直流电弧运动过程中重击穿现象及机理研究

研究了桥式双断点触头在不同电压下分断直流阻性回路电弧运动过程中重击穿的特性参数。采用高速摄像机拍摄了电弧及重击穿图像。利用光谱仪测量了电弧运动过程中弧柱所经过区域的平均温度。研究了电压与重击穿发生的关系。基于一组漂移扩散方程耦合电场泊松方程,建立了小间隙(2 mm)中考虑电弧运动期间弧柱所经过区域残留金属蒸气的直流(电压等级200~500 V)重击穿放电形成过程的微观数学模型。通过仿真结果得到了重击穿的形成过程及微观参数,同时分析了弧柱所经过区域的初始温度和电压对重击穿放电形成过程的影响。很好地解释了重击穿形成过程中鞘层、弧前预击穿导电通道的形成机理。

Research on Restriking Phenomena and Mechanism During DC Arc Motion Process

The restriking characteristics during the DC arcing period have been studied with a pair of bridge-type double-break contacts which is used to break a DC resistive circuit at different voltages. The high-speed cameras are used to obtain the restriking arc images. The spectrograph is used to measure the average temperature of the region through which the arc column passed during the arc motion process. Then the relationship between the voltage and the occurrence probability of restriking is set up. The microscopic mathematical model of the restriking discharge is established based on a set of drift-diffusion equations coupled with the Poisson equation. In the model,the contact gap is 2 mm,the DC voltage is from 200 V to 500 V,and the residual metal vapor between the contacts during the restriking process is considered. The restriking formation process and the microscopic parameters are obtained by the simulation results. The initial temperature of the region through which the arc column passed and the voltage during the formation process of the restriking are analyzed at the same time. In this way,the sheath and the formation mechanism of pre-breakdown channel during the restriking arc ignition process can be explained clearly.