A Frequency Regulation Strategy Based on Wind–Thermal Multi-Band Collaboration and Wind Turbine Energy-Constrained Control

The increasing integration of wind power reduces system inertia and weakens the frequency regulation capability of power systems. To address the problems of unclear task allocation, repeated compensation, and insufficient consideration of wind turbine energy limits in wind–thermal coordinated frequency regulation, this paper proposes a multi-band collaborative frequency regulation strategy with dynamic energy-constrained control. The proposed method decomposes the frequency deviation into high- and low-frequency components, enabling wind turbines to provide fast support and thermal units to undertake sustained regulation. A residual-based cross-band feedback mechanism is introduced to reduce repeated compensation, while dynamic segmented thresholds and releasable power constraints are used to adaptively adjust wind turbine support according to available energy. Simulations on a modified IEEE 3-machine 9-bus system show that, compared with the conventional strategy, the proposed method reduces the secondary frequency drop from 0.028 Hz to 0.015 Hz and shortens the recovery time from 20.7 s to 16.6 s. The results indicate that the proposed method can provide a practical reference for coordinated primary frequency regulation in wind–thermal power systems.