浙江电网架空输电线路绝缘子串的自然积污特性

Natural Pollution Accumulation Characteristics of Overhead Transmission Line Insulator Strings of Zhejiang Electric Power Grid

掌握自然积污绝缘子的积污特性是绘制污秽区域分布图的重要依据。因此,以浙江电网架空输电线路绝缘子串为对象,对自然积污绝缘子的积污特点进行了试验研究。采用数量统计方法分析了上、下表面的等值灰密(NSDD)、等值盐密(ESDD)积污比KNSDD、KESDD以及2者比值KNSDD/ESDD的分布规律,并对不同污染源下绝缘子表面污秽物化学成分进行了分析。结果表明:不同结构型式自然积污绝缘子上、下表面污秽分布的不均匀特性存在差异;自然积污绝缘子KNSDD/ESDD的平均值为4.66,整片绝缘子KNSDD/ESDD平均值的变化趋势与下表面KNSDD/ESDD的变化趋势基本一致;绝缘子表面污秽物中,Ca2+占全部阳离子的摩尔分数最高,SO42-占全部阴离子的摩尔分数最高;同一片绝缘子,上、下表面污秽中各种离子的摩尔分数存在一定差异。建议外绝缘设计及线路运行维护中充分考虑这些积污特点。

The characteristics of pollution accumulation on naturally polluted insulators are fundamental for drawing pollutant distribution maps for power systems. Hence, taking some insulator strings on Zhejiang overhead transmission lines as samples, we investigated the natural pollution accumulation of insulators. Using statistical methods, we obtained and analyzed the ratio of top pollution level to bottom pollution level in aspects of equivalent salt deposition density （ESDD）, non-soluble deposition density （NSDD）, and the ratio between the two, which were denoted by KESDD, KNSDD and KNSDD/ESOD , respectively. Besides, we also analyzed the chemical compositions of the contamination under typical pollution resources. The results show that, for insulators of different structures, their top and bottom surfaces have quite different unevenness of pollution accumulation. For a naturally polluted insulator, the average value of ratio of KNSDD/ESDD is 4.66, while on a whole piece of insulator, the distribution of average KNSDD/ESDO varies in a tendency approximately consistent with that of the piece＇s bottom surface. In the contamination under study, Ca2＋ is the main component of ca- tions and SO42 is the main component of anions. For a piece of insulator, the proportion of different ions on its top surface is different from that of its bottom surface. It is recommended that these features of pollution deposit should be adequately considered in outdoor insulation designing and operation maintenance.