A Novel Hybrid Solid State Circuit Breaker for DC System

With advancement in the solar PV based generations, DC micro grid has evolved, and it is beneficial over the conventional AC grid due to less loss and easier to control. However, fault detection and breaking during faults is a challenging task, due to unavailability of zero crossing. Hence, to enhance the application of the DC supplies, solid state breakers are developed and have promising results in small scale uses: such as, battery storage, ship yard, microgrid etc. Further, with increase in fault current in high power applications, fast acting circuit breaker with the use of solid state switches termed as a hybrid breaker to limit the current stress. However, the available hybrid breakers in literature are complex and difficult to realize for higher power levels. In this work, a novel hybrid breaker is proposed which uses the voltage across capacitor to turn off the solid state breaker (SSB) after the operation of the fast-acting switch. The simplicity of this topology is an advantage for application of the breaker in DC micro grid. Simulation results on a 400 V, 72 kW DC system in MATLAB/SIMULINK shows the proposed technique is able to break the circuit within 5 ms.