Research on Optimal Design and Application of Critical Load Current for Bidirectional Non?polar DC Circuit Breaker

Arc stagnation under critical load current is a key problem restricting the breaking performance of bidirectional non-polar DC circuit breakers. Based on the Elenbaas-Heller arc energy balance model, this paper proposes a bidirectional magnetic field enhancement method using a combined structure of symmetrical permanent magnets and magnetic conduction plates. This method optimizes the magnetic circuit through the layout of opposing permanent magnets coupled by a magnetic circuit, resulting in an increase of over 86 times in the longitudinal magnetic field strength within the contact region, thereby significantly enhancing the arc driving capability. This research provides an effective technical pathway for the application of highly reliable and compact DC circuit breakers in scenarios such as photovoltaic energy storage and distributed DC microgrids.