雷电冲击下SF_6气体放电击穿电压分散性的实验研究  

Experimental Research of Dispersion of SF_6 Discharge Breakdown Voltage Under Lighting Impulse

作　　者：张乔根[1] 游浩洋 郭璨[1] 秦逸帆 马径坦 文韬[1] 

机构地区：[1]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《高电压技术》2016年第11期3415-3420,共6页High Voltage Engineering

基　　金：中国南方电网有限责任公司资助项目(CSGTRC[2015]K1552B02)~~

摘　　要：一般应用升降法进行冲击下SF_6气体放电击穿特性实验时,要求击穿电压的分散性小于3%,以保证测得数据的可靠性。但是在实验过程中发现,SF_6气体相对于其他气体而言,击穿电压的分散性普遍偏大,一些情况下甚至超过了5%,而国内外针对SF_6气体放电击穿电压的分散性仍缺乏系统的研究。为此,在正、负标准雷电冲击(LI)作用下,实验研究了SF_6气体放电击穿电压的分散性随电极尺寸、气压和间隙距离的变化规律。结果表明:当间隙距离d=33 mm,电极曲率半径r=40、15、8 mm时击穿电压的分散性随气压增长而均呈现减小趋势;正LI下击穿电压的分散性随电场不均匀系数的增大而呈现先下降后上升的"U"曲线趋势,负LI下击穿电压的分散性随电场不均匀系数的增大而呈现先上升后下降的倒"U"曲线趋势;当电极曲率半径r=8 mm,间隙距离d=7、15、33 mm时击穿电压的分散性随着气压的增长而均呈现下降趋势。由此可得结论:正、负LI下SF_6气体放电击穿电压的分散性随着间隙距离的增加而均呈现线性增大的趋势。Generally, when the up-and-down method is used to research the discharge characteristics of SF6 under impulse voltage, dispersion of breakdown voltage is required to be less than 3%, which guarantees the reliability of data. But during the process of experiment, the dispersion of breakdown voltage of SF6, comparing with other gas, is usually significant and even larger than 5%. Therefor, we discuss the changing law of SF6 breakdown voltage dispersion with electrode size, gas pressure and gap length under positive and negative standard lighting impulse（LI）. The results show that when gap length d=-33 mm and radius of electrode r=40, 15, 8 mm, the voltage dispersion is lower as the pressure grows. The change trend of voltage dispersion, as the field nonuniformity factor grows under positive impulse, is alike ＂U＂ curve trend, which is growing at first and then declining. And the change trend of voltage dispersion is alike inverse ＂U＂ curve trend under negative pulse, which is declining at first and then declining; when the radius of the electrode r=8 mm and the gap length d=-7, 15, 33 mm, the voltage dispersion declines as the pressure grows. The coefficient of dispersion grows linearly with gap length under both positive and negative LI.

关 键 词：升降法 标准雷电 分散性 分散系数 电极尺寸 间隙距离 

分 类 号：TM855[电气工程—高电压与绝缘技术]