Study on Electric Field Distortion Effect by Linear Defects of Tri-post Insulator

Gas insulated metal enclosed transmission line (GIL) is widely used in power transmission because of its prefect security and reliability. Tir-post insulator is one of the most important component in GIL which supports the insulation and structure. However, defects of tri-post insulator will distort the electric field distribution, weakened the insulation, even cause the insulation failure. The safety will be threatened by the defects. So it necessary to analyze the effect law of the electrical field distribution by defects, and focus on the severe place which is in the most need to avoid defects in production process. In this paper, a part of GIL model was built by using COMSOL Multiphysics which included the tri-post insulator. Two kinds of linear defects which may easily occur on tri-post insulator were researched. Result shows that the linear defects have different influence on electric field distribution in varying degree and indicates the effect laws of distortion with position and size of defects.