Development of an optimized virtual inertia control strategy for frequency stability in a Two-Area Microgrid System

The increasing penetration of inverter-based renewable energy sources has significantly reduced inertia in modern microgrids, resulting to large frequency deviations. The conventional load frequency control methods are insufficient in such low inertia microgrids as they depend on the inherent inertia of the synchronous generators. This thesis presents the development of an optimized virtual inertia control strategy for frequency stability in a low inertia two-area microgrid system. A two-area microgrid system incorporating the diesel engine generators, wind turbines, photovoltaic systems and battery energy storage systems was modelled using the state-space mathematical model approach. The virtual inertia was emulated through the power electronic interfaces and controller parameters through fuzzy logic. The fuzzy-PID controller was evaluated under two distinct load disturbance scenarios using MATLAB/Simulink (R2024b). The simulation results demonstrate the optimized controller significantly reduces the frequency deviations, undershoot and overshoot amplitudes, and achieves faster settling time compared to conventional PID controller.