Abstract: The integration of battery energy storage can prevent the secondary frequency drop during wind power frequency regulation, aiding in the improvement of wind turbine's frequency regulation performance. However, the exit of energy storage may also pose a risk to frequency recovery. To mitigate the secondary frequency drop caused by battery energy storage exit during wind-storage integrated primary frequency regulation. Firstly, the mechanism of frequency drop caused by the exit of energy storage in wind-storage joint frequency regulation is elaborated, and a control method for energy storage withdrawal based on Newton's cooling law is proposed. Then, based on this, a joint frequency regulation strategy for wind-storage systems is introduced, utilizing the complementary characteristics of wind power and energy storage to achieve smooth energy storage exit and collaborative frequency regulation. Finally, a simulation model incorporating high-penetration wind turbines was developed. The simulation results demonstrate that the active power sudden drop during the energy storage disengagement process transitions from a non-zero value to zero under this strategy, which validates the effectiveness of the proposed control method.

Key words: frequency response, wind power, energy storage, frequency secondary drop