| 摘要 |
PROBLEM TO BE SOLVED: To provide an open-phase detector of a receiving/distributing facility, which prevents an abnormal operation with a switch after open-phase detection. SOLUTION: When first progress information t1 to be measured in a state where a line voltage V is lower than an open-phase voltage set value V1 becomes an open-phase judgement set value T1 during a first predetermined period S1, the open-phase detector 20 judges that open phase occurs with a switch in a receiving/distributing facility side and opens the switch. When second progress information t2 to be measured in a state where the line voltage exceeds the open-phase voltage set value becomes an open-phase recovery judgment set value T2 in a period from judgement of open phase to elapse of a second predetermined period S2, the detector 20 judges that open-phase is recovered and turns on the switch. The open-phase detector 20 is provided with a second progress information measurement inhibiting means 25 for setting a measurement inhibiting period S0 which is longer than a period from judgement of open phase to elapse of the period S2 and in which the progress information t2 to be measured in the state where the line voltage exceeds the open-phase voltage set value does not become the open-phase recovery judgement set value T2, and preventing measurement of the progress information t2 during the measurement inhibiting period. COPYRIGHT: (C)2009,JPO&INPIT
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