Overview
IEC 61788-26:2020 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies a precise test method for measuring the DC critical current of RE-Ba-Cu-O (REBCO) composite superconductors. This standard focuses on short, straight flat tape specimens of REBCO composites, which are widely used in superconductivity applications. The defined test applies to specimens less than 300 mm in length and with rectangular cross sections ranging from 0.03 mm² to 7.2 mm², corresponding to tape widths between 1.0 mm and 12.0 mm and thicknesses ranging from 0.03 mm to 0.6 mm.
The measurement is performed under controlled conditions where the specimen is immersed in a liquid nitrogen bath at ambient pressure and tested without an external magnetic field. The method is relevant for specimens with critical currents below 300 A and n-values greater than 5, ensuring reliable and reproducible critical current measurements.
Key Topics
- Test Scope: DC critical current assessment for short REBCO composite superconducting tapes, emphasizing standardized specimen dimensions for consistency.
- Measurement Conditions: Immersion in liquid nitrogen bath at ambient pressure without external magnetic field to simulate standard operating environments.
- Specimen Requirements: Flat, rectangular cross-section tapes with precise dimension specifications for width and thickness to suit high-accuracy tests.
- Critical Current (Ic) Criteria: Defined voltage-current characteristics and evaluation criteria for critical current calculation to maintain test repeatability.
- Apparatus and Setup: Detailed guidelines on measurement system configuration, including specimen mounting methods and electrical interface.
- Uncertainty Evaluation: Comprehensive approach to calculate and quantify measurement uncertainties, enhancing reliability.
- Reporting Requirements: Standardized test reporting elements that cover specimen identification, measurement results, and conditions.
Applications
IEC 61788-26:2020 is essential for manufacturers, researchers, and testing laboratories involved in superconductivity, especially where high-temperature REBCO tapes are used, including:
- Superconductor Wire and Tape Production: Ensures quality control and consistent characterization of superconducting tapes before deployment.
- Magnetic Resonance Imaging (MRI): Verification of critical current in superconducting components pertinent to medical imaging devices.
- Energy Storage Systems: Assessment of current-carrying capabilities of superconductors in large-scale superconducting magnetic energy storage (SMES) systems.
- Particle Accelerators and Magnets: Critical current measurements guide the development of superconducting magnets and cables for scientific instrumentation.
- Cryogenic Research Facilities: Supports standardized testing protocols for superconductor samples under cryogenic conditions.
Related Standards
For comprehensive understanding and complementary procedures, the following IEC and international standards align well with IEC 61788-26:2020:
- IEC 61788 Series: Entire series on superconductivity providing broader test methods and terminology, including AC and other composite superconductor measurements.
- IEC 60317: Standardization of test methods for electrical properties of superconducting materials.
- ISO/IEC Directives, Part 2: Guidelines on drafting and maintaining international standards, relevant to how IEC 61788-26 was developed.
- ASTM Standards on Superconductors: Alternative recognized test methodologies for superconductors, for cross-reference in material characterization.
Keywords: IEC 61788-26:2020, critical current measurement, RE-Ba-Cu-O superconductors, REBCO tapes, DC critical current, superconductivity standards, liquid nitrogen testing, superconductor specimen, cryogenic test method, superconducting tape characterization.
Open preview (PDF)Superconductivity - Part 26: Critical current measurement - DC critical current of RE-Ba-Cu-O composite superconductors
