Resumo:
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.
