各向异性体电导率下环氧胶浸纸套管气固界面电荷积聚过程仿真

The valve-side bushing of UHV converter transformer is the throat of DC transmission system, and its reliability is crucial for the safe operation of the DC transmission system. In this paper, the ±800 kV converter transformer valve-side bushing is studied on the basis of the measured anisotropic body conductivity of epoxy-impregnated paper. Moreover, the influence of bushing core temperature gradient on the conductivity of epoxy- impregnated paper under actual working conditions is taken into consideration, and an electric-thermal-flow coupling simulation analysis model of DC bushing is established. The transient process of charge accumulation and electric field change of the bushing is analyzed. It is found that, after considering the anisotropic body conductivity, at the voltage of +800 kV, most of the outer surface of the epoxy core at the SF6 end of the bushing accumulates positive charge, and there is a maximum positive charge density of 24.66 pC/mm² near the outer inflection point of the arc corner surface. There is a large amount of negative charge accumulation on the gap surface and the arc corner surface near the shielding cover, and the maximum negative charge density is −14.82 pC/mm². There is a maximum positive/negative charge density in a small local area. Under the action of accumulated charge, the field strength between the epoxy core at the bushing end and the shielding cover increases, which increases the risk of surface flashover of bushing caused by gap discharge.