Frequency safety demand and coordinated control strategy for power system with wind power and energy storage

According to the constraints of frequency safety indices, evaluating the inertia and primary frequency regulation demand, rationally utilizing the energy reserve provided by wind turbines and energy storage devices to ensure the safety of the system frequency response, is the key to improve the stability of large-scale new energy power systems. First, frequency response characteristics and frequency regulation safety indicators required by new energy generation systems were analyzed. Second, the frequency dynamic response model of the system with wind power and energy storage was established, and the extreme value time for the virtual inertia response of the system was calculated. Using the extreme time at which the frequency drop is maximum, the virtual inertia time constant of the wind-storage system was evaluated. Additionally, the system inertia and the primary frequency regulation demand were obtained considering the frequency safety indices, and a novel coordinated control strategy for wind power and energy storage to provide the required frequency support was proposed. Finally, a grid-connected wind-storage simulation system was built to verify the superiority of the proposed control strategy. The obtained results indicate that the proposed control scheme flexibly meets the system frequency safety requirements.