电晕放电加速硅脂劣化对硅橡胶绝缘表面性能的影响

Silicone grease is widely used for surface lubrication and sealing in cable accessories installation. However, the insulation of cable accessories is affected by the swelling of silicone grease for a long time, where the surface discharge even interface breakdown easily occurs. So far the literature on the influence of different silicone greases with corona aging on interfacial electrical property and mechanical properties of silicone rubber is not available. Therefore, six kinds of silicone greases were selected for studying the changes of surface roughness, molecular groups and cross-linking structure, interfacial breakdown voltage and mechanical properties of silicone rubber coated with different silicone greases under corona aging. The results show that corona aging can destroy the surface morphology of silicone grease, silicone rubber, and its crosslinked structure, resulting in serious decrease in interfacial dielectric strength and mechanical properties of silicone rubber. Additionally, the cracks, holes and polar molecules on the surface of silicone grease and silicone rubber will increase the surface roughness of the coated sample, with which the interfacial breakdown voltage of XLPE/SR composite sample is negatively correlated, namely, the sample coated with a higher surface roughness has a lower interfacial breakdown voltage. Furthermore, a simple performance test of silicone grease can be provided as follows: some better silicon grease can be selected by performing the experiments for electrical and mechanical properties of silicone rubber coated with different silicone grease under corona aging.