Recommendation for re-working IEC 61400-12-2 methods for the use of spinner anemometry. PTP Deliverable D8.3

Spinner anemometry is used to measure traceable and calibrated wind speed, yaw misalignment and inflow angle. Free wind speed may be estimated by application of a spinner wind speed transfer function on the spinner anemometer measurements. The latter are used in power performance measurements according to the standard IEC 61400-12-2 on use of nacelle anemometry. This document presents recommendations to adapt the standard’s methods; these adaptations are required due to the differences between the spinner and nacelle anemometry, which consists typically of a cup or sonic anemometer mounted on the nacelle behind the rotor.

The suggested method changes are grouped in the following categories:
• Test site and terrain
• Calibrations
• Spinner Transfer Function
• Mounting
• Reporting

Recommendations specific to wind speed uncertainty assessment were provided in a separate report, as required in the project description.

These recommendations are based on the experience gained from the PTP in several wind farms in different terrain types (offshore, flat and complex terrain).