SIST-TP IEC TR 61000-3-18:2025

IEC TR 61000-3-18 ®
Edition 1.0 2024-02
TECHNICAL
REPORT
colour
inside
Electromagnetic compatibility (EMC) –
Part 3-18: Limits – Assessment of network characteristics for the application of
harmonic emission limits – Equipment connected to LV distribution systems not
covered by IEC 61000-3-2 and IEC 61000-3-12

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IEC TR 61000-3-18 ®
Edition 1.0 2024-02
TECHNICAL
REPORT
colour
inside
Electromagnetic compatibility (EMC) –

Part 3-18: Limits – Assessment of network characteristics for the application of

harmonic emission limits – Equipment connected to LV distribution systems

not covered by IEC 61000-3-2 and IEC 61000-3-12

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.100.10  ISBN 978-2-8322-8219-9

– 2 – IEC TR 61000-3-18:2024 © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 10
4 General . 10
5 State of existing IEC standards . 12
5.1 Overview of existing standards . 12
5.2 Voltage gaps . 12
5.3 Frequency gaps . 13
5.4 System impedance considerations . 13
6 General approach . 14
7 Detailed implementation of the methodology . 15
7.1 Overview. 15
7.2 European reference network model (RNM) . 15
7.2.1 History . 15
7.2.2 Adjusted RNM for assessing harmonic sensitivity . 16
7.3 Harmonic current model . 18
7.4 Methodology for adapting IEC equipment harmonic emission limits . 20
7.4.1 General . 20
7.4.2 Conversion factor (C ) . 21
fh
7.5 Sensitivity ratio S . 22
R
8 Simulation considerations . 22
8.1 Overview. 22
8.2 Simulation model adjustment . 23
8.3 Studies with only the maximum harmonic distortion of each feeder . 23
8.4 Sampling the feeders of the entire power system . 24
9 Statistical analysis . 24
10 Conclusions . 25
Annex A (informative) Other methods studied for comparing feeder harmonic
sensitivity. 27
A.1 General . 27
A.2 Voltage droop . 27
A.2.1 Explanation . 27
A.2.2 Voltage droop simulation . 27
A.2.3 Concept of the voltage droop approach . 28
A.2.4 Validation of the voltage droop method . 29
A.2.5 Clustering . 30
A.2.6 Feeder parameters . 33
Annex B (informative) Power distribution systems in Canada . 36
B.1 Overview. 36
B.2 Conversion factor . 37
Annex C (informative) Power distribution systems in Japan . 40

C.1 Background for harmonics limits . 40
C.2 Outlook on a typical distribution system in Japan . 40
C.3 Power supply to customers in Japan . 42
C.4 Distribution system impedance in Japan . 42
th
C.5 Case study of 95 percentile and conversion factor in Japan . 43
th
C.6 Comparing the 95 percentile distortion level of Japan vs. EU RNM . 43
Annex D (informative) Example of a Python script used with CYMDIST software . 46
Bibliography . 57

Figure 1 – Reference network medium-voltage power system . 17
Figure 2 – LV network of 153 customers supplied by a 400 kVA transformer . 17
rd th
Figure A.1 – Scatter plot of voltage harmonic levels (3 and 5 ) as function of the
voltage droop . 28
th
Figure A.2 – Comparison of the 95 percentile harmonic levels obtained from
simulation and calculated from the voltage droop . 30
Figure A.3 – q = 1, Manhattan distance . 31
Figure A.4 – q = 2, Euclidian distance . 31
Figure A.5 – Two-parameter k-means clustering example . 32
Figure A.6 – Illustration of SSE . 33
Figure A.7 – Harmonic distortion levels at cluster centroids . 35
Figure B.1 – Low-voltage system in Canada . 36
Figure B.2 – Multi-unit building of 32 customers . 37
Figure B.3 – Buildings with > 1 000 residential customers . 37
Figure C.1 – Overview of the power system in Japan [11] . 41
Figure C.2 – Standard neutral grounding systems for HV and MV distribution system in
Japan . 41
Figure C.3 – Distribution transformer for HV/MV in Japan . 41
Figure C.4 – Popular LV distribution systems in Japan . 42

Table 1 – Modelled RNM voltage distortion compared with compatibility levels . 18
th
Table 2 – 5 harmonic current (h5) per household proposed by [4] . 19
th
Table 3 – 7 harmonic current (h7) per household proposed by [4] . 19
Table 4 – Harmonic load injection at each customer POI in the modelled network . 20
Table 5 – Creating the cumulative data function . 25
Table A.1 – Coefficients of linear regression obtained from the harmonic and droop data . 29
Table B.1 – LV feeder impedance in Canada . 36
Table B.2 – Data for assessing the Canada 240 V limits . 38
Table B.3 – Limits for Class A Equipment . 39
Table C.1 – Impedance survey results for MV distribution lines (Ω) . 42
Table C.2 – Results of long-range survey of MV distribution lines (km) . 43
Table C.3 – Impedance survey results for LV distribution lines (mΩ) . 43
Table C.4 – Data and calculated limits at 100 V in Japan . 44

– 4 – IEC TR 61000-3-18:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 3-18: Limits – Assessment of network characteristics
for the application of harmonic emission limits – Equipment
connected to LV distribution systems not covered
by IEC 61000-3-2 and IEC 61000-3-12

FOREWORD
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IEC TR 61000-3-18 has been prepared by subcommittee 77A: EMC – Low frequency
phenomena, of IEC technical committee 77: Electromagnetic compatibility. It is a Technical
Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
77A/1197/DTR 77A/1202/RVDTR
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 Technical Report 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
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 61000 series, published under the general title Electromagnetic
compatibility (EMC), can be found on the IEC website.
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, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

– 6 – IEC TR 61000-3-18:2024 © IEC 2024
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 levels
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 a second
number identifying the subdivision (example: IEC 61000-6-1).

ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 3-18: Limits – Assessment of network characteristics
for the application of harmonic emission limits – Equipment
connected to LV distribution systems not covered
by IEC 61000-3-2 and IEC 61000-3-12

1 Scope
This part of IEC 61000, which is a technical report, reports on the development of a methodology
for adapting IEC equipment emission limits from IEC 61000-3-2 and IEC 61000-3-12 for use in
regions not covered by these documents. It identifies gaps in the existing equipment emission
limit standards concerning their international applicability and identifies public power system
characteristics important for the evaluation of harmonic voltage performance.
The purpose of adapting the above-mentioned IEC equipment harmonic emission standards in
a particular region is to maintain similar electromagnetic compatibility (EMC) of equipment up
to 75 A per phase in the public power systems in those regions.
NOTE The boundaries between the various voltage levels differ amongst different countries
(see IEC 60050-601:1985, 601-01-28). This document uses the following terms when referring to 50 Hz and 60 Hz
system voltages:
– low voltage (LV) refers to U ≤ 1 kV;
n
– medium voltage (MV) refers to 1 kV < U ≤ 35 kV;
n
– high voltage (HV) refers to 35 kV < U ≤ 230 kV.
n
EMC requirements can have economic and societal impacts; these have not been considered
in the development of this document. The consideration of these factors generally occurs in the
technical committees working on development and maintenance of emission limit standards.
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

– 8 – IEC TR 61000-3-18:2024 © IEC 2024
3.1 Terms and definitions
3.1.1
distribution system operator
DSO
party operating an electric power distribution system
[SOURCE: IEC 60050-617:2009, 617-02-10, modified – electric power has been added to the
definition.]
3.1.2
distributed energy resource
DER
generator (with its auxiliaries, protection and connection equipment), including loads having a
generating mode (such as electrical energy storage systems), connected to a low-voltage or a
medium-voltage network
[SOURCE: IEC 60050-617:2017, 617-04-20, modified – changed to singular]
3.1.3
electromagnetic compatibility
EMC
ability of equipment or a system to function satisfactorily in its electromagnetic environment
without introducing intolerable electromagnetic disturbances to anything in that environment
[SOURCE: IEC 60050-161:2018, 161-01-07]
3.1.4
(electromagnetic) compatibility level
the specified electromagnetic disturbance level used as a reference level for co-ordination in
the setting of emission and immunity limits
Note 1 to entry: By convention, the compatibility level is chosen so that there is only a small probability that it will
be exceeded by the actual disturbance level. However electromagnetic compatibility is achieved only if emission and
immunity levels are controlled such that, at each location, the disturbance level resulting from the cumulative
emissions is lower than the immunity level for each device, equipment and system situated at this same location.
Note 2 to entry: The compatibility level can be phenomenon, time or location dependent.
[SOURCE: IEC 60050-161:1990, 161-03-10]
3.1.5
emission limit (of a disturbing source)
specified maximum permitted emission of a source of electromagnetic disturbance
3.1.6
electric power network
network
particular installations, substations, lines or cables for the transmission and distribution of
electricity
Note 1 to entry: Electric power network can also be referred to as electric power system (system).
[SOURCE: IEC 60050-601:1985, 601-01-02]
3.1.7
harmonic (component)
component of order greater than 1 of the Fourier series of a periodic quantity
[SOURCE: IEC 60050-161:1990, 161-02-18]

3.1.8
point of connection
point of interconnection
POC
POI
reference point on the electric power system where the user’s electrical facility is connected
[SOURCE: IEC 60050-617:2009, 617-04-01, modified – in the term “point of connection” and
“POI” have been added.]
3.1.9
point of common coupling
PCC
point of a power supply network, electrically nearest to a particular load, at which other loads
are, or can be, connected
Note 1 to entry: These loads can be either devices, equipment or systems, or distinct customer installations.
Note 2 to entry: In some applications, the term “point of common coupling” is restricted to public networks.
[SOURCE: IEC 60050-161:1990, 161-07-15]
3.1.10
reference network model
RNM
th
95 percentile representation of a power system by means of one circuit designed with lines,
cables, equipment, and loads having specified configurations for an intended study
th
Note 1 to entry: A reference network model for obtaining the 95 percentile of steady-state voltage performance
th
might be different from a reference network model for obtaining the 95 percentile of voltage harmonic distortion.
3.1.11
network sensitivity
ratio of change produced in a network variable by injection of a known disturbance
Note 1 to entry: The change in harmonic distortion level in a network by injection of harmonic current is one example
of sensitivity that can be used for comparative purposes.
3.1.12
system impedance
impedance of the supply system as viewed from the point of common coupling
[SOURCE: IEC 60060-161:1990, 161-07-16, modified – “supply” has been removed from the
term.]
3.1.13
topology
relative position of the ideal elements representing an electric
network.
[SOURCE: IEC 60050-603:1986, 603-02-04]

– 10 – IEC TR 61000-3-18:2024 © IEC 2024
3.2 Abbreviated terms
C Conversion factor
fh
th
CP95 95 percentile
DER Distributed energy resource
DSO Distribution system operator
EMC Electromagnetic compatibility
h Harmonic of order
LV Low voltage
MV Medium voltage
HV High voltage
NA North America
PCC Point of common coupling
POC Point of connection
POI Point of interconnection
RNM Reference network model
th
S 95 percentile of the harmonic voltage at the POIs of the RNM
h
RNM
th
S 95 percentile of the harmonic voltage at the POIs of the targeted network
h
Target
S Sensitivity ratio
R
SSE Sum-squared error
SWER Single-wire earth-return
THD Total harmonic distortion
U Supply voltage for the new limits
NEW
U Voltage ratio
R
U Phase-to-neutral European voltage, which is 230,94 V computed from the phase-
RNM
phase nominal voltage, which is 400 V
xPyW x-phase y-wire where x and y are numeric
4 General
IEC documents defining equipment harmonic current emission limits are largely based on
European power systems having three-phase three-wire (3P3W) MV feeder topologies
supplying three-phase four-wire (3P4W) LV distribution networks through delta-wye
transformation. Typically, such LV systems serve hundreds of customers via many kilometres
of cables, usually in a grounded configuration. This feeder topology results in a significant
portion of the voltage total harmonic distortion (THD) at any given LV point of interconnection
(POI) being caused by aggregation of harmonic currents flowing through the LV network
impedance.
According to available historical information, existing emission limit studies were based on this
European feeder topology with the knowledge that approximately 25 % of the contribution to
voltage distortion comes from the LV system. Even though the use of delta-wye transformation
effectively blocks zero-sequence harmonics from returning to the MV network, there was no
special consideration given for modelling different sequence harmonics, only h5 (negative
sequence) and h7 (positive sequence) orders were simulated. Historical documents explaining
the method used to establish the emission limits that led to the IEC documents are no longer
available, thus the exact method used at that time is difficult to recover. However, recent field
measurements carried out in European countries have shown that the actual limits are effective
in keeping the harmonic voltage below compatibility levels at most locations. This document
does not redefine the approach used to establish emission limits. The objective is to report an
appropriate methodology to adapt the existing limits in order to reproduce, for other countries,
the same performance as observed in European countries.
Numerous power system topologies exist around the world that have characteristics differing
from the 3P3W MV distribution systems used in Europe, which supply a small number of large
MV/LV transformer stations. The following are examples of regions having power systems
sufficiently different from those of Europe; adaptation of IEC emission limits can be beneficial
for them in pursuit of EMC:
• North America: While there are regional differences within North America, generally the MV
networks are 3P4W systems with multi-grounded neutrals. They supply hundreds of small
MV/LV transformers (mixed single-phase and three-phase), and each serves only a few
customers compared to those of Europe which serve hundreds of customers. MV feeders
tend to be significantly longer than in Europe, so shunt capacitors and regulating
transformers installed at various locations along the feeders are used to control the voltage.
Of special note are the 1P3W LV networks supplying 120/240 V service to residential and
other small single-phase customers. The three-phase LV networks used for larger multi-unit
residential buildings, larger commercial, or industrial customers are 3P4W grounded
systems having very short service cables, often less than 100 m in length.
• Japan: The population density in Japan is comparable to that of Europe. The MV system is
significantly shorter than that in North America; its 3P3W MV distribution system operates
at 6,6 kV to supply residential, commercial, and small industrial sectors. Since this MV
system distributes the phase voltage without a neutral conductor, the single-phase LV
systems are powered by transformers connected phase-to-phase. An open-delta
transformer is used when three-phase voltage is required. Unlike in Europe, the connection
of MV/LV transformers allows for triplen harmonics to circulate on the MV network (though
not as zero-sequence components). Since the MV network voltage is about three times
lower than that found in Europe, the number of customers supplied from it is also lower. On
the other hand, an extension of the MV network at 22 kV, like that of Europe, is used to
supply the 6,6 kV power system as well as larger MV customers. As in North America, the
MV/LV transformers supply residential and small commercial customers with two voltages,
however the supply is 100/200 V instead of 120/240 V.
• Australia: The Australian power system might be described as a hybrid topology having
characteristics similar to both European and North American networks. They are similar in
urban environments to Europe where short MV systems supply a few larger MV/LV
transformers which in turn supply many customers in densely populated areas at 230/400
V. However, Australian systems also cover vast open territories using 1P1W MV networks
using earth for return currents, called a single-wire earth-return (SWER) system. These are
like North America in the sense that they serve rural areas using long single-phase
networks, specifically like Canada where some distribution feeders exceed 200 km in length.
However, the SWER system serves very few customers and has a lot of capacitance to
ground due to its long length, thus the Ferranti effect – normally seen on lightly loaded
transmission systems – is a concern here. For this reason, voltage regulation is
implemented using shunt reactors instead of shunt capacitors.

– 12 – IEC TR 61000-3-18:2024 © IEC 2024
Given the physical differences in systems such as impedance, customer density, service
voltage, wiring, and grounding configurations it is reasonable to conclude that such topologies
are impacted differently by harmonic emissions. As such, emission limits might be adjusted
according to the power system capability to maintain the harmonic voltages below the applicable
targets. Consider the following important characteristics that impact harmonic distortion
performance differently:
– North American lower-impedance LV systems served by higher-impedance MV systems
perform differently than European distribution systems in the sense that most of the
harmonic aggregation occurs at the MV level. The harmonic voltage drops at the LV level
due to having shorter cables and fewer customers, and therefore contribution to voltage
THD in each LV network is very small (<< 5 % of voltage THD); when aggregated at the MV
level it becomes apparent that most of the voltage distortion occurs by aggregation of load
currents flowing through the impedance of the MV system (>> 95 % of voltage THD).
– The very long single-wire earth-return (SWER) distribution systems in Australia are
characterized by light loading and high capacitance to ground; thus, shunt inductors are
used to lower the voltage level along the MV lines. The high capacitance of the system in
parallel with these inductors leaves it vulnerable to resonances.
The two examples noted above are causes for uncertainty as regions having different power
system characteristics than Europe adopt the IEC harmonic emission limits without any local
adaptations.
This document reports on the development of design characteristics for a benchmark European
distribution power system that can be used for the purpose of modelling harmonic performance.
The harmonic distortion level of the reference network model (RNM), when used with the
recommended harmonic load, aligns well with present-day IEC compatibility levels. Subclause
7.2 describes in detail the origins of the data used to develop the RNM. A methodology is
described for comparing other distribution systems to the European benchmark system for the
purpose of adapting IEC harmonic current emission limits (IEC 61000-3-2 and IEC 61000-3-12)
for effective use with those networks. The methodology was developed and tested using power
system models from both Canada and Japan. Annex B and Annex C include power system
details and the resulting limits from applying the methodology for both Canada and Japan
respectively.
5 State of existing IEC standards
5.1 Overview of existing standards
IEC 61000-3-2 and IEC 61000-3-12 establish harmonic emission limits for equipment with input
currents ≤16 A per phase and ≤ 75 A per phase, respectively. The limits are intended for
equipment that is connected to the public LV distribution system in attempt to control the voltage
THD in the electromagnetic environment. These standards form one part of the harmonic EMC
framework intended to control harmonic distortion in the environment. When these standards
are adopted in a region, then a baseline distortion level can be expected if these standards
function as intended. DSOs can then enforce further harmonic controls on large customers
through application of IEC TR 61000-3-6, which accounts for the baseline distortion level
controlled by IEC 61000-3-2 and IEC 61000-3-12. The proper application of these standards is
therefore of utmost importance to maintain EMC in the network.
The existing standards were created for European public distribution systems, and as such are
based on characteristics of those systems. This leaves potential gaps with respect to their
applicability in other regions of the world where the characteristics of the public supply systems
differ. The obvious gaps which exist in the standards relate to applicable voltage levels and
frequencies. The less obvious gaps with respect to differing system and sequence impedances
exist because only one network model was used to determine the limits.
5.2 Voltage gaps
IEC 61000-3-2:2018 states the following in 6.1:

“The requirements and limits specified in this document are applicable to the power input
terminals of equipment intended to be connected to 220/380 V, 230/400 V and 240/415 V
systems operating at 50 Hz or 60 Hz. Requirements and limits for other cases are not yet
specified.”
IEC 61000-3-12:2011 states the following in Clause 1, second paragraph:
“The limits given in this edition apply to equipment when connected to 230/400 V, 50 Hz
systems.”
It then goes on to state the following in NOTE 1:
“The limits for the other systems will be added in a future edition of this standard.”
The following voltages, known to be used elsewhere in the world, are presently not mentioned
in the equipment harmonic emission limit standards. This might not represent the whole list of
voltages not previously considered:
Single-phase voltages:
100 V, 110 V, 115 V, 120 V, 127 V, 200 V
Three-phase voltages:
3P4W systems: 100/200 V, 120/208 V, 127/220 V, 277/480 V, 347/600 V
3P3W systems: 190 V, 200 V, 240 V, 440 V, 480 V
5.3 Frequency gaps
The IEC standards are sometimes restricted to 50 Hz supply systems; the 60 Hz power system
frequency is used in many parts of the world:
• 60 Hz supply limits are presently specified in IEC 61000-3-2
• 60 Hz supply limits are not presently specified in IEC 61000-3-12
5.4 System impedance considerations
IEC TR 61000-1-4 provides the historic rationale for the harmonic limits defined in
IEC 61000-3-2 and IEC 61000-3-12. IEC TR 61000-1-4:2022states the following with respect
to network characteristics and rationale for equipment harmonic limits in Clause 1:
“Some concepts in this document apply to all low voltage AC systems, but the numerical values
apply specifically to the European 230 V/400 V 50 Hz system.”

– 14 – IEC TR 61000-3-18:2024 © IEC 2024
IEC TR 61000-1-4:2022, Annex A, Clause A.1 goes on to state the following:
“The typical percentage impedances in European networks are given in Figure A.1. The partition
of the total compatibility level into the parts assigned to each voltage level reflects roughly the
relation of these percentage impedances. In order to account for the geometric summation of
the voltage drops, the value of 25 % for the LV-network is increased with respect to the value
which can be derived from the ratio of the impedance values. 25 % of the total compatibility
level is therefore used in IEC 61000-3-2 and IEC 61000-3-12 for the assessment of the
maximum harmonic currents from non-linear loads in the LV-network for 230 V 50 Hz systems.”
It follows, therefore, that public distribution supply systems in other regions of the world which
are known to have different network characteristics require special consideration when
introducing IEC equipment harmonic current emission limits.
6 General approach
The general approach of this study is to compare the harmonic sensitivity of different power
systems and use the resulting voltage distortion differences to adapt the existing harmonic
current emission limits for application to the target network. Numerous different ways to
characterize networks and model harmonic sensitivity were studied in attempt to find a
simplified approach, one that would provide accurate results and account for all the local
variations that can exist in a power system. Regrettably, studies using voltage droop and
clustering of feeder characteristics did not reveal any promising simplifications that are accurate
enough to be useful; thus detailed harmonic modelling of the target power system in comparison
with the benchmark European system is identified as the most accurate and reliable means of
determining the network’s sensitivity to harmonic current injection.
The methodology presented in this document is based on studies using real power system
models obtained from various DSOs in Europe, North America, and Asia. Modern scripting
techniques included with some modelling software allow for harmonic simulation at every
customer connection point of the whole power system, thereby providing the detailed results
th
that will be used for finding the 95 percentile levels to use for comparative analysis. It is noted
that the methodology aims to evaluate the sensitivity of each electrical network to harmonic
currents rather than to evaluate the real harmonic level that is expected. The harmonic
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sensitivity level is the 95 percentile of the harmonic voltage distortion at all customer POIs in
the target region, given a specific harmonic load injection at each POI.
The tasks undertaken to implement the developed methodology are described in this document;
they are as follows:
a) the European RNM is developed for easy implementation in any power system modelling
software;
b) the harmonic load profile is defined;
c) a scripting interface with power system modelling software is used to assess the harmonic
TM 1
power flow at every POI in the power system. A detailed Python script for use with
CYMDIST models is provided in Annex D for users of that software;
d) the statistical methods for analysing the results are defined;
e) the resulting procedure is the technical basis for translating the IEC equipment harmonic
current emission limits for use in the target network, based on the resulting power system
harmonic sensitivity.
___________
1 Python is the trade name of a product supplied by PythonTM. This information is given for the convenience of
users of this document and does not constitute an endorsement by IEC of the product named. Equivalent products
may be used if they can be shown to lead to the same results.
2 CYMDIST is the trade name of a product supplied by Eaton. This information is given for the convenience of
users of this document and does not constitute an endorsement by IEC of the product named. Equivalent products
may be used if they can be shown to lead to the same results.

The methodology in this document provides only a technical basis for applying limits in regions
not covered by IEC 61000-3-2 and IEC 61000-3-12, with the primary goal of maintaining EMC
equivalent to that which has been achieved in Europe. To complete the process of setting limits
by consensus, in a second step, the impact of suppression measures on physical, operational,
manufacturing and the overall economic aspects will also be considered, and the limits will be
negotiated with all essential parties.
7 Detailed implementation of the methodology
7.1 Overview
According to IEC TR 61000-2-1:1990, Clause 4, the compatibility level covers at least 95 % of
cases of an entire population. Since compatibility levels and harmonic emission limits have
been designed for European countries, this entire population refers to the POIs of all customers
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in Europe. In other words, the 95 percentile of all harmonic levels at POIs in Europe should
not exceed the level of compatibility established in IEC 61000-2-2. If the same harmonic current
flows in a network whose design is different from that of the European reference network, the
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95 percentile of the harmonic level could be either lower or higher than the compatibility level,
depending
...