Mitigating Frequency Instability in Microgrids Using Virtual Inertia and Fopid Control

The increasing reliance on renewable energy sources (RES) has resulted in a reduced contribution from conventional generation units in the electrical grid, leading to a gradual decline in microgrid inertia. This reduction poses significant challenges to frequency stability within microgrid power systems. To address this issue, this paper introduces a virtual inertia rotor technique designed to effectively compensate for the loss of system inertia. The proposed method utilizes a Tilt-Integral-Derivative (TID) controller and a Fractional-Order Proportional-Integral-Derivative (FOPID) controller for load frequency control. However, due to the high penetration of RESs or sudden load fluctuations, the microgrid system frequency may experience unexpected deviations. To mitigate these risks, the proposed technique is integrated with a frequency protection relay scheme, ensuring the dynamic security of the microgrid, particularly under critical conditions. The effectiveness of this coordination is validated using MATLAB simulations under various load and generation imbalance scenarios.