Investigation of spatial gusts with extreme rise time on the extreme loads of pitch-regulated wind turbines
Article first published online: 16 DEC 2004
Copyright © 2004 John Wiley & Sons, Ltd.
Special Issue: The Science of Making Torque from Wind. Part II: Wind, Loads, Materials and Structures
Volume 8, Issue 1, pages 17–34, January/March 2005
How to Cite
Bierbooms, W. (2005), Investigation of spatial gusts with extreme rise time on the extreme loads of pitch-regulated wind turbines. Wind Energ., 8: 17–34. doi: 10.1002/we.139
- Issue published online: 16 DEC 2004
- Article first published online: 16 DEC 2004
- Manuscript Accepted: 8 SEP 2004
- Manuscript Revised: 3 SEP 2004
- Manuscript Received: 29 APR 2004
- gust models;
- extreme wind conditions;
- wind field simulation;
It is assumed that the extreme loading of pitch-regulated turbines is caused by gusts with an extreme rise time rather than an extreme gust amplitude. A special kind of wind field simulation, so-called constrained stochastic simulation, is dealt with in order to generate the desired gusts. Just as in wind field simulation for fatigue purposes, it is assumed that turbulence is Gaussian; a possibility is mentioned of how to deal with non-Gaussian behaviour. On the basis of the presented theory it can be stated that the stochastic gusts produced in this way are, in a statistical sense, not distinguishable from gusts selected from a (very long) time series. An example of a spatial gust as well as the mean spatial gust shape is shown. For a reference turbine the maximum blade root flapping moment has been determined as a function of the gust centre in the rotor plane; the maximum response is obtained in the case where the gust hits one of the rotor blades at 75% of the radius. When the gust duration is large compared with the integral time constant of the controller, the controller can handle the gust as expected. However, even for small rise times it turns out that the maximum flap moment due to the gust is not significantly higher than that due to the background turbulence and 1P excitations. This may indicate that perhaps extreme rise time gusts do not lead to extreme loading of pitch-regulated wind turbines. For a final judgement a proper probabilistic approach is necessary; an outline of such an approach has been sketched. Furthermore, it is recommended to do research on other gust types in order to find out the type which leads to the extreme wind turbine loading. Copyright © 2004 John Wiley & Sons, Ltd.