ZHANG Lei, ZHANG Guobao, YANG Wei, et al. DC Surface Flashover Characteristics of Epoxy Composites Modified by Ultraviolet Irradiation in Vacuum[J]. 2025, 51(5): 2494-2505.
DOI:
ZHANG Lei, ZHANG Guobao, YANG Wei, et al. DC Surface Flashover Characteristics of Epoxy Composites Modified by Ultraviolet Irradiation in Vacuum[J]. 2025, 51(5): 2494-2505.DOI: 10.13336/j.1003-6520.hve.20240759.
DC Surface Flashover Characteristics of Epoxy Composites Modified by Ultraviolet Irradiation in Vacuum
Surface flashover that occurs along the gas-solid surface of the basin-type insulators is one of the essential failures of GIS/GIL
which significantly threatens the safe operation of ultra-high voltage transmission systems. To enhance the DC surface flashover characteristics of basin-type insulators
epoxy composites are treated by ultraviolet irradiation in a vacuum
and various techniques
such as surface potential measurement and quantum chemical simulation
are adopted to obtain the distance of molecular chain
density
thermal stability
energy level band
trap parameters
surface charge distribution
and DC surface flashover voltage; moreover
the influence of ultraviolet irradiation on DC surface flashover is clarified. The results show that the DC surface flashover voltage of the 12-hour ultraviolet irradiated epoxy composites shows a 17% increment compared to the untreated sample. After surface hetero-charging for 6 h with a +20 kV voltage
the DC flashover voltage increases by 24%. The DC surface flashover is decreased by less than 2% six months after treatment
which exhibits long-term stability. The analysis of trap level and charge transport characteristics indicates that high-energy photons accelerate molecular chain crosslink after ultraviolet irradiation in a vacuum. The crosslinking structure facilitates the LUMO level of epoxy composites to decrease
thus large amounts of deep traps are introduced
which improves the energy level and density of epoxy composites. The increase of deep trap level causes charge to accumulate near the electrode
which impedes carrier injection from electrodes
therefore
the electric field above the solid surface is reduced
and the DC surface flashover voltage is increased. Based on the relationship among ultraviolet irradiation in a vacuum
charge transport
and surface flashover
ultraviolet irradiation in a vacuum can be an essential strategy in improving DC surface insulation of GIS in the future.