Research on Grid-Forming Flywheel Energy Storage-Supported Frequency Regulation Strategy for Renewable Energy Integration

As the penetration rate of renewable energy rapidly increases, power systems are facing challenges such as reduced inertia and weakened frequency stability. New energy units, represented by wind and solar power, are connected to the grid via power electronic devices. Their intermittent output and weak grid-support characteristics significantly weaken the system's dynamic response capability to power disturbances. Traditional grid-following (GFL) energy storage systems rely on phase-locked loops to track the grid phase, which faces limitations such as the risk of disconnection during faults and passive following behavior. To address this, this paper proposes a frequency regulation model based on networked flywheel energy storage, which simulates the inertia and damping characteristics of synchronous generators to provide active frequency support for high-renewable-energy-penetration systems. The study compares the frequency response differences between GFL and grid-forming (GFM) energy storage systems, establishes a system frequency response (SFR) model incorporating virtual synchronous generators (VSG) and droop control, and analyzes the dynamic characteristics under different load disturbances (0.1 p.u. and 0.5 p.u.). Simulation results show that GFM energy storage with VSG control, through virtual inertia and droop damping coefficients, can effectively suppress the rate of change of frequency (RoCoF) and steady-state deviation, outperforming traditional GFL energy storage. The optimization of droop control parameters (m) and VSG control parameters further verifies the potential of GFM energy storage in enhancing system frequency stability, providing a new solution for power systems with high renewable energy penetration.