The Influence of 12 kV Vacuum Interrupter Structure on Electric Field Distribution: A Simulation Study

In this paper, the influence of the voltage sharing shield, the main shield, and the contact distance on the electric field and potential distribution of the vacuum interrupter were studied by using COMSOL software.The results show that the field strength is concentrated at the end of the main shield, the end of moving and static contacts, and the area between main shield and contacts. These locations, where breakdown discharge occurs frequently, are key parts during the structural design of vacuum interrupter. By improving the structural symmetry of the vacuum interrupter, the uniformity of electric field distribution was enhanced. The maximum field strength was transferred from the vicinity of the contact to the end of the main shield by making the end of the main shield curling inward, which is good for arc extinguishing. The maximum field strength is minimized by setting the curling radius of the main shield end as 3 mm and the curling angle as 90°. The field strength near the contacts is minimized by setting the slope of the main shield as 15°. Setting the radius of the main shielding cover as 50 mm and setting the total length as 110 mm are more reasonable. By increasing the contact distance, the electric field intensity inside the vacuum interrupter was reduced, but the electric field distribution wasn't changed. The results of this paper could provide the theoretical basis for the miniaturization design of vacuum interrupter.