A coherence method for detecting and analyzing oscillations

In this paper, a coherence method is proposed to detect and analyze forced oscillations from phasor measurement unit data. The calculation of coherence spectrum is reviewed, and forced oscillations are related to the peaks in the coherence spectrum. Using simulation and field measurement data, the proposed coherence method's performance is compared with the power spectral density method. When applied to detect and analyze forced oscillations under low signal noise ratio conditions, the proposed coherence method shows better performance.