Abstract: Flexible DC power grid is an important way for efficient transmission of various types of renewable

energy. How to design an efficient reclosing strategy to make it have the ability of rapid recovery after fault is a key

problem to improve the stability of the whole AC/DC power grid. According to the working mechanism of DC circuit

breaker and converter，a reclosing control strategy and logic flow of circuit breaker & converter coordination was

proposed. In order to verify the proposed method，a three terminal 500 kV flexible power grid model and a DC

circuit breaker model were built in Matlab platform for simulation verification. In addition，a circuit breaker

experimental prototype of 8 switch groups was built，and the digital physical hybrid experiment with the flexible DC

power grid in Matlab was carried out to verify the feasibility and engineering applicability of the proposed reclosing

strategy.

      Key words: DC grid；DC circuit breaker；reclosing；control strategy；experimental prototype