An overview of wind related metrology research made at Risø DTU over
the period of the UPWIND project is given. A main part of the overview is
devoted to development of the Lidar technology with several sub-chapters
considering different topics of the research. Technical problems are not rare
for this new technology, and testing against a traditional met mast have
shown to be efficient for gaining confidence with the ground based Lidar
technology and for trust in accuracy of measurements. In principle, Lidar
measurements could be traceable through the fundamental measurement
principles, but at this stage of development it is not found feasible. Instead,
traceability is secured through comparison with met masts that are traceable
through wind tunnel calibrations of cup anemometers. The ground based
Lidar measurement principle works almost acceptable in flat terrain. In
complex terrain and close to woods the measurement volume is disturbed
because the flow is no longer horizontally homogeneous. These conditions
require special attention and correction methods. Due to the large
measurement volume, ground based Lidars perform a spatial averaging
which has the effect of a low pass filter on turbulence measurements.
Theory and measurements seem to be in good agreement. Lidar
measurements from a rotating spinner have been performed. The analysis
show good perspectives for scanning the incoming wind, which may lead to
better controlled wind turbines. Lidars have also been used to scan the
wake of wind turbines. These measurements document the meandering
The second part of the overview considers power performance
measurements. A new investigation on the influence of wind shear points to
a revision of the definition of a power curve. A new measurement method
has been developed which has a good chance of being implemented in the
present revision of the IEC performance standard. Also, a turbulence
normalization method has been tested but not found efficient enough for
inclusion in the IEC standard. In relation to the coming IEC standard on
performance verification with the use of nacelle anemometry, IEC61400-
12-2-CD, nacelle anemometry has been studied, both with experiments and
in theory. An alternative to nacelle anemometry has been developed, the socalled
spinner anemometer. This type of sensor measures yaw-error with
high absolute accuracy, and avoids the draw-backs of nacelle anemometry
because the spinner anemometer is positioned in front of the rotor.
Advances in classic mast measurement technologies have also been made.
A mast flow distortion correction method has been developed to improve
classical state of the art mast measurements. Finally, an optical method for
measurements of turbine vibrations is considered.
|Series||Denmark. Forskningscenter Risoe. Risoe-R|
- Remote Measurement and measurement technique
, Bingöl, F., Courtney, M.
, Diznabi, B., Foussekis, D., Gottschall, J., ... Wagner, R.
(2011). Advancements in Wind Energy Metrology – UPWIND 1A2.3
. Roskilde: Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi. Denmark. Forskningscenter Risoe. Risoe-R, No. 1752(EN)