The Basic Insulation Characteristics of Solid-Nitrogen for Cryocooling of HTS Systems

고온초전도 시스템 냉각용 고화질소의 기초 절연 특성

  • 최재형 (경상대학교 전기공학과 및 공학연구원) ;
  • 최진욱 (경상대학교 전기공학과 및 공학연구원) ;
  • 이해근 (고려대학교 신소재공학부) ;
  • 송정빈 (고려대학교 신소재공학부) ;
  • 김해종 (한국전기연구원 초전도연구센터) ;
  • 성기철 (한국전기연구원 초전도연구센터) ;
  • 김상현 (경상대학교 전기공학과 및 공학연구원)
  • Published : 2009.01.01


Recently, for improvement of the magnetic field of high temperature superconductor (HTS) apparatus, many studies investigating on operating in the range of $20{\sim}65\;K$ with liquid helium or the conducting method using cryocooler are actively reviewed. Also, the cooling method using solid nitrogen as cryogen is being suggested. Since the nitrogen has very large specific heat in solid state, it is expected that it can be operated for a long time without a continuous supply of cooling energy. However, there are still insufficient data on the characteristics of solid nitrogen such as thermodynamic properties and liquid-solid phase change. Especially, there was almost no study done on the electrical insulation properties of solid nitrogen so far. In this study, solid nitrogen to find the electrical characteristics was made by using cryocooler and cryostat, and investigated the flashover discharge and breakdown. The results of this study will be useful as a basic data for electrical insulation design of the HTS system using solid nitrogen as cryogen.


  1. 이해근. '고온초전도 전자기 마그넷을 위한 새로운 개념의 냉각 시스템', 초전도와 저온공학, Vol. 2, No. 2, pp. 27-36, 2000
  2. S. S. Oh, 'Development of Solid-Nitrogen cooled HTS Magnets', Proceeding of KIASC Annual Meeting. pp. 19-22, 2000
  3. P. Hales, P. Hirst, S. Milward, S. Harrison, and H. jones, 'A Solid-Mitrogen Cooled High-Temperature Supercond-ucting Magnet for Use m Magnetohydrodynamic Marine Propulsion', IEEE Trans. Appl. Supercond., Vol. 16, No.2, pp. 1419-1422, 2006
  4. 변정주, 이윤숙, 장호명, '극저온 냉동을 위한 액체질소의 응고 실험 및 해석', 대한설비공학회 동계학술발표회 논문집, pp. 105-110, 2001
  5. S. M. Baek, J. M. Joung and S. H. Kim, 'Effects of Temperature and Pressure on the Breakdown Charac- teristics of Liquid Nitrogen', KIEE International Trans. on EA, Vol. 3, No.5, pp. 171-176, 2003
  6. B. J. Haid, H. Lee, Y. Iwasa, S. S. Oh, Y. K. Kwon and K. S. Ryu, 'A 'permanent' high-temperature supercon-ducting magnet operated in thermal communication with a mass of solid nitrogen', Cryogenics, Vol. 42, pp. 229-244, 2002
  7. J. Bascunan. H. Lee, E. S. Bobrov, S. Hahn, and Y. Iwasa, 'A 500 MHz/200 mm RT Bore Solid Neon Cooled $\text Nb_3Sn$ MRI Magnet- A Status Report', IEEE Trans. Appl. Supercond., Vol. 16, No.2, pp. 1535-1538, 2006
  8. IEC 60243-1, 'Electrical strength of insulation materials-Test methods-Part 1: Test at power frequencies', 1995
  9. W. Yao, J. Bascunan, W.S. Kim, S. Hahn, H. Lee, and Y. Iwasa, 'A Solid Nitrogen Cooled MgB2 'Demonstration' Coil for MHI Applications', IEEE Trans. Appl. Supercond., Vol. 18, No.2, pp. 912-915, 2008
  10. B. Haid, H. Lee, Y. Iwasa, S.S. Oh, H.S. Ha, Y.K. Kwon, K.S. Ryu 'Stand-Alone Solid Nitrogen Cooled 'Permanent' High-Temperature Superconducting Magnet System', IEEE Trans. Appl. Supercond., Vol. 11, No. 1, pp. 2244-2247, 2001