Improved Design of Fuse Tube for Environmental Protection Cabinet Based on Electric-Field Simulation

Abstract

Since the insulation performance of air is not as good as that of SF6 and other gases, it is necessary to conduct an in-depth study on the insulation characteristics of the fuse tube in order to meet the requirements of normal breaking and to design a structural improvement scheme for a 12 kV environmental protection cabinet fuse tube that is suitable for using air as the insulating medium. In this study, the insulation performance of the fuse tube before improvement was studied, and the electric-field distribution of the 12 kV fuse tube placed in the air-insulated switchgear was analyzed. The results showed that the electric-field was heavily concentrated in the air gap of the fuse tube plug and around the ground rod. In this study, the structure of the fuse tube was specifically designed. By spraying conductive paint on the intersection surface of different media, equipotentiality was achieved, and a reasonable metal shielding structure was added to the site where the field intensity was concentrated so as to improve the distribution of the electric-field and avoid the breakdown caused by the concentration of field intensity. Through several improved designs, the maximum electric-field strength of the fuse tube of an environmental protection cabinet can be effectively reduced, and the insulation requirements of relevant standards can be met. A partial discharge test for the improved fuse tube was carried out, and the local discharge quantity of the improved fuse tube met the industry requirements, which verified the rationality of the fuse-tube-improvement scheme.