Energy Storage Integrated Control Framework for Voltage and Frequency Regulation in Modern Grids

The increasing penetration of renewable energy sources has significantly reduced system inertia in modern power grids, leading to severe challenges in maintaining voltage and frequency stability. This paper proposes an energy storage–integrated control framework that enhances both frequency and voltage regulation in low-inertia, renewable-dominated grids. The framework combines virtual inertia control, virtual synchronous generator concepts, and an optimized supplementary controller tuned using the PID to dynamically coordinate active and reactive power support from a battery energy storage system (BESS). The proposed strategy enables fast emulation of inertia and damping characteristics, effectively mitigating frequency deviations, reducing the rate of change of frequency, and stabilizing voltage under transient disturbances. Detailed mathematical modeling of the grid, renewable sources, and control loops is presented to capture system dynamics accurately. Simulation results demonstrate that the BESS rapidly injects or absorbs power in response to load and generation variations, maintaining frequency close to nominal and limiting voltage excursions within acceptable bounds. Performance evaluation confirms a significant improvement in frequency nadir, RoCoF, settling time, and voltage recovery compared with conventional control approaches. The results validate the robustness, adaptability, and effectiveness of the proposed energy storage–integrated framework, highlighting its suitability for future microgrid grids with high renewable penetration and stringent stability requirements.