A virtual inertia assessment and frequency support technology for wind-storage power generation system

In high-penetration wind power generation systems， accurately assessing the support potential for virtual inertia of energy storage and fully releasing its energy reserves to render the systems active in grid frequency regulation are crucial for ensuring the systems’ frequency safety and stability. To achieve this， a dynamic frequency response model for wind-storage power generation systems to calculate the system’s time of safe frequency rise and fall and the extreme values of frequency deviation. Next， considering the constraints on the safe operating condition of the state of charge （SOC） during energy storage， the virtual inertia of energy storage during the time of safe frequency rise and fall is quantitatively evaluated. Moreover， an active frequency support technology for energy storage based on fixed-frequency control is introduced， aiming to fully exploit the frequency support capability of energy storage during the frequency drop and recovery periods. Finally， a simulation model of high-penetration wind power generation systems is constructed for validation. Under the proposed control strategy， energy storage can provide effective inertia support and offer sustained frequency response， thereby significantly enhancing the systems’ frequency stability.