IEC 61000-4-30:2008
(Main)Electromagnetic compatibility (EMC) - Part 4-30: Testing and measurement techniques - Power quality measurement methods
Electromagnetic compatibility (EMC) - Part 4-30: Testing and measurement techniques - Power quality measurement methods
IEC 61000-4-30:2008 defines the methods for measurement and interpretation of results for power quality parameters in 50/60 Hz a.c. power supply systems. Measurement methods are described for each relevant parameter in terms that give reliable and repeatable results, regardless of the method's implementation. This standard addresses measurement methods for in situ measurements. Measurement of parameters covered by this standard is limited to voltage phenomena that can be conducted in a power system. The power quality parameters considered in this standard are power frequency, magnitude of the supply voltage, flicker, supply voltage dips and swells, voltage interruptions, transient voltages, supply voltage unbalance, voltage harmonics and interharmonics, mains signalling on the supply voltage and rapid voltage changes. Depending on the purpose of the measurement, all or a subset of the phenomena on this list may be measured. IEC 61000-4-30:2008 gives measurement methods and appropriate performance requirements, but does not set thresholds. The effects of transducers inserted between the power system and the instrument are acknowledged but not addressed in detail in this standard. Precautions on installing monitors on live circuits are addressed. IEC 61000-4-30:2008 has the status of a basic EMC publication in accordance with IEC Guide 107. This second edition cancels and replaces the first edition published in 2003. This edition includes the following significant technical changes with respect to the previous edition:
- Adjustments, clarifications, and corrections to class A and class B measurement methods.
- A new category, class S, intended for survey instruments, has been added.
- A new Annex C gives guidance on instruments.
Compatibilité électromagnétique (CEM) - Partie 4-30: Techniques d'essai et de mesure - Méthodes de mesure de la qualité de l'alimentation
La CEI 61000-4-30:2008 définit les méthodes de mesure des paramètres de qualité de l'alimentation des réseaux à courant alternatif 50/60 Hz et la façon d'interpréter les résultats. Les méthodes de mesure sont décrites pour chaque paramètre applicable en des termes qui fournissent des résultats fiables et répétitifs indépendamment de l'implémentation de la méthode. La présente norme porte sur les méthodes de mesure destinées aux mesures in situ. La mesure des paramètres couverts par la présente norme se limite aux phénomènes en tension susceptibles de se propager sur un réseau d'énergie électrique. Les paramètres de qualité de l'alimentation pris en compte dans la présente norme sont la fréquence, l'amplitude de la tension d'alimentation, le papillotement ("flicker"), les creux et les surtensions temporaires d'alimentation, les coupures de tension, les tensions transitoires, le déséquilibre de tension d'alimentation, les harmoniques et interharmoniques de tension, les signaux transmis sur la tension d'alimentation et les variations rapides de tension. En fonction de l'objet de la mesure, les mesures peuvent porter soit sur une partie des phénomènes de cette liste, soit sur l'ensemble. La CEI 61000-4-30:2008 fournit des méthodes de mesure et des exigences de performances appropriées sans fixer de seuils. Les effets des transducteurs lorsqu'ils sont placés entre le réseau et l'appareil de mesure sont pris en compte mais non traités en détail dans la présente norme. Les précautions à prendre pour installer des appareils de mesure sur des circuits sous tension sont indiquées dans la présente norme. La CEI 61000-4-30:2008 a le statut de publication fondamentale en CEM conformément au guide 107 de la CEI. Cette deuxième édition annule et remplace la première édition parue en 2003. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- Ajustements, clarifications et corrections sur les méthodes de mesures pour la classe A et la classe B.
- Une nouvelle catégorie, la classe S, destinée aux appareils de mesure pour des campagnes statistiques, a été ajoutée.
- Une nouvelle annexe C fournit des recommandations sur les appareils de mesure.
General Information
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Standards Content (Sample)
IEC 61000-4-30
Edition 2.0 2008-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC EMC PUBLICATION
PUBLICATION FONDAMENTALE EN CEM
Electromagnetic compatibility (EMC) –
Part 4-30: Testing and measurement techniques – Power quality measurement
methods
Compatibilité électromagnétique (CEM) –
Partie 4-30: Techniques d’essai et de mesure – Méthodes de mesure de la qualité
de l’alimentation
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IEC 61000-4-30
Edition 2.0 2008-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC EMC PUBLICATION
PUBLICATION FONDAMENTALE EN CEM
Electromagnetic compatibility (EMC) –
Part 4-30: Testing and measurement techniques – Power quality measurement
methods
Compatibilité électromagnétique (CEM) –
Partie 4-30: Techniques d’essai et de mesure – Méthodes de mesure de la
qualité de l’alimentation
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XB
CODE PRIX
ICS 33.100.99 ISBN 978-2-88910-391-1
– 2 – 61000-4-30 © IEC:2008
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references.7
3 Terms and definitions .8
4 General .12
4.1 Classes of measurement methods .12
4.2 Organization of the measurements.13
4.3 Electrical values to be measured.13
4.4 Measurement aggregation over time intervals .14
4.5 Measurement aggregation algorithm .14
4.5.1 Requirements .14
4.5.2 150/180 cycle aggregation .14
4.5.3 10 min aggregation .15
4.5.4 2 hour aggregation.18
4.6 Real time clock (RTC) uncertainty.18
4.7 Flagging concept .18
5 Power quality parameters.19
5.1 Power frequency.19
5.1.1 Measurement method .19
5.1.2 Measurement uncertainty and measuring range.19
5.1.3 Measurement evaluation .19
5.1.4 Aggregation .19
5.2 Magnitude of the supply voltage.20
5.2.1 Measurement method .20
5.2.2 Measurement uncertainty and measuring range.20
5.2.3 Measurement evaluation .20
5.2.4 Aggregation .20
5.3 Flicker .20
5.3.1 Measurement method .20
5.3.2 Measurement uncertainty and measuring range.20
5.3.3 Measurement evaluation .21
5.3.4 Aggregation .21
5.4 Supply voltage dips and swells.21
5.4.1 Measurement method .21
5.4.2 Detection and evaluation of a voltage dip .22
5.4.3 Detection and evaluation of a voltage swell .22
5.4.4 Calculation of a sliding reference voltage .23
5.4.5 Measurement uncertainty and measuring range.23
5.4.6 Aggregation .24
5.5 Voltage interruptions.24
5.5.1 Measurement method .24
5.5.2 Evaluation of a voltage interruption .24
5.5.3 Measurement uncertainty and measuring range.25
5.5.4 Aggregation .25
5.6 Transient voltages .25
61000-4-30 © IEC:2008 – 3 –
5.7 Supply voltage unbalance .25
5.7.1 Measurement method .25
5.7.2 Measurement uncertainty and measuring range.26
5.7.3 Measurement evaluation .26
5.7.4 Aggregation .26
5.8 Voltage harmonics .26
5.8.1 Measurement method .26
5.8.2 Measurement uncertainty and measuring range.27
5.8.3 Measurement evaluation .27
5.8.4 Aggregation .27
5.9 Voltage interharmonics .27
5.9.1 Measurement method .27
5.9.2 Measurement uncertainty and measuring range.28
5.9.3 Measurement evaluation .28
5.9.4 Aggregation .28
5.10 Mains signalling voltage on the supply voltage .28
5.10.1 Measurement method .28
5.10.2 Measurement uncertainty and measuring range.29
5.10.3 Measurement evaluation .29
5.10.4 Aggregation .29
5.11 Rapid Voltage Changes (RVC).29
5.12 Measurement of underdeviation and overdeviation parameters.29
5.12.1 Measurement method .29
5.12.2 Measurement uncertainty and measuring range.30
5.12.3 Aggregation .30
6 Range of influence quantities and steady-state verification .30
6.1 Range of influence quantities.30
6.2 Steady-state performance verification .32
Annex A (informative) Power quality measurements – Issues and guidelines.34
Annex B (informative) Power quality measurement – Guidance for applications .47
Annex C (informative) Guidance on instruments .59
Bibliography .62
Figure 1 – Measurement chain .13
Figure 2 – Synchronization of aggregation intervals for Class A .15
Figure 3 – Synchronization of aggregation intervals for class S: parameters for which
gaps are not permitted .16
Figure 4 – Synchronization of aggregation intervals for class S: parameters for which
gaps are permitted (see 4.5.2).17
Figure 5 – Example of supply voltage unbalance uncertainty.26
Figure A.1 – Frequency spectrum of typical representative transient test waveforms .40
Table 1 – Influence quantity range.31
Table 2 – Uncertainty steady-state verification for class A and class S.33
Table C.1 – Summary of requirements.60
– 4 – 61000-4-30 © IEC:2008
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4-30: Testing and measurement techniques –
Power quality measurement methods
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
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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
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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
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
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6) All users should ensure that they have the latest edition of this publication.
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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 IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61000-4-30 has been prepared by subcommittee 77A: Low-
frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
This standard forms part 4-30 of IEC 61000. It has the status of a basic EMC publication in
accordance with IEC Guide 107.
This second edition cancels and replaces the first edition published in 2003. This edition
includes the following significant technical changes with respect to the previous edition.
– Adjustments, clarifications, and corrections to class A and class B measurement methods.
– A new category, class S, intended for survey instruments, has been added.
– A new Annex C gives guidance on instruments.
61000-4-30 © IEC:2008 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
77A/660/FDIS 77A/666/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61000 series, under the general title Electromagnetic compatibility
(EMC), can be found on the IEC website.
The committee has decided that the contents of this 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.
– 6 – 61000-4-30 © IEC:2008
INTRODUCTION
IEC 61000 is published in separate parts according to the following structure:
Part 1: General
General considerations (introduction, fundamental principles)
Definitions, terminology
Part 2: Environment
Description of the environment
Classification of the environment
Compatibility levels
Part 3: Limits
Emission limits
Immunity limits (in so far as they do not fall under the responsibility of the product
committees)
Part 4: Testing and measurement techniques
Measurement techniques
Testing techniques
Part 5: Installation and mitigation guidelines
Installation guidelines
Mitigation methods and devices
Part 6: Generic standards
Part 9: Miscellaneous
Each part is further subdivided into several parts, published either as International Standards
or as Technical Specifications or Technical Reports, some of which have already been
published as sections. Others will be published with the part number followed by a dash and
completed by a second number identifying the subdivision (example: IEC 61000-6-1).
61000-4-30 © IEC:2008 – 7 –
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4-30: Testing and measurement techniques –
Power quality measurement methods
1 Scope
This part of IEC 61000-4 defines the methods for measurement and interpretation of results for
power quality parameters in 50/60 Hz a.c. power supply systems.
Measurement methods are described for each relevant parameter in terms that give reliable
and repeatable results, regardless of the method’s implementation. This standard addresses
measurement methods for in situ measurements.
Measurement of parameters covered by this standard is limited to voltage phenomena that can
be conducted in a power system. The power quality parameters considered in this standard are
power frequency, magnitude of the supply voltage, flicker, supply voltage dips and swells,
voltage interruptions, transient voltages, supply voltage unbalance, voltage harmonics and
interharmonics, mains signalling on the supply voltage and rapid voltage changes. Depending
on the purpose of the measurement, all or a subset of the phenomena on this list may be
measured.
NOTE 1 Information about current parameters may be found in A.3 and A.5.
This standard gives measurement methods and appropriate performance requirements, but
does not set thresholds.
The effects of transducers inserted between the power system and the instrument are
acknowledged but not addressed in detail in this standard. Precautions on installing monitors
on live circuits are addressed.
NOTE 2 Some guidance about effects of transducers may be found in IEC 61557-12.
2 Normative references
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.
IEC 60050-161, International Electrotechnical Vocabulary (IEV) – Chapter 161: Electro-
magnetic compatibility
IEC 61000-2-2:2002, Electromagnetic compatibility (EMC) – Part 2-2: Environment –
Compatibility levels for low-frequency conducted disturbances and signalling in public low-
voltage power supply systems
IEC 61000-2-4, Electromagnetic compatibility (EMC) – Part 2-4: Environment – Compatibility
levels in industrial plants for low-frequency conducted disturbances
IEC 61000-3-8, Electromagnetic compatibility (EMC) – Part 3: Limits – Section 8: Signalling on
low-voltage electrical installations – Emission levels, frequency bands and electromagnetic
disturbance levels
– 8 – 61000-4-30 © IEC:2008
IEC 61000-4-4:2004, Electromagnetic compatibility (EMC) – Part 4-4: Testing and measure-
ment techniques – Electrical fast transient/burst immunity test
IEC 61000-4-7:2002, Electromagnetic compatibility (EMC) – Part 4-7: Testing and measure-
ment techniques – General guide on harmonics and interharmonics measurements and
instrumentation, for power supply systems and equipment connected thereto
Amendment 1 (2008)
IEC 61000-4-15, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 15: Flickermeter – Functional and design specifications
IEC 61180 (all parts), High-voltage test techniques for low voltage equipment
3 Terms and definitions
For the purpose of this document, the definitions of IEC 60050-161, as well as the following,
apply.
3.1
channel
individual measurement path through an instrument
NOTE “Channel” and “phase” are not the same. A voltage channel is by definition the difference in potential
between 2 conductors. Phase refers to a single conductor. On polyphase systems, a channel may be between 2
phases, or between a phase and neutral, or between a phase and earth, or between neutral and earth.
3.2
Coordinated Universal Time
UTC
time scale which forms the basis of a coordinated radio dissemination of standard frequencies
and time signals. It corresponds exactly in rate with international atomic time, but differs from it
by an integral number of seconds.
NOTE 1 Coordinated universal time is established by the International Bureau of Weights and Measures (BIPM)
and the International Earth Rotation Service (IERS).
NOTE 2 The UTC scale is adjusted by the insertion or deletion of seconds, so called positive or negative leap
seconds, to ensure approximate agreement with UT1.
[IEV 713-05-20]
3.3
declared input voltage
U
din
value obtained from the declared supply voltage by a transducer ratio
3.4
declared supply voltage
U
c
declared supply voltage U is normally the nominal voltage U of the system. If, by agreement
c n
between the supplier and the customer, a voltage different from the nominal voltage is applied
to the terminal, then this voltage is the declared supply voltage U
c
3.5
dip threshold
voltage magnitude specified for the purpose of detecting the start and the end of a voltage dip
61000-4-30 © IEC:2008 – 9 –
3.6
flagged data
data that has been marked to indicate that its measurement or its aggregation may have been
affected by interruptions, dips, or swells
NOTE Flagging enables other methods that may prevent a single event from being counted as several different
types of events. Flagging is supplemental information about a measurement or aggregation. Flagged data is not
removed from the data set. In some applications, flagged data may be excluded from further analysis but in other
applications, the fact that data was flagged may be unimportant. The user, application, regulation, or other
standards determine the use of flagged data. See 4.7 for further explanation.
3.7
flicker
impression of unsteadiness of visual sensation induced by a light stimulus whose luminance or
spectral distribution fluctuates with time
[IEV 161-08-13]
3.8
fundamental component
component whose frequency is the fundamental frequency
[IEV 101-14-49, modified]
3.9
fundamental frequency
frequency in the spectrum obtained from a Fourier transform of a time function, to which all the
frequencies of the spectrum are referred
[IEV 101-14-50, modified]
NOTE In case of any remaining risk of ambiguity, the fundamental frequency may be derived from the number of
poles and speed of rotation of the synchronous generator(s) feeding the system.
3.10
harmonic component
any of the components having a harmonic frequency
[IEC 61000-2-2:2002, 3.2.4, modified]
NOTE Its value is normally expressed as an r.m.s. value. For brevity, such component may be referred to simply
as a harmonic.
3.11
harmonic frequency
frequency which is an integer multiple of the fundamental frequency
NOTE The ratio of the harmonic frequency to the fundamental frequency is the harmonic order (notation: h).
3.12
hysteresis
difference in magnitude between the start and end thresholds
NOTE 1 This definition of hysteresis is relevant to Power Quality (PQ) measurement parameters and is different
from the IEV definition which is relevant to iron core saturation.
NOTE 2 The purpose of hysteresis in the context of PQ measurements is to avoid counting multiple events when
the magnitude of the parameter oscillates about the threshold level.
3.13
influence quantity
any quantity which may affect the working performance of a measuring equipment
– 10 – 61000-4-30 © IEC:2008
[IEV 311-06-01, modified]
NOTE This quantity is generally external to the measurement equipment.
3.14
interharmonic component
component having an interharmonic frequency
[IEC 61000-2-2:2002, 3.2.6]
NOTE Its value is normally expressed as an r.m.s. value. For brevity, such a component may be referred to simply
as an interharmonic.
3.15
interharmonic frequency
any frequency which is not an integer multiple of the fundamental frequency
[IEC 61000-2-2:2002, 3.2.5]
3.16
interruption
reduction of the voltage at a point in the electrical system below the interruption threshold
3.17
interruption threshold
voltage magnitude specified for the purpose of detecting the start and the end of a voltage
interruption
3.18
measurement uncertainty
parameter, associated with the result of a measurement, that characterizes the dispersion of
the values that could reasonably be attributed to the measurand
[IEV 311-01-02]
3.19
nominal voltage
U
n
voltage by which a system is designated or identified
3.20
overdeviation
absolute value of the difference between the measured value and the nominal value of a
parameter, only when the measured value of the parameter is greater than the nominal value
3.21
power quality
characteristics of the electricity at a given point on an electrical system, evaluated against a set
of reference technical parameters
NOTE These parameters might, in some cases, relate to the compatibility between electricity supplied on a
network and the loads connected to that network.
61000-4-30 © IEC:2008 – 11 –
3.22
Real-Time Clock
RTC
local timekeeping device used for implementing certain methods in this standard.
NOTE The relationship between the real-time clock and UTC is defined in 4.6.
3.23
r.m.s. (root-mean-square) value
square root of the arithmetic mean of the squares of the instantaneous values of a quantity
taken over a specified time interval and a specified bandwidth
[IEV 101-14-16, modified]
3.24
r.m.s. voltage refreshed each half-cycle
U
rms(1/2)
value of the r.m.s. voltage measured over 1 cycle, commencing at a fundamental zero crossing,
and refreshed each half-cycle
NOTE 1 This technique is independent for each channel and will produce r.m.s. values at successive times on
different channels for polyphase systems.
NOTE 2 This value is used only for voltage dip, voltage swell and interruption detection and evaluation, in Class A.
NOTE 3 This r.m.s. voltage value may be a phase-to-phase value or a phase-to-neutral value.
3.25
r.m.s. voltage refreshed each cycle
U
rms(1)
value of the r.m.s. voltage measured over 1 cycle and refreshed each cycle
NOTE 1 In contrast to U , this technique does not define when a cycle commences.
rms(1/2)
NOTE 2 This value is used only for voltage dip, voltage swell and interruption detection and evaluation, in Class S.
NOTE 3 This r.m.s. voltage value can be a phase-to-phase value or a phase-to-neutral value.
3.26
range of influence quantities
range of values of a single influence quantity
3.27
reference channel
one of the voltage measurement channels designated as the reference channel for polyphase
measurements
3.28
residual voltage
U
res
or U recorded during a voltage dip or interruption
minimum value of U
rms(1/2) rms(1)
NOTE The residual voltage is expressed as a value in volts, or as a percentage or per unit value of U . U is
din rms(1/2)
used for Class A. Either U or U may be used for Class S. See 5.4.1.
rms(1/2) rms(1)
3.29
sliding reference voltage
U
sr
voltage magnitude averaged over a specified time interval, representing the voltage preceding
a voltage-change type of event (e.g. voltage dips and swells, rapid voltage changes)
– 12 – 61000-4-30 © IEC:2008
3.30
swell threshold
voltage magnitude specified for the purpose of detecting the start and the end of a swell
3.31
time aggregation
combination of several sequential values of a given parameter (each determined over identical
time intervals) to provide a value for a longer time interval
NOTE Aggregation in this standard always refers to time aggregation.
3.32
underdeviation
the absolute value of the difference between the measured value and the nominal value of a
parameter, only when the value of the parameter is lower than the nominal value
3.33
voltage dip
temporary reduction of the voltage magnitude at a point in the electrical system below a
threshold
NOTE 1 Interruptions are a special case of a voltage dip. Post-processing may be used to distinguish between
voltage dips and interruptions.
NOTE 2 A voltage dip is also referred to as sag. The two terms are considered interchangeable; however, this
standard will only use the term voltage dip.
3.34
voltage swell
temporary increase of the voltage magnitude at a point in the electrical system above a
threshold
3.35
voltage unbalance
condition in a polyphase system in which the r.m.s. values of the line voltages (fundamental
component), and/or the phase angles between consecutive line voltages, are not all equal
[IEV 161-08-09, modified]
NOTE 1 The degree of the inequality is usually expressed as the ratios of the negative- and zero-sequence
components to the positive-sequence component.
NOTE 2 In this standard, voltage unbalance is considered in relation to 3-phase systems.
4 General
4.1 Classes of measurement methods
For each parameter measured, three classes (A, S and B) are defined. For each class,
measurement methods and appropriate performance requirements are included.
– Class A
This class is used where precise measurements are necessary, for example, for contractual
applications that may require resolving disputes, verifying compliance with standards, etc.
Any measurements of a parameter carried out with two different instruments complying with
the requirements of Class A, when measuring the same signals, will produce matching
results within the specified uncertainty for that parameter.
61000-4-30 © IEC:2008 – 13 –
– Class S
This class is used for statistical applications such as surveys or power quality assessment,
possibly with a limited subset of parameters. Although it uses equivalent intervals of
measurement as class A, the class S processing requirements are lower.
– Class B
This class is defined in order to avoid making many existing instruments designs obsolete.
NOTE Class B methods are not recommended for new designs. Readers are advised that Class B may be
removed in a future Edition of this standard.
For each class, the range of influencing factors that shall be complied with is specified in
Clause 6. Users shall select the class that they require, based on their application(s).
NOTE 1 The instrument manufacturer should declare influence quantities which are not expressly given and which
may degrade performance of the instrument. Guidance can be found, for example, in IEC 61557-12.
NOTE 2 An instrument may measure some or all of the parameters identified in this standard, and preferably uses
the same class for all parameters.
NOTE 3 The instrument manufacturer should declare which parameters are measured, which class is used for
each parameter, the range of U for which each class is fulfilled, and all the necessary requirements and
din
accessories (synchronization, probes, calibration period, temperature ranges, etc.) to meet each class.
NOTE 4 In this standard, “A” stands for “Advanced”, and “S” stands for “Surveys”. (“B” or “Basic” methods are not
recommended for new designs, because Class B may be removed in a future Edition of this standard.)
4.2 Organization of the measurements
The electrical quantity to be measured may be either directly accessible, as is generally the
case in low-voltage systems, or accessible via measurement transducers.
The whole measurement chain is shown in Figure 1.
Measurement
Measurement
Evaluation
transducers
unit
unit
Electrical input Input signal to Measurement Measurement
signal result evaluation
be measured
IEC 1593/08
Figure 1 – Measurement chain
An instrument may include the whole measurement chain (see Figure 1). In this standard, the
normative part does not consider the measurement transducers external to the instrument and
their associated uncertainty, but Clause A.3 gives guidance.
4.3 Electrical values to be measured
Measurements can be performed on single-phase or polyphase supply systems. Depending on
the context, it may be necessary to measure voltages between phase conductors and neutral
(line-to-neutral) or between phase conductors (line-to-line) or between phase conductors or
neutral and earth (phase-to-earth, neutral-to-earth). It is not the purpose of this standard to
impose the choice of the electrical values to be measured. Moreover, except for the
measurement of voltage unbalance, which is intrinsically polyphase, the measurement methods
specified in this standard are such that independent results can be produced on each
measurement channel.
Phase-to-phase instantaneous values can be measured directly or derived from instantaneous
phase-to-neutral measured values.
– 14 – 61000-4-30 © IEC:2008
Current measurements can be performed on each conductor of supply systems, including the
neutral conductor and the protective earth conductor.
NOTE It is often useful to measure current simultaneously with voltage and to associate the current
measurements in one conductor with voltage measurements between that conductor and a reference conductor,
such as an earth conductor or a neutral conductor.
4.4 Measurement aggregation over time intervals
The following measurement aggregations apply:
– Class A
The basic measurement time interval for parameter magnitudes (supply voltage, harmonics,
interharmonics and unbalance) shall be a 10-cycle time interval for a 50 Hz power system
or 12-cycle time interval for a 60 Hz power system.
The 10/12-cycle measurement shall be re-synchronized at every RTC 10 min tick. See
Figure 2.
NOTE 1 The uncertainty of this measurement is included in the uncertainty measurement protocol of each
parameter.
The 10/12-cycle values are then aggregated over 3 additional intervals:
– 150/180-cycle interval (150 cycles for 50 Hz nominal or 180 cycles for 60 Hz nominal),
– 10 min interval,
– 2 h interval.
NOTE 2 In some applications, other time intervals (e.g. 1 min) may be useful. These other time intervals, if
used, should be implemented with an aggregation method that is analogous to a method defined in this
standard (e.g. a 1 min time interval, if used, should be implemented using a method that is analogous to the 10
minute aggregation method).
NOTE 3 Clauses B.1 and B.2 discuss some applications of these aggregation time intervals.
– Class S
Same time intervals as Class A. The 10/12-cycle measurement shall be re-synchronized as
described in Figure 3 and Figure 4.
– Class B
The manufacturer shall specify the number and duration of aggregation time intervals.
4.5 Measurement aggregation algorithm
4.5.1 Requirements
Aggregations shall be performed using the square root of the arithmetic mean of the squared
input values.
NOTE For flicker measurements, the aggregation algorithm is different (see IEC 61000-4-15).
4.5.2 150/180 cycle aggregation
– Class A
The data for the 150/180-cycle time interval shall be aggregated without gap from fifteen
10/12-cycle time intervals.
The 150/180-cycle time interval is resynchronized upon the 10 min tick as shown in
Figure 2.
When a 10 min tick occurs, a new 150/180-cycle time interval begins, and the pending
150/180-cycle time interval also continues until it is completed. This may create an overlap
between these two 150/180-cycles intervals (overlap 2 in Figure 2).
61000-4-30 © IEC:2008 – 15 –
– Class S
The data for the 150/180-cycle time interval shall be aggregated from 10/12-cycle time
intervals. Resynchronization with the 10 min tick is permitted but not required. (See
Figure 3).
Gaps are permitted but not required for harmonics, interharmonics, mains signalling voltage
and unbalance. A minimum of three 10/12-cycle values shall be used each 150/180-cycle
time interval, furthermore at least one 10/12-cycle value shall be used each 50/60 cycles
(See Figure 4). For all other parameters, the data for the 150/180-cycle time interval shall
be aggregated without gap from fifteen 10/12-cycle time intervals.
– Class B
The manufacturer shall specify the method of aggregation.
4.5.3 10 min aggregation
– Class A
The 10 min aggregated value shall be tagged with the absolute time (for example,
01H10.00). The time tag is the time at the conclusion of the 10 min aggregation.
The data for the 10 min time interval shall be aggregated without gaps from 10/12-cycle
time intervals.
Each 10 min interval shall begin on an RTC 10 min tick. The 10 min tick is also used to re-
synchronize the 10/12-cycle intervals and the 150/180-cycle intervals. See Figure 2.
The final 10/12-cycle interval(s) in a 10 min aggregation period will typically overlap in time
with the RTC 10 min clock tick. Any overlapping 10/12-cycle interval (overlap 1 in Figure 2)
is included in the aggregation of the previous 10 min interval.
IEC 1594/08
Figure 2 – Synchronization of aggregation intervals for Class A
– Class S
The 10 min aggregation method used for class S shall be either the class A method, or the
following simplified method.
– 16 – 61000-4-30 © IEC:2008
A new 10 min time interval shall commence after a 10 min tick occurs, at the beginning of
the next 10/12 cycle time interval.
The data for the 10 min time interval shall be aggregated from 10/12-cycle time intervals.
There is no resynchronization on the 10 min tick. The 10 min intervals are free running.
The 10 min aggregated value shall be tagged with the absolute time. The time tag is the
time at the conclusion of the 10 min interval.
There will be no overlap, as illustrated in Figure 3 and Figure 4.
IEC 1595/08
Figure 3 – Synchronization of aggregation intervals for class S:
parameters for which gaps are not permitted
61000-4-30 IEC:2008 – 17 –
©
GAP
RTC
10 min tick
10 min interval (x + 1)
10 min interval (x)
10/12 cycles GAP 10/12 cycles GAP 10/12 cycles
10/12 cycles GAP
150/180 cycle time interval (n)
150/180 cycle time interval (n + 1)
IEC 1596/08
Figure 4 – Synchronization of aggregation intervals for class S: parameters for which gaps are permitted (see 4.5.2)
NOTE The mains frequency may be either higher or lower than expected. In the example shown in Figure 3, the frequency is lower than expected, so the 150/180 cycle interval
continues beyond the 10 min tick. In the example shown in Figure 4, the frequency is higher than expected and/or there are gaps, so the 150/180 cycle interval concludes before the
10 min tick.
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