Aging Process Evaluation Method of Silicone Rubber in Composite Insulators in Natural Environmental Experiment Station

In this paper, silicone rubber on composite insulators from three different manufacturers with an operating duration between 1 and 10 years were sampled. In order to investigate the law of diminishing performance of these samples in aging process, widely adopted aging process evaluation test methods such as Hydrophobicity test, Water absorption test were performed. Based on test results, parameters significantly correlated with operating time were obtained by means of correlation calculation. Finally, considering the differences of parameter values among three manufacturers, the relative decrease value (denoted as <inline-formula> <tex-math notation="LaTeX">$w$ </tex-math></inline-formula>) of parameters was proposed as a unified standard and the equivalent equations between <inline-formula> <tex-math notation="LaTeX">$w$ </tex-math></inline-formula> and operating time were established for predicting lifespan of composite insulators in high altitude area. Test results indicate that parameters including saturated water absorption ratio <inline-formula> <tex-math notation="LaTeX">$\delta _{s}$ </tex-math></inline-formula>, the relative content of Si and O elements (<inline-formula> <tex-math notation="LaTeX">$X_{Si}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$X_{O}$ </tex-math></inline-formula>) are significantly correlated with operating time, and these three parameters can be used to characterize aging degree of composite insulators. Besides, for the relative error <inline-formula> <tex-math notation="LaTeX">$\sigma _{1}$ </tex-math></inline-formula> between theoretical operating time calculated by the equivalent relationship obtained in this paper and actual operating time is less than 20%, within the allowable error range of engineering practice, this equation can be applied to predict the operating time of composite insulators from three manufacturers in future research.