污秽和水分对瓷支柱绝缘子发热的影响

Pollution and Water Molecule Effects on Porcelain Post Insulator Heating

绝缘子表面污秽受潮和水分侵入瓷体均可导致瓷支柱绝缘子出现异常发热,比较二者所引起的温升规律具有重要的实际应用价值。为此,选取具有相同运行年限和气象环境条件的试品,发热试品在现场局部有明显发热,不发热试品表面温度分布均匀。研究结果表明：发热试品经干燥处理后发热点暂时性消失,浸泡后的试品温升最大值约为浸泡前数值的2倍,浸泡后高湿和自然风干两种状态下温升变化趋势一致,差值〈1℃。浸泡后的发热试品温升最大值出现在加压时长为180~240 min,浸泡时长〉72 h时的局部温升变化幅值增加不明显。不发热试品在退网、干燥处理等两种状态下各部位温升值均〈0.4℃,浸泡后在表面湿润状态下最大温升仅为1.2℃。发热试品表面污秽受潮湿润后的局部温升值远小于水分侵入瓷体后的温升值,浸泡前的发热试品热点位于7号伞瓷柱附近,浸泡后发热点迁移到3号伞瓷柱附近。发热试品异常发热系绝缘子低压端金具同瓷体胶装处有明显的裂纹和凹坑,该缺陷导致水分侵入瓷体后会引起瓷体局部出现异常发热。

Wet pollution and invasion of water can cause abnormal heating of post porcelain insulator. Comparison of the temperature rise laws has the value of practical application. Therefore, samples had the same production time, operating life, and running environment were selected to be the research objects. Sample A had obvious partial heat, while sample B had uniform temperature. The results show that the abnormal heating area of sample A disappears after drying. After soaking, the maximum value of temperature rise is about twice before soaking. The variation trend of temperature rise under the conditions of extreme wet and natural drying is consistent after soaking, and the difference is less than 1 ℃. Af- ter soaking, the maximum temperature rise of heating sample appears at 180-240 min on-load status. The change of the partial temperature rise is not obvious when the soaking time is longer than 72 h. All parts＇ temperature rise of normal sample is less than 0.4℃ under the condition of logout and drying. The maximum temperature rise under the status of wet surface after soaking is just 1.2℃. The partial temperature rise after the pollution on the surface of heating normal sample is far less than that after water invading into the porcelain body. The hot point of heating sample is near the 7th umbrella before soaking, while the point moves to the place near the 3rd umbrella after soaking. The abnormal heating of heating sample is caused by the crack and pit on the binding area of the low-voltage side fitting and porcelain body. These defects lead to the invasion of the water, and then partial abnormal heat appears.