Hybrid HVDC converter with fault current limiting capability

This paper proposes a hybrid HVDC converter with fault current limiting copiability for the offshore wind power DC transmission system. By combining a diode rectifier and an auxiliary converter, the hybrid converter realizes low-cost and high-reliability power conversion. The auxiliary converter is also able to output negative voltage for current suppression during faults. By eliminating expensive DCCBs, the construction cost of offshore wind power is reduced. The analysis of topology and the operation modes of the hybrid converter are carried out. The fault current equations are deduced to reveal the fault current limiting principle. The fault protection strategy of the hybrid converter as well as high-speed switches are proposed. The verification of the feasibility of the hybrid HVDC converter with fault current limiting capability is conducted by simulations on MATLAB/Simulink.