Analysis Of The Reasons For The Limited Performance Of Epoxy Resin Insulators In Dc Transmission Lines

high voltage standoff has a mature application base in AC systems and exhibits good electrical insulation characteristics in some high-voltage equipment. However, in the context of high-voltage direct current transmission, this type of insulating material is subject to special effects related to the characteristics of the direct current electric field.

The unidirectional nature of the HVDC electric field causes a large amount of charge to easily accumulate on the surface of high voltage standoff insulators. Unlike the periodic neutralization under AC electric field conditions, this charge accumulation continuously accumulates at the gas-solid interface. Charge accumulation alters the local electric field distribution, causing distortion of the electric field on the high voltage epoxy surface and edges. This distortion increases the tendency for surface discharge. If epoxy resin insulator is operated on DC transmission lines for a long time, surface flashover may occur, affecting the stability of insulation performance.