Research on Identification Method of Subsynchronous Oscillation Parameters Based on FSST and STD

With the aim of double carbon in China, the incorporation of a significant quantity of novel energy devices and dynamic compensation devices and dynamic compensation devices into the grid has caused many instances of sub-synchronous oscillation (SSO) incidents, which have a considerable impact on the secure and stable operation of the power system. Rapid identification of SSO parameters can provide characteristic parameters for suppression measures, real-time warning, and analysis of SSO. Therefore, this paper proposes a time-frequency analysis approach based on the Short-Time Fourier Transform (STFT) and incorporates it with the Sparse Time Domain (STD) technique for the identification of sub-synchronous oscillation parameters. The proposed method first applies the SST time-frequency domain transformation to the oscillation data collected by Phasor Measurement Unit (PMU) at key nodes in the power grid, decomposing a set of signals with multiple modes into different modal components. Subsequently, an improved ridge extraction method is employed to reconstruct the time-frequency domain signals of each mode. The STD method is subsequently employed to precisely identify the modal parameters of SSO. Finally, through the analysis and verification of ideal examples and real-world power grid data, the identification results demonstrate the accuracy, robustness, and computational efficiency of the proposed method, thus satisfying practical engineering applications.