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Simulation on dynamic arc-before process of large current vacuum breaking

Arc breaking at the function of large current is one of the bottlenecks for the development of vacuum breaker to higher voltage level and it is also the hotspot nowadays. Seen from the reasons of arc igniting and its influencing factors, arc-before process from the contacts separating to stable arc igniting is the base of arc research. Arc-before process model of vacuum circuit breaker is developed here based on gas dynamic equation. Its breaking current is 20kA and clearance is 10mm. Collisions between charged particles and metal vapor and electrodes are considered in the simulation. The physical nature of the sheath and arc column's formation, the space charge densities and their effects on electric field strength before the steady state of arc plasma are simulated here. The simulations in this paper lay the foundations for depth understanding of vacuum arc plasma's formation mechanism and it also improves people's knowledge of arc igniting process which will benefit for exploring effective method to control and quench arc.