Overview of topology research on hybrid direct current circuit breakers

Continuous expansion in the scale of high-voltage flexible direct current (DC) transmission systems has resulted in higher requirements for clearing fault currents. The hybrid DC circuit breaker, as the most promising DC circuit breaker, can effectively isolate and remove the faults that occur in DC power grids. At present, hybrid DC circuit breakers can be divided into two types: two port and multiport. Two-port DC circuit breakers are used in a single line and have the advantages of simple and flexible control. Multiport DC circuit breakers are used at the DC bus and control the fault isolation operation of multiple lines connected to the bus. When compared to two-port DC circuit breakers, multiport DC circuit breakers significantly reduce the number of configurations, reduce costs, and occupy less space. First, this article classifies hybrid DC circuit breakers into two-port and multiport categories, and refines and organizes the two major categories. Then, it analyzes the functionality, reliability, control complexity, and economy of each scheme based on the topology structures proposed in the current literature. Finally, prospects for future research on hybrid DC circuit breakers are presented.