硅脂环境下硅橡胶的吸收特性及其关键电气性能研究

Absorption characteristics and key electrical properties of silicone rubber in silicone grease environment

电缆附件在长期运行过程中,其界面硅脂与绝缘硅橡胶直接接触使其逐渐被硅橡胶吸收,导致硅橡胶性能下降,甚至引发电缆附件界面问题。文中以附件绝缘硅橡胶吸收硅脂的增重试验为基础,研究不同温度下硅脂/硅油在硅橡胶中的扩散规律并获得相应的扩散参数;研究硅脂对硅橡胶体积电阻率、相对介电常数、介质损耗角正切值和工频击穿场强等电气性能的影响规律。结果表明,不同温度下硅脂/硅油在硅橡胶中的扩散规律服从Langmuir扩散模型;硅橡胶对硅脂/硅油的吸收能力随温度升高而增强,且硅橡胶内硅油分子的脱附过程更强;随着硅橡胶对硅脂吸收量的增加,硅橡胶的体积电阻率逐渐降低,相对介电常数和介质损耗角正切值逐渐增加,但其工频击穿场强呈先增大后减小的趋势。

During the long-term operation of cable accessories,the interface silicone grease is in direct contact with the insulation silicone rubber,so that it is gradually absorbed by the silicone rubber,resulting in the performance degradation of silicone rubber,and even the interface problems of cable accessories.Based on the weight increasing test of silicone rubber absorbing silicone grease for accessory insulation,the diffusion rules of silicone grease/silicone oil in silicone rubber at different temperatures are studied and the corresponding diffusion parameters are obtained.The influence of silicone grease on the electrical properties of silicone rubber,such as volume resistivity,relative dielectric constant,dielectric loss angle tangent value and power frequency breakdown field strength,is investigated.The results show that the diffusion law of silicone grease/silicone oil in silicone rubber follows the Langmuir diffusion model at different temperatures.The absorption capacity of silicone rubber to silicone grease/silicone oil increases with the increase of temperature,and the desorption process of silicone oil molecules in silicone rubber is stronger.With the increase of the absorption amount of silicone rubber to silicone grease,the volume resistivity of silicone rubber decreases gradually,the relative dielectric constant and the tangent value of the dielectric loss angle increase gradually,but the breakdown field strength of its power frequency first increases and then decreases.