Impact of Wind Farm Integration into HVDC Receiving-end System on Commutation Failure

The integration of large-scale wind farms into HVDC receiving terminals has become an important application scenario. The impact of wind farms on HVDC commutation failure constitutes a critical issue for the safe and stable operation of the system. In this paper, we investigate the impact of wind farm connection to the HVDC receiving end system on commutation failure from two aspects: low-voltage ride-through control and phase-locked loop control of wind turbines. Firstly, a commutation area margin that accounts for the effects of voltage drop and harmonic distortion is developed, and a commutation failure identification method based on this commutation area margin is proposed. It is subsequently analyzed that low voltage ride-through control of wind power can enhance the voltage support capability, which is beneficial for improving the commutation failure process. It reveals that when the bandwidth of the phase-locked loop on the wind turbine grid side is large, the system may generate a larger second harmonic voltage, which will exacerbate the risk of HVDC commutation failure. Finally, the correctness of the proposed theory is validated through simulations on the PSCAD/EMTDC simulation platform.