| 摘要 |
PROBLEM TO BE SOLVED: To obtain a direct current breaker where the time to start opening a sub-breaker is controlled and thus the consumption of the electrode is reduced. SOLUTION: The direct current circuit, which comprises a main breaker 1 and the sub-breaker 2 which are serial-connected to the direct current circuit, and a capacitor 3 and a commutation switch 4 which are parallel-connected to the main breaker 1, comprises a commutation circuit 5 which superposes a reverse commutation current. The main breaker 1 is opened and the commutation current is supplied from the commutation circuit 5, and then a direct current is shut off between electrodes of the main breaker 1. When this direct current damps with a resistor of the direct current circuit and comes to a current zero, the sub-breaker 2 is made to be opened. COPYRIGHT: (C)2004,JPO
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