Analysis of anode thermal process of high-current vacuum arc

Abstract

The anode is heated continuously by the inter-electrode plasma flowing towards the anode and cooled by evaporation and radiation during the arc interruption process of vacuum circuit breakers (VCBs). The anode thermal process determines whether the VCBs can interrupt the fault current successfully. In this study, we established a two-dimension anode thermal model taking into account the molten and phase change of local regions within anode, the Joule heating, the thermal conduction and the heat radiation. The heat flux density boundary condition on the anode surface utilized that obtained by solving of MHD equations of vacuum arc. Calculation of the temperature distribution and the molted pool size of anode were then conducted. After that, the analysis of the influence of arc current on the maximum temperature of anode during the current interruption was carried out in detail. The research work can serve as a base for the study of the post-arc dynamic dielectric recovery of VCBs.