Abstract: The increasing penetration of renewable energy is reducing the role of traditional synchronous machines and introducing new stability challenges in modern power systems. Inverter-based resources enable renewable integration but lack natural inertia and strong reactive power capability, leading to frequency instability, weak voltage regulation, and higher sensitivity to disturbances. This study investigates how combining battery energy storage systems with VSC-HVDC transmission can enhance grid stability. Two MATLAB/Simulink models are developed: a grid-connected PV system with BESS and a multi-terminal VSC-HVDC system integrating offshore wind power. Both systems are tested under grid faults and load disturbances using grid-forming and grid-following control strategies. Results show that grid-forming converters outperform grid-following ones in inertia emulation, frequency response, and fault ride-through capability. Coordinated BESS–HVDC operation improves transient stability, dynamic voltage support, and reliable renewable power transfer. The findings align with IEEE 2800-2022, demonstrating advanced coordinated control of storage.

Keywords: Grid stability, Inverter-Based Resources (IBRs), VSC-HVDC, BESS, converters, frequency support, voltage regulation

Pages: 440-455