Optical Measurements and Operational Modal Analysis on a Large Wind Turbine: Lessons Learned

2011 ◽  
pp. 257-276 ◽  
Author(s):  
Muammer Ozbek ◽  
Daniel J. Rixen
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Lessons Learned ◽  
Operational Modal Analysis ◽  
Optical Measurements ◽  
Large Wind

Monitoring Changes in the Soil and Foundation Characteristics of an Offshore Wind Turbine Using Automated Operational Modal Analysis

2013 ◽  
Vol 569-570 ◽  
pp. 652-659 ◽  
Author(s):  
Gert de Sitter ◽  
Wout Weitjens ◽  
Mahmoud El-Kafafy ◽  
Christof Devriendt
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Continuous Monitoring ◽  
Low Frequency ◽  
Operational Modal Analysis ◽  
Human Interaction ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Support Structure ◽  
Lower Natural Frequency

This paper will show the first results of a long term monitoring campaign on an offshore wind turbine in the Belgian North Sea. It will focus on the vibration levels and resonant frequencies of the fundamental modes of the support structure. These parameters will be crucial to minimize O&M costs and to extend the lifetime of offshore wind turbine structures. For monopile foundations for example, 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 a proper continuous monitoring during operation, reliable state-of-the-art operational modal analysis techniques should be used and these are presented in this paper. The methods are also automated, so that no human-interaction is required and the system can track the natural frequencies and damping ratios in a reliable manner.

scholarly journals Nonlinear Aeroelastic Modal Analysis of Large Wind Turbine Flexible Blades

2020 ◽  
Vol 56 (14) ◽  
pp. 180
Author(s):  
HUANG Jundong ◽  
XIA Hongjian ◽  
LI Deyuan ◽  
GUO Kunxiang
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Large Wind

scholarly journals Structural health monitoring of offshore wind turbines using automated operational modal analysis

2014 ◽  
Vol 13 (6) ◽  
pp. 644-659 ◽  
Author(s):  
Christof Devriendt ◽  
Filipe Magalhães ◽  
Wout Weijtjens ◽  
Gert De Sitter ◽  
Álvaro Cunha ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Wind Turbines ◽  
Operational Modal Analysis ◽  
Offshore Wind ◽  
Dynamic Monitoring ◽  
Mode Shapes ◽  
Offshore Wind Turbine ◽  
Complex Frequency ◽  
Offshore Wind Turbines

This article will present and discuss the approach and the first results of a long-term dynamic monitoring campaign on an offshore wind turbine in the Belgian North Sea. It focuses on the vibration levels and modal parameters of the fundamental modes of the support structure. These parameters are crucial to minimize the operation and maintenance costs and to extend the lifetime of offshore wind turbine structure and mechanical systems. In order to perform a proper continuous monitoring during operation, a fast and reliable solution, applicable on an industrial scale, has been developed. It will be shown that the use of appropriate vibration measurement equipment together with state-of-the art operational modal analysis techniques can provide accurate estimates of natural frequencies, damping ratios, and mode shapes of offshore wind turbines. The identification methods have been automated and their reliability has been improved, so that the system can track small changes in the dynamic behavior of offshore wind turbines. The advanced modal analysis tools used in this application include the poly-reference least squares complex frequency-domain estimator, commercially known as PolyMAX, and the covariance-driven stochastic subspace identification method. The implemented processing strategy will be demonstrated on data continuously collected during 2 weeks, while the wind turbine was idling or parked.

scholarly journals Virtual Structural Monitoring of Wind Turbines Using Operational Modal Analysis Techniques

2013 ◽  
Vol 569-570 ◽  
pp. 523-530 ◽  
Author(s):  
Emilio di Lorenzo ◽  
Simone Manzato ◽  
Bart Peeters ◽  
Herman van der Auweraer
Keyword(s):  
Modal Analysis ◽  
Wind Turbines ◽  
Numerical Models ◽  
Structural Condition ◽  
Operational Modal Analysis ◽  
Critical Aspect ◽  
Operational Conditions ◽  
Open Issue ◽  
Output Only ◽  
Large Wind

Operational Modal Analysis (OMA), also known as output-only modal analysis, allows identifying modal parameters only by using the response measurements of the structures in operational conditions when the input forces cannot be measured. These information can then be used to improve numerical models in order to monitor the operating and structural conditions of the system. This is a critical aspect both for condition monitoring and maintenance of large wind turbines, particularly in the off-shore sector where operation and maintenance represent a high percentage of total costs. Although OMA is widely applied, the wind turbine case still remains an open issue. Numerical aeroelastic models could be used, once they have been validated, to introduce virtual damages to the structures in order to analyze the generated data. Results from such models can then be used as baseline to monitor the operating and structural condition of the machine.

scholarly journals Numerical Simulation and Modal Analysis of External Flow Field of Large Wind Turbine

2019 ◽  
Vol 1314 ◽  
pp. 012019
Author(s):  
Boqiang Zhang ◽  
Xinping Wu ◽  
Zhiqiang He ◽  
Zhentao Li ◽  
Sutao Bi
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Wind Turbine ◽  
Modal Analysis ◽  
External Flow ◽  
Large Wind
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