Scalability Study of Modular Hybrid DC Circuit Breaker with Embedded Auxiliary Power Supply

DC circuit breakers (DCCBs) play a crucial role in the development of future DC distribution grids. The hybrid dc circuit breaker (HCB) which boasts both low conduction losses from mechanical switch and fast turn-off speed from solid-state switch presents as a desirable option for medium-voltage direct-current (MVDC) distribution systems. In order to reach higher voltages, modular approaches have been investigated for the solid-state branch. However, overall HCB level scalability deserves more investigation and is discussed in this paper. Such scalability analysis could simplify the design for the series connected HCBs. Moreover, an embedded auxiliary power supply structure is proposed to ease the challenge of higher insulation requirement.