大气环境对合成绝缘子的憎水性影响分析

Analysis of the Factors Effecting the Hydrophobicity of Composite Insulator in Atmosphere Condition

通过模拟不同的气候条件,试验分析了大气环境中影响合成绝缘子憎水性的各种因素,结果表明:分离水珠影响了硅橡胶表面的电场分布,局部小电弧导致了硅橡胶表面憎水性能的下降;合成绝缘子的憎水性随污秽层等值盐密的升高而降低,随污秽层附着时间的增长而增强,且酸性物质对合成绝缘子憎水性的影响较碱性物质影响小;低温特别是覆冰条件下,合成绝缘子的憎水性将减弱甚至丧失;随温度的升高,小分子聚合物挥发速度加快,硅橡胶的憎水性能越强,其老化速度加快。

This paper tests and analyzes the factors influencing the hydrophobicity of composite insulators under the different atmosphere conditions simulated in the laboratory. It indicates water drops can only accrete on the surface of silicone rubber at discrete form because of its hydrophobicity, and water drops affect the electric field distributing of Silicone Rubber Surface. The corona and partial discharge （PD） around water drops and the flashover between water drops lead to the loss of hydropbobicity. In this paper, it is experimentally proved that the hydrophobicity of pollutant layer is proportional with the time when it is attached on a silicon surface because the silicone rubber material makes the contaminant layer on the composite insulator hydrophobic through the volatilization of its low molecular weight polymer chains, and that it reduces with the increase of ESDD of pollutant layer attached on a silicon surface, however that acid pollutants has less influences on the hydrophobicity than alkali one. Composite insulator contains many white charcoal black having a strong hydrophilic property. It can soak moisture of air, and then also its reaction with water makes hydrogen bond. It is difficult to remove water from white charcoal black at low temperature, therefore at low temperature, especially under icing condition, the hydrophobicity of composite insulator degenerated gradually and even lost completely. The higher the temperature, the faster the dehydration and the volatilization of the low molecular weights （LMW）. The hydrophobicity of Silicone Rubber Surface become strong, but the hydropbobicity-aging speed of composite insulator increases.