Transient Frequency Coordinated Control Strategy for Wind Farm Augmented with Energy Storage

To enhance the frequency response of wind energy storage system after a short-circuit fault, a coordinated control strategy is proposed. Initially, the impact of wind storage power on the rate of frequency change during the frequency rise phase and the frequency extremum during the recovery phase is analyzed. Based on the analysis, a variable weight coefficient related to the severity of frequency disturbances is introduced to develop an optimization model for determining the reference power of wind storage. Subsequently, the frequency regulation capability of the wind turbine during fault ride-through and steady state operation is assessed. The reference power for wind power generation is derived by considering rotor energy balance. The value is then compared with the reference power of wind energy storage to determine the required reference power. Finally, simulations are conducted on a four-machine two-area system and an actual system in a specific region. The results demonstrate that the proposed control strategy effectively reduces the frequency fluctuation range and accelerates frequency recovery. Additionally, the control strategy can optimize the frequency modulation capability of wind power generation and avoid the issue of secondary frequency drops.