IEC 61400-13:2015/AMD1:2021

IEC 61400-13 ®
Edition 1.0 2021-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
A MENDMENT 1
AM ENDEMENT 1
Wind turbines –
Part 13: Measurement of mechanical loads

Éoliennes –
Partie 13: Mesurage des charges mécaniques

IEC 61400-13:2015-12/AMD1:2021-12(en-fr)

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IEC 61400-13 ®
Edition 1.0 2021-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
A MENDMENT 1
AM ENDEMENT 1
Wind turbines –
Part 13: Measurement of mechanical loads

Éoliennes –
Partie 13: Mesurage des charges mécaniques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.180 ISBN 978-2-8322-1054-3

– 2 – IEC 61400-13:2015/AMD1:2021
© IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WIND TURBINES –
Part 13: Measurement of mechanical loads

AMENDMENT 1
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
This amendment has been prepared by IEC technical committee 88: Wind energy generation
systems.
The text of this amendment is based on the following documents:
Draft Report on voting
88/795/CDV 88/821/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Amendment is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

© IEC 2021
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications/.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 4 – IEC 61400-13:2015/AMD1:2021
© IEC 2021
INTRODUCTION
This amendment to IEC 61400-13:2015 addresses the errors found in Annex B which impact a
significant portion of that annex.

© IEC 2021
Annex B
(informative)
Procedure for the evaluation of uncertainties
in load measurements on wind turbines
B.2.3 Total uncertainty
B.2.3.3 Total uncertainty
Replace Equation (B.7) with the following new equation:
(B.7)
uu+ u
t cal sig
B.3 Uncertainties of binned averaged values
B.3.3 Uncertainty of the bin scatter
Replace Equation (B.8) with the following new equation:
u = stdev / N (B.8)
scat sig
B.3.4 Uncertainty of the x-axis quantity
Replace Equation (B.9) with the following new equation:
y - y
ii-1
uu ×
(B.9)
x x,i
xx-
ii-1
B.3.5 Uncertainty of bin averaged mean values
Replace Equation (B.10) with the following new equation:
22 2
(B.10)
U = uu++ u
mean t scat x
B.5 Examples of an uncertainty evaluation
B.5.1 Example for analytical shunt calibration of tower torque
B.5.1.1 Uncertainty components
Replace Table B.1 with the following table:
=
=
– 6 – IEC 61400-13:2015/AMD1:2021
© IEC 2021
Table B.1 – Uncertainty components
Quantity Symbol Uncertainty Unit Source of Category Distribution Comment
information
Material parameters, cross section geometry and gauges factor in an installation
Gauges 1 % Datasheet B Gaussian –
u
k
factor
Misalignment 3 ° Estimation B Rectangular –
u
F
sens
Diameter at 2,5 mm Estimation B Gaussian –
u
D
i
cross section
Wall 0,1 mm Estimation B Gaussian –
u
T
w
thickness at
cross section
Young 5 % Estimation B Gaussian –
u
E
modulus
Poisson ratio 5 % Estimation B Gaussian –
u
ν
Amplifier calibration
Amplifier and 0,1 % Datasheet / B Gaussian Measurement
u
sig
gain
measurement Calibration value
uncertainty certificate
concerning
gain
Amplifier and 0,1 % Datasheet / B Rectangular Upper value
u
sig
offset
measurement Calibration of the
uncertainty measurement
certificate
concerning range 10 V
offset
Quantization ≈0,3 mV Datasheet B Rectangular 16 Bit A/D
u
Q
resolution converter,
measurement
(Offset)
range ±10 V
Calibration Datasheet / Value shunt
0,1 % B Gaussian
u
R
SH
device Calibration resistant
certificate
Gauges 1 % Datasheet B Gaussian
u
R
SG
resistance
Signal uncertainty
Signal  Tests, A Gaussian Evaluation
s
i
uncertainty statistics, according to
estimations B.2.3.2
B.5.1.2 Calibration uncertainty of an analytical calibration
Replace Equation (B.11) with the following new equation:
M= G ×SM××ε 2
(B.11)
t
Replace Equation (B.13) with the following new equation:
U
o
M=G× SM××
(B.13)
t
kU
i
© IEC 2021
Replace Equation (B.14) with the following new equation:
2 U
o
G × SM × ×
t
kU
i
SS× (B.14)
M V
ΔS
shunt
Replace Equation (B.16) with the following new equation:
2 U
o
G × SM × × × F
t sens
kU
i
SS× (B.16)
MV
ΔS
shunt
Replace Equation (B.18) with the following new equation:
12 U
o
× SM × ×
t
21×+ v kU
∂S ( )
i
M
× S (B.18)
V
∂E ΔS
shunt
Replace Equation (B.19) with the following new equation:
-1 2 U
o
E × SM × × ×
t
kU
21×+ v i
( )
∂S
M
× S
(B.19)
V
∂vSΔ
shunt
Replace Equation (B.20) with the following new equation:
2 U
o
G × ×
∂S kU
M i
× S (B.20)
V
∂SM ΔS
t shunt
Replace the existing text "This lead" at the beginning of the sentence above Equation (B.22)
with "This leads".
Replace Equation (B.22) with the following new equation:
2 U
o
G ××SM
t
∂S kU
Mi
× S (B.22)
V
∂DSΔ
i shunt
Replace Equation (B.23) with the following new equation:
2 U
o
G ××SM
t
∂S kU
M i
× S (B.23)
V
∂TSΔ
W shunt
=
=
=
=
=
=
=
– 8 – IEC 61400-13:2015/AMD1:2021
© IEC 2021
Replace Equation (B.24) with the following new equation:
-2 U
o
G × SM × ×
t
∂SU
k
Mi
× S (B.24)
V
∂k ΔS
shunt
Replace Equation (B.25) with the following new equation:
2 U
o
G × SM × ×
t
∂S kU
Mi
(B.25)
× S
V
∂RSΔ
SG shunt
Replace Equation (B.26) with the following new equation:
2 U
o
G × SM × ×
t
∂S kU
Mi
× S (B.26)
V
∂RSΔ
SH shunt
Replace Equation (B.27) with the following new equation:
2 U
o
G × SM × ×
t
∂S kU
Mi
× S (B.27)
V
∂FSΔ
sens shunt
...