On-line method for determining power system transient stability

Abstract

A fast and reliable method for determining power system transient stability is presented for on-line power system dynamic security assessment. This method is based on the direct (Lyapunov theory) approach controlling the unstable equilibrium point (UEP). Lyapunov technique, however, cannot be used on-line, since calculating the controlling UEP is a computational intensive problem, even for a computer. The invention comprises determining the controlling UEP of a reduced system and relates the controlling UEP of the reduced system to the controlling UEP of the original system. The invention has a sound theoretical basis. The invention eliminates the difficulty of having to find the controlling UEP. The method of the invention determines the constant energy region that surrounds the controlling UEP of the original system. This region is used to approximate the stability region boundary intersection point that a particular fault trajectory will traverse.

Dependencies are inferred from the claim text.