Plasma Etching Constructs Step Gradient Surface Conductivity to Improve the Insulation Properties of Epoxy Resin

This article combines simulation and experiment to construct a transient field model for gas-solid composite insulation. Nonlinear gas conductivity, which is constructed by ion transport, combines with material intrinsic and surface conduction to explore the electrical properties of epoxy resin (EP) under step gradient surface conductivity (SGSC). SGSC controls the maximum charge density at the triple junction, reduces the total surface charge, alleviates the maximum field strength, homogenizes the electric field distribution, and suppresses power losses caused by leakage currents. Atmospheric pressure plasma jet (APPJ) step gradient surface etching platform was utilized to modify the EP sample, and the surface insulation performance was tested. The existence of an SGSC significantly enhances the material's flashover performance by accelerating surface charge dissipation in high-field strength regions while controlling the rate in low-field strength areas. The experimental results are consistent with the simulation.