Effect of load uncertainty on small disturbance stability margins in open-access power systems

The paper is devoted to computation of the small signal damping bound caused by uncertainty in power system parameters (in particular in system load parameters). Methods of computation, reduction by means of revealing the most influential load parameters and expression in terms of security margins in the space of system parameters are addressed. The corresponding stability margin in the space of power system parameters can be taken into consideration in the procedures for finding the closest oscillatory stability boundary point and tracing these boundaries in given loading directions. The proposed method is tested on a realistic power system and results of simulation are presented and discussed. The techniques are not exclusive to but appear to be demanded by problems arising in open access grids