Review of charge accumulation on spacers of gas insulated equipment at DC stress

Charge accumulation on the spacer surface in gas insulated equipment is very severe in the DC field, leading to easy flashover, which restricts the application of DC GIS/GIL. Therefore, knowledge about the charge accumulation characteristics of gas insulated equipment at DC stress is essential. In this paper, we reviewed the research methods and the characteristics of charge accumulation on spacers. A summary of charge measurement methods and setups are presented. And the surface charge inversion algorithms are introduced. Then the simulation model for charge accumulation in the DC field is reviewed. Subsequently, the charge accumulation mechanisms and phenomenon, the influence factor of surface charge accumulation and the influence of accumulated charge on spacer insulation characteristics are summarized. In addition, some suppression methods of surface charge accumulation are discussed. Finally, based on the understanding of charge accumulation on spacers, some suggestions on further studies are presented to aid in the design of a better spacer free from surface charges.