关键词: 直流断路器, 仿真, 燃弧时间, 灭弧, 优化

Abstract: To address the challenges of insufficient ultimate breaking capacity and difficulty in extinguishing DC arcs in low-voltage small DC circuit breakers, research is conducted on optimizing the arc extinguishing performance of low-voltage small DC circuit breakers. A DC arc magnetohydrodynamic model is constructed by meshing the arc extinguishing system of a low-voltage small DC circuit breaker and coupling external circuit characteristics into it. By applying corresponding boundary conditions, the distribution of temperature, pressure and other parameters in the arc extinguishing chamber during the arc ignition process is successfully obtained. On this basis, the motion characteristics of the arc during the breaking process of low-voltage small DC circuit breakers are deeply explored, further revealing the inherent mechanism of the DC arc evolution process. A comprehensive arc extinguishing optimization method based on increasing circuit resistance, increasing constant arc extinguishing magnetic field, and adopting U-shaped double breakpoint contact structure is proposed. The simulation analysis results show that the optimization design method proposed in this paper can effectively elongate the arc column, raise the arc voltage, reduce the arc current and arc column temperature, effectively shorten the arc ignition time, and greatly improve the arc extinguishing ability and breaking performance of low-voltage small DC circuit breakers.

Key words: DC circuit breaker, simulation, arc ignition time, arc extinguishing, optimization