On-line identification of power system oscillation modes by using real time FFT

This paper presents a real time FFT based online identification for the real time monitoring of power system oscillation modes. The monitoring system is set up by using a personal computer with a DSP board, which has AD and DA conversion interfaces. For the identification of oscillation modes, the real power flow signal is utilized. The real power signal is sampled through the AD conversion interface and stored in the memory. The monitored signal is passed to the workspace in the Matlab/Simulink environment for the FFT analysis and also the visualization of the FFT results by using a color mapping to show the variation of oscillation modes in real time. Furthermore, a fuzzy reasoning based mode decomposition has been proposed to identify individual mode of oscillations included in the measured real power signals. The efficiency of the proposed method has been demonstrated through the real time testing by using various types of test signals