Influence of different factors on gap breakdown process with hot electrode and high temperature gas medium in low voltage circuit breaker chamber based on particle-in-cell/Monte-Carlo collision simulation

Different factors such as gas composition inside the low voltage circuit breaker (LVCB) chamber and the residual plasma in the post-arc stage affect the breakdown process, which in turn affects the breaking capacity of LVCBs. In this paper, the effects of non-parallel electrode structure, gas temperature and pressure, electrode temperature, and gap distance on gap breakdown of hot electrode under high temperature gas conditions were studied, for which a particle-in-cell/Monte-Carlo collision simulation model has been established, which takes into account the effects of high-temperature gas components, cathode electron thermal emission, electron collision ionization and other effects, and simulation studies have been conducted. The simulation results show that the increase in gap gas temperature, the decrease in air pressure, and the increase in electrode temperature will lead to the gap breakdown more easily. With the increase in the gap length, the breakdown voltage increases, but the average electric field intensity required for breakdown decreases. In the non-parallel electrode structure, the breakdown occurs first at the position with the shortest gap distance, then the cathode sheath forms and extends along the electrode surface to other areas, and finally, the entire gap breaks down.