500kV交流输电线路含缺陷复合绝缘子电场分布特性研究

Electric Field Characteristics of 500kV AC Transmission Line with Defect Composite Insulators

500kV线路复合绝缘子应用量大,正确有效判别出含有缺陷的复合绝缘子,对于保障电网安全稳定运行意义重大。为此,基于有限元分析方法,建立了500kV交流输电线路复合绝缘子串三维有限元模型,计算了正常和含有单个导通性缺陷情况下的绝缘子和空间电场分布并归纳其特征,分析了导通性缺陷长度及位置对绝缘子电场分布和强度的影响。计算结果表明,当复合绝缘子串存在导通性缺陷时,电场强度分布曲线会出现有规律的畸变,该特征可为判断复合绝缘子是否存在导通性缺陷提供判断依据。

500kV AC transmission line composite insulators has been widely used in grid.Accurately detecting the defect of composite insulators is very important for ensuring the safe operation of grid.Based on the finite element analysis method,the three-dimensional model of 500kV EHV transmission line composite insulators was established.And then the space electric field intensity distribution curve along the insulator string of the normal insulators and insulator with single conductive defects were given.Analysis of the length and the position of conductive defects influence on the electric field distribution were also carried out.Calculation results show that the electric field intensity distribution curve will appear distortion apparently when the conductive defects exist in the insulators,and this character can be applied in the field test of composite insulators defects.