Particle-in-cell simulation of rebreakdown in post-arc stage for low voltage circuit breaker

Low-voltage circuit breakers are widely used in power distribution systems. Sometimes the gap between electrodes may breakdown again after the arc is extinguished. In this paper, a 1D3V particle-in-cell/Monte Carlo collisional (PIC/MCC) model is developed to study the re-breakdown in the post-arc hot air gap of low-voltage circuit breakers. The model takes into account the cathode electron thermal emission, secondary electrons, elastic and inelastic collisions between particles and background gas. From the simulation results, the electrons in the early stage of simulation mainly come from the background initial plasma and cathode thermal emission. With the increase of the gap voltage, the density of electrons and ions rises, which leads to the gap re-breakdown. A plasma sheath forms near the cathode, and the electric field in it is obviously distorted. In addition, the influence of different parameters such as electrode temperature, gas pressure, gas temperature, gas composition is studied. With the increase of gas temperature, the breakdown voltage decreases significantly. The increase in cathode temperature and the decrease in gas pressure cause the gap easier to breakdown. When copper vapour is mixed into the gas, the gap is more difficult to breakdown under the same gas temperature and electrode temperature.