Current Suppression Method for DC Side Short Circuit Fault of MMC

A DC fault current limitation method based on partial bypass of sub-modules is proposed in this paper. For VSC-HVDC, the development mechanism of fault is analyzed. Considering the influence of component parameters and DC outlet voltage on fault current rising rate, the voltage modulation strategy of converter bridge arm during fault period is designed to suppress the fault current. Finally, a two-terminal flexible HVDC transmission system is built on MATLAB/Simulink to simulate and analyze the circuit fault, and the fault current is reduced from 13.15 kA to 10.12 kA at 6 ms by the proposed method after the fault.