Development of a Fast DC Switch Based on Electromagnetic Repulsion Mechanism

Abstract

This paper introduces the overall structure design of a high-speed, medium-voltage compact fast DC switchgear. This device is driven by an electromagnetic repulsion disc, and uses a bistable spring as a holding device to maintain the opening and closing state. We calculated the steady-state heating of the switch under rated current for a long time, the results show that the steady-state heat generation of the through-flow part can meets the requirements of relevant standards. Then we calculated the breaking field strength of the isolation fracture, the breaking capacity of the switch at the rated distance meets the requirements of the rated voltage. The electromagnetic repulsion force on the repulsive disk and the stress distribution of the kinematic structure show that, the operating mechanism of the device can meet the requirements of opening distance greater than 5 mm within 1 ms. The closing time of this switch is less than 5 ms, the material and mechanical properties can meet the requirements. The above analysis shows that this device can meet the needs of medium-voltage DC systems for compact and fast DC switches.