Experimental test and simulation analysis on surface flashover characteristics of embedded electrode into machinable ceramic in vacuum

Surface flashover phenomena in vacuum restrict the overall performance of vacuum solid insulation system. Since accidents caused by surface flashover in vacuum occur constantly, it is always the international highlight to study some new insulating materials and insulation structure with high electric withstanding for vacuum insulation. On the basis of the novel low melting temperature machinable glass ceramics for vacuum insulation system, which has excellent machinable performance and good electrical properties, the samples of embedded electrode into machinable ceramics are machined, and then the samples' flashover voltage of different embedded mode and embedded depth are investigated under nanosecond pulse voltage in vacuum. The electric field distributions and electric field of cathode triple junction (CTJ) are simulated to explain the experimental results. The experimental results indicate embedded electrode in cathode can increase the surface flashover voltage of the sample; with increasing of the embedded depth, the surface flashover voltage tends to be increased. The simulation results indicate embedded electrode in cathode can decrease the electric field of CTJ, and with increasing of the embedded depth, the electric field of CTJ tends to be decreased.