Surface Charge Effect on the Electric Field Distribution of Tri-Post Insulator used in ±800kV DC Wall Bushing

Abstract

Charge accumulation on the gas-solid interface of insulator inside the SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> gas insulated equipment in DC systems may affects the electric field distribution near the insulator. In order to investigate the surface charge effect of tri-post insulator used in a ± 800kV gas insulated HVDC wall bushing This paper studies the surface charge distribution of the tri-post insulator near the wall bushing flange and its effect on the electric field by finite element method. The model is established in actual size. By taking the non-linear conductive processes of SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> into consideration, the electric field and surface charge distribution under DC voltages are calculated. This research can provide an important guidance for the structural design and fault diagnosis for tri-post insulators used in HVDC wall bushing.