Restrike characteristics of vacuum circuit breaker in its opening process under DC voltage

The restrike of vacuum circuit breaker during the breaking process causes overvoltage and intensifies the insulation deterioration of high-voltage equipment. To solve this problem, the vacuum breaker aging test method and the restrike characteristics are researched. 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 restrike, the wavefront steepness of the breakdown voltage, and the breakdown duration. The number of restrike during the breaking of vacuum circuit breaker decreased and the duration of the repeated-breakdown arc increased with the increased contact spacing of vacuum circuit breaker. As the loop current of the test system increased, the number of restrike during the breaking of vacuum circuit breaker, the wavefront steepness of the breakdown voltage, and the duration of the restrike arc increased. As the inrush current amplitude increased during the closing of vacuum circuit breaker, the number of restrike and the duration of the repeated-breakdown arc during the breaking of vacuum circuit breaker increased. 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.