ECN publication
Optical motion analysis of wind turbines
Published by: Publication date:
ECN 1996
ECN report number: Document type:
ECN-RX--96-043 Other
Number of pages: Full text:
5 Download PDF  

This study aims at discovering the pros and cons of optical motionanalysis of large wind turbines. An optical motion analysis technique used in other fields of science is applied for the first time to a wind turbine. Modes of motion of the tower and the blades were measured dynamically and accurately in only a few weeks, including preparation time. Two video cameras observe retroreflective markers placed on the blades and tower of a wind turbine. The image data is processed into 3d-coordinates of the marker centres. From the calculated moving marker centres, e.g. flap, lead/lag modes, eigenfrequencies, teeter motion and tower motion can be calculated straightforward. We will present the flap angles of the blades of a rotating wind turbine, which were determined with a frequency of 100 Hz and a standard deviation of 0.1"o. The benefits of this optical method are: direct dynamic and accurate measurement of blade and tower positions, no influence on flow or turbine, no electrical connections, fast set-up and execution, applicable to full scale turbines at low cost. 3 figs., 1 ref.

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