BS EN 61400-13:2016
$215.11
Wind turbines – Measurement of mechanical loads
| Published By | Publication Date | Number of Pages |
| BSI | 2016 | 112 |
IEC 61400-13:2015(B) describes the measurement of fundamental structural loads on wind turbines for the purpose of the load simulation model validation. The standard prescribes the requirements and recommendations for site selection, signal selection, data acquisition, calibration, data verification, measurement load cases, capture matrix, post-processing, uncertainty determination and reporting. Informative annexes are also provided to improve understanding of testing methods. This standard replaces IEC TS 61400-13 published in 2001; it constitutes a technical revision and transition from technical specification to International Standard.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | English CONTENTS |
| 12 | FOREWORD |
| 14 | INTRODUCTION |
| 15 | 1 Scope 2 Normative references 3 Terms and definitions |
| 18 | 4 Symbols, units and abbreviations |
| 20 | 5 General 5.1 Document structure |
| 21 | 5.2 Safety during testing 6 Test requirements 6.1 General 6.2 Test site requirements 6.3 Measurement load cases 6.3.1 General |
| 22 | 6.3.2 MLCs during steady-state operation 6.3.3 MLCs during transient events Tables Table 1 – MLCs during steady-state operation related to the DLCs defined in IEC 61400-1 |
| 23 | 6.3.4 MLCs for dynamic characterization Table 2 – Measurement of transient load cases related to the DLCs defined in IEC 61400-1 Table 3 – MLCs for dynamic characterization |
| 24 | 6.3.5 Capture matrices |
| 25 | Table 4 – Capture matrix for normal power production for stall controlled wind turbines |
| 26 | Table 5 – Capture matrix for normal power production for non stall controlled wind turbines Table 6 – Capture matrix for parked condition |
| 27 | 6.4 Quantities to be measured 6.4.1 General 6.4.2 Load quantities Table 7 – Capture matrix for normal transient events Table 8 – Capture matrix for other than normal transient events |
| 28 | Figures Figure 1 – Fundamental wind turbine loads: tower base, rotor and blade loads Table 9 – Wind turbine fundamental load quantities |
| 29 | 6.4.3 Meteorological quantities 6.4.4 Wind turbine operation quantities Table 10 – Additional load quantities for turbines with a rated power output greater than 1 500 kW and rotor diameter greater than 75 m Table 11 – Meteorological quantities |
| 30 | 6.5 Turbine configuration changes Table 12 – Wind turbine operation quantities |
| 31 | 7 Instrumentation 7.1 Load quantities 7.1.1 Types of sensors 7.1.2 Choice of sensor location 7.1.3 Measurement of blade root bending moments |
| 32 | 7.1.4 Blade bending moment distribution 7.1.5 Blade torsion frequency/damping 7.1.6 Measurement of rotor yaw and tilt moment 7.1.7 Measurement of the rotor torque 7.1.8 Measurement of tower base bending 7.1.9 Tower top bending moments |
| 33 | 7.1.10 Tower mid bending moments 7.1.11 Tower torque 7.1.12 Tower top acceleration 7.1.13 Pitch actuation loads (on hub side of pitch bearing) 7.2 Meteorological quantities 7.2.1 Measurement and installation requirements 7.2.2 Icing potential 7.2.3 Atmospheric stability |
| 34 | 7.3 Wind turbine operation quantities 7.3.1 Electrical power 7.3.2 Rotor speed or generator speed 7.3.3 Yaw misalignment 7.3.4 Rotor azimuth angle 7.3.5 Pitch position 7.3.6 Pitch speed 7.3.7 Brake moment 7.3.8 Wind turbine status 7.3.9 Brake status |
| 35 | 7.4 Data acquisition system 7.4.1 General 7.4.2 Resolution 7.4.3 Anti-aliasing 8 Determination of calibration factors 8.1 General |
| 36 | 8.2 Calibration of load channels 8.2.1 General Table 13 – Summary of suitable calibration methods |
| 37 | 8.2.2 Blade bending moments 8.2.3 Main shaft moments |
| 38 | 8.2.4 Tower bending moments 8.2.5 Tower torque |
| 39 | 8.3 Calibration of non-load channels 8.3.1 Pitch angle 8.3.2 Rotor azimuth angle 8.3.3 Yaw angle 8.3.4 Wind direction 8.3.5 Pitch actuation loads |
| 40 | 8.3.6 Brake moment 9 Data verification 9.1 General 9.2 Verification checks 9.2.1 General |
| 41 | 9.2.2 Blade moments |
| 42 | 9.2.3 Main shaft 9.2.4 Tower |
| 43 | 10 Processing of measured data 10.1 General 10.2 Fundamental load quantities 10.3 Load quantities for larger turbines 10.4 Wind speed trend detection |
| 44 | 10.5 Statistics 10.6 Rainflow counting 10.7 Cumulative rainflow spectrum 10.8 Damage equivalent load |
| 45 | 10.9 Wind speed binning |
| 46 | 10.10 Power spectral density 11 Uncertainty estimation 12 Reporting |
| 50 | Annexes Annex A (informative) Example co-ordinate systems A.1 General A.2 Blade co-ordinate system A.3 Hub co-ordinate system Figure A.1 – Blade co-ordinate system |
| 51 | A.4 Nacelle co-ordinate system Figure A.2 – Hub co-ordinate system |
| 52 | A.5 Tower co-ordinate system Figure A.3 – Nacelle co-ordinate system Figure A.4 – Tower co-ordinate system |
| 53 | A.6 Yaw misalignment A.7 Cone angle and tilt angle Figure A.5 – Yaw misalignment Figure A.6 – Cone angle and tilt angle |
| 54 | A.8 Rotor azimuth angle A.9 Blade pitch angle |
| 55 | Annex B (informative) Procedure for the evaluation of uncertainties in load measurements on wind turbines B.1 List of symbols |
| 56 | B.2 General procedure B.2.1 Standard uncertainty |
| 57 | B.2.2 Analytical combination of standard uncertainties |
| 58 | B.2.3 Total uncertainty |
| 59 | B.3 Uncertainties of binned averaged values B.3.1 General B.3.2 Uncertainty of calibration and signal B.3.3 Uncertainty of the bin scatter B.3.4 Uncertainty of the x-axis quantity B.3.5 Uncertainty of bin averaged mean values |
| 60 | B.4 Standard uncertainty of DEL and load spectra B.5 Examples of an uncertainty evaluation B.5.1 Example for analytical shunt calibration of tower torque Table B.1 – Uncertainty components |
| 64 | Table B.2 – Values and uncertainties for the calculation |
| 65 | Figure B.1 – Explanation of used symbols |
| 67 | B.6 Determination and use of calibration matrix B.6.1 Determination of the calibration matrix |
| 68 | B.6.2 Use of the calibration matrix |
| 69 | B.6.3 Time series |
| 71 | Annex C (informative) Sample presentation of mechanical load measurements and analysis C.1 General Figure C.1 – Hub-height wind speed as a function of time |
| 72 | Figure C.2 – Hub-height turbulence intensity as a function of hub-height wind speed Figure C.3 – Turbulence intensity trending as a function of hub-height wind speed |
| 73 | Figure C.4 – Global capture matrix with all loads channels operating |
| 74 | Figure C.5 – IEC example turbine at 9,1 m/s – Wind turbine operational and meteorological quantities |
| 75 | Figure C.6 – IEC example turbine at 9,1 m/s – Major load components |
| 76 | Figure C.7 – 10-minute statistics for blade 1 root edge bending |
| 77 | Figure C.8 – Power spectral density of blade 1 root edge bending |
| 78 | Table C.1 – Binned data for blade 1 root edge bending |
| 79 | Figure C.9 – Cumulative rainflow spectrum forblade 1 root edge bending during test period |
| 80 | Table C.2 – Transient capture matrix for normal start-up and shutdown Table C.3 – Brief statistical description for normal shutdown for IEC example turbine at 9,5 m/s |
| 81 | Figure C.10 – IEC example turbine normal shutdown at 9,5 m/s – Wind turbine operational and meteorological quantities |
| 82 | Figure C.11 – IEC example turbine normal shutdown at 9,5 m/s – Major load components |
| 83 | Annex D (informative) Recommendations for offshore measurements Figure D.1 – Example of wave spectrum and monopile response |
| 84 | Figure D.2 – Example of wave spectrum |
| 85 | Annex E (informative) Load model validation E.1 General |
| 86 | E.2 Methods for loads comparison E.2.1 Statistical binning Figure E.1 – Measured data Figure E.2 – Simulated data Figure E.3 – Comparison of wind speed binned averaged 10 min. statistics |
| 87 | E.2.2 Spectral functions Figure E.4 – Comparison of 1 Hz equivalent loads Figure E.5 – Comparison of 1 Hz equivalent loads (wind speed binned) Figure E.6 – Comparison of PSD functions |
| 88 | E.2.3 Fatigue spectra E.2.4 Point by point Figure E.7 – Comparison of fatigue spectra |
| 89 | Figure E.8 – Point by point comparison of wind speed time histories Figure E.9 – Point by point comparison of load time histories |
| 90 | Annex F (informative) Methods for identification of wind speed trends F.1 List of symbols F.2 General |
| 91 | F.3 Trend identification methods Figure F.1 – Comparison of measured wind speed (vmeas), smoothingfiltered wind speed (vfilt) and resulting trend-free wind speed (vHP) |
| 93 | Figure F.2 – Differences of turbulence intensities calculated with un-filtered and filtered wind speed versus mean measured wind speed |
| 94 | Figure F.3 – Ratio of turbulence intensities calculated with un-filtered and filtered wind speed versus mean measured wind speed |
| 95 | F.4 Ongoing procedure |
| 96 | Annex G (informative) Data acquisition considerations G.1 Data acquisition system G.1.1 General G.1.2 Resolution |
| 97 | G.1.3 Sampling model and filtering Figure G.1 – Anti-aliasing check |
| 98 | Table G.1 – Wind turbine significant frequencies Table G.2 – Sampling ratio |
| 99 | G.1.4 Other considerations |
| 100 | Annex H (informative) Load calibration H.1 General H.2 Gravity load calibration of the blade bending |
| 101 | H.3 Analytical calibration of the tower bending moments |
| 102 | H.4 External load calibration of the rotor torque |
| 103 | Annex I (informative) Temperature drift I.1 General I.2 Known issues Figure I.1 – Observed scatter in the original 10-min average values of the blade edge moment together with the same signal after temperature compensation in dark blue |
| 104 | I.3 Recommendations Figure I.2 – Linear regression through the offsets derived from the different calibration runs |
| 105 | Annex J (informative) Mechanical load measurements on vertical axis wind turbines J.1 General J.2 Terms and definitions J.3 Coordinate systems |
| 106 | J.4 Quantities to be measured J.4.1 Fundamental loads Figure J.1 – Darrieus style VAWT Figure J.2 – Helical Darrieus style VAWT |
| 107 | J.5 Measurements J.5.1 Measurement of blade attachment bending moments J.5.2 Blade mid-span bending moment J.5.3 Blade modal frequency/damping J.5.4 Connecting strut bending moment Table J.1 – Minimum recommendations for VAWT fundamental load quantities |
| 108 | J.5.5 Connecting strut axial force J.5.6 Connecting strut modal frequency/damping J.5.7 Rotor shaft torque J.5.8 Tower normal bending |
| 109 | Bibliography |
