| 摘要 |
PURPOSE:To improve resistance to systematic disturbance of the titled plant by setting the limit value of the derivative of a request signal of a flow rate in an add-subtract valve which is sent to a computing unit of a bypass valve control signal in order to maintain this request signal at a certain level during a certain time after the reset of a power load unbalanced relay. CONSTITUTION:The load setting signal 14 is added 57 to the signal from a speed adjuster 11. This added signal 13 is inputted to a prior circuit of the low value 26 and compared with signals 31, 5 from a speed load limiter 30 and a pressure adjuster 4 and the lower signal is outputted as a request signal 27 for flow rate in the add-subtract valve. Request signal for flow rate of a bypass valve 7 is computed by subtracting the request signal 27 for flow rate of the add-subtract valve from a total flow rate signal of main steam 5. In this time, the derivative of the subtract signal is limited by a derivative limiter 32. During a certain time after the reset of a power load unbalance relay 23, a speed load setting signal 31 is maintained at zero and the request signal 27 for flow rate of the add-subtract valve is also maintained at zero and only the bypass valve is throttled.
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