| 摘要 |
PURPOSE:To prevent an abnormal rise in the voltage/frequency ratio by a method wherein a hydraulic turbine and a dynamotor are put out of operation in an emergency action and a voltage at the dynamotor terminals higher than a prescribed value causes the exciting current to be interrupted when input is lost. CONSTITUTION:When input is interrupted while a dynamotor 1 is in operation as a synchronous motor, an input loss detector 12 is activated, yielding an emergency stop directive. The hydraulic turbine is stopped and parallellism-forming breaker 4 is opened. Failure of the breaker 4 to open causes a field breaker 9 to remain closed, when voltage across the terminals of the hynamotor is maintained at a rated value by means of an automatic voltage regulator 6. Under such conditions, a voltage detecting relay 14 stays in operation, which, after the elapse of a prescribed period of time, causes a gate shut-off directive to be supplied to the automatic voltage regulator 6, which in turn stops an exciting rectifier 8 from controlling the gate. |
