The wind field in front of the rotor will be measured with both continuous wave (ZephIR) and pulsed (Avent) nacelle lidars. WP2 will develop procedures for the calibration of these nacelle lidars (R2). In order to be acceptable in the context of contractual measurements, the lidars will need traceable calibrations. Some headway has already been made in calibrating two-beam pulsed nacelle lidars but this work must be extended to profiling nacelle lidars.
Task 2.1 Procedure for the calibration of profiling nacelle lidars
Task 2.1 is concerned with analysing the requirements and drafting the procedures for the calibrations. Parameters that need to be calibrated or verified need to be identified and a methodology described to perform the testing. Apart from wind speed, geometrical parameters such as beam opening angles and the measurement of the beam tilting will need to be considered. In all cases, a comprehensive measurement uncertainty budget will be included.
Task 2.2 Calibration of both lidars to be used in the measurement campaigns
Task 2.2 refers to the actual physical testing that will be carried out using the procedures defined in the previous task. The measurements will take place at the DTU Test Station for Large Wind Turbines, in Høvsøre, where highly instrumented meteorological masts can be used as references. After this calibration, both lidars will be deployed on wind turbines.
Task 2.3 In-house factory calibration
Field calibration is slow and expensive. As an alternative, the possibility of in-house factory calibrations will be investigated by the lidar manufacturers, either by assessing the uncertainty budget from each of the major components or by dedicated local testing.