JPH11182209A - Operation control device for plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adequately and automatically adjust dynamic feedforward control signals considering an effect of interference, by modifying variation amount of the dynamic feedforward control signals so that the variation amount of the feedforward control signals act to a part of controlled objects and action to the other controlled objects is small. SOLUTION: Operation state of a plant 100 is measured by data measuring devices such as a generator output measuring instrument 111, a main steam temperature measuring instrument 122, and a main steam pressure measuring instrument 124, and is transmitted to an operation control device 300. The operation control device 300 calculates characteristic quantity based on these process data, and calculates variation amount of feedforward control signals for plural controlled objects based on the characteristic quantity. The calculated variation amount of the feedforward control signals is modified so that the variation amount of the feedforward control signals acts to a part of the controlled objects and action to the other controlled objects is small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plant operation control device. In particular, a steam generating means for exchanging the supply water by exchanging heat with a supply gas and a combustion gas generated by burning fuel, and a heat generating means for exchanging heat of the vapor evaporated by the steam generation means with the combustion gas to raise the temperature. Thermal power generation system comprising an exchanger and a steam turbine driven by the steam, and controlling a predetermined process amount to a desired value using a feedforward control signal according to a dynamic characteristic of the plant when a load of the plant changes. The present invention relates to a plant operation control device.

The present invention does not depend on the type of fuel and can be applied to waste incineration power generation as long as the plant satisfies the above configuration.

[0003]

2. Description of the Related Art In the control of a thermal power plant, fluctuations in steam temperature are suppressed mainly by feedback control and feedforward control. In particular, a thermal power plant has a large response delay, and is a control method in which feedforward control is effective. However, a control parameter that determines a control signal in this control method is conventionally manually adjusted by a plant operator while observing a change in a control amount. When the load of the plant changes, a dynamic (transient) feedforward control signal is used to compensate for the non-linearity and the response time delay of the plant. For example, the control parameters for determining the dynamic feedforward control signal for the fuel flow rate are adjusted by the operator himself based on the knowledge and experience of the operator from observation results such as the main steam temperature.

A method for adjusting a dynamic feedforward control signal is disclosed in Japanese Patent Application Laid-Open Nos. 6-222808 and 7-44205.
No. Gazette. These methods adjust a dynamic feedforward control signal based on a characteristic amount of a response waveform of a control amount of a plant.

Further, a method of modeling a characteristic of a plant and obtaining a dynamic feedforward control signal using an inverse function of the model is disclosed in IEEJ Transactions on Electronics, Vol. 116, No. 1.
0, 1996, pp 1105-1110.

[0006]

The characteristics of a thermal power plant are complicated, and the effect of changing one operation amount may affect another control amount. For example, if the main steam temperature is controlled mainly by controlling the fuel flow rate and the main steam pressure is controlled mainly by controlling the feedwater flow rate, each manipulated variable does not necessarily affect only the respective control target. Fuel flow rate also affects main steam pressure, and feedwater flow rate also affects main steam temperature.
That is, the process is often an interference system.

In this case, even if the change of the operation amount is determined independently, the desired control accuracy cannot be obtained in many cases.
None of the above-mentioned prior arts describes measures against this interference system.

An object of the present invention is to automatically adjust a dynamic feedforward control signal appropriately for a plurality of dynamic feedforward control signals serving as an interference system of a thermal power plant in consideration of the influence of mutual interference. Is to provide.

[0009]

According to the present invention, there is provided a steam temperature measuring means for measuring a temperature at one or a plurality of locations of the flow path of the generated steam, and the steam temperature at a plurality of locations measured by the steam temperature measuring means. Means for calculating a characteristic amount for the measured value of the above, means for calculating the feedforward control signal or a change amount of the control signal for a plurality of control targets based on the characteristic amount, and a method for calculating the feedforward control signal or the control signal. Decoupling means for modifying the amount of change of the feedforward control signal or the control signal so that the amount of change acts on a part of the controlled object but reduces the effect on the remaining controlled objects. It is characterized by.

[0010]

Embodiments of the present invention will be described.

FIG. 2 shows the basic configuration of a thermal power plant 100 to be used. In the boiler 150, fuel and air are supplied to a burner and burned, and supply water circulated by a water supply pump 140 is evaporated. The steam that has been further heated and turned into an overheated state is passed through a turbine control valve to the high-pressure turbine 130.
To drive the high-pressure turbine 130. The steam that has passed through the high-pressure turbine is heated again by the boiler and enters the low-pressure turbine. Electric power is generated by the generator 110 by the rotation of the high and low pressure turbines. Hereinafter, the steam at the high pressure turbine inlet is referred to as main steam, and the steam at the low pressure turbine inlet is referred to as reheat steam.

In the thermal power plant, in addition to the above components, there are also devices such as a condenser for cooling and condensing steam after driving the turbine and a combustion exhaust gas treatment device, but the description is omitted here. .

The operating state of the plant 100 is measured by data measuring devices such as a generator output measuring device 111, a main steam temperature measuring device 122, a main steam pressure measuring device 123, a reheat steam temperature measuring device 124, and the like, and an operation control device. It is transmitted to 300. The operation control device 300 grasps the operation state of the plant based on these process data, and controls the fuel flow control valve 162, the air flow control valve 161, the turbine control valve 121, and the water supply pump 140 so that the plant is in a desired state. And other devices are controlled.

In the present invention, the type of fuel such as oil or gas is not limited, but when coal is used as the fuel, the pulverizer for pulverizing the coal is controlled to adjust the fuel flow rate.

The structure of the boiler 150 will be described with reference to FIG. Inside the boiler 150, a economizer 151 which is a heat exchanger for generating steam and raising the temperature of the steam, a furnace water wall 152, an evaporator 153, a primary superheater 154, a secondary superheater 155, and a tertiary superheater 156, fourth superheater 157, primary reheater 158,
The secondary reheater 159 is arranged at the position shown in FIG.

The primary reheater and the primary superheater are separated by a partition, and a gas distribution damper 170 for adjusting the distribution ratio of the flow rate of the combustion gas flowing to each side is provided. The order of the flow of water or steam flowing through each heat exchanger is as shown in FIG.

Next, a control method of the thermal power plant 100 will be described with reference to FIG.

The operation control device 300 operates the fuel flow control valve 162, the water supply pump 140, the turbine control valve 121, etc. so as to satisfy the required load command, and the main steam temperature 202, the main steam pressure 204, the reheat The steam temperature 203 and the like are controlled. If these control amounts fluctuate significantly from the target values (set values) 512 to 514 when the load changes, equipment such as the turbine will be damaged. Therefore, it is necessary to minimize fluctuations in the control amounts. However, the thermal power plant has a large time constant of several minutes to several tens of minutes, and it is not easy to control the boiler output. In addition, the physical relationship between the operation amount and the control amount is complicated, and the occurrence of interference between control loops also causes difficulty in control.

The control method of the operation control device 300 includes an FBC (feedback control) controller that determines an operation amount based on PI (proportional / integral) calculators 537 to 540 of a control deviation, and an FFC (feedback control) based on a load command value. (Feed-forward control) controller. FFCs are roughly classified into static FFC controllers 531 to 533 and dynamic FFC controllers 534 to 536. Static FF
C determines the input amount (fuel flow rate, feed water flow rate, etc.) required to obtain the boiler output that matches the load command value 520. The dynamic FFC determines an input amount for correcting a fluid flow delay or a heat transfer delay.

Hereinafter, the boiler input amount command determined by the dynamic FFC is referred to as BIR (Boiler InputRegulation). The need for BIR and the characteristics of the plant will be described.

For example, when the load is increased, the flow rate of water supplied to the boiler is increased in order to increase the flow rate of steam supplied to the turbine. At the same time, the fuel flow rate is increased in proportion to the increase in the feedwater flow rate. However, in the steam pipe located on the upstream side (the side of the economizer 151), the heat transfer speed due to fuel combustion is lower than the flow speed of the feedwater flow. In addition, the steam enthalpy drops transiently.

On the other hand, on the downstream side (reheaters 158 and 159 side)
The enthalpy of the steam pipe does not decrease immediately after the increase of the feedwater flow rate, but rather increases due to the increase of the combustion gas temperature due to the increase of the fuel flow rate.

Therefore, when the fuel BIR and the gas distribution damper BIR are not provided (in the case of only the static FFC), the response of the steam temperature at the outlet of each heat exchanger at the time of increasing the load is not uniform depending on the load change condition. It shows a characteristic in which it rises and then falls, and settles to a target value after the load change ends.

Therefore, in order to compensate for the transient decrease in the steam enthalpy generated on the upstream side, it is necessary to transiently increase the fuel flow rate and increase the combustion gas temperature. The control signal for determining this transiently required fuel flow is the fuel BIR
It is.

The gas distribution damper 170 plays a role to keep the ratio of the amount of heat absorbed between the main steam side and the reheat steam side at an appropriate level.
It is. The gas distribution damper distributes the combustion gas from the reheater located downstream of the steam pipe to the evaporator located upstream of the steam pipe and the primary superheater 154 when the load is increased. Correct the enthalpy deviation between the two.
In order to correct this deviation, a control signal for determining the distribution ratio of the combustion gas flow rate is a gas distribution damper BIR.

FIG. 6 shows the relationship between the static FFC signal and the dynamic FFC signal (fuel BIR) for the fuel when the load increases.
When the load command changes on the ramp, the static FFC signal indicates an amount of fuel increase corresponding to the load change. On the other hand, the fuel BIR instructs an increase in the fuel according to the dynamic characteristics of the plant in a time zone after the load change starts and after the load change ends.

The control command for the final fuel flow rate is the sum of the static FFC signal and the fuel BIR.

In this embodiment, for the purpose of suppressing fluctuations in the main steam temperature and the reheat steam temperature, a BIR (a fuel BIR and a gas distribution damper B, respectively) for controlling a fuel flow rate and a gas distribution damper are used.
BIR automatic adjustment device 40 for automatically adjusting the
0 is provided. FIG. 1 shows a basic configuration of the present invention.

The thermal power plant is roughly divided into a plant body 100 composed of devices such as a boiler and a turbine, and an operation control device 300 for controlling them. Plant body 10
In order to control 0, it is necessary to first grasp the state of the plant.

For this purpose, various process data 210 such as steam temperature and steam pressure are stored in the process data measuring device 20.
It is measured using 0. Process data measurement device 20
0 sends the necessary information 220 of the measured data to the operation control device 300 and also stores the data in its own storage device.

The operation control device 300, after grasping the state of the plant, creates a control signal 310 of the plant component equipment according to the operation conditions such as a load change and the like, and
Control 0.

The control system uses both feedback control and feedforward control.

The feedforward control includes a control (static feedforward control, hereinafter referred to as BID) based on a static characteristic corresponding to a change in load of the plant and a dynamic signal for responding to a response time delay or non-linear characteristic of the plant. Control (dynamic feedforward control: the BID).

The BID signal is an amount determined by the static characteristics of the plant, and can be determined relatively easily. On the other hand, since the BIR signal is related to the dynamic characteristics of the plant and varies depending on load change conditions such as a load change rate and a load change width, it is difficult to appropriately determine the BIR signal.

Conventionally, since the coordinator or the operator adjusts the BIR signal by trial and error while monitoring the process data, the quality of the BIR signal depends on the knowledge and experience of the operator. Since the quality of the BIR signal greatly affects the main control amount of the plant, it is a very important control signal in consideration of the influence of damage to the components of the plant.

It is an object of the present invention to provide a method for automating and optimizing the adjustment of a BIR signal.

The operation control device 300 includes the plant control circuit 5
00 and a BIR automatic adjustment device 400 which is a feature of the present invention. An algorithm and control parameters for controlling the plant are programmed in the plant control circuit 500 (see FIG. 5).

An outline of the function of the BIR automatic adjustment device 400 will be described.

The process data required by the process data measuring device 200 (the main steam temperature 201 and the reheat steam temperature 202 in this embodiment) and the target values corresponding to the respective process amounts programmed in advance from the target value calculation circuit 510. 511 to 512 are received. The data conversion function 410 processes the data to extract the characteristics of each process data.

Next, the feature amount of each process data is extracted by the feature amount extracting function 420.

In the BIR correction function 430, the feature quantity extracted by the feature quantity extraction function 420 is calculated by the fuzzy inference function 431 as the antecedent part of the fuzzy rule 432, and the BIR correction coefficient of the consequent part is calculated.

In the BIR signal update function 433, the current B
The IR signal is multiplied by the BIR correction coefficient calculated by the BIR correction function 430 to generate an updated BIR signal. The decoupling function 434 receives the updated BIR signal as an input, reduces interference with a plurality of control amounts, and calculates a final updated value of the BIR signal. The BIR signal update value is stored in the plant control circuit 50.
It is sent to 0 and becomes the BIR for the next operation.

At the same time, the updated value of the BIR signal is
The result is output to the display screen so that the operator can confirm the change result. At this time, whether to replace the BIR generation circuit of the plant control circuit 500 with the updated value may be determined by the operator's judgment.

Next, the function of the BIR automatic adjustment device 400 will be specifically described.

In the data conversion function 410, the main steam temperature 2
01, receives the time series data of the reheat steam temperature 202,
The deviation from each of the target values 511 to 512 is calculated for each time.

In the feature value extraction function 420, the feature value of each data is obtained from the deviation value calculated for each time. Features are
The time zone during the load change (τ _{0 to} τ ₁ ), the time zone from the end of the load change to the steam temperature setting (τ _{1 to} τ ₂ ), and the entire time zone (load change start to steam temperature setting: τ ₀ to τ ₂ ) (see FIG. 7).

In this example, the characteristic amount is determined by calculating the time average value (T) of the steam temperature deviation in each time zone of the main steam temperature and the reheat steam temperature.
_MST , T _MSF , T _MSB ) and (T _RST , T _RSF , T _RSB ).

Here, τ ₀ is the load change start time,
τ ₁ and τ ₂ are defined by the following equations as functions of the load change time τ _MWD .

[0049]

Τ ₁ = τ ₀ + k ₁ × τ _MWD (1)

[0050]

Τ ₂ = τ ₀ + k ₂ × τ _MWD (2) where k ₁ and k ₂ are constants.

In this embodiment, k ₁ and k ₂ are constants, but the response characteristic of the steam temperature varies not only with the load change time τ _MWD but also with the load change rate, load change width, load band, and the like. , K ₁ and k ₂ may be defined as these functions. In addition, as the feature amount, a maximum value of the deviation or a time until the maximum deviation occurs may be adopted.
It may be a combination with the feature amount used in this example.

Next, the function of the BIR correction function 430 will be specifically described. The BIR correction function 430 corrects the waveform of the BIR signal based on the feature calculated by the feature extraction function 420.

Although the BIR signal waveform is not always a perfect square as shown in FIG. 7, basically the time τ _aff , τ from the start of the input of the BIR signal until the BIR change rate (gradient) becomes relatively gentle. _apd (hereinafter referred to as a BIR rise time), times τ _bff and τ _bpd until the absolute value of the BIR signal begins to decrease to zero (hereinafter referred to as a BIR extraction time), and a total amount S _{ff of the} BIR signal. S _pd (the area of the BIR waveform) is an important factor.

The correction coefficients for these three parameters are obtained by fuzzy inference to correct the BIR signal. For example, the change of the parameter related to the fuel BIR can be performed by using equations (6) to
(8). Here, C _τaff , C _τbff , C _Sff
Are BIR start-up time, BIR extraction time, BI
Correction coefficients obtained by fuzzy inference for the area of the R waveform, and τ ′ _aff , τ ′ _bff , and S ′ _ff are values after correction of each parameter.

[0055]

Τ ′ _aff = C _τaff τ _aff (3)

[0056]

Τ ′ _bff = C _τbff τ _bff (4)

[0057]

S ′ _ff = C _Sff S _ff (5) The gas distribution damper BIR can be similarly modified.

Next, a method of obtaining a parameter correction coefficient by fuzzy inference will be described.

FIG. 8 shows a membership function for adjusting the fuel BIR with respect to the antecedent part (feature amount) and the consequent part (parameter correction coefficient) of the fuzzy inference. The inference rule table is configured as shown in FIG. NB (negatively large), ZE (suitability:
Zero), PB (positively large) and SM (decrease), M
F (no change) and BG (increase) fuzzy variables are assigned.

In the case of fuel BIR adjustment, as shown in FIG. 8, the horizontal axis of the membership function of the evaluation index is
_{These are} the feature amounts T _MST , T _MSF , and T _MSB . T _MST , T _MSF , T
_With respect to the _MSB value, the degree of influence (0 to 1) on the vertical axis is obtained from the membership function of the evaluation index.

On the other hand, in the membership function of the correction coefficient, the horizontal axis represents the parameter correction coefficients C _Sff , C _τaff , and C _τbff , and the vertical axis represents the degree of influence.

The degree of influence on T _MST , T _MSF , and T _MSB of the antecedent part is determined for each fuzzy rule number shown in FIG. 9, and the minimum degree of influence is determined. For the fuzzy variables (SM, ME, BG) indicated in the consequent at that time, the area from the base of the membership function triangle to the value of the minimum influence degree of the antecedent and the position of the center of gravity are calculated. This is calculated for all rule numbers, and the position of the center of gravity obtained by superimposing all areas is set as the value of the correction coefficient. The correction coefficient for the gas distribution damper BIR can be calculated in a similar manner.

In the fuzzy inference of this example, the method of Mamdani is used, and defuzzification is performed.
Used the composite centroid method, but the present invention is not limited to this method. The use of fuzzy inference is not an essential condition, and the relationship between the comprehensive evaluation index and the parameter correction coefficient may be converted into a function or a table in advance.

The specific method of correcting the BIR waveform is defined as fuel BIR
Will be described as an example (see FIG. 10). First, from the BIR waveform ABCD before correction, the BIR rise time and the BIR extraction time are corrected by the equations (3) and (4), and the waveform AB "CD"
Get. Next, the corrected area is calculated by the equation (5), and a waveform AB'C'D "equal to the corrected area is obtained.

As described above, the fuel BIR signal is corrected based on the characteristic amount of the main steam temperature, and the gas distribution damper BIR signal is corrected based on the characteristic amount of the reheated steam temperature.

However, when the fuel flow rate, that is, the fuel BIR is changed, the temperature of the combustion gas changes, and this affects not only the main steam temperature but also the reheat steam temperature. Further, when the gas distribution damper opening degree, that is, the gas distribution damper BIR is changed, the gas flow distribution between the primary reheater and the primary superheater changes, so that the reheat steam temperature changes. At the same time, the temperature of the steam at the outlet of the primary superheater also changes, which eventually affects the temperature of the main steam located downstream thereof.

Therefore, even if the corrected BIR is used, the other control amount is affected, and as a result, the desired effect may not be obtained.

Therefore, in the present invention, the decoupling function 434 is used.
, The fluctuation of both control amounts is suppressed. FIG.
The decoupling function 434 will be described with reference to FIG.

The decoupling function 434 is connected to the plant control circuit 5
From 00, the static FFC signals 501 and 502 for the fuel and gas distribution dampers and the BIR signal correction values 433a and 433b output from the BIR signal update function 433 are input, and the static FFCs for both the fuel and gas distribution dampers are respectively input. The correction values of the signal and the BIR signal are added.

The added control signals 434a and 434b are corrected by the transfer functions set in the cross controllers C ₁ and C ₂ to obtain final BIR updated values 436 and 437.
Becomes The BIR update values 436 and 437 are displayed on the display screen 600.
And output to the plant control circuit 500 to become the next BIR signal.

In FIG. 11, the static FFC signals 501, 50
2 and the BIR signals 433a and 433b are added and input to the decoupling function 434.
Only 33b may be input.

The decoupling function 434 includes a characteristic model 4 simulating the relationship between the fuel flow rate and the opening degree of the gas distribution damper, which are the manipulated variables, and the main steam temperature and the reheat steam temperature, which are the control variables.
35 is provided.

When satisfying the relations of equations (6) and (7),
The reheat steam temperature is not affected by the control signal 434a for fuel flow, and the main steam temperature is not affected by the control signal 434b for the gas distribution damper. That is, non-interference is possible.

[0074]

G ₁₁ C ₂ + g ₁₂ = 0 (6)

[0075]

G ₂₂ C ₁ + g ₂₁ = 0 (7) Transfer functions g ₁₁ , g ₁₂ , g ₂₁ , and g ₂₂ of the characteristic model 435 are obtained, and the relations of the equations (6) and (7) are satisfied. Thus, the cross controllers C ₁ and C ₂ are determined.

The transfer functions g ₁₁ , g ₁₂ ,
g ₂₁ and g ₂₂ can be obtained by a step response method or a frequency response method. In this example, the transfer function of the characteristic model 435 is determined by the step response method.

In general, the response characteristic of a plant is expressed as “first order delay +
In many cases, it can be approximated by "dead time". The approximate model (transfer function) at that time is expressed by the following equation.

[0078]

(Equation 8)

Here, L is a dead time, K is a gain, T is a time constant, and s is a Laplace operator. g ₁₁ , g ₁₂ ,
g ₂₁ and g ₂₂ are approximated by equation (8), and L, K, and T are obtained for each. The step response method will be described with reference to FIG.

[0080] For example, when determining the g _11, determine the constants a fuel flow from the response waveform of the main steam temperature when changing step. The procedure is as follows.

(1) Find a tangent BD at the inflection point A of the step response waveform. Point B is the intersection of the tangent and the time axis.

(2) The distance OB between the origin O and the point B is defined as dead time L. It is assumed that the points after the point B represent the step response waveform of the first-order delay transfer function.

(3) Let K be the steady value of the response waveform and K (1
−e ⁻¹ ) = 0.63K is a point C. Let BC be the time constant T.

The step response waveform may be a test result of an actual plant performed at the time of test operation or the like, or may be a step response test result by a plant simulator.

G ₁₂ , g ₂₁ , and g ₂₂ can be similarly obtained. If the characteristic model 435 can completely simulate plant characteristics, it is possible to completely eliminate interference by the cross controllers C ₁ and C ₂ satisfying the equations (6) and (7). However, since the characteristic model 435 is generally an approximate model and cannot completely simulate plant characteristics, the influence of mutual interference can be considerably reduced.

In this example, the transfer function in the characteristic model 435 is approximated by “first order delay + dead time”, and the model is identified by the step response method. However, the present invention is limited to this approximation method. is not.

The characteristic model 435 and the cross controller C
_It is not necessary to set ₁ and C _{2 each time} the BIR signal is adjusted, and may be set at the time of a trial run of the plant. However, if the characteristics of the plant change over time, it is necessary to review the settings at the time of periodic inspection and the like. FIG. 13 shows an example of a man-machine interface for setting the transfer function of the characteristic model 435.

[0088] For example, in the case of the parameter setting of the transfer function g _11, the transfer function g ₁₁ to set on the screen specified by the mouse. In the upper half of the main window, the specified transfer function g
₁₁ input and output (in this case, the fuel flow rate and the main steam temperature) waveform of the step response test corresponding to relationship is graphically displayed.

Next, when model selection is selected from the menu bar at the bottom of the screen, a model selection sub-window is displayed. In the model, the “first-order delay” model, the “first-order delay + dead time” model, and the like used in this example are registered, and a model that can accurately simulate the waveform of the step response test is selected. In this example, since the “first-order delay + dead time” model is selected, equation (8) is displayed on the main window,
Input the parameters K, T, L. After inputting the parameters, click the "Graph Display" button to display the model (in this case, "1st delay + dead time") in the graph in the upper half of the screen.
Model) is overwritten.

The validity of the model can be confirmed by comparing the step response test waveform with the output waveform of the model.
It is also possible to modify model parameters.

As described above, according to the present invention, the fuel BIR
In the case of an interference system that controls the main steam temperature and the reheat steam temperature using the gas and the gas distribution damper BIR as manipulated variables, the influence of mutual interference can be reduced, and effective BIR signal adjustment can be performed for a plurality of control targets. It is possible.

Further, the BIR signal can be appropriately adjusted regardless of the experience of the operator. In addition, automatically BIR
Since the signal can be adjusted and the influence of mutual interference is small, the adjustment period can be expected to be further shortened.

Further, by displaying the adjustment result according to the present invention on a CRT screen or the like, it can be used as guidance for an operator and can also be used for driving training. FIG. 14 shows a display example on the CRT screen.

In the upper half of the screen, the load command and the trend of the main steam temperature and the reheat steam temperature to be controlled are graphically displayed. In the lower half of the screen, the current value and the updated value of the fuel BIR and the gas distribution damper BIR (output of the decoupling function 434)
Is displayed. The validity of the updated value can be confirmed while referring to the control amount response waveform at the top.

In this embodiment, the operation amount (fuel BIR and gas distribution damper BIR) and the control amount (main steam temperature and reheat steam temperature) are both two types. The invention is applicable. An example in which the amount of operation and the amount of control are each three will be described with reference to FIG.

In FIG. 15, the operation amounts are u ₁ , u ₂ , and u ₃ , and the control amounts are y ₁ , y ₂ , and y ₃ . Characteristic model 435
They are interfering model to another, it simulates the respective relationships by a transfer function h ₁ to h _6. In this case, the cross-controller for non-interference is D ₁ to D _6. The relationship between the manipulated variables u ₁ , u ₂ , u ₃ and the controlled variables y ₁ , y ₂ , y ₃ is given by the following equation.
(9) to (14).

[0097]

[Equation 9] _{p 1 = u 1 + u 2} D 2 + u 3 D 1 ... (9)

[0098]

P ₂ = u ₁ D ₃ + u ₂ + u ₃ D ₄ (10)

[0099]

P ₃ = u ₁ D ₆ + u ₂ D ₅ + u ₃ (11)

[0100]

Y ₁ = p ₁ + p ₂ h ₂ + p ₃ h ₁ (12)

[0101]

Y ₂ = p ₁ h ₃ + p ₂ + p ₃ h ₄ (13)

[0102]

Equation 14] _{y 3 = p 1 h 6 +} p 2 h 5 + p 3 ... (14) u 1 does not affect the y ₂ and y _3, and u ₂ is not affected to y ₁ and y _3, and u _{In order that 3} does not affect y ₁ and y ₂ ,
Equation (9) to (11) organized for u _1, u _2, u ₃ is substituted into Equation (12) to (14), equation (12) to (14) respectively for u ₂ and u _3, u _It is sufficient that the coefficients of ₁ and u ₃ , u ₁ and u ₂ become zero. That is, equations (15) to (20)
It can be seen that it is only necessary to satisfy.

[0103]

D ₂ + h ₂ + D ₅ h ₁ = 0 (15)

[0104]

D ₁ + D ₄ h ₂ + h ₁ = 0 (16)

[0105]

H ₃ + D ₃ + D ₆ h ₄ = 0 (17)

[0106]

D ₁ h ₃ + D ₄ + h ₄ = 0 (18)

[0107]

[Equation 19] h ₆ + D ₃ h ₅ + D ₆ = 0 (19)

[0108]

D ₂ h ₆ + h ₅ + D ₅ = 0 (20) Therefore, the cross controllers D _{1 to} D ₆ may be determined so as to satisfy the equations (15) to (20).

As described above, when it is not necessary to make all the combinations of the operation amount and the control amount non-interfering, the coefficient corresponding to the relationship between the operation amount u _i to be made non-interfering and the control amount y _i is calculated. it may be determined cross controller D _i as zero.

In the same way, it is possible to deal with the case where the number of operation amounts and control amounts is increased. Equations (6) and (7) described above
Can be derived in the same way.

In the present embodiment, the main steam temperature and the reheat steam temperature are used as the control variables. However, the target may be a steam pressure other than the steam temperature, for example, the steam pressure. May be used.

Although the embodiment of the present invention has been described using a thermal power plant as an example, the present invention is also applicable to a waste power plant that incinerates waste as fuel.

[0113]

According to the present invention, even in an interference system that controls the main steam temperature and the reheat steam temperature by using the fuel BIR and the gas distribution damper BIR as the manipulated variables, a representative system that reflects the influence of both manipulated variables. Even if the BIR signal is corrected based on the feature value extracted from the simple process data, adjustment with high control accuracy is possible by the decoupling function.

Therefore, it is possible to control the control variables such as the main steam temperature and the reheat steam temperature with a small deviation from the target value.

Further, according to the present invention, it is possible to appropriately adjust the BIR signal without depending on the experience of the operator, and it is expected that the adjustment period can be shortened. Furthermore, displaying the BIR adjustment result according to the present invention can be utilized for education and training for operators.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a thermal power plant according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration example of a thermal power plant.

FIG. 3 is a diagram illustrating an example of an arrangement of heat exchangers in a boiler of a thermal power plant.

FIG. 4 is a diagram showing an example of the flow of steam and the order of heat exchangers in a thermal power plant.

FIG. 5 is a diagram illustrating a basic system example of a control circuit of a thermal power plant.

FIG. 6 is a characteristic diagram illustrating an example of a control signal of a thermal power plant.

FIG. 7 is a characteristic diagram illustrating a feature amount of a steam temperature and a BIR signal parameter according to the embodiment of the present invention.

FIG. 8 is a characteristic diagram showing a membership function in fuzzy inference according to the embodiment of the present invention.

FIG. 9 is a diagram showing an example of a fuel BIR adjustment fuzzy rule according to the embodiment of the present invention.

FIG. 10 is a characteristic diagram illustrating a method for correcting a BIR signal according to an embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of a decoupling function according to the embodiment of the present invention.

FIG. 12 is a characteristic diagram illustrating a step response method.

FIG. 13 is a diagram illustrating a setting example of a characteristic model according to the embodiment of the present invention.

FIG. 14 is a diagram illustrating a display example of a BIR signal update value according to the embodiment of the present invention.

FIG. 15 is a diagram illustrating a configuration of a decoupling function in a case where three operation amounts and control amounts are used.

[Explanation of symbols]

100: thermal power plant, 200: process data measuring device, 201: primary superheater outlet steam temperature data, 20
2: Main steam temperature data, 203: Reheat steam temperature data,
210: various process data, 300: operation control device,
310: control signal, 400: BIR automatic adjustment function, 41
0: Data conversion function, 420: Feature extraction function, 430
... BIR correction function, 431 ... Fuzzy inference function, 432
... Fuzzy rules, 433 ... BIR signal update function, 43
4: decoupling function; 435: characteristic model; 500: plant control circuit; 510: target value calculation circuit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Sato 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Eiji Toyama 4-6-6 Kanda Surugadai, Chiyoda-ku, Tokyo Address Hitachi, Ltd. (72) Inventor Toru Kimura 5-2-1, Omikacho, Hitachi City, Ibaraki Prefecture Omika Plant, Hitachi, Ltd. (72) Satoru Shimizu 5-2-2, Omikacho, Hitachi City, Ibaraki Prefecture No. 1 Inside Omika Plant of Hitachi, Ltd.

Claims (4)

[Claims] 1. A steam generating means for exchanging heat between a supply gas and a combustion gas generated by burning fuel to evaporate the supply water, and heat-exchanging the vapor evaporated by the vapor generation means with the combustion gas to raise the temperature. A superheater for heating, a first steam turbine driven by the superheated steam, a reheater for exchanging heat of the steam whose temperature has been reduced by driving the steam turbine with the combustion gas and raising the temperature again, A second steam turbine driven by steam after passing through a reheater, a fuel supply unit to the steam generation unit, and the combustion gas in contact with at least one of the superheater and at least one of the reheater A thermal power plant comprising a combustion gas flow rate adjusting means for changing the flow rate of the plant, and controlling a predetermined process amount to a desired value using a feedforward control signal according to a dynamic characteristic of the plant when the load of the plant changes. No luck In the control device, a plurality of steam temperature measuring means for measuring the steam temperature at the location of the inlet or outlet of the superheater and reheater or the first and second,
Steam temperature measuring means at the position of the inlet of the steam turbine of the above, the steam temperature of the superheater or reheater or the steam temperature of the inlet of the first and second steam turbine measured by the steam temperature measuring means Means for calculating a characteristic amount, means for calculating the feedforward control signal or the amount of change in the control signal for each of the fuel supply unit and the combustion gas flow rate adjusting unit to be controlled based on the characteristic amount, Decoupling means for modifying the feedforward control signal or the control signal change amount such that the feedforward control signal or the change amount of the control signal acts on one of the control objects but reduces the effect on the other. And an operation control device for a plant, comprising: 2. A steam generating means for exchanging heat between a supply gas and a combustion gas generated by burning fuel to evaporate the supply water, and heat-exchanging the vapor evaporated by the steam generation means with the combustion gas to raise the temperature. A superheater for heating, a first steam turbine driven by the superheated steam, a reheater for exchanging heat of the steam whose temperature has been reduced by driving the steam turbine with the combustion gas and raising the temperature again, A second steam turbine driven by steam after passing through a reheater, a fuel supply unit to the steam generation unit, and the combustion gas in contact with at least one of the superheater and at least one of the reheater A power plant for controlling a predetermined process amount to a desired value by using a feedforward control signal according to a dynamic characteristic of the plant when a load of the plant changes. No luck In the control device, a plurality of steam temperature measuring means for measuring the steam temperature at the location of the inlet or outlet of the superheater and reheater or the first and second,
Steam temperature measuring means at the position of the inlet of the steam turbine of the above, the steam temperature of the superheater or reheater or the steam temperature of the inlet of the first and second steam turbine measured by the steam temperature measuring means Means for calculating a characteristic amount, means for calculating the feedforward control signal or the amount of change in the control signal for each of the fuel supply unit and the combustion gas flow rate adjusting unit to be controlled based on the characteristic amount, Decoupling means for modifying the feedforward control signal or the control signal change amount such that the feedforward control signal or the change amount of the control signal acts on one of the control objects but reduces the effect on the other. And a means for displaying the corrected feedforward control signal or the change amount of the control signal output by the decoupling means. When operation control unit of the plant, characterized by comprising. 3. A steam generating means for exchanging heat with a supply gas and a combustion gas generated by burning fuel to evaporate the supply water, and heat-exchanging the vapor evaporated by the steam generation means with the combustion gas to raise the temperature. A heat exchanger to be heated, and a steam turbine driven by the steam, wherein a predetermined process amount is controlled to a desired value by using a feedforward control signal according to a dynamic characteristic of the plant when a load of the plant changes. The operation control device for a thermal power plant, comprising: a steam temperature measuring means for measuring a temperature at one or a plurality of locations of the flow path of the generated steam, and a measured value of the steam temperature at a plurality of locations measured by the steam temperature measuring means. Means for calculating a characteristic amount of the feedforward control signal, means for calculating the feedforward control signal or a change amount of the control signal for a plurality of control targets based on the characteristic amount, Non-interference that modifies the amount of change of the feedforward control signal or control signal so that the forward control signal or the amount of change of the control signal respectively acts on a part of the controlled object, but reduces the effect on the remaining controlled objects. A plant operation control device comprising: 4. A steam generating means for exchanging heat with a supply water by exchanging heat with a combustion gas generated by burning fuel, and a heat exchange between the vapor evaporated by the steam generation means and the combustion gas to ascend. A heat exchanger to be heated, and a steam turbine driven by the steam, wherein a predetermined process amount is controlled to a desired value by using a feedforward control signal according to a dynamic characteristic of the plant when a load of the plant changes. The operation control device for a thermal power plant, comprising: a steam temperature measuring means for measuring a temperature at one or a plurality of locations of the flow path of the generated steam, and a measured value of the steam temperature at a plurality of locations measured by the steam temperature measuring means. Means for calculating a characteristic amount of the feedforward control signal, means for calculating the feedforward control signal or a change amount of the control signal for a plurality of control targets based on the characteristic amount, Non-interference that modifies the amount of change of the feedforward control signal or control signal so that the forward control signal or the amount of change of the control signal respectively acts on a part of the controlled object, but reduces the effect on the remaining controlled objects. A plant operation control device, comprising: a conversion unit; and a unit that displays a corrected feedforward control signal output by the decoupling unit or a change amount of the control signal.