含悬浮导体的棒板间隙工频击穿特性

AC Breakdown Characteristics of Rod-plane Gap with Floating Conductor

为揭示工频电压作用下空气间隙介入悬浮导体后的击穿放电特性,论文开展了80 cm棒–板间隙布置不同形式悬浮导体后的击穿放电试验。试验研究了悬浮导体直径及布置位置对间隙击穿电压的影响,并基于高速摄影仪及平面镜搭建的间隙放电观测系统研究了放电过程及其路径特征。研究结果表明:直径与长度之比大于0.6的大直径悬浮导体布置于间隙中部时可抬升间隙击穿电压,同时放电路径出现"绕过"悬浮导体击穿现象。综合放电过程图像及电场仿真结果对绕过发生原因进行了初步解释,指出大直径悬浮导体周围电场弱、表面自由电荷的积累,以及对光电离的阻碍作用是绕过现象发生的重要原因。

To investigate the influence of a floating conductor on the breakdown characteristics of air gap, tests of 80 cm rod-plane gap discharge with conductors of different arrangements were conducted. The influences of the diameter and position of floating conductor on the breakdown voltage were studied. Meanwhile, the discharge process was recorded by using a high-speed camera and a mirror. The results show that a large diameter conductor with diameter-to-length ratio greater than 0.6 arranged in the middle of the gap can raise the breakdown voltage and lead to bypassing phenomenon. The possible reasons for "bypassing" discharge were discussed using recorded images and electric field simulation. It is pointed out that the weak electric field around the large diameter floating conductor, free charge accumulation and the hindrance to photo ionization are the important reasons for the bypassing phenomenon.