artificial neural networks (ANN) to manage the devices in a home, using an automatic system to minimize the consumption of electrical energy with the least impact on the comfort of its residents.

Composição e Avaliação de Estratégias de Controle de Subtensão em Redes de Distribuição Causada pela Recarga de Veículos Elétricos

Hugo H. S. Santos — 2022-11-30

This paper aims to evaluate the effectiveness of four techniques applied to the inverter of electric vehicles for the mitigation of undervoltage occurrences due to the charging of electric vehicles in a low voltage network. The techniques employed are: Volt-Var control, Volt-Watt control, controlled recharge strategy, and the combination of controlled recharge and Volt-Var control. The simulations were conducted in a real system located in the southern region of Brazil, using OpenDSS and MATLAB software. The results show that the Volt-Var control exerts less influence on voltage control, but the controlled recharge together with the Volt-Var control proved to be more effective for this purpose.

Exploração da Complementaridade Eólica - Solar no Uso Eficiente dos Contratos de Uso do Sistema de Transmisão de Energia Elétrica

Rafael B. S. Veras — 2022-11-30

In this paper, the exploration of the complementarity between renewable sources to improve the use of the transmission capacity contracted by the generating agent considering the new rules established by the Brazilian regulatory body is proposed. To quantify the complementarity between sources, the Pearson coefficient is used. The results of the case study prove that the exploitation of complementarity through the implementation of hybrid projects based on renewable energy sources leads to significant gains in the exploitation of the transmission contract, thus bringing benefits to the generating agent.

Impedância de Surto de Sistemas Elétricos Constituídos por Múltiplos Condutores Verticais

Gabriel Carlos Pena da Silva — 2022-11-30

Transmission towers are an essential component for the functioning of a country’s electrical system. In countries with a large extension of transmission lines and a high incidence of lightning, problems related to the interaction between lines and lightning are quite intense. Thus, it is of fundamental importance to develop models that compute the response of the transmission system when an electromagnetic transient is established. This article aims to present the revised Jordan formula for calculating the surge impedance of a vertical conductor, and its extension to calculate the surge impedance of multiple vertical conductors. Neumann integrals are also applied to calculate the self and mutual surge impedances of vertical conductors. The results of surge impedances, of typical towers of 138 kV transmission lines, from the application of modified Jordan formulas and Neumann integral equations are compared. According to results, for 138 kV transmission towers, the percentage differences are smaller than 1%, proving the accuracy of Jordan’s modified analytical formulas.

Alteração nas correntes de curto-circuito com elevada integração de geração distribuída fotovoltaica

Amauri Cesar Cristofano Junior — 2022-11-30

With the advancement of technology, lower prices and low environmental impacts, the use of photovoltaic generators is becoming increasingly viable, studying the effects of the high integration of photovoltaic generators in the electrical system, on short-circuit currents, for example, they will indicate that the electrical system will need to prepare to avoid or mitigate such effects. One of the most used and efficient ways to analyze the effects caused by the massive insertion of photovoltaic generators is to carry out studies in computer simulators, such as OpenDSS and Pycharm software, which mathematically simulate circuits, calculate short-circuit currents and automate and the insertion of photovoltaic generators in different scenarios. With this variety of data and scenarios generated, the behavior of the studied systems is very close to reality. In this study, the single-phase and three-phase short-circuit currents were analyzed, verifying the greatest variation during the insertion of photovoltaic distributed generation in the points of the system which have loads. The photovoltaic generators will be inserted in different ways and the short circuit currents will be calculated at each insertion.

Estudo de Viabilidade de Implementação para um Sistema de Geração de Energia Hibrida em Propriedades Rurais

Orlei Petry Junior — 2022-11-30

When dealing with electric energy, its production and distribution in rural regions, its production and distribution in rural regions, it is relevant to observe peculiar aspects from the lack of infrastructure or the seasonality of the climate in our country. Both points must be observed in the face of difficulties in accessing electricity generation for rural producers in more isolated regions. As an alternative, hybrid electrical energy systems have been studied and used. The objective is to seek the supply of electricity in areas where the distribution networks do not reach, or as a way of generating credit to reduce energy consumption. Therefore, this study presents the dimensioning of two forms of electric energy generation, solar energy and biomass energy. Making consumers in the same concession area benefit from production. For the theoretical basis, research from different authors was used, as well as technical documents from the National Electric Energy Agency to determine the predicted electric energy generation in kWh. The maximum energy demand, in Watt, was also evaluated to supply up to 20 properties with an average monthly consumption of 450 kWh.

Avaliação das Violações dos Limites de Tensão em uma Rede de Distribuição de Energia Após Inserção de Geração Distribuída Fotovoltaica

Izadora Soares Cardoso — 2022-11-30

This paper presents an evaluation of the voltage values at the common coupling point of a secondary electricity distribution network after the insertion of a photovoltaic distributed generation unit. With the evaluation it was possible to verify whether after the insertion of photovoltaic distributed generation there was a violation of the voltage limits determined by the National Electric Energy Agency. To evaluate the voltage values, computer simulations of a real distribution network were carried out, considering its constructive characteristics, as well as the power demand of the consumer units connected to the network, the installed power of the generation unit and the local solar power and temperature. The simulations were carried out considering the months of the year to analyze the influence of seasonality on the change in the simulated voltage values. With the results, it was found that the insertion of photovoltaic distributed generation can cause more than 20 violations of the voltage limit over the months, causing financial damage to the energy concessionaire. Voltage limit violations occurred 45.83% of the time at 1 pm, indicating that the occurrences are recurrent at times of high generation and low consumer demand, increasing the voltage value at the common coupling point of the distribution network. From the results obtained, it is possible to identify the instants in which the operation of the protection system of the distribution network is compromised, so that later it is possible to propose methods to regulate the voltage at the point of common coupling.

Estudo comparativo entre linhas de transmissão aéreas convencionais e compactas com vistas à faixa de segurança e capacidade de transmissão

L. E. B. Andreata — 2022-11-30

Nowadays the construction of conventional overhead power lines has faced several constraints, with the increasing need of reducing right-of-way limits, especially in urban areas, and increasing power flow within the same right-of-way of existing lines. In this context of restrictions, transmission lines compaction has become a possible option. This work investigates how new compact overhead power line technologies influence its electrical parameters, particularly, those which influence the right-of-way width calculation, such as surface gradient, electric field, audible noise, and radio interference, as well as those related to power flow capacity, that is, surge impedance and surge impedance loading (SIL). The results show that it is possible to reduce right-of-way width using compact configuration with reduced distances between phases, as well as improve power capacity.

Impactos da Alta Integração de Geradores Distribuídos nos Níveis de Energia Incidente de Alimentadores de Distribuição

Matheus dos Reis Bravim — 2022-11-30

The generation of electricity from sources close to the consumer has grown enormously due, among other factors, to the global concern with reducing the emission of pollutants and the economic benefits for the user. Despite the advantages, the insertion of another sources in distribution networks can cause changes in feeder parameters. Incident energy is one of the most relevant risks associated with an electrical arc in an electrical installation and is directly linked to its short-circuit current levels. This study proposes to study the behavior of incident energy levels of a radial distribution feeder for different scenarios of integrated photovoltaic distributed generation. OpenDSS simulation software was used, as well as incident energy calculation methods accepted by NPFA-70E. As a result, it was observed the maintenance of the energy incident values and the original arc flash boundary when there is high integration of distributed generation, while the reduction of energy incidence and the arc flash boundary was observed when there is less integration of distributed generation.

Arquiteturas de microgrids baseadas em fontes híbridas para recarga de veículos elétricos

Leonardo André Maia — 2022-11-30

According to the Brazilian Electric Vehicle Association (ABVE), between January and October 2021, 27,097 electric vehicles (EVs) were sold in Brazil. This is a sales record for this type of vehicle, an increase of 74% compared to 2020. However, the country still lacks infrastructure for charging, either due to lack of regularization or the high prices of EVs practiced in the country. Taking advantage of this scenario, the proposal of the article is to present architectures of microgrids based on hybrid sources for recharging EVs. Such arrangements rely on the integration between the electrical grid, energy storage system and renewable energy sources (RES), to recharge EVs and other loads, both in direct current (DC) and alternating current (AC), offering, in addition to environmental benefits from using RES, operational advantages such as improvements in energy quality, reliability and availability.

Alocação Otimizada de Medidores para Localização de Faltas utilizando Medições de Tensão

Paulo E. T. Martins — 2022-11-30

This work presents a Binary Integer Linear Programming (BILP) formulation for the problem of optimal allocation of meters, considering two objectives: minimizing the number of meters and maximizing the number of identifiable faults. The problem was tested on a 15- bus European Medium Voltage System of CIGRE´, considering the inclusion of a distributed generator and the possibility of operating the system as a weekly meshed network. Instances with solid single-phase A-ground faults were generated, uniformly distributed throughout the system. The optimization problem was solved through the Algorithm for Bicriteria Discrete Optimization (ABCDO) and the Nondominated Sorting Genetic Algorithm (NSGA-II), obtaining solutions with 1 and 2 meters. The meter allocations obtained were used to feed a fault locating algorithm based on voltage measurements. The results showed a reduction of multiple fault estimation regions, which is interesting for application in modern distribution networks.

Alocação de Medidores de Qualidade de Energia para Sistemas de Distribuição Utilizando Algoritmos Genéticos

Júlia O. Fernandes — 2022-11-30

Considering the current energy scenario, technological developments and, especially, the global economic context, it is necessary that the power quality supplied by utilities is constantly monitored, since disturbances of the most diverse classes and orders affect the power distribution system. Therefore, the allocation of power quality meters in distribution system has been increasingly adopted to prevent and even impede major losses to consumers and the utilities itself. In addition, every system has locations where power quality measurement is even more relevant and which can be considered as strategic measurement points. Thus, this work proposes a method of allocation of power quality meters for power distribution systems through genetic algorithms in conjunction with the singular value decomposition technique, which establishes the position, quantity and type of meter to be allocated, be it voltage or current, in order to guarantee, in a more economical way, the total observability of the system. The methodology was validated through tests using the IEEE 34-bus distribution system through two different scenarios taking into account the strategic points of this system. In comparison with other related works used the same system scenarios for testing, the algorithm proved to be more effective by reducing the number of equipment to be installed to ensure total system observability.

Capacitor placement in unbalanced distribution networks to minimize reactive and unbalance power losses

Marcelo Semensato — 2022-11-30

In this paper, the optimal placement and sizing of capacitors for the compensation of the reactive power and the unbalance power in medium voltage distribution networks with unbalanced loads is proposed. The proposed capacitor allocation reduces power losses in power networks caused by reactive power demand and unbalance. The powers are calculated by the IEEE STD 1459-2010, and presented real values of electrical magnitudes in unbalanced three-phase systems. The results of the capacitor placement obtained from the proposed method are compared with the placement of single- phase capacitors and the placement of balanced three-phase capacitors banks. The results allow to observe the efficient performance of the proposed method for reducing power losses in a 34-bus medium voltage power network with the presence of the neutral conductor. Four cases are simulated with results optimized by the Chu-Beasley genetic algorithm. The purpose of the optimization algorithm is to minimize line loss and capacitor costs.

Aplicação da Programação Dinâmica na Coordenação Hidrotérmica de Sistemas Elétricos com Inclusão de Usinas Hidrelétricas Reversíveis

Clóvis da Conceição M. Martins Júnior — 2022-11-30

Hydrothermal scheduling is a relevant stage of operation planning, whose objective is to minimize the total cost of operation, together with respecting the restrictions of electrical systems such as transmission losses and the power balance throughout of the demand horizon. In recent years there has been an increase in interest in the implementation of pumped-storage hydroplants in electrical systems in order to operate in conjunction with intermittent sources. With this new paradigm, the problem of hydrothermal scheduling has become more complex. This paper aims to apply the dynamic programming technique to solve the hydrothermal scheduling problem with the inclusion of pumped-storage hydroplants. The procedure is applied to an equivalent test system, and it is possible to obtain a lower cost in relation to the base case together with the established restrictions.

Aplicação de Redes Neurais Artificiais para Estimação de Indicadores de Segurança Estática e Dinâmica de Sistemas Elétricos de Potência

Daniela C. R. Souza — 2022-11-30

Nowadays, with the increase of fear of blackout events due to society's increased dependence on electricity, the development of studies related to the power systems security analysis is one of the main activities to be carried out within the scope of planning and operation of electrical grids. Thus, this subject has been debated in the literature for a long period of time and with the advancement of computational power, lots of studies are developed using artificial intelligence techniques for the prediction of indicators related to the power systems security analysis. In this context, this article presents the development of a model, using artificial neural networks, which will work together with power system analysis software for prediction safety indicators, static and dynamic, of electrical power systems.

Recarga Inteligente de Veículos Elétricos Considerando Diferentes Modelos Tarifários Visando Benefícios para a Concessionária e Consumidores

Kaio H. S. Forte — 2022-11-30

This paper proposes a smart charging method using linear programming to minimize the EVs charging costs and attend transformer capacity constraint, reducing the negative impacts of uncoordinated charging, bringing benefits for both utility and consumer. Simulations are conducted through OpenDSS software in a real distribution system in Brazil. Several penetration levels and different electricity tariffs are considered. The results show smart charging can efficiently reduce energy costs and mitigate some negative effects of uncoordinated charging, even for high penetration levels of electric vehicles.

A Localização de Faltas em um Sistema de Distribuição de Média Tensão com Geração Distribuída via Redes Neurais Artificiais

Leonardo Alves Paiva — 2022-11-30

This work aims to address the problem of fault location in a medium voltage distribution system in the presence of Distributed Generation (DG), applying artificial intelligence. The chosen method is learning-based through Artificial Neural Networks (ANNs). The methodology consisted of simulating three-phase faults via PSCAD/EMTDC software, pre-processing (normalization and formatting of training and test sets), empirical tests, routine tests without DG, routine tests with DG, and choosing the best ANN topology. The results presented illustrate the applied tests and the best ANN topology found.

Uma Breve Revisão sobre Simulações Digitais em Tempo Real Considerando Geração Eólica Aplicadas em Problemas de Qualidade da Energia Elétrica: o Estado da Arte

William Brasileiro do Carmo Borges — 2022-11-30

This work presents a review of the research on electrical energy quality focused on wind generation systems, with the application of real-time digital simulation and hardware-in-the-loop techniques to solve the problems. In this bibliographic survey, the main norms are raised, are detailed the types of possible tests and the main publications of the genre. This work can be used as a reference for the proposal of new developments in this area.

Veículos elétricos em redes de baixa tensão - Impactos na qualidade da distribuição de energia

A. G. L.Ferreira — 2022-11-30

One of the main challenges of sustainable development is global climate change, resulting from the intense consumption of oil and coal derivatives. The transition towards a carbon-free world will be a challenge for this and future generations. The electric energy sector, due to its renewable sources of energy generation, such as photovoltaic (PV) and wind, becomes one of the main agents in the decarbonization of the global economy. In this context, electric vehicles (EV) gain great importance, as the transport sector is currently responsible for the emission of about a quarter of the total emissions of greenhouse gases, therefore, EVs can be seen as being a potential solution. This paper seeks to analyze, through a simulation in the OpenDSS software, plug-in electric vehicles connected in low voltage networks, aiming to identify how they can influence different aspects in the distribution networks, especially regarding voltage drop, active losses and overload in the transformer, through the different charging modes (slow, intermediate and fast), so that it can be seen that there was an influence on the worsening of the quality levels.

Coordenação e Otimização de Carregamento de Veículos Elétricos e Despacho Econômico de Geradores Distribuídos Utilizando Algoritmos Genéticos

Lucas C. de Rezende — 2022-11-30

In recent years, the concern regarding the use of energy from clean sources has increased considerably, resulting in several new technologies and system models in order to alleviate the greenhouse effect related to the burning of fossil fuels. Electric vehicles and distributed generators from renewable sources are pointed out as solutions to the problem; however, its implementation in the system can cause adversity in the power system, if done in an uncoordinated way. In this study, the objective was to develop a solution using the Genetic Algorithms Method, with the aid of the A Mathematical Programming Language (AMPL) software to obtain an algorithm that optimally coordinates both the loading of the electric vehicles, as the power supplied by each distributed generator in each period of time, in order to respect the operational and safety limits of the electric energy distribution system, of the electric vehicles and of the distributed generators. The method showed satisfactory results in its application and reduced the system cost by approximately 12.19% compared to the system without distributed generators and electric vehicles.

Multi-objective Optimization Approach for the Allocation of Fast Charging Stations and Distributed Energy Resources

Rafael S. F. Ferraz — 2022-11-30

The increasing inclusion of Electric Vehicles (EVs) in distribution systems is a global trend due to their several advantages, such as increased autonomy and reduced price. However, the high amount of EVs requires the installation of sufficient EV Charging Stations (EVCSs) to recharge them. If there is no adequate planning for the EVCSs allocation, it can result in a reduction in the power quality indices such as increased power losses in the system and voltage variation outside the limits established in IEEE Std 1547-2018. Therefore, this paper aims to define the best locations for the installation of EVCSs in the system, in addition to performing the optimal allocation and sizing of Distributed Energy Resources (DERs) in order to mitigate the problem related to voltage levels. Moreover, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) was used with the purpose of minimizing the investment and operation costs and voltage deviation in the system. The validation of this methodology was performed using the IEEE 13 and 34 node test feeders, and it was possible to compare optimized solutions based on the Pareto curve for both systems, which made it possible to minimize the objective functions.

Análise de Componentes Principais para diagnóstico pós-falta em sistemas elétricos de grande porte

Victor F. Müller Jr. — 2022-11-30

Synchronized phasor measurement systems are being widely used around the world, and have become essential elements in the evolution of the operation of large electrical systems. These systems are based on phasor measurement units, called PMUs, which are capable of recording data with a high sampling rate, thus generating a huge dataset. This work presents a methodology for selecting data for post- fault analysis, through dimensionality reduction, using principal component analysis. To validate the proposed methodology, real data related to a recent occurrence in the national interconnected system were used. The validation of the obtained results was done using an anomaly detection algorithm. With the application of the methodology, the possibility of using a data set smaller than the original was proved, while maintaining the characteristics of the attributes. This automatic data selection methodology benefits post-fault analysis due to the performance gain obtained by reducing the electrical attribute dataset, without significant loss in the accuracy of anomaly detection capability.

Avaliação da Criticidade do Campo Elétrico em Isoladores de Vidro

Henrique Dantas Silva — 2022-11-30

This paper presents an evaluation of the electric field criticality and the electric potential distribution in a chain of 69 kV glass insulators. The analysis was performed under different operating conditions: glass chain insulators with cement reduction, with sacrificial ring, with bell touching the glass and under pollution effect. For this, a multhiphysics simulation software was used. As results, it was noted that the cement reduction and the sacrificial ring presence intensified the electric fields values close to the pin of the first insulator of the chain by more than 40%, which could cause flashovers, increase the pin corrosion rate and puncture in the glass, unlike pollution, which didn´t cause significant changes in the electric field. On the other hand, the electric potential distribution along the glass shed of the first insulator remained standardized, with the exception of the cases with sacrificial ring, which resulted in an increase in the electric potential at all points along the glass skirt.

Análise do Fator de Dimensionamento do Inversor em Sistemas Fotovoltaicos Conectados à Rede para Localidades Nordestinas de Clima Tropical Semiárido

José F. B. de F. Filho — 2022-11-30

Designers of solar energy systems constantly opt for a photovoltaic generator power higher than the inverter power, i.e. they consider the Sizing Factor Inverter (SFI) inferior to the unit to reduce costs, however this can decrease inverter lifespan and increase inverter power clipping losses. This research presents the development of a methodology for calculating SFI for northeastern regions with a semiarid tropical climate, considering the influence of this factor on the specific yield of photovoltaic generator and on the performance ratio, and analyze the influence of climatic factors - such as wind speed and relative humidity - in SFI calculation. Results of this research demonstrate it is appropriate to use SFI higher than or equal to the unity to obtain higher rates of energy production and performance ratio for photovoltaic systems installed in regions with a semiarid climate.

Estudo da Influência de Distorções Harmônicas Inseridas por Sistemas Fotovoltaicos no Fator de Potência da Rede Elétrica de Distribuição

Fernando H. G. Schmidt — 2022-11-30

The growth of interest in own energy generation, driven by public awareness of the environment, the price drop of components of photovoltaic systems, rising energy tariffs and incentives given through regulatory resolutions, and more recently by the legal certainty brought by the Law No. 14,300, made the Distributed Generation (DG) sector jump from ground zero in 2012 to more than 9 GW of installed power in about ten years, of which almost 98% were through the photovoltaic solar generation. This exponential growth of the sector raises concerns about the technical and commercial impacts that the accelerated insertion of photovoltaic systems can cause to the country's electrical distribution networks. One of the impacts of this insertion is the drop in the Power Factor (PF) of the network, due to the characteristic of the generators of only injecting active energy, remaining with their consumption of reactive. Another factor - sometimes ignored - but which contributes to the drop in the grid's PF, is the insertion of harmonic components by the photovoltaic inverters. With that, this work will present a study of the impact of the insertion of harmonic distortions by photovoltaic systems in the PF of the electrical distribution network, from three different scenarios.

Análise de Viabilidade Econômica de Sistema Fotovoltaico com armazenamento aliado a Tarifa Branca

Ana Alice Timm Goretti — 2022-11-30

The present work consists in performing an economic feasibility analysis using the economic indicators Internal Rate of Return (IRR), Net Present Value (NPV) and Payback for Low Voltage (LV) consumers that have a photovoltaic system with storage in a battery bank connected to the distribution network. The consumer unit (CU) is charged by means of the White Tariff, which has three tariff stations, called peak, off-peak, and intermediate. The photovoltaic system has two functions, the first is to recharge the battery bank to be used later in peak and intermediate hours, and the second is to supply the energy demand of the UC between the hours of 12 noon and 4:59 pm. The scaling and calculation of the economic indicators are performed by programming code via GNU Octave Software. The results obtained show that the proposed system is economically feasible for consumers belonging to the largest typical load curves.

Mercado solar e a percepção do usuário quanto ao ambiental e financeiro

Bruna Bugarin Tavares Gonçalves — 2022-11-30

The generation of electrical energy through a solar source, using photovoltaic plates, is widely disseminated in the world. There are several advantages in increasing this type of generation: the environment is less impacted, as it is a renewable source, and implementation costs are reduced, meaning that even residential consumers can purchase micro-plants. However, this information is not clear to the entire population. For this reason, a survey was carried out, through a form, on the perception of the academic community about this energy source, with the result shown in this work.

Metodologia para Avaliação de Obras Destinadas à Qualidade do Serviço Utilizando Técnicas de Inteligência Artificial

Bruno J. S. de Sousa — 2022-11-30

The quality of the electricity distribution service has a great impact on consumer satisfaction and on guaranteeing the concession right for distribution companies. For the concessionaire under study, the main indicators of continuity of service are at levels below the regulatory limits, but due to budget restrictions, the forecast of benefit that the structuring works bring to the continuity indicators must be assertive, for an adequate targeting of investments and decision making. In view of this scenario, a methodology was proposed for the evaluation of works aimed at improving the quality of the service, with the estimate of the benefit associated with the reduction in continuity indicators, using concepts of Artificial Neural Networks (ANN) and Genetic Algorithms (AG). The data used were extracted from the distributor's databases and analyzed to identify the input variables and propose prediction models for the outputs of interest. The historical values of interruptions due to causes were considered as input and the results of continuity indicators associated with the types of works studied form the outputs of the model. The RNA topology used was the Multi Layer Perceptron (MLP). The results obtained by simulating the new methodology showed errors almost 100 times smaller for estimating the benefits of the works compared to the current method used by the distributor.

Aplicativo para Projeto de Sistema Fotovoltaico com Armazenamento Utilizando a Tarifa Branca

Jovana dos Santos Argenta — 2022-11-30

White tariff is the new tariff modality for low voltage consumers. Its creation is related to the costs of production, transmission and distribution of electricity, which vary depending on the day and time of consumption. Based on these variations and to encourage consumers to shift their consumption to times of lower energy demand that this new tariff mode was created. Once the use of photovoltaic systems has intensified in recent years, due to the new needs of society and the modern economy, which seek solutions based on minimum aggression to the environment and maximum efficiency, the present work has as its initial intent to combine the adherence to white tariff with the use of a photovoltaic system with storage, so that the user does not need to change his consumption habits. In this way, the scope of the work is the development of an application for educational purposes about electricity tariff and photovoltaic systems for students and consumers, the same was developed to be accessible and totally intuitive for any user.

CONCEPÇÃO E IMPLEMENTAÇÃO DE UM SISTEMA DE MONITORAMENTO DAS GRANDEZAS ELÉTRICAS E TÉRMICAS EM MÓDULOS FOTOVOLTAICOS

Cezar M. Rodrigues — 2022-11-30

In recent years, photovoltaic modules (PVs) have proved to be an alternative for the production of electrical energy with low environmental impact at the installation site. This type of plant can have its reliability and useful life increased through the individual control and monitoring of its electrical and thermal magnitudes. For the reading and transmission of these quantities, a system that allows sending a high density of data over long distances is necessary, due to the high number of modules and their spatial distribution. This article presents a modular alternative for the measurement of thermal and electrical quantities in individual PV modules based on integrated digital sensors. In laboratory tests, the system showed average measurement errors for voltage and current quantities of 0.19% and 0.06%, respectively. During its field operation, a high density of samples was observed throughout the day, with an average response time of 439 ms.

Identificação de Perdas Não Técnicas Através de Método de Classificação e Otimização de Hiperparâmetros, Baseado em Dados Endógenos e Exógenos

Bruno K. Hammerschmitt — 2022-11-30

Non-Technical Losses (NTLs) are problems commonly found in electric power systems distribution, caused by theft or fraud of energy. These problems result in financial losses for distribution utilities as well as consumers, who partially bear the costs involved in the NTLs. In view of this, practices for the identification of consumer units that are committing some type of irregularity in their facilities must be applied. In this scenario data classification models emerge, which based on supervised learning based on endogenous and exogenous historical data, are able to interpret information and label them. One of these models is the Decision Tree, which associated with Machine Learning (ML) techniques for the optimization of hyperparameters can obtain results with high precision in the outliers identification. Thus, this study aims to implement the Decision Tree model to identify consumers with NTLs, and to propose the optimization of Decision Tree hyperparameters following three ML techniques, Bayes Search, Grid Search and Randomized Search. Finally, the results are discussed and analyzed, and considerations are performed on the models.

Metodologia para Identificação de Perdas Não Técnicas em Unidades Consumidoras localizadas em Áreas Rurais com Cultivo de Arroz Irrigado

Henrique S. Eichkoff — 2022-11-30

This work presents a proposal for the identification of non-technical losses in rural consumers directed to irrigated rice cultivation. The methodology employs in the structure of its algorithm, the k- Means and Random Forest methods, for the clustering and classification of data, using as inputs, monthly records of billed energy from a group of irrigating consumers in the county of Uruguaiana/RS. In addition, the algorithm proposed by this study performs the estimate of electricity consumption of rural consumers based on information on crop planting areas and variables of irrigation systems.

Previsão de Vazões Diárias com Redes Neurais Artificiais e Impacto na Formação do Preço de Liquidação das Diferenças Horário

Elson Antonio Nunes Jr — 2022-11-30

As the forecast of inflows to hydroelectric plants is one of the input information in the process of SIN operation programming, it is important that these forecasts are increasingly assertive so that the outputs of this process are more consistent with the real conditions. The main goal of this work is to model a daily inflow forecast using neural network technique whose outputs are incorporated into the very short-term hydrothermal dispatch optimization program in order to analyze the impact on the spot price in the electric energy market. The results regarding the flow forecast showed that the predictor proposed was equivalent or more assertive than the models officially used in the energy sector for a considerable part of the hydroelectric plants evaluated, especially for the first forecasted day. On the other hand, the results referring to price indicated the close tracking of the curve created to the official reference, following even the movements of higher volatility. At the end, a price curve referring to the application of the realized flows is adopted, providing a conclusion about the affluence used as input data for the forecaster.

Análise qualitativa das famílias Wavelet para detecção de descargas parciais em isoladores

Kaynan Maresch — 2022-11-30

Partial discharges (PDs) are undesirable phenomena that can manifest themselves in the equipment that make up the electrical system, and these dielectric breakdowns tend to evolve into short circuits. In order to diagnose the damage caused by PDs in a certain equipment, the energy concessionaires need to take it out of operation and then apply the electrical method. In addition to this, the thermovision method can be used, which only detects damage to the equipment when the ruptures are already severe. This article aims to use the Wavelet Transform(TW) in the processing of information contained in 26 PDs and noise signals, Corona-type with and without saline pollution. As a result, the detection of PDs is performed based on the TW coefficients. For this, it was necessary to vary the TW parameters and find the Wavelet family and level that best suits the PD signals. The TW proved to be suitable for the treatment of ultrasound signals as it is capable of dividing a signal into time and frequency windows. This feature makes it possible to identify whether the ultrasound signal comes from noise that is normal for system operation or from a PD. With this work, it was possible to identify the most suitable Wavelet families for the identification of partial discharges in medium voltage insulators.

Systematic Analysis of Literature on the Social Benefits and Advantages of The Adoption of Intelligent Electric Energy Meters

Carlos J. Santos — 2022-11-30

This article presents a systematic review of the literature on the use of smart meters. The current approach has shown a focus on data acquisition and processing and, mainly, on automation, which are certainly important factors. However, the non-technical approach has been little explored. This condition leads to reflection on aspects beyond the technical scope, such as social, environmental and economic. This work contributes to broadening the vision of researchers in the field of smart grids, presenting the main aspects of the works that the authors' knowledge until now, emphasizing the lack of investigations beyond the purely technical nature, leading to the conclusion that there is still much to explore in the social field through the implementation of smart grids

Microgrid Operational in a remote village of Abricots in Haiti

Sylvain René — 2022-11-30

As we approach 2030, Haiti is among the countries where access to electricity is difficult, with less than 45.4% electrical coverage (2019); According to a report by "The Spectator Index" published in January 2018 regarding the least electrified countries in the world. A present, Haiti is the third among the worst in the world (in 2017), after Nigeria (2nd) and Yemen (1st). The problem of lack of access to electrical energy is a major obstacle to the economic and social growth of the country. Diagnostics on the Haitian electrical system prove that the production costs of electrical energy are very high and the commercial losses are enormous, even deficit. This article reviews the literature and proposes the use of an off-grid microgrid based on solar energy to supply 271 households in the village of Abricots, a community clearly isolated from the rest of the country, in order to facilitate sustainable access to electricity for this marginalized population of Haiti. This study allows us to understand the feasibility aspects of the project, to size the components of the microgrid, in order to coordinate the supply and demand of energy, while optimizing the operational cost.

An Approach for Load Shedding in Islanded Microgrids

Wesley Peres — 2022-11-30

This paper proposes an Optimal Power Flow for defining the minimum load to be shed to maintain the steady-state frequency between allowable limits in islanded microgrids. The droop coefficients and setpoints (no-load voltage and frequency of each Distributed Generator) are optimized considering the limits of microgrid frequency, nodal voltages, and power generation (apparent and reactive powers). The approach is applied to a microgrid of 33 nodes, considering a 24 hours time-horizon. The found results point to the methodology effectiveness.

Contribuição ao Desenvolvimento de um Laboratório de Arco Elétrico Controlado para Medição da Energia Incidente

Pedro O. Bacin — 2022-11-30

Arc flashes are events of great electrical hazards and with a destructive power that can lead workers to disability and death, and cause serious damage to equipment. In the last 20 years, there have been significant advances in laboratory tests of arc flash to measure incident energy. For instance, the IEEE Standard 1584 - 2018 shows laboratory setups for tests and provides mathematical models to determine the incident energy. However, the literature is scarce regarding tests under several weather conditions, like moisture and different temperatures. These issues are especially important when it comes to the Brazilian context, since Brazil is a large country with several singularities, and understanding the effects of these conditions on arc flash can be of vast scientific importance. Therefore, this paper demonstrates the constructive aspects of a high-current laboratory for measuring incident energy in different conditions of moisture and temperature. Thus, the paper discusses about the limitations of the laboratory’s voltage, current and arcing time, as well as its main equipment, methods to arc ignition and a methodology to measure the resulting incident energy through calorimeters and a thermographic camera . With the laboratory’s conclusion, it is intended to contribute with the existing methodologies for testing arc flash in laboratory and the respective measurement of incident energy, as well as to provide results that can collaborate with more accurate sizing of personal protective equipment in several weather conditions.

Reconfiguração de Redes de Distribuição de Energia Elétrica com Geração Fotovoltaica Utilizando FPA

Yanick R. Gomes — 2022-11-30

This article presents an approach based on the Flower Pollination Algorithm to solve the radial distribution network reconfiguration problem considering photovoltaic systems. The objective function minimizes the energy losses in the network. Four different cases are presented to analyze the impact of network reconfiguration and photovoltaic systems on the objective function of the problem.The tests are carried out through a distribution system of 33 nodes and 37 lines, considering an average load curve provided by a local distributor and a photovoltaic system connected to a medium voltage consumer located in Santo Andr´e. The results show a reduction of up to 35% of energy losses using the proposed approach, which indicates a technique that is efficient, robust and suitable for large systems. approach..

Medidas de gestão de energia em uma edificação publica: metodologia e estudo de caso

Noelma S. Maciel — 2022-11-30

Electrical energy is an essential resource for modern society. Its reasonable and wise utilization are crucial for the planet sustainable development. In this way, the environmental awareness is changing the electricity utilization and the adoption of energy efficiency measures in many sectors. This work presents a methodology for electricity bill optimization in a scholar building and a case study for technical and economic analysis of this method. The proposals are tariff contract optimization, transformers adequacy, photovoltaic power plant installation and diesel generator set utilization during peak hours. The results demonstrate 44.9% savings by the application of the proposed methodology for this building.

Minimização dos Custos de Operação de um Veículo Elétrico com Capacidade V2G

Macklyster Lãnucy S. S. de Lacerda — 2022-11-30

Electric vehicles (EV) have several advantages over traditional internal combustion vehicles, either for environmental or performance reasons. However, the autonomy of these vehicles is directly associated to the use of high energy density batteries, which in turn, have limitations related to charging time, depth of discharge and the number of charge/discharge cycles. These characteristics increase the costs related to energy and battery wear. However, a planned charging/discharging management, according to the owner’s needs, has the ability to minimize the vehicle operational costs. In this article, the AMPL language is used to solve two optimization problems that aim to minimize the operational costs of an electric vehicle. A variable pricing plan called“Tempo Verde Supervalle” from the company Endesa, which operates in Spain, was used. In the elaborated problem, if it is financially advantageous, the vehicle owner can sell energy to the grid. The obtained results show that the proposed methodology can adapt to the energy purchase and sale tariffs, providing a reduction in the EV recharge price.

Impacto da Geração Eólica na Qualidade da Energia Elétrica

Stefânia de Oliveira Silva — 2022-11-30

The growing concern with the environment and with the production of sustainable energy is characterized by the increasing insertion of wind generation plants in the energy matrices of many countries. However, it is necessary to relate the technical and regulatory requirements involved in the issue of connecting wind power generation systems to existing electrical networks. With this purpose, the article aims to identify some parameters of Electric Power Quality in Wind Turbines and their impacts when aggregated in large Wind Power Plants. In addition, real impacts of the Connection of Wind Power Plants on the Quality of Energy in the Electric System are presented, under the methodology of evaluating the impact from the perspective of the National Electric System Operator - ONS, with Electric Energy Quality Measurement Campaigns. In this way, we seek to understand how regulatory agencies in the electricity sector determine that wind turbines work in a safe and controlled way.

Microrredes: o conceito através da história, incentivos e o mercado brasileiro

Renan Moreira Soares — 2022-11-30

In recent years, microgrids have been presented as a way to modernize the electrical network little by little, due to its intelligent control and its decentralized nature, which can be inserted in parts in the electrical system. Its use is capable of increasing system reliability and flexibility, boosting sustainability, among several benefits. The microgrid concept is not so recent, and has also been modernized little by little over time. Several factors influenced this evolution, either driving or stopping this process. Moments in history, as well as the development of new technologies, were important in the biography of these electrical systems. The history of microgrids, however, did not followed a linear path. In each country, its dissemination and growth followed different historical paths, mainly due to incentives and legislation on the subject or technologies linked to microgrids. This implies different obstacles and challenges in each country. In Brazil, despite the enormous potential for the application of microgrids, regulatory challenges are a major obstacle in their dissemination. Understanding how microgrids arrived at the current concept is important to understand why they are not yet widespread, being more applied in theorical works and in laboratories. This work presents the history of the microgrids, focusing on the evolution of its concept over time, incentives and regulatory and technical challenges in Brazil for the expansion of microgrids.

Projeção da difusão de sistemas fotovoltaicos em consumidores comerciais de baixa tensão considerando cenário com venda de excedente da geração

Hilquias S. E. Chiquete — 2022-11-30

The incentive of renewable sources has provided a high growth to photovoltaic energy (PV) in the electric matrix, today it is essential that planning practices are prepared to operate, monitor and propose scenarios ideas of insertion or withdrawal of policies in benefits to all agents of this chain of operation. Thus, a model is presented for projection of the diffusion of photovoltaic systems (PVS) for commercial consumers of Group B served by the voltage level below 2.3 kV. The proposed model uses the System Dynamics (SD) technique, based on Roger's theory of diffusion of innovations, together with bass's model. The model evaluates the propensity of adoption over time considering three aspects: regulatory, economic, technical and the imitation and innovation coefficients arising from the Bass model and is rotated using the Vensim software from Ventana system. Four scenarios are tested to project the diffusion of PVS to validate the proposed methodology, the results show how incentive policies can interfere in the adoption of PV technology.

COUPLED INDUCTOR RESONANT SWITCHED CAPACITOR VOLTAGE EQUALIZER FOR PHOTOVOLTAIC PARTIAL SHADING COMPENSATION

Cláudio H. G. dos Santos — 2022-11-30

Switched capacitor converters play an important role in various applications in power electronics. Voltage equalizers are one of them, and have been applied for partial shading compensation in photovoltaic systems. In other works, the switched capacitor, have been improved with the addition of a small inductor, becoming a resonant converter with many advantages compared to switched capacitor. However, this converter can still be improved in many aspects, rather in its effective resistance, equalized voltage drop, and current stress. In this paper, a novel Coupled Inductor Resonant Switched Capacitor voltage equalizer is proposed. The comparison between all circuits here studied is developed through simulation results. Also, the proposed circuit experiment results are presented. At the end, conclusions summing the paper contribution are made.

O Comportamento de uma Rede de Distribuição de Baixa Tensão Frente à Penetração da Geração Fotovoltaica e Armazenadores de Energia

Rafael Martins Leite — 2022-11-30

Brazil has great potential for generating energy through renewable resources, es- pecially from sunlight. By providing a substantial profit, both for their sellers and users, photovoltaic generators are increasingly present in low voltage distribution networks. However, its excessive incorporation into the electrical system may cause problems related to the electrical power quality, such as voltage deviation, phase unbalance and increased technical losses. Consid- ering the continuous expansion of small photovoltaic generators presence on the grid, this paper aims to avoid possible disturbances, without compromising the integration of this technology into the electrical system, making it possible to take advantage of distributed generation’s full potential. Therefore, the use of energy storage systems is proposed. For comparison purposes, simulations were carried out considering storage devices connected in a distributed way, together with the PV systems or just a concentrated unit in the first bus of the studied network. Both configurations presented improvements in voltage levels, reduced losses and increased the grid’s ability to consume the generated energy locally, reducing the power exported to the medium voltage primary grid. However, it is observed that, due to its characteristic operation, the concentrated storage may worsen the unbalance percentage level.

Estudo da Conexão de um Filtro Híbrido Série em uma Microrrede Ilhada com Filtro Ativo em Série com a Rede

Hélio M. A. Antunes — 2022-11-30

The electric power sector due to the great expansion of distributed generation has been undergoing many transformations. Within this context a new concept is being widely discussed: the microgrid. A microgrid is formed by a set of electrical loads, generation sources and energy storage elements, and can operate in grid-connected and islanded mode. However, in islanded mode a microgrid has a low short-circuit power, due to the presence of distributed generators formed by electronic converters, which can make the network susceptible to Power Quality (PQ) problems. In this paper is evaluated by means of simulations the operation of a series hybrid filter in AC microgrid that operate in islanded mode. The main results show that the proposed filter is effective for improving the PQ, with an active filter nominal power equal to 6.64% of the microgrid load.

Estimação de Estados de Redes de Distribuição Desequilibradas Através do Algoritmo E-OPF

Ana F.P. da Costa — 2022-11-30

This work presents a computational tool for State Estimation of single-phase, two- phase or three-phase electricity distribution networks. The proposed methodology considers the unbalanced network and applies the optimization algorithm for state estimation (E-OPF) from literature. Active and reactive power loads are treated as extended variables in the optimization model and are constrained by limits obtained from the system data. The objective function combines the state estimation error of the well-known Weighted Least Squares (WLS) approach with additional indexes related to state variables, which improve the state estimation process. To verify the effectiveness of the proposed technique, the simulations are performed using a 33-bus system modified to include imbalances usually found in the electrical distribution networks.

Previsão de Carga de Curto Prazo para grandes áreas geográficas considerando ponderação por Região Meteorológica

I. C. Figueiró — 2022-11-30

This paper presents a short-term multiregional forecasting approach for macro-regions, with the main contribution being the proposal of an indicator that represents the Average Consumption per Meteorological Region (CERM), to be used as weighting of each EM as their importance for the total demand of the macro-region. In addition, the Variation of Load and Temperature index (IVCT) is proposed, based on the historical variation of temperature and demand This indicator is incorporated into a model of neural network of the Multi-layer perceptron type (MLP) for the load forecasting on the horizon of 7 days ahead with hourly and daily discretization. The results showed higher average performance of the variable IVCT in relation to the other combinations performed, and the best results were used to compose the prediction of the MTR. Finally, the proposed model presented a MAPE (Mean Absolute Percentage Error) lower than 1%, presenting superior performance compared to an basis aggregate model for MTR, which shows the efficiency of the proposed methodology.

Modelo de análise econômico-financeira das distribuidoras de energia elétrica na ótica da geração distribuída

Carmen B. Rosa — 2022-11-30

There is scientific evidence that consumers have a growing motivation to move towards a distributed generation of electricity, but the power distribution companies expressing considerable concern about the impact of increasing penetration rates of distributed generation on their revenues. In this sense, this study presents analyzes and laboratory simulations based on a business model that encourages the sale of surplus generation. The power flow simulations in the feeders include a storage agent, which negotiates the purchase of surpluses and provides ancillary services to the utility. With these data, the economic- financial analysis was proposed, contemplating the discounted cash flow and comparing the different scenarios. The study identified competitive scenarios from the point of view of the concessionaire's market value when considering the payment of the TUSD by the prosumer and the storage agent. Furthermore, it showed that in both experiments with residential and commercial consumption classes, the sale of surplus energy would bring greater attractiveness that would result in a greater number of prosumers with photovoltaic distributed system, thus evidencing equity in the economic sustainability of micro and mini generation distributed, consumer and distributor agents.

Desenvolvimento de Modelo Virtual de Religador para Redes de Distribuição de Energia para uso em Simulação Hardware-in-the-Loop

Isabella B. Pereira — 2022-11-30

This paper aim to model a distribution recloser in order to use it in real time digital simulations studies. The importance of automatic reclosers is pointed out due to its ability to clear temporary faults and ensure selectivity for permanent faults. To run the real time simulation, the hardware-in-the-loop methodology is used, which is designed using Typhoon HIL Inc. software and hardware tools. The model is developed based on the performance of real reclosers, involving all its operation settings. To validate the proposed model, it is inserted in a test system, having its behavior evaluated when submitted to several types of faults. The model has correctly operated for all faults, either temporary or permanent. Also, the recloser operating times are within the limits set by distribution systems protection standards.

Impacto da alteração da curva de carga na expansão do sistema elétrico brasileiro

Rachel da Costa O. Santos — 2022-11-30

New challenges are arising not only because of the decentralization of the national electric system, but also due to the intermittence of alternative energy sources. These challenges require advanced forms of control and monitoring of the demand curve. In this context demand side management (DSM) is one of the main areas for future investments in Brazil. In view of this, this article emerges as a study of the impact of DSM on the expansion of the National Interconnected System (NIS) in 2040. This article simulates three scenarios in CARTHER, an academic software which optimizes the costs of expansion planning for long term. The first scenario does not have any alteration in the typical demand curve, in other words this scenario will be considered the baseline one. The second scenario assumes the modification of the load profile of residential consumers due to the popularization of time of use tariffs in 2040. Lastly, the third scenario assesses possible changes in the typical load curve of each subsystem, considering the implementation of more generic DSM measurements, for example time of use tariff, in the residential, industrial and commercial sectors in 2040.Not only differences could be observed in the increment of the total cost of these investments, but also subtle changes were perceived in the composition of the electrical matrix for the three scenarios evaluated. This article contributes concluding that the load profile directly influences the expansion of the NIS, being possible to shape it so that it has an electrical matrix more reliable and with more renewable energy resources.

Metodologia para Alocação Ótima de Para-raios em Linhas de Transmissão

Matheus Christino Marzochi — 2022-11-30

The application of transmission line surge arresters (TLSAs) is one of the main approaches found to boost the performance of overhead transmission lines (OHTLs) against atmospheric discharges. Thus, this work proposes a methodology for the optimal placement of TLSAs in OHTLs based on the combination of an optimization algorithm - inspired by General Variable Neighbourhood Search and Genetic Algorithm - and the ATP (Alternative Transient Program). The line performance estimation is made considering the little cited transfer effect of the atmospheric surge due to arresters operation. At the end, in order to analyze the functioning of the proposed procedure, experiments are carried out to optimize the positioning of TLSAs in two OHTLs. It may be inferred from the results that directing search considering the lightning surge transfer effect and favoring the positioning of TLSAs in the lowest phase(s) can reduce the amount of arresters necessary to satisfy the performance constraints, or at least diminish the application computational cost.

Modelagem de uma linha de transmissão com trecho aéreo, subterrâneo e subaquático para o estudo de desequilíbrio de tensão

R. T .M MANSUR — 2022-11-30

This article presents the modeling of a transmission line with overhead, underground and underwater sections for the study of voltage unbalance for the predicted maximum load scenarios. The evaluation of voltage unbalance at the design stage is an important preventive action not only for the reduction of electrical losses, but also for the mitigation of power quality phenomena and operational interference in transmission lines. After an initial discussion about voltage unbalance, its consequences and how to determine it, the modeling by the ATPDRAW software is presented to evaluate the negative and zero sequence voltage unbalances. The objective is to define the parameters of this system for simulating voltage unbalance compared to the maximum allowed limit of 1.5%, established by the ONS for the condition of the transmission line to operate at no load and at full load. The results obtained show that the proposed aerial, underwater and underground transmission line is capable of operating within the unbalance limits established by ANEEL. However, it was observed that a possible increase on the extent of the future LT will directly affect the maximum calculations.

Metodologia para Estimar a Vida Útil de Para-raios de Óxido de Zinco Baseada na Aplicação do Sistema Neuro-Fuzzy Adaptativo

Vandilson R. N. Barbosa — 2022-11-30

This work presents a methodology to be used to estimate the Metal Oxide Surge Arresters’ (MOSAs’) useful life, based on the prediction model based on the Adaptive Neuro-Fuzzy Inference System (ANFIS). For this purpose, a database consisting of MOSA’s total leakage current was used. Thus, it was possible to build a time series composed of values of the third harmonic component of the leakage current. This component is one of the indicators of the MOSAs’ degradation level most used in the surge arresters monitoring. Subsequently, the forecasting models based on artificial intelligence (ANFIS and Support Vector Regression - SVR) were implemented, evaluated, and compared. During implementations, the ANFIS model was tested with three distinct membership functions: Gaussian, Generalized Bell-Shaped, and Pi-Shaped; and the SVR model was tested with three different kernel functions: Gaussian, Linear, and Polynomial. The performance of each implemented model was evaluated using the determination coefficient in the training phase of the models and the mean absolute percentage error, in the validation phase. Considering the results obtained by the ANFIS e SVR models, it was found that the forecasts made using the ANFIS model with Gaussian membership function were the most accurate forecasts. Thus, the proposed methodology, which applies the ANFIS model with Gaussian function, was used to estimate the MOSA’s useful life.

Inversor Flying Capacitor com indutores acoplados operando em modo Grid Following

André Pacheco Meurer — 2022-11-30

Este artigo apresenta a modelagem e controle de um inversor Flying Capacitor operando em modo Grid Following. O trabalho demostra a modelagem da malha do PLL, da malha externa para a regulagem de tensão do capacitor do barramento, as malhas externas de potência ativa e reativa bem como a malha interna de controle de corrente em coordenadas estacionárias. Para conesão com a rede, foi utilizado um filtro LCL com amortecimento passivo. Cada fase do inversor contém dois bracos com interruptores em paralelo e operando em phase shift com objetivo de diminuir os esforços de comutação nos IGBTs. A fim de dividir a corrente entre os braços do inversor, malhas de controle de corrente circulante e malhas de controle de tensão dos capacitores flutuantes foram implementadas. Os resultados de simulação demonstram que a topologia proposta é uma candidata a ser utilizada para integração de fontes primérias de energia com a rede de distribuição.

Topologia de Conversor MPPT de Estágio Único Baseado no Conversor de Célula Flutuante

Guilherme David Muller — 2022-11-30

This article introduces a floating capacitor single stage DC-AC inverter inspired in the flying capacitor multilevel cell. A basic structure for the MPPT was elaborated applying incremental conductance algorithm acting in the phase angle of the sinusoidal PWM reference. The control strategy was simulated in the MATLAB/Simulink software for a 6.3 kWp photovoltaic panel and results have validate the converter proposition with harmonic current levels of acceptable inverting harmonic levels.

Algoritmo PSO com Voos de Lévy para Alocação e Dimensionamento de Geração Distribuída

Diego José da Silva — 2022-11-30

Distributed generation (DG) offers several benefits to the electrical system, such as the reduction of losses and improvement of the voltage profile. DG benefits can be maximized when allocation and sizing are optimal — a problem known as the Optimal Sizing and Placement of Distributed Generation (OSPDG). This paper presents a new meta-heuristic that associates PSO (Particle Swarm Optimization) with L´evy flights (LF) to solve the OSPDG, identified in this work as LFPSO. The tests carried out on the 69-bus distribution system indicate that the LFPSO is superior to the PSO in relation to the convergence process. The results obtained considering the allocation of up to three DG point to a reduction of 98.1 % in active power losses.

Desafios e Soluções na Proteção de Linhas de Transmissão Conectando Fontes de Energia Não Convencionais

Marcelo Bini — 2022-11-30

This paper discusses the impact of inverter-based resources (IBRs) in traditional digital protection relays applied in the interconnection transmission line between the IBR and bulk power system. Real events involving a photovoltaic (PV) power plant are used to show the behavior of the fault currents, which is different from power systems with synchronous generators, especially for negative- sequence components. The paper discusses how to properly handle this kind of source by presenting modern protective relays features, time-domain functions, and special settings for traditional protection intelligent electronic devices (IEDs).

Máxima capacidade de hospedagem de geração distribuída considerando um modelo de otimização usando o método de injeção de correntes

Glauber D. S. do Vale — 2022-11-30

This article presents a novel deterministic methodology to determine the maximum distributed generation capacity in power distribution systems. In the proposed approach, an optimization problem is formulated to calculate the maximum amount of power to be accommodated in a power system without violating operational limits. For the proposed formulation, the current injection method equations are considered as equality constraints to compute the power flow solution. Maximum and mnimum limits for the voltage magnitudes are considered as inequality constraints, as well as the powers at each busbar and the reverse power flow at the utility substation. The optimization problem is solved via interior-point method. Aditionally, in order to account for uncertainties, the system loads are modeled using Gaussian probability density functions considering a statistical dipersion with respect to their nominal values. Computational simulations are conducted using a 23-bus distribution system. Several analysis are carried out, considering the generation units allocated dispersely in the grid to be evaluated, proving the efficiency and versatility of the proposed method.

Análise Eletromagnética de Motor de Fluxo Axial com Sistema de Excitação Misto com Enfoque em Tração Elétrica

Ricardo Corinaldesi Cardoso — 2022-11-30

The main objective of this work focuses on an electromagnetic analysis of an axial flux topology machine with mixed excitation system to meet the requirements of an electric traction system, whose speed ratio in the field weakening region is 1:2. The methodology employed consists in the elaboration of a magnetic equivalent circuit and the subsequent simulation of the device using the Finite Element Method via numerical solving software.

Comparação dos níveis de THD entre turbinas DFIG e PMSG na integração de usinas eólicas em situações de falta

Phillipe L. S. Santana — 2022-11-30

In this paper, a comparative analysis of Total Harmonic Distortion (THD) between wind farms with double-fed induction generators (DFIG) and synchronous permanent magnet generators (PMSG) integrated into the grid is developed. The Fast Fourier Transform (FFT) technique to evaluate the output current signal THD in different fault conditions and indicate the best performance among the generators is used. Harmonic generation problems are associated with wind generation, due to the non-linear characteristics of its converters and non-linear loads connected to the grid side. The integration of two 10 MW wind farms with five 2 MW wind turbines is analyzed, using DFIG and PMSG turbines, operating in different fault occurrence scenarios, connected to 25 kV and 120 kV at 60 Hz systems The results show that the PMSG presents better performance, with low THD, compared to the DFIG, for the analyzed cases.

Avaliação Quantitativa e Qualitativa da Flexibilidade na Interface entre Sistemas de Transmissão e Distribuição

Ranielli V. Pombo — 2022-11-30

The growing scenario of Distributed Energy Resources (DERs) integration in low voltage brings challenges related to the security operation of power systems globally and possibilities of providing ancillary services to contribute to system management. Therefore, the power exchange at the interface between the transmission and distribution systems gains relevance for the security operation of both. In this context, the flexibility region emerges as an alternative to enable the knowledge of this information, and the flexibility coefficients present themselves as a possibility to measure the capability of each system from the point of view of both operators. This work applies a methodology to construct flexibility regions and the concepts of flexibility coefficients to evaluate the connection of transmission and distribution systems. The reference methodology was expanded to handle the construction of maps for the transmission system through a few modifications in the problem formulation. Simulations and analysis were executed using 33 and 38-bus transmission and distribution systems through Python language implementation. The results show that the flexibility coefficients allow performing analyses to identify the best connection point between systems to take better advantage of their flexibilities.

Simulador de Controle de Tensão Área Goiás/Brasília Utilizando Algoritmo Genético de Chu-Beasley

Rubens Batista Pereira — 2022-11-30

The constant expansion process of the National Interconnected System (SIN), originated by the socioeconomic development of Brazil, provides dynamism to the mode of operation of the electric power transmission system, so that solutions implemented in the past may have their effectiveness diminished over time due to changes in the energy scenario. Of the consequences caused by these changes, the dip in the voltage profile in buses bordering the electricity distribution system stands out. The voltage control carried out by the SIN operation centers aims to maintain the voltage at acceptable levels at all times in the system. The effectiveness of voltage control during disturbances in the electrical system or in severe load conditions is strongly associated with the sectorial reactive support capacity. The voltage control simulator in the Goiás/Brasília area allows an analysis with emphasis on the effects generated by the maneuverable voltage control shunt equipment – reactors and capacitors – in the system. Through the Chu-Beasley genetic algorithm, the simulator is able to suggest the optimized configuration of the elements so that the bars operate with tension equal to or very close to 1 pu. The performance of simulations allows the previous verification of the effectiveness of the maneuvers to control the desired voltage in the integrated operation with the other equipment of the SIN.

Estudo de Caso de Redução de Perdas de Energia por Vazamentos Provocados por Excesso de Corrosão e Temperaturas Elevadas no Sistema de Ar Comprimido de uma Fábrica de Biscoitos em Serra Espírito Santo

Osiel S. Luiz — 2022-11-30

Faced with the growing increase in industrial activity, cost reduction becomes a preponderant factor, given the fierce competition in this sector. In this context, the reduction of energy costs appears as a strong ally in the search for more efficient means of production from an economic and environmental point of view. This study shows that it is possible to obtain excellent results by implementing methodologies to control losses caused by leakage and temperature. Although the main objective of the implementations is to increase productivity, reduce energy and operational costs, the reduction of energy losses also contributes significantly to the environment, allowing a better use of available resources. The study was carried out in a small biscuit factory, located in the municipality of Serra-ES, with the objective of presenting a technical, economic and environmental feasibility study to reduce energy losses in the compressed air system, considering which company uses large-scale pneumatic equipment, driven by air compressors. Maintenance reports pointed out that in the last three years, there have been consecutive increases in maintenance costs resulting from leaks, arising from the corrosion process, generating numerous unscheduled stops in production in the compressed air system. Based on this information, it was proposed to replace the pipe with a new one, so as not to stop production during the execution of the project. It was also proposed to use anti-corrosion protection to increase the useful life of the new pipeline. These measures proved to be quite effective, allowing a reduction of R$ 9,566.53 per year in electricity. An increase in efficiency was also sought after, by reducing the temperature of the air admitted by the compressor, since the excess energy consumed by the equipment, due to the high temperatures inside the engine room, in relation to the external environment generates an extra energy cost of BRL 3,148.98 per year.

Análise da Qualidade do Fornecimento de Energia Elétrica Através do Uso de Sistemas Multiagentes

Juliano S. Damiani — 2022-11-30

Multi-Agent Systems (SMA) are seen by the electricity sector as a tool for solving the problems faced by utilities. Therefore, a study was developed to evaluate the power quality supplied to the consumer. This article aims to show how SMA can improve utilities’ quality indexes and consumer satisfaction, overcoming the problem of delay in obtaining voltage data and the correct classification of possible disturbances. To achieve this goal, the authors considered the use of SMA as a means of communication between smart meters. The purpose of using smart meters is to utilize devices inserted in smart grids, mainly due to reading data and using artificial intelligence techniques. The proposed method was implemented in Java Agent Development Framework (JADE), and the data used for evaluation were obtained through an energy analyzer installed in three homes. The results of the simulations show that this SMA provides speed, efficiency, and automation for the process of power quality supplied by the utility.

Avaliação do Desempenho da Proteção de Distância Utilizando o Barramento de Processos

Paulo Henrique Pinheiro — 2022-11-30

The presence of telecommunications and intelligent devices is increasing in electrical systems. With the IEC 61850 standard, the topology of electrical substations is being modified to the known digital substations. These substations are divided into process, bay, and station levels. With this new topology, there is a need for detailed studies about the behavior of protection, control, and supervising functions to analyze if these functions will not lose performance. Protection functions impose significant challenges with the implementation of the process bus. Important evaluation points are the correct operation of these functions, acting time and fault clearing times, and behavior during process bus contingencies. This paper analyzes the dynamic performance of distance protection using the process bus. The main evaluated points are its acting time, fault clearing times, and performance during process bus contingencies. The results show that the use of the process bus presents an error of 1,96 % compared to the conventional topology in the fault clearing time. In the cases considering concurrent traffic in the process bus, the maximum error is 2,38 %, thus concluding that the process bus does not significantly influence the protection performance.

Desenvolvimento de um modelo de clusterização de usinas eólicas para atendimento dos modelos de previsão do ONS

Paulo Sérgio de Castro Nascimento — 2022-11-30

The present work proposes to obtain a clustering of wind farms using the Gaussian Mixture Models (GMM) method, based on the wind profile and geographic location of wind farms operating in the South and Northeast regions from Brazil. The purpose of the generated grouping is to provide inputs for the wind generation forecasting models, helping the daily schedule of the operation of the National Electric System Operator (ONS). The success of this application allows the creation of generation and wind series more assertively within each cluster, thus increasing the reliability of the system operation. Thus, the main contribution of this work is to propose an alternative form of clustering, in relation to what is currently used by the ONS.

Sintonia automática de parâmetros de controladores LQR aplicados a inversores conectados à rede

Everson Mattos — 2022-11-30

In this work, an automatic controller tuning based on metaheuristics is proposed to obtain, in an optimized way, the weights of the Q and R matrices of a quadratic linear regulator applied to the control of current from converters connected to the grid. The proposed strategy allows obtaining superior performance in relation to controllers tuned traditionally, without requiring the designer to spend a lot of time in designs based on trial and error. The results show that the grid currents obtained are in accordance with the IEEE 1547 standard, indicating the usefulness of the proposed strategy for the control of power injected into the grid in distributed generation systems where the grid impedance at the point of common coupling may be affected by uncertainty.

Aplicação da Transformada de Hilbert-Huang na Localização de Faltas em Linhas de Transmissão Utilizando a Teoria das Ondas Viajantes

Andressa P. Oliveira — 2022-11-30

This paper presents an application of the Hilbert-Huang transform and the traveling wave theory for fault location in transmission lines, using data from two terminals, for a test system with a 200 km long transmission line between two voltage sources. The MATLAB/Simulink® software was used to simulate different fault conditions and analyze the voltage signals, through the programmed algorithm, to estimate the fault location. The numerical and graphical results obtained proved the efficiency and high precision in locating the fault for the methodology used, when compared to the techniques found in the literature, considering all types of faults, different fault occurrence locations and fault resistances.

Proteção Anti-Ilhamento da Geração Distribuída: análise da atuação indevida da função de subtensão devido a curtos-circuitos em alimentadores adjacentes

Jamenson Guilherme Ozelame — 2022-11-30

The significant growth in the number of connections of distributed generation (DG) units in distribution networks increases the operational complexity of such networks. One of the complicating factors is the improper action of the DG protection against islanding using an undervoltage relay in the event of short-circuits in feeders adjacent to the generation connection. In this sense, this study investigates through computer simulation in which situations this undue actuation occurs and which circuit elements influence the occurrence or not of these actuations.

Desenvolvimento de um sistema de armazenamento de energia operando em paralelo com a rede

Vitor G. Neves — 2022-11-30

The battery energy storage systems (BESS) have been gaining notoriety in recent years due to the high penetration of renewable energies in distributed generation. It has the main goal of providing a dispatchable and reliable generation source. This study details the implementation of a BESS with a bidirectional converter as the interface between the battery bank and the supply network. The converter’s modeling and control equations are presented, as well as the experimental results obtained with a 10kVA prototype. Thus, this work presents a complete characterization of a system capable of carrying out the process of Lead Acid Battery charging and discharging, energy supply and ancillary services.

Análise Crítica da Abertura do Mercado Livre de Energia Elétrica Brasileiro para Clientes de Baixa Tensão

Giovana Bortoluzzi Brondani — 2022-11-30

In a production chain, inputs must be the object of transaction, especially electricity. In the electricity market, electricity suppliers cannot currently select their electricity supplier, receiving energy sources from Brazilian electricity distributors. The market for this is to present an overview of how an opening of low-objective consumers worked and some difficulties that can be used to work with this type of liberalization in Brazil.

Detecção de Faltas de Alta Impedância Baseada em Boosting de Árvores de Decisão

Bernardo A. V. de Souza — 2022-11-30

The occurrence of high impedance faults is an event that is difficult to detect in distribution lines and may cause various hazards to the population. With the conductor falling to the ground, the fault current does not sensibilize the protection systems and can cause several accidents. Frequently, this type of fault is confused with other line events, further delaying the detection. The present work aims to insert simulated data of high impedance faults and several other events common to the network, to detect them using a boosting of decision trees, the XGBoost classifier. The obtained results demonstrate the accuracy of the 97.67% classification model.

Modelagem de recarga de veículos elétricos aplicada para agendamentos considerando parametrização de dados por OCPP

Henrique Martins — 2022-11-30

This paper presents a model for electric vehicle chargers with application in load scheduling, considering parametrization by OCPP protocol. The model seeks to find – considering information given by the user- the charging time that an electric vehicle can stay in a station, based on the battery charging model. The model uses a combination of KiBaM model with voltage model for determination of the charging time of the electric vehicle. The calibration uses real data collected by real time measuring in the chargers using the OCPP protocol. Finally, the model is applied with a framework system for scheduling of the electric vehicle use determining the charging hours and the economic and technical impact on the system. The real tests were made on an electric vehicle charging station for the COPEL - Companhia Paranaense de Energia located inside the Federal University of Santa Maria.

Análise de sensibilidade estatística dos atributos físico-elétricos no cálculo dos indicadores de continuidade de sistemas de distribuição

Robson P. Delavechia — 2022-11-30

In this paper, results related to the statistical sensitivity analysis of physical-electrical attributes in reliability index calculation of distribution systems will be presented. Considering that electricity companies are inserted in a natural monopoly, the National Agency of Electrical Energy (ANEEL) current methodology proposes a comparative assessment strategy of different sets of consumer units, to classify their performance in relation to the power quality service. From a Stepwise regression model, the statistical sensitivity of different arrays of physical-electrical attributes is assessed. The results obtained for a real case studies demonstrate the impact of regional characteristics on the performance of distribution systems.

Metodologia de Analises Elétricas Integradas de Sistemas de Distribuição e Subtransmissão usando o Software OpenDSS

Israel Panazollo — 2022-11-30

Faced with the various computational tools with their different functionalities and applications, some organizations or companies may choose to use different software. you can use OpenDSS. The work proposes a program or computational environment in which it would be possible to analyze in an integrated way these two areas of electrical networks, using Python programming.In this way, developing broader analyzes and understanding the impact of distribution networks on transmission networks and vice versa, such as power flow, losses, voltage limits, among other important values, in addition to providing a planning that would take into account these different areas.

Análise de Métodos de Agrupamento Aplicados na Definição de Limites dos Indicadores de Continuidade

Leonardo da Silveira — 2022-11-30

In the context of electricity distribution in Brazil, the National Electric Energy Agency (ANEEL) is responsible for regulating and inspecting the performance of companies. The quality of services provided by distributors is measured by indicators of continuity of supply, to which performance limits are defined using a comparative analysis methodology. The premise of this methodology is that similar sets of consumer units must have equivalent performance. Such similarity between sets is defined by attributes, which describe characteristics of the electric distribution system and the consumer market. This work analyzes the step of grouping sets of the current model used by ANEEL for calculating the limits of the DEC and FEC indicators. The limits for different case studies are calculated, in which the selected attributes, the grouping method and the adopted parameters are varied. Then, the sensitivity of variations is analyzed through the limits calculated in each case study. As main results, it was observed a greater sensitivity for variation of attributes and of the clustering method and a lower sensitivity for variation of the parameters of the dynamic method.

Previsão de Demanda de Energia Elétrica em Microgrid Considerando Níveis Menos Agregados por Meio da Aplicação de Rede Neural Artificial GRNN Combinada com o Método Estatístico SARIMA

Nelson Nunes André Junior — 2022-11-30

The growth in electricity consumption in the world forces countries to have a well-structured planning in relation to forecasting the demand for electricity in their most diverse sectors. Several techniques are used to predict electrical loads, such as artificial intelligence models, statistical models and hybrid models. This work aims to present a model based on the combination of a statistical method, SARIMA, and an artificial neural network, the GRNN, to improve the accuracy of forecasts of demand for electricity consumption. The data set used in this work belongs to a group of buildings located in the Itaipu Technological Park and was acquired through electronic meters installed together with the transformers that serve each of these buildings, performing data collection every 15 minutes. After processing and refining the database, forecasting techniques were applied, each one using a forecast horizon of 1, 3 and 5 days, the first technique being the combination between GRNN and SARIMA and the other techniques used were the methods themselves separately, allowing the comparison of their results. The results obtained with the proposed combined model are, in general, more accurate when compared to the results of the techniques individually, as they combine the advantages of each technique and end up smoothing the negative characteristics of each other, thus causing a balance that reflects on the forecast. generated.

Aplicação e Avaliação do Método da Impedância Dominante para Compartilhamento de Responsabilidade Harmônica em um Sistema Industrial

Luiz F. S. Souza — 2022-11-30

Faced with the growing use of non-linear electrical loads, which are potential sources of harmonic distortions, interest in the topic of sharing responsibility for harmonics has increased in electrical system. It is known that harmonics can generate several problems for the electrical network and for the loads connected to it, so mitigating measures, when required, should be shared between those responsible for the disturbances, in proportions correlated to the contribution of each consumer and supplier agent. In these terms, the present work aims to analyze the results of the application of the Dominant Impedance Method (MID) of harmonic responsibility sharing in a Brazilian industrial system.

Sistema Fotovoltaico Conectado à Rede com Capacidade de Compensação de Potência Reativa

José Henrique S. Carvalho — 2022-11-30

This paper presents the development of a photovoltaic system that, in addition to generating active power, is capable of compensating the reactive power at the point of common coupling (PCC). The system consists of photovoltaic modules, a dc-dc converter, a three-phase inverter and an output L filter. The output filter dimensioning and the controller design with the aid of the dq0 transformation are presented. The system was validated through computer simulations in PSIM software. The simulations showed that the system is capable of performing active power transfer and reactive compensation, injecting current with low harmonic content into the PCC.

Análise do impacto da velocidade do vento no fluxo de carga em um sistema elétrico de potência

Marcos F. Silva — 2022-11-30

In this paper the impact of wind speed variability in a wind farm on the load flow is analyzed . For this analysis, a DFIG wind turbine is mathematically modeled in a polynomial that represents the power injections, as a function of wind speed, and the Weibull probability (FDPW) for generating random values for wind speed. The wind farm used consists of 125 wind turbines of 2 MW each. The computer simulations are performed in the New England 39 bus system. The load flow problem is solved by the Newton-Raphson method for each wind speed generated by the FDPW. The results show a significant impact of the variability of wind speed on the load flow, with a tendency to oscillate and change the power flow in the lines to supply the low wind generation and/or reactive demand of the farm.

Avaliação técnica de métodos para detecção de perdas não-técnicas em sistemas de distribuição de energia elétrica

Fernando G. K. Guarda — 2022-11-30

In this paper, a technical analysis of the main methods used to detect non-technical losses in energy distribution systems will be presented. Non-technical losses are the main source of revenue loss for energy utilities, causing not only financial losses, but also damaging the quality of service for these companies. Methods for detecting non-technical losses are divided into three groups: Data oriented methods; Network Oriented Methods and Hybrid Methods. The performance of methods from each of these groups will be evaluated, showing that data oriented methods need additional installed equipment, and future trends are hybrid methods, artificial intelligence and data science.

Aplicação de Inversores Multiníveis para Redução do Conteúdo Harmônico das Correntes de uma Máquina PMSM N˜ao-Senoidal

Lucas Rossato Rocha — 2022-11-30

This work presents the use of multilevel inverters in a non-sinusoidal permanent magnet synchronous machine to reduce the harmonic content in the currents. Due to the con- struction of this machine, the back electromotive force presents a non-sinusoidal characteristic, which has as main consequence the presence of ripple in the electromagnetic torque produced by the machine. Such oscillations decrease the efficiency of the machine, and can cause vibrations in the motor shaft, reducing its useful life. To mitigate this, this work uses multilevel inverters with flying capacitors to synthesize voltages with 3, 5, 7 and 9 levels, in order to reduce the harmonic content of the stator currents, and consequently the machine torque. Qualitative analyzes are presented through the total harmonic distortion and ripple in the machine currents, and the weighted total harmonic distortion of the inverter output voltages, comparing the performance of multilevel inverters with a half-bridge inverter of 2 levels.

Battery Energy Storage System to Support Voltage in Distribution System with High PV Penetration

Lílian V. Pinheiro — 2022-11-30

This work performs a sensitivity analysis regarding the control of Battery Energy Storage System. (BESS) for the regulation of voltage levels in a distribution system with high photovoltaic penetration. In the evaluated methodology, the BESS system is connected to a bidirectional DC/DC converter in current, through which it is possible to define the power to be absorbed or injected by the battery. By adjusting this reference power, it is possible to control the voltage profile of the network, and this adjustment is defined from reference curves that take into account the system's strategic voltage readings. By varying the parameters of the reference curve, the impact on battery power and, consequently, on the voltage profile of the system is evaluated, drawing a sensitivity of the voltage profile with the control reference curve. To test this methodology, a simulation environment was created via Simulink/Matlab, modeling the Cigré 18- Bus test system, to which photovoltaic generation points and the BESS system were added. Then, the system was submitted to real load and solar irradiation curves, and the performance of the BESS and the behavior of the voltage in the network were evaluated.

Medição de Emissões Acústicas Provenientes de Descargas Parciais em Sistema Ponta-Plano e Correlação com o Método Elétrico

André M. de Morais — 2022-11-30

The evaluation of the operating condition of medium and high voltage equipment based on diagnosis of Partial Discharges (PDs), obtained from the measurement of ultrasonic acoustic emissions, has been the object of analysis of many works available in the technical literature. In this sense, this work presents a practical investigation of the occurrence of PDs, detected through acoustic and electrical methods, in a point-flat system subjected to different voltage levels, gaps and environmental conditions. This methodology is adopted to correlate the measured data with the acoustic (unconventional) and electrical (conventional) methods, in order to demonstrate the effectiveness of the former and contribute to obtaining diagnoses with high precision and reliability. The occurrence of PDs signatures, in the time domain for the acoustic and electrical methods, were obtained for the scenarios under analysis, both indicating, with good approximation, the incidence of the phenomenon. The analysis in the frequency domain of the results acquired with the acoustic method also corroborated the diagnosis of PDs in the evaluated scenarios.

Participação da geração eólica no controle carga-frequência de sistemas hidro-eólicos através do gerador síncrono virtual

Gabriel Schreider da Silva — 2022-11-30

This paper discusses the inclusion of wind generation in load-frequency control (LFC) of a hydro-wind power system through the control technique known as virtual synchronous generator (VSG), which makes static power converters, which connect the wind farms to the grid, emulate the behavior of a real synchronous generator. In addition, wind generation is considered to operate in unloaded mode, having generation reserve to deal with system load disturbances. It was found that with the participation of wind generation in the LFC, there is a significant reduction in the frequency deviation and in the inverse response of the hydraulic plant, proving the importance of the participation of wind plants in the LFC.

Modelagem e Análise de Estações de Recarga Rápida considerando uma estrutura de Microrredes e Padrões Estocásticos

Matheus S. da Cruz — 2022-11-30

One of the actions to reduce Greenhouse Emissions is the decarbonization of the transport sector. Among the alternatives for it, there are Electric Vehicles (EV). However, to increase the EV penetration, mainly in large countries, like Brazil or the US, it is necessary the development of Public Charging Infrastructure, such as Fast-Charging Stations (FCS) on Highways, to handle long-distance trips without long-charging times. The high powers that FCSs demands encourage the use of distributed resources, such as Photovoltaic and Wind Power, and Energy Storage Systems, characterizing microgrids. However, the random nature of the elements that make up the microgrids is a challenge for the characterization of load profiles that demonstrate the temporal behavior of FCS. In this context, this article presents a methodology for modeling FCS, considering stochastic models to characterize the load profiles of these microgrids, allowing for the expansion of the scenario numbers, which makes the analysis more comprehensive. From the models obtained, the need for models that consider stochastic patterns for expansion planning is evident.

Metodologia para Linearização do Painel Fotovoltaico através do método de Thévenin e Aplicação de Álgebra Linear

Rodrigo D. Nascimento — 2022-11-30

In photovoltaic energy systems, both photovoltaic panels and switching converters have non- linear and time-variant characteristics, which results in a complex control, resulting in a more accessible methodology for performing the calculation. This paper aims to contribute with a methodology for obtaining the linearization of photovoltaic panels in series and parallel, presenting new linearization models for more than one photovoltaic panel and opening a discussion on current proposed models. The main objective is to present the modeling of the photovoltaic panel and the linearizations referring to the set of proposed panels. The validation of these models will be carried out through graphical analysis performed by the Matlab/SIMULINK software, considering the linearization of the series, parallel and mixed circuit.

Estimação dos Níveis de Energia Incidente em Transformador de Distribuição para Definição de Estratégias de Proteção Térmica ao Trabalhador

Marina Camponogara — 2022-11-30

The electric arc can reach temperatures above 20,000 ºC and, therefore, the thermal risk is considered the most representative risk of this type of event. The energy released by the electric arc, called incident energy, measures arc’s severity and it is used to define the thermal protection strategies applicable to the worker who performs activities in this type of scenario. The present work presents the process to define personal protection strategies against electric arc’s thermal effects from the estimation of the incident energy levels in a distribution transformer. The incident energy estimation is based on the mathematical model proposed by the IEEE Std 1584-2018 and the definition of garments and PPE is based on the guidelines provided by NFPA 70E-2021.

Desempenho das funções de controle de inversores inteligentes de sistemas fotovoltaicos na regulação de tensão do sistema de distribuição

Brian Jaramillo-Leon — 2022-11-30

Currently, there is a rapid growth in the installation of photovoltaic solar systems in power distribution systems. The functionalities of smart inverters can bring benefits in the operational performance of the network. In this work, the influence of the smart inverters control functions: fixed power factor; Volt-VAr; and Volt-Watt, is evaluated in the voltage regulation of the network, assuming various operating scenarios. For this, power flows are simulated considering quasi-static time-series that incorporate the dynamic behavior of the distribution system. The simulations and analyzes are carried out in a real distribution feeder of an Ecuadorian utility. The results show that under simulated test conditions, the inverter’s Volt-VAr control presents better results in supporting voltage regulation.

Análise de algoritmos de agrupamento aplicados aos problemas de reconfiguração de rede de distribuição

Thiago Eliandro de Oliveira Gomes — 2022-11-30

In order to seek alternatives to accelerate the solution process in a reconfiguration problem, this article uses the notions of graph theory to propose the exploration of different techniques oriented to the topological decomposition of a distribution system and the search for paths with lower cost. The methodological process is divided into the presentation of algorithms for topological reduction, followed by the presentation of alternatives to the search for shortest paths. The results showed better performance for the decomposition performed by the Malgrange algorithm, bringing brevity to the process and similarity between the results of the short path search algorithms.

Impactos de Geração Distribuída e Armazenagem de Energia na Rede de um Campus Universitário

Lucas Saraiva Teixeira — 2022-11-30

This paper analyses the effects of Distributed Generation and Energy Storage on the distribution grid of a university campus, in particular the effects on power flow and voltage profile as a function of distance. The original grid is formed by three distinct distribution feeders and contains 50 distinct loads. The plan is to introduce distributed generation with 500kWp of photovoltaic generation and 455kW from natural gas micro-turbines, as well as an energy storage system with nominal capacity of 1000kW/3000kWh. The program used to model and simulate this grid was OpenDSS, using data made available by the local utilities company and the university itself.

Predição de Indicadores de Qualidade de Energia Utilizando Técnicas de Processamento de Dados e Redes Neurais

Bruno Mattedi — 2022-11-30

In Brazil, one way to evaluate the service performance of electric power distribution utility is through the monitoring of electricity indices of Power Quality: SAIDI (System Average Interruption Duration Index) and SAIFI (System Average Interruption Frequency Index). They are regulated by the Brazilian National Electric Energy Agency (ANEEL), which is responsible for the application of financial penalties in case of non-compliance with regulatory limits. The estimation of these indicators provides insight into the future outlook of the company, enabling the identification of areas that have a tendency to worsen quality over time. In this work, we present a methodology for forecasting both indicators using data preprocessing, recurrent neural networks, and LSTM networks. This article uses real data from an electric utility and aims to estimate the daily SAIDI and SAIFI indicators. The results indicated that there was an improvement in the forecasting of the SAIFI, but there was no apparent benefit for the SAIDI. However, improvement in prediction allows a more appropriate allocation of maintenance teams.

Capacidade de Hospedagem de Sistemas Fotovoltaicos em Redes de Distribuição

Ronnielli Chagas de Oliveira — 2022-11-30

Photovoltaic systems are increasingly integrated with the low voltage (LV) and medium voltage (MV) distribution network. This situation has already started to produce significant challenges for the distribution system operators due to the energy quality impacts associated with their integration with the network, such as increases in voltage levels, harmonics, intermittence, bidirectional power flow and frequency variations . In this context, Hosting Capacity (HC) studies focused on distribution systems are increasingly relevant. Aiming to contribute with studies related to this area, this work presents a methodology for obtaining HC in distribution systems using the open source software OpenDSS. A study will be carried out for different scenarios of a test distribution system provided by the IEEE, the IEEE European Low Voltage Test Feeder (STDE-IEEE).

Aplicação Prática da Ferramenta T-F Map na Separação de Descargas Parciais em Máquinas Rotativas e Cabos de Média Tensão

J. P. Villibor — 2022-11-30

This work aims to encourage the application of partial discharge measurements in electrical equipment in Brazil through the practical utilization of the T-F Map (Time-Frequency Map) tool, applied in the separation of multiple sources of partial discharge. Partial discharge measurements were performed on rotating machines and medium voltage cables. The measurements on rotating machines were made with a stator and a 5000 hp three-phase induction motor, while the measurements on the medium voltage cable were carried out during an artificial aging process. The PRPD (Phase Resolved Partial Discharge) patterns obtained with their respective T-F Map are shown in the article, highlighting the potential of the T-F Map utilization, whether during the development of new equipment or in the evaluation of the equipment insulation in the field.

Desenvolvimento de um Gateway OPC para aplicações de Automação no Sistemas Elétrico de Potência

Gabriel Teixeira Zanchin — 2022-11-30

The advancement of communication network technologies in recent years has enabled the emergence of a large number of protocols and equipment that require the use of intermediary hardware to integrate the nodes of a plant or automation system. The need to adapt networks to the modern scenario, perform the interoperability of these networks, and make them communicate in a transparent way is a great challenge. With the establishment of the Industrial Internet and Internet of Things, it is possible to implement solutions to solve this problem. In this context, this work was to develop an OPC Gateway for automation, capable of reading and writing values from a plant or automation systems and making them available for user access through client software. The hardware operation will be described based on the message exchange tests carried out at the end of the research, demonstrating its efficiency and usefulness.

Analysis of Leakage Current on Polluted Polymeric Insulator Using Finite Element Method

Reinaldo Corrêa Leite — 2022-11-30

This paper develops a Finite Element Model (FEM) for a 138 kV High Temperature Vulcanized (HTV) Silicone Rubber (SiR) transmission insulator in which, in a first step, leakage current is calculated for different non-uniform continuous and discontinuous pollution deposits and then features based on the phase shift between the leakage current and the applied voltage are extracted for each kind of pollution layer to identify the existence of dry bands on the insulator surface. A phase shift of 84.75° lag between the leakage current and applied voltage was found for a pollution layer with dry bands inserted. This results evidence that the phase angle can be used to detect the dry band formation by measuring the leakage current and its phase angle.

Comparação entre Controles Clássicos e Preditivo no desempenho de um Conversor Dual Active Bridge

Adriano F. Nardoto — 2022-11-30

The Dual Active Bridge (DAB) convert stands out for the application on modern power grids with DC stages. Among DAB advantages, one can cite: it has galvanic isolation between converting input and output; it presents high efficiency; it enables bidirectional power flow; it shows high power density; and it can work as buck or boost. In this paper, initially two mathematical models are discussed: small- signal modeling and discrete modeling. The small-signal modeling shows better accuracy for the operation nearly the DAB rated power. The discrete modeling presents good performance for the whole range of operation. Besides that, the paper presents and discusses three control proposals: A closed-loop voltage control using PI; A closed-loop voltage control with phase-shift prediction; and a model predictive control (MPC). The strategies were evaluated observing parameters like dynamic response, steady state behavior, and transient overshoot strategies.

Determinação da Capacidade de Hospedagem de Geração Distribuída Renovável em Sistemas de Distribuição de Energia Elétrica

Cristian A. Alvez — 2022-11-30

This paper presents a methodology to determine the maximum amount of renewable distributed generation that can be integrated into an electricity distribution system, without exceeding the voltage limits on buses and charging on lines and transformers. The methodology takes into account the random behavior of renewable generation and demand, as well as the three-phase model of the electricity network. To illustrate an application of the methodology, the hosting capacity of distribution systems with different lengths of lines and load levels was analyzed. The results show that in the system with long lines and lightly loaded the hosting capacity is limited by overvoltage problems, while in the system with short lines and highly loaded the hosting capacity is limited by the excessive load of the lines. Finally, it is noteworthy that the methodology presented can provide support to operators of distribution systems in the planning and operation.

Metodologia para reconfiguração de conjuntos de consumidores de acordo com a contiguidade de áreas

Wanderson L. Pereira — 2022-11-30

This article proposes a methodology for reconfiguration of sets of consumer units considering the contiguity of areas. The first part of the methodology consists of collecting historical data on occurrences that caused the interruption of electricity for groups of consumers, identifying the average interruption times and the frequency with which they occurred throughout the analyzed period. The objective of the present study is to identify possible adjustments in the configuration of the sets of consumers in order to obtain as a result the reduction of the values of the collective indicators of Equivalent Interruption Duration per Consumer (EID) and Equivalent Interruption Frequency per Consumer (EIF), which impacts the amounts of compensation (penalties) paid by the concessionaire for not meeting the limits stipulated for the collective performance indicators of the sets. To validate the proposed methodology, data from an electricity distributor located in Rio Grande do Sul were used, the results show that a reduction in the values of the collective indicators (EID and EIF) was achieved through the union of two substations distributing the total of consumer units of the new set the values of their respective individual indicators.

Parametrização para o Fluxo de Potência Continuado: Diferentes Métodos de Previsão e Correção via Injeção de Corrente

C. C. de Oliveira — 2022-11-30

The continuation power flow (CPF) is the most used static voltage stability analysis method, and consists of four steps: prediction, step size control, parameterization and correction, among which parameterization is a key factor to ensure the success of calculating the continuation power flow. In this work, CPF via current injection expressed in polar coordinates and other different configurations are presented for the complete tracing of the P-V curve without problems relating to the singularity of the Jacobian matrix. From the results, all methods are compared with each other and also with the power injection method commonly used for tracing the P-V curve, showing their efficiency.

Análise da Localização de Defeitos em Sistemas de Distribuição com Baixo Nível de Monitoramento

Rodrigo de A. Coelho — 2022-11-30

Voltage, current and frequency are quantities that characterize the behavior of the electrical power system. In a fault condition, the signals have specific aspects that help in the detection and location of faults. However, in large systems, the monitoring of signals does not always occur extensively. This fact is evident in the electrical distribution system (EDS), which presents a greater heterogeneity than the transmission systems. Within this context, one of the alternatives for fault location is the use of metaheuristics based on the states of protective devices. This work presents a study on the use of fault location techniques based on metaheuristics for EDS applications. For this purpose, a 33-bus test system was used to simulate faults and evaluate the status of circuit breakers and relays. Furthermore, in order to identify the level of importance of each device in the diagnosis, the impact of the weights assigned to relays and circuit breakers on the objective function was analyzed. The results were promising and indicated the feasibility of diagnosis of faults using metaheuristics, despite the low level of EDS monitoring.

Modelos de Séries Temporais em Cascata para Previsão da Velocidade do Vento

Wallace P. P. Porto — 2022-11-30

This paper proposes developing cascate time series models for forecasting of wind speed. It was developed the Seasonal Autoregressive Integrated Moving Average (SARIMA), Prophet, Cascaded Autoregressive Integrated Moving Average (ARIMAc) and Cascaded Prophet . The called cascaded times series models are an approach in which, unlike the others, the forecast was made using data from each time to distinct time series. From predicted data by time series, its was reassembled in the original order. The analysis and comparison of the performances of each model was carried out based on different evaluation criteria to determine the most accurated forecasting. Finally, the Bergmann-Hommel post-hoc test was applied to assess the level of difference between developed times series models.

Construção da tipologia de curvas de cargas harmônicas residenciais

Vanildo R. Neves Jr — 2022-11-30

This paper presents the results of applying a clustering methodology to obtain the harmonic typology of residential loads, considering both amplitude and phase angle for different orders of harmonic currents. For this purpose, the k-means clustering methodology was used, as well as the results of a measurement campaign carried out in the concession area of a large electric utility. The results obtained allowed the temporal characterization of the harmonic flow direction in the connection branches of residential low voltage consumers, duly stratified into different consumption classes.

Amortecimento ativo híbrido utilizando corrente do capacitor e tensão do ponto de conexão para inversor com filtro LCL

A. Braga Jr. — 2022-11-30

This work deals with a hybrid active damping of LCL grid-tied inverters. This hybrid method uses the point of common coupling voltage and the capacitor current as feedforward in the control action. Mathematical modelling of the system is carried out. The analysis of the impact of the choice of the gains in the frequency response and in the closed-loop poles positions is presented. Moreover, the impact of modelling or neglecting the implementation delay is evaliated and it is shown that the system becomes unstable quicker for an equal gain. A methodology for choosing the gains was developed verifying the damping of the pole closest to the unit circle. At last, it is shown the impact of changing the gains and the grid inductance in the control actions and the converter and grid currents.

Análise da propagação de harmônicas de alta frequência em uma rede de distribuição de baixa tensão

Kelly N. C. Silva — 2022-11-30

The development of solar photovoltaic generation systems into the grid, electric vehicles and electronic mass-market equipment is characterized by the growth of high frequency emissions in the range of 2–150 kHz. These high-frequency emissions, known as supraharmonics, negatively affect the power quality of electrical distribution systems. It is important to investigate and analyze the propagation of these high frequency currents on the grid for diagnosis and mitigation of any disturbances caused by them. This paper aims to study the propagation of supraharmonic emissions in the real power grid as presented in measurements in a connected photovoltaic inverter and simulations of a typical low voltage distibution grid. The simulations was made by using MATLAB Simulink® software to model a distribution grid including supraharmonic current sources allocated in different buses of the system. The results show that the voltage harmonic distortion levels depend on the frequency and impedance along the grid. Further, the results also explore the possibilities of this type of system, showing the consideration of a bank of capacitors (or the intrinsic capacitances of the system) leads almost the total attenuation of supra-harmonic voltages levels.

Análise Estatística para Seleção dos Atributos que Caracterizam os Indicadores de Continuidade do Fornecimento de Energia Elétrica

Jaderson Rosa dos Santos — 2022-11-30

To assess the quality of service provided by distributors, the National Electric Energy Agency (ANEEL) establishes service continuity indicators and limits for these indicators. The methodology for defining the limits is constantly updated, aiming to make it consistent with the characteristics of the distributors. In this context, the present work aims to analyze the change in the criteria of the statistical analysis for the selection of the attributes that characterize the continuity indicators. The proposed analysis is based on the same procedures used by ANEEL to define the current model for the characterization of continuity indicators, however, different statistical techniques from those employed by ANEEL are used. To validate the proposed methodology, eight case studies were developed using the software SAS University Edition. It was found that, using Stepwise regression, the increase in the correlation limit tends to decrease the explanatory power and the number of variables in the models, however, it increases the partial explanatory power of each variable present in the models.

Detecção de Ilhamento em Geração Distribuída Fotovoltaica em Tempo Real

Gabriela C. Zorzela — 2022-11-30

Real-time simulations have proven to be an important tool for system analysis because they present robust results that are more similar to the dynamics behavior of a real system. The objective of this paper is to evaluate passive islanding detection methods applied to a system with photovoltaic generation in the real-time simulator OPAL-RT©. The methods analyzed in this paper are Under/Over frequency, Under/Over voltage, the Rate of Change of Frequency (ROCOF) and the Rate of Change of Voltage (ROCOV). The parameters for performance evaluation of the methods were the detection time, the non-detection zone, and the occurrence of unintentional detections. The simulations were performed on a diagram built in HYPERSIM software, which allows the interface with the simulator in real time.

Determination of Critical Cavity Size on Stator Bar Insulation System Using a Finite Element Method Model

Alander R. Ribeiro — 2022-11-30

Partial discharge (PD) inside cavities causes aging of a stator bar groundwall insulation system that can generates a breakdown leading to equipment failures. One of the conditions to a PD occurrence is that the electric field (EF) within the cavity must exceed an inception field that mainly depends on the cavity size and pressure. A stator bar model has been simulated using Finite Element Method (FEM) in order to study the presence of a spherical cavity within the insulation. Simulation results and inception field calculation were used to determinate critical cavity size.

Efeitos da posição e nível de sombreamento na potência de saída da matriz fotovoltaica

Cláudio A.C. Cambambi — 2022-11-30

The power loss in a photovoltaic array under identical partial shading pattern is proportional to the percentage of shading. This makes sense, as the photovoltaic array depends on solar irradiance to generate electrical energy. However, it is tacitly assumed that the maximum power of a partially shaded PV array always decreases as the shading intensity increases. However, although poorly documented, it appears in the literature that this may not be the case. The investigation of the PV characteristic curve under different numbers of shaded modules and percentage of shading suggests that the photovoltaic array becomes insensitive to the percentage of shading when the irradiance of the shaded modules reaches a certain critical point. A series- connected and series-parallel photovoltaic array is used in this article. The critical point can vary based on the number of shaded modules, size and configuration of the PV array.

Aplicação do Método de Programação Dinâmica através do software OTIMIZA para o Despacho de Geração Distribuída em Microrrede da UFSM

Tiago Francisco Hinterholz — 2022-11-30

In carrying out the planning of the energy operation of an electrical system, it is sought to establish the participation of each generating unit in the electrical system, in order to ensure the supply of demand at the lowest possible operating cost, respecting technical restrictions. In this sense, the Dynamic Programming (DP) method, widely used in the electricity sector, is presented to determine the optimal dispatch of generating units, observing factors such as operating cost and maximum permissible power of each unit. And a case study is presented, which seeks to prioritize the application process for the dispatch of distributed generation (DG) of electric energy, from diesel generators, in a microgrid at the Federal University of Santa Maria (UFSM). For that, the results obtained in the simulations with the computer program OTIMIZA were analyzed, in order to obtain the optimized dispatch of the DG for the UFSM microgrid. With this, it is expected to meet the specified demand within normal operating conditions and with the lowest possible operating cost, avoiding demand overruns.

Aplicação do Método Particle Swarm Optimization na Obtenção de Nomogramas para a Avaliação da Segurança Dinâmica

Victor F. Carvalho — 2022-11-30

Dynamic Security Regions (DSR) are tridimensional graphics that evaluate the power system security when the system is divided into three generation groups, and the generated power is transferred among them. They allow the evaluation of different generation scenarios considering the security limits for the damping ratios associated with electromechanical oscillation modes. The main problem in obtaining the DSR is the high computational effort required due to the several power flows and modal analyses. This paper presents an efficient methodology based on the Particle Swarm Optimization method to obtain DSR. The results obtained for the New England test system are promising in the face of accuracy and the reduced computational burden.

Depreciação dos Transformadores em Função do Envelhecimento Causado pelas Distorções Harmônicas de Corrente

Fábio de Oliveira Carvalho — 2022-11-30

This paper presents a case that consists of an A4 (13,8 kV) consumer category, which uses a distribution transformer to connect their installations to the distribution power system. Some measurements were done, and a nonsinuidal load currents is verified. An analysis was carried out based on the concepts in the IEEE std 57.110/2018 and IEEE std 57.91/2011 standards, with the objective of quantifying the harmful phenomena that occurs in the distribution transformer, and the depreciation provided in this property in function of harmonic currents. The results obtained demonstrate that there may be a loss in the life expectancy of the transformer, accelerating the depreciation of the assets, negatively interfering in the costs of that company.

Uso de controle volt-var e volt-watt em uma rede de distribuição de baixa tensão com alta penetração fotovoltaica

Nyegirton Barreiros dos Santos Costa — 2022-11-30

Insertion of distributed micro and mini-generation systems in the Electrical Power System has shown high growth in recent years, with emphasis on photovoltaic generation. However, it is necessary to ensure that the efficiency and electrical power quality indices are within acceptable limits, in view of high penetration of distributed generation can cause a lot of problems in the network, mainly voltage deviation. Therefore, several studies seek to understand the impacts caused and possible solutions to minimize them. Thus, this work aims to evaluate the performance of controls available in intelligent inverters: volt-var and volt-watt, to mitigate voltage deviations caused by the massive insertion of photovoltaic systems in the grid. The study used a real low voltage distribution network located in the northeast region of Brazil through simulations in the software OpenDSS. The results show that although the controls are able to correct most cases of voltage deviation, the isolated actuation may not be enough. An analysis of technical losses was also performed.

Otimização de TSF analíticas para SRMs via Algoritmo Enxame de Partículas e Plataforma HIL

Gustavo X. Prestes — 2022-11-30

This paper features a performance comparative study between analytical torque- sharing functions. The optimal conditions of Oon and Oov were obtained by particle swarm algorithm as method to drive optimization of three-phase switching reluctance motor. The aim is to assess the level of core losses and torque ripple in each TSF, as well as current controller performance in different speed conditions. In order to work out simulation process in less time, the non-linear model developed in Typhoon/Python environment was used to have real-time results.

Influência da inserção do dispositivo STATCOM na proteção contra perda de excitação de geradores: Uma contribuição utilizando a lógica fuzzy

Victor M. P. Dutra — 2022-11-30

Brazil is a country with continental dimensions and has a power generation system interconnected with all regions, through transmission lines (TLs), allowing supply for its all-consumption centers. However, building new TLs may be unfeasible in an environmental and financial sense. With the advancement of power electronics, FACTS (Flexible Alternating Current Transmission Systems) devices were created, which are based on series or parallel reactive compensation in the network, allowing flexibility in system operation, with lower transmission losses and better stability. However, the insertion of such devices may cause the maloperation of synchronous generators protection. In this sense, this work presents the effects of inserting one FACTS model (STATCOM - Static Synchronous Compensator), in relation to the protection system against the loss of excitation of synchronous generators. To identify and improve the protection response against loss of excitation, it is proposed to use a fuzzy classifier, which has its effectiveness compared to the traditional scheme that uses the impedance characteristic.

MÉTODO DA SOMA DE POTÊNCIAS PARA SOLUÇÃO DO FLUXO DE POTÊNCIA EM REDES DE DISTRIBUIÇÃO TRIFÁSICAS E DESBALANCEADAS

Edivan Q. P. Regis — 2022-11-30

the power sum method (PSM) is very accurate for solving the power flow and has a fast convergence in radial networks. Its formulation represents the power balance in terms of the power flows in the lines. This facilitates its application in the optimal power flow model by composing part of the set of equality constraints. As the conventional PSM uses a positive sequence representation and the distribution networks are three-phase and unbalanced, then, in this work, an expansion of its fundamental equation of the PSM is proposed to calculate the three-phase nodal voltages. The process of evaluating the accuracy of the proposed formulation is comparatively carried out through the solution of the power flow under an unbalanced three-phase distribution network of 135 buses.

Impacto nas compensações financeiras considerando nova configuração de conjuntos de unidades consumidoras de uma distribuidora de energia elétrica

André R. Borniatti — 2022-11-30

The regulation in the public electric energy distribution service considers quality and continuity indicators, presented in Module 8 of the Electric Energy Distribution Procedures in the National Electric System (PRODIST), established by the National Electric Energy Agency (ANEEL). Collective continuity indicators are defined for measuring the distribution quality services, such as: Equivalent Interruption Duration per Consumer Unit (DEC) and Equivalent Interruption Frequency per Consumer Unit (FEC). Also, there are several individual indicators of continuity that deal with the single consumer unit interruption, such as: duration (DIC), frequency (FIC), maximum duration (DMIC) and on a critical day (DICRI).Each of these individual indicators has a stablished limit value, which, if exceeded, results in financial compensation by the distributor (utility) directly to the consumer units. In this way, this paper presents a methodology applied in an algorithm developed using the Matlab software with the purpose of analyzing these indicators impacts along with their financial compensation for modified configuration of the current sets of consumer units of an energy utility. This configuration change is based on the contiguity criteria, which appear in Module 8 of PRODIST. For the development and application of the methodology, initially each substation is considered as a unit of consumers combined. The new proposed configuration achieved a reduction of around 1% in the total amount of financial compensation paid by the utility between the years of 2017 to 2020. This compensation refers to the monthly period, for the DIC, FIC and DMIC indicators. Meaning there is a possibility of future gains by carrying out a reconfiguration of sets without the requiring investment in the grid system.

Previsão da Irradiação Solar Fotovoltaica baseada em Deep Learning

Felipe de Sena Rodrigues — 2022-11-30

The Northeast area has shown great potential for generating of solar energy in Brazil, for this reason several energy companies have evaluated the economics feasibility this kind of renewable energy. Thus, as it increases the portion of renewables sources in supply of energy is important to estimate your potential with an acceptable accuracy in distincts horizons, like hours, days, weeks, and months. This paper proposed to develop distinct deep learning models for forecasting the global solar irradiation. The measures were collected from a solarimetric station located in the State of Bahia. The models are evaluated through five performance metrics, and the best results were selected for the final models. Finally, Friedman statistical test and Bergmann-Hommel’s post hoc test were applied to evaluate the hypothesis for significance difference between the developed models.

Controle de um Retificador Buck-boost de Elevado Fator de Potëncia para Acionamentos de LED’s

Pedro Henrique C. Lopes — 2022-11-30

In Brazil, public lighting consumes about 97 billion kWh per year, featuring lamps with low luminous efficiency. To reduce consumption, one solution is to increase the use of lamps with greater luminous efficacy, such as LED (Light Emitting Diode) lamps. For its activation, an AC-DC conversion process for rectification of the network voltage is necessary, which causes some power quality problems, such as a distortion of the network current and a low power factor. To solve these effects, this work uses active power factor correction methods, through a buck-boost converter such as PFC (Power Factor Correction) to emulate a purely resistive load, knowing that its operation in mode discontinuous has an intrinsic function of PFC. An exhaustive study was developed in order to design the control in the converter to protect against possible disturbances and to comply with the IEC 61000-3-2 standard. These measurements ensured system operation with power factor above 0,98 and total harmonic distortion close to zero.

Análise Comparativa entre Fontes Despacháveis para Microrredes

Diogo N. Abreu — 2022-11-30

This paper analyzes two alternatives of dispatchable generation sources applied to the context of microgrids, considering that the presence of renewable sources entails in an imbalance between electric energy generation and demand towards such electric system. However, if the microgrid is connected to the main grid, the surplus and/or deficit of energy is assumed by the main system. Although, if the situation becomes critical if the sum between load and generation is different than zero and the microgrid is isolated. Therefore, two microgrids scenarios were analyzed considering the possible applications of two dispatchable generation sources: diesel generators and gas generators. In the first case, the inexistence of gas pipelines made the application of the gas generator unfeasible and in the second case, with the help of HOMER software, an advantage of diesel generator in terms of fuel costs was perceived, but with the gas generator being advisable for cogeneration applications.

Estudo comparativo dos efeitos das compensações série e paralelo na proteção de Linhas de Transmissão

Raphael F. Oliveira — 2022-11-30

The FACTS (Flexible AC Transmission Systems) devices have great use in the Electric Power System (EPS) for the dynamic control of the active and reactive powers of the system. This work deals with a comparative analysis between the effects caused in the distance protection of transmission lines (TLs) by two of these devices: the STATCOM (Static Synchronous Compensator) and the SSSC (Static Synchronous Series Compensator). The objective is to verify how the connections of these two converters, connected in series in the case of SSSC and in parallel for STATCOM, influence the characteristics of the distance protection in relation to the range of the distance relay. Computational simulations were made using the PSCAD/EMTDC software where both the electrical system under analysis and FACTS were modeled and the protection zones for one of these lines were defined. After the section was protected, the FACTS were inserted and short circuits between phases and between phase and ground were applied, both in the presence and in the absence of the FACTS for comparative analysis. Once the effects of FACTS devices on distance protection in a simulation environment were verified, laboratory tests were carried out to ensure compliance among the results.

Análise dos Impactos Provenientes da Instalação de Bancos de Capacitores na Fronteira com a Rede Básica

Camilla P. Nakanami — 2022-11-30

The continuous verification of performance indicators and the minimum technical requirements required by the regulation of the electricity sector aim to list conditions that may affect the operation of the electric power system and the performance of its equipment. The power factor, although monitored in steady state, provides an increase in electromagnetic transients in that system due to the switching of capacitor banks with the objective of providing adequacy of its value range. In this way, it is proposed to determine a range of capacitive reactive power values that allow not exceeding the reference values assigned to the steady state voltage of the power system, to the energizing transients of the shunt capacitor banks and the transient recovery voltage in the circuit breakers adjacent to the busbar at 138 kV from the secondary of 2 basic network transformers at voltages of 440kV and 500 kV. The analyzes involved 2 load level scenarios. In view of the model used and the conditions simulated in ATPdraw computer program, the capacitor banks of 20 MVAr, 40 MVAr and 60 MVAr allowed to achieve the proposed objectives.

Modelos de Negócios e Aspectos Regulatórios para Inserção de Sistemas de Armazenamento de Energia por Baterias no Setor Elétrico Brasileiro

Júlio César Cândido Vieira — 2022-11-30

Battery energy storage systems (BESS) represent a promising technology to support the energy transition in the electricity grid. BESS can offer different types of services to the electricity grid among which the following stand out: power smoothing of renewable sources generation, energy arbitrage and provisions of ancillary services, such as voltage and frequency regulation. In this context, many countries, such as the United States, have already defined regulatory frameworks to ensure the BESS dissemination in the electricity grid. However, the Brazilian normative regulation regarding the BESS installation and operation is still in an initial state, which does not guarantee legal assurance for investments in the sector. This paper presents the business models and the regulatory and tax challenges that must be overcome to incentive the use of BESS in Brazil.

Árvores de decisão aplicadas à redução de múltipla estimação de faltas em sistemas de distribuição de média tensão

A. L. Moraes — 2022-11-30

Fault location is not a trivial task in distribution systems, since the radial characteristic of the feeders makes fault locators present multiple estimations (especially those based on impedance). In this sense, there is difficult to accurately locate the fault. Therefore, this work presents a decision tree-based approach to reduce the multiple fault estimation issue. For this purpose, the feeder was divided into sectors, which do not overlap. Next, five types of faults were considered in the simulations, which were performed by using the PSCAD™/EMTDC™software. It is worth mentioning that only one meter was used, allocated in the substation. Thus, the voltage and current signals from this meter were subjected to a feature extraction process that, in turn, were used as inputs to decision trees that could be trained and validated to locate the faulted sector. Based on the results, the proposed approach was able to identify above 96.3% for sectors under single-phase faults, 84.3% for two-phase faults and 73.0% for three-phase faults.

Gerenciamento Inteligente de Energia entre Baterias e Ultracapacitores em Veículos Elétricos Leves com Otimização por Enxame de Partículas

Márcio V. R. Campos — 2022-11-30

This article presents the modeling of a DC microgrid formed by the integration of lithium batteries and a bank of ultracapacitors (UCs), applied in electric vehicles of the Formula SAE competition. A control strategy is applied for the proper management between the energy sources, in order to increase the cycling of the batteries and to explore the characteristics of the UCs, which have a high energy gradient to assist in the peaks of power events in the generation and braking regenerative energy while driving the vehicle. Computational tools were used to model the systems, collect electrical data and apply particle swarm optimization (PSO). The system simulated an improvement in battery energy consumption of more than 10% with less stress from electrical current peaks on the Piracicaba-SP track, where the SAE competitions take place.

Minimizando o custo global de Infraestrutura de Comunicação e alocação de PMUs em WAMS: uma abordagem via grafos

Vanessa B. Boone — 2022-11-30

In this paper, we present a new method for the design of WAMS (Wide Area Measurement Systems). State estimation is responsible for processing measurements in real time and providing a complete and secure database for Wide Area Measurement Systems, therefore the power system is increasingly dependent on PMU measurements. The high cost of the communication infrastructure together with the cost of the PMU encouraged the development of new PMU placement solutions in order to ensure the observability of the system. The new methodology has an emphasis on optimizing the cost of the communication infrastructure, so that the smallest number of PMUs satisfies the condition of a lower total cost. Our results show the effectiveness of the proposed methodology when compared to research in recent previous works. The simulations were performed using IEEE-14, IEEE-30, IEEE-118 and IEEE-300 standards.

EFEITOS DA INSERÇÃO DE SVC E TCSC NA ESTABILIDADE ANGULAR TRANSITÓRIA E NA PROTEÇÃO CONTRA PERDA DE EXCITAÇÃO DE MÁQUINAS SÍNCRONAS

J. P. G. S. Filho — 2022-11-30

This work presents a methodology, based on the modeling of an electrical power system test created in the PSCAD/EMTDC simulation environment. The purpose is to evaluate, at first, the impacts that Thyristor Controlled Series Compensator (TCSC) and Static Var Compensator (SVC) cause in the transient angular stability of the system generators against disturbances, evaluating the rotor displacement of the synchronous generators under analysis. In a second moment, the behavior of the ANSI 40 protection function is evaluated for conditions of total and partial loss of excitation since this protection function uses the impedance information for its operation. The results indicate that the compensators can improve the transient angular stability of generators against disturbances. And about the behavior of the ANSI 40 func- tion, a change in the time that the impedance trajectory reaches the protection zones was identified

Simulação de Transitórios Eletromecânicos e Análise da Estabilidade a Pequenas Perturbações através de ferramentas desenvolvidas em Python

Jonathan V. França — 2022-11-30

Computer simulations are an important tool for the expansion and operation of electrical systems. Within the simulations carried out for the study of electrical systems, there is the simulation of electromechanical transients, and this type of simulation is extremely important for the study of stability in electrical systems. This work aims to show the development of two electrical systems simulation codes written in Python language, one dedicated to time simulation of electromechanical transi1ents and the other to the analysis of angular stability at small disturbances. These codes were applied in the simulation of a 14-bus system, presenting results that converge with traditional software.

Modelagem e análise da proteção anti-ilhamento de geradores distribuídos térmicos e fotovoltaicos

Rodrigo T. Toledo — 2022-11-30

This paper presents an analysis of the anti-islanding protection (AIP) functions behavior during the islanded operation of a distribution network section that contains simul- taneously distributed generators interfaced by inverters and directly connected to the grid via synchronous generator. Through the simulations carried out, it was verified that the tripping time of traditional passive islanding detection functions is significantly affected when there are synchronous generators connected to the island. This is due to the existence of a synchronous, although weak, reference for the photovoltaic generator, extending its islanded operation. It was also verified the need for greater care in the parameterization of AIP functions as well as the complementation of more robust and sensitive detection functions in order to ensure greater network reliability and security.

Impactos da Inserção de Grandes Parques Eólicos na Estabilidade Angular Transitória do Sistema

Davi M. Silva — 2022-11-30

With the increasing number of wind farms in the interconnected electrical system, the impact of the penetration of this type of renewable generation has become a very important issue, especially when it comes to maintaining the stability of the system. From this scenario, this work investigates the influence on the transient angular stability due to the entry of large wind farms that use the technology of double fed induction generator. Seeking to increase the contribution of wind turbines in damping oscillations, this work proposes the installation of an additional stabilizing signal in the voltage control loop associated with wind turbine rotor converters. The proposed methodology is then validated in an equivalent Brazilian system in the presence of large perturbations. The results obtained show that the procedure performed contributes to the reduction of oscillations and increase of the damping of impacts, mainly considering faults in the vicinity of the coupling point of the wind farms to the interconnected system.

SISTEMA DE DISTRIBUIÇÃO T2F: VERIFICAÇÃO DA EFETIVIDADE DAS METODOLOGIAS DE COMPENSAÇÃO DE DESEQUILÍBRIOS DE TENSÃO

Leonardo de Freitas Silveira — 2022-11-30

This work presents a study of the effectiveness of the compensation impedance calculation methodology for the intrinsically unbalanced three-phase power distribution system (T2F). The calculation methodology in question is based on the Carson’s image method to obtain impedance values that, when arranged longitudinally and transversally to the system, equalize it in order to reduce voltage unbalance levels (%DT). The comparison of the effectiveness of the calculated compensation is performed through the proposal of a computational method to obtain the impedance values that equalize the system in order to completely eliminate the unbalance between the phases. This study shows that factors such as the value of impedances implemented and their arrangement in the system directly imply the results of %DT measured in the load coupled to the circuit.

Diretrizes de Projeto para Digitalização de uma Subestação de Energia Elétrica

Flávio Garlet Reck — 2022-11-30

The standard IEC 61850 has been used in Brazil since 2008 to systematize the parameters of data communication regarding substation automation in an open, interoperable framework. Most electrical projects, which apply the standard IEC 61850, take only GOOSE message and MMS through the station bus. However, the standard recommends a second bus, named process bus. In 2022 the application of process bus is limited to pilot-project on electrical utility only to learn about its use and impact on substation operation. The analysis of technical reports concluded that there is no engineering approach to design a substation automation project within the station and process bus. Therefore, this paper aims to introduce a procedure to design a fully digital substation according to standard IEC 61850. The approach presented has been applied in a 15 kV substation.

Análise do Risco de Falha Associado a Métodos de Controle de Sobretensões de Energização em Linhas de Transmissão Compactas

Renato V. Oliveira — 2022-11-30

This paper analyses the risk of failure associated with control methods for overvoltages due to compact transmission-line (CTL) energization. The Approximate Statistical Insulation Coordination Method is applied different control methods to verify which will be very suitable for long CTL. The results are analyzed according to different devices and configurations using pre-insertion resistor, controlled switching and, transmission-line surge arrester. The software ATPDraw was used to obtain the results, where the High-Voltage (HV) systems in 500 kV with statistical switching were modeled. The results show that the smaller risks of failure are obtained with pre-insertion resistor associated with controlled switching, significantly decreasing the line- to-ground overvoltages of the CTL. Furthermore, this paper shows a study about increasing of the risk of failure associated to reduction of the insulation spacing in CTL.

Uso do Campo Elétrico na Geração de Alarmes para Risco de Descargas Atmosféricas

Bruno A. S. Oliveira — 2022-11-30

Statistics show that Brazil is the country with the highest incidence of atmospheric discharges in the world. Only in 2020 and 2021, there were 280 million lightning strikes in the country. On average, there are 110 deaths and 300 injuries per year, according to INPE, based on the period between 2000 and 2019, when there were 2,194 deaths due to the occurrence of atmospheric discharges. Private sector investments have been made in an attempt to predict this phenomenon to minimize the impacts caused. One of the ways to monitor lightning is through electric field sensors. In this way, the objective of this work was to carry out a qualitative and quantitative analysis of the relationship between electric field data and atmospheric discharges for an area in the central region of the state of Minas Gerais. As a result, it was found that a system for generating alarms using only the electric field sensor should be used with caution since numerous cases of discharges were seen in which there was no variation in the electric field at the same time. On the other hand, the electric field can help in the decision-making of the system, if used in conjunction with lightning data.

Proposta de Execução de um Método de Gerenciamento de Demanda através de Controle Externo de Inversor Fotovoltaico com Bateria

João Felipe A. Santiago — 2022-11-30

The energy management method called Peak Shaving is a valuable approach, which increases the efficiency of the electricity grid and reduces costs for consumer agents, especially in contexts of high demand. Furthermore, this technique proves to be interesting for the new Brazilian energy challenges. This work proposes to build a computational infrastructure in order to enable the execution of this energy management method through a photovoltaic generation unit. In this sense, the construction of a supervisory will be presented, which will provide a view of the behaviour of the multiple electrical variables, which involve the generation unit, enabling the realisation of the energy optimization technique. This system consisted of a Modbus serial communication, MQTT message protocol, Python programming language, InfluxDB database and the Grafana interactive viewer. The infrastructure development was satisfactory with regard to data monitoring, but the control steps did not meet the design requirements.

Predição de descargas atmosféricas utilizando Machine Learning para prevenção de acidentes

Marcos A. Alves — 2022-11-30

The occurrence of atmospheric discharges poses risks to the the company operations and workers in open-air activities. Due to this, this paper aimed to cluster lightning data, simulating real- time monitoring of storms for three different target regions. In addition, storms information were used to predict, 15-minutes earlier, the probability of a lightning strikes these areas. Using a multi-source database from ELAT/INPE, different clusterization methods were evaluated in terms of the Calinski Harabasz, Davies Bouldin and Silhouette metrics. Overall, the best one was the MeanShift which cluster the data in 3-5 storms. Number of storms, density and distance were used into a classification machine learning model to generate warning alerts. The Extreme Gradient Boosting and Support Vector Machines achieved the best results in terms of precision and recall, important metrics to evaluate true and false alerts in this context. Both the false alerts, which implies in inactivity of operations and failure rate were equal to or lower than 40%.

Análise da viabilidade de migração para o ambiente de contratação livre e o impacto econômico com as recargas de uma frota de veículos elétricos

Cíntia H. Flesch — 2022-11-30

The electricity market has two contracting environments: the regulated contracting environment (ACR) and the free contracting environment (ACL). In the ACR the price of energy is established in auctions for the distributors and in the ACL the prices are freely negotiated between consumer and generator. One of the alternatives for reducing costs in a sustainable way is to migrate to the ACL, because the company can choose which source it wants to buy energy from. In addition, the electrification of the vehicle fleet is one of the realities that comes to contribute to cost reduction during operation and is seen as an alternative to impact the reduction of pollutant emissions in order to build a more sustainable environment. Thus, the objective of the study is to conduct an analysis of the feasibility of migration to the free contracting environment and the impact that this migration would cause economically on the supply of the vehicle fleet. The study showed that the migration from ACR to ACL presents significant savings for the consumer, since he/she has a fixed value of the energy tariff and does not perceive the impacts related to the tariff flags. Finally, the insertion of the electric vehicle fleet presented favorable results for the consumer and for the environment by contributing to the reduction of environmental impacts.

Avalição de Segurança de Pessoas em Redes Rurais que Utilizam o Solo como Meio Condutor

G. Cardoso, Jr. — 2022-11-30

Electrical grounding is essential for an electric power distribution system, even more so in networks with the ground return. Amid the expansion of rural power systems, the cost of a three-phase network can make the project impossible, restricting the consumer to a SWER system. Recent studies have proposed the construction of a three-phase network from a SWER system. In this case, the earth is used with a phase conductor. This would make the installation of three-phase networks in rural areas financially viable. However, security issues still need to be evaluated for this type of structure. This work aims to study the security characteristics to implement such a network. The equations and safety assessments were performed in a virtual environment, but the soil stratification was based on results measured in a test terrain that proved to be safe in its operation even with several rods.

Metodologia para Detecção de Possíveis Ocorrências de Perdas Não Técnicas em Consumidores Rurais Aplicando Métodos de Machine Learning

Natalia B. Sousa — 2022-11-30

The difficulty of detecting non-technical losses by electric energy concessionaires has been a great and constant challenge. Inspecting consumer units located in rural areas demands excessive time and expenses on the part of concessionaires, due to the distance from urban centers and the difficulty of access, without there being a previous technical indication of the occurrence of Non-Technical Losses. This work aims to present a methodology for estimating electricity consumption for rice crops that use flood irrigation, in the city of Uruguaiana, Rio Grande do Sul, implementing classification using artificial intelligence techniques (clustering, k- means and random forest), and with the help of indicators, report cases of possible non-technical losses.

Análise da Influência Regulatória no Contexto dos Sistemas de Armazenamento de Energia Elétrica na América do Sul

Renata R. Lautert — 2022-11-30

This paper presents the general aspects related to the regulation of electric energy storage, within the Brazilian and South America context. Furthermore, to delimit the range of contents associated with this theme, a contextualization on the subject will be described, along with an analysis focused on administrative issues and existing restrictions. In the search for the theoretical consolidation of the study and the regulatory influence in the context of energy storage, the aim is to illustrate certain works found in the literature, which are correlated with the research carried out in this article. The importance of dealing with the regulatory variable for energy storage is in the fact that future business models will be directly influenced by economic changes arising from it.

Modelagem Computacional do Sistema Elétrico de uma Plataforma de Petróleo

Felipe Thomazi Moreira — 2022-11-30

Oil and natural gas are very important energy sources on the planet, representing a very significant percentage in the energy matrix, not only in Brazil, but also worldwide. In this context has an extremely privileged geographic position, a fact that was reinforced when, in 2007, the discovery of pre-salt reserves was announced, where it is estimated the presence of up to 176 billion barrels of oil equivalent. For the exploration of this reservoir, the development of new offshore platforms is planned, mainly FPSOs - Floating Production Storage and Offloading, which rely on highly complex industrial systems, requiring systems of great power, with large machines and, consequently, high-capacity electrical generators. Thus, this work aims to model the isolated electrical system of an FPSO in order to be able to carry out power flow and short circuit studies quickly and effectively. The methodology consists of using real data from an oil platform, modeling the system using OpenDSS software and, when possible, comparing results obtained from other models or conventional values found in the literature.

Metodologia de projeto para um filtro LCL modificado com adição de um indutor de modo-comum para aplicações fotovoltaicas sem transformador conectadas à rede

Diego Chaves — 2022-11-30

Grid-connected transformerless photovoltaic (PV) systems have become very popu- lar, due to their smaller size/weight, greater efficiency and lower cost. However, the common- mode voltage (CM) generated in power inverters causes leakage current, which according to PV standards, must be limited. Among different methods to limit leakage current, the modified LCL (MLCL) filter with passive damping is an efficient and simple solution. However, it is necessary to oversize the components of the MLCL filter to keep the leakage current below 300 mA rms, established by PV standards, increasing the size of the differential inductors. On the other hand, a CM inductor can be added to limit the leakage current. These inductors process less energy, and therefore considerably reduce the total volume of magnetic devices in the power stage. This paper presents a methodology to size the elements of an MLCL filter with a CM inductor that complies with the PV standards, in a transformerless three-phase two-level grid-connected inverter. Simulation results are presented to confirm the theoretical analyses.

Avaliação de Sobretensões Resultantes de Faltas Monofásicas em Sistemas de Distribuição com Geração Distribuída

Álvaro Bampi — 2022-11-30

This paper evaluates different scenarios of single-phase faults in the medium voltage system operating in island and supplied by distributed generation (DG) with synchronous generator in steady state, observing the resulting overvoltages due to the delta connection in the primary of the coupling transformer. In this context, the present document proposes to contribute to the technical issues related to the connection of DG, presenting a series of simulations carried out in ATP Draw, considering installations framed in the simplified primary standard. It is not intended here to exhaust all possible technical possibilities but rather to assess how each of the main parameters influences the overvoltages resulting from single-phase faults and whether or not the neutral overvoltage protection function (ANSI 59N) is mandatory for these installations. The results indicate that significant overvoltages may occur in the system depending on load, generation, and fault impedance conditions.

Teoria da Potência Conservativa Aplicada ao Compartilhamento de Responsabilidades Devido às Distorções Harmônicas de Tensão: Considerações e Estudo de Casos

Luciano J. Menezes — 2022-11-30

The insertion of equipment with nonlinear characteristics in the electrical system has increased exponentially in the last decades. It is known that despite the benefits of such technological advances, there is the possibility of power quality degradation. In this context, when the limits of harmonic distortions are above the maximum allowed in the regulations, the concern of sharing responsibility among the agents involved in this deterioration of power quality arises, indicating, consequently, the financial division of possible mitigating actions. Therefore, this paper aims to compare the Conservative Power Theory (CPT), in the scenario of responsibility sharing due to voltage harmonic distortions, with the Superposition method. It is important to highlight that the Superposition of Voltages methodology, presents itself as a template for the study of other methods. To fulfill the proposed objective, the MATLAB/Simulink computational tool will be used. In the present work, four cases will be evaluated.

Análise de Fatores Socioeconômicos em Relação ao Crescimento da Geração Distribuída no Brasil

Guilherme Rezende Pereira Camargo — 2022-11-30

Over the past few years, the issue of using renewable sources to generate electricity has been highlighted, after all, conventional means degrade the environment, in addition to requiring a high generation cost. This perspective takes us to the photovoltaic scenario, with the first solar plant being installed in Brazil in 2011, from that onwards, a strong generation model is evidenced to address the issues of sustainable economic development. Currently, the energy generated through photovoltaic solar modules has grown exponentially and still has a great generation potential, after all has an excellent rate of solar irradiation, but when analyzing this potential, which has not yet been reached, questions are raised about variables that can leverage this growth or that are somehow correlated. Thus, the current work aims to raise studies on photovoltaic systems, the influence of socioeconomic factors in relation to the growth of photovoltaic generation, using statistical techniques to analyze the level of correlation between these variables. To carry out this analysis, it was necessary to obtain data from certain regions, such as the socioeconomic indices being taken from the website of the Brazilian Institute of Geography and Statistics and the installed power, obtained through the website of the National Agency of Electricity. Thus, it is possible to apply mathematical techniques and develop graphics through the Python programming language, finally generating results where it is possible to quantify the correlation and state that a certain socioeconomic factor is responsible for such a generation index in that particular analyzed location.

An Investigation of the Potentialities of the Electromagnetic Frequency Regulator

Ariel S.L. Patriota — 2022-11-30

This work analyzes the Electromagnetic Frequency Regulator (EFR) when used in a wind power system with hybridization of energy sources. The study was conducted through numerical simulation on Scilab platform. The conventional mechanical transmission (gearbox) was substituted by a hydrostatic system (pump and motor). Feedback linearization was used to control the motor’s displacement, and a prediction algorithm was developed to compute the reference steady-state angular speeds of the EFR’s armature and the rotating electromagnetic field. The results indicated that the EFR can effectively supply the generator load regardless of the wind speed. It was also shown that electrical energy can be accumulated in batteries during regimes of wind speeds higher than a reference set-point, to be used when the harnessed wind power is lower than the load. This shows that the EFR is a viable hybridization solution to wind energy systems, ensuring the highest levels of power quality.

Método para Avaliação do Impacto de Obras de Expansão na Confiabilidade de Redes de Distribuição

Gustavo L. Aschidamini — 2022-11-30

This work proposes a method to assess the impact on reliability coming from the expansion of primary distribution networks. The reliability is estimated analytically, while the failure rates of sectors are determined based on the failure history of the primary network and by the adjustment of the estimated reliability indices to historical average values. The method described here was applied to a real distribution feeder of an energy distribution company, allowing the determination of future reliability indices and energy not supplied assuming no expansion takes place and also considering expansion plans that include i) installation of normally-open switches with interconnection to adjacent feeders, ii) automation of switches, and iii) reconductoring of primary network sectors. The results demonstrated that the proposed method can support the decision-making process, thus leading to investments more attractive concerning the improvement of the reliability indices and reduction of the energy not supplied.

Valoração dos Impactos da Geração Distribuída no Equilíbrio Econômico-financeiro da Concessionária Considerando um Modelo de Negócios

Gustavo De Lazari — 2022-11-30

The growth of Distributed Generation (DG), especially the Photovoltaic Solar Energy (PV), for the residential and commercial low voltage (LV) consumers, instigates the discussion on the valuation of DG impacts on the economic-financial balance of utilities. In this way, this work proposes a methodology that projects the adoption of PV, simulates the technical impact on the electricity grid, and calculates the economic-financial impact on the utilities’ cash flow. This methodology is applied in scenarios that reproduce the current regulation and a business model with concentrated storage in medium voltage. Through the electro-energetic simulations, it is concluded that the adoption of PV by LV consumers reduces the energy demanded, which is directly reflected in loss of revenue energy for the utilities. Likewise, the growth of PV contributes to the decrease of Minimum Demand and Power Factor, and overvoltage issues. Regarding the economic-financial impact, it is concluded that pricing consumers for the use of the Distribution System is the most profitable way for the utilities to be reimbursed for the availability of the electrical network. In addition, the business model was able to decrease the Maximum Demand, performing a peak shaving on the feeder load curve.

Estudo da Máxima Capacidade de Acomodação de Geração Distribuída de uma Rede de Distribuição em um Campus Universitário

Ana C. B. Gontijo — 2022-11-30

The present work aims to estimate the hosting capacity for the generation when considering the voltage metrics of a university campus’ distribution system. The voltage thresholds are established by Prodist module 8. Computational tools were used to analyze and define the good possibilities to make the most efficient use of available energy potential.

DIFUSA˜O DE SISTEMAS DE MICROGERAÇÃO FOTOVOLTAICA EM ÁREAS RURAIS: ESTUDO DE CASO

Nilson B. Mazzurana — 2022-11-30

The expansion of distributed energy resources, in particular distributed micro and distributed minigeneration systems, are transforming the energy infrastructure of the electricity sector. In dealing with these changes, the models of predictive dissemination of technologies prove to be fundamental instruments support the decision-making process for improving the legal framework and public policies. In this sense, this article is addressed to the study of the diffusion of photovoltaic microgeneration systems in rural areas. The influences introduced by the new credit compensation system of Law No. 14,300 of january 2022 are evaluated, as well as tax incentives in the electricity tariff to the rural agricultural underclass. The study is based on data from a rural electrification cooperative in the state of Rio Grande do Sul. As a highlight point, the results obtained indicate that changes in credit clearing rules have importante impacts, especially in the rural farming underclass of the cooperative under study, with a 28.16 % reduction in the prospected adoption rate of photovoltaic microgeneration systems.

Dimensionamento de Conversor Buck Entrelaçado de N Ramos Para Utilização em Carregadores Rápidos de Veículos Elétricos

Victor C. de Arruda — 2022-11-30

This work presents a methodology to select the inductors and the output capacitor for a N-branch interleaved buck converter for electric vehicle charging applications. Using this analysis, its possible to specify the passive components so that the output ripple of the current is below a certain limit, as defined in the IEC 61851-23:2014 standard for electrical vehicles charging. Additionally, it is presented a methodology to define the critical current in each inductor for operation in continuous current mode. Simulations results are shown to validate the proposed design technique and control algorithm.

Desafios e Perspectivas para o Setor Elétrico Brasileiro junto aos Leilões de Geração no Ambiente de Contratação Regulada

Luan Ribeiro Braga — 2022-11-30

The Brazilian Electricity Sector currently has about 175 GW of installed power for energy generation allocated within the extensive territorial dimension and its diverse electrical matrix. Several regulatory and governmental bodies study and implement actions to guarantee the energy supply. Electric energy auctions take place every year to contract new concessions for the provision of public energy distribution services. In this work, based on real data collected from the Energy Research Company and the National Electric Energy Agency, mainly, the current consolidated numbers on generation auctions in the Regulated Contracting Environment are addressed, presenting the amount of power to be installed, type of source/power plant, average price, energy sold and financial investments in the captive market. The status of generation projects that have already participated in these auctions and the issue of delays in the start of commercial electric energy operations were also addressed.

Construção de modelos de redes de distribuição a partir de sistemas de informação geográfica utilizando grafos

Marcelo Tenesaca-Caldas — 2022-11-30

The integration of renewable distributed generation and new technologies in modern power distribution networks brings changes in the operation and planning of these networks. The evaluation of these changes requires increasingly detailed computational models of the distribution network to be used by specialized analysis and simulation tools. In this work, an efficient methodology is presented that allows building network models for two electrical systems analysis software from the information available in a geographic information system, and using graph theory. The two types of network models built are used by the DIgSILENT PowerFactory and OpenDSS software, which allow carrying out studies and simulations to evaluate the new challenges in the operation and planning of the distribution system. The performance of the proposed methodology is evaluated in the construction of models of real distribution feeders of an Ecuadorian utility.

Métodos de Bloqueio por Oscilações de Potência: Uma Análise em Linhas de Transmissão de Três Terminais

M. Veiga — 2022-11-30

The disturbances resulting from Power Swing (PS) cause, in a harmful way to the electrical power system (SEP), acceleration or delay in the rotor angle between synchronous generators in relation to the synchronous frequency. In this way, in order to inhibit undue occurrences of the distance protection (ANSI 21 function), the detection of the PS phenomenon, as well as the action, is corroborated through the blocking (ANSI 68 function). Three-terminal transmission lines are a cost-saving option as there is a reduction in the cost of building the line. However, the complexity and challenge of line protection increases, especially with regard to the distance relay. Thus, this work aims to analyze the performance of three methods, established for two-terminal lines, when applied in a system with three-terminal lines. The algorithms Concentric Characteristics Method, Double Blinder Method and Electric Center Voltage Variation Method were implemented. The obtained results show that the MVTCE presents better performance among the evaluated methods.

Análise de Dados Aplicada às Chamadas de Emergência em um Sistema de Distribuição Real

Arthur H. M. de Oliveira — 2022-11-30

This work uses data analysis related to emergency calls from customers of a power distribution utility in Brazil, in order to investigate how temporal aspects and climatic characteristics influence the demands of the electricity grid and how these aspects are correlated with the number of calls received in a power distribution system over time. Therefore, a statistical analysis was performed based on the calculation of Pearson’s coefficient correlation for data with numerical characteristics and on the chi-square test that verifies the association of categorical characteristics with the number of calls. Numerical and day-of-the-week classifications of climatic data were proposed. As a result, it was found that the impact of these manipulations has a greater influence on the number of calls received by the concessionaire, allowing a better understanding of the most significant root causes for the increase in the number of calls in energy distribution systems in the country.

Estudo de Caso Associado com a Metodologia para Atribuição da Responsabilidade das VTCD's baseada no Fator de Desequilíbrio de Tensão

Ábner Cézar Peres Pacheco — 2022-11-30

A busca por procedimentos de campo destinados à identificação da origem das Variações de Tensão de Curta Duração – VTCDs, e outros fenômenos, se apresenta como desafios relevantes para a área da Qualidade da Energia. Focando pontualmente a questão dos distúrbios ora mencionados, estudos anteriores evidenciaram perspectivas promissoras através de uma metodologia baseada na transferência dos fatores de desequilíbrios, grandezas estas, frequentemente presentes quando da ocorrência deste indicador de qualidade. Tomando por base este processo de análise para identificação da origem das VTCDs, estudos computacionais voltados para a avaliação de desempenho do procedimento proposto são conduzidos neste trabalho utilizando como caso teste o complexo HVDC do Rio Madeira. O artigo contempla aspectos gerais associados com o método de análise, com destaque a questão dos mecanismos que determinam as transferências dos fatores de desequilíbrio entre os enrolamentos de transformadores diante de situações factíveis de manifestação em campo. Através dos resultados das investigações são então exploradas situações representativas da manifestação dos fenômenos associados com as variações de tensão de curta duração, as quais são impostas, individualmente, no sistema elétrico à montante e à jusante do transformador, a partir dos quais, através da correlação entre os fatores de desequilíbrio e suas propagações, são avaliadas questões associadas com a efetividade do método utilizado.

Análise de Impactos na Qualidade de Energia devido à Inserção de Geração Distribuída na Microrrede do Campus da Universidade Federal de Itajubá

Fernanda A. Cardoso e Silva — 2022-11-30

The decentralization of power generation has become a trend towards the creation of more promising energy markets, focusing on penetration of renewable sources and smart microgrids structures. In this work, a case study is presented with the modeling and computational simulation of the 13,8 kV distribution network of the campus Prof. José Rodrigues Seabra from the Federal University of Itajuba by using the software OpenDSS - Open Distribution System Simulator, in the Daily mode. Three scenarios are proposed, with different installed photovoltaic generation powers, under two load conditions. The analyzes consider the flow of active and reactive power, power factor and voltage profile of the loads in the campus network, comparing the results of the three proposed scenarios, thus allowing to identify impacts on the quality of electrical power with the insertion of more photovoltaic distributed generation in this microgrid.

Model Predictive Control for Voltage Regulation of Standalone Self-Excited Induction Generator

Gabriel M. Cocco — 2022-11-30

This paper deals with a predictive current control strategy applied to voltage regulation in off-grid microgeneration systems based on self-excited induction generator (SEIG). A finite-control-set model predictive control (FCS-MPC) is used. This controller runs a discrete- time model to predict the future behavior of inverter currents for each switching state, then a control action is defined minimizing an appropriate cost function. Also combining proportional integral actions, the proposed control is capable of properly performing voltage regulation and harmonic compensation of positive, negative and zero sequence. The four-leg inverter is employed as DSTATCOM, this topology is a commonly used solution for powering standalone systems as it provides balanced three-phase voltages even under unbalanced load conditions. Simulations are presented to validate the proposed control technique, as well as to evaluate the performance of the system based on the IEEE 519-2014 and IEEE 1159-2009 Power Quality Standards.

Problemas de Medições em Analisadores de Energia Elétrica Devidos a Supra-Harmônicas Produzidas por Conversores Eletrônicos de Potência

José A. Pomilio — 2022-11-30

The article presents problems of harmonic identification in networks with the presence of power electronics converters with high switching frequency. It begins with a description of the standardized procedures for the operation of energy analyzers. The following shows how the presence of high frequency components can occur in currents and voltages signals. Finally, it is verified how such components can affect the correct spectral identification of the energy analyzers. Simulation results and field measurements are presented.

Uma estratégia de retrofit para monitoramento energético em sistemas prediais legados

Rubens A. Fernandes — 2022-11-30

Electric energy management enables the planning and efficient use of this input to improve competitiveness, sustainability and reduce costs for the final consumer. Along with this, the Internet of Things (IoT) paradigm promotes the emergence of solutions for remote energy monitoring, in order to enable strategies for this type of management. However, most of these solutions favor the disposal or replacement of outdated but still necessary elements. Thus, a strategy that allows the retrofit of legacy building systems to implement monitoring resources that help in energy management is necessary. In this sense, this work presents a strategy to enable energy monitoring in legacy building infrastructures using retrofit techniques. To validate the proposal, we developed embedded platforms for monitoring building electrical circuits in a power distribution board and developed a software application to integrate these devices and visualize the acquired data. The results present an alternative to improve energy management through remote monitoring and the maximum use of pre-existing resources.

Avaliação e Aprimoramento de Metodologias para Representação de CER no Problema de Fluxo de Potência

João Pedro Peters Barbosa — 2022-11-30

This paper discusses, through a review of the main methodologies, the representation of static var compensators (SVCs) in the power flow problem. One of the methodologies, consisting of a full Newton formulation of the problem, considers the thyristor’s firing angle as a state variable. The other methodology, also in full Newton formulation, proposes a model in which the SVC is represented considering the reactive power injected into the bus as a state variable. Furthermore, an improvement to the firing angle methodology is proposed in order to consider the voltage droop in the SVC’s linear region of operation. All methodologies are validated through the study of two test systems. The first system is a 3 bus tutorial system and the second is the well-known IEEE 118 bus system. The results presented validate the methodologies under study and the improvement in the equation of the linear region of operation for the first methodology.

Análise do Investimento Industrial em Energia Solar Fotovoltaica e Armazenamento de Energia – Estudo de caso da Bruning Tecnometal

Luydi Kunzler Botezeli — 2022-11-30

The studies related to alternative energy management with renewable sources of energy generation and storage are becoming increasingly a necessary and urgent agenda to face the exponential increase in energy consumption in the world according to environmental and sustainable requirements for the sector. With the proper management of the insertion of distributed energy resources in industrial consumers, several positive points arise regarding quality and reliability not only for the industrial consumer, but also for the distribution system and the environment. In this sense, this study evaluates in different scenarios the implementation of a photovoltaic solar energy generation and energy storage system in a metallurgical industry (Bruning Tecnometal), aiming at reducing electric energy expenses and seeking opportunities with behind-the-meter energy management. First, the current scenario of distributed energy resources is presented and the current scenario of energy contracting environments is analyzed. Then, the business models for energy self-production and energy storage are placed followed by the Bruning Tecnometal case study based on the company's energy reality.

Estudo Comparativo de Técnicas Utilizadas na Detecção de Faltas em Linhas de Transmissão pela Abordagem Baseada na Análise Espectral do Sinal

Frederico R. Cesário — 2022-11-30

This article presents the result of the comparison between three techniques used to detect the travelling wave signal for power lines fault location. The methods have in common the identification of the dominant frequencies of the traveling waves at the transmission line terminals as the transients propagate along the line. Among the three signal processing techniques considered, two are more traditional, the Short Time Fourier Transform (STFT) and the Wavelet Transform (WT). The third technique is the Hilbert-Huang Transform (THH), a new approach based on an elaborate adaptive method used for data analysis of non-linear and non-stationary processes. The three techniques have in common the spectrogram whose analysis provides signal parameters, among them, the instant of arrival of the traveling wave at the measuring terminal at the end of the line. The result of the comparison shows that the Hilbert-Huang Transform can accurately extract the arrival time of the traveling wave.

Avaliação do Impacto da Geração Eólica nas Interações Eletromecânicas de um SEP: uma análise baseada em dados de medição

André Mirandez Kernbichler — 2022-11-30

Obtaining electrical energy from wind emerges as a solution to environmental impacts and global warming corcernments, since its environmental impact is lower when compared to other forms of energy generation. However, this new iteration presents a dynamically different behavior, making the system operation increasingly challenging. Regarding the analysis of small signal stability, it is important to identify how the increase of wind generation participation in the electrical matrix can impact on electromechanical oscillations damping ratio, which are typical of a predominantly synchronous system. For this purpose, this work evaluates the impact of increased wind penetration in the interconnected system on electromechanical oscillations from signals sampled by phasor measurement units. The Prony’s method is applied to the transient portion of the system’s response to a disturbance, allowing the assessment of the increase in wind power impact, without the need to update the mathematical model representative of the system under analysis. Simulations are performed on the 39 bus system, evaluating different load levels and wind generation participation levels. The results show that there is an increase in oscillations damping ratio as there is an increase in wind generation participation, indicating a positive impact on this interaction.

Metodologia de Treinamento de Redes Neurais Artificiais para Detecção de Ilhamento de Geradores Distribuídos Fotovoltaicos

Luiza Buscariolli — 2022-11-30

The anti-islanding protection of distributed generators is typically performed by conventional protection schemes that monitor the magnitude and frequency of voltage signals. However, one of the main issues to setting these protection schemes is to identify and differentiate the magnitude and frequency variations of an islanding event from other disturbances that may occur along the system, such as voltage sag or swell. By using an Artificial Neural Network (ANN) based algorithm, it is possible to recognize existent patterns on the distributed generator voltage waveform, which makes possible to obtain an accurate response about islanding events. However, the ANN training process involves important issues such as the definition of the ANN architecture, the data window length, the sampling rate, and the selection of a representative training set for the analyzed power grid. In this context, this paper discusses the fundamental aspects for training an ANN used for islanding detection of photovoltaic distributed generators.

Desafios Atrelados à Geração Distribuída sob a Perspectiva da Distribuidora de Energia Elétrica no Brasil

Helen Velozo Vendrameto — 2022-11-30

The growth of distributed generation, especially from renewable sources, is a global trend, driven by increasing energy demand combined with environmental and economic issues. In this sense, the agents of the electrical sector, such as energy distributors, need to actively follow the evolution, due to the potential impacts of the connection of a new technology on a large scale. Distributors represent one of the most affected niches, since mini and micro distributed generation is directly connected to the medium or low voltage grid. In this scenario, several challenges present themselves to the utilities, categorized in this paper as: regulatory, technical, commercial, and market. From these perspectives, the objective of this paper is to present the main aspects and obstacles related to the theme, based on a review of the scientific literature.

Detecção de Perdas não Técnicas em Sistema de Distribuição Empregando a Transformada Wavelet

Almir Carlos dos Santos Júnior — 2022-11-30

Non-technical losses account for 7,5% of the energy injected into the Brazilian electricity grid. That losses cannot be fully passed on from distributors to consumers, which impacts on the profit of the companies, but also impacts in the responsible consumer, since part of this loss is prorated among regular users. The development of non-technical loss detection methodologies is important since, by discovering fraud, there is the possibility of revenue recovery and mitigation of other consequences. In this paper, two specific algorithmic solutions are proposed, capable of acting as a tool for extracting intrinsic characteristics of consumption patterns, which allow the detection of behavior associated with fraud. To develop both, a database with monthly consumption information in kilowatt-hour was created. The first technique makes use of discrete wavelet transform, so wavelet families were evaluated in order to define which one is the most suitable for implementing the technique. The Haar wavelet proved to be promising for the database in question, allowing a rate of correct answers in the classification of commercial customers around 77% and 86% accuracy in detecting fraud in the same customers. The second technique had a 79% hit rate for commercial customer ratings and a 78% fraud detection rate. As highlighted throughout the text, the complementarity of results for each of the techniques motivated the development of both.

Análise do Impacto das Fontes de Energia Elétrica no Setores Econômico e Socioambiental Através do Balanço Energético Nacional

André Nunes de Souza — 2022-11-30

This paper aim to develop an analysis from the data showed by a Brazilian Energy Balance known as (Balan¸co Energético Nacional ) and its relationship between the economics, environmentalism and governmental fields with its national electrical power sources. At the beginning of this paper, it is approached on how Brazilian Energy Balance has been build along the years as well as its historical load, standing as a responsibility of Power Research Enterprise known as (Empresa de Pesquisa Energética), and the methodology applied in order to acquire its data, to perform its calculations at its composition, as well as its accounting and disclosure. Finally an analysis is done from the data disclosed by Brazilian Energy Balance at the years of 2020 and 2021.

Princípios da Modelagem de um Inversor Trifásico com Filtro LC Conectado à Rede

Eubis P. Machado — 2022-11-30

In this work, as part of the activities developed in the scope of a R&D+I, the differential equations that express the dynamics of a VSI (Voltage Source Inverter) fed in current, supplied with input and output filters and connected to the network were studied. From well- established concepts of power electronics, the equations that characterize the VSI in the phase domain were defined. In order to overcome the discontinuities, the averaging operator concept was applied, resulting in a smooth model, but without a static operation point. Applying the Park transform to the averaged model in the phase domain, an averaged model in qd coordinates was obtained, which presents simpler equations and provides a static equilibrium point under steady state condition. Using the standard form of the state space, the equations were solved through the trapezoidal integration rule, whose results prove that the models are equivalent, highlighting the average models for requiring a reduced computational burden.

Modelos Matemáticos para Diferentes Tecnologias de Painéis Fotovoltaicos - Análise Comparativa

Mateus Campos Falcão — 2022-11-30

In studies to predict the generation capacity of photovoltaic plants with the occurrence of possible shading, the use of computer simulations of photovoltaic panels, based on mathematical models, to analyze the possible consequences stands out. This work aims to observe the best mathematical model according to the technology used. For this, three different technologies of photovoltaic modules were modeled and simulated through two mathematical methods to analyze which are the most reliable results corroborated by the real behavior of the panel.

Impacto da tarifa de Autoprodutor de Energia na Migração para o Mercado Livre

Cíntia H. Flesch — 2022-11-30

This article analyzed the potentization of results with self-production in the free energy market. From this, a case study of a consumer unit belonging to the A4 voltage group was developed, the company is under the concession of the distributor COPEL. Opportunities for savings in the self-producer modality, with the installation of a photovoltaic plant, were proved based on the utility's energy fee. Therefore, with the case study was concluded that the migration to Free Energy Market (ML) in the self-producer modality is able to boost the positive results of the consumer compared to the captive market.

Análise Dinâmica da CAMPUSGRID: Microrrede na Universidade Estadual de Campinas (UNICAMP)

Jesus Flores Huaman — 2022-11-30

Electric Microgrids are seen as the new trend related to the future generation and consumption of electric energy. As they are mainly composed of renewable energy sources with high penetration of electronic power converters, high levels of automation and control are necessary to guarantee operational stability. Therefore, this article presents the dynamic modeling of the CAMPUSGRID, which corresponds to a microgrid that has been built at the State University of Campinas (UNICAMP), and presents the analysis of its respective dynamic behavior. Through these studies, using the Typhoon HIL Control Center simulation software, it can be concluded that the microgrid has operational flexibility, capable of keeping stable even after the occurrence of events such as effects of renewable energy fluctuation, islanded mode transition, resynchronization and load variations.

Aplicação do Bat Algorithm na Otimização de Recursos Energéticos Distribuídos em Sistema de Distribuição

Adriana O. Mendonça — 2022-11-30

It is possible to notice the growing increase in the insertion of Distributed Energy Resources (DERs) in the Brazilian distribution system. Thus, this article aims to analyze the impact of allocation and optimal sizing of photovoltaic plants and battery banks through the Bat Algorithm optimization method. This simulation proposes a minimization of technical losses and voltage unbalance, moreover, the simulations were performed using OpenDSS® software and applied to the IEEE 34-bus distribution system. It is concluded that the insertion of DERs can effectively contribute to the reduction of technical losses with optimized allocation and penetration level.

Modelagem de Minirrede com Sistema Fotovoltaico, Diesel e Armazenamento de Energia Utilizando OpenDSS e Python

Gabriel A. Couto — 2022-11-30

This work presents the modeling and simulation of a hybrid mini grid with photovoltaic-diesel generation and an energy storage system. The studied network refers to the facilities of the Center of Excellence in Energy Efficiency of the Amazon (CEAMAZON), located at the Federal University of Pará (UFPA), enhanced by the project of an Intelligent System for the Efficient Management of Multimodal Electric Mobility. The model was created with OpenDSS software associated with Python, ensuring that the environment formed represents the electrical characteristics and operational resources of the grid. The study compared the data from the simulations with measurements from the real grid, verifying the parity between them.

Visita aos Conceitos de Modelo Chaveado, Médio e de Pequenos Sinais de um Conversor CC-CC

Eubis P. Machado — 2022-11-30

This paper, as part of the activities developed in the scope of a R&D+I, a review is carried out the fundamentals of switched, average and small-signal models of DC-DC converters, in order to provide clear and objective concepts. Starting from a PWM modulator, the concepts of the switching function and its Fourier series decomposition are presented to obtain the switched model of a converter. Based on the averaging operator, the averaged model and its stationary states are defined, which are the starting point for linearization of the converter. Writing the state and output vectors in the form of multivariable functions, the Taylor series is used to obtain the small-signal and linearized models of the converter. The results of the numerical solutions, their analysis and conclusions reveal the characteristics and applications of the models.

Dimensionamento ótimo de usinas solares com armazenamento em baterias para conexão em redes radiais por meio de otimização convexa

Max Chianca Pimentel Filho — 2022-11-30

Electricity production from wind and solar sources has increased considerably in recent decades. According to the website of the federal government of Brazil, 10.9% of the energy produced comes from wind farms and 2% from solar plants. However, the exploration of these sources is faced with an apparent limitation: difficulty in dispatching to keep up with energy demand. One of the solutions to this problem is the use of storage units to save energy in the period of generation surplus and to use it when there is a deficit. The objectives of this work are the determination of the nominal power of photovoltaic micro plants, located in specified points of radial distribution feeders, aiming to minimize the total losses of the system, as well as the determination of the capacity of the battery banks to be installed. The batteries will inject energy into the system, so that it does not need to use other energy sources when photovoltaic production is insufficient. For the implementation of the method, the energy of the total losses that was dissipated in the lines of the electrical system was used as an objective function, considering the period of one day. The calculation of the energy of the total losses will be carried out by dividing the daily curves of generation and consumption in 24 samples of one hour of duration, determining the energy of losses through the execution of 24 calculations of load flow. To determine the nominal power of generation at each node, the Lagrange multipliers method will be used, corresponding to the 1st order conditions of optimality. For the dimensioning of the batteries, the restriction was implemented, in which the power produced by the solar plants must be sufficient to supply all the energy consumed in the day (or part of this period). Thus, during the period of insolation, part of the generation will be consumed by the load and the rest will be accumulated in the banks, which will be consumed in the period in which there is no generation.

Modelagem e Controle de um Sistema de Excitação Estático de Gerador Síncrono Utilizando Conversor Buck

Raul E. Pivetta — 2022-11-30

This work presents a Wound Field Synchronous Generators (WFSG) terminal voltage control system modeling and design. The approach proposes a simple and robust static excitation system using a Buck converter powered from an external source. The calculation of the RMS value of the terminal voltages for control system feedback is replaced by obtaining the vd component of the three-phase voltages. Experimental results prove the maintenance of terminal voltages within the established limits.

Control Strategy for an Off-Grid Photovoltaic System in Haiti

Lendy Louidor — 2022-11-30

This paper proposes a control system for an off-grid photovoltaic system, which can be used to improve the electricity access in poor or developing countries. The PV system is composed of three independent closed-loop converters, connected to a common dc voltage bus. The objective of the proposed control system is to adequately control the power flow through these converters and the dc bus independently on the solar irradiation and the charge/discharge of the battery-bank while providing the power to the ac loads. To achieve this goal, the power injected to the dc link is monitored by using two integrated control loop that compute the difference between the input and output power levels to inject or to extract it from the battery bank under distinct operating points. Simulation results are included for an 1.6 kW PV system to validate the proposed control strategy.

Simulação de Transitórios Eletromagnéticos em uma Rede Real com a Aplicação de um Limitador de Corrente de Curto-Circuito Supercondutor Resistivo

Yan R. D. Rangel — 2022-11-30

With the growing demand for electricity, there is an expansion of the distribution network, with the insertion of new elements (capacitor bank, motors, etc.) and even energy sources such as distributed generation. Such insertions can intensify transient electromagnetic current phenomena in these networks, such as short circuits, motor starting and energizing of transformers and capacitor banks, being necessary analyzes to evaluate these events, as well as take action to mitigate/eliminate high currents. One of the promising alternatives is the use of resistive type superconductor fault current limiter (r-SFCL), due to its robustness and the intrinsic of material characteristic for such an application. In this context, this work analyzes the application of an r-SFCL in a real distribution network, by using ATPDraw program, and considering the electrothermal analogy for modeling the fault current limiter. The analyses were based on the 4 phenomena mentioned above, considering the performance of the r- SFCL against them. The results demonstrated the ability to reduce short-circuit currents by the proposed device, and selectivity against other events.

Carregamento Ótimo de VEs para Viabilizar a Participação de Estações de Carregamento no Mercado Local de Energia

Enielma Cunha da Silva — 2022-11-30

The increasing generation and flexible demand at a local level enable the development of a local market structure, in which its participants could trade with each other and/or with other market structures. Therefore, demands such as electric vehicle charging stations could take advantage of the flexibility in charging electric vehicles to participate in the market. In this sense, this paper intends to explore the optimal charging of electric vehicles to enable the participation of charging stations in the local energy market, considering that energy transactions in the market are constrained by the physical limits of the network. A mathematical model is proposed to represent the operation of prosumers and charging stations, as well as their commercial interaction in a local market structure. Charging stations' interests in the market are represented by an aggregator. The objective of the proposed model is to minimize energy purchase costs from the aggregator, with the coordination of charging as the control variable. The impact of this control was analyzed considering using the IEEE 33-node distribution system, and the results obtained show that this coordination enabled a better participation of the charging stations in the local market.

Algoritmo enxame de filas para localização ótima de turbinas eólicas

M. Firmino de Medeiros Júnior — 2022-11-30

The main objective of this work is to propose a new heuristic, inspired by the problem of optimal location of wind turbine queues, to solve this problem, allowing the incorporation of different restrictions, with low computational cost. From measurements obtained from equipment installed on anemometric towers, with the objective of prospecting promising locations for the implementation of wind farms, a wind map is prepared for a micro-region, with the help of software used for this purpose. Wind speed data are collected and, from these, annual averages are calculated to create the map. The mesh of points representing the area of the region, obtained by means of the software, has an adjustable sample rate, so that the mesh points can be obtained as close to each other as desired, allowing to admit a continuous function to represent the annual average wind speed variation (and, consequently, wind generation potential) with geographic coordinates. Thus, there will be no harm in adopting an optimization method that considers a domain with continuous variables. Mesh points (coordinates and attributes) are stored as a list in shape file (.shp) files, which can be opened with the help of the free software QGIS. Then the data can be read and reorganized into tables, to be processed by any other program. Thus, it is possible to build a function to measure the aptitude of each point for energy generation. From there, an objective function can be specified for an optimization problem.

Algoritmo Híbrido combinando a Têmpera Simulada e Busca Tabu para Localização Ótima de Geradores em Redes de Distribuição Radiais

Robson Thiago B. Rego — 2022-11-30

Metaheuristics have been effective in solving large-scale combinatorial optimization problems, in which there are many control variables, constraints and candidate solutions. The optimal location of generators in distribution networks, is one of those optimization problems in which the solution space is discrete and large. In fact, location is a part of the problem called optimizing distributed generation, which also covers the sizing and dispatch of generating units.The proposal is to combine simulated annealing (SA) and tabu search (TS), two established metaheuristics, in order to better adapt them to the specific application. The power losses in the feeder are taken as an objective function to be minimized. The networks are considered radial, without this implying a generality restriction, but because it is the predominant configuration. The expected contribution of the article is in the way in which the search for the optimal solution is carried out: instead of being free throughout the solution space, it is a search in neighborhoods of the current solution. As the SA is characterized by being a global search method and the TS, a local search method, their combination showed efficiency superior to that of the separate algorithms for almost all the different distribution networks to which it was applied.

Análise do Impacto da Inserção de Geração Distribuída Fotovoltaica na Qualidade da Energia Elétrica utilizando o software OpenDSS

Leandro H. Nogueira da Silva — 2022-11-30

This work aims to present an analysis of the impact of the insertion of photovoltaic distributed generation on the quality of electrical energy using the OpenDSS software, in a typical IEEE 13 bus distribution system. Thus, using the OpenDSS program and the IEEE 13 bus circuit, simulations were performed at a point in time, static mode, and in periods, in time series, evaluating different scenarios with and without the insertion of distributed resources. The main concepts involved will be presented, as well as the comparisons in three different scenarios, depending on the penetration level and location of photovoltaic distributed generation, the impacts on the steady-state voltage profile. This work proposes to explore the OpenDSS program, seeking within its functionalities to understand the functioning of a distribution network with the contribution of distributed energy resources. Besides showing that the insertion of DG in transmission networks must be studied and evaluated in order to mitigate as much as possible the problems that a distribution network may face.

A linear model for overload rerouting and testing switching measures for overload elimination by means of Relief Functions

A. C. Fernandes — 2022-11-30

Eventually, limit violations may occur during power systems operation, such as: overloads in transmission lines and power transformers, voltages at buses outside admissible range, etc. Thus, it is important to create ways to maintain the supply of electrical energy even in contingency operation situations, with fast and lowcost measures, keeping load restriction as the last control action. Corrective Switching is a technique capable of controlling the power flow in meshed networks by changing the network topology. The main advantage of this control tool is that it does not involve additional costs, since its implementation depends on maneuvers of elements already present in the network. In previous works, several techniques and methodologies were developed to reduce the computational effort needed to implement the technique, aiming its application in real-time operation. This work presents a new linear methodology to simulate overloads rerouting without changing the admittance matrix, avoiding extra computational effort for new factorization. Furthermore, the parameters calculated by linearization are able to build a relief function to identify switching variants capable to reconfigure the network in real-time through the technique of Corrective Switching.

Reforço em Linhas de Transmissão em Sistema com Alta Penetração Eólica

Monique Ribeiro da Costa — 2022-11-30

This paper presents a methodology to optimize reinforcements in transmission systems considering high wind power penetration represented by generation scenarios. The proposed methodology minimizes the total costs of the investments and guarantees a viable operation of the system. The increase in the capacity of the transmission lines, provided by the application of reinforcements in the appropriate places, allows a greater absorption of wind energy from the system, being able to take advantage of the benefits of renewables. The formulation considers an optimal active power flow and the relationship between the susceptance and the power capacity of transmission lines. The proposed methodology is solved with the linear programming technique. The IEEE 24 bus system is used to show the main concepts discussed in this paper.

Impacto da Resistência de Aterramento na Análise de Desligamentos por Tensões Induzidas Devido a Descargas Atmosféricas em Linhas de Distribuição

João A. C. Almeida — 2022-11-30

The assessment of distribution systems performance is a key factor to guarantee the continuity of energy supply. Hence, understanding the impacts that lightning can generate in this type of system is a matter of relevant importance. Therefore, this work aims to investigate the impact of grounding resistance on the distribution line lightning performance considering induced overvoltages. The present work is based on the theory proposed by Sune Rusck and later extended by J. O. Paulino. For this analysis, the Monte Carlo Method was also used in a computational routine to estimate the number of expected shutdowns of a distribution line. Thus, simulations were carried out with different values of grounding resistance and the number of shutdowns was calculated as a function of these values. According to the results, the value of the grounding resistance significantly impacts the expected number of shutdowns for a given distribution line.

Análise de desempenho de para-raios de ZnO sob diversos cenários de poluição utilizando Método de Elementos Finitos

Mellina M. Lisboa — 2022-11-30

Surge arresters are equipment of vital importance in the protection of electrical power systems, with the role of protecting transmission, distribution lines and electrical equipment in the face of atmospheric discharges, as well as maneuver surges in eventual maintenance, also reducing maintenance accidents. Thus, it is important to investigate the operating conditions of these equipment under different scenarios, whether under normal or polluted conditions. Therefore, a two-dimensional model of a 30 kV zinc oxide surge arrester was simulated, using the Finite Element Method, to obtain curves of the leakage current and the distributions of electric potential and electric field lines. The results show an increase in the quantities acquired as the level of pollution intensifies.

Influência dos Planos de Terra durante o Ensaio de Corona Visual em Arranjo Isolante para Linha Aérea de Transmissão de 500 kV

Adilton J. L. Pereira — 2022-11-30

Technical compliance of insulating arrangements of overhead transmission lines is traditionally validated by carrying out electrical tests in high-voltage laboratories. With limited technical and financial resources, these tests are mostly carried out in closed laboratory environments through a simplified single- phase reproduction of the transmission system. By normative recommendation, these single-phase test reproductions must foresee the influence of the adjacent phases of the original system through the positioning of panels acting as ground planes. Seeking to evaluate the correspondence between the critical electric field strength and the inception and extinction of visual corona voltage, as well as the distance factor for the ground planes, the article makes a case study of the positioning of these reflection planes and the arrangement mounting height. Using Finite Element Analysis, the simulation results show that the distance of the reflection planes can alter the electric field levels on the surface of conductors in the order of 18%.

Sistema para Testes Operacionais em Controles de Reguladores de Tensão: Uma Interface em Hardware Integrada ao OpenDSS

Cléber Cornely Bertuol — 2022-11-30

This work deals with a tool to assist in the tests of one of the main devices used to maintain the voltage level within the levels required by regulatory agencies in the electricity sector, the Voltage Regulators. Devices that are used along electric power distribution lines in order to keep the voltage level always close to the rated voltage, to avoid undervoltage and overvoltage. The developed system enables integration between the OpenDSS software and, through a hardware interface, transfers the physical values of voltage and current resulting from the simulation to the regulator control. Within the specifications defined for the tool, it showed results very similar to data extracted from software simulations. Proving to be a tool that can be well exploited for practical applications of simulated power flows in OpenDSS or by data extracted from a real network.

Configuração Modificada de D2VC (Dynamic Direct Voltage Controller) com Controle CC Baseado em Teoria PQ

Rafael W. P. Silva — 2022-11-30

This paper proposes a modified structure for the Dynamic Direct Voltage Controller (D2VC), here defined as Modified Dynamic Direct Voltage Controller (MD2VC) for application in distribution grids. An advantage of this controller structure is the online voltage compensation in distribution systems using a three-phase Voltage Source Converter (VSC) for the shunt side of the controller instead of three single- phase VSCs as in the case of the original proposed configuration of D2VC. In this case, the series VSCs are connected to the shunt VSC by only a single dc link, unlike the original configuration where, for each of phase, the series VSC is connected to the respective shunt VSC by the respective dc link. In this work, a control algorithm for dc-link voltage based on pq theory is proposed, dismissing the use of the adaptive hysteresis band current single-phase control strategy. This configuration of D2VC has the number of switches for shunt converters and dc links reduced. Simulation results carried out in time domain using PSCAD/EMTDC are presented to show the effectiveness of the proposed control.

Harmonic Analysis of High-Impedance Fault Experimental Current Waveforms Using Fast Fourier Transform

Ádrea Lima de Sousa — 2022-11-30

High impedance faults (HIFs) detection in overhead distribution networks have been a major challenge for utility engineers for a long time. The current flowing to ground path is so low that conventional protection does not detect HIFs. The problem becomes more critical when HIFs occur in rural feeders with many single-wire earth return networks, since the neutral protection is usually set above the normal unbalance current of the circuit to avoid its undue actuation, limiting the sensitivity of this protection for single phase-to-ground faults. Methods based on harmonic content analysis for HIF detection stand out for their simplicity, practicality, and ease of implementation. However, so that such methods do not present reliability issues, the harmonic indices thresholds need to be well adjusted, reconciling dependability and security of the HIF detection function. This paper presents a study of the harmonic components presents in the HIF current waveforms, obtained through experimental tests in a 13,8 kV distribution network, using Fast Fourier Transform. The study analyzed the harmonic components of the current waveforms recorded on a SEL-751 relay in 74 FAI events.

Influences of Electromagnetic Interferences on Two-Terminal Impedance-Based Fault Location Methods

Caio M. Moraes — 2022-11-30

Faults during transmission line operations are prone to occur, which reinforces the need for protection instruments to ensure the safety of facilities involved and, in case of power outages, to restore the energy supply in the least amount of time as possible. In this context, two terminal impedance-based fault locators are widely used in real installations, since they overcome limitations of single-terminal approaches. In this paper, a study is carried out to evaluate the performance of four classical fault location methods in a transmission system subjected to electromagnetic interferences (EMI). An overhead power line with 334 km is exposed to a hypothetical case of electromagnetic influeence due to inductive coupling with a 28" underground pipeline. The system is modeled using the well-known Alternative Transients Program (ATP) and phase-to-ground faults are simulated, varying fault resistances and locations, in order to obtain a parametric response. Results show that fault location methods based on series impedances, propagation constants and characteristic impedances underperform in situations which the EMI are neglected, presenting errors as large as 60 km. However, methods that do not rely on line parameters show significantly improved accuracy and great robustness with respectto external EMI, presenting fault location estimation errors of only 5%.

Revisão de Métodos de Estimativa do Comprimento de Rugosidade Aerodinâmica para Fins de Obtenção de Energia Eólica

Natália P. Saraiva — 2022-11-30

In this article, is proposed to identify the methods for estimating aerodynamic roughness length (z0) best suited to feasibility studies for the construction of wind farms. For that, a systematic review is carried out to filter the latest works that apply different methods to find z0 values. Identifying z0 for a specific surface is important to simulate the vertical wind profile and mechanical and turbulent fluxes estimation in the atmospheric surface layer. Must be considered those factors in viability studies for a wind farm, therefore impacting the calculation of energy efficiency. Morphometric and micrometeorological methods are listed, besides presenting works that have developed tables with z0 optimal values for different types of land. In the end, situations are presented in which each method has better applicability.

Optimal Installation of Wind Turbines to Minimize Energy Losses

Felipe Barros Dantas — 2022-11-30

Over the years, new methods have emerged in order to optimize the installation of wind turbines in distribution systems to meet the loads demand, reduce technical energy losses and avoid exceeding the voltage limits in the system. In this context, an algorithm for the optimal installation of wind turbines in radial distribution systems is presented here. The Genetic Algorithm and the Cuckoo Search are used as optimization methods and, to calculate the power flow, the Sum of Powers Method is used, respecting the voltage limits imposed by ANEEL and not exceeding a 20% wind generation penetration. The segmented annual load curve was used and it was considered that the load curve in all buses and the feeder are the same, as well as the wind speed curve. The analysis of the results has shown that the proposed algorithm has been able to install wind generators reducing the energy losses as well as estimating the investment value of installation and operation of the turbines. The algorithm was applied to three radial test systems (36, 134 and 1080 buses) and was successful in the case studies.

Modelo Inteligente Utilizando Grafos para Previsão da Potência Gerada por Módulos de Painéis Fotovoltaicos

Bruna Rodrigues Vidigal — 2022-11-30

The growth in demand for electricity in the world has intensified the alternative use of renewable energy sources such as solar energy. Solar panels are structures composed of photovoltaic cells, responsible for absorbing solar radiation and transforming it into electrical current. Photovoltaic Systems (PV system) performance analysis mainly helps to reduce energy loss and maintenance costs. However, most existing solutions for performance analysis need technical knowledge and often neglect spatial and temporal dependencies. In this paper, it is proposed a spatial-temporal graph neural network with the objective of automating the analysis of the PV system functioning. The classic technique using statistical models of time series is used for comparison purposes. The model adjustment was performed to predict future values, and performance metrics considering the model error were used to define the best fitted model. The model using neural networks and graphs presented better performance than the classic one, showing that considering the structure of the system is very relevant in the performance analysis.

Impacto da Geração Distribuída por Fonte Fotovoltaica em uma Rede de Distribuição e seu Sistema de Proteção de Sobrecorrente

Claudio P. S. Filho — 2022-11-30

The different peculiarities of distribution systems added to the variability of generation and integration by sources of distributed generation, bring with them challenges for the adaptation of the entire network and, mainly, for its protection systems. In this context, this work analyzes the impacts caused to the protection system of a distribution network after the integration of distributed generation by photovoltaic solar source against different test scenarios for the insertion of distributed generation and the occurrence of faults. The results demonstrate the influence of the variability of the integration of distributed generation on the voltage profile of the distribution system and on the protection actuation depending on the location of the generation source, the fault location and positioning of the relays. reverse fault and consequently non-compliance with the basic requirements of the protection system.

Perdas não técnicas em irrigantes da região rizicultora do Rio Grande do Sul

Vanessa G. Vieira — 2022-11-30

Non-technical losses (NTL) are a component of energy losses associated with energy theft or irregular billed energy measurements, including in rural areas. We developed a methodology that address the specificities of consumption with irrigation for rice crops, and use information from historical data of consumer units and associating with the size of the crop, energy demand, local topography and other pertinent information. Such information influenced and helped in the grouping (clustering) of consumer units composing their consumption profiles and cultivation areas. Clustering facilitated the association of rice growing areas with the corresponding consumer unit, and this also facilitated the definition of some rules for classifying consumer units with NTL potential. This study employs a large mass of input data, not only the energy consumption of the irrigation consumer units, but also phenological characteristics of the plant, type of irrigation, meteorological information, cultivated area and soil permeability. Based on the analysis of consumption historic from 2018 to 2021, the proposed artificial intelligence system generated as a result a list for planning inspection during the RGE-Sul’s 2021/2022 harvest. The result of inspections may provide an important return as to the assertiveness of the choice. This result may also suggest a possible restructuring of the methodology in the use of the concepts of RNA, KNN and Random Forest. The methodology for automated analysis reached results with high adherence with the manual process currently applied.

Abordagem para Redução dos Indicadores Individuais e Coletivos em Conjunto de Consumidores UC Irrigantes

F. G. Fabrin — 2022-11-30

The present work presents an approach for the reduction of collective and individual indicators for a Set, which serves urban and rural Consumer Units (UCs), where the rural ones have irrigators with central pivot served with A4 voltage class Green tariff. This methodology is based on the average daily values of the indicators and consumption for the definition of an Energy Storage System - SAE and Photovoltaic Plant - UFV. Irrigating rural UCs tend to violate the limits of the indicators defined by ANEEL. In this way, an SAE was designed together with UFV, so that it can be installed at strategic points in order to reduce the indicators, which are currently causing high amounts of fines. The characteristics of SAE and UFV were defined through the energy consumed in rural and urban areas separately, together with the value of the Maximum Duration of Continuous Interruption per consumer unit - DMIC. With this, it is intended to reduce the indicators to values lower than those established. It was concluded that in 19 years the amount invested is recovered.

Utilização de um banco de baterias para regulação de frequência de uma microrrede aplicando técnica de controle LQR

Gustavo C. Costa — 2022-11-30

Even though Brazil is a reference in renewable energy participation on its electric matrix, there is still a motivation to diversify this matrix, for three reasons: water resource dependency; abundance of energy resources and maturity of technological development. With the reduction of generation and storage system costs, there is a trend to increase other renewable resources participation, beyond the hydraulic such as wind and solar energy. Nonetheless, related to their construction characteristics, wind and solar technologies are unable to naturally add inertia to the electric system. Thus, the large renewable energy insertion presents a challenge to electrical system operation. Therefore, it’s necessary to develop new alternatives to supply the disturbances caused, in particular, to the frequency range of the grid. In this context, this work proposes a LQR controller technic applied on a Battery Energy Storage System (BESS) for primary frequency regulation. Besides that, a dead band is used with the purpose that the system acts only on major disturbances. As a way of comparison, the Droop control is simulated for the same model. The simulations were performed using the Matlab Simulink® software.

Fundamentos da Proteção de Geradores Síncronos contra Correntes Desbalanceadas

Letícia R. Almeida — 2022-11-30

This work evaluates in detail the protection performance of synchronous generators against unbalanced currents. For this, a simplified power system composed of a generating unit with smooth poles, connected to a remote system through a step-up transformer and a dual circuit transmission line, is modeled in the EMTP-RV program. The results obtained show how the amplitude of the negative sequence current is influenced by the type and severity of unbalanced conditions, such as open phase and asymmetrical short circuits. Also, the simulations allow us to visualize how this current is linked to the energy accumulated in the generator rotor structure over time, and to the operating times of the ANSI 46 function, which seek to respect the thermal withstand limits defined by the constructive aspects of the machines.

Implementação de um relé virtual de proteção diferencial de transformadores: Avaliação de cenários de curtos-circuitos, inrush e saturação de TCs

Ramon J. N. Silva — 2022-11-30

The transformer is one of the main pieces of equipment in the electrical system, being of vital importance for the delivery of electrical energy to consumer centers. Therefore, care must be taken, and these equipment’s must be carefully protected. One way to protect it against internal faults is to apply the differential protection function. The response of this function must be carefully analyzed for internal short circuit conditions, for which it is designed, and for conditions that can cause it to act improperly, such as external short circuits, current transformer saturation and transformer energization. Thus, in this work the implementation of a virtual transformer differential protection relay to evaluate such conditions is presented. For this, Matlab software is used to elaborate all the processing steps that make up a numerical relay. The main results are presented and confronted with the state of the art related to the theme.

Análise de desempenho de um modelo de geração de alvos de fiscalização de perdas não técnicas

Wesley Biffe — 2022-11-30

The electrical system is made up of the generation, transmission and distribution sectors, these sectors having losses that can be divided into technical losses and non-technical losses. The objective of the present study is to analyze the performance of a prediction model and identification of outliers referring to non-technical losses. The methodology is based on the use of SPSS Software that, through the data mining process, performs a search for patterns, enabling the appointment of consumers in a situation of probable irregularity. Through the analysis of the assertiveness of the current model, it is sought to improve it and create a new predictive model in order to achieve more accurate results.

SAIR: Sistema Automatizado de Iluminação e Refrigeração

Jhennifer F. dos Santos — 2022-11-30

With the increase in energy tariffs throughout Brazil, there was a great concern among public public institutions with the impact of these readjustments in the total budget making it necessary to search for new ways to generate savings in energy consumption. From this scenario, it was developed the Automated System for Lighting and Cooling (SAIR), based on the concept of Internet of Things (IoT), using wifi connection in the system modules, access to the cloud and a web interface that allows users to remotely control the lighting and climate control of the environments of a public institution, aiming to provide the reduction of energy consumption energy consumption, besides the financial savings and the remote monitoring of these equipments. Besides, the cost to produce a SAIR module is low, and because of this its investment has a fast financial return, which favors its implementation in large buildings. large buildings.

Avaliação da vida útil de um transformador da subestação de uma usina eólica: Um estudo de caso no nordeste brasileiro

Matheus Marini — 2022-11-30

This article performs correlation analyzes between the aging of a transformer with forced ventilation of a northeastern wind farm in Brazil with the variation of wind speed. The main objective is to verify if the power oscillation existing in the wind farms accelerates the degradation of the transformer, thus identifying a factor of correct dimensioning of the transformers, preventing high maintenance and operation costs of the companies that generate this type of energy. Such verification’s are carried out using international standards with equivalence in the country, that consider apparent power and ambient temperature as the main factors for calculating aging. The results show that the temperature of the hottest point of the winding can reach approximately 130 degrees celsius, which reduces the lifespan of the transformer. In order for the transformer to operate for 35 years, this article concludes that the power of the substation transformer must be about 0.8 of the rated power of the wind farm.

Análise de Alternativas para Suprimento de Energia com Grupos Geradores e Geração Distribuída durante Desligamento Programado

Angélica Felipe da Silva — 2022-11-30

The decrease in DEC and FEC in eventual network works is something that energy concessionaires have studied a lot these days, with the increase in the rigidity of the electric energy regulatory body (ANEEL) with regard to fines on energy quality, it is It is very important to optimize these scheduled stoppages in order to reduce the indicators, which are therefore financially linked to the electricity distribution companies.It is possible to dimension and couple groups of generators in networks that would be under-supplied, creating islands of consumers in order to optimize the concessionaire's indicators. With the help of distributed generation and battery banks, it is possible to optimize the supply costs of these islands. For that, a case based on an adapted 123 Node Test Feeder distribution feeder was used. It was incorporated in the network telecommunications switches, fuses switches, distributed generators and auxiliary systems (battery bank and diesel generators). Through the analysis scenarios, considering a generation system with photovoltaic systems and storage systems was possible to determine how differences and possible optimizations in the circuit. In the scenario (GD + photovoltaic) it optimizes the fuel consumption necessary to supply the island, but there is still the cost of operating the generator of the same capacity as in the solution without photovoltaic generation at the connection point with the lowest system loss. In the scenario (GD + photovoltaic + storage) it is possible to use a group of smaller generators, thus optimizing costs both in fuel and in the availability of a less powerful generator.

Panorama 5G para o Setor Elétrico: Requisitos, Aplicações e Prova de Conceito

Joyce M. Siqueira — 2022-11-30

Within the Smart Grids concept, the development of wireless network technologies has been configured as an alternative to wired infrastructure networks. However, the high criticity stablished in the network requirements for the power system applications makes existing wireless networks not always suitable. In this context, the 5th generation wireless network, 5G, provides low latency and high reliability, which makes this technology promising for the electricity sector. This paper presents a survey of the requirements of the electric power system applications that can benefit from the 5G technology. In addition, a Proof of Concept performed in the Enel’s distribution network is presented, which aimed to improve connectivity between devices, evaluating the 5G performance in this network.

Utilização dos protocolos ESP-NOW e MQTT para monitoramento e interação com sistemas industriais

Lucas H. Santos — 2022-11-30

This article describes an implementation of an automation system for engines that uses the ESP- NOW and MQTT (Message Queue Telemetry Transport) protocols to send data. The main of the created system is to avoid the loss due to eventual objective in the communication data network. For this, the developed system can use two network topologies: Mesh and Ad Hoc. As a form of control, they were performed to control water and control a control system, where a run-level control system was performed. After the tests carried out, the objective was that the system reached its main use and is its use in the industrial sector.

Predição das Componentes de Clarke via Interpolação Polinomial de 1º Grau com Base Newtoniana Aplicada na Estimação Digital de Frequência

Fábio K. Schons — 2022-11-30

The electrical frequency is a parameter of great importance for the full functioning of the Electric Power Systems (EPS), influencing the operation of the equipment and the power quality supplied. This work presents an innovative method for estimating digital frequency in EPS. The estimation technique is based on the analysis of the network voltage waveforms, which are decomposed into their components a and ß through the Clarke Transform. The future values of the a and ß components are predicted through 1st degree polynomial interpolation with Newton’s base. From these values, the frequency of the network is then estimated as a function of the angle resulting from the product between the signal of the Clarke complex and that given by the prediction of the components a and ß. The proposed method was tested for voltage signals with step, ramp, exponential and damped sinusoidal frequency variations. Cases were also tested for signals with amplitude variation. The methodology was evaluated in terms of convergence time and minimum and maximum errors before and after convergence, showing that the proposed technique has great precision and robustness for the simulated situations.

Análise da Viabilidade Econômica no Setor de Transporte com a Introdução de Veículos Elétricos em Órgãos Públicos

Patrícia G. Dallepiane — 2022-11-30

An economic and efficient transport contributes to the development of the economy and the reduction of expenses in the logistics of organizations. Electric vehicles provide a new mobility alternative, due to the advantages related to the reduction of traffic noise, reduction of pollutant gas emissions and because they present lower costs during their operation compared to traditional vehicles. In addition to seeking to build a sustainable economy through recharges carried out by renewable energy sources. Thus, the objective of this article is to carry out an analysis of the economic viability with the insertion of electric vehicles in public agencies. The present study tends to develop an economic evaluation with the supply and maintenance of fleets and to point out the benefits to the environment regarding the replacement of combustion vehicles by electric ones. The study is based on information collected in a City Hall located in the State of Rio Grande do Sul. The analysis of each criterion aims to demonstrate that the process of replacing the vehicle fleet can be a viable alternative for public organizations focusing on the operation of vehicles, due to the savings generated during their use and the reduction in the emission of pollutants.

AVALIAÇÃO DOS IMPACTOS DE HARMÔNICOS DE SEQUENCIA NEGATIVA E ZERO EM MOTORES ELÉTRICOS CLASSES IE2, IE3 E IE4 COM LIGAÇÕES DELTA E ESTRELA

Iago R. M. R. Morais — 2022-11-30

The presence of harmonics in electrical systems results in increases in consumption, temperature, and a reduction in the useful life of electric motors. Based on the above, the impact on these parameters could be reduced in the star connection (380 Volts), where a lower input current is obtained and with which the negative effects could be reduced. This work carries out an evaluation of the impacts of the 2nd and 3rd harmonics of negative and zero sequences in electric motors classes IE2, IE3 and IE4 connected in delta and star. The results show that the temperature is not affected to a great extent by the motor terminals connection, presenting small differences for the 3 analyzed motors.

Estudo da densidade de descargas atmosféricas no Estado do Acre utilizando dados da rede de detecção Vaisala GLD-360

Eurico F. Melo Leite — 2022-11-30

The Amazonian territory is known internationally as a region with a high incidence of lightning strikes. To understand the behavior of this natural phenomenon, it contributes a lot to the development of protection systems, which start to be better dimensioned and strategically distributed, safeguarding the integrity of structures and safety for living beings. In order to investigate whether the current assessment of the exposure risks of these systems, suggested by the Brazilian standard NBR 5419/2015, is reliable for Acre’s state, a study of the density indexes of lightning to ground (Ng) was carried out for this region, during the period 2016-2019, using data provided by the foreign detection network Vaisala GLD-360. The Ng parameter measures the quantity of discharges per square kilometer that reach a certain area in a period of one year, and is crucial for an assessment of exposure risks of protection systems. Through the geoprocessing tool QGIS 3.14.0, average Ng values were found to be much higher than those suggested by NBR 5419/2015 for all Acre’s cities, which raises the need to consider a revision of the referred document, and a proposal to update these indexes for the aforementioned region.

Estimativa de redução de emissão de CO2 pela inserção de UFV para cidades isoladas na Amazônia

Aline Santana Gallina — 2022-11-30

Most of the cities isolated from the national interconnected electrical grid are located in the brazilian Northern Region, and are mainly supplied by thermal power generation, despite representing the main contribution of the electricity sector to greenhouse gas emissions. the isolation occurs mainly because of environmental issues and financial constraints. In Acre, six thermal units supply three isolated cities, with a total installed capacity of 48,34 MW. Due to the potential for renewable energy generation and the high solar irradiance at the sites, the potential for photovoltaic generation in the municipalities of Cruzeiro do Sul, Feijó and Tarauacá was studied considering their respective load curves and solarimetric data of the region, which were provided by stations close to the locations, using the RadiaSol 2 software. Generation systems were proposed for each municipality considering 400W panels, varying the photovoltaic penetration rate with 100%, 75% and 50%. Computer simulations were used to estimate the environmental benefits of the possible replacement of the energy source was estimated based on the reduction of CO2 emissions calculated with the bottom-up method. The quantity and total area of the panels and the cost of implementation were also estimated. The carbon dioxide emissions of the photovoltaic power generation were much lower than those of thermal power generation with diesel fuel. They decreased between 94% and 47% compared to thermal power generation in the three cities. Despite the high costs photovoltaic plants, the investment in hybrid power generation systems is justified by the environmental benefits.

Otimização de Redes Coletoras de Parques Eólicos Utilizando Programação Binária

Fellipe A. L. Oliveira — 2022-11-30

This work proposes an optimization model for the design of wind farms collector networks, in order to minimize construction and losses costs over a planning horizon. A model found in the literature is reproduced and improved by additional contributions made in this work. The results analysis shows that competent solutions are obtained and that additional savings are achieved by using the proposed model.

VOLTAGE VARIATION IN HIGH EFFICIENCY MOTORS: A TECHNICAL AND COMPUTATIONAL APPROACH

LAURO CORREA — 2022-11-30

Voltage variation is a silent enemy in electrical systems and with considerable effects on electric motors. In this work, technical experiments were carried out to evaluate the impact of this disturbance in electric motors classes IE2, IE3 and IE4, then computational simulations were carried out using genetic algorithms to predict the temperature of the analyzed motors. The results showed how the voltage variation produces deviations in consumption and temperature, while excellent temperature approximations were obtained by computational techniques.

Privacidade dos dados dos usuários na medição inteligente: analisando o desempenho e a viabilidade

Tiago Bornia de Castro — 2022-11-30

Smart grids allow more connectivity between the end-user and the electric utility. Residential meters are replaced by smart meters, enabling near real-time communication between customer and company. The metering data serves to billing, monitoring, and service delivery. However, the interception of a malicious entity, or the misused by the utility, could expose customer privacy. With this comes the need to protect the privacy of end-users. Literature solutions discuss techniques such as data aggregation, homomorphic encryption, trusted third- party service, and blind signing to solve this problem. This article performs a qualitative and quantitative comparison of measurement models focused on operations data, considering the privacy aspect of user data. As a result, the blind signing model excelled in the security analysis and had 50% lower CPU usage than the partially homomorphic encryption model..

Desafios de Técnicas de Localização de Faltas em Sistemas de Transmissão com Compensação Série

Raphael L. A. Reis — 2022-11-30

In this paper, the impacts of fixed series-compensated transmission lines (TL) on classical phasor-based fault location techniques are evaluated, in order to identify the typical challenges faced by such methods. To do so, several Alternative Transients Program (ATP) fault simulations were carried out in a 500 kV/60 Hz transmission system, which is modeled considering parameters taken from a real Brazilian network. Comparative analyses are performed with uncompensated TL. From the obtained results, low frequencies superimposed to voltage and current signals due to the subsynchronous resonance affect the performance of phasor estimation filters and consequentely, fault location procedures. Therefore, the development of solutions that can be immune to such subsynchronous frequencies is needed.

Análise dos Métodos de Proteção Anti-ilhamento em Sistemas com Múltiplos Geradores Distribuídos

Maria Eduarda Le˜ao Ramos Vicente Ribeiro — 2022-11-30

Due to the growth of renewable resources in electrical power systems, it is essential to study and analyze possible events that impact the safety of the system. One of these abnormal events is the islanding of distributed generators. The islanding consists of an isolated operation of distributed generators and their respective loads, hence, part of the system is disconnected from the utility, but still in operation. This operation can bring numerous negative consequences: both for the electricity grid and its equipment, as well as for operators and users of the network. It is of great importance to adopt effective and safe island detection methods. Therefore, this work aims to analyse and evaluate common methods of anti-islading protection considering multiple distributed generators in low voltage, from the simulation of an IEEE 13-bus system with two wind farms and one photovoltaic power plants using MATLAB/SIMULINK.

Impacto da Geração Distribuída no Equilíbrio Econômico-Financeiro das Distribuidoras de Energia Elétrica

Thayce Luan Souza Bastos — 2022-11-30

The increase in the Distributed Generation (DG) insertion presents many challenges for electric power Distribution Companies (DISCOs). Particularly, the utility grid is used by small producers as a storage system, injecting surplus energy at the time of high generation and low consumption, and reversing the flow when the opposite occurs. This dependence on DISCOs occurs because the energy self-sufficiency of consumer units is still considered economically unfeasible, given the high cost of electrical storage technologies. However, in Brazil, the increased DG insertion has become a financial risk for distributors, as fixed costs are recovered through volumetric tariffs. Therefore, the DG diffusion can affect the DISCOs Economic-Financial Balance (EFB) in the short and long term. However, the distribution companies do not have systematic analyzes that indicate how the increase in the DG insertion has impacted their EFB. Therefore, in the present article a qualitative analysis of the aforementioned impact is presented, considering technical and economic aspects. Based on this analysis, it will be possible to establish indicators that allow the quantification of impacts according to the DG penetration level. The results obtained so far provide valuable information for a distributor to adopt strategies in the DG management and in the negotiation with the regulatory agency at the tariff revisions period.

Otimização Robusta Aplicada ao Planejamento da Operação de Longo-Prazo de Sistemas Hidrotérmicos

Caio Monteiro Leocádio — 2022-11-30

One of the main challenges in long-term operation planning of hydrothermal systems is the uncertainties treatment related to inflows in hydroelectric plants and their reservoirs. This work proposes a methodology based on Linear Adjustable Robust Optimization to allow the tractability of infinite uncertainty scenarios in operation planning problem. To assess the applicability of method, case studies are simulated using a real system based on Brazilian electrical system. The results indicate the feasibility of applying the proposed methodology and shows a comparison of total operating costs, generation evolution and storage trajectories in reservoirs with other deterministic and stochastic programming approaches, where the proposed model presented better performance in definition of policy operation that implies lower costs in face of all possible scenarios of water inflows that may occur later.

Avaliação da Proteção de Geradores Síncronos contra a Perda de Campo nos Planos R-X e P-Q

Lucas Manoel Costa — 2022-11-30

In this work, it is proposed a comparative evaluation between two protection schemes for synchronous generators against loss of excitation, based on the R-X impedance plane and the P-Q power plane. For this, a power system modeled in the EMTP-RV software was used to simulate cases of total and partial field loss, with different pre-disturbance load conditions of the generator, and considering the operation of generators in parallel. The results show that the traditional scheme is still a good tool in terms of operation time and reliability. However, the protection based on the P-Q plane is more flexible in terms of its setting.

Modelagem de Fonte de Potência Controlada no ATP/ATPDraw: Um Desenvolvimento Alternativo para Estudos de Fluxo de Potência

Felipe Lopes — 2022-11-30

This paper presents a tutorial on the implementation of a simplified controllable source in the Alternative Transients Program (ATP) environment, which is capable of representing electrical energy resources and loads with settable active and reactive power. The model is developed in the ATPDraw platform, taking advantage of the MODELS programming language and Transient Analysis of Control Systems (TACS) elements. To address the proposed source potentialities, examples are presented, including a comparison with a detailed photovoltaic ATP/ATPDraw benchmark power plant model. The results demonstrate that the proposed source is accurate and reliable for stable voltage conditions, allowing the ATP/ATPDraw to be easily used as an alternative platform for power flow studies, facilitating the representation of loads and inverter-based resources in steady-state conditions.

Análise de Campos Eletromagnéticos em Linhas de Transmissão Paralelas utilizando Modelo Bidimensional no Software FEMM

Roberto J. Cabral — 2022-11-30

The present paper evaluates the electromagnetic field induced by the high voltage overhead transmission line of 132 kV, by numerical modeling in FEMM software using ¨finite element method magnetics¨. Several case studies are considered, where simulations are proposed under nominal conditions in 132 kV transmission lines, for typical structures in Argentina. The simulations carried out in relation to the study of distribution of Electric and Magnetic Fields in the right of way for 2 parallel overhead transmission lines at 132 kV, both in rural and urban areas. The results obtained will be evaluated based on what is established by current regulations.

Retificador Unidirecional Multinível com Regulação Automática das Tensões

Wilmar A. P. Castiblanco — 2022-11-30

Multilevel rectifiers allow improving the system performance by reducing the harmonic content of synthesized voltages, which leads to minimizing the size and weight of the grid interface filters. Alternatively, the use of unidirectional PWM rectifiers is particularly interesting in situations where there is nonregenerative operation, since it is possible to operate with fewer active switches. This work proposes a unidirectional five-level rectifier which reduces the number of components needed and allows the automatic regulation of floating capacitors voltages, without employing complex control techniques with sensors and/or additional circuits. In addition, the proposed rectifier requires devices with lower reverse voltages and, consequently, the number of components in series can be minimized. Simulation results demonstrate the validity of the proposal.