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

Abstract

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.