1 Scope
IEC 61400‑50
specifies methods and requirements for the application of instruments to measure
wind speed (and related parameters, e.g. wind direction, turbulence intensity). Such
measurements are required as an input to some of the evaluation and testing procedures
for wind energy and wind turbine technology (e.g. resource evaluation and turbine
performance testing) described by other standards in the IEC 61400 series. This document is applicable specifically to the use of wind measurement instruments
mounted on meteorological masts, turbine nacelles or turbine spinners which measure
the wind at the location at which the instruments are mounted. This document excludes
remote sensing devices which measure the wind at some location distant from the location
at which the instrument is mounted (e.g. vertical profile or forward facing lidars).
This document specifies the following:
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a) the classification parameters for cup and sonic anemometers such that the uncertainty
in wind speed measurement for a specific type and model of anemometer exposed to a
certain class of environmental conditions can be assessed;
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b) the procedure and requirements for classifying cup and sonic anemometers as, for example,
part of the type testing of a specific anemometer model and type;
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c) the procedures and requirements for wind tunnel calibration of anemometers;
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d) an additional or alternative method of checking the consistency of the calibration
of an anemometer in the field by carrying out an in-situ comparison with another anemometer;
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e) the requirements for the mounting of anemometers and other instruments on meteorological
masts;
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f) the assessment of wind speed measurement uncertainty;
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g) reporting requirements.