A spinner-integrated wind lidar for enhanced wind turbine control

T. Mikkelsen, N. Angelou, K. Hansen, M. Sjöholm, M. Harris, C. Slinger, P. Hadley, R. Scullion, G. Ellis, G. Vives
2012 Wind Energy  
Harris, M.; Slinger, C.; Hadley, P.; Scullion, R.; Ellis, G.; Vives, G. ABSTRACT A field test with a continuous wave wind lidar (ZephIR) installed in the rotating spinner of a wind turbine for unimpeded preview measurements of the upwind approaching wind conditions is described. The experimental setup with the wind lidar on the tip of the rotating spinner of a large 80 m rotor diameter, 59 m hub height 2.3 MW wind turbine (Vestas NM80), located at Tjaereborg Enge in western Denmark is
more » ... Preview wind data at two selected upwind measurement distances, acquired during two measurement periods of different wind speed and atmospheric stability conditions, are analyzed. The lidar-measured speed, shear and direction of the wind field previewed in front of the turbine are compared with reference measurements from an adjacent met mast and also with the speed and direction measurements on top of the nacelle behind the rotor plane used by the wind turbine itself. Yaw alignment of the wind turbine based on the spinner lidar measurements is compared with wind direction measurements from both the nearby reference met mast and the turbine's own yaw alignment wind vane. Furthermore, the ability to detect vertical wind shear and vertical direction veer in the inflow, through the analysis of the spinner lidar data, is investigated. Finally, the potential for enhancing turbine control and performance based on wind lidar preview measurements in combination with feed-forward enabled turbine controllers is discussed. Remote sensing-based wind measurement technology, called wind lidar, short for light detection and ranging, has been around since the early 1970s and is similar to radar in the sense that it relies on the transmission of electromagnetic energy and then analyzes the return that bounces back to determine information about the atmospheric objects from which the electromagnetic energy or waves scatter. For example, the speed of a scattering object can be found from detecting the change in the backscattered wave's frequency (the well-known Doppler effect). The key difference, however, between lidar and radar is the transmitted wavelength and the size of the scattering objects. The lidar used here has light waves that are only micrometers (1.55 mm) in wavelength. At this wavelength, radiation in the atmosphere is mainly Mie scattered and hence Doppler shifted by many tiny, micrometer small in size, naturally occurring aerosols and particles in the atmospheric boundary layer such as dust, water droplets, pollution, pollen and salt crystals that are suspended and drifting along at the speed of the wind. Lidar potential for load reduction and increased power production The advances in optical fiber technology and telecom component-based wind lidar remote sensing 1-7 have recently spurred renewed interest for improving wind energy cost-effectiveness through wind turbine-integrated lidar systems, providing upwind prevision of incoming wind fields in combination with advanced feed-forward control. WIND ENERGY Wind Energ. (2012) Published online in Wiley Online Library (wileyonlinelibrary.com).
doi:10.1002/we.1564 fatcat:7fktrd57q5d33oyskdge3wzbwe