特高压GIS复合套管局部放电的检测和消除

Detection and Elimination on Partial Discharges in Composite Bushing for UHV GIS

复合套管具有抗湿闪、防爆、重量轻和成本低的特点,在特高压GIS中得到了广泛应用。在特高压GIS复合套管的研制中,出现局部放电超标问题,文中通过对局部放电现象和规律的分析,以及局部放电定位,确定了局部放电发生在套管空心绝缘子对应于内部屏蔽系统的位置;通过电场分析,确定了屏蔽系统附近电场分布设计的缺陷导致了局部放电;通过改进屏蔽系统结构和优化电场分布,使得套管伞裙的最大场强从0.49 kV/mm减小到0.26 kV/mm,有效消除了局部放电,实现了良好的工程应用。

Composite bushing is used widely in ultra-high voltage(UHV)GIS due to its such advantages as anti-wetflashover,anti-explosion,light weight and low cost.In the development of composite bushing for UHV GIS,the problem of partial discharge exceeding standard is encountered.In this paper,it is confirmed by way of analysis of partial discharge phenomenon and laws as well as location of the partial discharge that the partial discharge occurs at the position of the composite hollow insulator corresponding to the internal shield system.Moreover,it is confirmed through electric field analysis that the defect of electric field distribution design of the shield system near the shield leads to partial discharge.The improvement of system of shield structure and optimization of electric field distribution keeps the maximum electric field intensity of the shed of the bushing reduce from 0.49 kV/mm to 0.26 kV/mm,which eliminates effectively the partial discharge and achieves perfect practical application.