Impact of grid modeling level on the assessment of power grid stability

Matthias Gries, Philipp Maass
Fachbereich Physik, Universität Osnabrück, Germany

A higher percentage of electrical power provided by renewable energy sources is accom-panied with increasing oscillations in the power generation. This can have a negative e˙ect on the frequency stability on di˙erent time scales reaching from sub-seconds to seasons. There are already studies on the impact of these oscillations on short time scales [1]. Especially the non-Gaussian features of wind speed and power input statistics pose a threat for the stability [2].
We provide an extension of these studies by comparing di˙erent power grid realizations under a perturbation of the frequency and the power injection. The fluctuating power input is implemented by transforming wind velocities measured at a research platform located in the north sea. Our stability analysis includes di˙erent treatments for the consumers, di˙erent voltage levels, as well as structural properties like internal nodes and the related Kron reduction.
It is shown that the results can vary strongly depending on the modeling level of the grid [3]. Not only the stability assessment can change but also the location of weak spots in the grid and the frequency statistics.

References:

[1]    Sabine Auer, Frank Hellmann, Marie Krause, and Jürgen Kurths. Stability of synchrony against local intermittent fluctuations in tree-like power grids. Chaos, 27(12):127003, 2017.
[2]    Katrin Schmietendorf, Joachim Peinke, and Oliver Kamps. The impact of turbulent renewable energy production on power grid stability and quality. The European Physical Journal B, 90(11):222, Nov 2017.
[3]    Matthias F. Wol˙, Pedro G. Lind, and Philipp Maass. Power grid stability under perturbation of single nodes: E˙ects of heterogeneity and internal nodes. Chaos: An Interdisciplinary Journal of Nonlinear Science, 28(10):103120, 2018.