JPH0772487B2 - Boiler governor valve controller - Google Patents

Description

The present invention relates to a governor valve control device for a boiler.

[Prior Art] A conventional boiler governor valve control device will be described with reference to Figs. 6 to 9.

In the figure, 1 is a boiler, 2 is a steam flow path for sending steam generated by the boiler 1 to a turbine 3, 4 is a generator driven by the turbine 3, and 5 is a flow rate of steam provided in the middle of the steam flow path 2. Governor valve for adjusting, 6 is a boiler 1 of the steam flow path 2
, A pressure gauge 7 provided between the governor valve 5 and the governor valve 5, and a generator 4
Is an output meter provided in.

Reference numeral 8 is a fuel valve for supplying fuel to the boiler 1, and 9 is a water supply valve for supplying water to the boiler 1.

10 is an output command sent to the boiler 1, 11 is an output command 10 and a correction signal 12 described later are added, and the fuel valve 8 and the water supply valve 9 are added.
Is an adder for obtaining a boiler master signal 13 for controlling the.

When the output command 10 is input, 14 outputs the output command 10 based on a preset function F ₁ (x) as shown in FIG. 7, for example.
Is a function generator that generates a steam pressure setpoint 15 corresponding to. Reference numeral 16 is a steam pressure detection signal 17 indicating the pressure of steam flowing through the steam flow path 2 detected by the pressure gauge 6, and the function generator.
It is a subtracter that obtains a steam pressure deviation signal 18 by taking the deviation from the steam pressure set value 15 output by 14. 19 receives the steam pressure deviation signal 18 from the subtractor 16 and inputs the steam pressure deviation signal 18
Is a controller for obtaining a correction signal 12 to be output to the adder 11 based on

Reference numeral 20 is a subtractor that takes the deviation between the output command 10 and the generator output signal 21 indicating the output of the generator 4 detected by the output meter 7 and obtains the generator output deviation signal 22. 23 is a generator output deviation signal 22 and the steam pressure deviation signal 18 is input, while the steam pressure deviation signal 18 is within a preset allowable range, the generator output deviation signal 22 is output, Steam pressure deviation signal
An override circuit for signal switching that outputs a steam pressure deviation signal 18 when 18 exceeds the allowable range. 24 receives the generator output deviation signal 22 or the steam pressure deviation signal 18 output from the override circuit 23 and outputs the generator output deviation signal 22.
Alternatively, the controller outputs an opening / closing signal 25 for adjusting the opening degree to the governor valve 5 based on the steam pressure deviation signal 18.

Next, the operation will be described.

First, the output command 10 is sent to the boiler master signal via the adder 11.
It is converted into 13, and the opening degree of the fuel valve 8 and the water supply valve 9 is adjusted by the boiler master signal 13 to control the amount of fuel and water supplied to the boiler 1.

In this way, the fuel and water supplied to the boiler 1 burn and generate steam in the boiler 1.

The steam generated in the boiler 1 is supplied to the turbine 3 through the steam flow path 2, drives the turbine 3, and causes a generator 4 connected to the turbine 3 to generate power.

The pressure of the steam flowing through the steam flow path 2 is detected by the pressure gauge 6, and the steam pressure detection signal 17 is output to the subtractor 16.
On the other hand, the output command 10 is the function generator 14 and the function F _{1 of} FIG.
Based on (x), the steam pressure set value 15 is converted, and the steam pressure set value 15 is output to the subtractor 16. The subtracter 16 takes a deviation between the input steam pressure set value 15 and the steam pressure detection signal 17, and the deviation is used as a steam pressure deviation signal 18 for the controller 19
Then, the controller 19 outputs the correction signal 12 to the adder 11 based on the steam pressure deviation signal 18. The adder 11 adds the correction signal 12 to the output command 10 to generate a new boiler master signal 13, and controls the fuel valve 8 and the water supply valve 9 as described above. Therefore, the opening degrees of the fuel valve 8 and the water supply valve 9 are corrected according to the fluctuation of the pressure of the steam flowing through the steam flow path 2.

On the other hand, the output of the generator 4 is detected by the output meter 7,
The generator output signal 21 is output to the subtractor 20. The subtractor 20 takes a deviation between the generator output signal 21 and the output command 10, and outputs the deviation as a generator output deviation signal 22 to the override circuit 23. The override circuit 23 inputs the generator output deviation signal 22 and the steam pressure deviation signal 18, and in a normal time, that is, when the steam pressure deviation signal 18 is within the allowable range set in advance in the override circuit 23, the generator output deviation signal. 22 adjuster
When the steam pressure deviation signal 18 exceeds the allowable range set in advance in the override circuit 23, the steam pressure deviation signal 18 is output to the controller 24. In the regulator 24, based on either the generator output deviation signal 22 or the steam pressure deviation signal 18 from the override circuit 23, an open / close signal is sent to the governor valve 5.
25, the opening degree of the governor valve 5 is adjusted to control the flow rate of the steam supplied to the turbine 3 through the steam flow path 2.

Therefore, while the vapor pressure deviation signal 18 is within the tolerance range preset in the override circuit 23, the override circuit
The opening degree of the governor valve 5 is adjusted based on the generator output deviation signal 22 output from the controller 23 to the regulator 24. Therefore, the governor valve 5 controls the output of the generator 4.

As a result of the output control of the generator 4, the generator output deviation signal 22 is
As shown in FIG. 8, it is kept within a predetermined allowable range b.

However, since the response speed of the steam pressure control using the fuel valve 8 and the water supply valve 9 by the boiler master signal 13 is slower than the steam pressure change speed by the operation of the governor valve 5, the fluctuation of the generator output deviation signal 22 is large. In this case, the governor valve 5 may move greatly and the steam pressure deviation signal 18 may fluctuate, and steam pressure control by the boiler master signal 13 may not be in time.
In this state, the steam pressure deviation signal 18 may be further increased to exceed the allowable range (b) in FIG. 9, and the state of the boiler 1 may become unstable.

Therefore, when the steam pressure deviation signal 18 exceeds the allowable range B preset in the override circuit 23 (9th
(C), the override circuit 23 is switched to the steam pressure deviation signal 18 side, and the opening degree of the governor valve 5 is adjusted based on the steam pressure deviation signal 18.

Then, if the pressure control of the generator 4 is left as it is, as shown by the dotted line D in FIG. 9, it is forced that the steam pressure deviation signal 18 goes far beyond the allowable range B, as shown by the chain line E. Of the steam pressure deviation signal 18 is kept within the allowable range b.

In this way, by keeping the steam pressure deviation signal 18 within the allowable range (b), the pressure of the steam flowing through the steam flow path 2 is prevented from becoming too low or too high.

When the steam pressure deviation signal 18 is returned within the allowable range (b), the output control of the generator 4 is switched again.

[Problems to be Solved by the Invention] However, the conventional governor valve control device for a boiler described above has the following problems.

When the steam pressure deviation signal 18 exceeds the allowable range B preset in the override circuit 23, the governor valve 5 suddenly switches from the output control of the generator 4 to the steam pressure control, and the steam pressure deviation signal 18 is allowed. When the range B is exceeded, the opening / closing operation is suddenly made to cause a rapid change in the pressure of the steam flowing in the steam flow path 2. Therefore, as described above, the boiler master signal is generated.
Since 13 is suddenly disturbed, and the disturbance of the boiler master signal 13 becomes a disturbance to hinder the stable combustion state of the boiler 1,
Once the steam pressure control was performed, it took a long time until the combustion of the boiler 1 was stabilized again.

In view of the above situation, the present invention can solve the above problems by performing generator output control corrected by steam pressure control before switching from generator output control to steam pressure control. It is an object of the present invention to provide a governor valve control device for a boiler.

[Means for Solving the Problems] The present invention is a pressure gauge 6 for detecting a pressure of steam in a steam flow path 2 for sending steam from a boiler 1 to a turbine 3 to obtain a steam pressure detection signal 17, and a steam pressure detection signal. 17 and a subtracter 16 for obtaining a steam pressure deviation signal 18 by taking a deviation between the steam pressure set value 15 obtained based on the output command 10 of the boiler 1, and a function generation for obtaining the correction coefficient 27 by inputting the output command 10 Vessel 26,
A multiplier 28 for obtaining the steam pressure deviation correction signal 29 by multiplying the steam pressure deviation signal 18 and the correction coefficient 27, and a function generator 30 for inputting the steam pressure deviation correction signal 29 to obtain the generator output deviation correction signal 31. , The output meter 7 for detecting the output of the generator 4 driven by the turbine 3 to obtain the generator output signal 21, and the difference between the generator output signal 21 and the output command 10 to obtain the generator output deviation signal 22. A subtractor 20 for calculating the generator output deviation signal 22, an adder 32 for adding the generator output deviation correction signal 31 to the corrected generator output deviation signal 33, the steam pressure deviation signal 18 and the corrected generator While the output deviation signal 33 is input and the steam pressure deviation signal 18 is within the preset allowable range b, the corrected generator output deviation signal 33 is output and the steam pressure deviation signal 18 is outside the allowable range b. When the steam flow deviation signal 18 Override circuit for controlling the governor valve 5 to adjust the flow rate of the steam flowing in the 2
The present invention relates to a governor valve control device for a boiler, which is provided with 23.

[Operation] The subtractor 16 outputs the steam pressure detection signal 17 indicating the pressure of the steam in the steam flow path 2 detected by the pressure gauge 6 and the output command of the boiler 1.
The steam pressure deviation signal 18 is obtained by taking the deviation from the steam pressure set value 15 obtained based on 10.

The function generator 26 inputs the output command 10 and outputs a correction coefficient 27
Ask for.

The multiplier 28 multiplies the steam pressure deviation signal 18 and the correction coefficient 27 to obtain a steam pressure deviation correction signal 29.

The function generator 30 inputs the steam pressure deviation correction signal 29 and obtains a generator output deviation correction signal 31.

The subtracter 20 takes the deviation between the generator output signal 21 indicating the output of the generator 4 detected by the output meter 7 and the output command 10,
Determine the generator output deviation signal 22.

The adder 32 adds the generator output deviation correction signal 31 to the generator output deviation signal 22 to obtain a corrected generator output deviation signal 33.
Ask for.

The override circuit 23 inputs the steam pressure deviation signal 18 and the corrected generator output deviation signal 33, and outputs the correction generator output deviation signal while the steam pressure deviation signal 18 is within a preset allowable range (b). 33 is output, and when the steam pressure deviation signal 18 is out of the allowable range b, the steam pressure deviation signal 18 is output to control the governor valve 5 for adjusting the flow rate of the steam flowing through the steam flow path 2. .

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show an embodiment of the present invention, in which the portions denoted by the same reference numerals as those in FIGS. 6 to 9 represent the same things, and therefore the explanation thereof will be omitted.

Reference numeral 26 in the figure is a function generator which, when the output command 10 is input, generates a correction coefficient 27 corresponding to the output command 10 based on a preset function F ₂ (x) as shown in FIG. 2, for example. . 28 is a multiplier for multiplying the steam pressure deviation signal 18 by the correction coefficient 27 to obtain a steam pressure deviation correction signal 29. When the steam pressure deviation correction signal 29 is input to the steam generator 30, the generator output deviation correction signal 31 is 0 when the steam pressure deviation correction signal 29 is in a small range as shown in FIG. When the signal 29 is in a range exceeding the above range, the steam pressure deviation correction signal 29 is generated based on the function F ₃ (x) in which the generator output deviation correction signal 31 has a value proportional to the steam pressure deviation correction signal 29. Is a function generator for generating a generator output deviation correction signal 31 corresponding to. 32 is a subtractor 20 and an override circuit 23
The generator output deviation signal 22 and the generator output deviation correction signal 31 are added to correct the generator output deviation signal.
It is an adder that obtains 33 and outputs the corrected generator output deviation signal 33 to the override circuit 23.

In the present invention, the corrected generator output deviation signal 33 instead of the output deviation signal 22 is supplied from the override circuit 23 to the controller.
It is output to 24.

Next, the operation will be described.

The operation of controlling the fuel valve 8 and the water supply valve 9 by obtaining the boiler master signal 13 and the operation of performing the steam pressure control by the governor valve 5 are performed in the same manner as in FIGS. 6 to 9.

When the output control of the generator 4 is performed by the governor valve 5, the output command 10 is the function generator 26 and the function F ₂ (x) shown in FIG.
Is converted to a correction coefficient 27 based on the above, and the correction coefficient 27 is output to the multiplier 28. The multiplier 28 multiplies the input steam pressure deviation signal 18 by the correction coefficient 27 to obtain the steam pressure deviation correction signal 29, and the steam pressure deviation correction signal 29 is fed to the function generator 30 to obtain the function F shown in FIG. Based on ₃ (x), it is converted into a generator output deviation correction signal 31. The generator output deviation correction signal 31 is added to the generator output deviation signal 22 by an adder 32 to form a corrected generator output deviation signal 33, and the corrected generator output deviation signal 33 is output to the override circuit 23. Thus, output control of the generator 4 by the governor valve 5 is performed based on the corrected generator output deviation signal 33.

In this way, when the output control of the generator 4 is performed by the governor valve 5 based on the corrected generator output deviation signal 33, the absolute value of the steam pressure deviation signal 18 becomes small, and the steam pressure deviation correction signal 29 of FIG. When takes a value within the range, the generator output deviation correction signal 31 generated by the function generator 30 becomes 0, so that the adder 32 outputs the generator output deviation correction signal 22 to the generator output deviation correction signal.
The value of the corrected generator output deviation signal 33 to which 31 is added becomes substantially the same value as the generator output deviation signal 22. Therefore, the governor valve 5 causes the conventional generator 4 as shown in FIG. Output control is performed.

When the absolute value of the steam pressure deviation signal 18 becomes large and the steam pressure deviation correction signal 29 shown in FIG. 3 takes a value in the range, the function generator 30 generates a generator proportional to the steam pressure deviation correction signal 29. Since the output deviation correction signal 31 is generated, the adder 32
The value of the corrected generator output deviation signal 33 obtained by is larger or smaller than the actual generator output deviation signal 22 by the generator output deviation correction signal 31. Therefore, in the governor valve 5, the generator output deviation signal 33 becomes larger. Based on the corrected generator output deviation signal 33 which is larger or smaller than the deviation signal 22, the output control of the generator 4 is performed and the steam pressure is controlled at the same time.

Therefore, the steam pressure deviation signal 18 is transmitted to the override circuit 23.
When the value approaches the allowable range b set in
The output control of the generator 4 is performed based on the corrected generator output deviation signal 33 in which the actual generator output deviation signal 22 as described above is corrected by the generator output deviation correction signal 31, and as a result,
The control accuracy for the output control of the generator 4 is reduced by the amount corrected by the generator output deviation correction signal 31, and as shown in FIG.
Although larger than in the case of the figure, instead, as shown in FIG. 5, the steam pressure deviation signal 18 is kept within the allowable range b, and the steam pressure control is strengthened.

Therefore, the output of the override circuit 23 suddenly switches to the steam pressure deviation signal 18, causing a sudden change in the pressure of the steam flowing through the steam flow path 2, disturbing the boiler master signal 13, and stabilizing the combustion of the boiler 1. Interfering with the condition is prevented.

The governor valve control device for a boiler according to the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[Effects of the Invention] As described above, according to the governor valve control device for a boiler of the present invention, the steam pressure deviation correction signal 29 is multiplied by the steam pressure deviation signal 18 and the correction coefficient 27 corresponding to the output command 10. Seeking,
From the steam pressure deviation correction signal 29, a generator output deviation correction signal
31 is obtained, the generator output deviation correction signal 31 is added to the generator output deviation signal 22 to obtain a corrected generator output deviation signal 33, and the governor valve 5 is controlled based on the corrected generator output deviation signal 33. Therefore, the steam pressure deviation signal 18 of the steam flowing through the steam flow path 2 is prevented from exceeding the allowable range (b). Therefore, sudden switching to the steam pressure control disturbs the boiler master signal 13 to stabilize the combustion state of the boiler 1. Is prevented, and the boiler 1 can always be maintained in a stable combustion state.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the output command 10 and the correction coefficient 27, and FIG. 3 is a steam pressure deviation correction signal 29 and generator output deviation correction. A diagram showing the relationship with the signal 31, FIG. 4 is a diagram showing the relationship between time and the generator output deviation value, and FIG. 5 is a diagram showing the relationship between time and the steam pressure deviation value, FIG. Is a block diagram showing a conventional example, FIG. 7 is a diagram showing the relationship between the output command 10 and the steam pressure set value 15, and FIG. 8 is a diagram showing the relationship between time and the generator output deviation value. The figure is a diagram showing the relationship between time and steam pressure deviation. In the figure, 1 is a boiler, 2 is a steam passage, 3 is a turbine, 4 is a generator, 5 is a governor valve, 6 is a pressure gauge, 7 is an output meter, 10 is an output command, 15 is a steam pressure set value, 16 is Subtractor, 17 steam pressure detection signal, 18 steam pressure deviation signal, 20 subtractor, 21 generator output signal, 22 generator output deviation signal, 23 override circuit, 26 function generator, 27 Correction coefficient, 28 is a multiplier, 29 is a steam pressure deviation correction signal, 30 is a function generator, 31
Is a generator output deviation correction signal, 32 is an adder, 33 is a corrected generator output deviation signal, and b is an allowable range.

Claims (1)

[Claims] 1. A pressure gauge 6 for detecting a pressure of steam in a steam flow path 2 for sending steam from a boiler 1 to a turbine 3 to obtain a steam pressure detection signal 17, a steam pressure detection signal 17 and an output command of the boiler 1. A subtracter 16 for obtaining a steam pressure deviation signal 18 by taking a deviation from a steam pressure set value 15 obtained based on 10, and a function generator 26 for inputting the output command 10 to obtain a correction coefficient 27.
A multiplier 28 for multiplying the steam pressure deviation signal 18 and the correction coefficient 27 to obtain a steam pressure deviation correction signal 29, and a function generator for inputting the steam pressure deviation correction signal 29 to obtain a generator output deviation correction signal 31. 30, an output meter 7 for detecting the output of the generator 4 driven by the turbine 3 to obtain a generator output signal 21, and a deviation between the generator output signal 21 and the output command 10 to obtain a generator output deviation. A subtractor 20 for obtaining the signal 22, and an adder 32 for obtaining the corrected generator output deviation signal 33 by adding the generator output deviation correction signal 31 to the generator output deviation signal 22;
When the steam pressure deviation signal 18 and the corrected generator output deviation signal 33 are input and the steam pressure deviation signal 18 is within the preset allowable range b, the corrected generator output deviation signal 33 is output to output the steam pressure deviation. An override circuit 23 is provided for controlling the governor valve 5 for outputting the steam pressure deviation signal 18 to adjust the flow rate of the steam flowing through the steam flow path 2 when the signal 18 is out of the allowable range b. Boiler governor valve control device.