Two-Dimensional Particle-in-Cell/Monte Carlo Collisional Simulation of the Post-Arc Breakdown in Vacuum Circuit Breakers

Vacuum circuit breakers are widely used in medium-voltage power systems, and the post-arc breakdown is a key factor limiting performance of the vacuum circuit breakers. In this work, a 2-D particle-in-cell/Monte Carlo collisional model is developed to investigate the post-arc breakdown. The residual plasma, metal vapor, inhomogeneous temperature distribution and electron emission on the post-arc cathode surface and various collisions between charged particles, and metal vapor are taken into consideration in the model. Simulation results show that the post-arc breakdown initiates in the vicinity of the post-arc cathode center. At the moment when the post-arc breakdown occurs, a potential hump forms near the post-arc cathode center, and the plasma density increases by two orders, which are consistent with the published result obtained by 1-D hybrid simulation model. Simulation results on the effect of metal vapor density show that the post-arc breakdown occurs earlier with increasing metal vapor density, and the post-arc breakdown cannot occur when the metal vapor density is below 1020 m−3.