An Online Structurally Constrained LQR Design for Damping Oscillations in Power System Networks

Abstract

This paper presents an online distributed control design for suppressing inter-area oscillations in large power systems under structural constraints posed on the underlying communication network. The presence of multiple clusters of generators in a power system results in several inter-area oscillation modes. By modal analysis we first show that the contribution of each inter-area mode on the electromechanical state response of the generators is heavily dependent on the perturbed initial state of the system. We then take advantage of this observation to design structural constraints on the communication graph. A parallelized constrained linear quadratic regulator (LQR) design is then proposed to balance the trade-off between performance and the level of sparsity induced in the network. Algorithms for practical implementation of the design are provided. Results are compared with the full order LQR and illustrated on the New England 39-bus power system model.