IEC 61788-14:2010

IEC 61788-14 ®
Edition 1.0 2010-06
INTERNATIONAL
STANDARD
Superconductivity –
Part 14: Superconducting power devices – General requirements for
characteristic tests of current leads designed for powering superconducting
devices
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
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: 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.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC 61788-14 ®
Edition 1.0 2010-06
INTERNATIONAL
STANDARD
Superconductivity –
Part 14: Superconducting power devices – General requirements for
characteristic tests of current leads designed for powering superconducting
devices
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
U
ICS 29.050 ISBN 978-2-88912-006-2
– 2 – 61788-14 © IEC:2010(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.6
2 Normative references .6
3 Terms and definitions .6
4 Principles .7
5 Characteristic test items .8
6 Characteristic test methods .9
6.1 Structure inspection .9
6.2 Stress/strain effect test.10
6.3 Thermal property test .10
6.4 Rated current-carrying test .11
6.5 Contact resistance test.12
6.6 Voltage drop test .12
6.7 High voltage test .12
6.8 Pressure drop test.13
6.9 Leak tightness test .13
6.10 Safety margin test .14
7 Reporting .15
8 Precautions .15
Annex A (informative) Supplementary information relating to Clauses 1 to 8.16
Annex B (informative) Typical current leads.18
Annex C (informative) Explanation figures to facilitate understanding of test methods .22
Annex D (informative) Test items and methods for a HTS component .24
Bibliography.26

Figure B.1 – Schematic diagram of self-cooled normal conducting current leads.18
Figure B.2 – Schematic diagram of forced flow cooled normal conducting current leads .19
Figure B.3 – Schematic diagram of current leads composed of forced flow cooled normal
conducting section and HTS section in vacuum environment .19
Figure B.4 – Schematic diagram of current leads composed of forced flow cooled normal
conducting section and HTS section in GHe environment .20
Figure B.5 – Schematic diagram of current leads composed of LN /GN /GHe cooled
2 2
normal conducting section and self-sufficient evaporated helium cooled HTS section .20
Figure B.6 – Schematic diagram of current leads composed of conduction cooled normal
conducting section and HTS section .21
Figure C.1 – Schematic drawing of a temperature profile during the rated current-carrying
test .22
Figure C.2 – Schematic drawing of a pressure dependency of the breakdown voltage in
the Paschen tightness test.22
Figure C.3 – Schematic drawing of a time dependency of the voltage rise at the quench
test .23

Table 1 – Characteristic test items and test execution stages for current leads .9
Table D.1 – Characteristic test items for a HTS component .24

61788-14 © IEC:2010(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SUPERCONDUCTIVITY –
Part 14: Superconducting power devices –
General requirements for characteristic tests of current
leads designed for powering superconducting devices

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 61788-14 has been prepared by IEC technical committee 90:
Superconductivity.
The text of this standard is based on the following documents:
FDIS Report on voting
90/244/FDIS 90/250/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.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61788 series, published under the general title Superconductivity,
can be found on the IEC website.

– 4 – 61788-14 © IEC:2010(E)
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site 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.
A bilingual version of this standard may be issued at a later date.

61788-14 © IEC:2010(E) – 5 –
INTRODUCTION
Current leads are indispensable components of superconducting devices in practical uses such
as MRI diagnostic equipment, NMR spectrometers, single crystal growth devices, SMES,
particle accelerators such as Tevatron, HERA, RHIC and LHC, experimental test instruments for
nuclear fusion reactors, such as ToreSupra, TRIAM, LHD, EAST, KSTAR, W7-X, JT-60SA and
ITER, etc., and of advanced superconducting devices in the near future in practical uses such as
magnetic levitated trains, superconducting fault current limiters, superconducting transformers,
etc.
The major functions of current leads are to power high currents into superconducting devices
and to minimize the overall heat load, including heat leakage from room temperature to
cryogenic temperature and Joule heating through current leads. For this purpose, current leads
are dramatically effective for lowering the overall heat load to use the high temperature
superconducting component as a part of the current leads.
On the other hand, the current lead technologies applied to superconducting devices depend on
each application, as well as on the manufacturer's experience and accumulated know-how. Due
to their use as component parts, it is difficult to judge the compatibility, flexibility between
devices, convenience, overall economical efficiency, etc of current leads. This may impede
progress in the growth and development of superconducting equipment technology and its
application to commercial activities, which is a cause for concern.
Consequently, it is judged industrially effective to clarify the definition of current leads to be
applied to superconducting devices and to standardize the common characteristic test methods
in a series of general rules.
– 6 – 61788-14 © IEC:2010(E)
SUPERCONDUCTIVITY –
Part 14: Superconducting power devices –
General requirements for characteristic tests of current
leads designed for powering superconducting devices

1 Scope
This part of IEC 61788 provides general requirements for characteristic tests of conventional as
well as superconducting current leads to be used for
...