EN IEC 61788-24:2018

SLOVENSKI STANDARD
01-november-2018
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Superconductivity - Part 24: Critical current measurement - Retained critical current after
double bending at room temperature of Ag-sheathed Bi-2223 superconducting wires
(IEC 61788-24:2018)
Supraleitfähigkeit - Teil 24: Messung des kritischen Stroms - Verbleibender kritischer
Strom nach Doppelbiegung bei Raumtemperatur in Ag-ummantelten Bi-2223
supraleitenden Drähten
Supraconductivité - Partie 24: Mesurage du courant critique - Courant critique retenu
après double flexion à température ambiante des fils supraconducteurs Bi-2223 avec
gaine Ag
Ta slovenski standard je istoveten z: EN IEC 61788-24:2018
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
29.060.10 Žice Wires
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61788-24

NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2018
ICS 29.050; 77.040.10; 17.220
English Version
Superconductivity - Part 24: Critical current measurement -
Retained critical current after double bending at room
temperature of Ag-sheathed Bi-2223 superconducting wires
(IEC 61788-24:2018)
Supraconductivité - Partie 24: Mesurage du courant critique Supraleitfähigkeit - Teil 24: Messung des kritischen Stroms
- Courant critique retenu après double flexion à température - Verbleibender kritischer Strom nach Doppelbiegung bei
ambiante des fils supraconducteurs Bi-2223 avec gaine Ag Raumtemperatur in Ag-ummantelten Bi-2223
(IEC 61788-24:2018) supraleitenden Drähten
(IEC 61788-24:2018)
This European Standard was approved by CENELEC on 2018-07-23. 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, Serbia, 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: Rue de la Science 23, B-1040 Brussels
© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61788-24:2018 E

European foreword
The text of document 90/402/FDIS, future edition 1 of IEC 61788-24, prepared by IEC/TC 90
"Superconductivity" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2019-04-23
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2021-07-23
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice
The text of the International Standard IEC 61788-24:2018 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 61788-3 NOTE Harmonized as EN 61788-3

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where 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 60050-815 2015 International Electrotechnical Vocabulary - - -
Part 815: Superconductivity
IEC 61788-24 ®
Edition 1.0 2018-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Superconductivity –
Part 24: Critical current measurement – Retained critical current after double

bending at room temperature of Ag-sheathed Bi-2223 superconducting wires

Supraconductivité –
Partie 24: Mesurage du courant critique – Courant critique retenu après double

flexion à température ambiante des fils supraconducteurs Bi-2223 avec gaine Ag

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220; 29.050; 77.040.10 ISBN 978-2-8322-5801-9

– 2 – IEC 61788-24:2018 © IEC 2018
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Principle . 8
5 Apparatus . 8
5.1 General . 8
5.2 Bending mandrel . 8
5.3 Critical current measurement holder . 8
5.4 Critical current measuring system . 9
6 Specimen preparation and set up . 9
6.1 Length of specimen . 9
6.2 Mounting of the specimen . 10
7 Measurement procedures . 10
7.1 Critical current measurement . 10
7.2 Double bending . 10
7.3 Retained critical current after bending . 11
8 Calculation of results . 11
8.1 Critical current criteria. 11
8.2 n-value (optional) . 11
9 Test report . 11
9.1 Identification of test specimen . 11
9.2 Report of I values and/or retained I ratio . 12
c c
9.3 Report of I test conditions . 12
c
Annex A (informative) Additional information relating to Clauses 1 to 9 . 13
A.1 General . 13
A.2 Measurement condition . 13
A.3 Apparatus measurement holder material . 13
A.4 Specimen preparation . 16
A.5 Measurement procedures . 16
A.5.1 Critical current measurement . 16
A.5.2 Bending . 18
A.6 Calculation of results . 19
A.6.1 Critical current criteria . 19
A.6.2 n-value . 19
A.7 Relative standard uncertainty . 20
Annex B (informative) Evaluation of combined standard uncertainty for the retained I
c
after double bending . 22
B.1 Practice of critical current measurement . 22
B.2 Model equation . 22
B.3 Operation for the retained I measurement . 23
c
B.4 Combined standard uncertainty . 23

IEC 61788-24:2018 © IEC 2018 – 3 –
B.5 Evaluation of standard uncertainty (SU) for each measurand . 24
B.5.1 Voltage tap length (L) . 24
B.5.2 Voltage (U) . 24
B.5.3 Current (I) . 25
B.6 Evaluation of combined standard uncertainty . 26
Bibliography . 29

Figure 1 – Sample holder . 9
Figure 2 – Intrinsic U-I characteristic . 12
Figure 3 – U-I characteristic with a current transfer component . 12
Figure A.1 – Measurement configuration for a few hundred ampere class conductor . 15
Figure A.2 – Clips . 15
Figure A.3 – Additional strain caused by voltage tap wires and solders . 16
Figure A.4 – Boiling temperature of liquid nitrogen versus atmospheric pressure . 17
Figure A.5 – Critical current versus temperature for a typical Bi-2223 wire . 18
Figure A.6 – Bending process . 19
Figure B.1 – U-I diagram . 22
Figure B.2 – Bending diameter dependence of the retained I and , where the
c COV
calculated curve of I /I gives Equation (B.24). 28
c c0
Table A.1 – Thermal expansion data of Bi-2223 superconductors and selected
materials . 14
Table A.2 – Average of the degree of retained criti
...