ABSTRACT With the increasing participation of wind turbines (WTs) in reactive power regulation, voltage stability can be improved. However, such involvement significantly increases the fatigue load on the low‐speed shaft (LSS). Since the fatigue load of WTs varies dynamically with the degree of reactive power support, this paper proposes a hierarchical response control (HRC) method for voltage support in doubly fed induction generators (DFIGs) that considers fatigue load. First, the power requirements of WTs under different grid voltage conditions are clarified. Second, a fatigue load sensitivity model is established to reveal the coupling mechanism between reactive power support and torque fluctuations in the drivetrain. Finally, with reactive power support capability and minimised fatigue load as optimisation objectives, and considering load fluctuation factors, filter parameters are adjusted in real time to avoid the inherent oscillation frequency of the shaft system, and the voltage regulation power is reasonably allocated among the units. Experimental results based on a 10 MW DFIG show that the proposed HRC method ensures reactive power support during grid voltage faults while effectively reducing the fatigue load on the drivetrain and tower. Specifically, under a voltage dip to 0.2 p.u., the proposed strategy reduces the torque fluctuation of the LSS by 3.36% and the fluctuation of the fore–aft bending moment at the tower base by 35.48%; under a voltage swell to 1.25 p.u., the load fluctuation of the LSS is decreased by 23.46% and the mean value of the tower‐base fore–aft bending moment is lowered by 31.79%; under a cascading fault (0.2–1.25 p.u.), the standard deviation of the tower‐base side–side bending moment is reduced by 42.19%. Furthermore, rainflow counting and the Miner linear cumulative damage rule reveal that the equivalent fatigue load of the LSS is reduced by 7.04%, 28.61%, and 10.65% under the voltage dip, voltage swell, and cascaded fault conditions, respectively.
Yang et al. (2026) studied this question.