Aging characterization and lifespan prediction of silicone rubber material utilized for composite insulators in areas of atypical warmth and humidity

As a type of common and critical component, composite insulators have played an important role in power transmission systems. In order to investigate the law of diminishing function as well as to provide the macro and micro analysis of the aging process of insulators, 391 composite insulators which have run for 3–22 years in hot and humid areas were selected. The testing results showed that the mechanical properties and the electrical erosion resistance of silicone rubber had decisive effect on the functional decline. The decline process of mechanical properties was equivalently simulated with hot-oxygen aging model. The damage in the backbone of silicone rubber caused by sunlight and electric field resulted in the migration of ATH filler, which could lead to the increase in porosity of material as well as the decrease in corrosion resistance. Based on the law of diminishing mechanical function of silicone rubber and the pollution flashover tests' results, we also made prediction lifespan of both silicone rubber material as well as composite insulators.