Rebreakdown Characteristics of Vacuum Circuit Breaker in its Breaking Process under DC Voltage

The repeated breakdown of vacuum circuit breaker during the breaking process causes overvoltage and intensifies the insulation deterioration of high-voltage equipment. The work studied the repeated breakdown of vacuum circuit breaker in view of the issue. A withstand voltage test platform of 40.5-kV vacuum circuit breaker was established to obtain the effects of the contact spacing and loop and inrush currents of vacuum circuit breaker on the number of repeated breakdown, the wavefront steepness of the breakdown voltage, and the breakdown duration. The number of repeated breakdown during the breaking of vacuum circuit breaker decreased and the duration of the repeatedbreakdown arc increased with the increased contact spacing of vacuum circuit breaker. As the loop current of the test system increased, the number of repeated breakdown during the breaking of vacuum circuit breaker, the wavefront steepness of the breakdown voltage The results provide a theoretical basis and data support for the preventive test of 40.5-kV vacuum circuit breaker and the optimization of the withstand voltage test.