An initial study of ambient noise in synchrophasor measurements

The characteristics of ambient noise in synchrophasor measurements are investigated for different random load models. A theoretical discussion is provided relating the power spectral density (PSD) and probability density function (PDF) of the random load variations with the observed ambient noise in the synchrophasor measurements. The PSD and the PDF of ambient noise from actual synchrophasor measurements from the Western Electricity Coordinating Council (WECC) system were studied. Ambient noise was also simulated using a linearized simulation platform representing the WECC system. Both the theoretical and simulated results show that the ambient noise is approximately Gaussian when only wide-sense-stationary condition is met irrespective of the underlying distributions of the random load variations. In addition, the results show that the visibility of system modes in the noise spectrum remains unaffected for a wide-range of statistically different white, filtered white, and pink random load models.