500kV六氟化硫绝缘罐式金属氧化物避雷器电场分析

Electric Field Analysis of 500 kV Tank Type Metal Oxide Surge Arresters

无间隙金属氧化物避雷器(WGMOA)在通常工作情况下电压沿轴线分布不均匀。承担电压较大的电阻片同时承担较大的热应力,这样就会加速这些电阻片的劣化。因此,改善避雷器电压沿轴线分布使其更加均匀,就显得十分必要。避雷器电阻片的电压分布主要取决于避雷器几何结构和采用的材料两个方面。笔者采用有限元数值计算方法,通过建立3 D模型对500 kVGIS用一相一罐式金属氧化物避雷器内部电场强度分布进行了计算。就均压罩各个参数对避雷器电阻片电压偏差的影响进行讨论,并通过优化均压环参数将避雷器整体电压偏差限制在-10%～+10%之间。

The latitudinal voltage distribution along metel-oxide surge arrester without gaps （WGMOA） under normal operating conditions is non-uniform. The discs with higher voltage stress are subjected to stronger thermal stresses, leading to a faster thermal ageing of these highly stressed discs. Therefore, efforts are generally made to make the latitudinal voltage distribution as uniform as possible. The voltage distribution in the arrester is governed by the geometry as well as the electrical properties of the materials used. The electrical fields distribution of singe phase tank type metal oxide surge arrester for 500 kV GIS is computed using finite element method. The influence of grading shield and electrical properties of the materials used to the voltage distribution ratios of zinc oxide elements is discussed. The voltage stress distribution variation along the whole surge arrester can be limited withjn -10%～＋10% through optimizing grading ring parameters.