| 摘要 |
PURPOSE:To prevent power interruption fault by tripping a loop switcher prior to trip operation of an overcurrent relay in a substation when lateral loop flow is detected. CONSTITUTION:Upon throw-in of a loop point switchgear SW 3, loop current flows laterally through a distribution line. When the lateral loop current is larger then the load current in a predicted line, it is detected through the overcurrent transformer 24 of a loop switcher SW2. A detection signal is fed to a relay 3e, which then produces an interruption trip signal. The interruption trip signal is not locked but fed, as it is, from the relay 3a to the operational mechanism 17 in a switchgear 2. The operational mechanism 17 receives the interruption trip signal and makes (breaks) a contact 2e immediately. The breaking operation is coordinated to be carried out prior to the trip operation of the overcurrent relay in a substation, and thereby the circuitbreaker in the substation is not tripped. |
