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BS EN 61400-12-1:2017

BS EN 61400-12-1:2017

$256.21

Wind energy generation systems – Power performance measurements of electricity producing wind turbines

Published By Publication Date Number of Pages
BSI 2017 268
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PDF Catalog

PDF Pages PDF Title
2 National foreword
7 English
CONTENTS
18 FOREWORD
20 INTRODUCTION
21 1 Scope
2 Normative references
22 3 Terms and definitions
25 4 Symbols and units
28 5 Power performance method overview
31 Tables
Table 1 – Overview of wind measurement configurations for powercurve measurements that meet the requirements of this standard
32 6 Preparation for performance test
6.1 General
6.2 Wind turbine and electrical connection
6.3 Test site
6.3.1 General
6.3.2 Location of the wind measurement equipment
33 6.3.3 Measurement sector
6.3.4 Correction factors and uncertainty due to flow distortion originating from topography
Figures
Figure 1 – Requirements as to distance of the wind measurement equipment and maximum allowed measurement sectors
34 7 Test equipment
7.1 Electric power
7.2 Wind speed
7.2.1 General
35 7.2.2 General requirements for meteorological mast mounted anemometers
Table 2 – Wind speed measurement configurations (X indicates allowable configuration)
36 7.2.3 Top-mounted anemometers
7.2.4 Side-mounted anemometers
7.2.5 Remote sensing device (RSD)
37 7.2.6 Rotor equivalent wind speed measurement
7.2.7 Hub height wind speed measurement
7.2.8 Wind shear measurements
38 Figure 2 – Wind shear measurement heights appropriate to measurement of rotor equivalent wind speed
39 7.3 Wind direction
7.4 Air density
Figure 3 – Wind shear measurement heights when no wind speed measurementsabove hub height are available (for wind shear exponent determination only)
40 7.5 Rotational speed and pitch angle
7.6 Blade condition
7.7 Wind turbine control system
7.8 Data acquisition system
8 Measurement procedure
8.1 General
8.2 Wind turbine operation
41 8.3 Data collection
8.4 Data rejection
42 8.5 Database
9 Derived results
9.1 Data normalisation
9.1.1 General
43 9.1.2 Correction for meteorological mast flow distortion of side-mounted anemometer
9.1.3 Wind shear correction (when REWS measurements available)
Figure 4 – Process of application of the various normalisations
45 Table 3 – Example of REWS calculation
46 9.1.4 Wind veer correction
9.1.5 Air density normalisation
47 9.1.6 Turbulence normalisation
9.2 Determination of the measured power curve
48 9.3 Annual energy production (AEP)
50 9.4 Power coefficient
10 Reporting format
53 Figure 5 – Presentation of example database: power performance test scatter plot sampled at 1 Hz (mean values averaged over 10 min)
54 Figure 6 – Presentation of example measured power curve
Figure 7 – Presentation of example CP curve
55 Table 4 – Example of presentation of a measured power curve
56 Table 5 – Example of presentation of estimated annual energy production
57 Annexes
Annex A (normative) Assessment of influences caused by wind turbines and obstacles at the test site
A.1 General
A.2 Requirements regarding neighbouring and operating wind turbines
58 A.3 Requirements regarding obstacles
A.4 Method for calculation of sectors to exclude
Table A.1 – Obstacle requirements: relevance of obstacles
60 Figure A.1 – Sectors to exclude due to wakes of neighbouring and operating wind turbines and significant obstacles
61 Figure A.2 – An example of sectors to exclude due to wakes of the wind turbine under test, a neighbouring and operating wind turbine and a significant obstacle
62 A.5 Special requirements for extended obstacles
63 Annex B (normative) Assessment of terrain at the test site
Figure B.1 – Illustration of area to be assessed, top view
64 Figure B.2 – Example of determination of slope and terrain variation from the best-fit plane: “2L to 4L” and the case “measurement sector” (Table B.1, line 2)
Table B.1 – Test site requirements: topographical variations
65 Figure B.3 – Determination of slope for the distance “2L to 4L” and “8L to 16L”and the case “outside measurement sector” (Table B.1, line 3 and line 5)
66 Annex C (normative) Site calibration procedure
C.1 General
C.2 Overview of the procedure
67 Figure C.1 – Site calibration flow chart
68 C.3 Test set-up
C.3.1 Considerations for selection of the test wind turbine and location of the meteorological mast
69 Figure C.2 – Terrain types
70 C.3.2 Instrumentation
C.4 Data acquisition and rejection criteria
71 C.5 Analysis
C.5.1 Assessment of site shear conditions
73 C.5.2 Method 1: Bins of wind direction and wind shear
74 C.5.3 Method 2: Linear regression method where shear is not a significant influence
C.5.4 Additional calculations
75 C.6 Site calibration uncertainty
C.6.1 Site calibration category A uncertainty
77 C.6.2 Site calibration category B uncertainty
C.6.3 Combined uncertainty
C.7 Quality checks and additional uncertainties
C.7.1 Convergence check
78 C.7.2 Correlation check for linear regression (see C.5.3)
C.7.3 Change in correction between adjacent wind direction bins
C.7.4 Removal of the wind direction sensor between site calibration and power performance test
79 C.7.5 Site calibration and power performance measurements in different seasons
80 C.8 Verification of results
81 C.9 Site calibration examples
C.9.1 Example A
Figure C.3 – Example of the results of a verification test
82 Figure C.4 – Wind shear exponent vs. time of day, example A
83 Figure C.5 – Wind shear exponents at wind turbine location vs. reference meteorological mast, example A where the colour axis = wind speed (m/s)
84 Figure C.6 – Wind speed ratios and number of data points vs. wind shear exponent and wind direction bin – wind speed ratios (full lines), number of data points (dotted lines)
85 Table C.1 – Site calibration flow corrections (wind speed ratio)
Table C.2 – Site calibration data count
86 C.9.2 Example B
Figure C.7 – Data convergence check for 190° bin
87 Figure C.8 – Wind shear exponent vs. time of day, example B
Figure C.9 – Wind shear exponents at wind turbine location vs. reference meteorological mast, example B
88 Figure C.10 – Linear regression of wind turbine location vs. reference meteorological mast hub height wind speeds for 330° bin
Figure C.11 – Wind speed ratios vs. wind speed for the 330° bin
89 Figure C.12 – Wind speed ratios vs. wind shear for the 330° bin
90 Figure C.13 – Wind shear exponents at wind turbine location vs. reference meteorological mast post-filtering
Figure C.14 – Linear regression of wind turbine location vs. reference meteorological mast hub height wind speeds for 330° bin, post-filtering
91 Figure C.15 – Wind speed ratios vs. wind speed for the 330° bin, post-filtering
92 Figure C.16 – Data convergence check for 330° bin
Table C.3 – r2 values for each wind direction bin
Table C.4 – Additional uncertainty due to change in bins
93 C.9.3 Example C
Figure C.17 – Site calibration wind shear vs. power curve test wind shear
95 Figure C.18 – Convergence check for 270° bin
Table C.5 – Additional uncertainty due to change in bins
96 Annex D (normative) Evaluation of uncertainty in measurement
Table D.1 – List of uncertainty components
99 Annex E (informative) Theoretical basis for determining the uncertainty of measurement using the method of bins
E.1 General
E.2 Combining uncertainties
E.2.1 General
101 E.2.2 Expanded uncertainty
Table E.1 – Expanded uncertainties
102 E.2.3 Basis for the uncertainty assessment
103 Table E.2 – List of category A and B uncertainties
105 E.3 Category A uncertainties
E.3.1 General
E.3.2 Category A uncertainty in electric power
106 E.3.3 Category A uncertainties in the site calibration
E.4 Category B uncertainties: Introduction and data acquisition system
E.4.1 Category B uncertainties: Introduction
107 E.4.2 Category B uncertainties: data acquisition system
E.5 Category B uncertainties: Power output
E.5.1 General
E.5.2 Category B uncertainties: Power output – Current transformers
108 E.5.3 Category B uncertainties: Power output – Voltage transformers
109 E.5.4 Category B uncertainties: Power Output – Power transducer or other power measurement device
E.5.5 Category B uncertainties: Power output – Data acquisition
E.6 Category B uncertainties: Wind speed – Introduction and sensors
E.6.1 Category B uncertainties: Wind speed – Introduction
E.6.2 Category B uncertainties: Wind speed – Hardware
110 E.6.3 Category B uncertainties: Wind speed – Meteorological mast mounted sensors
113 E.7 Category B uncertainties: Wind speed – RSD
E.7.1 General
E.7.2 Category B uncertainties: Wind speed – RSD – Calibration
E.7.3 Category B uncertainties: Wind speed – RSD – in-situ check
E.7.4 Category B uncertainties: Wind speed – RSD – Classification
115 E.7.5 Category B uncertainties: Wind speed – RSD – Mounting
E.7.6 Category B uncertainties: Wind speed – RSD – Flow variation
116 E.7.7 Category B uncertainties: Wind speed – RSD – Monitoring test
117 E.8 Category B uncertainties: Wind speed – REWS
E.8.1 General
E.8.2 Category B uncertainties: Wind speed – REWS – Wind speed measurement over whole rotor
118 E.8.3 Category B uncertainties: Wind speed – REWS – Wind veer
E.9 Category B uncertainties: Wind speed – Terrain
E.9.1 General
119 E.9.2 Category B uncertainties: Wind speed – Terrain – Pre-calibration
E.9.3 Category B uncertainties: Wind speed – Terrain – Post-calibration
120 E.9.4 Category B uncertainties: Wind speed – Terrain – Classification
121 E.9.5 Category B uncertainties: Wind speed – Terrain – Mounting
E.9.6 Category B uncertainties: Wind speed – Terrain – Lightning finial
122 E.9.7 Category B uncertainties: Wind speed – Terrain – Data acquisition
E.9.8 Category B uncertainties: Wind speed – Terrain – Change in correction between adjacent bins
E.9.9 Category B uncertainties: Wind speed – Terrain – Removal of WD sensor
E.9.10 Category B uncertainties: Wind speed – Terrain – Seasonal variation
123 E.10 Category B uncertainties: Air density
E.10.1 General
E.10.2 Category B uncertainties: Air density – Temperature introduction
124 E.10.3 Category B uncertainties: Air density – Temperature – Calibration
E.10.4 Category B uncertainties: Air density – Temperature – Radiation shielding
E.10.5 Category B uncertainties: Air density – Temperature – Mounting
E.10.6 Category B uncertainties: Air density – Temperature – Data acquisition
125 E.10.7 Category B uncertainties: Air density – Pressure introduction
E.10.8 Category B uncertainties: Air density – Pressure – Calibration
126 E.10.9 Category B uncertainties: Air density – Pressure – Mounting
E.10.10 Category B uncertainties: Air density – Pressure – Data acquisition
E.10.11 Category B uncertainties: Air density – Relative humidity introduction
127 E.10.12 Category B uncertainties: Air density – Relative humidity – Calibration
E.10.13 Category B uncertainties: Air density – Relative humidity – Mounting
E.10.14 Category B uncertainties: Air Density – Relative humidity – Data acquisition
E.10.15 Category B uncertainties: Air density – Correction
128 E.11 Category B uncertainties: Method
E.11.1 General
E.11.2 Category B uncertainties: Method – Wind conditions
130 Table E.3 – Example of standard uncertainties due to absence of a wind shear measurement
132 Table E.4 – Example of standard uncertainties due to absence of a wind veer measurement
133 E.11.3 Category B uncertainties: Method – Seasonal effects
Table E.5 – Uncertainty contributions due to lack of upflow knowledge
Table E.6 – Uncertainty contributions due to lack of turbulence knowledge
134 E.11.4 Category B uncertainties: Method – Turbulence normalisation (or the lack thereof)
E.11.5 Category B uncertainties: Method – Cold climate
135 E.12 Category B uncertainties: Wind direction
E.12.1 General
E.12.2 Category B uncertainties: Wind direction – Vane or sonic
137 E.12.3 Category B uncertainties: Wind direction – RSD
138 E.13 Combining uncertainties
E.13.1 General
E.13.2 Combining Category B uncertainties in electric power (uP,i)
E.13.3 Combining uncertainties in the wind speed measurement (uV,i)
E.13.4 Combining uncertainties in the wind speed measurement from cup or sonic (uVS,i)
139 E.13.5 Combining uncertainties in the wind speed measurement from RSD (uVR,i)
E.13.6 Combining uncertainties in the wind speed measurement from REWS uREWS,i
140 E.13.7 Combining uncertainties in the wind speed measurement for REWS for either a meteorological mast significantly above hub height or an RSD with a lower-than-hub-height meteorological mast
142 Table E.7 – Suggested assumptions for correlations of measurement uncertainties between different measurement heights
143 E.13.8 Combining uncertainties in the wind speed measurement for REWS for a hub height meteorological mast + RSD for shear using an absolute wind speed
144 E.13.9 Combining uncertainties in the wind speed measurement for REWS for a hub height meteorological mast and RSD for shear using a relative wind speed
146 E.13.10 Combining uncertainties in the wind speed measurement from REWS due to wind veer across the whole rotor uREWS,veer,i
148 Table E.8 – Suggested correlation assumptions for relative wind direction measurement uncertainties at different measurement heights
149 E.13.11 Combining uncertainties in the wind speed measurement from flow distortion due to site calibration uVT,i
150 E.13.12 Combining uncertainties for the temperature measurement uT,i
151 E.13.13 Combining uncertainties for the pressure measurement uB,i
E.13.14 Combining uncertainties for the humidity measurement uRH,i
152 E.13.15 Combining uncertainties for the method related components uM,i
E.13.16 Combining uncertainties for the wind direction measurement with wind vane or sonic anemometer uWV,i
E.13.17 Combining uncertainties for the wind direction measurement with RSD uWR,i
153 E.13.18 Combined category B uncertainties
E.13.19 Combined standard uncertainty – Power curve
E.13.20 Combined standard uncertainty – Energy production
E.14 Relevance of uncertainty components under specified conditions
154 E.15 Reference tables
Table E.9 – Uncertainties from air density normalisation
156 Table E.10 – Sensitivity factors
157 Table E.11 – Category B uncertainties
158 Annex F (normative) Wind tunnel calibration procedure for anemometers
F.1 General requirements
F.2 Requirements to the wind tunnel
159 Figure F.1 – Definition of volume for flow uniformity test –The volume will also extend 1,5 x b in depth (along the flow)
160 F.3 Instrumentation and calibration set-up requirements
F.4 Calibration procedure
F.4.1 General procedure cup and sonic anemometers
161 F.4.2 Procedure for the calibration of sonic anemometers
F.4.3 Determination of the wind speed at the anemometer position
162 F.5 Data analysis
F.6 Uncertainty analysis
163 F.7 Reporting format
164 F.8 Example uncertainty calculation
Table F.1 – Example of evaluation of anemometer calibration uncertainty
167 Annex G (normative) Mounting of instruments on the meteorological mast
G.1 General
G.2 Single top-mounted anemometer
169 G.3 Side-by-side top-mounted anemometers
Figure G.1 – Example of a top-mounted anemometer and requirements for mounting
171 G.4 Side-mounted instruments
G.4.1 General
Figure G.2 – Example of alternative top-mounted primary and control anemometers positioned side-by-side and wind vane and other instruments on the boom
172 G.4.2 Tubular meteorological masts
173 Figure G.3 – Iso-speed plot of local flow speed around a cylindrical meteorological mast
174 G.4.3 Lattice meteorological masts
Figure G.4 – Centreline relative wind speed as a function of distance Rd from the centre of a tubular meteorological mast and meteorological mast diameter d
Figure G.5 – Representation of a three-legged lattice meteorological mast
175 Figure G.6 – Iso-speed plot of local flow speed around a triangular lattice meteorological mast with a CT of 0,5
176 Figure G.7 – Centreline relative wind speed as a function of distance Rd from the centre of a triangular lattice meteorological mast of leg distance Lm for various CT values
Table G.1 – Estimation method for CT for various types of lattice mast
178 Figure G.8 – 3D CFD derived flow distortion for two different wind directions around a triangular lattice meteorological mast (CT = 0,27) – For flow direction see the red arrow lower left in each figure
179 G.5 Lightning protection
G.6 Mounting of other meteorological instruments
180 Annex H (normative) Power performance testing of small wind turbines
H.1 General
H.2 Definitions
H.3 Wind turbine system definition and installation
181 H.4 Meteorological mast location
182 H.5 Test equipment
H.6 Measurement procedure
Figure H.1 – Definition of hub height and meteorologicalmast location for vertical axis wind turbines
183 H.7 Derived results
Table H.1 – Battery bank voltage settings
184 H.8 Reporting
H.9 Annex A – Assessment of influence cause by wind turbines and obstacles at the test site
H.10 Annex B – Assessment of terrain at test site
H.11 Annex C – Site calibration procedure
185 Annex I (normative) Classification of cup and sonic anemometry
I.1 General
I.2 Classification classes
186 I.3 Influence parameter ranges
I.4 Classification of cup and sonic anemometers
187 Table I.1 – Influence parameter ranges (10 min averages) of Classes A, B, C, D and S
188 I.5 Reporting format
189 Annex J (normative) Assessment of cup and sonic anemometry
J.1 General
J.2 Measurements of anemometer characteristics
J.2.1 Measurements in a wind tunnel for tilt angular response characteristics of cup anemometers
190 J.2.2 Wind tunnel measurements of directional characteristics of cup anemometers
Figure J.1 – Tilt angular response of a cup anemometer as function of flow angle compared to cosine response
191 J.2.3 Wind tunnel measurements of cup anemometer rotor torque characteristics
J.2.4 Wind tunnel measurements of step responses of cup anemometers
Figure J.2 – Wind tunnel torque measurements QA – QF as function of angular speed of a cup anemometer rotor at 8 m/s
192 J.2.5 Measurement of temperature induced effects on anemometer performance
193 Figure J.3 – Example of bearing friction torque QF as function of temperature for a range of angular speeds
194 J.2.6 Wind tunnel measurements of directional characteristics of sonic anemometers
J.3 A cup anemometer classification method based on wind tunnel and laboratory tests and cup anemometer modelling
J.3.1 Method
J.3.2 Example of a cup anemometer model
196 Figure J.4 – Example of rotor torque coefficient CQA as function of speed ratio �� derived from step responses with Klow equal to –5,5 and Khigh equal to –6,5
198 Table J.1 – Tilt angle response of example cup anemometer
199 Table J.2 – Friction coefficients of example cup anemometer
Table J.3 – Miscellaneous data related to classification of example cup anemometer
200 Figure J.5 – Classification deviations of example cup anemometer showing a class 1,69A (upper) and a class 6,56B (lower)
201 J.4 A sonic anemometer classification method based on wind tunnel tests and sonic anemometer modelling
Figure J.6 – Classification deviations of example cup anemometer showing a class 8,01C (upper) and a class 9,94D (lower)
202 J.5 Free field comparison measurements
203 Annex K (normative) In-situ comparison of anemometers
K.1 General
K.2 Prerequisite
K.3 Analysis method
204 K.4 Evaluation criteria
205 Figure K.1 – Example with triangular lattice meteorological mast
206 Figure K.2 – Example with tubular meteorological mast
207 Annex L (normative) The application of remote sensing technology
L.1 General
208 L.2 Classification of remote sensing devices
L.2.1 General
L.2.2 Data acquisition
209 L.2.3 Data preparation
210 L.2.4 Principle and requirements of a sensitivity test
212 Figure L.1 – Deviation vs upflow angle determined for a remote sensing device with respect to the cup anemometer in Figure J.1
213 Table L.1 – Bin width example for a list of environmental variables
214 Figure L.2 – Example of sensitivity analysis against wind shear
215 Table L.2 – Parameters derived from a sensitivity analysis of a remote sensing device
216 L.2.5 Assessment of environmental variable significance
Table L.3 – Ranges of environmental parameters for sensitivity analysis
217 L.2.6 Assessment of interdependency between environmental variables
Table L.4 – Example selection of environmentalvariables found to have a significant influence
218 Figure L.3 – Example of wind shear versus turbulence intensity
Figure L.4 – Example of percentage deviation of remote sensing device and reference sensor measurements versus turbulence intensity
219 L.2.7 Calculation of accuracy class
Table L.5 – Sensitivity analysis parameters remaining after analysis of interdependency of variables
220 Table L.6 – Example scheme for calculating maximum influence of environmental variables
221 L.2.8 Acceptance criteria
Table L.7 – Preliminary accuracy classes of a remote sensing device considering both all and only the most significant influential variables
Table L.8 – Example final accuracy classes of a remote sensing device
222 L.2.9 Classification of RSD
L.3 Verification of the performance of remote sensing devices
224 Figure L.5 – Comparison of 10 minute averages of the horizontal wind speed component as measured by a remote sensing device and a cup anemometer
Figure L.6 – Bin-wise comparison of measurement of the horizontal wind speed component of a remote sensing device and a cup anemometer
225 L.4 Evaluation of uncertainty of measurements of remote sensing devices
L.4.1 General
L.4.2 Reference uncertainty
L.4.3 Uncertainty resulting from the RSD calibration test
226 Table L.9 – Example of uncertainty calculations arising from calibration of a remote sensing device (RSD) in terms of systematic uncertainties
227 L.4.4 Uncertainty due to remote sensing device classification
228 L.4.5 Uncertainty due to non-homogenous flow within the measurement volume
L.4.6 Uncertainty due to mounting effects
L.4.7 Uncertainty due to variation in flow across the site
229 L.5 Additional checks
L.5.1 Monitoring the performance of the remote sensing device at the application site
L.5.2 Identification of malfunctioning of the remote sensing device
L.5.3 Consistency check of the assessment of the remote sensing device systematic uncertainties
230 L.5.4 In-situ test of the remote sensing device
L.6 Other requirements specific to power curve testing
231 Figure L.7 – Example of permitted range of locations for measurement volume
232 L.7 Reporting
L.7.1 Common reporting on classification test, calibration test, and monitoring of the remote sensing device during application
L.7.2 Additional reporting on classification test
233 L.7.3 Additional reporting on calibration test
L.7.4 Additional reporting on application
234 Annex M (informative) Normalisation of power curve data according to the turbulence intensity
M.1 General
M.2 Turbulence normalisation procedure
235 Figure M.1 – Process for obtaining a power curvefor a specific turbulence intensity (Ireference)
236 M.3 Determination of the zero turbulence power curve
237 Figure M.2 – Process for obtaining the initial zero turbulence power curve parameters from the measured data
Figure M.3 – First approach for initial zero turbulence power curve
239 Figure M.4 – Process for obtaining the theoretical zero-turbulencepower curve from the measured data
240 Figure M.5 – Adjusted initial zero turbulence powercurve (green) compared to first approach (red)
Figure M.6 – Process for obtaining the final zero-turbulence power curve from the measured data
241 M.4 Order of wind shear correction (normalisation) and turbulence normalisation
M.5 Uncertainty of turbulence normalisation or of power curves due to turbulence effects
Figure M.7 – Adjusted initial zero turbulence power curve (green) compared to final zero turbulence power curve (black)
243 Annex N (informative) Wind tunnel calibration procedure for wind direction sensors
N.1 General
N.2 General requirements
N.3 Requirements of the wind tunnel
244 N.4 Instrumentation and calibration set-up requirements
245 N.5 Calibration procedure
Figure N.1 – Example of calibration setup of a wind direction sensor in a wind tunnel
246 N.6 Data analysis
N.7 Uncertainty analysis
N.8 Reporting format
248 N.9 Example of uncertainty calculation
N.9.1 General
N.9.2 Measurement uncertainties generated by determination of the flow direction in the wind tunnel
249 N.9.3 Contribution to measurement uncertainty by the wind direction sensor
250 N.9.4 Result of the uncertainty calculation
251 Table N.1 – Uncertainty contributions in wind directions sensor calibration
252 Table N.2 – Uncertainty contributions and totalstandard uncertainty in wind direction sensor calibration
253 Annex O (informative) Power performance testing in cold climate
O.1 General
O.2 Recommendations
O.2.1 General
O.2.2 Sonic anemometers
O.2.3 Cup anemometers
254 O.3 Uncertainties
O.4 Reporting
255 Annex P (informative) Wind shear normalisation procedure
P.1 General
257 Annex Q (informative) Definition of the rotor equivalent wind speed under consideration of wind veer
Q.1 General
Figure Q.1 – Wind profiles measured with LIDAR over flat terrain
258 Q.2 Definition of rotor equivalent wind speed under consideration of wind veer
Q.3 Measurement of wind veer
Q.4 Combined wind shear and wind veer normalisation
259 Annex R (informative) Uncertainty considerations for tests on multiple turbines
R.1 General
260 Table R.1 – List of correlated uncertainty components
263 Annex S (informative) Mast flow distortion correction for lattice masts
Figure S.1 – Example of mast flow distortion
265 Figure S.2 – Flow distortion residuals versus direction
266 Bibliography

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BS EN 61400-12-1:2017
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