支柱绝缘子上下表面不均匀积污负极性直流闪络特性  

Negative DC Flashover Performance of Post Insulators with Non-uniform Pollution on Top and Bottom Surfaces

作　　者：张志劲[1] 李汛 乔新涵 蒋兴良[1] ZHANG Zhijin;LI Xun;QIAO Xinhan;JIANG Xingliang(State Key Laboratory of Power Transmission Equipment&System Security and New Technology,Chongqing University,Chongqing 400030,China)

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400030

出　　处：《高电压技术》2020年第10期3569-3575,共7页High Voltage Engineering

基　　金：国家重点研发计划(2016YFB0900900)。

摘　　要：支柱瓷绝缘子在直流换流站得到普遍使用,近年的研究表明支柱瓷绝缘子的积污特性为上表面积污较下表面严重。对ZSW56-126/8绝缘子采用人工涂污法进行该积污特性下的直流闪络特性进行研究,试验得到各不均匀度下的闪络电压,用最小二乘法拟合闪络电压与盐密的关系,得出上下表面不均匀积污的直流闪络特性。分析了不均匀积污对绝缘子表面电导率的影响,得到了等值电导率关于不均匀度的函数。基于等值电导率函数推导出不均匀污秽闪络电压修正系数理论表达式,通过比对试验结果进行了校验,为不均匀污秽闪络电压变化提供了理论依据。同时,对比分析了修正系数经验公式,拟合得到带修正系数闪络电压表达式,通过误差计算进行了校验。可得如下结论:支柱绝缘子上下表面不均匀积污情况下,直流闪络电压Uf和盐密ρSDD满足经验公式Uf=aρSDD^-b,系数a与不均匀度正相关,且a随不均匀度的增加而变大,指数b值不受不均匀度的影响;支柱绝缘子上下表面不均匀积污将影响其表面污层电导率,进而影响其闪络电压。Porcelain post insulators have been widely used in DC converter stations.Recent studies have shown that the pollution of the top surface is heavier than that of the bottom surface.The ZSW56-126/8 insulator was artificially contaminated to study the DC flashover characteristics under the non-uniform pollution,and the flashover voltage under each non-uniformity was obtained.The relationship between the flashover voltage and the salt density was fitted by the least squares method,and the DC flashover characteristics of the non-uniform pollution were obtained.Furthermore,the influence of non-uniform pollution on the surface conductivity of the insulator was analyzed,and the equivalent conductivity was obtained as a function of the non-uniformity.Based on the equivalent conductivity function,the theoretical expression of the non-uniform pollution flashover voltage correction coefficient was derived and verified,providing a theoretical basis for the non-uniform pollution flashover voltage variation.Meanwhile,the empirical formula of the correction coefficient was analyzed,and the expression of the flashover voltage with the correction coefficient was obtained and verified by error calculation.It can concluded that the empirical formula of DC flashover voltage Uf and salt densityρSDD can be obtained as:Uf=aρSDD^-b positively correlated with the inhomogeneity,the a increases with the increase of the inhomogeneity,and the index b value is not affected by the inhomogeneity.Non-uniform pollution on the upper and lower surfaces of the pillar insulators will affect the conductivity of the surface fouling layer and then the flashover voltage.

关 键 词：支柱绝缘子 直流 不均匀污秽 表面电导率 闪络电压 

分 类 号：TM216[一般工业技术—材料科学与工程]