Dynamics-aware Continuous-time Economic Dispatch: A Solution for Optimal Frequency Regulation

Abstract

This paper outlines a continuous-time economic dispatch (CTED) problem that intrinsically embeds dynamic constraints arising from the electromechanical behavior of synchronous generators and enables near-to-real-time optimal scheduling of generation. In its original form, the CTED problem is infinite-dimensional, however, we present a linear-programming reformulation that offers computational burden comparable to traditional economic dispatch. The resulting optimal dispatch trajectories are continuously differentiable and induce only small-signal variations in automatic generation control signals. In addition to yielding better system frequency response, this improves economic efficiency since the dispatch cost is better aligned with the actual cost of operating the system. We demonstrate the economic advantages and dynamic-performance improvements of the proposed method with time-domain simulations for a detailed differential algebraic equation model of an illustrative power network.