高真空条件下气压变化对绝缘闪络特性的影响

对纳秒脉冲(10/30ns)下真空绝缘闪络电压随气压的变化趋势进行了实验研究,探讨的气压范围介于8×10-4Pa至标准大气压之间。研究发现,当气压位于高真空区域(10-4～10-1Pa)时,随着气压的改变,绝缘闪络电压无明显变化,基本保持恒定。深入剖析真空环境下的气体解吸附过程,得出如下结论:当气压进入高真空阶段时,表面放气已成为主要气体负荷,所释放气体均源于绝缘体表面的解吸附气体。真空闪络现象,事实上是一种在绝缘体表面气体解吸附后所形成一高气密环境中发生的放电过程。

Dependence of Flashover Voltage on the Change of Gas Pressure under High Vacuum

Dependence of flashover voltage on gas pressure has been measured in vacuum and in atmospheric air using 10/30-nanosecond pulse power. The scope of gas pressure is between 8×10-4 Pa and standard atmospheric pressure. The laboratorial data show that the voltages are independent of the gas pressure under high vacuum(10-4～10-1 Pa). As viewing from sorption and desorption, a conclusion has been made, that desorption begins early before the flashover and outgassing is the most important gas resource when gas pressure is in the range of high vacuum. Flashover is in fact a type of gaseous discharge process in a high-pressure phenomenon immediately above the insulator surface.