Coordinated self-tuning frequency support control strategy for wind turbine and energy storage battery against time-varying operating conditions

Constrained by the rotor speed limit of Wind Turbines (WTs), high wind power penetration grids present the phenomenon of secondary drop in frequency regulation, and the steady-state deviation is rather significant. While Energy Storage Batteries (ESB) installed in wind farms can provide long-term frequency regulation services, the coordination mechanisms between ESB and WTs remain underexplored. This paper investigates the root cause of secondary frequency drop induced by insufficient rotor kinetic energy reserves. By analyzing the propagation of frequency disturbance signals through WT and ESB control loops, a coordinated control framework integrating DC-link ESB with WTs is developed to mitigate secondary frequency drop from an energy-balance perspective. Furthermore, to address the critical need for matching source-side support capabilities with system frequency regulation demands under time-varying operating conditions, this paper proposes a self-tuning droop-inertia parameter control method. This method dynamically adapts to operating conditions, thereby enhancing the coordinated frequency regulation capacity of WTs and ESB across diverse source-side states. Simulation results indicate that the proposed method enhances the frequency nadir, alleviating the secondary frequency drop and contributing to the secure operation of the system. • Investigate the synergistic relationship between WT and ESB during disturbance process. • Configure storage energy on the DC side to alleviate the secondary frequency drop problem. • A quantification method for complex operating conditions is proposed. • Adaptive converter parameters achieve incremental power allocation. • Frequency modulation unit support capability matches system regulation demands.