BS EN IEC 61788-26:2020
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Superconductivity – Critical current measurement. DC critical current of RE-Ba-Cu-O composite superconductors
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 34 |
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.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 5 | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications |
| 7 | English CONTENTS |
| 9 | FOREWORD |
| 11 | INTRODUCTION |
| 12 | 1 Scope 2 Normative references 3 Terms and definitions |
| 13 | 4 Principle 5 Apparatus 5.1 General 5.2 Critical current measuring system 6 Specimen preparation and setup 6.1 Length |
| 14 | 6.2 Mounting of the specimen 7 Critical current measurement 8 Calculation of results 8.1 Critical current criteria Figures Figure 1 – Schematic view of measurement setup |
| 15 | Figure 2 – Intrinsic U-I characteristic Figure 3 – U-I curve with a current transfer component |
| 16 | 8.2 n-value (optional) 9 Uncertainty of measurement 10 Test report 10.1 Identification of test specimen 10.2 Reporting of Ic values 10.3 Reporting of Ic test conditions |
| 17 | Annex A (informative)Additional information relating to measurement, apparatus, and calculation A.1 General information A.2 Measurement condition |
| 18 | A.3 Apparatus A.3.1 Measurement holder material A.3.2 Measurement holder construction Figure A.1 – Illustration of a measurement configuration fora short specimen of a few hundred amperes class REBCO conductor Tables Table A.1 – Thermal contraction data of superconductor and sample‑holder materials [1] |
| 19 | A.4 Specimen preparation A.5 Measurement procedure A.5.1 Voltage leads A.5.2 Cooling process A.5.3 Temperature of liquid nitrogen bath Figure A.2 – Temperature dependence of Ic forcommercial REBCO superconductors (data from [9]) |
| 20 | A.5.4 System noise and other contributions to the measured voltage Figure A.3 – Pressure dependence of boiling temperature of liquid nitrogen |
| 21 | A.6 Calculation of n-value |
| 22 | Annex B (informative)Evaluation of combined standard uncertainty for REBCO Ic measurement [8] B.1 Practical critical current measurement Figure B.1 – Typical circuit to measure Ic |
| 23 | B.2 Model equation Figure B.2 – Typical voltage–current (U-I) characteristic of a superconductor |
| 24 | B.3 Ic measurement results Table B.1 – Conductors distributed in the international RRT Table B.2 – Ic data for conductor A |
| 25 | Table B.3 – Ic data for conductor B Table B.4 – Ic data for conductor C Table B.5 – Ic data for conductor D |
| 26 | B.4 Combined standard uncertainty [11] Table B.6 – Statistics for each conductor Table B.7 – ANOVA results for each conductor |
| 27 | B.5 Type B uncertainty evaluation B.5.1 General B.5.2 Uncertainty of L1 measurement B.5.3 Uncertainty of voltage measurement |
| 28 | B.5.4 Uncertainty of current measurement B.5.5 Uncertainty of temperature measurement |
| 29 | B.5.6 Uncertainty coming from intrinsic non-uniformity of Ic Table B.8 – Atmospheric pressure from 1 January 2014 to 31 December 2014 Table B.9 – Intrinsic Ic non-uniformity evaluated by RTR-SHPM |
| 30 | B.5.7 Comparison between types A and B combined standard uncertainties Table B.10 – Budget table of SUs of Ic measurements for conductor C Table B.11 – Comparison of the relative standard uncertaintiesfor conductors B, C, and D |
| 31 | B.6 Influence of current ramp rate on the total uncertainty Figure B.3 – Ramp time dependence of total RSU of Ic for conductors B, C, and D |
| 32 | Bibliography |
