Stability Analysis of Large Scale Systems Composed of Strongly Coupled Similar Subsystems

Abstract A method for proving the stability of systems composed of subsystems with similar dynamics through symmetric interconnections is proposed which exploits the structural properties of such systems. The subsystems are described by a common approximate state space model and an individual upper bound of the modelling errors. For the stability of the symmetric core of the overall system a necessary and sufficient condition is given in terms of two matrices which have only the same order as the subsystems. For the stability of the overall system a sufficient condition is derived that can be successfully used even for systems with strong subsystem interactions and a large number of subsystems. This is demonstrated by proving the stability of a large multiarea power system, for which stability tests that are based on weak subsystem interactions fail.