Title :
Development of a HTS Magnet System for Long-Run Operation Test in Sub-Cooled Nitrogen
Author :
Kim, Tae Jung ; Kang, Hyoungku ; Ahn, Min Cheol ; Lee, Chanjoo ; Bae, Duck Kweon ; Seok, Bok-Yeol ; Chang, Ho-Myung ; Ko, Tae Kuk
Author_Institution :
Dept. of Human Resources Dev., Korea Found. of Polytech. Colleges, Seoul
fDate :
6/1/2006 12:00:00 AM
Abstract :
This paper deals with the development of a 6.6 kV/200A HTS magnet for inductive superconducting fault current limiter (SFCL) that uses a sub-cooled nitrogen cooling system which is expected to be very useful to the applied HTS machines. The several characteristics of the HTS magnet such as critical current, electrical insulation and heat transfer can be enhanced in the sub-cooled nitrogen cooling system rather than in saturated liquid nitrogen (LN2) cooling system. To obtain sub-cooled nitrogen, LN2 was cooled down to 64 K with GM-cryocooler and its pressure was kept at 101 kPa with gaseous helium. In this investigation, the HTS magnet for a 6.6 kV/200 A SFCL was developed and its long-run operation characteristics were measured and analyzed. The characteristics of the sub-cooled nitrogen system like temperature, level of LN2 and pressure of cryogenic system were not degraded in spite of the several over current tests, electrical insulation tests, and even long-run operation tests with rated transport current
Keywords :
critical current density (superconductivity); cryogenics; fault current limiters; high-temperature superconductors; superconducting magnets; 101 kPa; 200 A; 6.6 kV; AC dielectric test; GM-cryocooler; HTS machines; HTS magnet system; HTS transformer; critical current; cryogenic system; electrical insulation tests; gaseous helium; heat transfer; impulse test; inductive superconducting fault current limiter; long-run operation test; saturated liquid nitrogen cooling system; sub-cooled nitrogen cooling system; Cooling; Critical current; Dielectrics and electrical insulation; Fault current limiters; High temperature superconductors; Insulation testing; Nitrogen; Saturation magnetization; Superconducting magnets; System testing; Cryogenic system; HTS magnet; SFCL; sub-cooled nitrogen;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2006.871212
