Bridge-Type Hybrid DC Circuit Breaker With Multiple Ports for Multiterminal Flexible DC Grid

The hybrid DC circuit breaker is an ideal way to selectively and quickly isolate DC line faults in flexible DC grids. However, under the current technical conditions, the cost of hybrid DC circuit breakers is extremely high, and it is difficult to meet the large-scale demand for DC circuit breakers in multi-terminal flexible DC grids. To reduce the implementation costs of DC circuit breakers, a bridge-type hybrid DC circuit breaker with multiple ports is proposed in this paper. The proposed breaker can share the expensive main breaker among multiple adjacent lines to significantly reduce the total costs. Besides, a series branch of diode valve and resistor is configured to accelerate the fault interruption process. Extensive simulations are conducted to verify the effectiveness of the proposed bridge-type hybrid DC circuit breaker.