| 摘要 |
PROBLEM TO BE SOLVED: To reduce costs for wire materials by connecting a superconducting current limiting resistor and a current limiting reactor in parallel, normally bypassing the current limiting reactor, applying a current to the current limiting reactor during the occurrence of an overcurrent, and connecting a rectifying bridge circuit to both the ends of this circuit. SOLUTION: A current limiting device 21 is constituted with a rectifying circuit 28 comprising a current limiting reactor 26, a superconducting current limiting resistor 27 and diodes D1 to D4. AC terminals 31 and 32 of a rectifying circuit 28 are connected to both the ends of a current limiting reactor 26, and DC terminals 33 and 34 are connected to both the ends of the superconducting current limiting resistor 27. At ordinary times, a current flows through a D1, the superconducting current limiting resistor 27, D3 or D2, the resistor 27 and D4 thereby bypassing the current limiting reactor 26. For example, if a short- circuit occurs at a position 25 and an overcurrent flows to the superconducting resistor 27, then quenching occurs and normal conduction restarts, an overcurrent flows to the current limiting reactor 26, and heating of the resistor 27 is suppressed. By doing this, a low-priced DC wire materials can be used for the superconducting resistor thereby realizing low costs. |
