Nonlinear Nonstationary Analysis Techniques for Mode Shape Estimation in Power Systems

Inspection of Low frequency oscillation is highly crucial in the context of modern power system operation and control. A dynamic approach is needed for exact estimation of the mode shape at low-frequency modes. Signal decomposition techniques and spectral analysis were adapted in this paper. Since the signal quality is weak, it is needed to identify the low-frequency mode prior to spectral analysis. The power spectral density is used to process dominant modes which indicate centre frequencies in the spectrum. Variational mode decomposition is proposed in place of empirical mode decomposition so as to provide a better-quality way of analysis of low-frequency mode and mode shape determination, and it is tested on real-time data from the power grid.