UNE-EN IEC 61400-12:2024

42 The IEC 61400 series of standards addresses wind energy generation technical requirements up to43 the point of interconnection with the utility grid system. Part 12 of the IEC 61400 series of standards44 comprises a sub-set of standards which are to be used in the evaluation and measurement of the45 power performance characteristics of wind turbines. The power performance characterisation of wind46 turbines of all types and sizes is covered.47 Wind turbine power performance characteristics are determined from a measured power curve and48 an associated estimated annual energy production (AEP) and its uncertainty. The measured power49 curve, defined as the relationship between the wind speed and the wind turbine power output, is50 determined by collecting simultaneous measurements of meteorological variables (including wind51 speed), as well as wind turbine signals (including power output) at the test site for a period that is52 long enough to establish a statistically significant database over a range of wind speeds and under53 varying wind and atmospheric conditions. The AEP is calculated by applying the measured power54 curve to reference wind speed frequency distributions, assuming 100 % availability.55 Part 12-0 provides a general introduction to the available options for power performance56 measurement and the contributing evaluations which are further detailed in the other parts of the IEC57 61400-12 series. Although the -12 series also defines the specifications of the meteorological58 variables (and in particular wind speed) required for the power performance evaluation, the methods59 and procedures for measuring or otherwise acquiring the wind speed data are defined in the IEC60 61400-50 wind measurement series of standards.61 The evaluation of the wind turbine power performance characteristic according to this series of62 standards requires the measured power curve and derived energy production figures to be63 supplemented by an assessment of uncertainty sources and their combined effects. The basis of the64 uncertainty assessment is ISO/IEC Guide 98-3. The wind measurement uncertainty sources shall be65 identified and quantified from procedures described in the relevant wind measurement standards66 contained in the IEC 61400-50 series. The wind measurement uncertainties shall be propagated67 through to and combined with the other sources of uncertainty in the power curve and annual energy68 production using methods and assumptions described in the IEC 61400-12 series of standards.