Understanding the inception of 14.7 Hz oscillations emerging from a data center

Abstract

As Dominion Energy's power grid has grown to include an increasing number of inverter-based resources and power electronic components, we have begun to observe an increase in previously unforeseen and difficult-to-explain dynamic behaviors. In this paper, we present a measurement-based analysis of 14.7–14.8 Hz oscillations emerging from a data center in Dominion Energy's power grid. Synchrophasor data collected over several months were analyzed using non-parametric spectral analysis approaches to understand its inception and, more importantly, to characterize its behavior. What makes this case unique is the presence of an independent and unplanned exogenous excitation in the system. This excitation plays a critical role in understanding the inception and emergence of an otherwise unobservable dynamic process that, as it destabilizes, results in oscillations at a higher and narrow frequency range than that of conventional power system dynamics.