Short-circuit currents - Calculation of effects - Part 2: Examples of calculation

IEC TR 60865-2:2015(E) shows the application of procedures for the calculation of mechanical and thermal effects due to short circuits as presented in IEC 60865-1. Thus, this technical report is an addition to IEC 60865-1. It does not, however, change the basis for standardized procedures given in that publication. This second edition cancels and replaces the first edition published in 1994 and constitutes a technical revision. It includes the following changes. The determinations for auto reclosure together with rigid conductors have been revised. The configurations in cases of flexible conductor arrangements have been changed. The influence of mid-span droppers to the span has been included. For vertical cable-connection the displacement and the tensile force onto the lower fixing point may be calculated now. Additional recommendations for foundation loads due to tensile forces have been added. The subclause for determination of the thermal equivalent short-circuits current has been deleted (is part of IEC 60909-0:2001 now). The standard IEC 60865-1:2011 has been reorganized and some of the symbols have been changed to follow the conceptual characteristic of international standards.

General Information

Status
Published
Publication Date
21-Apr-2015
Technical Committee
Current Stage
PPUB - Publication issued
Start Date
15-Apr-2015
Completion Date
22-Apr-2015
Ref Project

Buy Standard

Technical report
IEC TR 60865-2:2015 - Short-circuit currents - Calculation of effects - Part 2: Examples of calculation
English language
83 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (Sample)


IEC TR 60865-2 ®
Edition 2.0 2015-04
TECHNICAL
REPORT
Short-circuit currents – Calculation of effects –
Part 2: Examples of calculation
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 15
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 60 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,

77, 86 and CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
IEC TR 60865-2 ®
Edition 2.0 2015-04
TECHNICAL
REPORT
Short-circuit currents – Calculation of effects –

Part 2: Examples of calculation

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.220.01; 29.240.20 ISBN 978-2-8322-2551-6

– 2 – IEC TR 60865-2:2015 © IEC 2015
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Symbols and units . 7
4 Example 1 – Mechanical effects on a 10 kV arrangement with single rigid
conductors . 8
4.1 General . 8
4.2 Data . 9
4.3 Normal load case: Conductor stress and forces on the supports caused by
dead load . 9
4.4 Exceptional load case: Effects of short-circuit currents . 10
4.4.1 Maximum force on the central main conductor . 10
4.4.2 Conductor stress and forces on the supports . 11
4.5 Conclusions . 13
5 Example 2 – Mechanical effects on a 10 kV arrangement with multiple rigid
conductors . 14
5.1 General . 14
5.2 Data (additional to the data of Example 1) . 14
5.3 Normal load case: Conductor stress and forces on the supports caused by
dead load . 15
5.4 Exceptional load case: Effects of short-circuit currents . 15
5.4.1 Maximum forces on the conductors . 15
5.4.2 Conductor stress and forces on the supports . 16
5.5 Conclusions . 20
6 Example 3. – Mechanical effects on a high-voltage arrangement with rigid
conductors . 20
6.1 General . 20
6.2 Data . 21
6.3 Normal load case: Conductor stress and forces on the supports caused by

dead load . 22
6.4 Exceptional load case: Effects of short-circuit currents . 23
6.4.1 Maximum force on the central main conductor . 23
6.4.2 Conductor stress and forces on the supports . 23
6.4.3 Conclusions . 29
7 Example 4. – Mechanical effects on a 110 kV arrangement with slack conductors . 30
7.1 General . 30
7.2 Data . 31
7.3 Electromagnetic load and characteristic parameters . 32
7.4 Tensile force F during short-circuit caused by swing out . 34
t,d
7.5 Dynamic conductor sag at midspan . 35
7.6 Tensile force F after short-circuit caused by drop . 36
f,d
7.7 Horizontal span displacement b and minimum air clearance a . 36
h min
7.8 Conclusions . 36
8 Example 5. – Mechanical effects on strained conductors . 37
8.1 General . 37
8.2 Common data . 37
8.3 Centre-line distance between sub-conductors a = 0,1 m . 38
s
8.3.1 Electromagnetic load and characteristic parameters . 38
8.3.2 Tensile force F during short-circuit caused by swing out . 41
t,d
8.3.3 Dynamic conductor sag at midspan . 41
8.3.4 Tensile force F after short-circuit caused by drop . 42
f,d
8.3.5 Horizontal span displacement b and minimum air clearance a . 43
h min
8.3.6 Pinch force F . 43
pi,d
8.3.7 Conclusions . 43
8.4 Centre-line distance between sub-conductors a = 0,4 m . 44
s
8.4.1 Preliminary remarks . 44
8.4.2 Characteristic dimensions and parameters . 44
8.4.3 Pinch force F . 45
pi,d
8.4.4 Conclusions . 47
9 Example 6 – Mechanical effects on strained conductors with dropper in the middle
of the span . 47
9.1 General . 47
9.2 Common data . 48
9.3 Plane of the dropper parallel to the main conductors . 48
9.3.1 General . 48
9.3.2 Current flow along the whole length of the main conductor span . 49
9.3.3 Current flow along half of the length of the main conductor and along the
dropper . 57
9.4 Plane of the dropper perpendicular to the main conductors . 64
9.4.1 General . 64
9.4.2 Current flow along the whole length of the main conductor span . 64
9.4.3 Current flow along half of the length of the main conductor and along the
dropper . 69
10 Example 7 – Mechanical effects on vertical main conductors (droppers) . 77
10.1 General . 77
10.2 Data . 77
10.3 Short-circuit tensile force and maximum horizontal displacement . 78
10.4 Pinch force . 78
10.4.1 Static tensile force regarding droppers . 78
10.4.2 Characteristic dimensions and parameters . 79
10.4.3 Pinch force F . 80
pi,d
10.5 Conclusions . 81
11 Example 8 – Thermal effect on bare conductors . 81
11.1 General . 81
11.2 Data . 81
11.3 Calculations . 82
11.4 Conclusion . 82
Bibliography . 83

Figure 1 – Conductor arrangement . 8
Figure 2 – Position of the sub-conductors and connecting pieces . 14
Figure 3 – Two-span arrangement with tubular conductors. 21
Figure 4 – Arrangement with slack conductors . 31
Figure 5 – Arrangement with strained conductors . 37
Figure 6 – Arrangement with strained conductors and droppers in midspan. Plane of the

droppers parallel to the main conductors . 47

– 4 – IEC TR 60865-2:2015 © IEC 2015
Figure 7 – Possible arrangement of perpendicular droppers in three-phase system and
two-line system . 64
Figure 8 – Arrangement with strained conductors
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.