ANALYSIS OF POWER SYSTEM LOW FREQUENCY OSCILLATION WITH EMPIRICAL MODE DECOMPOSITION

The low frequency oscillation (LFO) in power systems often consists of composite responses of various oscillation modes. Thus a direct analysis of LFO for revealing system dynamic characteristics is not straightforward. The primary objective of this study is to utilize the method of empirical mode decomposition (EMD) to expand the LFO response under study into multiple intrinsic mode functions (IMFs) for detailed investigation of power system dynamics. Then time-frequency power information is explored using wavelet transform to obtain time-frequency power graph which is further resolved into a time-frequency-power diagram. Finally, information from the time-frequency-power diagram is further examined to determine those generators that demonstrate higher degree of participation in the LFO of power system. The comparative analysis in frequency domain shows that, at specific frequencies in LFO modes, higher oscillation participation power also shows a larger participation factor in its frequency domain analysis.