220kV复合横担新型塔均压环电场分析

Electric Field Analysis of Grading Ring for 220kV New Type Tower With Composite Cross-arm

针对复合横担新型杆塔开展均压环设计研究,应用有限元计算软件,建立220kV复合横担新型杆塔三维有限元计算模型,采用在计算模型中不断调整均压环结构参数(管径、环径、罩入深度)的方法,从控制电场强度的角度出发得到优化的均压环设计方案。通过校核计算表明:安装均压环后,三相横担支柱绝缘子和斜拉绝缘子表面的电场和电位分布得到有效改善,金具表面的最大场强得到大幅度降低,金具法兰处存在尖角结构,使场强在尖角处集中,场强值略高于场强控制值20kV/cm。采用对尖角部位倒角处理,倒角处理后,金具表面最大场强控制在允许范围内。因此,设计合理的均压环参数并结合金具尖角倒角处理的设计方法可以满足220kV复合横担新型杆塔均压设计要求。

Design of grading rings for a 220kV new-type tower with composite cross-arms is studied. A 3D finite element model of the whole tower is established by finite element software to analyze the parameters of grading ring. In order to control the electric field strength,the structure parameters including pipe diameter,ring diameter and covering depth are adjusted to obtain an optimal design scheme for the grading ring. The computed results show that the electric field and potential distributions on the surface of horizontally post insulators and diagonally tension insulators can be improved effectively,and the maximum electric field strength on the end fitting surface can be reduced obviously. However,the sharp edge of the metal flange leads to locally intensified electric field strength,which is slightly higher than the controlled value of 20kV/cm. After reasonable chamfering processing,the maximum electric field strength can be controlled within the desired scope. Therefore,the final design proposal can meet the technical requirements of 220kV new-type tower with composite cross-arm by means of parameter optimization for grading ring and end fitting and chamfering processing of the sharp edge of the metal flange