This paper presents a digital model of decentralized Load Frequency Control (LFC) using an optimal PID controller-based Particle Swarm Optimization (PSO) in Egyptian Power System (EPS) considering communication delays. The EPS includes both conventional generation units (i.e., non-reheat, reheat, and hydraulic power plants) with inherent non-linearities and wind power, which extracted from Zafarana wind farm, location in Egypt. Thus, the optimal digital controller-based Tustin’s technique is designed for every subsystem of the EPS separately to guarantee the stability of the overall closed-loop system. The performance of the proposed digital model is tested and compared with the analog model under variation in loading patterns, loading conditions, system parameters, wind farm penetration, and communication delays. Results approved that, the proposed digital model can effectively regulate the system frequency and guarantee robust performance under different conditions. Also, it gives a reliable performance at large sampling times, which means a reduction of implementation cost.