Diagnosis of Post-Arc Residual Plasma in Vacuum Breaker

The residual plasma in the gap between the anode and cathode has an important influence on the recovery characteristics of the medium after the arc current zero in the vacuum arc extinguishing chamber. A diagnostic system for post-arc residual plasma is proposed and designed to diagnose the density of residual plasma during sheath expansion. The experimental platform is built on the basis of the synthetic circuit and detachable vacuum chamber. The diagnostic system uses Langmuir probe array to diagnose the post-arc plasma density change in vacuum interrupter, which reflects the dynamic process of sheath expansion in the gap. The effect of different current sizes and contact spacing on residual plasma is discussed in this paper. The plasma densities diagnosed by different position probes are used to analyze the post-arc characteristics of vacuum circuit breakers from a micro-level. The accuracy and reliability of the diagnostic system are verified by comparing with the previous studies, which provides some reference value for the future research on the post-arc micro-characteristics of vacuum breaker.