Failure Characterization of Silicone Rubber in Corrosive Environments Based on Leakage Current Characteristics

Abstract

Due to the growing usage of composite insulators in transmission and distribution networks, the development of composite insulators has reached the stage of systematic reliability study. This paper discusses the failure properties of HTV silicone rubber in different energized corrosive environments and explores the characteristics that can characterize insulation failure. The findings demonstrate that the leakage current characteristics (the maximum values, the number of characteristic pulses, and cumulative charge) can effectively characterize the surface state of silicone rubber in corrosive environments. The flashover tests during the withstand voltage experiment accelerated the electrical performance degradation of silicone rubber and increased the leakage current. The three leakage current characteristics increase with experimental time, applied voltage, and fog conductivity. The occurrence of flashover is related to the fluctuation range of leakage current. The three leakage current characteristics in the alkali fog with the same conductivity and applied voltage are significantly higher than those in salt and acid fog. A failure characterization method of silicone rubber based on the proportion of pulse number and cumulative discharge is proposed in this paper. The findings are helpful in forecasting pollution flashovers and insulation failure in heavy fog, coastal, and industrial pollution areas.