沿面闪络触发真空开关初始等离子体特性实验

An Experimental Study on Initial Plasma Characteristics of Surface Flashover Triggered Vacuum Switch

提出了一种RC阻容式电荷收集器,并对触发真空开关触发初始等离子体特征进行了实验研究。实验结果表明,在触发真空开关初始等离子体的起始阶段有一个尖峰脉冲,而且初始等离子体电流波形呈振荡衰减的过程。初始等离子体电流波形的第一个振荡峰的极性取决于触发脉冲的极性。触发初始等离子体的电子电荷略大于离子电荷;触发初始等离子体的电荷随触发电压、触发电流、触发电荷的增加呈线性增加;触发初始等离子体在TVS真空间隙中的扩散时间受触发电压、触发电流、触发电荷以及TVS真空间隙距离的影响,在触发电压小于8kV时,初始等离子体的扩散时间随触发电压的增加呈线性减小,而后基本稳定在66～69ns;初始等离子体的扩散时间随TVS真空间隙距离的增加而增加,当真空间隙距离从0.5mm增加至8mm,初始等离子体的扩散时间从50ns增大至70ns。

In this paper, a RC charge collector is proposed and the initial plasma characteristics of TVS are experimentally analyzed. The experimental results indicate that a spike appears on the waveform of initial plasma current after triggering voltage appalling, and the waveform of initial plasma current oscillating decreases to zero after the trigger voltage breaking, and the charge of initial plasma includes electronic and ionic charge and the electronic charge is slightly more than ionic charge. The charge of initial plasma is affected by trigger voltage, trigger current, and trigger charge. From experiments, it is shown that the charge of initial plasma increases with the increment of triggel： voltage, trigger current and trigger charge, but the ratio of charge of initial plasma to trigger charge decreases with increasing in trigger voltage and the ratio with negative trigger is slight larger than the ratio with positive trigger. After the initial plasma being ejected to the vacuum gap of triggered vacuum switch, they expand in the Vacuum gap. The expansion time, during the initial plasma leave the trigger to arrive at anode of triggered vacuum switch, decreases with the increment of trigger voltage below 8kV, and then the expansion time remains stable during 66-69ns with the trigger voltage keeping on growing. And also the expansion time increases from 50ns to 70ns with expanding of the vacuum gap distance of triggered vacuum switch from 0.5mm to 8mm.