The limiting and breaking technology of DC system short-circuit current is the bottleneck of DC transmission technology development.In view of this technical problem

this paper analyzes the existing DC current limiter and DC circuit breaker topology

and proposes a topology structure of an improved fault current limiter

which is suitable for DC systems.The principle of current transfer is used to break the circuit

so the rise rate and level of the short-circuit current can be quickly limited in the event of a short-circuit fault in the system

and the internal power electronic devices can be effectively protected from the damage caused by overvoltage.A simulation model is constructed on the Matlab/Simulink platform to simulate the fault current limitation.Simulation results show good current limiting effect of the proposed current limiter

and verify the function and current limit of the current limiter.