Study on Influencing Factors of Streamer Bifurcation Phenomenon in UHV GIS Disconnector Based on Phase-Field Method

Breakdown to ground in UHV GIS is a serious insulation fault. Streamer bifurcation phenomenon is a key factor to form secondary streamer breakdown to ground in UHV GIS disconnector. By setting the development direction of phase transition equivalent to the development direction of discharge streamer, this paper establishes a streamer discharge model of GIS disconnector based on phase-field method to study the characteristics and influencing factors of streamer bifurcation. Meanwhile, the different types of streamer bifurcation are discussed. Then, the possibility of secondary streamer breakdown to ground is analyzed by comparing streamer bifurcation area and shielding area. Furthermore, the shielding area is compared by different distance between two contacts, size of shielding cover and voltage level, to explore the influence factors of the formation of phenomenon that secondary streamer breakdown to ground. The study provides a theoretical basis of the ground breakdown fault causing by streamer bifurcation in GIS disconnector.