In a recently published white paper, consultant Deutsche WindGuard discloses the need for amending and specifying the basics for anemometer classification defined in IEC 61400-12-1. To date it is custom to classify anemometers under the atmospheric ambient conditions of the lab. This does not take into account the operating conditions, especially with regards to air pressure and temperature.
Experiments by Deutsche WindGuard now show that ambient conditions have a much higher influence on the behaviour of sensors than previously assumed. The company built a special pressurised wind tunnel for anemometer classification. In this wind tunnel, they can simulate temperatures ranging from -20° to +40°C and air pressure from 600 hPa to 1.100 hPa. This enables them to reproduce ambient conditions of wind energy sites from the Sahara desert to mountains in the Andes in the lab. The first measurement campaign clearly indicates that the assumptions that are the basis for anemometer classification according to IEC 61400-12-1 are not complete. In the following months, WindGuard – in cooperation with anemometer manufacturers – will conduct further systematic research on staple anemometer types.