Transient Stability Control for Grid-Forming Energy Storage Inverters Based on Torque Enhancement Strategy

Grid-forming energy storage inverter see transient power angle instability as traditional synchronous generator during disturbances. However, small-signal stability analysis theory is no longer applicable for grid-forming energy storage inverter facing large disturbances. This paper establishes a mathematical model for grid-forming energy storage inverter, then the Lyapunov direct method is employed to analyze transient attraction region for grid-forming energy storage inverter, and define impact relationship between the transient attraction region and virtual inertia influences, active power output level, and line parameters. Transient stability control for grid-forming energy storage inverters based on torque augmentation technique is suggested in light of stability theory research findings to increase the system's transient stability margin during faults. Lastly, the logic of the stability analysis approach is confirmed using MATLAB/Simulink simulations.