BRITISH STANDARD

Electromagnetic
compatibility (EMC) —
Part 4-28: Testing and measurement
techniques — Variation of power
frequency, immunity test for
equipment with input current not
exceeding 16 A per phase

ICS 33.100.20

12&23<,1*:,7+287%6,3(50,66,21(;&(37$63(50,77('%<&23<5,*+7/$:

BS EN
61000-4-28:2000
+A2:2009


BS EN 61000-4-28:2000+A2:2009

National foreword
This British Standard is the UK implementation of
EN 61000-4-28:2000+A2:2009. It is identical with IEC 61000-4-28:1999,
incorporating amendments 1:2001 and 2:2009. It supersedes
BS EN 61000-4-28:2000+A1:2004, which will be withdrawn on 1 March 2012.
The start and finish of text introduced or altered by amendment is indicated
in the text by tags. Tags indicating changes to IEC text carry the number of
the IEC amendment. For example, text altered by IEC amendment 1 is
indicated by !".
The UK participation in its preparation was entrusted by Technical

Committee GEL/210, EMC-Policy committee, to Subcommittee GEL/210/12,
EMC basic, generic and low frequency phenomena Standardization.
A list of organizations represented on this subcommittee can be obtained on
request to its secretary.
This publication does not purport to include all the necessary provisions of a
contract. Users are responsible for its correct application.
Compliance with a British Standard cannot confer immunity from
legal obligations.

This British Standard was
published under the authority
of the Standards Committee
and comes into effect
on 15 June 2000

Amendments/corrigenda issued since publication
Amd. No.

Date

Comments

15275

26 July 2004

Implementation of IEC amendment 1:2001
with CENELEC endorsement A1:2004

31 August

2009

Implementation of IEC amendment 2:2009
with CENELEC endorsement A2:2009

© BSI 2009

ISBN 978 0 580 61451 4


EUROPEAN STANDARD

EN 61000-4-28:2000+A2

NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2009
ICS 33.100.20

English version

Electromagnetic compatibility (EMC) —
Part 4-28: Testing and measurement techniques —
Variation of power frequency, immunity test
for equipment with input current not
exceeding 16 A per phase
(IEC 61000-4-28:1999)

Compatibilité électromagnétique (CEM)
Partie 4-28: Techniques d’essai et de

mesure — Essai d’immunité à la variation
de la fréquence d’alimentation
(CEI 61000-4-28:1999)

Elektromagnetische Verträglichkeit (EMV)
Teil 4-28: Prüf- und Messverfahren —
Prüfung der Störfestigkeit gegen
Schwankungen der energietechnischen
Frequenz (Netzfrequenz)
(IEC 61000-4-28:1999)

This European Standard was approved by CENELEC on 2000-01-01. CENELEC
members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard 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 European Standard 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, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization

Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B-1050 Brussels
© 2000 — All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61000-4-28:2000 E


BS EN 61000-4-28:2000+A2:2009
EN 61000-4-28:2000+A2:2009

Foreword
The text of document 77A/287/FDIS, future edition
1 of IEC 61000-4-28, 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 EN 61000-4-28 on 2000-01-01.
The following dates were fixed:
— latest date by which the EN
has to be implemented at
national level by publication
of an identical national
standard or by endorsement (dop) 2000-10-01
— latest date by which
national standards
conflicting with the EN
have to be withdrawn
(dow) 2003-01-01
Annexes designated “normative” are part of the
body of the standard.

Annexes designated “informative” are given for
information only.
In this standard, Annex ZA is normative and
Annexes A and B are informative.
Annex ZA has been added by CENELEC.

Endorsement notice
The text of the International Standard
IEC 61000-4-28:1999 was approved by CENELEC
as a European Standard without any modification.

Foreword to amendment A1
The text of amendment 1:2001 to the International
Standard IEC 61000-4-28:1999, prepared by
SC 77B, High frequency phenomena, of IEC TC 77,
Electromagnetic compatibility, was submitted to
the Unique Acceptance Procedure and was approved
by CENELEC as amendment A1 to
EN 61000-4-28:2000 on 2004-04-01 without any
modification.
The following dates were fixed:

2

— latest date by which the
amendment has to be
implemented at national
level by publication of an
identical national standard
or by endorsement

(dop) 2005-05-01
— latest date by which
national standards
conflicting with the
amendment have to be
withdrawn
(dow) 2007-05-01

Endorsement notice
The text of the amendment 1:2001 to the
International Standard IEC 61000-4-28:1999 was
approved by CENELEC as an amendment to the
European Standard without any modification.

Foreword to amendment A2
The text of document 77A/673/FDIS, future
amendment 2 to IEC 61000-4-28:1999, 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
A2 to EN 61000-4-28:2000 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

Endorsement notice
The text of amendment 2:2009 to the
International Standard IEC 61000-4-28:1999 was
approved by CENELEC as an amendment to the
European Standard without any modification.

© BSI 2009


Page 3

BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000 +A2:2009
C
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Table


Page 4


BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

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 Standard,
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.



Page 5

BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4-28: Testing and measurement techniques –
Variation of power frequency, immunity test for
equipment with input current not exceeding 16 A per phase
1

Scope

This part of IEC 61000 is a basic EMC (electromagnetic compatibility) publication. It considers
immunity tests for electric and/or electronic equipment in its electromagnetic environment. Only
conducted phenomena are considered, including immunity tests for equipment connected to
public and industrial networks.
The object of this part is to establish a reference for evaluating the immunity of electric and
electronic equipment when subjected to variations of the power frequency.
This standard applies to electric and/or electronic equipment connected to 50 Hz or 60 Hz
distributed network with rated line current up to 16 A per phase.
It does not apply to electric and/or electronic equipment connected to a.c. 400 Hz distribution
networks. Tests concerning these networks will be covered by other IEC standards.
In general, electrical and electronic equipment is not susceptible to minor variations of the
power frequency. Testing according to this standard should be limited to products which are
assessed to be susceptible to power frequency variations by virtue of design, environment or
failure consequences.
The immunity test levels required for a specific electromagnetic environment together with the
performance criteria are indicated in the product, product family or generic standards as

applicable.

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 Electromagnetic compatibility
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 61000-2-4, Electromagnetic compatibility (EMC) – Part 2: Environment – Section 4: Compatibility levels in industrial plants for low-frequency conducted disturbances


Page 6

BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

3

General

The purpose of the test is to investigate effects of power frequency variations on equipment
which may be sensitive to this disturbance. The effects are generally instantaneous.
Electrical and electronic equipment may be affected by variations of the power frequency.
The frequency of a.c. power derived from public systems is directly related to the rotational
speed of the generators, as is the frequency of a.c. power derived from an alternator which is
separate from the public network. The frequency depends at any instant on the dynamic
balance between the loads and the capacity of the generating plants. Consequently, as this

dynamic balance changes, small changes in frequency will occur. The size and duration of
these changes depends on the characteristics of the load changes and response of the
generating plant to the load changes. Where the supply is derived from an independent
inverter, the frequency may be derived from the control circuitry and is then fixed.
The frequency of public systems is, under normal conditions, generally declared by the supplier
in terms of a nominal value (50 Hz or 60 Hz) with a small bandwidth within which these
changes in frequency will normally be limited. However, in non-interconnected systems (small
networks isolated like islands), variations of frequency are likely to be greater and
consequently more important.
Frequency variations can affect
–

control systems referring to time (measurement errors, loss of synchronization, etc.);

–

equipment including passive filter (de-tuned).

4

Definitions

For the purposes of this part of IEC 61000, the following definitions and terms apply as well as
the definitions of IEC 60050(161).
4.1
immunity
ability of a device, equipment or system to perform without degradation in the presence of an
electromagnetic disturbance [IEV 161-01-20]
4.2
malfunction

termination of the ability of an equipment to carry out intended functions or the execution of
unintended functions by the equipment

5

Test levels

The test is performed at nominal mains voltage.
The equipment under test (EUT) is initially in operation at a mains frequency f 1 and is then
subjected to frequency variation sequence according to figure 1.
Df/f 1 is specified as a percentage of nominal frequency f 1 .


Page 7

BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

Test values are specified in table 1.
Table 1 – Test levels for frequency variations
Test levels

Frequency variation (∆
∆ f/f 1 )

Transitional period t p

Level 1

No test required


No test required

Level 2

±3 %

10 s

Level 3

+4 %
–6 %

10 s

Level 4

±15 %

1s

Level X

Open

Open

During the transitional period, t p , (figure 2), the maximum change in frequency per cycle shall
be less than 0,5 % of f 1 .

Levels 1 and 2 are specified for equipment in relation to class 1 and 2 in IEC 61000-2-4
respectively (see annex B).
Levels 3 and 4 are specified for equipment of which the misoperation is critical for specific
application. These two test levels cover the frequency variations 100 % of the week.
Level 3 is specified for interconnected networks and level 4 is specified for non-interconnected
networks.
X is an open test level. All of the levels can be proposed by a product committee, however, the
value shall not be less than level 2 for equipment connected to public networks
NOTE The upper and the lower frequency operation limits defined by the product manufacturer should not,
however, be exceeded.

6
6.1

Test equipment
Test generators: characteristics and performances

The generator shall have provisions to prevent the emission of heavy disturbances which, if
injected in the power supply network, may influence the test results.
Table 2 – Characteristics of the generator
Output voltage accuracy

±2 %

Output voltage and current capability

The generator shall be able to supply enough voltage
and current according to the type of EUT

Phase accuracy for each phase


2° (0,5 % of 360°)

Frequency accuracy

0,3 % of f 1 (50 Hz or 60 Hz)

Frequency capability range

f 1 ± 20 %

Test duration accuracy

±10 %

# 6.2

Verification of the characteristics

It is recognized that there is a wide range of EUTs, and that consequently test generators with
different output power capabilities may be utilized, as required by particular tests.$


Page 8

BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

# It shall be verified that the test generator meets the characteristics and performance
specifications as listed in Table 2.

Performance of the test generator shall be verified with a resistive load drawing an r.m.s.
current of no more than the output capability of the generator. For example, a 230V/16A
generator shall be verified with a 14,3 Ω load.
In addition, the generator’s output current capability shall be verified as being able to provide
a crest factor of at least 3 when U N is applied to a single phase load drawing an rms current
of no more than the output capability of the generator. Each output phase of the generator
shall be verified in turn. An example of a 230 V/16 A verification load is given in Figure 4. $

7

Test set-up

Figure 3 shows the test configuration for mains supply simulation.
Waveform generators and power amplifiers are used.
Tests on the threephase EUT are accomplished by using generators with synchronization
between each phase.

8

Test procedure

Before starting the test of a given equipment, a test plan shall be prepared.
It is recommended that the test plan shall identify the following:
–

the type designation of the EUT;

–

information on possible connections (plugs, terminals, etc.) and corresponding cables and

peripherals;

–

input power port of equipment to be tested;

–

representative operational modes of the EUT for the test;

–

performance criteria used and defined in the technical specifications;

–

description of the test set-up.

If the actual operating signal sources are not available to the EUT, they may be simulated.
For each test, any degradation of performance shall be recorded. The monitoring equipment
should be capable of displaying the status of the operational mode of the EUT during and after
the tests. After the test, a representative functional check shall be performed.

! 8.1

Climatic conditions

Unless otherwise specified by the committee responsible for the generic or product standard,
the climatic conditions in the laboratory shall be within any limits specified for the operation of
the EUT and the test equipment by their respective manufacturers.

Tests shall not be performed if the relative humidity is so high as to cause condensation on the
EUT or the test equipment.
NOTE Where it is considered that there is sufficient evidence to demonstrate that the effects of the phenomenon
covered by this standard are influenced by climatic conditions, this should be brought to the attention of the
committee responsible for this standard."


Page 9

BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

8.2

Execution of the test

The EUT shall be tested using the appropriate test level. Each test shall be performed three
times according to figure 2. Each representative mode of operation shall be tested.
For the three-phase system, all three phases shall be tested simultaneously. The frequency
variation is applied simultaneously on the three phases.

!9

Evaluation of test results

The test results shall be classified in terms of the loss of function or degradation of
performance of the equipment under test, relative to a performance level defined by its
manufacturer or the requestor of the test, or agreed between the manufacturer and the
purchaser of the product. The recommended classification is as follows:
a) normal performance within limits specified by the manufacturer, requestor or purchaser;

b) temporary loss of function or degradation of performance which ceases after the
disturbance ceases, and from which the equipment under test recovers its normal
performance, without operator intervention;
c) temporary loss of function or degradation of performance, the correction of which requires
operator intervention;
d) loss of function or degradation of performance which is not recoverable, owing to damage
to hardware or software, or loss of data.
The manufacturer’s specification may define effects on the EUT which may be considered
insignificant, and therefore acceptable.
This classification may be used as a guide in formulating performance criteria, by committees
responsible for generic, product and product-family standards, or as a framework for the
agreement on performance criteria between the manufacturer and the purchaser, for example
where no suitable generic, product or product-family standard exists.

10 Test report
The test report shall contain all the information necessary to reproduce the test. In particular,
the following shall be recorded:
– the items specified in the test plan required by clause 8 of this standard;
– identification of the EUT and any associated equipment, for example, brand name, product
type, serial number;
– identification of the test equipment, for example, brand name, product type, serial number;
– any special environmental conditions in which the test was performed, for example, shielded
enclosure;
– any specific conditions necessary to enable the test to be performed;
– performance level defined by the manufacturer, requestor or purchaser;
– performance criterion specified in the generic, product or product-family standard;
– any effects on the EUT observed during or after the application of the test disturbance, and
the duration for which these effects persist;
– the rationale for the pass/fail decision (based on the performance criterion specified in the
generic, product or product-family standard, or agreed between the manufacturer and the

purchaser);
– any specific conditions of use, for example cable length or type, shielding or grounding, or
EUT operating conditions, which are required to achieve compliance."


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BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

f1

f1

tp

f1 + ∆f
120 s

tp

f1
60 s

60 s

tp

f1 − ∆f


tp

f1

120 s

IEC 1588/99

Figure 1 – Frequency variation sequence

f1

tp

f1 + ∆
∆f
IEC

Figure 2 – Example of transitional period t p

1589/99


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BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

One or
three

phases
Controller

Waveform
generator

Power
supply

Power
amplifier
Voltmeter
oscilloscope

EUT

Neutral

IEC 1590/99

Figure 3 – Schema of test instrumentation with power amplifier
Ra

#

B
G
C

+


R

IEC 229/09

Components
G

Test generator

B

Bridge rectifier

C

11 000 μF ± 20 % electrolytic capacitor

R

61 Ω ± 1 % resistor

Ra

Additional resistor

NOTE R a is selected so that the total series resistance (sum of the additional resistor R a , the wiring resistance
R wire , the internal resistance of two conducting diodes R diodes and the internal resistance of the capacitor R c ) is
92 mΩ (±10 %).


Figure 4 – Example of test generator verification load $


Page 12

BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

Annex A
(informative)
Sources and effects of variation of the power frequency

A.1

Sources

In public supply systems, there is normally an excess of capacity over load demand in order to
maintain frequency changes within the declared bandwidth. However, rare fault conditions may
arise under which, for example, a large block of load or generation is disconnected with a
resultant change in frequency outside the normal tolerance band. In such cases, some of the
load or generation will be automatically or manually disconnected to restore the balance as far
as possible.
Rotating loads which are not speed-controlled usually take less power at a lower frequency so
that loss of generation may to some extent be compensated by lower demand.

A.2

Effects

Within the normal tolerances encountered, the main effect of a change in power frequency is

on the speed of rotation machines. Hence, mains electrical clocks will lose or gain time and
other motors will deliver more or less power, the change depending on the speed/torque
relationship of the load. Power frequency variation may have a de-tuning effect on harmonic
filters.
Any electronic equipment using the power supply frequency as a time reference will also be
affected.


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BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009

Annex B
(informative)
Electromagnetic environment classes

The following classes of electromagnetic environment classes have been summarized from
IEC 61000-2-4.

Class 1
This class applies to protected supplies and has compatibility levels lower than public network
levels. It relates to the use of equipment which is very sensitive to disturbances in the power
supply, for instance the instrumentation of technological laboratories, some automation and
protection equipment, some computers, etc.
NOTE Class 1 environments normally contain equipment which requires protection by such apparatus as
uninterruptible power supplies (UPS), filters, or surge suppressors.

Class 2
This class applies to points of common coupling (PCCs for consumer systems) and in-plant

points of common coupling (IPCs) in the industrial environment in general. The compatibility
levels in this class are identical to those of public networks; therefore components designed for
application in public networks may be used in this class of industrial environment.

Class 3
This class applies only to IPCs in industrial environments. It has higher compatibility levels than
those of class 2 for some disturbance phenomena. For instance, this class should be
considered when any of the following conditions are met:
–

a major part of the load is fed through converters;

–

welding machines are present;

–

large motors are frequently started;

–

loads vary rapidly.

NOTE 1 The supply to highly disturbing loads, such as arc-furnaces and large converters which are generally
supplied from a segregated busbar, frequently has disturbance levels in excess of class 3 (harsh environment). In
such special situations, the compatibility levels should be agreed upon.
NOTE 2 The class applicable for new plants and extensions of existing plants should relate to the type of
equipment and process under consideration.


____________


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BS EN 61000-4-28:2000+A2:2009
EN 61000−4−28:2000+A2:2009


blank


BS EN
61000-4-28:2000
+A2:2009

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