Synchrophasor measurement‐based correlation approach for dominant mode identification in bulk power systems

Abstract

This study proposes a novel synchrophasor measurement-based correlation approach to identify the dominant oscillation modes in bulk power systems. In the proposed approach, the reference channel (RC) of cross-correlation (CC) is optimally selected based on residue analysis. With the selected RC, the CC of field-measurement data is formed to extract the free-decay system responses. Then, eigensystem realisation algorithm (ERA) is applied to the extracted responses to estimate the system state-space model. A practical model order selection strategy for ERA is proposed to determine the system model order. Further, cross-coherence spectrum is employed to distinguish the dominant modes from the eigenvalues of the estimated state-space model. The proposed method can achieve accurate and robust solutions in the presence of different levels of errors and noises in measurement data. The effectiveness of the proposed method has been verified in a 16-generator, 68-bus test system as well as the China Southern Power Grid system.