Test planning and operational modal analysis of a wind turbine tower; application to its dynamic behavior

Document Type : Full Length Article

Authors

1 Ph.D Candidate, Department of Mechanical Engineering, Malek-E-Ashtar University of Technology, Isfahan, Iran

2 Assistant Professor, Mechanical engineering department, Malek-E-Ashtar university of technology, Isfahan, Iran, Isfahan, Iran

3 Professor, Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran

10.22064/tava.2021.136290.1173

Abstract

Thorough knowledge of the wind turbine (WT) dynamics is necessary to efficiently improve its design, operation, and maintenance. Due to the wind turbine's large size, there are difficulties in measuring and excitation of full-scale WTs in general modal tests. Because of the issue, the designers may rely on finite elements and numerical models. Nevertheless, by considering the advantages of operational modal analysis relative to the experimental modal analysis, it is an efficient way to understand the dynamics behavior of WT based on the actual operation installed turbine at the site. With regard to performing operational modal analysis and achieving acceptable results, proper test planning has great importance. Initially,in this article, test planning steps will be described for the studied WT's successful operation modal test. Then the modal analysis results will be revealed, and finally, the dynamic behavior of the WT will be discussed based on the modal results

Highlights

  • Required Test planning for a successful OMA of the wind turbine is considered.
  • Finite element modal analysis of the studied wind turbine is presented.
  • Operational Modal Analysis of the wind turbine tower carried out, and modal results are given.
  • The wind turbine’s dynamic behavior is discussed usingits identified modal parameter.

Keywords

Main Subjects


[1] T.G. Carne, G.H. James III, The inception of OMA in the development of modal testing technology for wind turbines, Mechanical Systems and Signal Processing, 24 (2010) 1213-1226.
[2] R. Osgood, G. Bir, H. Mutha, B. Peeters, M. Luczak, G. Sablon, Full-scale modal wind turbine tests: comparing shaker excitation with wind excitation, in:  Structural Dynamics and Renewable Energy, Volume 1, Springer, 2011, pp. 113-124.
[3] R. Shirzadeh, W. Weijtjens, P. Guillaume, C. Devriendt, The dynamics of an offshore wind turbine in parked conditions: a comparison between simulations and measurements, Wind Energy, 18 (2015) 1685-1702.
[4] R. Shirzadeh, C. Devriendt, M.A. Bidakhvidi, P. Guillaume, Experimental and computational damping estimation of an offshore wind turbine on a monopile foundation, Journal of Wind Engineering and Industrial Aerodynamics, 120 (2013) 96-106.
[5] W. Weijtjens, T. Verbelen, E. Capello, C. Devriendt, Vibration based structural health monitoring of the substructures of five offshore wind turbines, Procedia engineering, 199 (2017) 2294-2299.
[6] E.A. Camargo, J.P. Ulfkjaer, R. Brincker, J. Nøergaard, S.S. Gadegaard, Operational Modal Analysis and Finite-Element Model Updating of Pilot Concrete Wind Turbine Tower, Journal of Structural Engineering, 145 (2019) 05018003.
[7] W.-H. Hu, S. Thöns, R.G. Rohrmann, S. Said, W. Rücker, Vibration-based structural health monitoring of a wind turbine system. Part I: Resonance phenomenon, Engineering Structures, 89 (2015) 260-272.
[8] M. Ozbek, F. Meng, D.J. Rixen, Challenges in testing and monitoring the in-operation vibration characteristics of wind turbines, Mechanical Systems and Signal Processing, 41 (2013) 649-666.
[9] E. Di Lorenzo, G. Kosova, U. Musella, S. Manzato, B. Peeters, F. Marulo, W. Desmet, Structural Health Monitoring challenges on the 10-MW offshore wind turbine model, in:  Journal of Physics: Conference Series, IOP Publishing, 2015, pp. 012081.
[10] D. Tcherniak, C. ., S., M.H. Hansen, Limits of Operational Modal Applicability Analysis to Operational Wind Turbines, in:  Proc. 28th Int. Modal Analysis Conference (IMAC-XXVIII). 2010.
[11] R. Brincker, C. Ventura, Introduction to operational modal analysis, John Wiley & Sons, 2015.
[12] D. Tcherniak, S. Chauhan, M. Rossetti, I. Font, J. Basurko, O. Salgado, Output-only modal analysis on operating wind turbines: application to simulated data, in:  Proceedings of European Wind Energy Conference, 2010, pp. 1-10.
[13] P. Van Overschee, B.L. De Moor, Subspace identification for linear systems: Theory—Implementation—Applications, Springer Science & Business Media, 2012.
[14] V. Boonyapinyo, T. Janesupasaeree, Data-driven stochastic subspace identification of flutter derivatives of bridge decks, Journal of Wind Engineering and Industrial Aerodynamics, 98 (2010) 784-799.
[15] T. Knudsen, Consistency analysis of subspace identification methods based on a linear regression approach, Automatica, 37 (2001) 81-89.
[16] M.J. Kuhn, Dynamics and Design Optimization of Offshore Wind Energy Conversion Systems, in:  Delft University of Technology, 2001.
[17] E. Hau, H. von Renouard, The wind resource, Wind Turbines: Fundamentals, Technologies, Application, Economics, (2006) 451-483.
[18] G. Zhang, B. Tang, G. Tang, An improved stochastic subspace identification for operational modal analysis, Measurement, 45 (2012) 1246-1256.