| 摘要 |
<p>PURPOSE:To previously prevent a unit trip by continuously supervising the change of amplitude in the hunting state of a feedback signal in a feedback control system, judging it to be a divergent hunting state when amplitude is in an increase direction by more than a specified value, giving an alarm and saving the control system to a safe direction such as a manual mode. CONSTITUTION:A turbine at the time of loading, the switching of motor driving/ water supply pumps 7 and 8 and fluctuation of water supply when recirculation pumps 26-28 are closed influence the control, for example. Namely, the sudden change of a sawtooth water supply quantity 20 when the valves are opened comes to the disturbance of the feedback control system but it is normally arranged at once. If a plus error occurs owing to the other cause and if the correction of an opening command 21 and the actual mechanical operation timing of the valves are shifted when the valves 26-28 are opened, the water supply quantity 20 becomes divergent hunting state, and the unit may trip. Thus, an abnormality diagnostic circuit 29 where the water supply quantity 20 being the feedback signal of the control system is set to be input is added and the alarm is generated at an initial stage.</p> |
