一起500kV悬式瓷绝缘子零值率高的原因分析

Analysis on High Zero Rate of a 500 kV Suspended Porcelain Insulator

依据有关标准和规程要求,测量出绝缘子真实的绝缘电阻值是判断绝缘子劣化的数据支撑。以一起500kV悬式瓷绝缘子的绝缘电阻检测出三分之一的零值率为例,对悬式瓷绝缘子进行机电破坏负荷试验、干工频耐受电压试验、绝缘电阻测试,试验室检测结果表明,现场检测出现零值率高的原因是悬式瓷绝缘子受湿度影响,导致使用SJC-8型绝缘子零值检测仪的测量结果出现误差。根据研究结果建议,在以后的绝缘子绝缘电阻检测过程中,禁止在雨后和湿度较大的情况下进行;同时检测过程中应结合红外精确测温检测结果和悬式瓷绝缘子绝缘电阻检测结果共同判定悬式瓷绝缘子是否劣化。研究结论对现场的悬式瓷绝缘子零值测量工作具有较强指导意义。

According to the requirements of relevant standards and regulations,measuring the real insulation resistance value of the insulator is the data support for judging the deterioration of the insulator.Taking as an example a 500 kV suspended porcelain insulator one-third of whose insulation resistance value detected is zero rate,the paper carries out electromechanical damage load test,dry power frequency withstand voltage test and insulation resistance test on suspended porcelain insulators.The laboratory test results show that the reason for the high zero value rate in the field test is that the suspended porcelain insulator is affected by humidity,which leads to the error in the measure results of SJC-8 type insulator zero value detector.According to the research results,it is suggested that the insulation resistance testing process of insulators should be prohibited after rain and in the case of high humidity.At the same time,it is necessary to combine the results of infrared accurate temperature measure and insulation resistance detection of suspended porcelain insulator to jointly determine whether the suspended porcelain insulator is being deteriorated.The research conclusion has a strong guiding significance for the zerovalue measurement of suspended porcelain insulator in the field.