Reliability Analysis of Pre-insertion Resistors for EHV/UHV SF6 Circuit Breakers

Pre-insertion resistors (PIR) is used to suppress the inrush current and transient over voltages in the closing of circuit breaker, and its special application results in a high failure rate. This paper first takes 750 kV AC filter banks circuit breaker PIR as a model, and three typical defects of PIR are simulated by COMSOL. Then, according to the simulation results, the defect analysis methods of dynamic resistance fitting method, and PIR current impulse, PIR voltage impulse are presented. Finally, the combined circuit breaker control strategy which combining the series of PIR circuit breaker with the phase-selecting closing device is proposed, and the optimal combination strategy is given through PSCAD.