Objective

In the round robin the participants will analyse a dataset of nacelle lidar measurements from an offshore turbine. The objective is to reconstruct the wind field in the induction zone upstream of the turbine by using wind speed measurements at multiple ranges. From the reconstructed wind field the participants will derive the freestream wind speed. By establishing the freestream wind speed the community will get a better sense of the influence of induction on topics such as power curve verification, wind turbine power performance and wind farm power performance.
The participants will work independently on analysis of the common dataset. The round robin will be concluded with a workshop, where the methods and results of the analyses will be presented.

Expected outcome

At the concluding workshop the participants will present their wind field reconstruction method and results. The workshop will discuss the pros and cons of the different methods and recommend the necessary steps towards a standard method for reconstructing the wind field in the induction zone from nacelle lidar measurements.

The outcome of the round robin will be

1. An exchange of experience in wind field reconstruction techniques
2. Creating links between the potential users and the researchers
3. A set of collected results presented at the concluding workshop
4. A list of barriers and possible solutions to the adoption of the techniques. After the workshop a working group will be initiated to write a common paper of the results and submit it to a conference

Schedule

The proposed schedule for the round robin is detailed below:

• The registration deadline is June 15. Data will made available shortly after the registration on this website.
• Three conference calls are planned to take place in July, August, and September.
• First results will be due on September 15.
• The workshop is planned to take place in the first two weeks for October. The venue will be most likely be at Ørsted, Copenhagen. The workshop date will be agreed by the end of June among the registered participants.

Outline of the work

The participants will work with nacelle lidar measurements averaged over ten minutes. The lidar data have been cleaned and contain only periods where the turbine is operating normally and neither the turbine nor the lidar beams are affected by wakes. Based on a wind field model of their choice, the participants will reconstruct the wind field in the induction zone and obtain an estimate of the freestream wind speed far upstream of the turbine.

The reconstructed wind field results will be sent to the workshop leader in a template provided along with the data and the round robin instructions. Participants are to provide some details of the analysis with the results submitted to the round robin leader.

Prior to the workshop the round robin leader will collect results from the participants and provide feedback on the results in an anonymized format.

Practical arrangements

Registration

Please register at the latest by 15 June 2018 by contacting the organisers. Upon registration, the participants will receive a set of instructions for participating in the round robin. Participation in the round robin is not a commitment to attend the workshop. An invitation and details for the workshop will be provided at a later date. Attendance at the workshop does not require active participation in the round robin exercise.

Contact Information

Please contact Nicolai Gayle Nygaard (round robin leader) with any questions you may have about the round robin and  David Schlipf (IEA Wind Task 32 Operating Agent) for all Task 32 related questions.

Expected participants

The round robin is open to anyone interested in participating. The participants will likely come from the following groups:

• Academics
• Consultants
• Lidar manufacturers
• Turbine manufacturers
• Wind farm developers
• Wind farm operators
• Other lidar end users.