Research on commutation failure of Jinsu DC transmission project caused by a complex AC fault

Commutation failure is an important factor on safe and stable operation of the receiving-end power grid for high voltage direct current (HVDC) project. A commutation failure event in Jinsu DC transmission project caused by a complex AC failure was taken as background, process of fault and action sequences of protection was introduced, and the reason of the commutation failure and protection action was analysed from principle. Real-time digital simulation (RTDS) was connected to the true-type device of ultra-high voltage direct current (UHVDC) control and protection to form a closed-loop simulation platform. The commutation failure event was inversed, and the simulation result was compared with the actual recorded wave. The results show that abnormal AC voltage leads to the commutation failure.