复合绝缘子污层弱憎水性条件下的表面水滴形态

Water Droplet Shape on Surfaces of Composite Insulators with Contamination Under Unobvious Hydrophobic State

研究固体污层法中复合绝缘子表面的弱憎水性污层对高压线设计优化具有重要意义。采用调节污层惰性成分中硅藻土和高岭土的质量比实现对迁移一定时间后污层表面憎水性的微调,得到经过细分的亲水性及弱憎水性污秽。本文观察了不同成分污层表面水滴的形态变化且针对具有不同成分污层的复合绝缘子,并进行人工污秽试验。利用傅里叶变换红外光谱分析手段实现对迁移前后弱憎水性污层中小分子扩散情况的检测。试验结果表明:复合绝缘子表面污层呈弱憎水性时,虽然传统的憎水性表征——喷水分级及静态接触角测量结果同完全亲水性时相似,但内部出现了明显的憎水性小分子迁移现象。这些小分子出现在污层内部的后果是对水滴渗入污层过程产生抑制作用,该抑制作用会对水滴在污层表面扩散过程中的形态产生影响。进一步地,这些影响还将在污闪试验中妨碍盐分的浸出,使闪络电压升高。

Study on the property of a unobvious hydrophobic contaminated layer on the surface of composite insulators by the solid layer method is of great significance for transmission line designing. The hydrophobicity of the surface of migrated insulators for a certain period of time was adjusted by adjusting the proportion of diatomite and kaolin in the artificial contamination. In this way, contamination under hydrophilic and unobvious hydrophobic conditions were obtained. Changing of the shape of water droplets on the surface under different conditions were observed. Flashover test was carried out on composite insulators with different compositions. The detection of small molecule diffusion in unobvious hydrophobic contamination before and after migration was observed by Fourier transform infrared spectroscopy. The results show that, under unobvious hydrophobic condition, although the traditional hydrophobic characterization-water spray method and static contact angle result are basically the same as the complete hydrophilic condition, low molecule weight migration is observed. The consequence of these low molecule weight in contaminated layer is the inhibition of the infiltration of water droplets into soil, which will affect the shape variation of the water droplets during the surface diffusion process. Furthermore, these effects will also prevent leaching of salts in the flashover test, leading to increase in flashover voltage.