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Systematic Study on Humidity Correction of Flashover Voltage of Insulators

绝缘子闪络电压湿度修正的系统研究

基本信息

批准号：
07455119
负责人：
NAITO Katsuhiko
金额：
$ 4.86万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455119/
关键词：
Insulator Flashover Absolute humidity Humidity correction Silicone rubber Hydrophobicity 汚損シリコーンゴム

项目摘要

Humidity correction prescribed in the existing IEC standard is based on the experimental results reported in 1950's : that is, flashover voltage of insulators increases with absolute humidity. A possibility is also pointed out that the existing correction is not adequate because it occasionally results in excessive correction and causes problems in commercial tests.Under these circumstances, effect of absolute humidity on 50% flashover voltage of various ceramic and a composite insulators was studied under natural conditions by applying ac, lightning or switching impulse or dc voltage. Hydrophobicity on the surface of composite insulator surface was also studied. The main results obtained are as follows :(1) The dates of experiments were selected according to the change of absolute humidity, which was recorded at the test site over three years.(2) For most of insulators, the existing IEC humidity correction seems to be proper regardless of kinds of applied voltage.(3) Change of humidity correction seems necessary for pin type and unit suspension disk insulators for positive and negative lightning impulse flashover voltage tests.(4) Water droplets on silicone rubber vibrate and stick to each other under voltage application, which results in lower flashober voltage.(5) Flashover voltage on contaminated silicone rubber increases gradually with time lapse after contamination. This phenomenon may be attributed to the recovery of hydrophobicity due to migration of low molecular weight silicone oil from the bulk to the surface.

现行IEC标准中规定的湿度修正是基于50年代的实验结果，即绝缘子的闪络电压随绝对湿度的增加而增加。在此情况下，研究了自然条件下，施加交流电压、雷电电压、操作冲击电压和直流电压时，绝对湿度对各种瓷绝缘子和合成绝缘子50%闪络电压的影响。研究了复合绝缘子表面的憎水性。主要研究结果如下：（1）试验日期的选择是根据试验地点三年内绝对湿度的变化来确定的。(2)对于大多数绝缘子，现有的IEC湿度校正似乎是适当的，无论施加的电压种类。(3)针式和单元悬式盘形绝缘子在进行正、负雷电冲击闪络电压试验时，需要改变湿度修正值。(4)硅橡胶上的水滴在电压作用下发生振动并相互粘附，从而降低了闪络电压。(5)硅橡胶污闪电压随时间的延长而逐渐增大。这种现象可能是由于低分子量硅油从本体迁移到表面而恢复了疏水性。