变电站支柱绝缘子的覆雪闪络特性  

Flashover Characteristics of Snow-covered Post Insulators in Substations

作　　者：张若兵[1] 李剑超 王黎明[1] 张楚岩[1] 卢明[2] 刘泽辉[2] 

机构地区：[1]清华大学深圳研究生院,深圳518055 [2]国网河南省电力公司电力科学研究院,郑州450052

出　　处：《高电压技术》2016年第12期3823-3829,共7页High Voltage Engineering

基　　金：国家电网公司重大科技项目(521700140004);河南省电力公司科技专项(C317021350JC)~~

摘　　要：降雪天气中绝缘子上的覆雪层在融雪过程湿润污层,造成其绝缘性能下降。为研究不同伞形支柱瓷绝缘子覆雪条件下的绝缘性能,首先开展覆雪支柱绝缘子的模型建立与电场仿真,随后开展了人工覆雪条件下不同伞形支柱绝缘子闪络试验。试品包含3种不同伞形结构的支柱绝缘子。试验结果表明:未融雪时的覆雪绝缘子绝缘性能下降不显著,在覆雪大部分融化、融化雪水在绝缘子伞裙表面溶解污秽形成水膜并沿伞裙边缘滴下时为绝缘性能下降最严重时刻;溶解了污秽的高电导率水膜是闪络电压降低的重要影响因素;雪闪电压与融雪时间呈现U形曲线关系,U形曲线的最低点可以表征该型支柱绝缘子在该污秽水平下的耐雪闪能力;支柱绝缘子的伞形结构也对其雪闪特性有影响。A large amount of snow accumulates on insulators which melts to humidify the filth layers, directly leading to the decline of the insulation capability. To study the insulation performance of post porcelain insulator covered with snow, we first established a model and simulated the electric field of snow-covered post insulators, then tested the flashover characteristics of different kinds of the insulators in condition of artificial snow-covering. The sample contains three post insulators of different sited geometry. It is shown that a heavily covered sample performs well in maintenance of the insu- lation capability. But when there comes the large-scale melting of the snow, the insulation performance turns severe because the melting snow forms the water film and some even drops from the edge. Such water film containing with sol- uble salts is of high conductivity and turns out to be the essential factor of the flashover voltage＇s decrease. The snow flashover voltage and the snow melting time appears to be a U-shaped relationship, of which the trough point can be used to characterize the insulation capability of the post insulator on certain contamination level. Also, the shed geometry has an effect on the snow flashover characteristics of the post insulators.

关 键 词：支柱绝缘子 覆雪闪络 融雪时间 电场仿真 人工污秽试验 人工覆雪 伞形结构 

分 类 号：TM216[一般工业技术—材料科学与工程] TM63[电气工程—电工理论与新技术]