Frequency Stability Analysis in Hybrid Power System Using Optimized Fractional Controller

Frequency oscillations in a unified power system remain a critical concern due to load uncertainties. These oscillations are mitigated through the use of controllers. In this work, a fractional mathematics-based Non-Integer Modified PID (NI-Mod-PID) controller is proposed to stabilize frequency oscillations in a hybrid power system integrated with an EV aggregator. The optimal gain parameters for the NI-Mod-PID controllers are determined using the Selfish Herd Optimization (SHO) technique to minimize frequency deviations. To simulate an imbalance between load and generation, a sudden load perturbation of 8% is introduced in the unified power system. The performance of the interconnected system, in terms of tie-line power and frequency oscillations, is assessed using response evaluation metrics such as positive peak, negative peak, and settling time. The superiority of the NI-Mod-PID controller is demonstrated by comparing its results with those of the conventional PID and NIPID controllers. In the later phase, the robustness of the proposed NI-Mod-PID controller is evaluated under unexpected load increases, further establishing its effectiveness and dominance in maintaining system stability.