高压电缆附件用硅橡胶材料电气特性研究OA

To investigate the variation in electrical properties of silicone rubber insulating materials coated with silicone grease at different thermal aging stages,silicone rubber samples coated with different types of silicone grease were subjected to thermal aging treatments at various temperatures and for different durations.The temperature-dependent conductivity,relative permittivity,dielectric loss tangent,and breakdown field strength of each sample under different aging conditions were measured.The results indicate that thermal aging causes degradation reactions such as chain scission and oxidation in the silicone rubber molecular chains,destroying the original cross-linked network structure and affecting the electrical properties of the silicone rubber insulation.This leads to an increase in conductivity,a rise in relative permittivity and dielectric loss tangent,and a reduction in insulation breakdown strength.During thermal aging,silicone rubber samples coated with silicone grease exhibit a swelling effect,which introduces a large number of short molecular chains similar to the main chain structure into the silicone rubber.These short chains undergo chemical reactions with the main molecular chains of the silicone rubber,leading to main chain scission,an increase in free volume and free electron concentration,and accelerated degradation of the silicone rubber insulation.The type of silicone grease used has a varying impact on the electrical properties of the silicone rubber samples.Among them,methylphenyl silicone grease is less prone to swelling with the silicone rubber molecules,so the electrical properties of silicone rubber samples coated with methylphenyl silicone grease are superior to those of samples coated with dimethyl silicone grease.