Fundamentos da Proteção de Geradores Síncronos contra Correntes Desbalanceadas

Abstract

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.