雷电冲击电压下串联空气球隙击穿特性

Breakdown Characteristics of Series Connected Ball Air Gaps Under Lightening Impulse Voltage

为研究雷电冲击电压下串联空气间隙的击穿特性,文中以球-球间隙为研究对象,通过对悬浮电极电位的直接测量,实验研究了两间隙大小之和不变的情况下,两间隙大小分布不均匀程度对串联空气间隙击穿电压和击穿延时的影响。研究表明,不均匀程度较大时,较低电压下存在单个间隙放电、总体不击穿的现象,较高电压下两间隙将出现非同期击穿;不均匀程度较小时,两间隙同期击穿。随串联间隙不均匀程度降低,击穿电压先下降后上升,击穿延时减小至零并维持。击穿电压极小值对应于使击穿延时降至零的间距。在此基础上,提出了不均匀系数的概念,发现随不均匀系数增加,同期击穿情况下击穿电压近似线性下降,非同期击穿情况下击穿电压近似线性上升。据此推测,同期击穿情况下击穿电压由较小间隙决定,非同期击穿情况下击穿电压由较大间隙决定。

In order to study the breakdown characteristics of series-connected air gaps,ball-ball air gaps were taken as research targets to experimentally study a dependence of breakdown voltage and delay time on gap distance distribution when the total gap distance remains unchanged.Results show that when the gap distance distribution is relatively uneven,single-gap-breakdown occurs at lower voltages,and asynchronous breakdown occurs at higher voltages.When the gap distance distribution is relatively even,synchronous breakdown occurs.With the decreasing of the unevenness,the breakdown voltage first decreases and then rises,the breakdown delay time decreases to zero and maintains.The minimum value of the breakdown voltage corresponds to the gap distance that reduces the breakdown delay time to zero.Based on the results,the unevenness factor is proposed to describe how uneven the gap distance distribution is.It is found that the breakdown voltage decreases almost linearly under the synchronous breakdowns,increases almost linearly under the asynchronous breakdowns.It is thus proposed that the breakdown voltage is decided by the smaller gap for synchronous breakdowns,and by the larger gap for asynchronous breakdowns.