Multi-Channel Enhanced Synchro-Reassignment Transform for Robust Identification of Sub/Super-Synchronous Oscillations Using Synchronized Measurements

Abstract

Synchrophasor-based sub-synchronous oscillations (SSOs) parameter identification is effective for monitoring SSOs, while its performance is significantly degraded by measurement noise, posing challenges to reliable parameter identification. This paper proposes a novel technique using multi-channel enhanced synchro-reassigning transform (MESRT) for robust and accurate SSO parameter identification. First, each measurement channel is transformed using the short-time Fourier transform (STFT) to construct a global multi-channel time-frequency (TF) representation. Then, an average modal energy-based strategy is developed to eliminate noise-induced spurious modes in the STFT spectrum. Subsequently, a three-step selection rule is applied to extract TF coefficients representing oscillation modes, from which the time-domain components are reconstructed. Finally, the Hilbert transform (HT) method is employed to identify the oscillation frequency and damping factor of each mode. The proposed MESRT method effectively improves the noise immunity and accuracy of conventional SRT by considering inter-channel correlations and leveraging modal energy to remove spurious modes. Case studies validate that the proposed method performs exceptionally well in terms of accuracy and noise robustness, demonstrating superior performance compared to existing methods.