الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Load frequency control (LFC) has been widely recognized as a feasible tool in power system frequency regulation. With the rapidly increasing scale of power grids and proportion of renewable in power systems, the frequency control has been potentially impaired because this occurrence may raise more power fluctuations and diminish power system inertia. In light of this, there is a necessity to accommodate the current frequency control methods to the emerging integrated power systems. Against this background, this thesis addresses the frequency control problems from two aspects: one of ameliorating the performance of load frequency control immediately after frequency excursions, and the other of mitigating the power fluctuations in renewable energy sources penetrated power systems. On the one hand, the traditional frequency control can be enhanced by tuning appropriate parameters through optimization tools.Therefore, this thesis proposes two novel controllers tuned by new metaheuristic optimization techniques. For the first case study, a cascaded Proportional Integral-Fractional order Proportional-Integral-Derivative (PI-FOPID) controller tuned by the gorilla troops optimizer (GTO). In addition, a new combined Fuzzy Fractional-order Proportional-Integral (FOPI) and Tilt-Integral-Derivative (TID) controller tuned by the wild horse optimizer (WHO) has been proposed for the second case study. The first case study is a two-area microgrid system that contains diesel generators, various renewable energy sources such as photovoltaic (PV) and wind generation systems, as well as different energy storage devices. The second case study system is a two-area conventional power system integrated with different RES including photovoltaic and wind generation as well as distributed electric vehicles (EVs) between the two areas. The effectiveness of the proposed controllers is tested under various scenarios including step load perturbation, random load variation, wind speed fluctuation, solar irradiance change and sensitivity analysis. The disturbance of wave energy oscillation is applied in Area 2 in the second case study to evaluate the robustness of the proposed controller. The performance of the proposed cascaded PI-FOPID controller is compared to the single structure fractional order PID (FOPID) controller based on GTO and numerous other optimization techniques presented in the previous literature such as Genetic Algorithm and Particle Swarm Optimization. In addition, the proposed Fuzzy FOPI+TID controller is compared with the conventional PID, single TID, and individual Fuzzy FOPI controllers using the proposed WHO algorithm and other optimization algorithms presented in the previous literature. The results show that the proposed controllers are superior to other controllers in terms of peak overshoot, maximum undershoot and settling time for all scenarios. Unfortunately, the combination of various controllers in the proposed controllers increase their complexity as well as their cost. Furthermore, the presence of EVs helps in improving the frequency and tie-line power deviations. The simulation results are carried out using MATLAB/SIMULINK.