Simulation Analysis of the Motion Characteristics of Electromagnetic Repulsion Mechanism for 10kV DC Circuit Breaker

Flexible DC power grid is an effective way to solve the centralized grid connection and on-site consumption of new energy. The low inertia and weak damping characteristics of flexible DC power grid require DC circuit breakers to quickly cut off fault currents within 3ms. The electromagnetic repulsion mechanism is widely used in the operating mechanism of DC circuit breakers due to its high reliability and fast response speed. This article takes the electromagnetic repulsion mechanism as the research object. Firstly, the working principle of the electromagnetic repulsion mechanism is studied through theoretical analysis, the finite element simulation model is established based on mathematical models, six factors that affect the driving performance of the electromagnetic repulsion mechanism is analyzed, which including the capacitance value of the driving circuit, charging voltage, coil turns, repulsion disk materials, thickness and the initial gap between the coil and the repulsion disk. Based on simulation analysis, the inner diameter of the repulsive disk is 12.65mm, the outer diameter of the repulsive disk is 32.65mm, the thickness of the repulsive disk is 13mm, the number of coil turns is 19, the material of the repulsive disk is aluminum alloy, the capacitance value is 4mF, the charging voltage of the capacitor is 800V, and the initial gap between the coil and the repulsive disk is 2mm. An electromagnetic repulsion mechanism is designed, and a test platform is established, the opening distance of the mechanism reaches 6mm within 2ms, and the opening speed exceeds 3m/s, which meets the engineering requirements of DC circuit breakers and provides guidance for the design of electromagnetic repulsion mechanisms.