Ringdown Electromechanical Oscillations Analysis Through the Interpolated DFT Algorithm

This paper proposes the analysis of the ringdown electromechanical oscillations occurring in power systems through the two-point Interpolated Discrete Fourier Transform (IpDFT) algorithm for damped sinusoids. In particular, the frequency and the damping ratio of the modes of interest are estimated. The accuracy of the proposed algorithm is compared with that of a rather standard technique, i.e. the Prony algorithm, in order to evaluate the main advantages and disadvantages of either approach under different operating conditions. The results of several simulations show that the IpDFT algorithm is preferable when the signal-to-noise ratio is low or moderate, whereas the Prony algorithm is more robust to spectral interference when the oscillating modes are closely spaced in frequency.