Time decomposition strategy for security‐constrained economic dispatch

Abstract

A horizontal time decomposition strategy to reduce the computation time of security-constrained economic dispatch (SCED) is presented in this study. The proposed decomposition strategy is fundamentally novel and is developed in this paper for the first time. The considered scheduling horizon is decomposed into multiple smaller sub-horizons. The concept of overlapping time intervals is introduced to model ramp constraints for the transition from one sub-horizon to another sub-horizon. A sub-horizon includes several internal intervals and one or two overlapping time intervals that interconnect consecutive sub-horizons. A local SCED is formulated for each sub-horizon with respect to internal and overlapping intervals’ variables/constraints. The overlapping intervals allow modelling intertemporal constraints between the consecutive sub-horizons in a distributed fashion. To coordinate the subproblems and find the optimal solution for the whole operation horizon distributedly, accelerated auxiliary problem principle is developed. Furthermore, the authors present an initialisation strategy to enhance the convergence performance of the coordination strategy. The proposed algorithm is applied to three large systems, and promising results are obtained.