Harris Hawks Optimization Assisted Fuzzy‐ <scp> PI ^λ </scp> Controller for Frequency Stabilization in Renewable Integrated Power Systems

ABSTRACT This paper presents an optimal design approach for tuning the scaling factors of a fuzzy fractional‐order proportional‐integral (Fuzzy‐PI λ ) controller using the Harris Hawk Optimization (HHO) algorithm, a modern and efficient metaheuristic technique. The controller is developed to regulate frequency in renewable‐integrated multi‐area power systems. Specifically, the method is validated on two‐area power systems, where Area‐1 integrates a grid‐connected photovoltaic (PV) system while Area‐2 comprises reheat thermal or hybrid reheat thermal‐geothermal generation units. The performance capability of the designed controller is shown against recent control strategies optimized using well‐known algorithms. To comprehensively evaluate performance, four standard performance index formulations are employed. The robustness of the controller is further tested under parameter uncertainties, solar irradiance variability, and load fluctuations. Additionally, eigenvalue‐based closed‐loop stability analysis has been performed to assess the system's stability under scenarios with high renewable energy penetration, highlighting the controller's proficiency in sustaining system stability. Simulation results consistently demonstrate the superior performance and robustness of the proposed HHO‐optimized Fuzzy‐PI λ controller under diverse operating scenarios.