计及新型泄漏电流指数的玻璃绝缘子风险评估方法

A Risk Assessment Method for Glass Insulators with a New Leakage Current Index

针对高压(HV)玻璃绝缘子均匀与非均匀污染检测难度大、风险评估不准确等问题,提出了一种基于新型泄漏电流指标Rhi的高压玻璃绝缘子风险评估方法。该新型泄漏电流指标Rhi由泄漏电流的第3次、第5次和第7次谐波推导出来,并根据测量到的临界电压梯度(Ec),采用两串33 kV的帽针式玻璃绝缘子,在不同的上下表面比(J)和润湿率下对受污染绝缘子进行临界电压应力试验,以评估其风险水平。此外,还分析了等效盐沉积密度(ESDD)与不可溶沉积密度(NSDD)之比对绝缘子闪络发生的影响。最后,通过实验验证了该新型指标能更准确地预测绝缘子的危险程度和闪络发生的概率。

In view of the difficulty in detecting the uniform and non-uniform contamination of high voltage(HV)glass insulators and the inaccuracy of risk assessment,a risk assessment method for HV glass insulators based on a new leakage current indicator Rhiwas proposed. The new leakage current index Rhiwas derived by the leakage current of the 3rd,5th and 7th harmonics,according to the measured critical voltage gradient(Ec),using two bunch of 33 kV cap glass pin type insulator,the critical voltage stress test of polluted insulator in different top and bottom surface ratio(J)and wetting rate was carried out to evaluated the level of risk. In addition,the influence of the ratio of the equivalent soluble deposit density(ESDD)to that of non soluble deposite dentisty(NSDD)on insulator flashover was also analyzed. Finally,the experimental results show that the new index can predict the risk degree of insulator and the probability of flashover more accurately.