Fixed-Time ADRC for Enhanced Load Frequency Regulation of Interconnected Power System

With the rapid integration of renewable energy sources (RES), maintaining fast and stable load frequency control (LFC) in interconnected power systems has become increasingly challenging due to the uncertain nature of the system and the unreliability of RES. In contrast to existing asymptotic or finite-time stable active disturbance rejection control (ADRC) for the LFC problem, this paper proposes a novel fixed-time ADRC (FxT-ADRC) scheme for a two-area interconnected hybrid power system. The controller incorporates a newly developed extended state observer (ESO) capable of estimating system states and lumped disturbances within a fixed time frame, regardless of the initial conditions. This ensures timely state estimation and disturbance compensation, while rapidly stabilizing frequency deviations of the two-area system to zero. The convergence of the ESO and the stability of the system states are rigorously established using Lyapunov theory, ensuring fixed-time convergence of both disturbance estimation and state errors. To improve performance, the Magnetotactic Bacteria Optimization (MBO) algorithm is applied for optimal tuning of the ADRC gain parameters, while the proportional gain matrix is derived by solving a linear matrix inequality. Simulation studies demonstrate that the proposed FxT-ADRC achieves superior performance compared to existing asymptotic and finite-time ADRC schemes, providing faster frequency restoration, shorter settling time, and reduced overshoot and undershoot. Moreover, the method exhibits strong robustness against load variations and communication delays, and its effectiveness is further validated through real-time implementation on the OPAL-RT platform.