Around a quarter of the global wind energy capacity is operating in cold climates, where ice accretion can damage wind turbines, cause safety concerns and reduce power output. In this paper, alternative operational strategies to reduce ice build-up and increase power output are studied. The alternative strategies are achieved by making tip-speed ratio (TSR) modifications both during and after an icing event. To compare different TSR strategies, the concept of an energy payback time is outlined, which is used to determine when an alternative strategy outperforms a turbine's normal design strategy. The method is demonstrated using the NREL 5 MW reference wind turbine for twelve different icing conditions, encompassing different temperatures, wind speeds, droplet diameters and liquid water contents. The results indicate that for short and severe icing events, an alternative TSR strategy will start producing more energy than a conventional design strategy within 0.5–2.5 h after icing and decrease ice accumulation by approximately 25–30% per blade. The method presented in this study will enable more effective operational control strategies to be deployed for minimising ice-induced power losses and ice accretion at wind farms located in cold climates.
Bibliographical noteNOTICE: this is the author’s version of a work that was accepted for publication in Renewable Energy. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Renewable Energy, 145, (2020) DOI: 10.1016/j.renene.2019.08.023
© 2019, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
- Ice accretion
- Wind power
- Wind energy
- Tip-speed ratio (TSR)
- Icing events