沙尘环境下棒-板间隙交流放电特性研究

近年来沙尘对电力系统外绝缘的影响已不容忽视,但国内外的相关研究尚不多,为研究沙尘环境下的放电特性,选择尖-板间隙为研究对象,搭建沙尘模拟实验平台,开展交流放电特性试验研究,得出间隙距离和沙尘体积分数等因素对尖-板间隙交流放电的影响规律:当沙尘体积分数较小时,尖-板间隙的交流击穿电压随着沙尘体积分数的增大而下降;当沙尘体积分数较大时,尖-板间隙的交流击穿电压随着沙尘体积分数的增大而增大。可认为存在某一沙尘体积分数(1%左右),使得交流间隙击穿电压最小,且该体积分数与间隙距离无关。在此基础上,在有限元仿真软件FlexPDE中搭建了尖-板电极间隙的仿真模型,分析了沙尘环境下尖-板间隙的击穿机制。

AC Discharge Characteristics of Rod Plate Gaps in Sand Dust Environment

In recent years, the influence of sand and dust on the external insulation of power system can not be ignored, but there are few studies about that at present. In order to study the discharge characteristics in dust environment, the tip-to-plate gap is employed. A sand-dust simulation experiment platform is built to carry out the AC discharge characteristics test. The effects of gap distance and dust duty ratio on AC discharge in tip-to-plate gap are obtained. The results show that when dust duty ratio is small, AC breakdown voltage in tip-to-plate gap decreases with the increase of dust duty ratio. While AC breakdown voltage in tip-to-plate gap increases with the increase of dust duty ratio when dust duty ratio is large. Therefore, it can be considered that there exists a certain duty cycle of sand and dust (about 1%), which minimizes the breakdown voltage of AC gap. It is found that the duty cycle is independent on the gap distance. Furthermore, the simulation model of tip-to-plate electrode gap is built in the finite element simulation software FlexPDE, and the flashover mechanism of tip-to-plate gap in dust environment is analyzed.