The OWEZ Meteorological Mast. Analysis of mast-top displacements

NoordzeeWind carries out an extensive measurement and evaluation program as part of the OWEZ project. The technical part of the measurement and evaluation program considers topics as climate statistics, wind and wave loading, detailed performance monitoring of the wind turbines, etc. The meteorological measurements at the 116m high meteorological mast at the location of the wind farm are published on the project website and are widely used. Data at measurement sample frequency have been stored since May 2007 and recently have become available. From the acceleration measurements at the mast top, the displacements are reconstructed and the effect of these movements on the uncertainty of the wind speed measurements are estimated. From the acceleration measurements it is found that the influence of the mast-top movements on the wind speed measurements is limited and smaller than the flow distortion of the mast itself.