Deterministic Dynamic State Estimation-Based Optimal LFC for Interconnected Power Systems Using Unknown Input Observer

This paper proposes a novel, fully decentralized load frequency control (LFC) approach based on dynamic state estimation (DSE). The proposed approach employs an unknown input observer (UIO) for each power system area for tracking the dynamic states in real time operation. In order to achieve the fully decentralized control approach, the demand fluctuation and tie-line power deviations are modeled as unknown inputs to the UIO of each area. An optimal state feedback control method based on the observed states is used next to control each area separately. This approach reduces the complexity of the designed observer, achieves fully decentralized control, improves the robustness of the controllers, and makes the estimation process highly efficient, accurate, and easy to implement. The applicability of the proposed method is shown on a representative model of four areas interconnected via various transmission links. Simulation results demonstrate the efficiency and accuracy of the designed observer and verify the superiority and robustness of the proposed control approach compared to alternative approaches.