The flashover probability of vacuum insulator stack (VIS) is calculated based on statistical model. The calculation results show that the probability reduces with lower peak voltage of VIS, shorter effective pulse duration, smaller material constant and smaller stack radius in a certain range of VIS voltage. The flashover probability is also calculated with the consideration of magnetic flashover inhibition (MFD under different critical ratios. The critical ratio is defined as the ratio of electric field strength to magnetic induction strength when MFI begins to be effective, and is changed according to different angles between insulator and electrode considering the relation of the three-phase point electric field strength of cathode and the average electric field strength of VIS. The simulation results indicate that the flashover probability is reduced by the effect of MFI.%基于统计学闪络经验公式,计算绝缘堆闪络概率,结果显示:绝缘堆电压峰值越低、电压有效作用时间越短、材料常数越小,则闪络概率越低；在一定绝缘堆电压范围内,绝缘堆半径越小,闪络概率越低.考虑磁场闪络抑制效应,计算了绝缘堆闪络概率.通过电场强度与磁感应强度之比得到磁场开始闪络抑制作用的临界比值.根据绝缘体与电极的夹角以及阴极三相点电场强度与平均电场强度的关系,得到不同的临界比值,比较闪络概率计算结果的差异.计算结果表明:在磁场闪络抑制效应作用下,绝缘堆闪络概率下降.
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