Surface Charge Properties of Epoxy Composites under DC Voltage Affected by Surface and Bulk Conductivity

Qian Wang, Xidong Liang, Ke Chen, Chao Wu and Shan Liu
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Qian Wang: State Key Laboratory of Power System and Generation Equipment, Tsinghua University, Beijing 100084, China
Xidong Liang: State Key Laboratory of Power System and Generation Equipment, Tsinghua University, Beijing 100084, China
Ke Chen: Hubei Economic Research Institute, State Grid Corporation of China, Wuhan 430000, China
Chao Wu: Electrical Insulation Research Center, University of Connecticut, Storrs, CT 06269, USA
Shan Liu: Global Energy Interconnection Research Institute, State Grid Corporation of China, Beijing 102209, China

Energies, 2021, vol. 14, issue 2, 1-12

Abstract: As DC transmission voltage increases, the DC wall bushing becomes longer, and a supporting insulator is introduced to keep the conductor straight. Under extremely high electric fields coupled with a thermal gradient, the surface charge of the supporting insulator may distort the field distribution and increase the risk of flashover. In this paper, surface potentials of three model epoxy resin composites were systematically investigated under varied voltage amplitudes, different voltage polarities and electric field distributions. The bulk and surface resistivity of the epoxy resin composites over a broad temperature range were measured to reveal the correlations between surface charge and such basic electrical parameters. The results indicate that the normal-dominated electric field plays the major role in charge accumulation. The processes of surface charge accumulation and dissipation are more closely related to the surface resistivity. As a result, the surface charge properties can be improved by optimizing the electrode structure and resistivity of the epoxy resin composites.

Keywords: charge accumulation; surface potential; surface resistivity; normal-dominated electric field (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
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