| 摘要 |
PURPOSE:To simplify the whole current-limiting apparatus by constituting said apparatus from a high temperature oxide superconductor changing from a superconductive state to an ordinary conductive state, when a short-circuit current flows therethrough, and a current-limiting resistor connected in parallel with said superconductor. CONSTITUTION:Because a current-limiting element 1 is cooled by liquid hydrogen, the electric resistance of a superconductor 3 is ordinarily zero and power is applied to only said superconductor 3. In said state, when a system trouble occurs and a short-circuit current flows and exceeds the critical current of said superconductor 3, the superconductor 3 changes from a superconductive state to an ordinary conductive state and the resistance value increases so that the short-circuit current flows not only through the superconductor 3 but also through the current-limiting resistor 4 after divided into two currents. Consequently, the temperature of said current-limiting resistor 4 rises and the resistance value increases. As a whole, therefore, the current-limiting element 1 works as a series resistance on said system trouble to limit said short-circuit current. |
