Analysis of low frequency oscillations in power system based on HHT technique

In this paper, A non-linear analysis tool based on Hilbert-Huang Transform (HHT) is used to extract time-varying oscillations characteristics from the information provided by Wide Area Measurement System(WAMS). The filtered signal is decomposed into finite numbers Intrinsic Mode Functions (IMFs) by Empirical Mode Decomposition (EMD), and then the instantaneous parameters, including frequency, amplitude and damping ratio of dominant IMF will be obtained by Hilbert Transform (HT) and specific calculating formula. Both the results of simulations and the actual applications in power system show that it is a powerful tool for the oscillation research.