Electric Field Analysis and Shielding Optimization of 15kV DC Switchgear Wall Bushing

Abstract

Aiming at the 15kV direct current (DC) switchgear busbar wall bushing is prone to local aging resulting in insufficient insulation capacity.In this paper, according to the response surface parameter optimisation method, Maxwell-Workbench joint simulation is established to carry out numerical calculations of electric field on the parameterised model of shielding ring of wall bushing, and to study the influence of the structural parameters of the shielding ring on the distribution of electric field and the optimal combination of structural parameters of the shielding ring. The results show that the maximum electric field intensity without the shielding ring appears at the position of the connection between the fixing plate and the wall bushing and at the position where the inside diameter of the casing is closest to the busbar.The high potential shielding ring mainly affects the electric field strength of the air region inside the wall bushing, and the ground potential shielding ring mainly affects the electric field strength of the air region outside the wall bushing;The ground potential shielding ring should be as far as possible beyond the location where the fixing plate is connected to the wall bushing;The high ground potential shielding ring is closer, the electric field between the shielding rings is drum-shaped, and the electric field strength inside the casing is higher;The high ground voltage shielding ring is farther away, the electric field is funnel-shaped, and the electric field intensity is small at the connection position between the wall bushing and the fixing plate, which is favourable to the insulation life of the wall bushing and the partial discharge;Analysing and obtaining 4 groups of shielding ring structure parameter combinations that meet the insulation requirements can effectively improve the electric field distribution and reduce the electric field intensity.