Dielectric Performance of Improved Gas Insulated Bushing for UHV Gis

This paper describes a improved gas insulated bushing for ultra high voltage (UHV) SF6 gas insulated switchgear (GIS) which contains a simple capacitor core inside a porcelain housing. The effects of arrangement and capacitance of the capacitor core on the voltage distribution along the external porcelain surface were analyzed, and a 2/3 scale model of a prototype UHV gas insulated bushing (6.7m porcelain housing) was developed. Characteristics tests of the voltage distribution and dielectric withstand voltage indicated that the voltage distribution was greatly improved and the dielectric withstand voltage of the switching impulse under wet conditions was enhanced about 30% compared with a conventional gas insulated bushing.