LeikLine

Primary objective of the project is to develop a cost-efficient, flexible and practical method for the assessment of power curves from wind turbines in offshore wind farms. For a turbine in free-stream conditions, we follow the standard procedure in IEC 61400-12-1, replacing the met. mast by a floating LiDAR system (FLS). For a turbine that is not in free stream but in the wake of one or more other turbines we first simulate the flow in the relevant part of the wind farm. The simulation results are used to correct the wind data measured by the FLS in the wind farm. The lidar buoy is to be installed between two wind turbines and is both directly in front of the turbine that is to be assessed and in the wake of the other turbine. The wind measurement of the FLS is thus affected by the turbine wake, and the resulting inhomogeneity needs to be considered for the reconstruction and correction of the wind measurements. For the selection of the waked turbine one with a significant reduced performance may be considered.

In detail, the following (partial) objectives are covered by the LeikLine project:

• Installation and operation of the Fraunhofer IWES Wind Lidar Buoy for measuring wind speeds in front of a wind turbine in free stream and in the wake of another turbine in an offshore wind farm (in two dedicated parts of a measurement campaigns)
• Derivation of the power curve from the FLS measurement data (for wind speed) and the performance data of the wind turbine in free stream
• Derivation of the power curve from the FLS measurement data (for wind speed) and the performance data of the turbine in the wake together with simulated wind flow data, development of a corresponding correction approach

Development and documentation of a practical method for measuring offshore power curves and presentation of results in relevant expert groups (with focus on standardisation)