Supervisory predictive control of power system load frequency control

Objective: The objective of this paper is to develop a hierarchical two-level power system load frequency control. Design: At the button level, standard PI controllers are utilized to control area’s frequency and tie-line power interchanges. At the higher layer, model predictive control (MPC) is employed as a supervisory controller to determine the optimal set-point for the PI controllers in the lower layer. The proposed supervisory predictive controller computes the optimal set-points such that to coordinate decentralized local controllers. Blocking and coincidence point technology is employed to alleviate the computational effort of the MPC. In order to achieve the best closed loop performance, the MPC controller is designed to take generation rate constraint and non-minimum phase of thermal and hydro units into account. Main outcome measure: The effectiveness of the proposed scheme is verified through time-based simulations on a four-area power system and the responses are then compared with the PI controller and the centralized MPC. Conclusion(s): The results reveal that the proposed control scheme offers reliable and satisfactory control performance compared to the PI controller and centralized MPC. 2014 Elsevier Ltd. All rights reserved.