Real time modal analysis of power system oscillations

This paper presents an FFT based real time modal analysis of power system oscillations in the frequency domain. The proposed real time monitoring system is set up by using a personal computer with a DSP board with an AD conversion interface. For the modal analysis of power system oscillations, the real power flow signal is utilized. The real power signal is sampled through the AD conversion interface and stored in the memory. Then, the well known FFT analysis is performed in real time on the DSP board to obtain the frequency spectrum. For the visualization of the FFT results, color mapping is utilized to show the variation of oscillation modes in real time. Furthermore, a fuzzy reasoning decomposition technique has been proposed to washout individual or grouped oscillation modes from the measured real power oscillations. The efficiency of the proposed method has been demonstrated through the real time testing by using various types of test signals