Numerical Study on the Spatiotemporal Evolution of SF6 Streamer Discharge Induced by Multimetallic Particles

SF6 gas is commonly used in gas-insulated switchgear (GIS). However, metallic particles in GIS devices can cause insulation failures by inducing partial discharges under a high electric field, thereby threatening system performance and operational safety. This study examines the streamer discharge process induced by multimetallic particles in SF6 gas and its spatiotemporal evolution. A two-dimensional plate-plate electrode model was used to analyze the effects of particle quantity and positional deviations on discharge characteristics. The results show that electric field superposition and charge interactions between particles accelerate streamer development and influence the discharge direction. Increasing particle quantity and reducing particle size weaken the electric field coupling effects between particles, thereby delaying the development of positive streamers. The positional deviations of metallic particles influence the tip effect of the electric field between particles, which in turn determines the propagation path and discharge characteristics of the streamer. A moderate lateral displacement promotes discharge, while excessive displacement weakens coupling and suppresses streamer growth. This study offers insights for optimizing SF6 insulation systems and preventing GIS failures.