Load Frequency Control for Multi-area Power Systems: A State-Separation-Based Reconstructed Model Approach

This paper analyzes the load frequency control (LFC) problem for power systems based on sampled-data control. Different from the conventional LFC system model, a novel reconstructed LFC system model is proposed by separating the sampled-data-related state variables from those unrelated to the sampling measurements. In contrast to existing Lyapunov-Krasovskii functionals (LKFs) constructed using full state variables, this paper proposes an innovative reduced-order LKF that reduces the number of introduced decision variables by primarily relying on the sampled-data-related state variables of the system. Based on the proposed reconstructed LFC model and the proposed reduced-order LKF, stability criteria with fewer decision variables can be obtained. Simulation results show that the stability criterion derived from the reconstructed LFC model significantly reduces computational complexity while maintaining a reasonable level of conservativeness.