Dynamic control method and system for steam power system

Abstract

The invention provides a dynamic control method and system for a steam power system, and relates to the technical field of steam power systems. The method comprises the steps that the steam power system is divided into a plurality of control subsystems, and input information and output information of the control subsystems are determined; respectively establishing a plurality of subsystem linear model families based on the development degrees of different control subsystems; obtaining a corresponding controller sequence according to the subsystem linear model family; respectively inputting current input information into the control subsystem and the subsystem linear model family to correspondingly obtain a physical output quantity and a model output quantity; 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 realizing dynamic control of the steam power system by using the optimal controller. According to the method, the problems that the steady-state control precision of the steam power system is weakened and the dynamic response performance is reduced due to development of equipment characteristics of the steam power system in a long life cycle are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of steam power systems, and in particular to a dynamic control method and system for a steam power system. Background Art

[0002] Steam power systems are the source of power for ships, power plants, and nuclear power plants. Their control level affects the response speed and energy utilization efficiency during the switching process of different power levels, and has an important impact on the ability to quickly output power.

[0003] Steam power systems have a long working time, generally ranging from a short ten years to several decades, which makes it inevitable that equipment characteristics will change during the entire life cycle of the steam power system. Steam power systems contain many devices, and during long-term operation, the performance of many devices will inevitably change, such as pump and valve flow deviation, increased pipeline flow resistance, reduced heat transfer capacity of heat exchange equipment, actuator jamming and response delay, etc.; therefore, it is not conducive to maintaining the control performance of the steam power system.

[0004] At present, the control algorithms and control parameters for steam power systems are usually fixed, which makes it difficult to adapt to the control requirements of steam power systems under the condition of equipment characteristics evolving during the entire life cycle. This is mainly manifested in that as time goes by, the steady-state control accuracy and dynamic response speed of the steam power system will gradually decrease; especially when the equipment characteristics evolve greatly enough, the closed-loop feedback control system may even have the hidden danger of instability, which may have a huge impact on the safe operation of the steam power system.

[0005] Therefore, there is an urgent need for a method to solve the problem of the impact of equipment characteristic evolution on control performance. Summary of the invention

[0006] Based on this, it is necessary to provide a dynamic control method and system for a steam power system to address the above-mentioned technical problems, which solves the problem that the equipment characteristics of the steam power system evolve over a long life cycle, thereby weakening the steady-state control accuracy and dynamic response performance of the steam power system.

[0007] In one aspect, the present invention provides a method for dynamic control of a steam power system, the method comprising: Dividing the steam power system into a plurality of control subsystems, and determining input information and output information of the plurality of control subsystems; Establishing multiple subsystem linear model families based on the evolution degree of different control subsystems; and obtaining corresponding controller sequences according to the subsystem linear model families; Inputting the current input information into the control subsystem and the subsystem linear model family respectively, and obtaining the physical output of the control subsystem and the model output of the subsystem linear model family accordingly; An arbitration vector is obtained according to the physical output and the model output; an optimal controller is selected from a controller sequence based on the arbitration vector, and the dynamic control of the steam power system is realized by using the optimal controller.

[0008] Furthermore, the control subsystem is divided according to minimum control units, and each of the control units includes one or more devices.

[0009] Furthermore, the subsystem linear model family is a combination link composed of dynamic links or simple links of the second order or below in series or in parallel.

[0010] Furthermore, the evolution degree includes the evolution characteristics of the equipment and the evolution value corresponding to the evolution characteristics.

[0011] Furthermore, obtaining the arbitration vector includes: The model output is subtracted from the physical output actually output by the subsystem linear model family to obtain a deviation vector; and an arbitration vector is obtained based on the deviation vector.

[0012] Furthermore, the deviation vector for: ; in, ; Represents the model output; Represents the physical output quantity.

[0013] Furthermore, the arbitration vector for: ; in, ; and represents the adjustment coefficient; Indicates the starting time of integration, which is the starting time of variable working conditions; Indicates the end time of the integration, which is determined by the length of the subsystem's dynamic process.

[0014] Furthermore, the optimal controller is the controller of the subsystem linear model family corresponding to the minimum value in the arbitration vector.

[0015] Furthermore, the evolution characteristics include: any one or more of evolution rate, evolution thickness, pump valve flow deviation, jamming, pipeline flow resistance, heat transfer of heat exchange equipment, actuator response delay, and blade damage.

[0016] On the other hand, the present invention further proposes a dynamic control system for 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.

[0017] In general, the present invention provides a dynamic control method and system for a steam power system, which can achieve the following beneficial effects compared with the prior art: The present invention designs a plurality of corresponding controllers according to the evolution characteristics and evolution values ​​of different control subsystems of the steam power system, and realizes effective control of different control subsystems by timely switching to the optimal controller according to the arbitration vector through online evolution detection, thereby adaptively meeting the control requirements when the equipment characteristics evolve, and avoiding to a large extent that the evolution of the equipment characteristics significantly weakens the control performance of the steam power system, and effectively solves the problem of reduced control accuracy of the steam power system due to the evolution of the equipment characteristics over a long life cycle, and even the problem of instability of the closed-loop control system, and provides strong technical support for high-performance control and high-safety operation of the steam power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of a dynamic control method of a steam power system and a method flow chart of the system provided by the present invention; Figure 2 It is a schematic diagram of a dynamic control method of a steam power system and a control subsystem of the system provided by the present invention; Figure 3 It is a schematic diagram of a dynamic control method of a steam power system and a closed-loop feedback control of a control subsystem of the system provided by the present invention; Figure 4 It is a dynamic control method of a steam power system and a pole distribution diagram of the system provided by the present invention; Figure 5 It is a dynamic control method of a steam power system and a schematic diagram of switching control of the system provided by the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the drawings and embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0021] It should be noted that, in the description of the embodiments of the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a method, step or system including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such method, step or system. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the method, step or system including the element.

[0022] In order to effectively deal with the impact of equipment characteristic evolution on the control process of the steam power system during its long life cycle and ensure that the steam power system has excellent dynamic control performance and steady-state control accuracy during its entire life cycle, the present invention proposes a dynamic control method and system for the steam power system. Specifically, Figure 1 As shown, the method includes: Step 101: Divide the steam power system into multiple control subsystems, and determine input information and output information of the multiple control subsystems.

[0023] The control subsystem is divided according to the smallest control unit, and each control unit includes one or more devices. Figure 2 As shown, the control subsystem is a water supply system, which includes a motor, a centrifugal pump, a water supply flow regulating valve and a steam generating device. The input information (control quantity) of the control subsystem is determined. To adjust the valve opening, output information (controlled quantity) The water supply flow rate.

[0024] Step 102: establishing a plurality of subsystem linear model families based on the evolution degrees of different control subsystems; and obtaining corresponding controller sequences according to the subsystem linear model families.

[0025] It should be noted that the evolution degree includes the evolution characteristics of the equipment and the evolution value corresponding to the evolution characteristics. The evolution of equipment characteristics over time is usually a gradual process, and the evolution characteristics and evolution values ​​can be obtained through long-term operation data or through special tests.

[0026] Furthermore, the variation characteristics include: any one or more of variation rate, variation thickness, pump valve flow deviation, jamming, pipeline flow resistance, heat transfer of heat exchange equipment, actuator response delay, and blade damage.

[0027] According to the difference in the degree of evolution, a linear model family of the control subsystem with corresponding degree of evolution is established. A control subsystem includes one or more devices. A control subsystem corresponds to a subsystem linear model family, which is used to describe the evolution degree of one or more device sets.

[0028] Preferably, the subsystem linear model family is a combination link composed of second-order or lower dynamic links or simple links connected in series or in parallel.

[0029] As a specific embodiment, when the derivative device is a regulating valve, the derivative characteristic is stuck, that is, the response speed is slowed down. According to the difference in the degree of stuckness, the linear model of the control subsystem includes: ; in, Indicates the gain of the dynamic link; Represents the time constant of the dynamic link; represents a complex variable.

[0030] As another embodiment, when the variant device is a water supply pump, the variant feature is blade damage, that is, the water supply capacity becomes weaker. According to the blade damage difference, the linear model of the control subsystem includes: ; in, Indicates the gain of the dynamic link; Represents the time constant of the dynamic link; represents a complex variable.

[0031] It should be noted that if Figure 3 As shown in , the design principle of the controller sequence is to ensure that the poles of the closed-loop control system composed of each controller and the corresponding linear model are distributed in the pole plane area. Figure 4 As shown, the hatched area of ​​the left half plane is the pole plane area.

[0032] Preferably, the poles are distributed in the pole plane area and have the same pole position, so that the overshoot of the controlled quantity does not exceed , thereby ensuring the stable operation of the controlled subsystem; at the same time, the rise time is not greater than , ensuring that the dynamic response of the output of the controlled subsystem is fast enough.

[0033] For example, Figure 4 As shown, the damping ratio Take 0.7, the overshoot of water flow rate (controlled quantity) No more than 5%, to ensure the smooth operation of the water supply system of the nuclear power plant; natural damping frequency Take 0.6, the water flow rate rise time under variable working conditions No more than 3 seconds to ensure a fast enough dynamic response process.

[0034] Step 103: Input the current input information into the control subsystem and the subsystem linear model family respectively, and obtain the physical output of the control subsystem and the model output of the subsystem linear model family accordingly.

[0035] Specifically, if Figure 5 As shown, the current input information (control amount ) acts on the control subsystem, that is, the regulating valve opening acts on the water supply system and measures the physical output ; At the same time, the current input information (control amount ) acts on the linear model family, that is, the control valve opening is also used as the control quantity Input the linear model family and obtain the calculated value of the water supply flow corresponding to each linear model, which is also the model output. .

[0036] Step 104: obtaining an arbitration vector according to the physical output quantity and the model output quantity; 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.

[0037] As an embodiment, obtaining the arbitration vector includes: subtracting the model output quantity from the physical output quantity actually output by the subsystem linear model family to obtain a deviation vector; and obtaining the arbitration vector based on the deviation vector.

[0038] More specifically, the bias vector for: ;in, ; Represents the model output; Represents the physical output quantity.

[0039] based on The expression of forms the arbitration vector. Specifically, the arbitration vector for: ;in, ; and represents the adjustment coefficient; Indicates the starting time of integration, which is the starting time of variable working conditions; represents the end time of the integration, 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, , .

[0040] Preferably, the best controller is the controller of the subsystem linear model family corresponding to the minimum value in the arbitration vector.

[0041] For example, the minimum rule is used as the arbitrator, that is, the arbitration vector is selected The minimum value in each The linear model corresponding to the minimum value of is the most matching 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 immediately switched to implement control, thereby completing the online switching of multiple controllers.

[0042] On the other hand, the present invention provides a dynamic control system for 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.

[0043] More specifically, the dynamic control system may further include three functional modules: 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, and will not be described one by one here.

[0044] It should be noted that, for the above-mentioned various embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, and according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0045] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. In the several embodiments provided in this application, it should be understood that the disclosed method or system can be implemented in other ways. For example, the embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0046] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0047] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0048] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the whole or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a memory, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application.

[0049] Those skilled in the art will appreciate that all or part of the various circuits in the above embodiments may be completed by entering a program to instruct related hardware, and the program may be stored in a computer-readable memory, which may include: a flash drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0050] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

[0051] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. As long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dynamic control method for a steam power system, characterized in that: The method comprises: Dividing the steam power system into a plurality of control subsystems, and determining input information and output information of the plurality of control subsystems; Establishing multiple subsystem linear model families based on the evolution degree of different control subsystems; and obtaining corresponding controller sequences according to the subsystem linear model families; Inputting the current input information into the control subsystem and the subsystem linear model family respectively, and obtaining the physical output of the control subsystem and the model output of the subsystem linear model family accordingly; An arbitration vector is obtained according to the physical output and the model output; an optimal controller is selected from a controller sequence based on the arbitration vector, and the dynamic control of the steam power system is realized by using the optimal controller.

2. A dynamic control method for a steam power system according to claim 1, characterized in that: The control subsystem is divided according to minimum control units, each of which includes one or more devices.

3. A dynamic control method for a steam power system according to claim 1, characterized in that: The subsystem linear model family is a combination link formed by connecting dynamic links or simple links of the second order or below in series or in parallel.

4. A dynamic control method for a steam power system according to claim 3, characterized in that: The variation degree includes the variation characteristics of the equipment and the variation value corresponding to the variation characteristics.

5. A dynamic control method for a steam power system according to claim 1, characterized in that: The obtaining of the arbitration vector includes: The model output is subtracted from the physical output actually output by the subsystem linear model family to obtain a deviation vector; and an arbitration vector is obtained based on the deviation vector.

6. A dynamic control method for a steam power system according to claim 5, characterized in that: The deviation vector for: ； in, ; Represents the model output; Represents the physical output quantity.

7. A dynamic control method for a steam power system according to claim 6, characterized in that: The arbitration vector for: ； in, ; and represents the adjustment coefficient; Indicates the starting time of integration, which is the starting time of variable working conditions; Indicates the end time of the integration, which is determined by the length of the subsystem's dynamic process.

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

9. A dynamic control method for a steam power system according to claim 4, characterized in that: The variation characteristics include: any one or more of variation rate, variation thickness, pump valve flow deviation, jamming, pipeline flow resistance, heat transfer of heat exchange equipment, actuator response delay, and blade damage.

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

Images