Monitoring changes in the soil and foundation characteristics of an offshore wind turbine using automated operational modal analysis
De Sitter, G.; Weijtjens, W.; El Kafafy, M.; Devriendt, C. (2013). Monitoring changes in the soil and foundation characteristics of an offshore wind turbine using automated operational modal analysis, in: Basu, B. (Ed.) Damage Assessment of Structures X. 10th International Conference on Damage Assessment of Structures (DAMAS), July 08-10, 2013, Dublin. Key Engineering Materials, 569-570: pp. 652-659. https://dx.doi.org/10.4028/www.scientific.net/KEM.569-570.652
In: Key Engineering Materials. Trans Tech Publications: Ädermannsdorf. ISSN 0252-1059; e-ISSN 1013-9826, more
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Document type: Conference paper
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| Keywords |
ANE, Belgium, Belgian Continental Shelf (BCS) [Marine Regions]
Marine/Coastal |
| Author keywords |
monitoring; offshore wind turbine; operational modal analysis; signal processing |
| Abstract |
This paper shows the first results of a long term monitoring campaign on an offshore wind turbine in the Belgian North Sea. It focuses on the vibration levels and resonant frequencies of the fundamental modes of the support structure. These parameters are crucial to minimize the O&M costs and to extend the lifetime of offshore wind turbine structures.For monopile foundations, scouring and reduction in foundation integrity over time are especially problematic because they reduce the fundamental structural resonance of the support structure, aligning that resonance frequency more closely to the lower frequencies. Since both the broadband wave energy and the rotating frequency of the turbine are contained in this low frequency band, the lower natural frequency can create resonant behavior increasing fatigue damage. Continuous monitoring of the effect of scour on the dynamics of the wind turbine will help to optimize the maintenance activities on the scour protection system.To allow proper continuous monitoring during operation, reliable state-of-the-art operational modal analysis techniques should be used. Those techniques are presented in this paper. The methods are also automated, so that the system can track the natural frequencies and damping ratios in a reliable manner. |
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