Problems in the precise determination of BCU´s controlling unstable equilibrium points and PEBS´s exit point method in real-time transient stability analysis

In power systems transient stability assessment, direct methods have been used to estimate the critical clearing time for real-time application. Direct methods that use the controlling unstable equilibrium point concept are accepted as efficient to first swing transient stability analysis. However, some difficulties are observed in the determination of the interest points (PEBS exit point and controlling unstable equilibrium point) in such studies. The difficulties are inherent to the algorithms and are discussed on this paper as an attempt to find solutions to these difficulties.