The development of wind energy is hindered by measurement problems: in particular the fluctu-ating wind speed introduces large uncertainties. For example: to confirm a theoretical improve-ment of around 5% in production of a new design by field experiments is very hard to almost impossible. As long as convincing field tests have not confirmed the actual improvement, the industry will not invest much to change the turbine design. This is an example that clarifies why the development of wind energy is hindered by metrology problems (measurement problems). Other examples are in the fields of: - Warranty performance measurements - Improvement of aerodynamic codes - Assessment of wind resources In general terms the uncertainty of the testing techniques and methods are typically much higher than the need. Since this problem covers many areas of wind energy, the work package is de-fined as a crosscutting activity. The problem is especially relevant for the following areas: Production related - Power performance testing especially in wind farms - Testing of turbine improvements in the order of several percent - Testing of aerodynamic codes - Testing of turbine response to effects such as turbulence and shear Load related - Mechanical load measurements in farms aimed at verification of aero elastic codes. (blade root moments, yaw moments, tower foot moments etc.) Wind related - Measurement of wake effects and wind resources inside wind farms - Measurements of inter farm effects (regarding velocity profiles, turbulence, surface shear recovery distances etc) - Measurements of the interaction wind farms and microclimate The objectives of the metrology work package are to develop metrology tools in wind energy to significantly enhance the quality of measurement and testing techniques. The development of the basic metrology measures is done by - Identifying all relevant measurands within the wind energy community - Describing their definition in detail - Identifying all relevant influence parameters - Quantifying their systematic influence on measurements - Specifying traceability and - Applying advanced uncertainty analysis methods. This report presents a state of the art assessment to identify all relevant measurands. The re-quired accuracies and required sampling frequencies are stated from the perspective of the users of the data (the other work packages in UPWIND). The interaction with the other work pack-ages has initiated internal debates which led to feedback to this list of measured parameters.
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Energy Research Centre of the Netherlands (ECN), 2007