One of the extreme load cases treated in the wind turbine certification is the extreme gust loading during operation. In the certification codes, it is treated in a deterministic way. A method of generating stochastic extreme gusts that includes the turbulence properties of the wind is described in this paper. For the moment, only the horizontal along wind direction of the wind speed is considered. The stochastic gusts are used to determine the gust responses. The gust responses are processed together with the probability density of the gust amplitude and mean wind speed to obtain the gust response distribution. Different distribution types, namely Rayleigh, Weibull, and Gumbel distributions, are applied to fit the distribution of the extreme gust responses. The estimated distributions are analyzed with statistical methods to determine the required number of simulations to obtain a reliable estimate of the statistical parameters of the distribution. The resulting structural responses to the stochastic gusts are compared to the gust response to the extreme operating gust specified in the IEC (International Electrotechnical Commission) design standard. The results show that the extreme gust response can differ significantly depending on the control concept. The response of the deterministic gust proposed in the IEC design code can also deviate considerably from the response of the stochastic gust depending on the turbine configuration. The aim of this work is to provide a rational approach to determine the extreme gust response. This theoretical method has not yet been verified with extensive measurements.

Issue Section:
Technical Papers
Keywords:
wind turbines, structural engineering computing, power engineering computing, wind, deterministic algorithms, stochastic processes, statistical analysis, probability
Topics:
Simulation, Wind, Wind turbines, Wind velocity, Probability, Turbines, Shapes, Turbulence
1.
Bierbooms, W., Drag, J. B, and Cleijne, H., 1999, “Verification of the Mean Shape of Extreme Gusts,” Wind Energy, John Wiley.
2.
IEC-TC88, 1997, Safety of Wind Turbine Generator Systems (Draft), IEC.
3.
Efron, B., and Tibshirani, R. J., 1993, An Introduction to the Bootstrap, Chapman and Hall, New York.
4.
Ferguson, M. C. (ed.), Ku¨hn M, Bierbooms W. A. A. M., Cockerill, T. T., Go¨ransson, B., Harland L. A., van Bussel, G. J. W., Vugts, J. H., and Hes, R., 1998, Opti-OWECS Final Report Vol. 4: A Typical Design Solution for an Offshore Wind Energy Conversion System, Institute for Wind Energy, Delft Univ. of Technology Delft.
5.
Zaaijer, M. B., 2000, DUWECS Reference Guide, Delft Univ. of Technology, Delft.
6.
Dragt, J. B., and Bierbooms W., 1996, “Modelling of Extreme Gusts for Design Calculations,” Proc. of European Union Wind Energy Conf., H. S. Stephens and Assoc., Go¨teborg pp. 842–845.
7.
Chaviaropoulos
,
P. K.
,
1997
, “
Probabilistic Analysis of Extreme Wind Events
,”
Wind Eng.
,
21
, No.
3
, pp.
139
–
159
, Multi-Science.
8.
Bierbooms, W. A. A. M., Cheng, P. W., Larsen, G., and Pedersen, B. J., 2000, “Modelling of Extreme Gusts for Design Calculations-NewGust,” Final Report JOR3-CT98-0239 Delft Univ. of Technology, Delft.
9.
Larsen, G. C., Bierbooms, W. A. A. M., and Hansen, K. S., 1999, “Mean Gust Shapes,” Risø National Laboratory Risø-R-1133(EN), Roskilde.
10.
HTTP://WWW.Winddata.Com
11.
Tromans, P. S., and Vanderschuren, L., 1995, “Response Based Design Method in the North Sea: Application of a New Method,” Proc. of 27th Offshore Technology Conf., Houston.
12.
Cheng, P. W., and Bierbooms, W. A. A. M., 1999, “Statistics of Extreme Loads for Wind Turbines,” Proc. of Int. Conf. of Wind Engineering, Copenhagen.
13.
Bierbooms, W. A. A. M., 2000, SWING4 User Manual, Delft Univ. of Technology, Delft.
14.
Cheng, P. W., and van Bussel, G. J. W., 2000, “Extreme Loading of Offshore Wind Turbines using Constrained Simulations,” Proc. of OWEMES Conf., Siracusa.
15.
Harland, L. A., Vugts, J. H., Jonathan, P., and Taylor, P. H., 1996, “Extreme Response of Non-Linear Dynamic Systems using Constrained Simulations,” Conf. of Offshore Mechanics and Arctic Engineering, Florence.
16.
Cartwright, D. E., and Longuet-Higgins, M. S., 1956, “The Statistical Distribution of the Maxima of a Random Function,” Proc. of Royal Society of London, A237, 212–232.
17.
Bergstro¨m, H., 1992, “Distribution of Extreme Wind Speed,” Wind Energy Report WE92:2, Dept. of Meteorology, Uppsala Univ., Uppsala.
Copyright © 2001
 by ASME
You do not currently have access to this content.