Progress in Superconductivity and Cryogenics (한국초전도ㆍ저온공학회논문지)

The Korean Society of Superconductivity and Cryogenics (한국초전도저온학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical analysis on the critical current evaluation and the correction of no-insulation HTS coil

  • Bonghyun Cho (Department of Electrical Engineering, Pusan National University) ;
  • Jiho Lee (Robotics Institute of Non-Destructive Inspection, Pusan National University)
  • Received : 2023.03.02
  • Accepted : 2023.03.30
  • Published : 2023.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

The International Electrotechnical Commission (IEC) 61788-26:2020 provides guidelines for measuring the critical current of Rare-earth barium copper oxide (REBCO) tapes using two methods: linear ramp and step-hold methods. The critical current measurement criterion, 1 or 0.1 μV/cm of electric field from IEC 61788-26 has been normally applied to REBCO coils or magnets. No-insulation (NI) winding technique has many advantages in aspects of electrical and thermal stability and mechanical integrity. However, the leak current from the NI REBCO coil can cause distortion in critical current measurement due to the characteristic resistance which causes the radial current flow paths. In this paper, we simulated the NI REBCO coil by applying both linear ramp and step-hold methods based on a simplified equivalent circuit model. Using the circuit analysis, we analyzed and evaluated both methods. By using the equivalent circuit model, we can evaluate the critical current of the NI REBCO coil, resulting in an estimation error within 0.1%. We also evaluate the accuracy of critical current measurement using both the linear ramp and step-hold methods. The accuracy of the linear ramp method is influenced by the inductive voltage, whereas the accuracy of the step-hold method depends on the duration of the hold-time. An adequate hold time, typically 5 to 10 times the time constant (τ), makes the step-hold method more accurate than the linear ramp method.

Keywords

Acknowledgement

This work was supported by a 2-Year Research Grant of Pusan National University.

References

  1. Seungyong Hahn, Dong Keun Park, Juan Bascunan, and Yukikazu Iwasa, "HTS Pancake Coils Without Turn-to-turn Insulation," IEEE Trans. Appl. Supercond., Vol. 21, No.3, June 2011, pp.1592-1595  https://doi.org/10.1109/TASC.2010.2093492
  2. Jung-Bin Song, and Seungyong Hahn, ""Leak Current" correction for critical current measurement of no-insulation HTS coil," Progress in Superconductivity and Cryogenics Vol.19, No.2, (2017), pp.48-52  https://doi.org/10.9714/PSAC.2017.19.2.048
  3. IEC 61788-26:2020 "Superconductivity - Part 26: Critical current measurement - DC critical current of RE-Ba-Cu-O composite superconductors," 2020 
  4. Xudong Wang, Seungyong Hahn, Youngjae Kim, Juan Bascunan, John Voccio, Haigun Lee, and Yukikazu Iwasa, "Turn-to-turn contact characteristics for an equivalent circuit model of no-insulation ReBCO pancake coil," Supercond. Sci. Technol. 26 (2013) 035012 (6pp) 
  5. Yukikazu Iwasa, Juan Bascunan, Seungyong Hahn, John Voccio, Youngjae Kim, Thibault Lecrevisse, Jungbin Song, and Kazuhiro Kajikawa "A High-Resolution 1.3-GHz/54-mm LTS/HTS NMR Magnet, " IEEE Trans. Appl. Supercond., Vol. 25, No. 3, June 2015, Art. No. 4301205 
  6. Dongkeun Park, Juan Bascunan, Philip C. Michael, Jiho Lee, Seungyong Hahn, and Yukikazu Iwasa, "Construction and Test Results of Coils 2 and 3 of a 3-Nested-Coil 800-MHz REBCO Insert for the MIT 1.3-GHz LTS/HTS NMR Magnet," IEEE Trans. Appl. Supercond., Vol. 28, No. 3, April 2018, Art. No. 4300205 
  7. Tao Wang, So Noguchi, Xudong Wang, Issei Arakawa, Katsuhiko Minami, Katsutoshi Monma, Atsushi Ishiyama, Seungyong Hahn, and Yukikazu Iwasa, "Analyses of Transient Behaviors of No- Insulation REBCO Pancake Coils During Sudden Discharging and Overcurrent," IEEE Trans. Appl. Supercond., Vol. 25, No. 3, June 2015, Art. No. 4603409 
  8. Yukikazu Iwasa. Case Studies in Superconducting Magent, 2nd Edition. Springer, New York, 2009.