Research on aging evaluation and remaining lifespan prediction of composite insulators in high temperature and humidity regions

Abstract

Composite insulators are the critical components of power transmission systems. 371 composite insulators with an operating duration between 3 and 22 years from the lines in high temperature and humidity regions were sampled. The material properties, mechanical properties, electrical properties and interface properties of these insulators were researched systematically. Moreover, 19 aging characteristic index were put forward to describe the aging conditions of insulators. We analyzed the correlation between the aging index and operating years, and corresponding aging mechanism was discussed in this paper. Meanwhile, according to the analysis results, we established lifespan prediction models based on physics and statistics respectively. The results showed: lifespan of the sampled insulators was determined by the thermal oxidation process of silicone rubber. Lifespan of the silicone rubber material was 14.6 years while the electrical lifespan of composite insulator was 18.9 years. With regard to the rest of the insulators in high-temperature and high-humidity regions, their remaining lifespan could be predicted in accordance with the mechanical load and Fourier translation infrared spectroscopy (FTIR) test results. In the end, we selected 20 insulators which had run for 14 years, and predicted their lifespan with the method mentioned in this article, the forecast error was 1 year.