Electrical insulation performance of HVDC-GIS spacer under various testing conditions

In this paper, by using the Finite Element Method (FEM), electric field and charge density distributions of epoxyspacer in actual 500 kV DC gas insulated switchgear (DC-GIS) structures are calculated, while adjusting parameters such as inclination angle and thickness of the core-spacer. In addition, we discussed the electrical insulation performance under AC, DC steady-state, and DC polarity reversal (DC-PR) testing conditions based on actual 500 kV DC-GIS structures. As a result, we clarified that the accumulated charges on a solid insulator surface under DC steady-state can be a critical parameter to determine the maximum electric field distribution at DC-PR conditions. Further more, we concluded that the electric field stress on the electrode surface of the spacer at DC-PR testing conditions has the severest impact on electrical insulation performance among the other tested conditions.