Ageing Performance of HTV Silicone Rubber Used for Outdoor Insulation

Corona discharges and UV radiation on the surface of silicone rubber sheath are considered to be one of the ageing mechanisms responsible for the failure of composite insulators. An advanced high temperature vulcanized silicone rubber (HTV-SR) has been developed in Shemar to solve this issue. In this study, the ageing performance of HTV-SR specimens resulting from a 2000h UV radiation exposure and a corona discharge test were investigated; furthermore, physicochemical analyses were conducted on the specimens before and after the treatment. The results showed that the optimized formulation represented a very slight decrease in both electrical and mechanical performances. The hydrophobicity of all the specimens can restore to the nearly initial level after a short-term standing. It was demonstrated that the composite insulator with advanced HTV-SR sheath has long-term lifetime even operated under the extremely environmental and electrical stresses.