Transient Stability Analysis of Multimachine Power System with Field Flux Decays via Lyapunov´s Direct Method

In this paper, techniques for analyzing transient stability of power systems with field flux decays via Lyapunov´s direct method have been developed. First, Popov´s stability criterion has been generalized to one for systems with multi-argument non-linearities, and a Lur´e type Lyapunov function has been constructed in a systematic method. Next, the transient stability region has been defined, and its variation has been investigated in detail. As a result, the second type of instability has been introduced. By a numerical example, stability characteristics of the power system have been illustrated, and the validity of the Lyapunov function has been proved.