Study of the influences of current limiting reactor on the circuit breaker breaking capability

Abstract

Northwest China is rich in energy resources including the renewable energy, therefore the power supply in some areas of the northwest power grid is in high density, which leads to the fact that the short-circuit current is too large and the series reactor might be used to suppress short circuit current. However, the series reactor application is also likely to leads to the slower decayed DC component and the higher DC component percentage in the total short circuit current and thus affect the actual breaking capability of the circuit breaker. Based on the probable practise of WB power grid, the impacts of series reactors on power system short-circuit current characteristics, especially the DC component and current zero offset are analyzed, and the breaking ability and making capability checking standard of circuit breaker are evaluated. Following conclusion are obtained: when the series reactor is installed to restrain the short circuit current, the breaking capability of the circuit breaker should be verified by the total short circuit current RMS.