电阻片电容量对500kV罐式避雷器电位分布的影响

Influence of Resister Disc's Capacity to Potential Distribution in Tank Type Metal Oxide Surge Arresters for 500 kV GIS

无间隙金属氧化物避雷器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,这样会加速电阻片的劣化。因此,改善避雷器电压沿轴线分布,使其分布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2个方面。通过建立3D有限元模型,对500 kV GIS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,从均压环和避雷器电阻片主电容2个方面进行讨论,并给出一套合理的均压措施。

The potential distribution in a zinc oxide surge arrester under normal operating conditions has been observed to be nonuniform. The discs with higher voltage are subjected to stronger thermal stresses, leading to the faster thermal ageing of these highly stressed discs. Therefore, efforts are generally made to make the potential distribution as uniform as possible. The potential distribution in the an＇ester is governed by the geometry as well as the electrical properties of used materials. In this paper, the electrical field distribution of one phase in one tank type metal oxide surge arrester for 500 kV GIS is computed using 3D finite element model. The influence of grading hoop and electrical properties of the used materials to the voltage distribution ratios of zinc oxide elements is discussed, and specific measures for pressure balancing are given.