绝缘材料表面污秽颗粒微观分布规律

Microscopic Distribution of Polluted Particles on the Surface of Insulating Materials

绝缘子是输电线路的重要组成元件,其污秽集聚特性会影响绝缘子的外绝缘性能,是外绝缘配置的依据之一。为研究不同材料绝缘子表面积污规律,探明绝缘子表面积污机理,通过人工气雾室对不同绝缘子材料进行人工积污试验,通过光学显微镜对表面污秽形貌进行观测,同时使用正射图像投影法对污秽粒径分布进行统计。研究结果表明,2种材料表面污秽颗粒粒径分布相似,玻璃绝缘材料表面污秽粒径略大于相同环境下复合绝缘子表面;随着电极两端电压增加,绝缘子表面污秽粒径均会增加;同时可以发现,表面污秽形貌分布存在明显区别:复合绝缘材料表面污秽形貌呈紧凑的链状结构,玻璃绝缘材料表面污秽结构呈松散的堆状结构。通过对污秽颗粒进行受力分析,基于热力学理论及气溶胶团聚理论,结合绝缘子表面电位测试结果,认为造成绝缘材料表面形貌不同的主要原因是电场环境中材料表面所带电荷量的不同以及表面憎水性不同。

Insulator is an important component of transmission line,and its pollution accumulation characteristics affect the insulation characteristics of the insulator.This is one of the bases for external insulation configuration.In order to study the surface pollution law of insulators of different materials and find out the mechanism of surface pollution of insulators,this paper uses artificial aerosol chamber to carry out artificial pollution test on different insulator materials,observe the surface pollution morphology with optical microscope,and use orthophoto projection method to stat contamination particle size distribution.Results show that the particle size distribution on the surfaces of two materials is similar.The surface contamination of glass insulation material is slightly higher than that of composite insulator under the same environment.As the voltage across electrodes increases,the contamination particle size on the insulator surface increases.At the same time,there is a significant difference in the distribution of surface pollution morphology.The surface of composite insulating material has a compact chain structure,and the surface of glass insulating material has a loose pile structure.Through force analysis of contaminating particles,based on thermodynamic theory and aerosol agglomeration theory and combined with the insulator surface potential test results,the main reason for the difference in the surface topography of the insulating materials is that the amount of charge on the surface of the materials in electric field environment and surface hydrophobicity are different.