Influence of Main Shield Voltage Distribution Configuration on the Post-arc Sheath Development of Vacuum Interrupters

In this paper, the plasma ion and electron density in the post-arc stage of vacuum circuit breakers and the influence of the main shield voltage distribution configuration on this article are simulated by a 2-D particle-in-cell model and probe diagnosis experiments. In the simulation of the distribution of charged particles and the rate of development of the sheath, there is no applied magnetic field. The main shielding voltage distribution in the post-arc stage is the main cause of the asymmetric distribution of charged particles, which also slows down the attenuation process of the plasma. The main shield voltage distribution configuration in the post-arc phase not only accelerates the media recovery of the post-arc phase of the vacuum circuit breaker, but also reduces the risk of the vacuum circuit breaker breaking down when the large fault current is disconnected in the post-arc phase. In addition, the main shield voltage distribution configuration can accelerate the ions and electrons decay and the development of the post-arc sheath layer, as well as make the post-arc potential distribution more uniform and enhance the internal insulation of the vacuum interrupter. The probe diagnosis results show that the attenuation of residual plasma is the fastest when the main shield voltage distribution configuration is 50%TRV, and the distribution of cathode spots is more uniform in arc extinguishing, which is more favorable to the diffusion of the remaining plasma.