Temperature rise in a superconducting cable during overload

✍ Scribed by P.H. Melville

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 391 KB
• Volume: 15
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(75)90115-0

✦ Synopsis

Approximate calculations are presented for the temperature rise and temperature fluctuation in an ac superconducting cable during current overload. The calculations are for a cable, which it is intended will remain superconducting throughout the overload. These show that because of the low value of T c and low Jc niobium-titanium is not a suitable material to use. Niobium-zirconium with a 1 mm copper backing will carry continuous overloads of up to x 9 and a first cycle overload of up to x 11 provided it is fully stabilized against flux jumps. (Normal surface current rating = 4 x 104 A m-1). Niobium-tin can in principle carry very large overloads, but the limiting factors are its poor mechanical properties, the difficulty in producing thick layers of the material, and stabilization.

Temperature rise in a superconducting cable during overload P. H. Melville

Under normal operating conditions the hysteresis losses for most designs of ac superconducting cable are not sufficient to raise the conductor temperature much above the temperature of the supercritical helium used for cooling. However, when the cable is carrying an overload, the conductor temperature can rise appreciably. Obviously if the cable is to remain superconducting throughout the overload the temperature cannot be permitted to rise too far. In the work reported here estimates are given for the temperature rise for various overloads to establish the maximum overload that can be carried by different types of superconductor.