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Electromagnetic compatibility (EMC) -- Part 4-7: Testing and measurement techniques -
General guide on harmonics and interharmonics measurements and instrumentation, for
power supply systems and equipment connected thereto
Elektromagnetische Verträglichkeit (EMV) -- Teil 4-7: Prüf- und Messverfahren -
Allgemeiner Leitfaden für Verfahren und Geräte zur Messung von Oberschwingungen
und Zwischenharmonischen in Stromversorgungsnetzen und angeschlossenen Geräten
Compatibilité électromagnétique (CEM) -- Partie 4-7: Techniques d'essai et de mesure -
Guide général relatif aux mesures d'harmoniques et d'interharmoniques, ainsi qu'à
l'appareillage de mesure, applicable aux réseaux d'alimentation et aux appareils qui y
sont raccordés
Ta slovenski standard je istoveten z: EN 61000-4-7:2002/A1:2009
ICS:
33.100.20 Imunost Immunity
SIST EN 61000-4-7:2003/A1:2009 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN 61000-4-7:2003/A1:2009
---------------------- Page: 2 ----------------------
SIST EN 61000-4-7:2003/A1:2009
EUROPEAN STANDARD
EN 61000-4-7/A1
NORME EUROPÉENNE
March 2009
EUROPÄISCHE NORM
ICS 33.100.10; 33.100.20
English version
Electromagnetic compatibility (EMC) -
Part 4-7: Testing and measurement techniques -
General guide on harmonics and interharmonics measurements
and instrumentation,
for power supply systems and equipment connected thereto
(IEC 61000-4-7:2002/A1:2008)
Compatibilité électromagnétique (CEM) - Elektromagnetische Verträglichkeit (EMV) -
Partie 4-7: Techniques d'essai Teil 4-7: Prüf- und Messverfahren -
et de mesure - Allgemeiner Leitfaden für Verfahren
Guide général relatif aux mesures und Geräte zur Messung
d'harmoniques et d'interharmoniques, von Oberschwingungen
ainsi qu'à l'appareillage de mesure, und Zwischenharmonischen
applicable aux réseaux d'alimentation in Stromversorgungsnetzen
et aux appareils qui y sont raccordés und angeschlossenen Geräten
(CEI 61000-4-7:2002/A1:2008) (IEC 61000-4-7:2002/A1:2008)
This amendment A1 modifies the European Standard EN 61000-4-7:2002; it was approved by CENELEC on
2009-03-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this amendment the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This amendment exists in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CENELEC member into its own language and notified to the
Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: avenue Marnix 17, B - 1000 Brussels
© 2009 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61000-4-7:2002/A1:2009 E
---------------------- Page: 3 ----------------------
SIST EN 61000-4-7:2003/A1:2009
EN 61000-4-7:2002/A1:2009 - 2 -
Foreword
The text of document 77A/645/FDIS, future amendment 1 to IEC 61000-4-7:2002, prepared by SC 77A,
Low frequency phenomena, of IEC TC 77, Electromagnetic compatibility, was submitted to the
IEC-CENELEC parallel vote and was approved by CENELEC as amendment A1 to EN 61000-4-7:2002
on 2009-03-01.
The following dates were fixed:
– latest date by which the amendment has to be
implemented at national level by publication of
an identical national standard or by endorsement (dop) 2009-12-01
– latest date by which the national standards conflicting
with the amendment have to be withdrawn (dow) 2012-03-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of amendment 1:2008 to the International Standard IEC 61000-4-7:2002 was approved by
CENELEC as an amendment to the European Standard without any modification.
__________
---------------------- Page: 4 ----------------------
SIST EN 61000-4-7:2003/A1:2009
- 3 - EN 61000-4-7:2002/A1:2009
Replace Annex ZA of EN 61000-4-7:2002 by:
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year
1) 2) 3)
IEC 60038 - IEC standard voltages HD 472 S1 1989
+ corr. February 2002
A1 1995
1)
IEC 60050-161 - International Electrotechnical Vocabulary - -
(IEV) -
Chapter 161: Electromagnetic compatibility
1) 3)
IEC 61000-2-2 - Electromagnetic compatibility (EMC) - EN 61000-2-2 2002
Part 2-2: Environment - Compatibility levels
for low-frequency conducted disturbances and
signalling in public low-voltage power supply
systems
1) 3)
IEC 61000-3-2 - Electromagnetic compatibility (EMC) - EN 61000-3-2 2006
Part 3-2: Limits - Limits for harmonic current
emissions (equipment input current ≤ 16 A per
phase)
1) 3)
IEC 61000-3-12 - Electromagnetic compatibility (EMC) - EN 61000-3-12 2005
Part 3-12: Limits - Limits for harmonic currents
produced by equipment connected to public
low-voltage systems with input current > 16 A
and ≤ 75 A per phase
1)
Undated reference.
2)
The title of HD 472 S1 is: Nominal voltages for low-voltage public electricity supply systems.
3)
Valid edition at date of issue.
---------------------- Page: 5 ----------------------
SIST EN 61000-4-7:2003/A1:2009
---------------------- Page: 6 ----------------------
SIST EN 61000-4-7:2003/A1:2009
IEC 61000-4-7
Edition 2.0 2008-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Electromagnetic compatibility (EMC) –
Part 4-7: Testing and measurement techniques – General guide on harmonics
and interharmonics measurements and instrumentation, for power supply
systems and equipment connected thereto
Compatibilité électromagnétique (CEM) –
Partie 4-7: Techniques d'essai et de mesure – Guide général relatif aux mesures
d'harmoniques et d'interharmoniques, ainsi qu'à l'appareillage de mesure,
applicable aux réseaux d'alimentation et aux appareils qui y sont raccordés
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
T
CODE PRIX
ICS 33.100.10; 33.100.20 ISBN 2-8318-9848-X
---------------------- Page: 7 ----------------------
SIST EN 61000-4-7:2003/A1:2009
– 2 – 61000-4-7 Amend. 1 © IEC:2008
FOREWORD
This amendment has been prepared by subcommittee 77A: Low frequency phenomena, of
IEC technical committee 77: Electromagnetic compatibility.
The text of this amendment is based on the following documents:
FDIS Report on voting
77A/645/FDIS 77A/651/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
_____________
Page 13
2 Normative references
Insert, in the existing list, the following standards:
IEC 60038, IEC standard voltages
IEC 61000-2-2, Electromagnetic compatibility (EMC) – Part 2-2: Environment – Compatibility
levels for low-frequency conducted disturbances and signalling in public low-voltage power
supply systems
IEC 61000-3-12, Electromagnetic compatibility (EMC) – Part 3-12: Limits – Limits for
harmonic currents produced by equipment connected to public low-voltage systems with input
current >16 A and ≤75 A per phase
Delete from the existing list the following standard:
IEC 61967-1, Integrated circuits – Measurement of electromagnetic emissions, 150 kHz to
1 GHz – Part 1: Measurement conditions and definitions
Pages 15 and 17
3.1 Definitions related to frequency analysis
Replace the entire subclause, including the NOTES, by the following new text:
Notations: The following notations are used in the present guide for the Fourier series
development because it is easier to measure phase angles by observations of the zero
crossings:
---------------------- Page: 8 ----------------------
SIST EN 61000-4-7:2003/A1:2009
61000-4-7 Amend. 1 © IEC:2008 – 3 –
∞
k
⎛ ⎞
()
f t = c + c sin⎜ ω t + ϕ ⎟ (1)
0 ∑ k 1 k
N
⎝ ⎠
k =1
⎧
2 2
c = b + ja = a + b
k k k
⎪ k k
⎪
c
k
⎪
Y =
C,k
⎪
2
⎪
⎛ a ⎞ ⎛ a ⎞
⎪
k k
⎜ ⎟ ⎜ ⎟
ϕ =π + arctan if b < 0 ϕ = arctan if b > 0
k k k k
⎪ ⎟
⎜ ⎟ ⎜
b b
⎝ k ⎠ ⎝ k⎠
⎪
⎨
with: (2)
π π
⎪
ϕ = if b = 0 and a > 0 ϕ = − if b = 0 and a < 0
k k k k k k
2 2
⎪
⎪
ϕ = 0 if b ≤ ε and a ≤ ε,
k k k
⎪
⎪
with ε = 0,05 % U and ε = 0,15 % I
nom nom
⎪
or ε = 0,15 % U and ε = 0,5 % I
⎪ nom nom
⎪
respectively, see table 1 in IEC 61000-4-7
⎩
T
⎧
N
2 ⎛ k ⎞
⎪
b = f()t × sin ω t dt
⎜ ⎟
k 1
∫
⎪
T N
⎝ ⎠
N
⎪ 0
⎪
T
N
⎪
2 k
⎛ ⎞
a = f()t × cos ω t dt
⎜ ⎟
⎨
and: k 1 (3)
∫
T N
⎝ ⎠
N
⎪
0
⎪
T
N
⎪
1
⎪
c = f()t dt
0
∫
⎪ T
N
0
⎩
NOTE 1 The above definition setting φ to zero for the cases where b and a have very small values provides
k k k
guidance to instrument manufacturers, as phase measurements of very small amplitudes may result in very large
deviations, hence there is no requirement to measure phase for such small signals.
ω is the angular frequency of the fundamental (ω = 2πf );
1 1 H,1
T is the width (or duration) of the time window; the time window is that time span of a time
N
function over which the Fourier transform is performed;
c is the d.c. component;
0
k
c is the amplitude of the component with frequency f = f ;
k C,k H,1
N
Y is the r.m.s. value of component c ;
C,k k
f is the fundamental frequency of the power system;
H,1
k is the ordinal number (order of the spectral component) related to the frequency resolution
⎛ ⎞
1
f = ;
⎜ ⎟
C,1
T
N
⎝ ⎠
N is the number of fundamental periods within the window width;
ϕ is the phase angle of spectral line k.
k
---------------------- Page: 9 ----------------------
SIST EN 61000-4-7:2003/A1:2009
– 4 – 61000-4-7 Amend. 1 © IEC:2008
NOTE 2 Strictly speaking these definitions apply to steady-state signals only. The Fourier series is actually in
most cases performed digitally, i.e. as a Discrete Fourier Transform DFT, or a variant thereof, being the FFT.
The analogue signal f(t) which has to be analyzed is sampled, A/D-converted and stored. Each group of M samples
forms a time window on which DFT is performed. According to the principles of Fourier series expansion, the
window width T determines the frequency resolution f = 1/T (i.e. the frequency separation of the spectral
N C,1 N
components) for the analysis. Therefore the window width T must be an integer multiple N of the fundamental
N
period T of the system voltage: T = N × T . The sampling rate is in this case f = M/(NT ) (where M = number of
1
1 s
1 N
samples within T ).
N
Before DFT-processing, the samples in the time window are often weighted by multiplying them with a special
symmetrical function ('windowing function'). However, for periodic signals and synchronous sampling it is
preferable to use a rectangular weighting window which multiplies each sample by unity.
The DFT-processor yields the orthogonal Fourier-coefficients a and b of the corresponding spectral-component
k k
frequencies f = k/T , k = 0, 1, 2 . M-1. However, only k values up to and including half of the maximum value are
C,k N
useful, the other half just duplicates them.
Under synchronized conditions, the component of harmonic order h related to the fundamental frequency f
H,1
appears as the spectral component of order k, where k = hN.
NOTE 3 The Fast Fourier Transform FFT is a special algorithm allowing short computation times. It requires that
i
the number of samples M be an integer power of 2, M = 2 , with i ≥ 10 for example.
NOTE 4 The symbol Y is replaced, as required by the symbol I for currents, by the symbol U for voltages. Index C
qualifies the variable as spectral component.
Page 17
3.2 Definitions related to harmonics
Replace the existing terms and definitions 3.2.1 to 3.2.5, including NOTES, if any, by the
following:
3.2.1
harmonic frequency
f
H,h
frequency which is an integer multiple of the fundamental frequency of the power system
(f = h × f )
H,h H,1
NOTE The harmonic frequency f is identical with the component frequency f with k = h × N.
H,h C,k
3.2.2
harmonic order
h
(integer) ratio of a harmonic frequency to the fundamental frequency of the power system. In
connection with the analysis using DFT and synchronisation between f and f (sampling
H,1 s
rate), the harmonic order h corresponds to the spectral component k = h × N (k = number of
the spectral component, N = number of periods of the fundamental frequency in time window
T )
N
3.2.3
r.m.s. value of a harmonic component
Y
H,h
r.m.s. value of one of the components having a harmonic frequency in the analysis of a non-
sinusoidal waveform
For brevity, such a component may be referred to simply as a “harmonic”
NOTE 1 The harmonic component Y is identical with the spectral component Y with k = h×N;
H,h C,k
(Y = Y ). The symbol Y is replaced, as required by the symbol I for currents, by the symbol U for voltages.
H,h C,h×N
The index H qualifies the variable I or U as harmonic.
NOTE 2 For the purposes of this standard, the time window has a width of N = 10 (50 Hz systems) or N = 12
(60 Hz system) fundamental periods, i.e. approximately 200 ms (see 4.4.1). This yields Y = Y (50 Hz
H,h C,10×h
systems) and Y = Y (60 Hz systems).
H,h C,12×h
---------------------- Page: 10 ----------------------
SIST EN 61000-4-7:2003/A1:2009
61000-4-7 Amend. 1 © IEC:2008 – 5 –
Page 19
3.2.4
r.m.s. value of a harmonic group
Y
g,h
square root of the sum of the squares of the r.m.s. value of a harmonic and the spectral
components adjacent to it within the time window, thus summing the energy contents of the
neighbouring components with that of the harmonic proper. See also equation 8 and Figure 4.
The harmonic order is given by the harmonic considered.
NOTE The symbol Y is replaced, as required by the symbol I for currents, by the symbol U for voltages.
3.2.5
r.m.s. value of a harmonic subgroup
Y
sg,h
square root of the sum of the squares of the r.m.s. value of a harmonic and the two spectral
components immediately adjacent to it. For the purpose of including the effect of voltage
fluctuation during voltage surveys, a subgroup of output components of the DFT is obtained
by summing the energy contents of the frequency components directly adjacent to a harmonic
with that of the harmonic proper. (See also equation 9 and Figure 6.) The harmonic order is
given by the harmonic considered
NOTE The symbol Y is replaced, as required by the symbol I for currents, by the symbol U for voltages.
Page 19
3.3 Definitions related to distortion factors
Replace the existing terms and definitions 3.3.1 to 3.3.4, including NOTES, if any, by the
following:
3.3.1
total harmonic distortion
THD
THD (symbol)
Y
ratio of the r.m.s. value of the sum of all the harmonic components ( Y ) up to a specified
H,h
order (h ) to the r.m.s. value of the fundamental component (Y ):
max H,1
2
h
max
⎛ ⎞
Y
H,h
⎜ ⎟
THD = (4)
Y ∑
⎜ ⎟
Y
⎝ ⎠
H,1
h=2
NOTE 1 The symbol Y is replaced, as required, by the symbol I for currents or by the symbol U for voltages.
NOTE 2 The value of h is 40 if no other value is defined in a standard concerned with limits (IEC 61000-3
max
series).
3.3.2
group total harmonic distortion
THDG
THDG (symbol)
Y
ratio of the r.m.s. value of the harmonic groups (Y ) to the r.m.s. value of the group
g,h
associated with the fundamental (Y ):
g,1
2
h
max
⎛ ⎞
Y
g,h
⎜ ⎟
THDG = where h ≥ 2 (5)
Y ∑ min
⎟
⎜
Y
⎝ g,1⎠
h=h
min
NOTE 1 The symbol Y is replaced, as required, by the symbol I for currents or by the symbol U for voltages.
NOTE 2 The value of h is 2 and that of h is 40 if no other values are defined in a standard concerned with limits (for example
min max
IEC 61000-3 series).
---------------------- Page: 11 ----------------------
SIST EN 61000-4-7:2003/A1:2009
– 6 – 61000-4-7 Amend. 1 © IEC:2008
Page 21
3.3.3
THDS
subgroup total harmonic distortion
THDS (symbol)
Y
ratio of the r.m.s. value of the harmonic sub-groups (Y ) to the r.m.s. value of the sub-group
sg,h
associated with the fundamental (Y ):
sg,1
2
h
max
⎛ ⎞
Y
sg,h
⎜ ⎟
THDS = where h ≥ 2 (6)
Y ∑
min
⎜ ⎟
Y
⎝ sg,1⎠
h=h
min
NOTE 1 The symbol Y is replaced, as required, by the symbol I for currents or by the symbol U for voltages.
NOTE 2 The value of h is 2 and that of h is 40 if no other values are defined in a standard concerned with
min max
limits (for example IEC 61000-3 series).
3.3.4
partial weighted harmonic distortion
PWHD
PWHD (symbol)
H,Y
ratio of the r.m.s. value, weighted with the harmonic order h, of a selected group of higher
order harmonics (from the order h to h ) to the r.m.s. value of the fundamental:
min max
2
h
max
⎛ ⎞
Y
H,h
⎜ ⎟
PWHD = h (7)
Y
H, ∑
⎜ ⎟
Y
H,1
⎝ ⎠
h=h
min
NOTE 1 The symbol Y is replaced, as required, by the symbol I for currents or by the symbol U for voltages.
NOTE 2 The concept of partial weighted harmonic distortion is introduced to allow for the possibility of specifying
a single limit for the aggregation of higher order harmonic components. The partial weighted group harmonic
distortion PWHD can be evaluated by replacing the quantity Y by the quantity Y . The partial weighted sub-
g Y H,h g,h
,
group harmonic distortion PWHD can be evaluated by replacing the quantity Y by the quantity Y . The type of
sg,Y H,h sg,h
PWHD (PWHD , PWHD or PWHD ) is defined in each standard which uses the PWHD, for example in standards concerned
H,Y g,Y sg,Y
with limits (IEC 61000-3 series).
NOTE 3 The values of h and h are defined in each standard which uses the PWHD , for example in a standard
min max
Y
concerned with limits (IEC 61000-3 series).
Page 21
3.4 Definitions related to interharmonics
Replace the existing terms and definitions 3.4.1 to 3.4.5, including NOTES, if any, by the
following:
3.4.1
r.m.s. value of a spectral component
Y
C,k
in the analysis of a waveform, the r.m.s. value of a component whose frequency is a multiple
of the inverse of the duration of the time window
NOTE 1 If the duration of the time window is multiple of the fundamental period, only some of the spectral
components have frequencies which are integer multiples of the fundamental frequency.
NOTE 2 The frequency interval between two consecutive spectral components is the inverse of the width of the
time window, approximately 5 Hz for the purposes of this standard.
NOTE 3 The symbol Y is replaced, as required, by the symbol I for currents or by the symbol U for voltages.
---------------------- Page: 12 ----------------------
SIST EN 61000-4-7:2003/A1:2009
61000-4-7 Amend. 1 © IEC:2008 – 7 –
3.4.2
r.m.s. value of an interharmonic component
Y
C,i
r.m.s. value of a spectral component, Y , with a frequency between two consecutive
C,k ≠ h × N
harmonic frequencies (see Figure 4). For brevity, such a component may be referred to simply
as an “interharmonic”.
NOTE 1 The frequency of the interharmonic component is given by the frequency of the spectral line. This
frequency is not an integer multiple of the fundamental frequency.
NOTE 2 A difference is made between an “interharmonic component” produced as a physical component by an
equipment, for example at 183,333 Hz, and a “spectral component” calculated by the instrument as the result of the
waveform analysis e.g. for a 50 Hz system at 185 Hz (the frequency of the FFT bin). The “spectral component” is
also the “harmonic component” for h × N where h is an integer.
Page 23
3.4.3
r.m.s. value of an interharmonic group
Y
ig,h
r.m.s. value of all spectral components in the interval between two consecutive harmonic
frequencies (see Figure 4).
NOTE 1 For the purpose of this standard, the r.m.s. value of the interharmonic group between the harmonic
orders h and h + 1 is designated as Y , for example the group between h = 5 and h = 6 is designated as Y .
ig,h ig,5
NOTE 2 The symbol Y is replaced, as required, by the symbol I for currents or by the symbol U for voltages.
3.4.4
r.m.s. value of an interharmonic centred subgroup
Y
isg,h
r.m.s. value of all spectral components in the interval between two consecutive harmonic
frequencies, excluding spectral components directly adjacent to the harmonic frequencies
(see Figure 6)
NOTE 1 For the purpose of this standard, the r.m.s. value of the centred subgroup between the harmonic orders h
and h + 1 is designated as Y , for example the centred subgroup between h = 5 and h = 6 is designated as Y .
isg,h isg,5
NOTE 2 The symbol Y is replaced, as required, by the symbol I for currents or by the symbol U for voltages.
3.4.5
interharmonic group frequency
f
ig,h
mean of the two harmonic frequencies between which the group is situated, i.e. f = (f +
ig,h H,h
f )/2.
H,h+1
Add the following new term and definition:
3.4.6
interharmonic centred subgroup frequency
f
isg,h
mean of the two harmonic frequencies between which the subgroup is situated, i.e. f =
isg,h
(f + f )/2.
H,h H,h+1
Pages 23 and 25
3.5 Notations
Replace the entire subclause by the following new subclause:
3.5.1 Symbols
In this standard, voltage and current values are r.m.s. unless otherwise stated.
a amplitude coefficient of a cosine component in a Fourier series
b amplitude coefficient of a sine component in a Fourier series
---------------------- Page: 13 ----------------------
SIST EN 61000-4-7:2003/A1:2009
– 8 – 61000-4-7 Amend. 1 © IEC:2008
c amplitude coefficient in a Fourier series
f frequency; function
f
C,k spectral component frequency of order k
f the frequency of the spectral component of order 1. The frequency resolution is equal to this
C,1
frequency
f
g,h harmonic-group frequency of order h
f
sg,h harmonic-subgroup frequency of order h
f
ig,h interharmonic-group frequency of order h
f
isg,h interharmonic centred subgroup frequency of order h
f
H,h harmonic component frequency of order h
f
H,1 fundamental frequency of the power system
f sampling rate
s
h the order of the highest harmonic that is taken into account
max
h the order of the lowest harmonic that is taken into account
min
j −1
t running time
B bandwidth
I current (r.m.s. value)
M integer number; number of samples within the window width
N number of power supply periods within the window width
P power
T time interval
T fundamental period of the power supply system
1
T window width comprising N fundamental periods
N
U voltage (r.m.s. value)
Y Variable replaceable by I, U
Y r.m.s. value of the spectral component of order k
C,k
Y r.m.s. value of harmonic group
g,h
Y r.m.s. value of the harmonic component of order h
H,h
Y r.m.s. value of interharmonic group
ig,h
Y r.m.s. value of interharmonic centred subgroup
isg,h
Y r.m.s. value of harmonic subgroup
sg,h
ω angular frequency
ω angular frequency of the power supply
1
ϕ phase angle
Page 25
Replace the entire subclause by the following new subclause:
3.5.2 Subscripts
b centre-band frequency
h running-integer number for harmonic orders
k running-integer number for spectral components
m measured value
---------------------- Page: 14 ----------------------
SIST EN 61000-4-7:2003/A1:2009
61000-4-7 Amend. 1 © IEC:2008 – 9 –
max maximum value
min minimum value
o smoothed value
g grouped value
sg sub-grouped value
i interharmonic value
g,h harmonic group associated with harmonic order h
sg,h harmonic subgroup associated with harmonic order h
ig,h interharmonic group above harmonic order h
isg,h interharmonic centred sub-group above harmonic order h
og,h smoothed harmonic group of order h
nom nominal value
s sampled
C value related to spectral component
H harmonic
f frequency
0 d.c. related
Page 25
4.1 Characteristics of the signal to be measured
Replace the existing text of this subclause by the following new text:
Instruments for the following types of measurement are considered:
a) harmonic emission measurement,
b) interharmonic emission measurement,
c) measurements above harmonic frequency range up to 9 kHz.
Strictly speaking the (Fast) Fourier Transform produces accurate results for steady state
signals only. Signals whose amplitudes vary with time cannot be described correctly by their
harmonic components only. In order to obtain reproducible harmonic emission analysis results
when measuring products with fluctuating power, and thus fluctuating fundamental current
and possibly fluctuating harmonic current levels, a combination of averaging techniques and
sufficiently long measurement cycles can be used. This standard therefore provides a
simplified method employing specific averaging methods (see 5.5.1). Furthermore, a test
observation period, long enough to obtain successive measurement results that are within
acceptable tolerance levels is specified in the harmonic emission standards referring to this
standard.
Page 27
4.4.1 Main instrument
Replace, in the fourth dashed item of the first paragraph:
"a " by "a " and "b " by "b "
m k m k
Replace, the entire third paragraph (paragraph below Note 2) by the following new text:
The window width shall be 10 (50 Hz systems) or 12 (60 Hz systems) fundamental periods (T
N
= [10 or 12] × T ≈ 200ms) with rectangular weighting, synchronized to the fundamental
1
frequency of the power system. Hanning weighting is allowed only in the case of loss of
synchronisation. The loss of synchronization shall be indicated on the instrument display and
---------------------- Page: 15 ----------------------
SIST EN 61000-4-7:2003/A1:2009
– 10 – 61000-4-7 Amend. 1 © IEC:2008
the data so acquired shall be flagged and shall not be used for the purpose of determining
compliance, but may be used for other purposes.
Replace the fifth paragraph (last paragraph before Figure 1) by the following new text:
The output OUT 1 (see Figure 1) shall provide the individual coefficients a and b of the DFT
k k
as well as Y , for the current or voltage, i.e. the value of each frequency component
C,k
calculated.
Page 29
Figure 1 – General structure of the measuring instrument
Replace the existing figure by the following new figure:
Sampling
frequency
generation
Input
Preprocessing
voltage
Sampling &
Main instrument
DFT OUT 1 (a , b , Y )
k k C,k
Conversion
Input
Preprocessing
current
Grouping
Input for Active Power
see notes 3 and 4
OUT 2a (Y )
g,h
Smoothing
OUT 2b (Y )
og,h
Check for
Compliance
OUT 3 (pass or fail)
IEC 858/08
Page 33
5.3 Accuracy requirements
Table 1 – Accuracy requirements for current, voltage and power measurements
Replace, in the last column, in the third row of Class I:
"P " by "P ".
nom m
Replace in the existing third explanatory note by the following:
U and I : Measured values by U , I and P : Measured values.
m m m m m
---------------------- Page: 16 ----------------------
SIST EN 61000-4-7:2003/A1:2009
61000-4-7 Amend. 1 © IEC:2008 – 11 –
Replace the existing NOTE 2 by the following new NOTE:
NOTE 2 Class I instruments are recommended for emission measurements, Class II is recommended for general
surveys, but can also be used for emission measurements if the values are such that, even allowing for the
increased uncertainty, it is clear that the limits are not exceeded. In practice, this means that the measured values
of harmonics should be <90 % of the allowed limits.
Replace the existing NOTE 3 by the following new NOTE:
NOTE 3 Additionally, for Class I instruments, the phase shift between individual channels should be smaller than
h × 1º.
Pages 35 and 37
5.4 Measurement set-up for emission assessment
Replace the title and the entire text and figures of this subclause by the following new titles,
figures and text:
5.4 Measurement set-up and supply voltage
5.4.1 Measurement set-up for emission assessment
The measurement set-up is given in Figures 2 and 3.
Key
Δ
U L
U Source voltage l
...