Proposição de implementação de medidas mitigadoras para redução do nível de curto-circuito em estudo de superação de disjuntores

Abstract

The constant growth in electrical power demand requires careful planning to expand the generation power plants and the transmission lines while maintaining the efficiency, safety, and reliability of the electrical system. The integration of new projects introduces operational challenges to the electrical grid, such as increased power flows and short-circuit currents. In some instances, these currents may exceed the rated capacity of circuit breakers, resulting in their being overstressed. Therefore, it is imperative to assess the equipment’s rated withstand capability against the fault currents in the circuit where it is installed. The Brazilian Electric System (SEB) currently confronts significant challenges, particularly concerning high levels of short-circuit currents. This is especially notable in the electrical area of Rio de Janeiro, which contains numerous substations where circuit breakers have been overstressed. This situation has constrained the expansion of the system. In this context, this study entailed comprehensive simulations of the Rio de Janeiro area to determine short-circuit currents within the simulation network. To conduct these simulations, we utilized the computational program Simultaneous Fault Analysis (ANAFAS) and conducted an extensive investigation of circuit breakers being overstressed under actual electrical system conditions. To address the issue of circuit breakers being overstressed due to high fault currents, we also present the principal mitigating measures commonly employed in Brazil and worldwide. The primary objective of this study was to research structural solutions for implementation in the Rio de Janeiro area, thus replacing the temporary operational measures that have been previously utilized. Additionally, the study estimated the necessary investments for implementing these definitive solutions. The significance of this work extends to the practical application of the proposed measures within the substations of the Rio area, considering the current analysis timeframe and the future configuration of this electrical system.