The increasing complexity of modern power systems (MPSs), driven by the integration of renewable energy sources and multi-area configurations, demands robust and adaptive load frequency control (LFC) strategies. This paper proposes a novel approach to the LFC of the MPS by integrating a proportional–integral–derivative (PID) controller optimized using the gray wolf optimizer (GWO) algorithm. The effectiveness of the GWO-PID method is evaluated on multi-area power systems, including systems integrated with wind energy. The GWO-PID controller shows superior frequency stability, achieving deviations of 49.67 Hz, 49.68 Hz, 49.87 Hz, 49.87 Hz and 49.88 Hz for area 1 and area 2 of the two-area multisource MPS, as well as for area 1, area 2 and area 3 in the three-area multisource MPS. The results demonstrate significant improvements in frequency stabilization, reduced oscillations and enhanced steady-state accuracy compared to traditional optimization techniques. This study emphasizes the scalability and adaptability of the proposed method to changing load conditions and complexity of the MPSs, providing a potential solution to ensure stability and reliability for the MPSs.

This paper introduces a novel sliding mode control (SMC) design utilizing a Proportional-Integral-Derivative (PID) Sliding Surface (SS) for frequency regulation in multi-area electrical power systems (EPSs) with hydropower turbines, accounting for random load conditions, parameter variations, and matched uncertainties. The global system stability of this new approach is mathematically analyzed using Lyapunov theory alongside a novel Linear Matrix Inequality (LMI) technique. A robust strategy is employed through the reaching law method to ensure that frequency deviations converge to zero, even under varying load demands. Despite the presence of parameter variations and random load conditions, the control objectives remain achievable, highlighting the robustness of the proposed method. Moreover, this strategy results in lower overshoot, quicker response times, and reduced chattering effects compared to current traditional SMCs including Proportional-Integral (PI), double PI (DPI), and Proportional-Derivative (PD) sliding surfaces, demonstrating its advantages. Finally, the effectiveness of the suggested scheme is further verified based on three-area EPSs with matched uncertainties, indicating that the proposed scheme achieves stable and robust performance, further confirming its superiority through simulation results.