Dynamic Aggregation and the Calculation of Transient Stability Incides

A method of dynamic aggregation is introduced to define power system transient stability indices based on the previously used concepts of potential and kinetic energies. The indices are easier to compute and less conservative than those introduced by other authors. They reflect quantitatively the seriousness of the system instability threat created by actual or postulated faults. They are thus useful for purposes of on-line system security monitoring and interpretation of transient stability studies.