Localizing Power-Grid Forced Oscillations Based on Harmonic Analysis of Synchrophasor Data

Harmonics in synchrophasor measurements of forced-oscillation events in the power grid are used to support localization of oscillation sources. A network-theoretic argument is presented which shows that harmonics at sufficiently high frequencies degrade quickly with spatial distance from the oscillation source, as compared to content at the fundamental frequency. Then, harmonics in synchrophasor measurements are analyzed for three historical forced-oscillation events with known oscillation sources. These data analyses confirm that harmonics are measurable in forced-oscillation responses, and further that they generally show faster spatial degradation as compared to the fundamental-frequency content. Based on these observations, we suggest techniques for localizing forced-oscillation sources based on ratios between signal content at the harmonics and the fundamental frequency.