In this article, a new method is proposed to identify the health condition of composite insulators through investigating the leakage current (LC) along with the electric potential (EP) and electric field stress (EFS) profiles. In this regard, variations of the LC harmonics and the distribution profiles of the EP and EFS are investigated through a series of experimental and simulation analyses conducted on composite insulators under various environmental and pollution conditions. Fast Fourier transform (FFT) and a COMSOL-multiphysics environment are utilized to analyze this variation. The results reveal a strong correlation between the LC harmonics and the insulator health condition. A new diagnostic criticality index based on the third to the fifth harmonic ratios of the insulator LC is proposed to quantify the composite insulator criticality and predict the likelihood of flashover occurrence. The EP and EFS analyses can be used to provide a complementary diagnosis of the insulator's health state under severe pollution and humidity conditions. The proposed analysis enables the transmission line network operator to get an insight into the insulators' functional status, thus improving the network reliability through avoiding insulator failure and adopting a proper condition-based maintenance scheme.

中文翻译：

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基于新漏电流诊断指标的复合绝缘子临界识别


本文提出了一种通过研究漏电流 (LC) 以及电势 (EP) 和电场应力 (EFS) 曲线来识别复合绝缘子健康状况的新方法。在这方面，通过对复合绝缘子在各种环境和污染条件下进行的一系列实验和模拟分析，研究了LC谐波以及EP和EFS分布曲线的变化。利用快速傅里叶变换 (FFT) 和 COMSOL 多物理场环境来分析这种变化。结果表明，LC 谐波与绝缘子健康状况之间存在很强的相关性。提出了一种基于绝缘子 LC 三次谐波至五次谐波比的新诊断关键性指数，用于量化复合绝缘子关键性并预测闪络发生的可能性。 EP和EFS分析可用于对严重污染和潮湿条件下绝缘子的健康状态提供补充诊断。所提出的分析使输电线路网络运营商能够深入了解绝缘子的功能状态，从而通过避免绝缘子故障并采用适当的基于状态的维护方案来提高网络可靠性。