The 4th and last measurement campaign of the UniTTe project has started in July 2017 in Hill of Towie, Scotland, UK. The purpose of the campaign is to demonstrate how nacelle lidar measurements can benefit power performance testing in complex terrain, with an emphasis on whether or not nacelle lidars could also be used to calibrate a site. The campaign is conducted in collaboration with RES-group.
The UniTTe project aims at providing the scientific basis of the new generation standards for power performance and load testing of electricity producing wind turbines. The vision is to use nacelle lidars to measure the wind conditions closer to the rotor and thereby increase the correlations with power and loads and at the same time decrease the effect of the terrain on the flow.
In collaboration with RES, the Hill Of Towie measurement campaign was commissioned in July 2017. The Hill Of Towie wind farm is located in Scotland. The wind farm comprises 21 Siemens 2.3 MW turbines of 82m rotor diameter (see Google Earth pictures below), in operation since Fall 2011.
The Hill of Towie site has been extensively studied in the past by RES, using conventional met. masts (site calibration) as well as ground-based profiling lidars (ZephIR 300). The original IEC-compliant site calibration occurred in 2011 prior to the installation of the wind turbines. A power curve test of turbine 13 (WTG13) was conducted until 2014; the reference mast was consecutively removed (also compliant with the IEC61400-12-1:ed1 standards).
Within the UniTTe project, the 2017 measurement campaign aims are:
- to develop and demonstrate a new methodology to assess the power performance of wind turbines using nacelle lidars
- to investigate the possibility of using nacelle lidar measurements to conduct site calibrations
The measurement of the power curve of WTG13 will be performed in two ways:
- Using a ground-based profiling lidar of type ZephIR300, following the procedures of the IEC 61400-12-1:2017 standards
- Using nacelle lidar systems.
In June and July 2017, two nacelle lidars were installed on turbine 13: one 4-beam Wind Iris lidar from Avent Lidar Technology (bottom in picture below) and one ZephIR Dual Mode lidar (top in picture below; unit owned and provided by Siemens Wind Power). Measurements data will be collected until end of September 2017.
Different techniques to perform power performance testing in complex terrain using nacelle lidars are currently being developed and tested using the experimental data. Comparisons with the ground-based ZephIR300 lidar measurements and results of power curve measurements will be compiled in a detailed report during Fall 2017.