Characteristics of commutation failure based on fault recording

Commutation failure of the high-voltage direct current (HVDC) transmission system is common fault in a converter station. The fault recording in one converter station when commutation failure caused by the disturbance of the AC system was collected, and the turn-off angle of valves, zero-crossing offset, and landing amplitude of bus voltage were calculated and statistically analysed. The results suggested that, in the case of commutation failure, the turn-off angle of the 82% of cases was 90% cases, and the average was ∼4.6%. The number of cases, whose zero sequence voltage peaks was