污秽悬式绝缘子的交流污闪计算模型

AC Flashover Calculation Model of Polluted Suspension Insulator

为了更好地研究不同附盐密度绝缘子的污闪过程及预测其污闪电压,选取了普通型LXY-160、钟罩型FC-16P和空气动力型FC-160D为研究对象,求取其按爬电距离展开的平板模型,即绝缘子的泄漏距离对应于平板模型的长,沿绝缘子泄漏距离各点处的圆周长对应平板模型的宽。忽略局部电弧的一些随机性状态,统一认为:导致污闪的局部电弧都是从平板模型两端同时起弧并逐渐相向发展,发展到临界长度时两端同时存在电弧。以此为基础,引入飘弧系数K,推导了剩余污层电阻表达式和双电弧污闪计算模型的临界条件,并编程求解了3个平板模型上、下表面临界电弧长度和临界闪络电压。还制作了3种绝缘子的平板模型进行人工污秽试验,获其50%污闪电压。比较计算结果和试验结果,可见双电弧污闪计算模型能较好地对污闪电压值作出定量估算。轻污时飘弧现象不严重,试验电压点一般介于K=1和K=1.2两条曲线之间;重污时飘弧现象比较严重,试验点主要集中在K=1.2和K=1.5两条曲线之间。

In order to research flashover process of insulator with different SDD and to predict its flashover voltage,three types insulators,LXY-160、FC-16P and FC-160D were researched and expanded to flat plate models, in which length is corresponding to insulator＇s leakage distance and width corresponding to circumference.Neglecting some stochastic states of partial arc,two arcs,which lead to flashover,burn at cap and pin at the same time.While in critical state,these two arc still exist.Based on this phenomenon,arc fluttering factor was introduced,so that the expression of resistance of remaining pollution layer and the critical condition of double arc pollution flashover model were derived.At the same time,the critical length of arc and flashover voltage were calculated via Matlab.Three flat plate models were established to test artificial pollution.Comparing flashover voltages got by calculating and testing,we find that the calculation model can estimate flashover voltage quantitatively.While light pollution,arc-fluttering phenomenon is not serious and voltage got by testing is between curve K=1 and K=1.2.While heavy pollution,arc-fluttering phenomenon become serious and voltage got by testing is between curve K=1.2 and K=1.5.