A novel solid-state protection scheme for DC system

The short-circuit fault will affect the continuity and reliability of the DC system seriously, so it must be detected and isolated quickly. DC circuit breaker can be used to break the system fault circuit more effectively. However, different from the AC system, the DC current has no natural zero crossing. If the mechanical circuit breaker is used for short circuit fault protection, it will bring an arc, which will require total time few milliseconds or even larger for complete interruption. As a result, the DC system voltage will drop during this period. In this paper, a new scheme will make use of impendence source to design a new type of DC circuit breaker: T-source DC solid-state breaker, which can break the short circuit fault more quickly so as to improve the continuity and power quality of the system. The main topological structure is presented and mathematical model is derived through comprehensive analysis. The simulation and laboratory results are shown to verify the theoretical analysis.