Response Mechanism of DFIG to Transient Voltage Disturbance Under Commutation Failure of LCC-HVDC System

Commutation failure is one of the common faults in the line commutated converter high voltage direct current (LCC-HVDC) transmission system, which will lead to a transient voltage disturbance with the characteristic of "decrease first and then increase" at the feed end. Such a transient voltage may cause severe dynamic responses on the wind generator adjacent to the converter station, resulting in the tripping of large-scale wind turbines and even cascading failure. By analyzing the principle of the transient voltage, this paper investigates the response mechanism of doubly-fed induction generator (DFIG), involving the variation of electrical parameters and fault ride through (FRT) ability. Further verifications through simulations and experiments prove that under the disturbance of commutation failure, DFIG may suffer greater transient shocks compared to a single sag or swell disturbance event. Finally, some suggestions are put forward to mitigate the transient voltage and improve the transient response of DFIG.