SIST EN 60909-0:2016

Short-circuit currents in three-phase a.c. systems - Part 0: Calculation of currents

IEC 60909-0:2016 is applicable to the calculation of short-circuit currents in low-voltage three-phase AC systems, and in high-voltage three-phase AC systems, operating at a nominal frequency of 50 Hz or 60 Hz. It establishes a general, practicable and concise procedure leading to results which are generally of acceptable accuracy and deals with the calculation of short-circuit currents in the case of balanced or unbalanced short circuits. This second edition cancels and replaces the first edition published in 2001. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- contribution of windpower station units to the short-circuit current;
- contribution of power station units with ful size converters to the short-circuit current;
- new document structure.

Kurzschlussströme in Drehstromnetzen - Teil 0: Berechnung der Ströme

Courants de court-circuit dans les réseaux triphasés à courant alternatif - Partie 0: Calcul des courants

L'IEC 60909-0:2016 est applicable au calcul des courants de court-circuit dans les réseaux triphasés basse tension à courant alternatif, et dans les réseaux triphasés haute tension à courant alternatif, fonctionnant à une fréquence nominale de 50 Hz ou de 60 Hz. Elle établit une procédure générale, réalisable et concise conduisant à des résultats qui sont en général d'une précision acceptable. Et traite du calcul des courants de court-circuit dans le cas de courts-circuits symétriques et dissymétriques. Cette deuxième édition annule et remplace la première édition parue en 2001. Cette édition constitue une révision technique. Elle inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- contribution des groupes de production éoliens au courant de court-circuit;
- contribution des groupes de production avec convertisseurs grande capacité au courant de court-circuit;
- nouvelle structure du document.

Kratkostični toki v izmeničnih trifaznih sistemih - 0. del: Računanje tokov

Standard IEC 60909-0:2016 se uporablja za izračun kratkostičnih tokov v nizkonapetostnih izmeničnih trifaznih sistemih in visokonapetostnih izmeničnih trifaznih sistemih, ki delujejo pri nominalni frekvenci 50 Hz ali 60 Hz. Uveljavlja splošen, izvedljiv in strnjen postopek z rezultati, ki so običajno sprejemljive natančnosti, ter obravnava izračun kratkostičnih tokov v primeru uravnovešenih in neuravnovešenih kratkih stikov. Druga izdaja razveljavlja in nadomešča prvo izdajo, objavljeno leta 2001. Ta izdaja je tehnično popravljena izdaja. Ta izdaja vključuje naslednje znatne tehnične spremembe glede na prejšnjo izdajo:
– prispevek enot vetrnih elektrarn h kratkostičnemu toku;
– prispevek enot elektrarn s pretvorniki polne velikosti h kratkostičnemu toku;
– nova struktura dokumentov.

General Information

• Status: Published
• Publication Date: 28-Aug-2016
• ICS: 17.220.01 - Electricity. Magnetism. General aspects
• ICS: 29.240.20 - Power transmission and distribution lines
• Technical Committee: NTF - Electricity energy supply systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 08-Jul-2016
• Due Date: 12-Sep-2016
• Completion Date: 29-Aug-2016
• Ref Project: EN 60909-0:2016 - Short-circuit currents in three-phase a.c. systems - Part 0: Calculation of currents

Relations

• Replaces: SIST EN 60909-0:2002 - Short-circuit currents in three-phase a.c. systems - Part 0: Calculation of currents
• Effective Date: 01-Sep-2016
• Replaces: SIST EN 60909-0:2002 - Short-circuit currents in three-phase a.c. systems - Part 0: Calculation of currents
• Effective Date: 07-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60909-0:2016
01-september-2016
1DGRPHãþD
SIST EN 60909-0:2002
.UDWNRVWLþQLWRNLYL]PHQLþQLKWULID]QLKVLVWHPLKGHO5DþXQDQMHWRNRY
Short-circuit currents in three-phase a.c. systems - Part 0: Calculation of currents
Kurzschlussströme in Drehstromnetzen - Teil 0: Berechnung der Ströme
Courants de court-circuit dans les réseaux triphasés à courant alternatif - Partie 0: Calcul
des courants
Ta slovenski standard je istoveten z: EN 60909-0:2016
ICS:
17.220.01 Elektrika. Magnetizem. Electricity. Magnetism.
Splošni vidiki General aspects
29.240.20 Daljnovodi Power transmission and
distribution lines
SIST EN 60909-0:2016 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60909-0:2016

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SIST EN 60909-0:2016


EUROPEAN STANDARD EN 60909-0

NORME EUROPÉENNE

EUROPÄISCHE NORM
June 2016
ICS 17.220.01; 29.240.20 Supersedes EN 60909-0:2001
English Version
Short-circuit currents in three-phase a.c. systems -
Part 0: Calculation of currents
(IEC 60909-0:2016)
Courants de court-circuit dans les réseaux triphasés à Kurzschlussströme in Drehstromnetzen -
courant alternatif - Teil 0: Berechnung der Ströme
Partie 0: Calcul des courants (IEC 60909-0:2016)
(IEC 60909-0:2016)
This European Standard was approved by CENELEC on 2016-03-03. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.


European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN 60909-0:2016 E

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SIST EN 60909-0:2016
EN 60909-0:2016
European foreword
The text of document 73/172/CDV, future edition 2 of IEC 60909-0, prepared by IEC/TC 73
"Shortcircuit currents" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC
as EN 60909-0:2016.

The following dates are fixed:
(dop) 2016-12-10
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2019-06-10
standards conflicting with the
document have to be withdrawn

This document supersedes EN 60909-0:2001.

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.

Endorsement notice
The text of the International Standard IEC 60909-0:2016 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:

IEC 60865-1 NOTE Harmonized as EN 60865-1.
IEC 62428 NOTE Harmonized as EN 62428.
2

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SIST EN 60909-0:2016
EN 60909-0:2016
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.

NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu

Publication Year Title EN/HD Year

IEC 60038 (mod) 2009 IEC standard voltages EN 60038 2011
IEC 60050-131 -  International Electrotechnical - -
Vocabulary (IEV) -
Part 131: Circuit theory
IEC/TR 60909-1 2002 Short-circuit currents in three-phase e.c. - -
systems -
Part 1: Factors for the calculation of short-
circuit currents according to IEC 60909-0
IEC/TR 60909-2 2008 Short-circuit currents in three-phase a.c. - -
systems -
Part 2: Data of electrical equipment for
short-circuit current calculations
IEC 60909-3 2009 Short-circuit currents in three-phase a.c EN 60909-3 2010
systems -
Part 3: Currents during two separate
simultaneous line-to-earth short-circuits
and partial short-circuit currents flowing
through earth
IEC/TR 60909-4 2000 Short-circuit currents in three-phase a.c. - -
systems -
Part 4: Examples for the calculation of
short-circuit currents

3

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SIST EN 60909-0:2016



IEC 60909-0

®


Edition 2.0 2016-01




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Short-circuit currents in three-phase a.c. systems –

Part 0: Calculation of currents




Courants de court-circuit dans les réseaux triphasés à courant alternatif –

Partie 0: Calcul des courants

















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 17.220.01; 29.240.20 ISBN 978-2-8322-3158-6



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN 60909-0:2016
– 2 – IEC 60909-0:2016 © IEC 2016
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references. 8
3 Terms and definitions . 8
4 Symbols, subscripts and superscripts . 13
4.1 General . 13
4.2 Symbols . 13
4.3 Subscripts . 15
4.4 Superscripts . 16
5 Characteristics of short-circuit currents: calculating method . 16
5.1 General . 16
5.2 Calculation assumptions . 19
5.3 Method of calculation . 20
5.3.1 Equivalent voltage source at the short-circuit location . 20
5.3.2 Symmetrical components . 22
6 Short-circuit impedances of electrical equipment . 23
6.1 General . 23
6.2 Network feeders . 23
6.3 Transformers . 25
6.3.1 Two-winding transformers . 25
6.3.2 Three-winding transformers . 25
6.3.3 Impedance correction factors for two- and three-winding network
transformers . 27
6.4 Overhead lines and cables . 28
6.5 Short-circuit current-limiting reactors . 29
6.6 Synchronous machines . 29
6.6.1 Synchronous generators . 29
6.6.2 Synchronous compensators and motors. 31
6.7 Power station units . 31
6.7.1 Power station units with on-load tap-changer . 31
6.7.2 Power station units without on-load tap-changer . 32
6.8 Wind power station units . 33
6.8.1 General . 33
6.8.2 Wind power station units with asynchronous generator . 33
6.8.3 Wind power station units with doubly fed asynchronous generator . 34
6.9 Power station units with full size converter . 35
6.10 Asynchronous motors . 35
6.11 Static converter fed drives . 36
6.12 Capacitors and non-rotating loads . 36
7 Calculation of initial short-circuit current . 36
7.1 General . 36
7.1.1 Overview . 36
7.1.2 Maximum and minimum short-circuit currents . 41
7.1.3 Contribution of asynchronous motors to the short-circuit current . 42
7.2 Three-phase initial short-circuit current . 43
7.2.1 General . 43

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SIST EN 60909-0:2016
IEC 60909-0:2016 © IEC 2016 – 3 –
7.2.2 Short-circuit currents inside a power station unit with on-load tap-
changer . 44
7.2.3 Short-circuit currents inside a power station unit without on-load tap-
changer . 46
7.3 Line-to-line short circuit . 47
7.4 Line-to-line short circuit with earth connection . 47
7.5 Line-to-earth short circuit . 49
8 Calculation of peak short-circuit current . 49
8.1 Three-phase short circuit . 49
8.1.1 Single-fed and multiple single-fed short circuits . 49
8.1.2 Multiple-fed short circuit . 51
8.2 Line-to-line short circuit . 52
8.3 Line-to-line short circuit with earth connection . 52
8.4 Line-to-earth short circuit . 52
9 Calculation of symmetrical breaking current . 53
9.1 Three-phase short circuit . 53
9.1.1 Symmetrical breaking current of synchronous machines. 53
9.1.2 Symmetrical breaking current of asynchronous machines . 54
9.1.3 Symmetrical breaking current of power station units with doubly fed
asynchronous generator . 55
9.1.4 Symmetrical breaking current of power station units with full size
converter . 55
9.1.5 Symmetrical breaking current of network feeder . 56
9.1.6 Symmetrical breaking current in case of multiple single-fed short-
circuits . 56
9.1.7 Symmetrical breaking current in case of multiple-fed short circuits . 56
9.2 Unbalanced short-circuits . 57
10 DC component of the short-circuit current . 57
11 Calculation of steady-state short-circuit current . 58
11.1 General . 58
11.2 Three-phase short circuit . 58
11.2.1 Steady-state short-circuit current of one synchronous generator or one
power station unit . 58
11.2.2 Steady-state short-circuit current of asynchronous motor or generator. 61
11.2.3 Steady-state short-circuit current of wind power station unit with doubly
fed asynchronous generator . 61
11.2.4 Steady-state short-circuit current of wind power station unit with full size
converter . 61
11.2.5 Steady-state short-circuit current of network feeder . 61
11.2.6 Steady-state short-circuit current in case of multiple single-fed short
circuits . 61
11.2.7 Steady-state short-circuit current in case of multiple-fed short circuits . 62
11.3 Unbalanced short circuits . 62
12 Short circuits at the low-voltage side of transformers, if one line conductor is
interrupted at the high-voltage side . 62
13 Terminal short circuit of asynchronous motors . 64
14 Joule integral and thermal equivalent short-circuit current. 65
Annex A (normative) Formulas for the calculation of the factors m and n . 68
Annex B (informative) Nodal admittance and nodal impedance matrices . 69
Bibliography . 73

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SIST EN 60909-0:2016
– 4 – IEC 60909-0:2016 © IEC 2016

Figure 1 – Short-circuit current of a far-from-generator short circuit with constant AC
component (schematic diagram) . 17
Figure 2 – Short-circuit current of a near-to-generator short-circuit with decaying AC
component (schematic diagram) . 18
Figure 3 – Characterization of short-circuits and their currents . 19
"
Figure 4 – Illustration for calculating the initial symmetrical short-circuit current  in
I
k
compliance with the procedure for the equivalent voltage source . 21
Figure 5 – System diagram and equivalent circuit diagram for network feeders . 24
Figure 6 – Three-winding transformer (example) . 27
Figure 7 – Diagram to determine the short-circuit type (Figure 3) for the highest initial
short-circuit current referred to the initial three-phase short-circuit current when the
impedance angles of the sequence impedances Z , Z , Z are identical . 38
(1) (2) (0)
Figure 8 – Examples of single-fed short-circuits . 40
Figure 9 – Example of a multiple single-fed short circuit . 40
Figure 10 – Example of multiple-fed short circuit . 41
Figure 11 – Short-circuit currents and partial short-circuit currents for three-phase
short circuits between generator and unit transformer with or without on-load tap-
changer, or at the connection to the auxiliary transformer of a power station unit and at
the auxiliary busbar A . 45
Figure 12 – Factor κ for series circuit as a function of ratio R/X or X/R . 50
Figure 13 – Factor µ for calculation of short-circuit breaking current I . 54
b
Figure 14 – Factor q for the calculation of the symmetrical short-circuit breaking
current of asynchronous motors . 55
Figure 15 – Factors λ and λ factors for cylindrical rotor generators . 60
min max
Figure 16 – Factors λ and λ for salient-pole generators . 60
min max
Figure 17 – Transformer secondary short-circuits, if one line (fuse) is opened on the
high-voltage side of a transformer Dyn5 . 63
Figure 18 – Factor m for the heat effect of the DC component of the short-circuit
current (for programming, the formula to calculate m is given in Annex A) . 66
Figure 19 – Factor n for the heat effect of the AC component of the short-circuit current
(for programming, the formula to calculate n is given in Annex A) . 67
Figure B.1 – Formulation of the nodal admittance matrix . 70
Figure B.2 – Example . 71

Table 1 – Voltage factor c . 22
Table 2 – Importance of short-circuit currents . 37
Table 3 – Factors α and β for the calculation of short-circuit currents with Formula
(96), rated transformation ratio t = U /U . 64
r rTHV rTLV
Table 4 – Calculation of short-circuit currents of asynchronous motors in the case of a
short circuit at the terminals . 65
Table B.1 – Impedances of electrical equipment referred to the 110 kV side . 71

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SIST EN 60909-0:2016
IEC 60909-0:2016 © IEC 2016 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

SHORT-CIRCUIT CURRENTS IN THREE-PHASE AC SYSTEMS –

Part 0: Calculation of currents

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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 60909-0 has been prepared by IEC technical committee 73: Short-
circuit currents.
This second edition cancels and replaces the first edition published in 2001. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) contribution of windpower station units to the short-circuit current;
b) contribution of power station units with ful size converters to the short-circuit current;
c) new document structure.

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SIST EN 60909-0:2016
– 6 – IEC 60909-0:2016 © IEC 2016
The text of this standard is based on the following documents:
CDV Report on voting
73/172/CDV 73/175A/RVC

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 in the IEC 60909 series, published under the general title Short-circuit
currents in three-phase a.c. systems, can be found on the IEC website.
This part of IEC 60909 is to be read in conjunction with the following International Standards
and Technical Reports:
– IEC TR 60909-1:2002, Short-circuit currents in three-phase a.c. systems – Part 1: Factors
for the calculation of short-circuit currents according to IEC 60909-0
– IEC TR 60909-2:2008, Short-circuit currents in three-phase a.c. systems – Part 2: Data of
electrical equipment for short-circuit current calculations
– IEC 60909-3:2009, Short-circuit currents in three-phase a.c. systems – Part 3: Currents
during two separate simultaneous line-to-earth short circuits and partial short-circuit
currents flowing through earth
– IEC TR 60909-4:2000, Short-circuit currents in three-phase a.c. systems – Part 4:
Examples for the calculation of short-circuit currents
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website 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.

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SIST EN 60909-0:2016
IEC 60909-0:2016 © IEC 2016 – 7 –
SHORT-CIRCUIT CURRENTS IN THREE-PHASE AC SYSTEMS –

Part 0: Calculation of currents



1 Scope
This part of IEC 60909 is applicable to the calculation of short-circuit currents
• in low-voltage three-phase AC systems, and
• in high-voltage three-phase AC systems,
operating at a nominal frequency of 50 Hz or 60 Hz.
Systems at highest voltages of 550 kV and above with long transmission lines need special
consideration.
This part of IEC 60909 establishes a general, practicable and concise procedure leading to
results which are generally of acceptable accuracy. For this calculation method, an equivalent
voltage source at the short-circuit location is introduced. This does not exclude the use of
special methods, for example the superposition method, adjusted to particular circumstances,
if they give at least the same precision. The superposition method gives the short-circuit
current related to the one load flow presupposed. This method, therefore, does not
necessarily lead to the maximum short-circuit current.
This part of IEC 60909 deals with the calculation of short-circuit currents in the case of
balanced or unbalanced short circuits.
A single line-to-earth fault is beyond the scope of this part of IEC 60909.
For currents during two separate simultaneous single-phase line-to-earth short circuits in an
isolated neutral system or a resonance earthed neutral system, see IEC 60909-3.
Short-circuit currents and short-circuit impedances may also be determined by system tests,
by measurement on a network analyser, or with a digital computer. In existing low-voltage
systems it is possible to determine the short-circuit impedance on the basis of measurements
at the location of the prospective short circuit considered.
The calculation of the short-circuit impedance is in general based on the rated data of the
ele
...