الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Power systems have recently faced significant challenges due to the increased penetration of renewable energy sources (RESs) such as frequency deviation due to fluctuations, unpredictable nature, and uncertainty of this RES. There are many reasons behind the high penetration of the RESs such as the lack of fossil fuels resources, reducing the carbon dioxide emissions, and extending the capacity of the existing power system networks. Hence, the penetration of the RES into the power system networs is introduced as a feasible solution to these challenges and is proressivelly rising in both providers and consumers sides, knowing as distributed generation (DG). The connection of these DGs to the distribution networks has created a hybrid power system known as Microgrid. Microgrid (MG) is a feasible approach in this direction to support the integration of sustainable power sources with conventional sources to reduce dependency on traditional energy entirely. An MG is composed of small generation and load units that are positioned in various locations in the network. A MG operates with the medium voltage (MV) distribution system in the integration mode or in the isolation mode. As load fluctuates over time, generated power must be automatically updated to meet the demand. This configuration is known as automatic load frequency control (LFC). Thus, LFC provides frequency balancing by regulating the prime mover speed, as well as tie-line power flow stability during normal and disturbed conditions. In this thesis, a cascaded controller named (1+PD)-PID controller is proposed to reduce the impact of RES uncertainties on the system and maintain the system reliability during fluctuations. The proposed controller is a combination of (1+PD) and PID controllers in order. The output of the (1+PD) controller is used, besides the deviation in frequency and power difference between nearby areas, as input to the PID controller to create the load reference signal. The parameters of the controller are optimally tuned using African vulture optimization algorithm (AVOA) to ensure the best performance of the controller. Two-area interconnected system with non-reheat thermal power units combined with RES such as solar and wind energy are modeled using MATLAB/Simulink to evaluate the system performance. The performance of the chosen optimization algorithm (AVOA) is compared with the performance of other optimization techniques such as Ant Lion Optimizer (ALO), Genetic Algorithm (GA), Grasshopper Optimization Algorithm (GOA), Harris hawks optimization (HHO). AVOA provides the best performance between these techniques with the least fitness function. The controller effectiveness and robustness are verified by subjecting the studied system to various types of fluctuations such as step load disturbance, variable load perturbation and RES penetration. In each case the performance of the proposed controller tuned by the AVOA is compared with the performance of other controllers tuned with the same optimization technique such as the conventional proportional integral derevitive (PID) controller, fractional order-PID (FOPID) controller and tilt integral derivative (TID) controller. The obtained simulation results prove that the proposed (1+PD)-PID controller in the integration with AVOA offers a considerable improvement in the system performance specifications. Moreover, they also prove its superiority over other comparable controllers having the least fitness function.