JPS63105204A - Control device for steam turbine - Google Patents

Abstract

PURPOSE:To improve the reliability of a turbine plant, by generating an emergency alarm signal and a trip signal, if a deviation between a steam valve opening preset value and an actual valve opening lasts longer than a given time in excess of a given value. CONSTITUTION:An opening demand signal 1 by a steam valve 6 and an actual opening signal 10 detected by an opening detector 8 are entered into an adding machine 11 for comparing a deviation signal 12 generated thereby with a preset value in a setting device 13 by means of a comparator 14. The generation of the deviation signal 12 lasting in excess of the preset value for the time set by a timer 16 will result in the closing of a contact 16 so as to allow an emergency alarm 17, a backup pump starting signal generator 18, a trip signal generator 19, etc., to be operated. The aforesaid constitution will enable an emergency in a turbine plant to be detected so as to prevent an accident and so on in advance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a steam turbine control device for controlling a water pump that supplies water to a steam generating device such as a boiler or a nuclear reactor in a thermal or nuclear power plant.

(Prior art) In general, in thermal or nuclear power plants, a steam valve that controls the amount of steam flowing into the steam turbine that drives the water pump that supplies water to the steam generators such as boilers and nuclear reactors is installed. ing.

This steam valve controls the amount of steam according to the load of the generator, the rotational speed of the turbine, etc., and its control device is constructed as shown in FIG.

In the figure, a steam valve opening request signal 1 is sent in response to a water supply command or water supply request from a water supply pump to a steam generator (not shown).
(electrical signal) is converted into a mechanical displacement by an electro-hydraulic converter 2 and transmitted to a signal transmission lever system 4 via an adder 3. The signal from the signal transmission lever system 4 is powered up by the oil cylinder 5 and controls the opening degree of the steam valve 6.

Further, the output of the oil cylinder 5 is fed back to the adder 3 via the feedback lever system 7. The adder 3 compares this feedback signal with the valve opening request signal, and if a deviation occurs between them, it transmits this to the signal transmission lever system 4.

As a result, control is performed by the oil cylinder 5, and the control system becomes stable when the valve opening request signal and the steam valve actual opening match.
It is statically settled in a steady state.

(Problems to be Solved by the Invention) In the steam turbine control device having such a configuration, if an abnormality occurs due to some cause, for example, stiffness of the steam valve sliding part due to oxidized scale, dirt or dust in the air, etc. Or, if the lever system becomes stuck due to rust caused by water vapor, etc., the valve may not open or close in response to the valve opening request signal, signal transmission in the lever system may be delayed, or the movement of the connection may become slippery. This may cause the phenomenon of loss of strength.

In such a case, the oil cylinder 5 and the steam valve do not operate in response to the opening request signal, or there is a delay in their operation, and the steam flowing into the steam turbine fluctuates. As a result, fluctuations occur in the amount of water supplied to steam generators such as boilers and nuclear reactors.

Also, if the lever system stops operating during valve opening operation,
Since the valve opening is no longer fed back and the valve is opened more than the opening request signal, the steam turbine may reach overspeed.

In addition, even if the lever system stops moving during valve closing, the actual opening of the steam valve will no longer be fed back, and the valve will be fully closed and will not open even in response to the opening request signal "increase". A drop in water supply could lead to a reactor scram.

In this way, in the conventional steam turbine control device,
Even if an abnormality occurs in the control system, the backup pump will not start unless the system trips, resulting in problems such as reactor scrams, overspeeding, and hunting in the control system due to a drop in water supply.

[Structure of the invention]

(Means for Solving the Problems) The steam turbine control device of the present invention converts a steam valve opening request signal into a mechanical signal using an electro-hydraulic converter, compares this with a signal from a feedback lever system, In a steam turbine control device that transmits a deviation signal obtained by this comparison to a steam valve via an oil cylinder, an actual opening degree signal corresponding to the actual opening degree of the steam valve is added together with an opening request signal. In addition to the device, the obtained deviation signal is guided to a comparator together with the signal from the setting device, and the output of this comparator is manually input to the abnormality alarm generator and trip signal generator via a timer. That is.

(Function) In the steam turbine control device of the present invention configured as described above, when an abnormality occurs in the control system, the abnormality is detected and an alarm is generated, and at the same time, the steam turbine in which the abnormality has occurred is tripped. Additionally, if a backup water pump is installed, it will be activated to prevent the reactor from shifting to scram.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings. In addition,
In FIGS. 1 and 2, the same parts as in FIG. 3 are designated by the same reference numerals, and detailed explanations will be omitted.

In FIG. 1, the output of the oil cylinder 5 is detected by the opening detector 8, and the actual opening signal (electrical signal) 10 is sent by the converter 9.
is converted to This actual opening signal 10 is led to an adder 11 together with an opening request signal 1, and a deviation signal 12 outputted from this adder is sent to a comparator 14 together with a setting value from a setting device 13.
is input.

The output 15 of the comparator 14 is sent via a timer 16 to an abnormality alarm generator 17, a backup pump start signal generator 18,
and is input to the trip signal generator 19.

In the steam turbine control device of the present invention configured as described above, the steam valve opening request signal 1 (electrical signal) is converted into a mechanical displacement by the electro-hydraulic converter 2, as in the case of FIG. , are transmitted to the signal transmission lever system 4 via the adder 3. The signal from the signal transmission lever system 4 is powered up by the oil cylinder 5 and controls the opening degree of the steam valve 6. The output of the oil cylinder 5 is sent to the adder 3 via the feedback lever system 7.
will be returned to. The adder 3 compares this feedback signal with the valve opening request signal, and if a deviation occurs between them, it is transmitted to the signal transmission lever system 4, and control is performed by the oil cylinder 5, and the valve opening is changed. When the request signal and the actual steam valve opening match, the control system is stabilized and settled into a steady state.

On the other hand 1. The actual opening degree of the steam valve is detected by the opening degree detector 8, and after being converted into an electric signal by the converter 9, the adder 1
1, the actual opening is compared with the opening request signal l, and if the deviation signal 12 is positive and larger than the positive setting value X stored in the setting device 13, the actual opening is abnormal with respect to the opening request signal. In addition, when the deviation signal 12 is negative and the value is smaller than the negative set value -X, it is detected that the actual opening of the steam valve is abnormal with respect to the opening request signal. and outputs an abnormal signal 15.

That is, as shown in FIG. 2, in a normal state, the actual opening of the valve in response to the opening request signal is the required opening - actual opening curve 2.
If the motor is operated at a position above 0 and an abnormality occurs that exceeds range C, which is determined by taking into account delays during transitions,
When the deviation 12 is positive, the range is "a", and when the deviation 12 is negative, the range is "b", and the abnormal signal 15 is output.

The timer 16 closes the contact 16 when the abnormal signal 15 continues even after a predetermined time has elapsed in consideration of the delay time of the control system.
a is closed, and an abnormality signal 15 is output to the abnormality alarm generator 17, backup pump start signal generator 18, and trip signal generator 19.

In this way, if the feedback signal of the actual opening lags behind the opening request signal by more than the delay time of the control system or does not follow the opening request signal, the abnormality signal 15 is output from the abnormality alarm generator 17. In addition to outputting an alarm, the backup pump is activated by a signal from the backup pump activation signal generator 18, and at the same time, it is tripped to protect the steam turbine. This allows the occurrence of abnormal situations to be ascertained and at the same time prevents the occurrence of reactor scrams, etc.

Note that the present invention is not limited to the above-described embodiment, and instead of the opening signal of the steam valve, signals corresponding to the actual opening of the steam valve, such as the rotation speed of the steam turbine, the steam flow rate, the pump discharge flow rate, etc., may be detected. This may be used as the actual opening signal 10 and compared with the opening request signal, and an abnormality signal 15 may be output.

〔Effect of the invention〕

As described above, in the steam turbine control device of the present invention, an abnormality in the control device is detected early, an abnormality alarm is outputted, the turbine is tripped, and a backup device is activated as necessary. Therefore, it is possible to prevent troubles from occurring in the steam turbine plant and improve reliability.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of the present invention, FIG. 2 is a graph showing the operation of the device of the present invention, and FIG. 3 is a system diagram illustrating a conventional steam turbine control device. 1... Opening request signal, 2... Electro-hydraulic converter, 3.11
... Adder, 4... Signal transmission lever system, 5... Oil cylinder, 6... Steam valve, ... Feedback lever system,
8... Opening degree detector, 9... Converter, 10... Actual opening degree signal, 12... Deviation signal, 13... Setting device, 14
... Comparator, 15 ... Abnormal signal, 16 ... Timer, 17 ... Abnormal alarm generator, 18 ... Backup pump start signal generator 18. One ... Trip signal generator, 20...Required opening-actual opening curve. Applicant's agent Sato - Yu 1 Sumani 1 Fig. 1 Key signal signal Fig. 2 Ka 3 items

Claims (1)

[Claims] 1. Convert the steam valve opening request signal into a mechanical signal using an electro-hydraulic converter, compare this with the signal from the feedback lever system, and use the deviation signal obtained by this comparison to In a steam turbine control device that transmits a signal to a steam valve via a steam valve, an actual opening signal corresponding to the actual opening of the steam valve is added to an adder together with an opening request signal, and the obtained deviation signal is set. 1. A control device for a steam turbine, characterized in that the control device is configured to lead a signal from a steam turbine to a comparator together with a signal from the steam turbine, and input the output of the comparator to an abnormality alarm generator and a trip signal generator via a timer. 2. The steam turbine control device according to claim 1, wherein the output of the comparator is configured to be input to a backup pump start signal generator via a timer.