Abstract
This paper introduces the principle, operation and topology family of the novel T-type Modular Dc Circuit Breaker (T-Breaker) system for future dc networks. The T-Breaker system has a modular structure, locally integrated energy storage, high tolerance to control signal mismatch during the fast network transients, and capability to assist power flow control, power quality improvement and stability enhancement. This is a paradigm shift from traditional solid-state circuit breakers (SSCBs) as the proposed T-Type Breaker not only protects against faults, but also can eventually function as an energy router with unparalleled ancillary functions for dc grids.