Experiment research on post-arc current in DC vacuum circuit breakers

The current zero period of vacuum arc determines the breaking performance of vacuum circuit breakers, and post-arc current is one of main parameters of current zero period. DC vacuum circuit breaker is one practical solution to solve the bottleneck of DC transmission circuit breaker. It is difficult to measure the post-arc current, when artificial current zero method is used to break the DC short circuit fault, because the current drop rate is very large. In this paper, the experimental circuit is built, and the post-arc current with different commutation parameters is measured by the resistance-transfer method. The results show that the peak value of post-arc current is related to arcing time and the drop rate of current zero period. Either arcing time or current drop rate of current zero period is larger can cause a higher peak value of post-arc current. The experimental waveform also validates the phenomenon that high-energy particles penetrate the sheath at the beginning of sheath development.