Single-ended Protection Scheme of MMC-HVDC Transmission Line Based on Bridge Arm Inductor Voltage of Converter

Relay protection of transmission lines is one of the key issues facing the development of MMC-HVDC systems. This paper analyzes the fault equivalent circuit during the faults of the DC line in the different fault location in MMC-HVDC systems, and obtains the relationship between fault current components of upper and lower bridge arms, and analyzes differences of fault voltage components of both bridge arms inductors of converters on this basis. A protection scheme for MMC-HVDC transmission lines using the correlation coefficient of MMC upper and lower bridge arm inductors fault voltage components is proposed. The simulation results in PSACD show that the proposed scheme can effectively identify the fault location and has strong resistance to transition resistance.