Mon, 05/12/2014 -
10:30 to 12:30
Salle des séminaires du L2S (C4.1)
Transient Stabilization of Power Systems: an Unified Approach Membres du jury: Christophe PRIEUR GIPSA-LAB Rapporteur José CAÑEDO CINVESTAV Rapporteur Romeo ORTEGA LSS Directeur de thèse Françoise LAMNABHI-LAGARRIGUE LSS Examinateur Jean-Claude VANNIER SUPELEC Examinateur Daniele CASAGRANDE Università degli Studi di Udine Examinateur Abdelkrim BENCHAIB ALSTOM Energie Examinateur Alejandro DONAIRE University of Newcastle Examinateur invité Abstract An electric power system (EPS) is a complex network of electrical components used to supply, transmit and use electric power. Its final goal is to provide reliable, secure and uninterrupted service to the end-user, this means, constant voltage and frequency at all time. Nowadays, the trend in electric power production is toward an interconnected network of transmission lines linking generators and loads into large integrated systems. Actually, a power system network is considered the most complex and bigger machine ever built by man since it can span an entire continent. For this reason, improving power system transient stability is of great significance in human society, since if the stability is lost, power collapse may occur in a large populated area and serious damages will be brought to a regional economy and the consumer's comforts. Therefore, considering all issues presented before, this research work tackles the transient stabilization of a multi-machine EPS subject to network disturbances from two approaches: centralization which considers no limitation in information exchange at any point of a given network, and on the other hand, decentralization which assumes the information exchange is not available. To this end, first we introduce a novel control theory to globally stabilize non-globally linearizable triangular systems employing a nonlinear dynamic state-feedback controller, which differs from standard backstepping since the strict-feedback form is no longer required. Then, based on these new ideas, the transient stabilization problem of EPS is solved from a centralized point of view ensuring, under some conditions on the physical parameters of the system, global asymptotic stability of the operating point. Subsequently, using only local measurements available with existing technology, the previous central controller is transformed into a truly decentralized one, provided that the derivative of the active power at each generator can be suitable estimated. Performance of both controllers is tested via numerical simulations considering several fault scenarios using the 10-machine New England benchmark. In contrast to the nonlinear solutions above, we offer an observer--based methodology for decentralized stabilization of large--scale linear time--invariant systems. The originality of this work relies on the fact that each local controller is provided with available local measurements, it implements a deterministic observer to reconstruct the state of the other subsystems and uses in a certainty--equivalent way these estimates in the control law. The observers are designed following the principles of immersion and invariance. Furthermore, the class of systems to which the design is applicable is identified via a linear matrix inequality solution, from which the observer gains are obtained. Keywords: Electric power systems, decentralized nonlinear and linear stabilization, linear matrix inequalities, immersion and invariance, observer and adaptive control.