AC transport losses calculation in a Bi-2223 current lead using thermal coupling with an analytical formula

• Published in: IEEE transactions on applied superconductivity Vol. 15; no. 2; pp. 1508 - 1511
• Main Authors: Berger, K., Leveque, J., Netter, D., Douine, B., Rezzoug, A.
• 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: AC losses; Alternating current; Analytical models; Applied sciences; Bi-2223 current lead; Boundary conditions; Computer Science; Condensed Matter; COPPER ALLOYS (10 TO 40 CU); Current measurement; Electric connection. Cables. Wiring; Electric power; Electrical engineering. Electrical power engineering; Electromagnetism; Engineering Sciences; Equations; Exact sciences and technology; Heat transfer; HEATING; Magnetic materials; MATHEMATICAL ANALYSIS; Mathematical models; Modeling and Simulation; Nitrogen; Numerical models; over current; Physics; quench; QUENCHING MECHANISMS; Studies; Superconducting materials; SUPERCONDUCTIVITY; SUPERCONDUCTORS; Temperature dependence; Thermal coupling; Thermoelectricity; Transport; Various equipment and components; Temperature dependence; quench; Electrical conductivity; Critical value; Thermal behavior; Thermoelectric properties; Thermoelectric effect; Current carrying capacity; Critical current; Heating; Analytical method; over current; Electrical conductor; Bi-2223 current lead; AC losses; Comparative study; High temperature superconductor; Alternating current; temperature dependence
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2005.849149

When a superconductor is fed with an alternating current, the temperature rise created by the losses tends to reduce the current carrying capacity. If the amplitude of the current exceeds the value of the critical current, then the losses become particularly high and the thermal heating considerable. In this paper, a numerical and an analytical model which allow to estimate AC transport losses are presented. These models, which use the expression of I/sub c/(T) and n(T), are available for any applied current (below and above I/sub c/). The results are compared and the validity of the analytical model is considered. Then, the analytical formula allows to easily obtain the thermoelectric balance point of the system, when the losses and the temperature do not vary any more. Moreover, a maximum value of the current transport, beyond which the balance point does not exist, is detected. Indeed, when this maximum value is exceeded, the system is not stable and, say, superconducting current leads may quench.