A dynamic control method and system for a steam power system

Abstract

The application provides a dynamic control method and system of a steam power system, and relates to the technical field of the steam power system; the method comprises the following steps: dividing the steam power system into multiple control subsystems, determining input information and output information of the control subsystems; respectively establishing multiple subsystem linear model families based on the evolution degrees of different control subsystems; obtaining corresponding controller sequences according to the subsystem linear model families; inputting current input information into the control subsystems and the subsystem linear model families respectively, and obtaining physical output quantities and model output quantities correspondingly; obtaining an arbitration vector according to the physical output quantities and the model output quantities; selecting an optimal controller from the controller sequences based on the arbitration vector, and realizing dynamic control of the steam power system by using the optimal controller. The application solves the problem that the equipment characteristics of the steam power system evolve in a long service life, and then the steady-state control precision of the steam power system is weakened and the dynamic response performance is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steam power system, and particularly relates to a dynamic control method and system of a steam power system. BACKGROUND

[0002] The steam power system is the power source of a ship, a power plant and a nuclear power plant, and the control level thereof affects the response speed and energy utilization efficiency in the switching process of different power levels and has an important influence on the power output capacity.

[0003] The steam power system has a long working time, and the overall operation time is as short as ten years or even several decades, so that the equipment characteristics inevitably change in the whole life cycle of the steam power system. The steam power system includes a large number of equipment, and the performance of the equipment inevitably changes in a long time, such as pump valve flow deviation, pipeline flow resistance increase, heat transfer equipment heat transfer capacity weakening, actuator jamming and response delay, and the like; therefore, the control performance of the steam power system is not maintained.

[0004] At present, the control algorithm and control parameters of the steam power system are usually fixed, and it is difficult to adapt to the control requirements of the steam power system in the case of equipment characteristic change in the whole life cycle. Mainly manifested in: with the passage of time, the steady-state control accuracy and dynamic response speed of the steam power system will gradually decrease; especially when the equipment characteristic changes are large enough, the closed-loop feedback control system even has the risk of instability, which may have a great impact on the safe operation of the steam power system.

[0005] Therefore, a method is needed to solve the problem of the influence of equipment characteristic change on the control performance. SUMMARY

[0006] Therefore, it is necessary to provide a dynamic control method and system of a steam power system to solve the problem that the equipment characteristics of the steam power system change in the long life cycle, and then the steady-state control accuracy and dynamic response performance of the steam power system are reduced.

[0007] In one aspect, the present application provides a dynamic control method of a steam power system, which comprises:

[0008] The steam power system is divided into a plurality of control subsystems, and the input information and the output information of the plurality of control subsystems are determined;

[0009] A plurality of subsystem linear model families are respectively established based on the change degrees of different control subsystems, and a corresponding controller sequence is obtained according to the subsystem linear model families;

[0010] inputting the current input information into the control subsystem and the subsystem linear model family respectively, and obtaining physical output quantity of the control subsystem and model output quantity of the subsystem linear model family correspondingly;

[0011] obtaining an arbitration vector according to the physical output quantity and the model output quantity, and selecting an optimal controller from the controller sequence based on the arbitration vector, and using the optimal controller to realize dynamic control of the steam power system.

[0012] Further, the control subsystem is divided according to minimum control units, and each control unit includes one or more devices.

[0013] Further, the subsystem linear model family is a combination of second-order or lower dynamic links or simple links in series or parallel.

[0014] Further, the degree of evolution includes an evolution feature of the device and an evolution value corresponding to the evolution feature.

[0015] Further, the arbitration vector is obtained by:

[0016] obtaining a deviation vector by subtracting the model output quantity from the actual physical output quantity of the subsystem linear model family, and obtaining an arbitration vector based on the deviation vector.

[0017] Further, the deviation vector is:

[0018] ;

[0019] wherein, ; the model output quantity is represented by y; the physical output quantity is represented by y.

[0020] Further, the arbitration vector is:

[0021] ;

[0022] wherein, ; and the adjustment coefficient is represented by ki; the starting time of integration is represented by t0, which is the starting time of the variable working condition; the ending time of integration is represented by te, which is determined according to the length of the dynamic process of the subsystem.

[0023] Further, the optimal controller is the controller of the subsystem linear model family corresponding to the minimum value in the arbitration vector.

[0024] Further, the degeneration characteristics include any one or more of a degeneration rate, a degeneration thickness, a pump valve flow offset, a jam, a pipeline flow resistance, a heat transfer of a heat exchange device, a response delay of an actuator, and a blade damage.

[0025] In another aspect, the present application also provides a dynamic control system of a steam power system, comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of any one of the above methods.

[0026] In general, the present application provides a dynamic control method and system of a steam power system, which can achieve the following beneficial effects compared with the prior art:

[0027] According to the degeneration characteristics and values of different control subsystems of the steam power system, the present application designs multiple corresponding controllers, and through online degeneration detection, timely switches to the optimal controller according to the arbitration vector to realize effective control of different control subsystems, thereby adaptively meeting the control requirements when the equipment characteristics degenerate, largely avoiding that the degeneration of the equipment characteristics greatly weakens the control performance of the steam power system, effectively solving the problems of reduced control accuracy and even possible instability of the closed-loop control system of the steam power system due to the degeneration of the long-life equipment characteristics, and providing strong technical support for high-performance control and high-safety operation of the steam power system. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0029] Figure 1 is a method flowchart of a dynamic control method and system of a steam power system provided by the present application;

[0030] Figure 2 is a control subsystem schematic diagram of a dynamic control method and system of a steam power system provided by the present application;

[0031] Figure 3 is a closed-loop feedback control schematic diagram of a control subsystem of a dynamic control method and system of a steam power system provided by the present application;

[0032] Figure 4 is a pole distribution schematic diagram of a dynamic control method and system of a steam power system provided by the present application;

[0033] Figure 5A switching control schematic diagram of a dynamic control method and system of a steam power system is provided. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be described below in conjunction with the accompanying drawings and embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of the present application.

[0035] It should be noted that, in the description of the embodiments of the present application, the terms “comprise”, “contain” or any other variants thereof are intended to cover non-exclusive inclusion, so that the method, step or system comprising a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes elements inherent to such method, step or system. Without more limitations, the element defined by the statement “comprises a” does not exclude the presence of another identical element in the method, step or system comprising the element.

[0036] In order to effectively cope with the influence of equipment characteristic evolution in long life cycle on the control process of the steam power system, and ensure that the steam power system has excellent dynamic control performance and steady-state control accuracy in the whole life cycle, the present application provides a dynamic control method and system of a steam power system. Specifically, as shown in Figure 1 the method comprises:

[0037] Step 101: dividing the steam power system into multiple control subsystems, and determining the input information and output information of the multiple control subsystems.

[0038] Among them, the control subsystem is divided according to the minimum control unit, and each control unit includes one or more devices. For example, as shown in Figure 2 the control subsystem is a feedwater system, which includes an electric motor, a centrifugal pump water pump, a feedwater flow regulating valve, and a steam generating device, the input information (control variable) of the control subsystem is determined as the regulating valve opening, and the output information (controlled variable) is determined as the feedwater flow.

[0039] Step 102: respectively establishing multiple subsystem linear model families based on the evolution degree of different control subsystems; and obtaining a corresponding controller sequence according to the subsystem linear model family.

[0040] It should be noted that the degree of degradation includes the degradation characteristics of the equipment and the degradation values corresponding to the degradation characteristics. The degradation of the equipment characteristics over time is usually a gradual process, and the degradation characteristics and degradation values can be obtained through long-term operation data or through special tests.

[0041] Further, the degradation characteristics include any one or more of the following: degradation rate, degradation thickness, pump valve flow deviation, sticking, pipeline flow resistance, heat transfer of heat exchange equipment, actuator response delay, and blade damage.

[0042] According to the difference in the degree of degradation, a linear model family of the control subsystem corresponding to the degree of degradation is established . One control subsystem includes one or more equipment, and one control subsystem corresponds to a subsystem linear model family for describing the degree of degradation of the one or more equipment set.

[0043] Preferably, the subsystem linear model family is a combination of second-order or lower-order dynamic links or simple links in series or parallel.

[0044] As a specific embodiment, when the degraded equipment is a regulating valve, the degradation characteristic is sticking, that is, the response speed is slow. According to the difference in the degree of sticking, the linear model of the control subsystem includes:

[0045] ;

[0046] wherein, represents the gain of the dynamic link; represents the time constant of the dynamic link; represents a complex variable.

[0047] As another embodiment, when the degraded equipment is a feedwater pump, the degradation characteristic is blade damage, that is, the water supply capacity is weak. According to the difference in the degree of blade damage, the linear model of the control subsystem includes:

[0048] ;

[0049] wherein, represents the gain of the dynamic link; represents the time constant of the dynamic link; represents a complex variable.

[0050] It should be noted that, as shown in Figure 3 , the design principle of the controller sequence is to ensure that the poles of the closed-loop control system formed by each controller and the corresponding linear model are distributed in the pole plane area. As shown in Figure 4 , the hatched area in the left half plane is the pole plane area.

[0051] Preferably, the poles are distributed in the pole plane region and have the same pole location, so that the overshoot of the controlled variable does not exceed the limit. This ensures the stable operation of the controlled subsystem; simultaneously, it ensures the rise time is no greater than [a certain value]. This ensures that the dynamic response of the output of the controlled subsystem is fast enough.

[0052] For example, such as Figure 4 As shown, damping ratio Take 0.7 as the overshoot of the water supply flow rate (controlled variable). The percentage should not exceed 5%, ensuring the stable operation of the nuclear power plant's feedwater system; natural damping frequency. Take 0.6 as the rise time of water flow rate under varying operating conditions. The response time should not exceed 3 seconds to ensure a sufficiently fast dynamic response process.

[0053] Step 103: Input the current input information into the control subsystem and the linear model family of the subsystem respectively, and obtain the physical output of the control subsystem and the model output of the linear model family of the subsystem.

[0054] Specifically, such as Figure 5 As shown, the current input information (control quantity) will be displayed. This is applied to the control subsystem, that is, the opening degree of the regulating valve is applied to the water supply system, and the physical output is measured. At the same time, the current input information (control quantity) will be... This applies to a family of linear models, meaning that the valve opening is simultaneously used as the control variable. By inputting a family of linear models, we obtain the calculated water flow rates corresponding to each linear model, which are the model outputs. .

[0055] Step 104: Obtain the arbitration vector based on the physical output and the model output; select the optimal controller from the controller sequence based on the arbitration vector, and use the optimal controller to realize the dynamic control of the steam power system.

[0056] As an example, obtaining the arbitration vector includes: subtracting the model output from the actual physical output of the subsystem's linear model family to obtain the deviation vector; and obtaining the arbitration vector based on the deviation vector.

[0057] More specifically, the deviation vector for: ;in, ; Indicates the model output; This represents the physical output quantity.

[0058] based on The expression of the arbitration vector. Specifically, the arbitration vector is: ; wherein, ; and denotes the adjustment coefficient; denotes the starting time of the integral, which is the starting time of the variable working condition; denotes the ending time of the integral, which is determined according to the length of the dynamic process of the subsystem. Preferably, the trend deviation is selected to obtain the arbitration vector, , .

[0059] Preferably, the optimal controller is the controller of the linear model family corresponding to the minimum value in the arbitration vector.

[0060] For example, the minimum rule is used as the arbitrator, that is, the minimum value in the arbitration vector is selected, and the linear model corresponding to the minimum value of each is used as the most matched model of the current control subsystem, and then the optimal controller corresponding to the linear model family is obtained. At the same time, the optimal controller is switched to implement control, thereby completing the online switching of multiple controllers.

[0061] In another aspect, the present application provides a dynamic control system of a steam power system, comprising a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to realize the steps of the method according to any one of the preceding aspects.

[0062] More specifically, the dynamic control system further comprises three functional modules of a linear model family, a controller sequence and an arbitrator. The technical solution of the system is consistent with the technical solution of the method, which will not be described here.

[0063] It should be noted that, for the foregoing various embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the order of the described actions, according to the present application, certain steps can be performed in other order or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0064] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments. In the several embodiments provided in the present application, it should be understood that the disclosed method or system can be implemented in other ways. For example, the above-described embodiments are merely illustrative, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0065] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or they can be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0066] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0067] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable memory. Based on this understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product, which is stored in a memory and includes a plurality of instructions for making a computer device (which can be a personal computer, a server or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present application.

[0068] Those skilled in the art can understand that all or part of each circuit in the above embodiments can be realized by a program instructing related hardware, and the program can be stored in a computer readable memory, and the memory can include a flash disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0069] The above-described embodiments are merely exemplary and do not limit the present disclosure. Any equivalent changes, modifications, and improvements made to the present disclosure by those skilled in the art are construed as falling within the scope of the present disclosure. The present disclosure is intended to cover any and all such equivalent changes, modifications, and improvements. The scope of the present disclosure is defined by the appended claims rather than the foregoing description.

[0070] Any technical features in the above embodiments can be combined, and for brevity, not all possible combinations are described, and any combination of features described herein is within the scope of the present disclosure, unless such a combination is not technically possible.

[0071] Those skilled in the art easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of dynamic control of a steam power system, characterized by, The method comprises: dividing the steam power system into a plurality of control subsystems, determining input information and output information of the plurality of control subsystems; respectively establishing a plurality of subsystem linear model families based on the degree of evolution of different control subsystems; and obtaining a corresponding controller sequence according to the subsystem linear model families; respectively inputting the current input information into the control subsystems and the subsystem linear model families to obtain physical output quantities of the control subsystems and model output quantities of the subsystem linear model families; obtaining an arbitration vector according to the physical output quantities and the model output quantities; selecting an optimal controller from the controller sequence based on the arbitration vector, and using the optimal controller to realize dynamic control of the steam power system; Wherein the arbitration vector is: ； wherein, ; and denotes a regulation factor; denotes the starting time of the integral, which is the starting time of the variable working condition; denotes the ending time of the integral, which is determined according to the length of the dynamic process of the subsystem; ; denotes the model output quantity; denotes the physical output quantity.

2. A dynamic control method of a steam power system according to claim 1, characterized by, the control subsystems are divided according to minimum control units, and each control unit includes one or more devices.

3. A dynamic control method of a steam power system according to claim 1, characterized by, The subsystem linear model families are combination links formed by series or parallel connection of dynamic links of the second order or simple links.

4. A dynamic control method of a steam power system according to claim 3, characterized by, The degree of evolution includes an evolution characteristic of a device and an evolution value corresponding to the evolution characteristic.

5. A dynamic control method of a steam power system according to claim 1, characterized by, The arbitration vector is obtained by: subtracting the model output quantities from physical output quantities actually output by the subsystem linear model families to obtain a deviation vector; and obtaining the arbitration vector based on the deviation vector.

6. A dynamic control method of a steam power system according to claim 5, characterized in that, The bias vector Is: ； wherein ; denotes a model output quantity; denotes a physical output quantity.

7. A dynamic control method of a steam power system according to claim 1, characterized by, The optimal controller is a controller of a subsystem linear model family corresponding to the minimum value in the arbitration vector.

8. A dynamic control method of a steam power system according to claim 4, characterized by, The evolution characteristic includes any one or more of an evolution rate, an evolution thickness, a pump valve flow offset, a jam, a pipeline flow resistance, heat transfer of a heat exchange device, a response delay of an actuator, and blade damage.

9. A dynamic control system for a steam power system, comprising a memory, a processor and a computer program stored on the memory, characterized in that, The processor executes a computer program to implement the steps of the method of any one of claims 1-8.

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