Microscopic fluctuations in power-grid frequency recordings at the sub-second scale

TL;DR

This paper investigates the complex, multi-fractal fluctuations of power-grid frequency at sub-second scales, revealing dynamic changes and proposing a stochastic model to explain these phenomena.

Contribution

It demonstrates that power-grid frequency exhibits fundamental dynamic changes below one second and introduces a stochastic model to replicate these observed behaviors.

Findings

Increased power spectral density below 1 second

Emergence of multifractality at sub-second scales

Correlation behavior changes at high resolution

Abstract

Complex systems, such as the power grid, are essential for our daily lives. Many complex systems display (multi-)fractal behavior, correlated fluctuations and power laws. Whether the power-grid frequency, an indicator about the balance on supply and demand in the electricity grid, also displays such complexity remains a mostly open question. Within the present article, we utilize highly resolved measurements to quantify the properties of the power-grid frequency. We show that below 1 second, the dynamics may fundamentally change, including a suddenly increasing power spectral density, emergence of multifractality and a change of correlation behavior. We provide a simplified stochastic model involving positively correlated noise to reproduce the observed dynamics, possibly linked to frequency dependent loads. Finally, we stress the need for high-quality measurements and discuss how we obtained the data analyzed here.