STABILITY BOUNDARY APPROXIMATION OF A POWER-SYSTEM USING THE REAL NORMAL-FORM NF VECTOR-FIELDS

This paper presents a method to approximate the stability boundary of the postfault stable equilibrium point of a power system using the rea l normal form of vector fields. We first explain the method of approxi mating the invariant manifolds of an equilibrium point via second orde r normal forms, and present an instructive example. The proposed metho d is then used to analyze an 11 generator test system. For two differe nt fault scenarios and different loading conditions, we determine the controlling unstable equilibrium point, study the change of this UEP u nder increased loading, find the approximation to the stability bounda ry, and discuss the change of its shape. Finally, the behavior of syst em trajectories near the UEP and the stability boundary is described.