Optimization of Electric Field Distribution for Tri-Phase Tri-Post Insulator in 220kV GIL

摘要

With the increasing demand for energy and the shortage of land in big cities, the urban underground common trench has been paid more and more attention as a solution. Due to the advantages of high transmission performance and low land cost, the 220kV GIL is promising to be applied in the future. Three-phase tri-post insulator is a key component of 220kV GIL, whose insulation performance determines the safety and reliability of the whole power system. Therefore, it’s significant to optimize the structure of post insulation. In this paper, a model of 220kV GIL is established in SolidWorks, which includes 3 center conductors, a three-phase tri-post insulator, metal shells, etc. Then the potential and electric field distribution of the insulator are calculated with finite element methods in COMSOL Multiphysics. The maximum field value on the insulator’s surface is distributed at the sphere zone while that on the surface of metal insert is distributed at the chamfer. On this basis, choosing the maximum values of the field strength on the key positions of the insulator as indexes, the influence of key parameters on electric field distribution is obtained. The results indicate that different key parameters have different effects on electric field distribution. The conclusion of this paper could provide reference and guidance for the design of 220kV three-phase tri-post insulator.