Analysis of commutation failure faults in HVDC transmission systems

High-voltage direct current (HVDC) transmission systems can transmit power over longer distances and with higher capacity, making them a crucial transmission method in the future. However, when commutation failure occurs in an HVDC system, it can cause DC current surges and temporary power interruptions, severely threatening the safe and stable operation of AC/DC hybrid systems. Therefore, this paper focuses on commutation failure faults in HVDC transmission systems, analyzing the causes of commutation failure. It also examines the protection criteria, protection blocking conditions, and protection action outcomes for commutation failure. Finally, by analyzing the actual fault waveforms from a converter station, the control and protection systems are studied to determine the root cause of the commutation failure.