Protection method and coordination with DC circuit breaker in DC distribution power grid

One of the constraints to further DC distribution system development is the lack of practical fast DC circuit breaker. In the paper, DC distribution system and breaker protection coordination is discussed. Feasible strategies and methods of protection coordination are proposed. At the same time, based on the actual system with different voltage levels and the circuit breaker prototype test results, the requirements on the parameters of the system and the breaker during the inter-poles fault transient process are calculated and simulated in PSCAD/EMTDC. The results show that there are different requirements on system withstand capability and breaker breaking performance with different protection strategies. And the appropriate protection strategies should be selected according to the system characteristics.