Residual Charges on Barrier Surface Revealed by Potential Distribution in a Hybrid Gas-Solid Insulation System

The characteristics of residual charges on the inserted barrier surfaces in different air-insulated insulation systems after alternating breakdowns are investigated. High voltage withstand tests and surface potential measurements were carried out. The results show that the potential polarity on the barrier surface is related to the voltage polarity at the moment of breakdown. The barrier surface potential where the discharge passes through is lower. Compared with the barrier position, the electrode radius has a more significant effect on the surface potential distribution after breakdown. As the electrode radius increases, the positive surface potential is higher and the area with the potential higher than 3 kV is larger. The surface potential decays slowly when the barrier is suspended. At last, the effect of residual charges revealed by the surface potential is discussed.