Bipolar Hybrid DC Circuit Breaker with Surge Arresting Mechanisms on Source and Load Sides

With the deployment of DC power systems, DC circuit breakers are gaining attention in DC system protection as well as load and circuit operation. Different types of DC breakers are utilized and include static, mechanical, and hybrid DC breakers. Here, a hybrid DC breaker is proposed to harness the voltage rise due to the rapid current change during the current disruption in the line and load inductances at low and medium voltages. The bipolar hybrid circuit breaker is equipped with a surge arrestor and a freewheeling diode to harness the source and line/load inductances’ voltage rise, respectively. This will in turn restrict the switching voltage overshoots across the breaker contacts and help remove the arc quickly. The simulation and hardware test results verify that the method proposed can effectively interrupt fault currents with minimal arcing along with reducing erosion on the mechanical switch contactors.