JP5017019B2 - Plant optimum operation control system - Google Patents

Description

  The present invention relates to a system for optimal operation control of a plant, and more particularly to an operation control system for minimizing the operation cost of the plant.

  In general, in an optimal operation control system for a private power plant that supplies electric power and steam to the factory, the boiler output and turbine main power are set so as to minimize the operating cost according to the amount of power received from the boiler fuel and the electric power system. The amount of steam, the amount of bleed, and the generator output are determined, and optimum operation control is performed with these values as target values.

As such a plant optimum operation control system, as shown in FIG. 10, an automatic control device 100 for controlling the steam pressure / flow rate and generator output of the plant, and the automatic control device 100 and the data input unit 2 are used. From the input state quantity of the plant 10, the optimization model from the plant model storage unit 4 and its parameters, the optimum operation point calculation unit 3 calculates the optimum operation point that minimizes the operation cost of the plant 10, and automatically Some output as a set value of the control device 100 (see, for example, Patent Documents 1 and 2).
JP 2000-78749 A JP 2004-190620 A

  In the plant optimum operation control system described above, if the optimum operation point is significantly different from the current operation point, setting the optimum operation point as it is as the control target value results in a large change in the target value. There is a problem of impairing driving.

  The present invention has been made in consideration of the above-described points, and an object of the present invention is to provide a plant optimum operation control system capable of minimizing the operation cost while keeping the operation of the plant stable.

In order to achieve the above object, in the present invention,
Optimal operating point calculation means for calculating an optimal operating point that minimizes the operating cost of the power plant based on the state quantity of the power plant and the optimization model of the power plant;
Automatic control means for automatically controlling the plant according to the optimum operating point obtained by calculation of the optimum operating point calculating means;
An input unit to which an automatic control execution signal for performing an automatic control operation of the power plant is input; and a determination unit that determines whether automatic control can be turned on according to a predetermined condition when the automatic control execution signal is input; Automatic control input means having
An optimization variable selection means for selecting a part of the optimization variable of the power plant optimization target in the optimization model when performing automatic control operation by the automatic control means, and
When it is determined by the automatic control input means that automatic control input is possible, the optimum operating point calculation means obtains the optimum operating point by further using the optimization variable selected by the optimization variable selecting means, the optimal operating point is output to the automatic control means, and displaying the optimal operating point,
When it is determined by the automatic control input means that automatic control input is impossible, or when the automatic control execution signal is not input to the input unit of the automatic control input means, the optimization variable selection means optimizes the variable. a preset operating point without selecting output to the automatic control means, also, the optimum operating point determined by the optimal operating point calculating means without selecting the optimization variables by the optimization parameter selecting portion A plant optimum operation control system characterized by displaying
Is to provide.

  Since the present invention selects the variable to be optimized in the optimization model as described above, even if the optimal operating point of the plant is greatly different from the current operating point, the variable to be optimized is added little by little. Operating costs can be minimized without compromising the stable operation of the plant.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  A first embodiment of the present invention will be described based on FIG. 1 with reference to FIGS.

(Constitution)
FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. The plant optimum operation control system 100 as Example 1 includes a data input unit 2, an optimum operation point calculation unit 3, a plant model storage unit 4, an automatic control input unit 5, an optimization variable selection unit 6, and an operation point switching unit 7. The operation point setting unit 8, the automatic control device 9, the optimum operation point display unit 10, and the automatic control exclusion unit 11 are configured.

  The data input unit 2 is for inputting the state load such as the power load and steam load of the plant 20, the fuel flow rate of the boiler, the steam output, the main steam amount of the turbine generator, the ventilation amount, and the power generation amount. The state quantity is sent to the optimum operating point calculation unit 3. The plant model storage unit 4 stores an optimization model of the plant 20 and its parameters, and these models are sent to the optimum operating point calculation unit 3. The optimization model of the plant 20 will be described later.

  The automatic control input means 5 is for selecting whether or not to perform automatic control based on the operating point calculated by the optimal operating point calculation unit 3, and the signal indicating whether or not automatic control is selected is optimized. It is sent to the variable selection means 6 and the operating point switching unit 7.

  FIG. 2 shows a configuration of the automatic control input unit 5, and the automatic control input unit 5 includes an input unit 50 and a determination unit 51. The input unit 50 inputs an instruction for automatic control input, and the determination unit 51 determines whether automatic control input is possible.

  Returning to FIG. 1 again, it is assumed that the optimization variable selecting means 6 is put into automatic control by the automatic control throwing means 5. Thereby, a variable to be optimized is selected according to a predetermined rule, and the selected optimized variable is sent to the optimum operating point calculation unit 3.

  The optimum operating point calculation unit 3 is based on the plant state quantity sent from the data input unit 2, the optimization model sent from the plant model storage unit 4, and the optimization variable sent from the optimization variable selection unit 6. The operating point at which the operating cost of the plant 20 is minimized is calculated using an optimization method such as the method, and the calculated optimal operating point is sent to the operating point switching unit 7 and is also displayed by the optimal operating point display unit 10. It is displayed on the screen.

The operating point setting unit 8 manually sets the target operating point of the plant 20, and the set operating point is sent to the operating point switching unit 7. When the automatic control input means 5 performs automatic control input, the operating point switching unit 7 changes the operating point to be sent to the automatic control device 9 from the operating point set by the operating point setting unit 8 to the optimum operating point calculation unit 3. By switching to the optimum operating point calculated in step 1, switching to automatic control at the optimum operating point is performed.

The automatic control exclusion means 11 is for releasing the automatic control based on the operation point calculated by the optimum operation point calculation unit 3, and the automatic control release signal is sent to the operation point switching unit 7.

  Next, the optimization model calculated in the optimal operation point calculation part 3 is demonstrated.

  The private power plant 20 includes boilers 21 and 22, turbines 23 and 24, generators 25 and 26, steam pipes and electric buses that connect them, and an electric load 27, an intermediate-pressure steam load 28, and A low-pressure steam load 29 is supplied.

The operating point of the boiler and turbine generator that minimizes the fuel cost of the boiler, with the input / output characteristics of the boiler and the turbine generator and the supply and demand balance of electric power and steam as constraints, is an optimization model as follows: Can be calculated by solving
Objective function: C1 * F1 + C2 * F2 (Fuel cost) (1)
Restrictions:
P1 + P2 = PL (Power supply / demand balance) (2)
SH1 + SH2 = S1 + S2 (high pressure steam balance) (3)
SM1 + SM2 = SML (Medium pressure steam supply-demand balance) (4)
SL1 + SL2 = SLL (Low-pressure steam supply / demand balance) (5)
S1 = f1 (F1) (Input / output characteristics of boiler 21) (6)
S2 = f2 (F2) (Input / output characteristics of boiler 22) (7)
SH1 = g1 (P1, SM1, SL1) (input / output characteristics of turbine 23 / generator 25) (8)
SH2 = g2 (P2, SM2, SL2) (I / O characteristics of turbine 23 / generator 25) (9)
(Upper and lower limits of each variable) (10)
here,
(Optimization variable)
F1, F2: Fuel flow of boilers 21 and 22
S1, S2: Steam pressure of boilers 21 and 22
SH1, SH2: Main steam flow rate of turbines 23, 24
SM1, SM2: Extraction flow rate of medium pressure steam of turbines 23, 24
SL1, SL2: Extraction flow rate of low-pressure steam of turbines 23, 24
P1, P2: Generator output of generators 25, 26 (Parameter)
C1, C2: Fuel cost of boilers 21 and 22
f1, f2: Boiler input / output characteristic functions
g1, g2: Input / output characteristic function of turbine generator
PL, SML, SLL: Loads of electric power, medium pressure steam, and low pressure steam.

  Among these parameters, the power load PL, the medium pressure steam load SML, and the low pressure steam load SLL are sent from the data input unit 2, and the other parameters are sent from the plant model storage unit 4.

  As an optimization method, linear programming can be applied by approximating the input / output characteristic function of each device with a linear model, and nonlinear programming can also be applied to a nonlinear model.

(Function)
FIG. 3 is a flowchart illustrating an example of a processing procedure according to the first embodiment of the present invention. As shown in FIG. 3, the plant optimum operation control system 100 first determines whether or not automatic control input by the automatic control input means 5 has been performed (S201).

  When automatic control is turned on, the optimization variable selection unit 6 selects an optimization variable in the above equations (1) to (10) of the optimization model according to a predetermined procedure (S202). That is, immediately after automatic control is turned on, no variable is selected as an optimization variable, and the state quantity of each variable is used as a constraint condition as it is. At this time, the upper and lower limit constraint equation (10) of each variable may be ignored.

  Then, the optimization variable selection unit 6 selects the optimization variables in a predetermined order for each control cycle, and finally selects all the optimization variables that were selected immediately before the automatic control is input. At this time, as the selection order of the optimization variables, the current optimization variable state quantities may be selected in ascending order of difference from the optimum operating point before the automatic control is turned on. Alternatively, the optimization variable selection unit 6 may select an optimization variable by being set by an operator.

  Next, when automatic control is turned on, the operation point switching unit 7 switches the operation point to be sent to the automatic control device 9 to use the optimum operation point calculated by the optimum operation point calculation unit 3. (S203).

On the other hand, when automatic control is not input, these steps S202 and S203 are not executed. Then, the plant optimum operation control system 100 inputs the state quantity of the plant via the automatic control device 9 by the data input unit 2 and reads the data from the plant model storage unit 4 to obtain the optimum operation point calculation unit. Data to be processed in step 3 is prepared (S204).

  Based on this data, the optimum operating point calculation unit 3 performs optimization calculation on the models of the above formulas (1) to (10) (S205). The calculated optimum operating point is displayed on the screen or the like by the optimum operating point display unit 20 (S206).

Finally, the plant optimum operation control system 100 outputs an operation point to the automatic control device 9 (S207). Here, when the automatic control is turned on, the optimum operating point calculated by the optimum operating point calculating unit 3 is output to the automatic control device 9 by the operating point switching unit 8, otherwise, The operating point set by the operating point setting unit 8 is output.

FIG. 4 is a flowchart showing a processing procedure in the automatic control charging means 5 of the plant optimum operation control system 100 . As shown in FIG. 4, the automatic control input means 5 first determines whether or not an automatic control execution signal is input by the input unit 50 (S401).

  When the automatic control execution signal is input, the determination unit 51 of the automatic control input unit 5 determines whether automatic control input is possible based on a predetermined condition (S402). Examples of conditions that do not apply to automatic control include “there is an alarm signal from the plant”, “the state quantity is an abnormal value”, and “the deviation from the upper and lower limit constraints of the optimization variable”. If automatic control input is possible, the automatic control input means 5 outputs an automatic control execution signal (S403).

  Further, the automatic control exclusion means 11 determines whether or not to cancel the automatic control according to a predetermined condition, and outputs an automatic control cancellation signal to the operating point switching unit 7 when it is determined to cancel the automatic control. And prevent automatic control input from continuing. As conditions for not entering automatic control, the same conditions as the automatic control entry determination can be considered.

(effect)
According to the first embodiment, even when the optimum operating point of the plant is greatly different from the current operating point, it is possible to optimize by adding the variables to be optimized little by little, so that the stable operation of the plant is impaired. Without this, the operating cost can be minimized.

  In addition, since the automatic operation at the optimum operating point is executed only when the plant is stably operated by the automatic control input unit 5 and the automatic control exclusion unit 11, the possibility of impairing the operation stability of the plant can be reduced.

  A second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component same as Example 1, and the overlapping description is abbreviate | omitted.

(Constitution)
FIG. 5 is a block diagram showing the configuration of the plant optimum operation control system according to the second embodiment of the present invention. In the plant optimum operation control system 30 of the second embodiment, the optimization variable selection unit 6 is removed from the plant optimum operation control system 1 of the first embodiment, and a target operation point creation unit 31 is added instead of the operation point switching unit 7. Is.

  When the automatic control input means 5 performs the automatic control, the target operating point creation unit 31 and the optimal operating point calculated by the optimal operating point calculator 3 and the optimal operating point calculated by the optimal operating point calculator 3 are displayed. Then, a target operating point obtained by interpolating these is created, and the created target operating point is sent to the automatic control device 9.

(Function)
FIG. 6 is a flowchart illustrating an example of a processing procedure according to the second embodiment. As shown in FIG. 6, the plant optimum operation control system 30 first inputs the state quantity of the plant via the automatic control device 9 by the data input unit 2 and reads the data from the plant model storage unit 4. The data to be processed by the optimum operating point calculation unit 3 is prepared (S401).

  And the plant optimal operation control system 30 performs the optimization calculation with respect to the model of said Formula (1)-(9) by the optimal operation point calculation part 3 (S402). The calculated optimum operating point is displayed on the screen or the like by the optimum operating point display unit 10 (S403).

  Next, the plant optimum operation control system 30 determines whether or not automatic control is turned on (S404).

  When automatic control is turned on by the automatic control turning-on means 5, the optimum operating point calculated by the optimum operating point calculation unit 3 as a target operating point sent to the automatic control device 9 by the target operating point creation unit 31. A target operating point is created from the current operating point (S405).

FIG. 7 is a diagram illustrating a method of creating a target operating point from the optimal operating point and the current operating point. As shown in FIG. 7, if the target operating point is moved from the current operating point to the optimal operating point after 5 control cycles, for example, the target operating point is
Xt + 1 = Xt + ΔX, ΔX = (Xo-Xt) / 5 (11)
Calculated as Xo: optimal operating point, Xt: current operating point, Xt + 1: target operating point .

  When automatic control is not turned on, the operating point set by the operating point setting unit 8 is set as the target operating point.

  Finally, the plant optimum operation control system outputs an operation point to the automatic control device 9 (S406). Here, when the automatic control is turned on, the operating point created by the above equation (11) is output to the automatic control device 9, and when the automatic control is not turned on, the operating point setting unit 8 The operating point set by is output.

(effect)
According to the second embodiment, even when the optimal operating point of the plant is greatly different from the current operating point, the target operating point set in the automatic control device is gradually changed from the current operating point to the optimal operating point. Since the change can be made, the operation cost can be minimized without impairing the stable operation of the plant.

A reference example of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component same as Example 1 and Example 2, and the overlapping description is abbreviate | omitted.

(Constitution)
FIG. 8 is a block diagram showing the configuration of the third embodiment of the present invention. The plant optimum operation control system 40 according to the third embodiment includes a data input unit 2, an optimum operation point calculation unit 3, a plant model storage unit 4, an optimum operation point display unit 10, a demand prediction unit 41, a demand prediction model storage unit 42, An optimum operating point determination unit 43 and an alarm notification unit 44 are included.

  The demand prediction unit 41 predicts future power demand and steam demand using the power load and steam load data input from the data input unit 2 based on the demand prediction model stored in the demand prediction model storage unit 42. The predicted demand data is output to the optimum operating point calculation unit 3.

  The demand prediction model stored in the demand prediction model storage unit 42 includes a multiple regression model and a neural network model, but other prediction models can also be applied.

  The optimum operating point calculation unit 3 is based on the power demand prediction value and the steam demand prediction value output from the demand prediction unit 41 and the optimization model output from the plant model storage unit 4 and is an optimization method such as mathematical programming. Is used to calculate the operating point at which the operating cost of the plant is minimized, and the calculated optimal operating point is displayed on the screen or the like by the optimal operating point display unit 10.

  When the optimum operation point calculated by the optimum operation point calculation unit 3 satisfies a predetermined condition, the optimum operation point determination unit 43, for example, has no optimum solution or the optimization variable is set to the upper and lower limit values. It is determined whether or not it has been reached, and the determination result is output to the alarm notification unit 44.

When the optimum operation point determination unit 43 determines that the condition is satisfied, the alarm notification unit 44 issues an alarm.

(Function)
FIG. 9 is a flowchart illustrating an example of a processing procedure according to the reference example . As shown in FIG. 9, the plant optimum operation control system 40 first inputs the state quantity of the plant via the automatic control device 9 by the data input unit 2 and reads the data from the demand prediction model storage unit 42. Thus, data to be processed by the demand prediction unit 41 is prepared (S901).

  Then, the demand prediction unit 41 predicts future demand using a multiple regression model or a neural network model (S902).

  Next, the plant optimum operation control system 40 uses the demand predicted by the demand prediction unit 41 by the optimum operation point calculation unit 3 and the optimization model stored in the optimization model storage unit 4. The future optimum operating point is calculated (S903). The calculated optimum operating point is displayed on the screen or the like by the optimum operating point display unit 10 (S904).

  The plant optimum operation control system 40 determines whether or not the optimum operation point calculated by the optimum operation point calculation unit 3 satisfies a predetermined condition by the optimum operation point determination unit 43 (S905). If so, an alarm is issued by the alarm issuing unit 44 (S906).

(effect)
According to this reference example , the future optimum operating point of the plant can be predicted based on the demand forecast of the plant, and whether or not the predicted optimum operating point deviates from the stable operating range of the plant. Predict and inform operators. Thereby, in order to minimize the operation cost of the plant, it is possible to predict in advance whether or not stable operation can be maintained.

The block diagram which shows the structure of the plant optimal operation control system which concerns on Example 1 of this invention. The block diagram which shows the structure of the automatic control injection | throwing-in means in the plant optimal operation control system which concerns on Example 1 of this invention. The flowchart which shows the process sequence of the plant optimal operation control system which concerns on Example 1 of this invention. The flowchart which shows an example of the process sequence of the automatic control injection | throwing-in means in the plant optimal operation control system which concerns on Example 1 of this invention. The block diagram which shows the structure of the plant optimal operation control system which concerns on Example 2 of this invention. The flowchart which shows the process sequence of the plant optimal operation control system which concerns on Example 2 of this invention. The figure explaining the target operating point creation method of the plant optimal operation control system concerning Example 2 of the present invention. The block diagram which shows the structure of the plant optimal operation control system which concerns on the reference example of this invention. The flowchart which shows the process sequence of the plant optimal operation control system which concerns on the reference example of this invention. The figure which shows an example of the conventional plant optimal operation control system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Data input part 3 ... Optimal operation point calculation part 4 ... Plant model memory | storage part 5 ... Automatic control input means 6 ... Optimization variable selection part 7 ... Operation point switching part 8 ... Operation point setting part 9 ... Automatic control apparatus 10 ... Optimal operation point display section 11 ... Automatic control exclusion means 20 ... Private power plant 30, 40, 100 ... Plant optimum operation control system

Claims (8)

Optimal operating point calculation means for calculating an optimal operating point that minimizes the operating cost of the power plant based on the state quantity of the power plant and the optimization model of the power plant;
Automatic control means for automatically controlling the plant according to the optimum operating point obtained by calculation of the optimum operating point calculating means;
An input unit to which an automatic control execution signal for performing an automatic control operation of the power plant is input; and a determination unit that determines whether automatic control can be turned on according to a predetermined condition when the automatic control execution signal is input; Automatic control input means having
An optimization variable selection means for selecting a part of the optimization variable of the power plant optimization target in the optimization model when performing automatic control operation by the automatic control means, and
When it is determined by the automatic control input means that automatic control input is possible, the optimum operating point calculation means obtains the optimum operating point by further using the optimization variable selected by the optimization variable selecting means, the optimal operating point is output to the automatic control means, and displaying the optimal operating point,
When it is determined by the automatic control input means that automatic control input is impossible, or when the automatic control execution signal is not input to the input unit of the automatic control input means, the optimization variable selection means optimizes the variable. a preset operating point without selecting output to the automatic control means, also, the optimum operating point determined by the optimal operating point calculating means without selecting the optimization variables by the optimization parameter selecting portion A plant optimum operation control system characterized by displaying. When it is determined by the automatic control input means that automatic control input is possible, it has an operation point switching means for switching the operation point output to the automatic control means to the optimum operation point obtained by the optimum operation point calculation means. The plant optimum operation control system according to claim 1. If it is determined that can be automatically controlled is turned on by the automatic control dosing means, after which the automatic control is selected, and calculates the optimum operating point in a state where the optimization variables is not selected The plant optimum operation control system according to claim 1 or 2.   The plant optimization operation control system according to any one of claims 1 to 3, wherein the optimization variable selection unit selects an optimization variable selected in advance in descending order of change amount.   The plant optimum operation control system according to any one of claims 1 to 4, wherein the optimum operation point calculation means ignores the upper and lower limit constraints of the optimization variable. Optimal operating point calculation means for calculating an optimal operating point that minimizes the operating cost of the power plant based on the state quantity of the power plant and the optimization model of the power plant;
Automatic control means for automatically controlling the plant based on an optimization model according to the optimum operating point obtained by calculation of the optimum operating point calculating means;
An input unit to which an automatic control execution signal for performing an automatic control operation of the power plant is input; and a determination unit that determines whether automatic control can be turned on according to a predetermined condition when the automatic control execution signal is input; Automatic control input means having
An optimum operating point display means for displaying the optimum operating point calculated by the optimum operating point calculation means,
When it is determined by the automatic control input means that automatic control input is possible, a target operating point is obtained from the optimum operating point obtained by the optimum operating point calculating means and the current operating point, and this target operating point is determined. Outputting to the automatic control means, and further displaying the optimum operating point on the optimum operating point display means,
When it is determined by the automatic control input means that automatic control input is impossible, or when the automatic control execution signal is not input to the input section of the automatic control input means, the automatic control is performed on a preset operating point. and outputs to the means, further, the plant optimum operation control system and displaying the optimum operating point to the optimum operating point display means. The plant optimum operation control system according to claim 6 , wherein the target operation point is changed from the current operation point to the target operation point at a constant rate for each predetermined period. The plant optimum operation control system according to any one of claims 1 to 7, further comprising an automatic control canceling unit that cancels the automatic control even when the automatic control is selected by the automatic control unit. .

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