Estimating the domain of attraction for power systems via a group of damping-reflected energy functions

The well-known Lyapunov direct method provides precise and rigorous theoret ical backgrounds for stability analysis of nonlinear systems. However, inco rporating damping effects into accurate estimates of the domain of attracti on has proved difficult, which is pointed as a minor but crucial drawback. This paper presents a new method to derive a group of Lyapunov functions to reflect the damping effects by considering the first integral of motion ob tained from the system governing equations when transfer conductances are n eglected. A systematical approach of converting some part of damping loss i nto some appropriate system energy terms is developed. Examples show that t he proposed method remarkably improves the estimation of the region of attr action compared with the conventional approach. (C) 2000 Elsevier Science L td. All rights reserved.