Study on the transport characteristics of DC vacuum arc plasma under actual magnetic field conditions

Mechanical DC circuit breakers based on forced over-zero technology need to superimpose reverse high-frequency currents to generate artificial over-zero points when achieving DC interruption, which can cause serious eddy current phenomena in the contacts and severe magnetic field hysteresis in the arc area, resulting in ineffective interrupting of the vacuum arc at the moment of current over-zero. In this paper, we establish a three-dimensional transient simulation model of DC interrupting vacuum arc under actual magnetic field conditions for the vacuum arc generated in the DC interrupting process, and study the plasma transport characteristics of DC vacuum arc under actual magnetic field conditions. Simulation results show that the arc magnetic field will have an important impact on the distribution of the parameters of the DC vacuum arc plasma, and the higher current drop frequency of DC interruption will lead to a strong remanence between the poles at the moment of current crossing zero, which will lead to the arc plasma can not effectively spread and is not conducive to arc interruption. The research results can deepen the understanding of the internal physical processes of the DC vacuum arc and provide a theoretical basis for the regulation and control measures of the DC interrupting vacuum arc.