硅橡胶绝缘子污秽有效等值盐密及测量方法

Concept and Test Method of Effective Equivalent Salt Deposit Density for Silicone Rubber Composite Insulators

由于憎水性的存在，硅橡胶绝缘子污秽中的盐分浸出（溶出）过程将比亲水性的无机材料绝缘子的更为复杂，需对硅橡胶绝缘子污秽盐分浸出过程及浸出的盐分量进行研究。为此提出硅橡胶绝缘子的有效等值附盐密度（effective equivalent salt deposit density，EESDD）的概念，用以表征硅橡胶绝缘子不同憎水性污秽层在受潮过程中的实际盐分溶出量，并提出了一种结合憎水性分级测试且便于实际操作的EESDD测量方法。人工污秽层与现场硅橡胶绝缘子污秽层的EESDD测量结果表明：相同憎水性污秽层的有效溶出盐分是等值附盐密度（equivalent salt deposit density，ESDD）所测得盐分的一部分，硅橡胶绝缘子EESDD与ESDD的比值约为50％～90％，且该比值随污秽层憎水性下降而升高，并且同类型污秽灰密与盐密之比较低（〈4）时，其EESDD值相对较高。基于试验结果的分析指出，硅橡胶绝缘子污秽度测量应与其表面憎水性相结合，其爬电距离的配置应参考湿污秽层的有效等值附盐密度来确定。

Since silicon rubber insulator （SRI） has hydrophobicity, its salt dissolving in pollution is more complicated than that of insulators of hydrophilic inorganic materials. Therefore it is necessary to study the leaching process, as well as the amount of salt in the process, on wet polluted SRIs. We proposed the effective equivalent salt deposit density （EESDD） to characterize the amount of dissolved salt of different wet pollution layers on SRIs. We also designed a convenient method for testing EESDD, which included hydrophobic grading measurements. EESDD test results of both artificial and natural contaminated SRIs show that EESDD is a part of ESDD： the ratio between EESDD and ESDD is generally within 50% - 90 % and it increases with the reduction of pollution hydrophobicity. The EESDD is relatively larger when the ratio of NSDD and ESDD is less than 4. Based on the analysis of test results, it is suggested that the pollution test should be combined with hydrophobicity measurements of SRIs, and the dimensioning of SRIs should be based on EESDD rather than the site map of ceramic insulators.