Frequency regulation strategy of wind storage hybrid system based on effective inertia margin

• .Estimates effective inertia of wind turbines across operating conditions and wind speed ranges. • Proposes effective inertia margin concept and allocates unbalanced power based on it. • Proposes and validates a two-layer frequency regulation strategy for wind-storage system. As the renewable energy penetration grows, wind turbines are increasingly involved in the frequency regulation of the power system. Due to the spatial and temporal uncertainty of regional wind speeds, the active power support capacity of each wind turbine in large wind power generation fields varies. The effective inertia of wind turbines is an important parameter in the high-proportion renewable energy penetrated power system. It can help the power system suppress frequency fluctuations and maintain system stability. The frequency regulation capability of wind turbines can be estimated through rotor speed analysis. Therefore, the frequency regulation strategy for the wind-storage hybrid system based on effective inertia margin is proposed. Based on the historical data of the wind power plant, wind speed prediction is conducted using the TPA-LSTM algorithm. The effective inertia of wind turbines in different wind speed intervals is estimated. The frequency regulation power distribution among turbines is balanced based on the effective inertia margin of turbine and the capacity of converters. The frequency regulation parameters of the turbines and the power variation of battery energy storage are optimized by Model Predictive Control. The effectiveness of the proposed control strategy is verified through simulation cases using practical wind farm data. The simulation result reveal that the active power support capability of wind turbines at low wind speeds is more effectively utilized, thereby enhancing the frequency response capability of large-scale wind farms.