Effects of the Irradiation Energy and Irradiation Duration of Electron Beam on the Surface Flashover Voltage of Epoxy Composites

The occurrence of surface flashover at the interface between gas and solid insulation can compromise the safe and reliable operation of power equipment. Therefore, improving surface flashover voltage is crucial. This study examines the impact of electron beam irradiation energy and duration on surface flashover properties of the epoxy insulator. the irradiation energy or duration increases, the surface flashover voltage initially rises then falls. The maximum increase in flashover voltage, in comparison to the unirradiated sample, exceeds 12%. The effects of irradiation energy and irradiation duration on surface flashover voltage are similar, suggesting that the energy and the duration are interchangeable to a certain extent. This insight is instrumental in identifying optimal irradiation conditions for various insulation materials and in maximizing the increment in surface flashover voltage through electron beam irradiation-based surface modification. Additionally, the trend in surface resistivity aligns with that of the surface flashover voltage as irradiation energy increases. Furthermore, the beam irradiation changes the chemical bonds in epoxy composites, with -CH3 and -CH2 groups diminishing substantially and C-O and C=O groups incrementally prevailing as the irradiation energy increases. The C-O and C=O groups act as trap centers, increasing trap levels or densities, thereby impeding charge transport and enhancing the surface flashover property. However, the excessive trap density can distort the electric field stemming from severe charge aggregation, which leads to a gradual decline in surface flashover voltage.