Electrical behavior of Bi-2223/Ag tapes under applied alternating over-currents

• Published in: IEEE transactions on applied superconductivity Vol. 15; no. 2; pp. 2482 - 2487
• Main Authors: Seong-Woo Yim, Sung-Hun Lim, Hye-Rim Kim, Si-Dole Hwang, Kishio, K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Alternating over-current; Applied sciences; Bi-2223/Ag tapes; Conducting materials; Critical current; Current distribution; Current measurement; Electric power generation; Electrical engineering. Electrical power engineering; Electrical resistance measurement; ELECTRICITY; Electronics; Equivalence; Exact sciences and technology; High temperature superconductors; Materials; MATHEMATICAL ANALYSIS; Optimization; Protection; protection of HTS machine; quench development; QUENCHING MECHANISMS; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silver; Superconducting cables; Superconducting devices; Superconducting films; Superconducting materials; Superconducting tapes; SUPERCONDUCTIVITY; SUPERCONDUCTORS; TAPE; protection of HTS machine; Voltage current curve; quench development; Critical region; Bi-2223/Ag tapes; Experimental study; Thermal stability; Alternating over-current; Operating conditions; Critical current; Superconducting tapes; Current distribution; Optimal conditions; High temperature superconductor; Electrical characteristic; Alternating current
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2005.847493

As a study for the protection of HTS power machines operated under AC conditions, the electrical behavior of Bi-2223/Ag tapes with applied alternating over-currents was investigated. Using the HTS tape of 57 A I/sub c/ and 106 K T/sub c/, we measured the V-I curves for the over-critical current region from 150 A/sub p/ to 507 A/sub p/. From the experimental results, 3 matters were investigated. Firstly, using the resistance increase data obtained from the curves, quench development was analyzed as a function of the amplitude and duration of the applied currents. Secondly, to understand these phenomena in detail, we investigated the current distribution between the superconductor and the metal sheath in Bi-2223/Ag tape, applying the equivalent equations and data of V-I curves. Finally, we confirmed the relationship between the resistance and temperature generated by the over-critical current experimentally. As a result, we could find the optimal operating condition considering the protection of the HTS tape against the alternating over-current.