Effect of Silicone Grease on the Dielectric Property of Silicone Rubber for Cable Joint

Silicone grease helps lubricate and seal the cable joint interface during cable installation. However, silicone grease causes silicone rubber to swell during cable operation, which is an important factor| causing silicone rubber deterioration and equipment failure. In this paper, experiments are designed to study the effect of silicone grease on the dielectric properties of silicone rubber in cable joints. First, the dielectric properties of silicone grease absorbing different silicone rubbers in a wide frequency range were measured by using a broadband dielectric spectrum. Then, the experimental results are analyzed from the microscopic point of view by molecular dynamics simulation. It is found that dimethyl silicone grease can improve the charging properties of silicone rubber. Fluorinated silicone grease and long-chain alkanes deteriorate the charging properties of silicone rubber, and fluorinated silicone grease has the most obvious effect on the deterioration of the properties of silicone rubber. As the viscosity of dimethyl silicone grease decreases, its improvement on the dielectric properties of silicone rubber is more obvious. Therefore, the influence of silicone grease on the dielectric properties of silicone rubber is not only related to the molecular polarity of the silicone grease itself, but also to the swelling properties of the silicone grease.