KR100757679B1 - Integrated control system for the dearator process of combined cycle thermal plant and method therefor - Google Patents

Abstract

An integrated control system for a deaerator process of a combined thermal power plant and a method for the same are provided to adjust all kinds of factors and simplify the tuning of a control system by realizing integrated control. An integrated control system for a deaerator process of a combined thermal power plant includes a deaerator process unit(1), low-ranking control devices(5), a DB handling device(70), a monitor control device(80), and an integrated high-ranking control handling device(100). The low-ranking control devices detect a controlled variable having the water level, the flux, and the pressure of each storage tank of the deaerator process unit to control an operation of the corresponding storage tank. The DB handling device collects all kinds of the controlled variables from the low-ranking control devices to save the controlled variables. The integrated high-ranking control handling device transmits a manipulated variable to the low-ranking control devices through The DB handling device. The monitor control device manages and controls various processes of a deaerator and selects low-ranking control or integrated high-ranking control which is as an operation mode of the deaerator process unit by collecting data saved and collected in the DB handling device.

Description

INTEGRATED CONTROL SYSTEM FOR THE DEARATOR PROCESS OF COMBINED CYCLE THERMAL PLANT AND METHOD THEREFOR}

1 is a schematic system diagram showing a flow rate and control of a plurality of storage tanks in a degasser process of a general combined cycle power plant.

2 is a view showing the concept of integrated control in the degasser process of the combined cycle power plant according to the present invention.

3 is a diagram showing the detailed configuration of the integrated upper control processing apparatus associated with the lower control apparatus according to an embodiment of the present invention.

4 is a diagram illustrating a model prediction control algorithm of a model prediction control unit according to an exemplary embodiment of the present invention.

5 is an output disturbance model showing the definition of the model of the model prediction control unit according to the present invention.

6 is a flowchart showing the operation of the integrated upper control processing apparatus according to the present invention.

7 is a flowchart illustrating a process model recognition process for collecting configuration definition information according to the present invention.

* Explanation of symbols for the main parts of the drawings

1: deaerator process part 5: sub-control devices

10: condenser 20: first sub-control device

30: low pressure heater 40: second sub-control device

50: deaerator 60: third sub-control device

70: DB processing device 80: supervisory control device

90: distributed control system (DCS) 100: integrated upper control processing unit (MPC)

110: DCS interface 120: configuration definition

130: system model unit 140: system recognition unit

150: model prediction control unit 151: system super mechanical part

153: model state upgrade unit 155: model predictive calculation unit

157: optimum operating variable calculation unit LT: water level sensor

LC: level controller FL: flow sensor

FC: flow controller PT: pressure sensor

The present invention relates to a control system for a degassing process of a combined cycle power plant, and in particular, a multivariate model predictive control system is operated by a deaerator, a condenser, and a low pressure heater. The present invention relates to an integrated control system and a method for a degassing process of a combined cycle power plant that can obtain a superior control performance than a conventional control method in operating a degassing process control system according to the deaerator condensation circulation process.

Combined cycle power generation uses fuels such as natural gas or diesel to turn the gas turbine first, and heats the exhaust gas from the gas turbine back to the boiler to produce steam, which in turn generates the steam turbine. Combined cycle power generation generates power twice, which has the advantage of 10% higher thermal efficiency, less pollution, and shorter operation time.

In addition, the combined cycle power generator generates electricity by turning a turbine-generator using steam obtained by burning fuel, and heats the heating water using steam that passes through the turbine. It can also be used.

FIG. 1 is a schematic system diagram illustrating a flow rate and control of a plurality of storage tanks in a degassing process of a general combined cycle power plant. The storage tank includes a condenser (10) and a low pressure heater (LP heater). And a deaerator 50.

The condenser 10 is configured to receive steam discharged from the turbine, convert the condensate into a condensate through a predetermined cooling process, and then deliver the generated condensate to the degasser 50.

The low pressure heater 30 is configured to receive some steam discharged from the turbine, perform heat exchange with hot water supplied to district heating, and deliver heat exchanged condensed water to the degasser 50.

The degasser 50 is configured to receive and store the condensed water supplied from the condenser 10 and the low pressure heater 30 and to remove impurities contained in the stored condensed water and to send it to the boiler side.

In general, in the combined cycle process, the level control of each of the storage tanks 10, 30, and 50 is a very important control process in the control of the boiler and the turbine.

However, in this process, the size of each storage tank and the distance between the control valve is far, and the interference between the water level control of each storage tank by the flow rate output between the storage tanks is difficult to implement efficient control performance.

In such a process, the conventional control method has to implement each control loop independently by using a cascade connection method by PID (Proportional plus Integral plus Derivative) control. That is, the level control of the condenser 10 is individually controlled by the first sub-control device 20 including the level sensor 21, the level controller 22, the flow rate sensor 23, and the flow rate controller 24, and the low pressure. The water level control of the heater 30 is individually controlled by the second sub control device 40 including the water level sensor 41, the water level controller 42, the flow rate sensor 43, and the flow rate controller 44. The level control of 50 is individually controlled by a third sub-control device 60 including a level sensor 61, a level controller 62 and a flow rate sensor 63.

Each of the lower control devices 20, 40, and 60 includes a water level detection sensor LT, a water level controller LC, a flow rate detection sensor FT, and a flow rate controller FC. , FT and FC are cascaded to form a control loop. In addition, the flow controller FC or the water level controller LC controls the flow rate of the flow control valve to individually control the flow rate supplied to and discharged from the storage tank.

In addition, if it is difficult to control the required level of the deaerator 50 due to the combined flow rate of the low pressure heater 30 and the condenser 10, the replenishment valve 67 is controlled to additionally supply the replenishment water or discharge the outlet. The valve 68 is used to remove the excess flow rate to the degasser.

In this case, the three sub-controllers do not consider the dependencies in each sub-controller itself in order to control the level of the three storage tanks, but each interlock function or additional function is added to compensate or operate. Unnecessary operation occurs accordingly. For example, degassing may result in excessive replenishment water or drainage operations. Therefore, automatic and rapid response to load fluctuations or disturbances is not easy and complicated. In particular, the low-pressure heater level is sensitive to changes in the flow of steam, making it an important monitoring point for operators.

Therefore, in the related art, the size and process characteristics of each storage tank of the deaerator, the condenser, and the low pressure heater are different, and the mutual interference is large due to the difference. In order to cope with this, various countermeasures and interrupts must be used.

In addition, by using a plurality of storage tanks independent control method, it is not possible to cope with each other's dependent effects in one controller, and it is difficult to respond quickly to load fluctuations, and the operator always changes the level of water in each storage tank. Since it had to be monitored, it was difficult to operate due to sensitive level fluctuations.

The purpose of the present invention is to provide three storage tanks associated with the deaerator process by applying the multivariate model predictive control method in the combined operation of the deaerator, condenser, low pressure heater of the deaerator process in the combined cycle power plant The present invention provides an integrated control system and method for the deaeration process of a combined cycle power plant that can more easily and efficiently control the water level upper and lower limits of a deaerator, a condenser, and a low pressure heater.

Another object of the present invention is to perform modeling and control offline and online for the integrated control of the degassing process in the combined cycle power generation, and for this purpose degassing apparatus of the combined cycle power plant to control in conjunction with the existing sub-controller in a separate system To provide an integrated control system and method for the process.

Another object of the present invention is to implement the integrated control in the degassing process of the combined cycle power generation, the operator who operates it can tune and operate the integrated high level control processor more effectively, and the integrated high level control processing in the lower control device. Provides integrated control system and method for degassing process of combined cycle power plant that can give the function of manually or automatically mode by detecting abnormal state of integrated upper control processing device when operating in conjunction with device There is.

Technical means of the present invention for achieving the above object is a system for controlling the degassing process of the degassing process unit including a storage tank such as a condenser, low pressure heater and degassing in a combined cycle power plant, the degassing process unit Sub-controllers for controlling the operation of the storage tank by detecting a control variable including the level and flow rate and pressure of each storage tank of the; A DB processing apparatus for collecting and storing various control variables from the lower control apparatuses; Collecting control variables such as the water level, flow rate or pressure of the condenser, low pressure heater and deaerator from the DB processing device, and calculating integrated control processes based on various control variables, and calculating the operating variables generated as a result of the DB. An integrated upper control processing device for transmitting to the lower control device through the processing device; And a supervisory control device for collecting and storing data collected and stored in the DB processing device to control and monitor overall processes of the deaerator, and to selectively control a lower control or an integrated upper control which is an operation mode of the deaerator process unit. It features.

Specifically, the integrated upper control processing apparatus, the DCS interface connected to the DB processing apparatus and the supervisory control apparatus via a LAN for data communication; A configuration definition unit having a definition of a control variable and a definition of identification information and an operation method of a lower control device; A system model unit managing model parameter definitions; The system recognition unit sends a test signal to the lower control device to recognize the system of the deaerator process, collects the response results, automatically performs the recognition of the deaerator process unit, calculates the recognized parameters, and stores them in the system model unit. ; And control data collected from the DCS interface by using predefined information, collected from the DCS interface, and collected the disturbance variable and operation mode information to perform a multivariate model prediction algorithm. And a model predictive control unit which transmits the manipulated variable value obtained as a result of the calculation to the lower control apparatus through the DCS interface.

The configuration definition unit may include definitions of execution cycles and numbers of the integrated upper control processor, definition of upper and lower limits of control variables, disturbance variables, and operation variables, and network addresses of the DB processing unit, the monitoring control unit, and the lower control unit. And an operation mode tag definition, a tuning element variable value definition, and an initialization definition content of the variable.

The technical method of the present invention for achieving the above object is, in the combined cycle power plant in the method for controlling the degassing process of the degassing process unit including a storage tank such as a condenser, low pressure heater and degasser, The first step of collecting the configuration definition information, generating the necessary variables and parameters for model prediction, and performing the initialization of the weight factor; The integrated upper control processing apparatus may include collecting a driving mode from the monitoring control apparatus and collecting control variable and disturbance variable values from the monitoring control apparatus in the integrated control mode; A third step of calculating a control variable and disturbance matrix using the collected information; A fourth step of estimating and predicting a state of the degassing process by adjusting internal necessary parameter values after performing the calculating step and calculating using a Kalman filter; A fifth step of determining an operation variable that minimizes an objective function using the predicted value calculated above; And a sixth step of transmitting the operation variable value determined above to the corresponding lower control device and controlling the degassing process unit according to the transmitted operating variable.

Specifically, the first step, the collection step of determining the model information, controller information, DCS tag and connection information, etc. when applying to the degassing process of the combined cycle process to store in a file form (csv, txt, etc.); An initialization step of generating matrix values of Sx, Sd, and Su as shown in Equation 14 and performing initialization of the weight matrix for model prediction of the integrated upper control processor; The integrated upper control processing device may include: a connection step of attempting connection connection with the monitoring control device using the DCS connection information; And a mode determination step of determining whether the operation mode is an integrated control mode by collecting the operation mode of the degassing process from the monitoring and control device.

Before performing the collecting step, determining whether to select a mathematical model and an experimental model of the process; Collecting information necessary for defining a mathematical model when the mathematical model is selected; Performing model calculation using an equation such as a load balancing equation; Determining the model by determining whether the calculated model is accurate by comparing with the existing operational data; And redefining the parameter by changing and modifying the parameter when the calculated model is inappropriate and needs to be redefined.

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

2 is a view showing an integrated control concept in a degasser process of a combined cycle power plant according to the present invention, the degasser process unit 1, the lower control unit (20, 40, 60) and the integrated upper control processor (100) It is shown.

That is, the degassing process unit 1 has a plurality of storage tanks, the storage tank is a condenser (10; condenser), low pressure heater (30; LP heater) and the degasser (Dearator 50).

The condenser 10 is configured to receive some steam discharged from the turbine and convert it into condensate through a predetermined cooling process and then transfer the generated condensate to the deaerator 50, and the low pressure heater 30 ) Is provided to receive some steam discharged from the turbine to perform heat exchange with hot water supplied to district heating, and to deliver the heat-exchanged condensate to the degasser 50, wherein the degasser 50 is The condensed water discharged from the condenser 10 and the low pressure heater 30 is received and stored, and is configured to remove impurities contained in the condensed water and supply it to the boiler side.

In addition, in the combined cycle power generation process, the water level control of the degasser 50, the water level control of the condenser 10, and the water level control of the low pressure heater 30 serve as important control processes in the control of the boiler and the turbine.

Therefore, in the present invention, as shown in FIG. 2, the water level data from the water level sensor LT of each of the storage tanks 10, 30, and 50 in order to configure the multi-variable integrated level control processing apparatus 100 of the degassing process. The flow controller (FC) of the lower controllers 20, 40, and 60, which are directly accepted as input variables (CV; Controlled Variable) of the integrated upper control processor 100 and are cascaded, are connected to the loop controller. ) Is connected to the output variable (MV; Manipulated Variable) of the integrated upper control processor (100). Of course, the flow rate and pressure data detected through the flow rate sensor FT and the pressure sensor PT may be input as the control variable CV of the integrated high-level control processing apparatus 100 as well. In addition, a disturbance variable (DV) may also be connected by a measurement signal.

In addition, the configuration of the degasser process unit 1 and the lower control apparatus 20, 40, 60 to which the present invention is applied is the same as that of FIG. In case of only local control by the lower control device, the flow controller (FC) of each storage tank directly controls the flow control valve based on the data inputted from the water level controller (LC) and the flow sensor (FT). In the case of the integrated control by the control processing device 100, the operation variable value MV is output to the flow controller FC of each storage tank to collectively control the overall process of the deaerator process unit 1 in FIG. It is different.

3 is a view showing the detailed configuration of the integrated upper control processing apparatus associated with the lower control apparatus according to an embodiment of the present invention, the degassing process unit 1, the lower control apparatus (5), DB processing apparatus 70, The monitoring control device 80 and the integrated upper control processing device 100 is configured.

The lower control device 5 is configured to detect the control variable (CV) including the water level, flow rate and pressure of each storage tank (10, 30, 50) of the degassing process unit 1 to control the operation of the storage tank. It is.

The DB processing apparatus 70 is configured to collect and store various control variables CV from the lower control apparatuses 5.

The integrated upper control processing apparatus 100 collects control variables CV such as the water level and the flow rate or the pressure of the condenser 10, the low pressure heater 30, and the degasser 50 from the DB processing apparatus 70, respectively. The integrated control process is calculated based on various control variables, and the operation variable MV generated as a result of the calculation is transmitted to the lower control device 5 through the DB processing apparatus 70.

The supervisory control device 80 collects and stores data collected and stored in the DB processing device 70 to control and monitor and manage various processes of the deaerator, as well as subordinate control or integrated upper control, which is an operation mode of the deaerator process unit 1. Is configured to control selection.

As shown, the distributed control system 90 (DCS, Distributed Control System) including the lower control unit 5, the DB processing unit 70 and the supervisory control unit 80 of the deaerator process unit 1 below The overall system is configured with the integrated upper control processing apparatus 100 as a higher level.

That is, the lower control device 5 is located in the form of a remote control system (RCS) or tele-monitoring and tele control station (TM / TC) in the monitoring control device 80, so that each process data (water level information of the storage tank, Flow rate information, pressure information, disturbance information, etc.) are collected to perform real-time collection and local control.

Real-time data is stored and managed in the DB processing unit 70 of the distributed control system 90 via LAN, and the collected and stored data is managed by the supervisory control device 80 of the distributed control system 90. The supervisory control device 80 allows an operator to select the local control mode or the integrated control mode by the distributed control system 90.

Information necessary for operating the integrated upper control processing apparatus 100 is collected by the DCS interface 110 through the LAN, and after the integrated control process is calculated and performed in the integrated upper control processing apparatus 100, the DCS interface ( It is transmitted to the remote control value of the lower control device 5 through the DB processing unit 70 of the distributed control system 90 through 110 to perform the integrated control.

The detailed configuration of the integrated upper control processing apparatus 100 operating in this way, the DCS interface 110, the configuration defining unit 120, the system model unit 130, the system recognition unit 140, the model prediction control unit 150 And control means 160, input / output means 170, and storage unit 180, the distributed control system 90 includes a lower control unit 5, DB processing unit 70 and supervisory control unit ( 80).

The DCS interface 110 of the integrated upper control processing device 100 is configured to communicate with the DB processing device 70, the monitoring control device 80 and the lower control device 5 through a LAN for data communication. The configuration defining unit 120 is configured to define the control variable definition and the configuration of the identification information and the operating method of the lower control device 5, the system model unit 130 is configured to manage the model parameter definitions, The system recognition unit 140 sends a test signal to the lower control device 5 to recognize the system of the deaeration process, collects the response result, and automatically recognizes the deaeration process unit 1 to recognize the deaeration process. The parameter is calculated and stored in the system model unit 130, and the model predictive control unit 150 is operated according to a predetermined period by using the predefined information, the control variable collected from the DCS interface 110 (Controlled varia ble), the disturbance variable and operation mode information are collected to perform a multivariate model prediction algorithm to calculate the control data, and the manipulated variable value obtained as a result of the calculation is obtained through the DCS interface 110. It is configured to transmit to the lower control device (5).

That is, the configuration definition unit 120 has a function of defining and operating the integrated high level control processing apparatus 100, and defining (such as execution cycle and number) and variables of the integrated high level control processing apparatus 100. Includes information such as definition (upper / lower limit of CV, MV and DV variables, DCS connection tag), DCS configuration definition (network address, operation mode tag), variable value of tuning factor, definition of initialization of variable, etc. have. For this purpose, the information is monitored and stored through the input / output means 170.

The system model unit 130 manages model parameter definitions of the integrated upper control processing apparatus 100.

The system recognition unit 140 sends a test signal to the lower control device 5 to recognize the system of the degassing process, collects the response result, automatically recognizes the process system, and calculates the recognized parameter. To store in the system model unit 130.

In addition, the model predictive control unit 150 (MPC, Model Predictive Control) is operated according to a specified period by using information defined offline, the CV (Controlled variable) collected from the DCS interface 110, DV ( Disturbance variable, Disturbance variable and operation mode information are collected to perform the multivariate model prediction algorithm to calculate the control data, MV (manipulated variable) value obtained as a result of the sub-control through the DCS interface 110 To the device 5.

In the distributed control system 90, the information necessary in the degassing process unit 1 of the combined cycle power generation is collected and controlled by the local control logic in the lower control device 5.

On the other hand, the DB processing unit 70 of the distributed control system 90 collects and manages the data information of the process, and processes the CV, DV, and MV information required by the integrated high-level control processing unit 100 to transmit and receive data. Play a supporting role.

In addition, the supervisory control device 80 stores the information about the information defined in the distributed control system 90 in relation to the integrated upper control processor 100, stores it as tag information, and monitors it. The operation results of the control processing apparatus 100 are managed by various types of display methods (trends, graphics, etc.). In addition, the supervisory control device 80 allows operation selection by the integrated upper control processing device 100 and the lower control device 5.

4 is a view illustrating a model predictive control algorithm of the model predictive control unit according to an embodiment of the present invention. The model predictive control unit 150 includes a system superstructure unit 151, a model state upgrade unit 153, and a model predictive value calculation unit. 155 and the optimum operation variable calculation unit 157.

The system superstructure unit 151 is configured to collect the control variables, disturbance variables and various parameters for prediction required by the model prediction controller 150 through the DCS interface 110, the model state upgrade unit 153 is The prediction is performed using the information collected in Equation 3 below, but the state estimation for the prediction is performed to upgrade the state by the Kalman filter of Equation 4 below.

The model prediction calculator 155 tunes the control performance of the model prediction controller 150 by changing a Kalman Gain value, and adjusts the tuning parameter to reflect the model error in the state estimate. The optimum operating variable calculation unit 157 performs the prediction after p-step using Equation 3 below according to the estimated state, and calculates the objective function (J) of Equation 5 below. ) Is calculated to be minimized and outputted to the lower control device 5 through the DCS interface 110 with the manipulated variable (MV) value.

That is, the configuration defining unit 120 of the integrated upper control processing apparatus 100 manages the characteristic data of the model predictive control unit 150 (MPC), and transmits information including information about the model to the system superstructure unit 151. ) To store the necessary information of the model information in the storage unit 180 in the integrated upper control processing apparatus (100).

The definition of the model of the model prediction controller 150 is defined as an output disturbance model, as shown in FIG. 5. This model is the part that the feedback control is responsible for the model error, the influence of the disturbance that is not measured, but the output disturbance that is independently subscribed to each output to enhance the control performance and to easily adjust the model predictive control unit 150. Expressed as

And these signals are assumed to be first-order filtered and integrated white noise. This disturbance model is known to reflect the estimated nature of actual disturbance. The state equation for this is shown in Equation 1 below.

Here, x (k) represents a state variable indicating the system state, u (k) corresponds to the input variable of the process, that is, the operation variable (MV) that is the output variable of the integrated upper control processor 100, y ( k) corresponds to the control variable CV of the integrated phase control processing apparatus 100 as an output variable of the process. D (k) corresponds to DV of the integrated phase control processing apparatus 100 as a disturbance variable, w (k) denotes a process error, and v (k) denotes a measurement error.

The difference of time is performed in the difference equation of the system, and the state equations for this are rearranged as in Equation 2 below.

here,

to be.

The p-step prediction for this is expressed by Equation 3 below.

here,

to be.

The system superstructure 151 stores the variables and parameters (Sx, Sd, Su, A, B, C, D, etc.) necessary for the model prediction controller 150 to prepare for the online calculation later. . In the case of the construction of the online algorithm, the CV, DV variables and related tag information related to the integrated upper control processing apparatus 100 collected by the DB processing apparatus 70 of the distributed control system 90 are combined. The data is collected through the data input unit 111 in the DCS interface 110.

The collected information is predicted by the model state upgrade unit 153 as shown in Equation 3, and it is necessary to estimate a state variable value for this. The state estimation is to upgrade the state by the Kalman filter as shown in Equation 4 below.

; Kalman gain)은 아래와 같다.Where Kalman gain (

; Kalman gain is shown below.

; Kalman gain)의 값을 변경하여 모델예측제어부(150)의 제어성능을 튜닝할 수 있게 된다. Here, f _ai is to provide a function of the tuning parameter (tuning parameter), the operator can monitor and tune on the monitor that is the input and output means of the integrated upper control processor 100. By adjusting f _ai between 0 and 1, the Kalman gain (

; It is possible to tune the control performance of the model prediction controller 150 by changing the value of Kalman gain).

At this time, as f _ai is close to 1, the model error is reflected to state estimation more strongly, and as f _ai is close to 0, the model error is estimated as state estimation. I want to reflect it a little bit and slowly minimize it. This is the same effect as adjusting the ratio of Q / R, which is the weighting factor of the objective function.

In other words, as the Q / R ratio is increased, the error is more strongly minimized, so that the input moves relatively freely and the process output tracks the reference quickly. The smaller the Q / R ratio, the more the input movement is minimized, resulting in a relatively slow input movement and the effect that the process output follows the reference slowly.

Where P represents the covariance matrix for the estimation error. According to the estimated state, the prediction after pstep is performed by using Equation 3, and the optimum operation variable calculating unit 157 calculates M to minimize the objective function J of Equation 5 below by MV. It will be used as a value.

Equation 6 below represents an input size constraint, an input change constraint, and an output size constraint of the process.

The input change value is calculated using quadratic programming (QP) considering constraints. The calculated input change value is output through the data output unit 115 in the DCS interface 110 of the integrated upper control processor 100, and this value is used as a multivariate control value in the degassing process of the combined cycle process. do.

6 is a flowchart showing the operation of the integrated upper control processing apparatus according to the present invention.

First, in the configuration definition information collection process (S11), the model information, the controller information, the DCS tag, and the connection information are determined when the degassing process of the combined cycle process is applied and stored in a file form (csv, txt, etc.).

In the initialization process (S12) of the integrated upper control processing apparatus 100, matrix values such as Sx, Sd, and Su for model prediction are generated by using Equation 3 and initialization of the weight matrix Q and R is performed. .

In the DCS connection connection process (S13) of the integrated upper control processing apparatus 100, the connection control with the distributed control system 90 is attempted using the DCS connection information.

In the status check process (S14), it is checked whether there is a communication error, and when an error occurs in this process, an alarm is generated to the operator in the alarm generating process (S14-1). In addition, in the normal case, the cycle operation through the connection with the lower control apparatus 5 is continuously performed by the repeating process (S26).

In addition, the basic state information checking process (S15) collects the operation mode from the distributed control system 90. In the DCS / MPC mode checking process (S15), the operation mode is checked according to the collected information, and when the control mode is not the integrated control mode (MPC), the sub-control device (5) according to the local control process (S25) of the distributed control system 90 Degassing process control by) is performed.

When the control mode is the integrated control mode, the control variable CV and the disturbance variable DV of the integrated upper control processor 100 are collected from the DCS information collection process S17, respectively. Using the collected information, the CV matrix is calculated in step S18, and the DV matrix is calculated in step S19. The control variable CV and the disturbance variable DV are calculated based on Equations 1 and 2.

In addition, in the other variable matrix calculation process (S20), the internal necessary variable values are tuned, and in the state estimation and prediction process (S21), the state of the distributed control system is estimated using the Kalman filter as shown in Equation 4 above, Will be performed. In the MV calculation process S22 using the predicted value calculated from the calculation process, the MV value by the quadratic equation programming method considering the optimal objective function is determined using Equation 5 above.

The determined MV value transmits the MV value to the lower control device 5 in the MV transmission process S23, and performs control by the lower control device 5 in the MV control process S24, thereby removing the combined thermal process. It will control the instrument process.

7 is a flowchart illustrating a process model recognition process for collecting configuration definition information according to the present invention.

First, in the model selection process (S1), which is a preliminary process for collecting the configuration definition information of FIG. 6, a determination is made as to whether to select a mathematical model and an experimental model of the process, and in the configuration definition information collection process (S2), a mathematical model Gather the information you need for definition.

In the mathematical model calculation process (S3), model calculation is performed using an equation such as a load balancing equation, and in the model determination process (S4), it is compared with existing operating data to determine whether the calculated model is accurate. do.

If the calculated model is inappropriate and needs redefinition, the parameter is changed and modified in the process of redefining the parameter (S5), and repeated.

On the other hand, when the process model recognition method according to the experimental method is determined in the above (S1), when the necessary parameter information (collection data period, etc.) is determined in the configuration definition information collection process (S6), the test reference information recording process ( In S7) the test signal is transmitted through the lower control device (5). At this time, the transmission signal sends a unit response signal. This information becomes the MV value of the deaerator process.

In the online information collection process S8, the CV signal of the deaerator process operated after the reference signal generation is collected and stored.

In the model recognition calculation process (S9), the model recognition is automatically calculated. In the model information storage process (S10), the configuration definition information of the integrated upper control processing apparatus 100 used in the degassing process is used for the model determined by the equation or the experiment.

On the other hand, while the present invention has been shown and described with respect to specific preferred embodiments, various modifications and changes of the present invention without departing from the spirit or field of the invention provided by the claims below It can be easily understood by those skilled in the art.

As described above, the present invention provides three storage tanks related to the degassing process by applying a multi-variable model predictive control method during the degassing, condenser, and low pressure heaters in the degassing process of the combined cycle power plant. , Condenser, low pressure heater) can satisfy the high / low-limit conditions of the water level, and even if mutual interference occurs during the control of each process, it is possible to easily and optimally achieve comprehensive control of the multi-variables to improve the control performance and efficiency of the process. There is an advantage to that.

In addition, by implementing integrated control for the degassing process of the combined cycle power generation, it is possible to adjust various factors, so that the tuning of the control system is easy and the system can be easily monitored and managed from the operator's point of view. .

Claims (12)

In the system for controlling the degassing process of the degassing process unit, including storage tanks such as condenser, low pressure heater and degassing in the combined cycle power plant, Lower control devices that detect the control variables including the water level, the flow rate and the pressure of each storage tank of the degassing process unit to control the operation of the storage tank; A DB processing apparatus for collecting and storing various control variables from the lower control apparatuses; Collecting control variables such as the water level, flow rate or pressure of the condenser, low pressure heater and deaerator from the DB processing device, and calculating integrated control processes based on various control variables, and calculating the operating variables generated as a result of the DB. An integrated upper control processing device for transmitting to the lower control device through the processing device; And And a supervisory control device for collecting and storing data collected and stored in the DB processing device to control and monitor and manage various processes of the deaerator, and to selectively control a lower control or an integrated upper control which is an operation mode of the deaerator process unit. Integrated control system for degassing process of combined cycle power plant. The method according to claim 1, The integrated upper control processing device, A DCS interface connected to the DB processing apparatus and the supervisory control apparatus for data communication through a LAN; A configuration definition unit having a function of defining control variables, identification information of the lower control device, and an operation method; A system model unit managing model parameter definitions; A system that sends a test signal to the lower control device to recognize a system of a degasser process, collects a response result, automatically recognizes a degasser process unit, calculates a recognized parameter, and stores it in the system model unit. Recognition unit; And Controlled data collected from the DCS interface by using predefined information and collected from the DCS interface, collected by the disturbance (Disturbance variable) and operating mode information to perform a multivariate model prediction algorithm to control data And a model predictive control unit for transmitting a calculated value of the manipulated variable obtained as a result of the calculation to the subordinate control device through the DCS interface. The integrated control for the degassing process of the combined cycle power plant, comprising: system. The method according to claim 2, The configuration defining unit, Definition of the execution cycle and number of the integrated upper control processor, definition of upper / lower limits of control variable, disturbance variable and operation variable, network address and operation mode tag of the DB processing unit, supervisory control unit and lower control unit. Integrated control system for the degassing process of a combined cycle power plant, characterized in that the definition, the definition of the tuning element variable value, and the initialization definition of the variable. The method according to claim 2, The model prediction control unit, A system super-institution unit for collecting control variables, disturbance variables, and various parameters for prediction through the DCS interface; The collected information performs prediction as shown in Equation 7 below, but the state estimation for prediction includes a model state upgrade unit for upgrading the state by the Kalman filter shown in Equation 8 below; A model prediction calculator for changing a Kalman filter and tuning the control performance of the model prediction controller, adjusting and adjusting a ratio of reflecting a model error to a state estimate by adjusting a tuning parameter value; And According to the state estimated by the model state upgrade, the following equation (7) is performed to perform prediction after a predetermined step (P), and the operation variable (ΔU) for minimizing the objective function (J) of Equation 9 is calculated. And an optimum operation variable calculation unit for outputting to the lower control device through the DCS interface by using this as an operation variable value. The integrated control system for the degassing process of the combined cycle power plant, characterized in that it comprises a.

here,

Where Sx, Sd, Su, A, B, C, and D are parameters for prediction.

Where Kalman gain (

; Kalman gain)

Where f _ai is a tuning parameter.

Where J is the objective function and ΔU (t) is the manipulated variable (MV) value. The method according to claim 4, The model predictor calculator adjusts a tuning parameter between 0 and 1, but as the tuning parameter approaches 0, the model predictor gradually reflects a model error to state estimation to slowly minimize the model error. The closer to 1, the more control model for the degassing process of the combined cycle power plant, characterized in that it has a characteristic to strongly minimize the model error by reflecting the model error in the state estimate. In the method for controlling the deaeration process of the deaeration process unit including a storage tank such as a condenser, low pressure heater and deaerator in a combined cycle power plant, The integrated upper control processing apparatus may include: a first step of collecting an operation mode from the monitoring control apparatus and collecting control variable and disturbance variable values from the monitoring control apparatus in the integrated control mode; A second step of calculating a control variable and disturbance matrix using the collected information; A third step of estimating and predicting a state of the degassing process by adjusting internal necessary parameter values after performing the calculating step and calculating using a Kalman filter; A fourth step of determining an operation variable for minimizing an objective function using the predicted value calculated in the third step; And A fifth step of transmitting the determined operation variable value to the corresponding lower control device, and controlling the degassing process unit according to the transmitted operating variable; for the degasser process of the combined cycle power plant Integrated control method. The method according to claim 6, The control variable and the disturbance variable in the second step is calculated based on the following equation (10) and (11).

Here, x (k) is a state variable representing a system state, u (k) is an output variable (MV) of the integrated high level control processing apparatus which is an input variable of the process, and y (k) is an integrated variable as an output variable of the process. The control variable (CV) of the control processing device, d (k) is the disturbance variable, DV of the integrated high-level control processing device, w (k) is the process error, v (k) is the measurement error.

here,

being. The method according to claim 6, The state estimation of the third step is estimated by the equation of the Kalman filter as shown in Equation 12 below.

Here, Kalman

; Kalman gain)

F _ai is a tuning parameter. The method according to claim 6, The operation variable value of the fourth step is determined based on Equation (13) below, the integrated control method for the degassing process of the combined cycle power plant.

Where J is the objective function and ΔU (t) is the manipulated variable (MV) value. The method according to claim 6, Before performing the first step, A collection step of determining model information, controller information, DCS tag, connection information, and the like, when applying them to the degassing process of the combined cycle process and storing them in a file form (csv, txt, etc.); An initialization step of generating matrix values of Sx, Sd, and Su as shown in Equation 14 and performing initialization of the weight matrix for model prediction of the integrated upper control processor; The integrated upper control processing device may include: a connection step of attempting connection connection with the monitoring control device using the DCS connection information; And a mode determination step of determining whether the operation mode is an integrated control mode by collecting the operation mode of the degassing process from the monitoring and controlling device.

here,

being. The method according to claim 10, Before performing the collection step, Determining whether to select a mathematical model or an experimental model of the process; Collecting information necessary for defining a mathematical model when the mathematical model is selected; Performing model calculation using an equation such as a load balancing equation; Determining the model by determining whether the calculated model is accurate by comparing with the existing operational data; And redefining the parameters by changing and modifying the parameters when the calculated model is not suitable and redefinition is necessary. The method according to claim 11, When the experimental model is selected instead of the mathematical model, determining necessary parameter information and transmitting a test signal to a lower control apparatus through a DB processing apparatus; Collecting and storing control variables of a deaerator process through a DB processing apparatus after transmitting the test signal; And automatically calculating and recognizing a model through the control variable and storing model information. The integrated control method for a degasser process of a combined cycle power plant, characterized in that for performing.

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