Use of Prony analysis to extract sync information of low frequency oscillation from measured data

This paper describes methods to search the sync that takes place in power systems. Discrete signals in power systems can be expressed by the sum of several damped exponential sine functions. Therefore, dominant mode and residues included in the signals are estimated by applying parameter estimation methods. They are compared in their search for the sync among output signals. In the dominant oscillation mode included in many signals, the modes that have similar frequencies and damping constants were selected. By comparing their residues and phases, the sync of low frequency oscillations was examined. By identifying the sync of wide area oscillations, it was possible to differentiate between the generator and load characteristics. The sync exploring method proposed in this paper, together with sync indexes, were applied to a two area system and the KEPCO system to confirm that it is possible to search for the sync phenomenon in signals of large scale power systems. Copyright (C) 2010 John Wiley & Sons, Ltd.