Surface Roughness of Conductor Affecting Surface Charge Distribution of Real-Sized DC GIS/GIL Insulator

Direct current gas-insulated switchgear (GIS/GIL) stands as a pivotal apparatus within high-voltage direct current (HVDC) transmission systems, exerting a paramount influence on achieving long-distance, high-reliability, high-capacity power transmission, and fostering the development of clean energy sources. However, during prolonged energized operation in DC systems, the issue of surface charge accumulation on insulators emerges as a critical factor leading to insulation breakdown. In this paper, based on a ±550 KV DC GIS prototype, a real-sized platform for measuring surface charges on bushing insulators was established. This study explores the influence of different surface roughness of the central electrode on the surface charge distribution of bushing insulators under varying gas environments. The results indicate that electrode roughness primarily affects the generation of localized charges.