EN 61660-1:1997

Short-circuit currents in d.c. auxiliary installations in power plants and substations - Part 1: Calculation of short-circuit currents

Describes method for calculating short-circuit currents in d.c. auxilliary systems in power plants and substations, which can be equipped with the following equipment, acting as short-circuit current sources: - rectifiers in three-phase a.c. bridge connection for 50 Hz; - stationary lead-acid batteries; - smoothing capacitors; - d.c. motors with independent excitation Provides a generally applicable method of calculation which produces results of sufficient accuracy on the conservative side.

Kurzschlußströme in Gleichstrom-Eigenbedarfsanlagen in Kraftwerken und Schaltanlagen - Teil 1: Berechnung der Kurzschlußströme

Courants de court-circuit dans les installations auxiliaires alimentées en courant continu dans les centrales et les postes - Partie 1: Calcul des courants de court-circuit

Décrit une méthode de calcul des courants de court-circuit des réseaux auxiliaires en courant continu dans des centrales et des postes, qui peuvent être équipés des éléments suivants, agissant comme sources de courants de court-circuit: - redresseurs dans les ponts triphasés en courant alternatif pour 50 Hz; - batteries stationnaires au plomb; - condensateurs de lissage; - moteurs à courant continu avec excitation indépendante. Fournit une méthode générale de calcul donnant des résultats suffisamment précis et par excès.

Kratkostični toki v pomožnih enosmernih napeljavah elektrarn in transformatorskih postaj - 1. del: Računanje kratkostičnih tokov (IEC 61660-1:1997)

General Information

• Status: Published
• Publication Date: 23-Jul-1997
• Withdrawal Date: 31-Mar-1998
• ICS: 29.240.01 - Power transmission and distribution networks in general
• Technical Committee: CLC/SR 73 - Short-circuit currents
• Drafting Committee: IEC/TC 73 - IEC_TC_73
• Parallel Committee: IEC/TC 73 - IEC_TC_73
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 24-Jul-1997
• Completion Date: 24-Jul-1997
• Ref Project: SIST EN 61660-1:1998 - Short-circuit currents in d.c. auxiliary installations in power plants and substations - Part 1: Calculation of short-circuit currents

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-1998
.UDWNRVWLþQLWRNLYSRPRåQLKHQRVPHUQLKQDSHOMDYDKHOHNWUDUQLQ
WUDQVIRUPDWRUVNLKSRVWDMGHO5DþXQDQMHNUDWNRVWLþQLKWRNRY,(&

Short-circuit currents in d.c. auxiliary installations in power plants and substations - Part
1: Calculation of short-circuit currents
Kurzschlußströme in Gleichstrom-Eigenbedarfsanlagen in Kraftwerken und
Schaltanlagen - Teil 1: Berechnung der Kurzschlußströme
Courants de court-circuit dans les installations auxiliaires alimentées en courant continu
dans les centrales et les postes - Partie 1: Calcul des courants de court-circuit
Ta slovenski standard je istoveten z: EN 61660-1:1997
ICS:
17.220.01 Elektrika. Magnetizem. Electricity. Magnetism.
Splošni vidiki General aspects
29.240.01 2PUHåMD]DSUHQRVLQ Power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks in
QDVSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME
CEI
INTERNATIONALE
IEC
61660-1
INTERNATIONAL
Première édition
STANDARD
First edition
1997-06
Courants de court-circuit dans les installations
auxiliaires alimentées en courant continu
dans les centrales et les postes –
Partie 1:
Calcul des courants de court-circuit
Short-circuit currents in d.c. auxiliary installations
in power plants and substations –
Part 1:
Calculation of short-circuit currents
 IEC 1997 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun any form or by any means, electronic or mechanical,
procédé, électronique ou mécanique, y compris la photo- including photocopying and microfilm, without permission in
copie et les microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http: //www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
V
PRICE CODE
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

61660-1 © IEC:1997 – 3 –
CONTENTS
Page
FOREWORD . 5
Clause
1 General. 7
1.1 Scope and object . 7
1.2 Normative references. 7
1.3 Definitions. 9
1.4 Symbols and subscripts . 11
2 Calculation of short-circuit currents. 15
2.1 General. 15
2.2 Calculating methods. 21
2.3 Resistance and inductance of conductor . 25
2.4 Rectifier. 27
2.5 Battery. 37
2.6 Capacitor. 41
2.7 DC motor with independent excitation . 49
3 Calculation of the total short-circuit current . 59
3.1 Correction factor. 59
3.2 Superimposing the partial short-circuit currents at the short-circuit location . 61
3.3 Standard approximation function. 63
Annex A – Equations for the calculation of λ , κ , κ and t
D D C pC . 67

61660-1 © IEC:1997 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SHORT-CIRCUIT CURRENTS IN DC AUXILIARY INSTALLATIONS
IN POWER PLANTS AND SUBSTATIONS –
Part 1: Calculation of short-circuit currents
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization
comprising all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the
form of standards, technical reports or guides and they are accepted by the National Committees in that
sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the
subject of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard 61660-1 has been prepared by IEC technical committee 73: Short-circuit
currents.
The text of this standard is based on the following documents:
FDIS Report on voting
73/84/FDIS 73/97/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.
Annex A is for information only.
IEC 61660 consists of the following parts, under the general title: Short-circuit currents in d.c.
auxiliary installations in power plants and substations:
– Part 1: 1997, Calculation of short-circuit currents
– Part 2: 1997, Calculation of effects
– Part 3: 199X, Examples of calculations (in preparation).
The contents of the corrigenda of February 1999 and March 2000 have been included in this
copy.
61660-1 © IEC:1997 – 7 –
SHORT-CIRCUIT CURRENTS IN DC AUXILIARY INSTALLATIONS
IN POWER PLANTS AND SUBSTATIONS –
Part 1: Calculation of short-circuit currents
1 General
1.1 Scope and object
This part of IEC 61660 describes a method for calculating short-circuit currents in d.c. auxiliary
systems in power plants and substations. Such systems can be equipped with the following
equipment, acting as short-circuit current sources:
– rectifiers in three-phase a.c. bridge connection for 50 Hz;
– stationary lead-acid batteries;
– smoothing capacitors;
– d.c. motors with independent excitation.
NOTE – Rectifiers in three-phase a.c. bridge connection for 60 Hz are under consideration. The data of other
equipment may be given by the manufacturer.
This standard is only concerned with rectifiers in three-phase a.c. bridge connection. It is not
concerned with other types of rectifiers.
The purpose of the standard is to provide a generally applicable method of calculation which
produces results of sufficient accuracy on the conservative side. Special methods, adjusted to
particular circumstances, may be used if they give at least the same precision. Short-circuit
currents, resistances and inductances may also be ascertained from system tests or
measurements on model systems. In existing d.c. systems the necessary values can be
ascertained from measurements taken at the assumed short-circuit location. The load current
is not taken into consideration when calculating the short-circuit current. It is necessary to
distinguish between two different values of short-circuit current:
– the maximum short-circuit current which determines the rating of the electrical
equipment;
– the minimum short-circuit current which can be taken as the basis for fuse and protection
ratings and settings.
1.2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 61660. At the time of publication, the edition indicated
was valid. All normative documents are subject to revision, and parties to agreements based
on this part of IEC 61660 are encouraged to investigate the possibility of applying the most
recent editions of the normative documents indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60038: 1983, IEC standard voltages

61660-1 © IEC:1997 – 9 –
IEC 60050(151): 1978, International Electrotechnical Vocabulary (IEV) – Chapter 151:
Electrical and magnetic devices
IEC 60050(441): 1984, International Electrotechnical Vocabulary (IEV) – Chapter 441:
Switchgear, controlgear and fuses
IEC 60896-1: 1987, Stationary lead-acid batteries – General requirements and methods of test
– Part 1: Vented types
Amendment 1 (1988)
Amendment 2 (1990)
IEC 60909: 1988, Short-circuit current calculation in three-phase a.c. systems
IEC 61660-2: 1997, Short-circuit currents in d.c. auxiliary installations in power plants and
substations – Part 2: Calculation of effects
1.3 Définitions
For the purpose of this part of IEC 61660, the following definitions apply.
1.3.1 short circuit: The accidental or intentional connection, by a relatively low resistance
or impedance, of two or more points in a circuit which are normally at different voltages.
[IEV 151-03-41]
NOTE – In this standard the connection is assumed to have zero impedance.
1.3.2 short-circuit current: An over-current resulting from a short circuit due to a fault or an
incorrect connection in an electric circuit. [IEV 441-11-07]
NOTE – It is necessary to distinguish between the short-circuit current at the short-circuit location and in the
network branches.
1.3.3 partial short-circuit current: The short-circuit current at the short-circuit location
being fed from one source with all other sources disconnected.
1.3.4 common branch: A network branch with several partial short-circuit currents from
different sources.
1.3.5 initial symmetrical short-circuit current I ′′ : The r.m.s. value of the a.c. symmetrical
k
component of a prospective short-circuit current applicable at the instant of short circuit if the
impedance remains at zero time value.
1.3.6 peak short-circuit current i : The maximum possible instantaneous value of the
p
prospective short-circuit current at the d.c. side (figures 1 and 2).
1.3.7 quasi steady-state short-circuit current I : The value of the short-circuit current at
k
the d.c. side 1 s after the beginning of the short circuit.
1.3.8 time to peak t : The interval between the initiation of the short circuit and the peak
p
value of the short-circuit current (figures 1 and 2).
1.3.9 short-circuit duration T : The time interval between the initiation of the short circuit
k
and the breaking of the d.c. short-circuit current.
1.3.10 nominal system voltage U : Voltage (line-to-line) by which a three-phase a.c.
n
system is designated and to which certain operating characteristics are referred. Values are
given in IEC 60038.
61660-1 © IEC:1997 – 11 –
1.3.11 nominal voltage U of a lead-acid battery: The nominal voltage of a lead-acid
nB
battery is given by the manufacturer. If the value is unknown, then the nominal voltage of one
cell 2,0 V multiplied by the number of cells in series may be used.
1.3.12 stationary battery: A battery designed for service in a fixed location and which is
permanently connected to the load and to the associated battery charging circuit (see
IEC 60896-1).
1.3.13 final voltage of a battery (end-of-discharge voltage): The minimum permissible
voltage after a specified discharge time.
1.4 Symbols and subscripts
All equations are written without specifying units. The symbols represent quantities possessing
both numerical values and dimensions that are independent of units, provided a coherent unit
system is chosen, for example the International System of Units (SI).
1.4.1 Symbols
A Conductor cross-section
a Centre-line distance between conductors
d Thickness of rectangular conductor
C Capacitance
c Voltage factor according to IEC 60909
cU / 3 Equivalent voltage source according to IEC 60909
n
E Open-circuit voltage of a battery
B
f System frequency
b Height of rectangular conductor
′′
I Three-phase initial symmetrical short-circuit current
k
I Quasi steady-state short-circuit current
k
I Rated current
r
i Instantaneous value of current
i ,i Sections of the standard approximation function
1 2
i Short-circu
...