Dynamic model simulation of arc formation in vacuum circuit breaker

Based on the theories of fractal and gas discharge, microscopic morphology of vacuum arc, the process of arc formation and development of discharge channel in the vacuum circuit breaker are simulated. The effects of temperature and electromagnetic field on the arc are also considered. The opening stroke is 10 mm in our work. Voltage is 75 kV, and current is 1 kA. The effects of temperature on the arc radius, the role of self-generated magnetic fields and thermal conduction are simulated here. The results show that electron density and the coefficient of heat conduction are increased gradually. Average temperature increases at first and decreases latter, then collision coefficient enhances. The radius of arc also increases in the stage of arc formation and development. The arc radius contract and stable arc forms after breakdown.