EN IEC 61788-26:2020

Superconductivity - Part 26: Critical current measurement - DC critical current of RE-Ba-Cu-O composite superconductors

IEC 61788-26:2020 specifies a test method for determining the DC critical current of short RE (rare earth)-Ba-Cu-O (REBCO) composite superconductor specimens that have a shape of straight flat tape. This document applies to test specimens shorter than 300 mm and having a rectangular cross section with an area of 0,03 mm2 to 7,2 mm2, which corresponds to tapes with width ranging from 1,0 mm to 12,0 mm and thickness from 0,03 mm to 0,6 mm. This method is intended for use with superconductor specimens that have critical current less than 300 A and n-values larger than 5 under standard test conditions: the test specimen is immersed in liquid nitrogen bath at ambient pressure without external magnetic field during the testing. Deviations from this test method that are allowed for routine tests and other specific restrictions are given in this document.

Supraleitfähigkeit - Teil 26: Messung des kritischen Stroms - Kritischer DC-Strom von RE-Ba-Cu-O Komposit Supraleitern

Supraconductivité - Partie 26: Mesurage du courant critique - Courant critique continu des composites supraconducteurs de RE-Ba-Cu-O

L’IEC 61788-26:2020 spécifie une méthode d'essai pour la détermination du courant critique continu des échantillons de composites supraconducteurs RE (terre rare)-Ba-Cu-O (REBCO) courts en forme de ruban plat et rectiligne. Le présent document s'applique aux échantillons d’essai d'une longueur inférieure à 300 mm et d'une superficie de section rectangulaire de 0,03 mm2 à 7,2 mm2, ce qui correspond aux rubans d’une largeur de 1,0 mm à 12,0 mm et d’une épaisseur de 0,03 mm à 0,6 mm. Cette méthode est destinée à être utilisée avec des échantillons de supraconducteurs caractérisés par un courant critique inférieur à 300 A et des valeurs n supérieures à 5 dans les conditions d’essai normalisées: l’échantillon d’essai est immergé dans un bain d’azote liquide à pression ambiante sans champ magnétique externe pendant l’essai. Le présent document spécifie les écarts par rapport à cette méthode d’essai qui sont admis dans les essais individuels de série, ainsi que d'autres restrictions spécifiques.

Superprevodnost - 26. del: Meritve kritičnega toka - Enosmerni kritični tok pri superprevodnikih iz kompozita RE-Ba-Cu-O (IEC 61788-26:2020)

General Information

• Status: Published
• Publication Date: 06-Aug-2020
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• ICS: 19.080 - Electrical and electronic testing
• ICS: 29.050 - Superconductivity and conducting materials
• Technical Committee: CLC/SR 90 - Superconductivity
• Drafting Committee: IEC/TC 90 - IEC_TC_90
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 07-Aug-2020
• Completion Date: 07-Aug-2020
• Ref Project: SIST EN IEC 61788-26:2020 - Superconductivity - Part 26: Critical current measurement - DC critical current of RE-Ba-Cu-O composite superconductors (IEC 61788-26:2020)

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-2020
Superprevodnost - 26. del: Meritve kritičnega toka - Enosmerni kritični tok pri
superprevodnikih iz kompozita RE-Ba-Cu-O (IEC 61788-26:2020)
Superconductivity - Part 26: Critical current measurement - DC critical current of RE-Ba-
Cu-O composite superconductors (IEC 61788-26:2020)
Supraleitfähigkeit - Teil 26: Messung des kritischen Stroms - Kritischer DC-Strom von
RE-Ba-Cu-O-Kompositsupraleitern (IEC 61788-26:2020)
Supraconductivité - Partie 26: Mesurage du courant critique - Courant critique continu
des composites supraconducteurs de RE-Ba-Cu-O (IEC 61788-26:2020)
Ta slovenski standard je istoveten z: EN IEC 61788-26:2020
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61788-26

NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2020
ICS 17.220.20; 19.080; 29.050
English Version
Superconductivity - Part 26: Critical current measurement - DC
critical current of RE-Ba-Cu-O composite superconductors
(IEC 61788-26:2020)
Supraconductivité - Partie 26: Mesurage du courant critique Supraleitfähigkeit - Teil 26: Messung des kritischen Stroms
- Courant critique continu des composites - Kritischer DC-Strom von RE-Ba-Cu-O Komposit
supraconducteurs de RE-Ba-Cu-O Supraleitern
(IEC 61788-26:2020) (IEC 61788-26:2020)
This European Standard was approved by CENELEC on 2020-07-16. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, 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
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61788-26:2020 E

European foreword
The text of document 90/455/FDIS, future edition 1 of IEC 61788-26, 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) 2021-04-16
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2023-07-16
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 61788-26:2020 was approved by CENELEC as a European
Standard without any modification.

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 - International Electrotechnical Vocabulary - - -
Part 815: Superconductivity
IEC 61788-26 ®
Edition 1.0 2020-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Superconductivity –
Part 26: Critical current measurement – DC critical current of RE-Ba-Cu-O

composite superconductors
Supraconductivité –
Partie 26: Mesurage du courant critique – Courant critique continu des

composites supraconducteurs de RE-Ba-Cu-O

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.20; 19.080; 29.050 ISBN 978-2-8322-8436-0

– 2 – IEC 61788-26:2020 © IEC 2020
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 Critical current measuring system . 8
6 Specimen preparation and setup . 8
6.1 Length . 8
6.2 Mounting of the specimen . 9
7 Critical current measurement . 9
8 Calculation of results . 9
8.1 Critical current criteria. 9
8.2 n-value (optional) . 11
9 Uncertainty of measurement . 11
10 Test report . 11
10.1 Identification of test specimen . 11
10.2 Reporting of I values . 11
c
10.3 Reporting of I test conditions . 11
c
Annex A (informative)  Additional information relating to measurement, apparatus, and
calculation . 12
A.1 General information . 12
A.2 Measurement condition . 12
A.3 Apparatus . 13
A.3.1 Measurement holder material . 13
A.3.2 Measurement holder construction . 13
A.4 Specimen preparation . 14
A.5 Measurement procedure . 14
A.5.1 Voltage leads . 14
A.5.2 Cooling process . 14
A.5.3 Temperature of liquid nitrogen bath . 14
A.5.4 System noise and other contributions to the measured voltage . 15
A.6 Calculation of n-value . 16
Annex B (informative) Evaluation of combined standard uncertainty for REBCO
I measurement [8] . 17
c
B.1 Practical critical current measurement . 17
B.2 Model equation . 18
B.3 I measurement results . 19
c
B.4 Combined standard uncertainty [11] . 21
B.5 Type B uncertainty evaluation . 22
B.5.1 General . 22
B.5.2 Uncertainty of L measurement . 22
B.5.3 Uncertainty of voltage measurement . 22

IEC 61788-26:2020 © IEC 2020 – 3 –
B.5.4 Uncertainty of current measurement . 23
B.5.5 Uncertainty of temperature measurement . 23
B.5.6 Uncertainty coming from intrinsic non-uniformity of I . 24
c
B.5.7 Comparison between types A and B combined standard uncertainties . 25
B.6 Influence of current ramp rate on the total uncertainty . 26
Bibliography . 27

Figure 1 – Schematic view of measurement setup . 9
Figure 2 – Intrinsic U-I characteristic . 10
Figure 3 – U-I curve with a current transfer component . 10
Figure A.1 – Illustration of a measurement configuration for a short specimen of a few
hundred amperes class REBCO conductor . 13
Figure A.2 – Temperature dependence of I for commercial REBCO superconductors
c
(data from [9]) . 14
Figure A.3 – Pressure dependence of boiling temperature of liquid nitrogen . 15
Figure B.1 – Typical circuit to measure I . 17
c
Figure B.2 – Typical voltage–current (U-I) characteristic of a superconductor . 18
Figure B.3 – Ramp time dependence of total RSU of I for conductors B, C, and D . 26
c
Table A.1 – Thermal contraction data of superconductor

and sample‑holder materials [1] . 13
Table B.1 – Conductors distributed in the international RRT . 19
Table B.2 – I data for conductor A . 19
c
Table B.3 – I data for conductor B . 20
c
Table B.4 – I data for conductor C . 20
c
Table B.5 – I data for conductor D . 20
c
Table B.6 – Statistics for each conductor . 2
...