Optimized cascaded regulation strategy for robust automatic generation control in renewable-integrated power networks

Ensuring stability of both voltage and frequency in linked power networks (LPNs) is a critical challenge, primarily due to their nonlinear dynamics and load variability. Due to the high penetration of intermittent renewable energy sources, traditional Load Frequency Control (LFC) and Automatic Voltage Regulation (AVR) schemes often struggle to ensure fast, robust, and coordinated regulation in modern multi-area hybrid grids. To address these limitations, this research introduces a novel cascaded control architecture developed for Load Frequency Control (LFC) and Automatic Voltage Regulation (AVR) within a three-area hybrid LPN comprising thermal, wind, hydro, photovoltaic, and diesel generation sources. The proposed framework integrates three cascaded regulators: FOPI, TIDμ, and PIDA. Combining strengths of the three controllers provides better transient response, higher robustness against system uncertainties, and Improved steady-state accuracy. Also, for better performance, the parameters of the proposed controller are optimally selected using a recent developed optimization algorithm called Differential Creative Search (DCS). All simulations were carried out in MATLAB/Simulink environment. The obtained results are comprehensively compared to results obtained by utilizing other algorithms, Artificial Ecosystem-based Optimization (AEO), Dandelion Optimizer (DO), and the Runge-Kutta Optimization (RUN) algorithm. Results indicate that the DCS algorithm achieved the superior outcome, attaining the lowest objective function value of 0.0507, surpassing AEO, DO, and RUN with values of 0.0706, 0.0789, and 0.0649, respectively. Furthermore, the proposed controller was benchmarked against advanced control strategies such as FOPI-PI, TFOIDFF, and FOPI-PIDD2, yielding improvements in objective function values by 28.89%, 54.89%, and 26.42%, respectively. The simulation findings demonstrate that the FOPI-TIDμ-PIDA controller ensures significantly reduced overshoot by less than 0.12 Hz, faster settling times by less than 9.4 s, and enhanced voltage-frequency regulation even under ±25% variations in system parameters. Collectively, these results Proves the robustness, adaptability, and effectiveness of the proposed controller in advancing the stability and resilience of sustainable hybrid linked power networks.