Gas-solid interface charge accumulation and the consequent decrease in surface flashover voltage have impeded the development of DC gas-insulated equipment. Investigation of the effect of insulating material on charge-induced surface discharges holds paramount importance in advancing high-performance insulation and enhancing the operational reliability of DC gas-insulated equipment. In this paper

an experimental platform for charge spot deposition and surface discharge is established. Then

the charge-induced surface discharge for three types of insulating materials

including polycarbonate (PC)

polymethyl methacrylate (PMMA)

and epoxy resin (EP) doped with Al2O3

are conducted. Additionally

the secondary electron emission yield (SEEY) and trap distribution of the insulating materials are measured

and the effect pattern and key factors of insulating materials on charge-induced surface discharges are obtained

along with the influence mechanism of microscopic parameters of insulating materials on surface discharge. The results indicate that the deposited positive charges inhibit the development of positive streamers

while deposited negative charges promote the development of positive streamers. Furthermore

the secondary electron emission yield of insulating materials mainly contributes to the residual charge density of streamer. As the trap energy level decreases

surface discharge in the insulating material becomes more likely. The sensitivity of streamer channels of insulation surface to the electric field is a crucial factor determining the effect of interface charges on surface discharge.