JP2982035B2 - Turbine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine control device, and more particularly to the control of a three-coil servo valve having control symmetry.
The present invention relates to a turbine control device for a thermal power plant, a nuclear power plant, or the like using a weighting controller.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional turbine control device having a triple system configuration. An increase / decrease operating device 50 is connected to each of the controllers 53 in the triple system configuration, and the set device output value of the setting device 51 is increased / decreased by a command signal from the increase / decrease operating device 50.
The arithmetic circuit 52 outputs a control command signal calculated based on the setter output value. The deviation between the control command signal and the feedback value from the valve opening detector 55 located downstream of the three-coil servo valve 40 is input to the servo amplifier 57,
The coil current of the coil servo valve 40 is controlled. Therefore,
Usually, the deviation that is a servo amplifier input signal is controlled so that the control command signal and the feedback value are equal,
The coil current of the three-coil servo valve 40 becomes zero. This 3
In the turbine control device having a multi-system configuration, the turbine control is set by increasing / decreasing the output of the setting unit 51 of each system by a command signal from the increase / decrease operating unit 50 by the operator. Therefore, the delay of the command signal from the increase / decrease operating device 50 to the setting device 51 of each system,
In addition, there is a delay in the calculation by the arithmetic circuit 52 of the three-system asynchronous controller, and this delay causes a difference between the setter outputs of the respective systems. During this time, the control command signal, which is the output of the three-system controller 53, is also generated. There was a problem that caused a difference.
Conversely, the configuration in which the output values of the setting devices are made uniform among the three systems has a problem that the independence of each system cannot be maintained as a triple system. Also, in a triple system, at the time of recovery and start-up after the system 1 controller is stopped, the systems already under control control the plant independently of each other, so that the control command signal output from the controller differs. However, in a triple turbine control device using a three-coil servo valve, a control command signal for that system is output at the same time as recovery and startup in such a state, and the system enters a control state.
Affects the plant directly. For this reason, in a system using such a three-coil servo valve, it is necessary to set a set value so that an appropriate control command signal is output at the time of start-up of recovery, and the complexity for setting the set value is reduced. there were. Further, as a known example, Japanese Patent Application Laid-Open No. Sho.
Discloses a turbine control device using a three-coil servo valve, but it is necessary to set a set value so that an appropriate control command signal is output when a system using the three-coil servo valve is started for recovery. No consideration has been given to

[0003]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a triple system turbine control device using a three-coil servo valve while maintaining the independence of each system as a triple system. If there is a difference between the output value of the setter of a certain system and that of the other two systems, adjust the value and adjust the setting of the setter so that there is no fluctuation in the plant after the start-up of the recovery after the stoppage of the first system. To provide a turbine control device.

[0004]

In a triple system using a three-coil servo valve, each system set value is different from a set target value set by an increase / decrease operating device in that a set target value of another set of two systems is set. If a deviation occurs from the value, and the value is equal to or more than a predetermined value, the set target value is regarded as abnormal and the output of the setter of this system is forcibly corrected to the average value of the other two systems. When the deviation is within a predetermined value, a tieback (signal follow-up) circuit is provided to make the output of the setter of each system equal to the set target value. Also, only two system 3 system contributes to the control, a remaining one system standby, when recovering startup to inject standby to the control system, 2 system in the control settings of the predetermined time standby together forcibly corrected to the mean value of the set target value, wait after a predetermined time
Make the system the same as the set target value of its own system, and only one of the three systems contributes to the control, and the remaining two systems are standby systems, and one of the two standby systems is put into the control system. When the recovery is started, the setting of the standby system is forcibly set to the set target value of the system under control for a predetermined time.
And set the standby system to its own system after a predetermined time.
Provide a tie-back circuit that is the same as the target value .

[0005]

The tie-back is forcibly performed only when the deviation between the set target value of the own system and the average of the set target values of the other two systems becomes equal to or larger than a predetermined value during the control of the third system . Therefore , it is possible to eliminate the difference between the setter output values of each system while maintaining the independence of each system as a triple system. Also, 1
At the time of recovery start-up after system stop, the setting of the standby system is forcibly corrected to the average value of the set target values of the two systems under control for a predetermined time or to the set target value of the system under control, so fluctuations in the plant may occur . The setting of the setting device can be adjusted so as not to give.

[0006]

Embodiments of the present invention will be described below. First, as an embodiment of the present invention, an outline of a nuclear turbine power plant is shown in FIG. In a nuclear power plant, steam generated from a reactor 21 as a turbine operating steam generation source passes through a main steam pipe 22, and is guided to a turbine body via a main steam stop valve 23 and a steam control valve (CV) 24. The steam worked in the high-pressure turbine 25 is supplied to an intermediate steam stop valve (IV).
After passing through 26, the steam that has been guided to the medium- and low-pressure turbine 27 and that has completed work in the medium- and low-pressure turbine is guided to the condenser 28, forming a so-called Rankine cycle. Further, a turbine bypass valve (TB) for directly guiding the generated steam to the condenser 28
V) having a bypass line according to 29; The turbine control device 30 includes a speed control-load control unit, a pressure control unit, a low value priority unit, a bypass valve control unit, a CV / IV control unit, and a T control unit.
It is composed of a BV control unit. Speed control-load control unit,
A turbine speed 31 and a generator output (not shown) are input, and a valve opening command is output. The pressure control unit has a steam pressure of 3
Input 2 and output the valve opening command. The low value priority section outputs a low value of both valve opening commands in order to ensure the safety of the turbine system. The bypass valve control section outputs a difference between the valve opening command of the pressure control section and the valve opening command of the low value priority section. The CV / IV control unit outputs a control signal to each of the CV and IV servo valves 40 in order to adjust the turbine speed, the generator output or the steam pressure in response to the valve opening degree command, and to open the valves CV24 and IV26. Control the degree. Further, the TBV control unit bypasses the generated steam in response to the valve opening degree command,
A control signal is output to the TBV servo valve 40, and the TBV 29
Of the valve is controlled.

FIG. 8 shows a speed-load control system (speed control-load control unit) of the turbine control device. This speed-load control system integrates the setting rate to the deviation value between the turbine speed set value and the actual speed, and increases or decreases the setter output value of the load setter 51 by the command signal of the increase / decrease operating device 50. The setter output value and the multiplied value are calculated in a calculation circuit 52 to output a control command signal for the valve opening. Here, the controller 53
Is composed of a load setting unit 51 and an arithmetic circuit 52.

FIG. 1 shows an embodiment of a turbine control device having a triple system configuration according to the present invention. The feature of the present invention is that the set target value and the setting device 5 which are increased or decreased by the increase or decrease operation device 50 in the configuration of FIG.
The tie-back circuit 61 for performing tie-back is added to FIG. FIG. 3 shows details of the tieback circuit 61. As shown, the tieback circuit 61 includes a deviation detector 70, an average value circuit 71, contacts a and b, and an AND circuit 8
0, an OR circuit 81, means 90 indicating that the system 3 is under control, and means 91 indicating within a predetermined time after the start-up.

Hereinafter, the operation of the tie-back circuit 61 will be described. First, the operation of the tie-back circuit 61 during the control of the third system will be described with reference to FIG. When the set target value of the own system is set to α by the increase / decrease operating device 50, the deviation between the set target value α and the value obtained by averaging the set target values β and γ of the other two systems by the averaging circuit 71 is calculated. Is greater than or equal to a predetermined value (A in FIG. 3).
The ND circuit 80) determines that the set target value α of the own system is abnormal, turns on the contact point a by the deviation detector 70, and turns off the contact point b.
Then, the output value of the setter of the own system is forcibly corrected to the average value of the set target values of the other two systems. On the other hand, when the aforementioned deviation is within a predetermined value, the contact point a is turned off by the deviation detector 70,
Since b is turned on, the output of the setting device of the own system becomes the same as the set target value of the own system. In this manner, the correction operation based on the average of the set target values of the other system can be provided in an abnormal state, and the independence of the triple system can be provided in the normal state.

Next, the operation of the tie-back circuit 61 at the time of restoring and starting up the third system after stopping the other system during the control of the second system will be described with reference to FIG. Here, when restoring and starting up the remaining one system during the two-system control, it is necessary to prevent fluctuations in the plant. Usually, in a triple system using a three-coil servo valve, as described in FIG. 2, the current for exciting the servo valve coil acts so that the sum of the current values of the three coils becomes zero. However, when the first system is stopped, the coil currents of the two systems under control have the same absolute value and different signs. This is caused by a deviation from a control command signal (there is a difference between the two systems) which is an output value of the two systems as a feedback value. At this time, the average value (intermediate value) of the second-system control command signal matches the feedback value. Therefore, when the stopped system 1 is restored and started, the coil current value is set to zero and the control system is turned on, and the stopped system 1 outputs the same output signal as the feedback value (at this time, the coil current value is output). Is reset to zero). That is, the control command value of the system for starting up the recovery is an average value of the two systems that are already under control. Therefore, in FIG. 5, when the setter output value of the system for restoration start-up is α, and when this system 1 is stopped and restored and started,
A predetermined time after startup (see the OR circuit 81 in FIG. 3), the contact a is turned on, and the contact b is turned off. During this time, the setter output value α of the system for starting up the recovery is forcibly corrected to a value obtained by averaging the set target values β and γ of the two systems that are already being controlled by the averaging circuit 71. After a lapse of a predetermined time, the contact a is turned off and the contact b is turned on, so that the output value of the setter of the own system is the same as the set target value of the own system. Also, the output of the setter of the second system under control becomes the same as the set target value of the own system. As a result, the coil current of the three-coil servo valve in the recovery start-up system becomes zero, and the effect on the plant can be prevented.

Next, the operation of the tie-back circuit 61 when only one of the three systems is under control and one of the remaining two systems is restored as the second system will be described with reference to FIG. I do. Also in this case, similarly to the above, it is necessary to keep the plant from fluctuating, and is based on the same concept as described above. However, when recovering and starting up one of the remaining two systems as the second unit, only one of the three systems is under control, and the feedback value of this one system matches the control command signal, and the coil current is reduced. Since it is zero, the output of the setter of one of the remaining two systems is made to match the output of the setter of the control system (the same as the target set value of that system). Therefore, in FIG. 6, when one of the remaining two systems is restarted after the stop, the contact a is turned on for a predetermined time after the start (see the OR circuit 81 in FIG. 3), and b is turned off. In the meantime, the setter output value α of the system at the start-up of the recovery is forcibly corrected to the set target value β of the system under control. After a predetermined time, a is turned off and b is turned on, and the output value of the setter of the own system becomes the same as the set target value of the own system. Also, the system under control becomes the same as the own system set target value. As a result, the coil current of the three-coil servo valve in the recovery start-up system becomes zero, and the effect on the plant can be prevented. In addition,
The input of the average value circuit 71 up to now has been only the set target values β and γ of the other system, but may be α, β and γ including the own system. Although not shown on the circuit, the set target value of each system is naturally made to coincide with the output value of the setter of the own system.

[0012]

As described above, according to the present invention,
During the control of the third system, the target value of the own system and the target value of the other two systems are set.
Mandatory only when the deviation from the average exceeds a specified value
Since so as to tie back to, while maintaining the independence of each system as a triple systems, it can be eliminated the difference between set output values for each system. At the time of recovery start-up after the suspension of the first system, the setting of the standby system is strongly influenced by the average value of the set target values of the second system during control for a predetermined time or the set target value of the system under control.
Since the correction is carried out regularly, the setting of the setting device can be adjusted so as not to cause a change in the plant. Also, in any system of the triple system, all the tie-back operations required by the triple system can be performed by the exactly same tie-back circuit, and the configuration as the system can be simplified.
You .

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a turbine control device having a triple system configuration according to an embodiment of the present invention.

FIG. 2 shows a conventional triple system turbine control device.

FIG. 3 shows details of a tie-back circuit according to an embodiment of the present invention.

FIG. 4 shows a tie-back during control of the third system according to the embodiment of the present invention.

FIG. 5 is a tieback at the time of starting up the 1st-system restoration during the 2nd-system control according to the embodiment of the present invention.

FIG. 6 shows a tie-back at the time of start-up of system 1 recovery from system 2 remaining during system 1 control according to the embodiment of the present invention.

FIG. 7 is an outline of a turbine control device for nuclear power.

FIG. 8 shows a speed-load control system of the turbine control device.

[Explanation of symbols]

 Reference Signs List 21 Nuclear reactor 24 Steam control valve 25 High pressure turbine 26 Intermediate steam stop valve 27 Medium / low pressure turbine 28 Condenser 30 Turbine control device 40 (3 coil) servo valve 50 Increase / decrease operating device 51 Setting device 52 Operation circuit 53 Controller 55 Valve position Detector 56 Servo valve coil 57 Servo amplifier 60 Setter target value 61 Tieback circuit 70 Deviation detector 71 Average value circuit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroyuki Takashima 5-2-1 Omikacho, Hitachi City, Ibaraki Prefecture Inside the Hitachi, Ltd. Omika Plant (56) References JP-A-60-221802 (JP, A) Kaisho 49-95308 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01D 17/00-21/00 G05B 7/02 G05B 9/03

Claims (3)

(57) [Claims] 1. A controller for outputting a control command signal for controlling a plant based on a set value, a servo amplifier for amplifying the control command signal, and a control system having a coil for driving a three-coil servo valve are tripled. The set target value of the own system and the set target value of the other two systems
The deviation from the average of the standard values is calculated, and this deviation is
In the above case, the set target value of the own system is regarded as abnormal and the
It is forcibly corrected to the average value of the fixed target value, while the deviation is
A turbine control device provided with a tie-back circuit that sets a set value of each system to be equal to a set target value of the system when the set value is within a predetermined value . 2. A control system having a controller for outputting a control command signal for controlling a plant based on a set value, a servo amplifier for amplifying the control command signal, and a control system having a coil for driving a three-coil servo valve is tripled. In the turbine control device, only two of the three systems contribute to the control, and the remaining one system is a standby system. At the time of restoration start-up in which the standby system is put into the control system, the standby system is used for a predetermined time. thereby forcibly correcting the set target value to the average value of two systems of setting target values in control, after a predetermined time setting target value of the own system to the standby system
A turbine control device comprising a tie-back circuit identical to that described above . 3. A control system having a controller for outputting a control command signal for controlling a plant based on a set value, a servo amplifier for amplifying the control command signal, and a control system having a coil for driving a three-coil servo valve is tripled. In the turbine control device, only one of the three systems contributes to the control, and the remaining two systems are standby systems. setting eyes of the standby system
The target value is forcibly corrected to the set target value of the system under control, and after a predetermined time, the standby system is set to the same as the set target value of the own system.
Turbine control device characterized by providing the tie-back circuit to scratch.