Two time scale decomposition and stability analysis of power systems

In this paper we consider the stability analysis of power systems by decomposition. Our approach employs the time scale property and its use in the decomposition of the large scale system into slowly coherent areas. For a composite system in the Lur¿¿ form, we show that the slow coherency transformation results in slow and fast subsystems which are also in the Lur¿¿ form. A weighted sum scalar Lyapunov function is formed from the slow and the fast subsystems, and stability properties of the composite system are analysed. A numerical example is presented to illustrate the method.