Long Term Characteristics of Ultra Low Frequency Oscillations in the Nordic Power System

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Journal Title
Journal ISSN
Volume Title
Conference article in proceedings
Date
2022
Major/Subject
Mcode
Degree programme
Language
en
Pages
5
Series
Proceedings of 2022 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2022, IEEE PES Innovative Smart Grid Technologies Conference Europe, Volume 2022-October
Abstract
In the Nordic power system, the frequency of the system oscillates constantly around the nominal 50 Hz value with a period of around 40 to 90 s, i.e., in the frequency range around 0.011-0.025 Hz. This ultra low frequency oscillation (ULFO) deteriorates the frequency quality in the entire system, causes unnecessary control actions and may cause wear and tear of turbines. In the worst case, the oscillation may endanger frequency stability of the system. This paper analyzes the properties of this oscillations during a period of seven years using an ambient modal identification method (mode meter). The paper shows that the ULFOs can be analyzed using ambient modal identification methods and a similar approach is recommended to be used for analyzing ULFOs in other power systems as well. Furthermore, the paper gives insight into the long term characteristics of the ULFOs in the Nordic power system and the results indicate that for example the amplitude of the ULFOs has an increasing trend during the analysis period (and their damping has a decreasing trend). These findings indicate a need for monitoring the ULFOs and develop actions for mitigating them.
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Publisher Copyright: © 2022 IEEE.
Keywords
Frequency control, frequency stability, inertia, modal identification, ultra low frequency oscillation
Other note
Citation
Seppanen, J, Lehtonen, M, Kuivaniemi, M & Haarla, L 2022, Long Term Characteristics of Ultra Low Frequency Oscillations in the Nordic Power System . in Proceedings of 2022 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2022 . IEEE PES Innovative Smart Grid Technologies Conference Europe, vol. 2022-October, IEEE, IEEE PES Europe Conference on Innovative Smart Grid Technologies, Novi Sad, Serbia, 10/10/2022 . https://doi.org/10.1109/ISGT-Europe54678.2022.9960643