±500 kV葛南线绝缘子自然积污特性研究

A study of natural contamination characteristics of insulators on±500 kV Gezhouba-Nanqiao HVDC transmission lines

为研究直流线路绝缘子的自然积污特性,在±500 kV葛南线浙江嘉兴与湖州段设置测点进行自然积污试验。测试得到了绝缘子的等值盐密与等值灰密,研究了电场与伞形对绝缘子积污特性的影响,结果表明:钟罩型绝缘子积污比双伞形严重,钟罩型盐密、灰密平均为双伞形的1.73、1.54倍,灰盐比钟罩型略大,双伞形积污不均匀度显著小于钟罩型。提出了一种考虑积污不均匀度与灰密的绝缘子爬距有效利用系数计算方法,计算了不同污区等级下XZWP-160绝缘子的爬距有效利用系数。研究结果可为预防线路污闪事故提供有益参考。

To study the natural contamination characteristics of insulators on DC lines,measurement points are set between sections Jiaxing and Huzhou of ±500 kV Gezhouba-Nanqiao HVDC transmission lines to carry out natural contamination tests.The equivalent salt deposit density(ESDD)and non-soluble deposit density(NSDD)of insulators are obtained through tests.Also,the effect of electric field and shed shapes on the contamination characteristics of insulators is studied.The results show that the bell-shaped insulators are more susceptible to contamination in contrast to double-shed ones;the ESDD and NSDD of a bell-shaped insulator are 1.73 and 1.54 times respectively as much as those of the double-shed one;the NSDD/ESDD ratio of a double-shed insulator is slightly smaller than that of a bell-shaped one,and the contamination unevenness of a double-shed insulator is far smaller than that of the latter.Finally,a method for calculating the effective utilization coefficient of insulator creepage distance considering contamination unevenness and NSDD is proposed,and the effective utilization coefficients of the creepage distances of XZWP-160 insulators under different contamination levels are calculated.The research results can be a beneficial reference for line flashover prevention.