固体绝缘周围的气体或液体电介质被击穿时 , 沿固体绝缘表面放电的现象 , 称为闪络。
When gas or liquid dielectrics around solid insulation are broken down, the phenomenon of discharge along the surface of solid insulation is called flashover.
在脏污地区的瓷质绝缘子表面落有很多工业污秽颗粒 , 这些污秽颗粒遇潮湿会在瓷表面形成导电液膜 , 使瓷质绝缘的耐压显著下降 , 闪络电压变得很低 , 这是瓷质绝缘在污湿条件下极易闪络的原因。污和潮是污闪的必要条件 , 瓷绝缘只脏不湿不会引起闪络。
There are many industrial contaminated particles on the surface of ceramic insulators in dirty areas. When these contaminated particles are wet, they will form conductive liquid film on the surface of the porcelain, which makes the voltage withstand of the ceramic insulation decrease remarkably and the flashover voltage become very low. This is the reason why the ceramic insulation is easy to flashover under dirty and wet conditions. Pollution and moisture are necessary conditions for pollution flashover. Ceramic insulation is only dirty and not wet, which will not cause flashover.