Simulation Analysis of Post-arc Sheath Development Process of VCB in QPS

Vacuum Circuit Breaker (VCB) with oscillation zero-crossing circuit is used to interrupt high current, whether the VCB can successfully interrupt the current depends on the competition between the post-arc dielectric recovery process and the fracture recovery voltage. The recovery voltage depends largely on the peripheral circuit of the vacuum interrupter, so the study of the post-arc dielectric recovery process plays a decisive role in the breaking capacity of the VCB. Based on the theoretical analysis of the continuous transition model and the post-arc dielectric recovery process, combined with the peripheral circuit of VCB, a numerical simulation calculation model is established for the sheath development stage during the post-arc dielectric recovery process. The simulation results show that in the sheath development stage, the sheath thickness changes exponentially, and the post-arc dielectric recovery ability can be improved by selecting the topological parameters of the commutation circuit and regulating the arc. The research in this paper provides a strong support for better understanding of vacuum arc and guiding the design of VCB.