Miniaturization design of closing electromagnet for fast contact mechanism of DC circuit breaker in power grid

Abstract

The newly designed DC circuit breaker closing electromagnet must meet the requirements of small size and fast action. This article focuses on the design index of the electromagnet, and carries on the preliminary design based on the empirical formula. On this basis, with the smallest volume as the objective function, a steady-state simulation design is carried out using BOBYQA's optimization algorithm. The design results are input into the transient simulation model to solve and analyze the characteristic changes of the solenoid coil voltage and current. Simulation and prototype test results show that under AC220V 50Hz full-wave rectification excitation, the moving iron core starts to move in 18.8ms and completes a 6mm stroke in 30.8ms; the peak coil current during the continuous flow is 4.15A, which meets the design index requirements of the electromagnet. The new scheme provides a reference for the design of DC circuit breaker closing device.