With rapid growth of renewable energy sources (RESs) in modern power systems, the microgrids (µGs) have become more susceptible to the disturbances (e.g. large frequency/voltage fluctuations) than the conventional power systems due to decreasing their inertia constant. This low system inertia issue could affect the µGs stability and resiliency in the situation of uncertainties, thus threaten their dynamic security. Hence, preserving µG dynamic security is one of the important challenges, which is addressed in this study. Therefore, this study proposes a novel concept of frequency control incorporating a virtual inertia control-based optimal proportional-integral controller to emulate virtual inertia into the µG control loop, thus stabilising µG frequency during high penetration of RESs. Moreover, the proposed virtual inertia control system is coordinated with digital over/ under frequency protection for enhancement of the frequency stability and preservation of the µG dynamic security because of the high integration level of the RESs. The simulation results of the studied µG are carried out using MATLAB/Simulink ® software to validate the effectiveness of the proposed coordination scheme. Results approved that the proposed coordination scheme can effectively regulate the µG frequency and guarantee robust performance to preserve the dynamic security of µG with high penetration of RESs for different contingencies. Nomenclature velocity of particle i for n iteration c 1 , c 2 acceleration constant rand () Random number between 0 and 1

This study proposes a coordination of load frequency control (LFC) and superconducting magnetic energy storage (SMES) technology (i.e. auxiliary LFC) using a new optimal PID controller-based moth swarm algorithm (MSA) in Egyptian Power System (EPS) considering high wind power penetration (HWPP) (as a future planning of the EPS). This strategy is proposed for compensating the EPS frequency deviation, preventing the conventional generators from exceeding their power ratings during load disturbances, and mitigating the power fluctuations from wind power plants. To prove the effectiveness of the proposed coordinated control strategy, the EPS considering HWPP was tested by the MATLAB/SIMULINK simulation. The convention generation system of the EPS is decomposed into three dynamics subsystems; hydro, reheat and non-reheat power plants. Moreover, the physical constraints of the governors and turbines such as generation rate constraints of power plants and speed governor dead band (i.e. backlash) are taking into consideration. The results reveal the superior robustness of the proposed coordination against all scenarios of different load profiles, and system uncertainties in the EPS considering HWPP. Moreover, the results have been confirmed by comparing it with both; the optimal LFC with/without the effect of conventional SMES, which without modifying the input control signal. Nomenclature x i max upper limit x i min lower limit 2g/G social factor 1 − g/G cognitive factor best p best light source position ɛ 2 , ɛ 3 random numbers within the interval [0, 1] ɛ 1 random samples were drawn from Gaussian stochastic

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