Measurement of turbine inflow with a 3D windscanner system and a spinnerlidar

UniTTe is a research project coordinated by DTU aiming to develop measurement procedures with nacelle mounted lidars for wind turbine power performance and loads assessment based on the inflow close to the rotor, i.e., within the rotor induction zone. This paper is presenting the first measurement campaign of UniTTe. Detailed measurements of the inflow to a 500 kW Nordtank wind turbine, at the DTU Risø Campus, have been taken simultaneously with the DTU short-range WindScanner system and the SpinnerLidar. This is a unique measurement campaign, combining high spatial and temporal resolution of the SpinnerLidar measurements and the 3 dimensional measurements of the short-range WindScanner system. The measurements were first validated against a sonic anemometer mounted on a mast, at 31.5 m a.g.l. and 48.7 m from the turbine. A good agreement was found between the measurements and the CFD model of the wind velocity decrease due to the rotor blockage effect and the induction, thus validating the inflow model.