Abstract
In this paper a uniform version of LaSalle's Invariance Principle is used in order to give support for the proposal of a transient stability analysis of a power system which is robust with respect to post-fault parameter uncertainties. An estimate of the attraction area which is independent of the system parameters and is contained into the real attraction area is obtained. Using these ideas, a robust version of the PEBS- potential energy boundary surface-method is proposed and the methodology is tested in a sub-system of the South Brazilian System. A promising application for the proposed methodology could be contingency analysis.