| 摘要 |
PROBLEM TO BE SOLVED: To provide a power switching apparatus which can effectively prevent reignition from occurring during power-off process while cost and size are suppressed to increase. SOLUTION: The power switching apparatus includes: a circuit breaker connected between a power circuit and a load circuit; a current measurement unit which measures current flowing between the power circuit and the circuit breaker; a phase-controlled switching unit which predicts a current zero point of each phase current so as to execute phase-controlled switching; and an operation device which concurrently drives contactors of a three-phase arc-extinguishing chamber provided in the circuit breaker, wherein when shutting off load current including small capacitive current, the phase-controlled switching unit assumes a point where one phase out of three phases reaches the current zero point, as reference time, and controls the operation device such that each contactor of the circuit breaker is switched to opening state during a period from the reference time to a range of an electric angle of 20-40 degrees. COPYRIGHT: (C)2009,JPO&INPIT
|
