Study of the dissipation of residual plasma with a one-dimensional particle-in-cell model in a vacuum circuit breaker

Abstract

Vacuum circuit breakers have been being widely used in the electric power system in recent years for its excellent breaking capability. The whole interrupting process can be divided into two main stages: the arcing phase and the post-arc dielectric recovery phase. The later phase has a decisive effect on the whole interruption which has attracted many concerns. The dissipation of the residual plasma emitted from the cathode spots under the transient recovery voltage is the first stage of the post-arc dielectric recovery phase. At the moment of current zero, the ions are accelerated into the post-arc cathode, whereas the electrons reverse to the post-arc anode when the fast increasing transient recovery voltage imposes on the post-arc cathode. As a result, an ion sheath forms in front of post-arc cathode and develops to the post-arc anode. The post-arc current forms during the sheath expanding process. The continuous transition model and the hybrid Maxwell-Boltzmann model have been applied to the study of the dissipation of the residual plasma. A more self-consistent full particle-in-cell model, which treats both ions and electrons as macro particles, has been developed for the study of the influence of plasma temperature in previous work1. In this paper, a particle-in-cell model is adopted for the simulation. The measurement results of post-arc current and the transient recovery voltage are taken from the reference 2 The residual plasma temperature is estimated with the theory of ion rarefaction wave. The residual plasma density is estimated by the integration of post-arc current from measurement with some modification. From the simulation we can obtain a post-arc current waveform which is closer to that from the measurement.