不同涂覆效果下复合化盘形悬式绝缘子电气性能差异分析

Analysis on Electric Performance Differences of Composite Cap and Pin Insulators under Different Coating Effects

在盘形悬式绝缘子表面涂覆RTV涂料是一种极为有效的防污闪措施。但由于施工、制造过程没有统一标准,导致实际运行的绝缘子产品表面涂覆效果差异较大,如有的涂料把铁帽覆盖住,有的涂料未覆盖绝缘子上表面等。不同涂覆效果可能会直接影响绝缘子的电气特性。以三种典型不同涂覆试品为对象,在国家电网公司重点实验室分别进行油中击穿耐受电压试验、直流干闪络电压试验,同时,通过ANSYS仿真软件,对试品分别建模分析场强分布情况。结果显示:当RTV涂层上边缘正好与铁帽和瓷件的结合处重合时,其直流干闪络电压最低,油中击穿试验更多体现为伞裙击穿,并且击穿电压相对更低。建议绝缘子进行RTV涂覆时,铁帽底部周围保持一定环形空隙。

To use the RTV coating is an effective anti-pollution flashover method on the surface of the cap and pin insulators. However, without unified standard on construction and manufacturing process, the differences of RTV coating effect of actual operating insulators are large. For example, some insulators＇ caps may be covered by RTV, while others＇ upper surface may not be covered by RTV totally. Different coating effects may directly affect the electrical characteristics of the insulators. Oil power frequency puncture test and DC dry flashover voltage test were carried out respectively on samples with three different coating effects in the key laboratory of State Grid Corporation,. Meanwhile, these three kinds of samples were modeled to analyze the electric field distributions using the ANSYS simulation software. The results show that the DC dry flashover voltage is the lowest, and the puncture voltage is relatively lower with the shed more possibly punctured when the insulator＇ s upper edge of the RTV coating coincides with the combination of the iron cap and the porcelain pieces. It is recommended that the edge of RTV coating shall keep a certain distance from the bottom of the iron cao while coating the insulator.