On the problem of reliable stabilization for large power systems

In this paper, we consider the problem of reliable stabilization for large power systems – when some of the controllers are faulty in the sense that they fail to act optimally, or do not function in the way that they were originally intended to function. Specifically, we introduce a solution concept that requires controllers to respond optimally (i.e., in the sense of mutual best-response correspondences) to the non-faulty controllers regardless of the identity or actions of the faulty controllers.At any time, we assume that the non-faulty controllers know only that there can be at most one faulty controller in the system, but they know neither the identity of the faulty controller nor how this faulty controller behaves. We present a design framework using an extended LMI technique for deriving reliable state-feedback gains; while a set of filters whose estimation-error dynamics satisfy certain quadratic integral constraints is used as decentralized observers within the subsystems for extending the result to the output-feedback case. Moreover, a sufficient condition for solvability of the problem is provided in terms of the minimum-phase condition of the subsystems. We also present an application of the results to a practical power system problem. Index Terms Decentralized control, extended LMI, filters, integral quadratic constraints, power system, reliable control, stabilization.