The Analysis of Influence of HVDC Commutation Failure on Current Differential Protection

The commutation failure is one of the most common faults in HVDC transmission systems. After the commutation failure, the distortion of the fault characteristics has an impact on the current differential protection, which may cause the braking amount in the fault zone to be greater than the action amount, causing the protection rejection. In this paper, a HVDC transmission model is built based on PSCAD/EMTDC as a simulation tool. Simulation verification shows that when high-resistance grounding occurs in the transmission line near the DC inverter station, commutation failure of the inverter side may cause current differential protection rejection. High resistance grounding occurs in the remote area of the inverter station. The DC does not commutation failure. The current differential protection can operate correctly.