To enable an abnormal state in a steam generating device to be diagnosed in an easy and accurate manner by a method wherein an output from a memory means is received when a presence or a non-presence of abnormal state is diagnosed, an output from a calculating means for calculating a coefficient vector of a pseudo transfer function of the steam generator with a coefficient vector under a normal state and an abnormal signal is outputted when a difference between them is more than a predetermined value.
When an abnormal state is diagnosed, a signal generator receives a diagnosing control instruction from a control device 21 and sends an M-series signal 23s to an adder 7. In the adder 7, a signal 23s which may become a disturbance of zero of mean value having a larger amplitude than that of noise of a corrected control signal is added, and output is performed. PI2 controller 6 receives this output, performs a PI calculation, and sends it as a control signal including the disturbance to a water supplying control valve 5 so as to maintain a water level. A pseudo function calculating device 25 inputs a water supplying flow rate signal 4s and a water level signal 2s from a memory device 24 and then attains a predetermined pseudo transfer function of the steam generating device with a method of least squares. An a normal state presence or non-presence discriminating device 26 receives these signals, output an abnormal signal, and then the display device 27 may generate an abnormal display and an alarm in reference to these signals.
TERANISHI SUSUMU
FUJIWARA TOSHIKATSU
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