| 摘要 |
PURPOSE:To protect a superconductive power transmission cable and maintain a stable power supply by composing the cable of two sorts of conductors of different critical temperatures and using the cable by cooling it at a lower temperature than the two critical temperatures. CONSTITUTION:A superconductive power transmission cable 1 is composed of a superconductive wire 2 of a higher critical temperature and a superconductive wire 3 of a lower critical temperature attached to each other through insulating material 15. The two superconductive wires 2, 3 are cooled at a lower temperature than their critical temperatures by means of cooling agent 4, and the cooling agent 4 is supplied by a cooling device 5. A resistance measuring device 8 is connected with the superconductive wire 3 for an electric resistance to be measured. Because the resistance measuring device 8 also acts for a control signal generator, a signal 10 is produced immediately of a potential difference occurs, and a switch 9 is opened before the temperature of the cable reach the critical temperature of the conductor 2 to stop transmitting. Jule's heat is not produced, therefore, at the superconductive power transmission wire 2, and damage to the cable is prevented, thereby the cable can be protected. |
