Commutation Failure Analysis in Multi-Infeed HVDC Systems

The commutation failure vulnerability of multi-infeed HVDC converters to ac side faults is analyzed. Faults in multi-infeed systems can cause commutation failure events in the nearby local converter or concurrently in both converters. The immunity of the system to both these events is investigated and suitably parameterized. “Commutation Failure Immunity Index” is calculated for multi-infeed systems with different ratings. Anomalous failure in valve current commutation due to voltage distortion has been investigated.