Fault detection method for time delay compensation of all-digital networked control system

Abstract

The invention relates to the technical field of operation control of a nuclear power station, and discloses a fault detection method for time delay compensation of an all-digital networked control system, computer equipment, a computer readable storage medium and a computer program product in order to solve the problem that a system fault detection result is inaccurate due to output time delay of a control system of a condensate water system. The method comprises the following steps: step 101, establishing a control object model of the nuclear power station condensate water system; step 102, discretizing the control object model according to a sampling period; step 103, based on the discretized control object model, establishing an observer with a time delay compensation function; step 104, analyzing the observer; step 105, solving a linear matrix inequality to obtain an observer gain matrix; step 106, defining an observer state estimation error, and analyzing to obtain an observer output error; and step 107, according to the observer output error, determining whether the nuclear power station condensate water system has a fault. By adopting the method, the accuracy of a fault detection result can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of operation control of nuclear power plants, and more specifically, to a fault detection method for delay compensation of a fully digital networked control system, a computer device, a computer-readable storage medium, and a computer program product. Background Art

[0002] The integrated control system of a nuclear power plant can complete tasks such as starting, running, and stopping of nuclear power plant equipment. Currently, nuclear power plant equipment has initially realized informatization, networking, and intelligence. Therefore, it is necessary to conduct research on networked control technology for key subsystems of nuclear power plant equipment.

[0003] At present, the method of fixed output delay can make the original network control system equivalent to a short-delay system, which facilitates the design of the fault observer and simplifies the stability proof process of the error system. However, it is also equivalent to artificially expanding the sampling period, so there is a defect that the fault detection result is relatively delayed. Summary of the invention

[0004] In order to solve the problem that the output delay of the control system of the condensate system of a nuclear power plant leads to inaccurate system fault detection results, the present invention provides a fault detection method, computer equipment, computer-readable storage medium and computer program product for time delay compensation of a fully digital networked control system. By performing fault detection on the condensate system with an observer with a delay compensation function, the accuracy of the fault detection results can be improved.

[0005] To achieve the above object, according to a first aspect of the present invention, a fault detection method for time delay compensation of a fully digital networked control system is provided, the method comprising:

[0006] Step 101, establish a control object model of the condensate system of a nuclear power plant:

[0007]

[0008] In the formula, A f is the system state matrix, B f is the system input matrix, C f is the system output matrix, x(t) is the system state vector, v(t) is the system input vector, f(t) is the system fault vector, is the rate of change of the system state vector, y(t) is the system output vector;

[0009] Step 102, discretize the control object model according to the sampling period T, and obtain:

[0010]

[0011] Where A is the discretized system state matrix, and its value is B is the discretized system input matrix, and its value is C is the discretized system output matrix, and its value is C f ;x k is the system state vector at time k after discretization, u k is the system input vector at time k after discretization, f k is the system fault vector at time k after discretization, x k+1 is the system state vector at time k+1 after discretization, y k+1 is the system output vector at time k+1 after discretization;

[0012] Step 103: Based on the discretized control object model, an observer with a delay compensation function is established. The observer is:

[0013]

[0014] In the formula, is the output delay, which is an integer multiple of the sampling period T and has an upper bound of is the system state vector estimated by the observer at time k, is the observer gain matrix, After discretization The system output vector at time , The observer estimates The system output vector at time , is the system state vector at time k+1 estimated by the observer;

[0015] Step 104, analyze the observer and obtain:

[0016]

[0017] Step 105, define the observer gain matrix as:

[0018]

[0019] Solve the linear matrix inequality to obtain P and The linear matrix inequality is:

[0020]

[0021] According to P. And formula (8), we get the observer gain matrix;

[0022] Step 106, define the observer state estimation error as:

[0023]

[0024] Substituting the observer gain matrix into formula (6), according to formula (2), formula (6) and formula (7), we get:

[0025]

[0026] Where H is the observer output weight matrix, ε k is the observer output error;

[0027] Step 107: Determine whether a condensate system of the nuclear power plant fails based on the observer output error.

[0028] Furthermore, in the above step 107, whether a fault occurs in the condensate system of the nuclear power plant according to the observer output error is determined, including determining that the condensate system of the nuclear power plant has not failed when the absolute value of the observer output error is not greater than the error threshold; and determining that a fault occurs in the condensate system of the nuclear power plant when the absolute value of the observer output error is greater than the error threshold.

[0029] Furthermore, the above-mentioned fault detection method for time delay compensation of the fully digital networked control system also includes determining an error threshold value according to the operation status of the condensate system of the nuclear power plant.

[0030] Furthermore, in the above step 104, the observer is analyzed to obtain formula (6), including:

[0031] From formula (2), we can get:

[0032]

[0033] Depend on get:

[0034]

[0035] Substituting formula (5) into formula (3), we get:

[0036]

[0037] Furthermore, x(t)∈R n , v(t)∈R n , y(t)∈R l , R n represents an n-dimensional vector space, R l represents an l-dimensional vector space.

[0038] Furthermore, when the condensing water system works normally, f(t) is a zero vector; when a failure occurs in the condensing water system, f(t) is a non-zero vector.

[0039] Furthermore, when the condensate system works normally, formula (10) is transformed to obtain:

[0040]

[0041] According to a second aspect of the present invention, there is also provided a computer device, which includes a memory, a processor and a computer program stored in the memory, and the processor executes the computer program to implement the steps of any one of the above methods.

[0042] According to a third aspect of the present invention, there is also provided a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of any of the above methods are implemented.

[0043] According to a fourth aspect of the present invention, there is also provided a computer program product, comprising a computer program, which implements the steps of any of the above methods when executed by a processor.

[0044] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0045] The present invention provides a fault detection method for time delay compensation of a fully digital networked control system. The method targets the output delay of the control system of a condensate water system of a nuclear power plant, performs fault detection on the condensate water system through an observer with a time delay compensation function, and does not affect the sampling period of the original condensate water system. Therefore, the accuracy of the fault detection result can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 A structural block diagram of a nuclear power plant condensate system provided in an embodiment of the present application;

[0048] Figure 2 It is a structural schematic diagram of the control system of the existing nuclear power plant condensate system;

[0049] Figure 3 A flowchart of a fault detection method for time delay compensation in a fully digital networked control system provided in an embodiment of the present application;

[0050] Figure 4AA comparison diagram of an actual state vector of a nuclear power plant condensate system during operation and a state vector estimated by an observer in a case provided in an embodiment of the present application;

[0051] Figure 4B A comparison diagram of an actual state vector of a nuclear power plant condensate system during operation and a state vector estimated by an observer in another case provided in an embodiment of the present application;

[0052] Figure 5 A schematic diagram of a fault detection result provided in an embodiment of the present application;

[0053] Figure 6 A schematic diagram of the internal structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0055] The terms "first", "second", "third", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0056] like Figure 1 As shown, a structural block diagram of a nuclear power plant condensation system is provided. The nuclear power plant condensation system includes a main controller, multiple condensation nodes and condensers. The condensation nodes are composed of condensation pumps and field controllers. The main controller sends control instructions to each condensation node through the control network, and also receives condensation coordination control information from the condenser.

[0057] Figure 2The schematic diagram of the control system structure of the existing nuclear power plant condensate system. The system input vector v(t) is obtained through the actuator, the system output vector y(t) is measured by the sensor, the system output vector y(t) is input into the network for analysis, the discretized system output vector z(t) is output, and the control quantity u(t) at the next moment is output through the controller. Among them, there is a certain delay when the system output vector y(t) is input into the network for analysis, which will cause the fault detection result to be relatively delayed.

[0058] like Figure 3 As shown, a fault detection method for delay compensation of a fully digital networked control system is provided. The method can be executed by a terminal or by a server that communicates with the terminal through a network. The terminal can be, but is not limited to, various personal computers, laptops, smart phones, tablet computers, etc. The server can be an independent server or a server cluster composed of multiple servers. The method is described by taking the application of the method to a terminal as an example, and includes the following steps:

[0059] Step 101, establish a control object model of the condensate system of a nuclear power plant:

[0060]

[0061] In the formula, A f is the system state matrix, B f is the system input matrix, C f is the system output matrix, x(t) is the system state vector, v(t) is the system input vector, f(t) is the system fault vector, is the rate of change of the system state vector, and y(t) is the system output vector.

[0062] Step 102, discretize the control object model according to the sampling period to obtain:

[0063]

[0064] Where A is the discretized system state matrix, and its value is B is the discretized system input matrix, and its value is C is the discretized system output matrix, and its value is C f ;x k is the system state vector at time k after discretization, u k is the system input vector at time k after discretization, f k is the system fault vector at time k after discretization, x k+1 is the system state vector at time k+1 after discretization, y k+1 is the system output vector at time k+1 after discretization.

[0065] Step 103: Based on the discretized control object model, an observer with a delay compensation function is established. The observer is:

[0066]

[0067] In the formula, is the output delay, which is an integer multiple of the sampling period T and has an upper bound of is the system state vector estimated by the observer at time k, is the observer gain matrix, After discretization The system output vector at time , The observer estimates The system output vector at time , is the system state vector at time k+1 estimated by the observer.

[0068] Step 104, analyze the observer and obtain:

[0069]

[0070] Step 105, define the observer gain matrix as:

[0071]

[0072] Solve the linear matrix inequality to obtain P and The linear matrix inequality is:

[0073]

[0074] According to P. And formula (8), we get the observer gain matrix.

[0075] Step 106, define the observer state estimation error as:

[0076]

[0077] Substituting the observer gain matrix into formula (6), according to formula (2), formula (6) and formula (7), we get:

[0078]

[0079] Where H is the observer output weight matrix, ε k is the observer output error.

[0080] Step 107: Determine whether a condensate system of the nuclear power plant fails based on the observer output error.

[0081] The above-mentioned fault detection method of delay compensation for the fully digital networked control system is aimed at the output delay of the control system of the existing nuclear power plant condensate system. Through an observer with a delay compensation function, an observer state estimation error equation is established to perform fault detection on the condensate system. It can detect the occurrence of system faults more quickly, will not increase additional hardware burden, and will not affect the sampling period of the original condensate system. Therefore, it can achieve the purpose of improving the accuracy of fault detection results. By adopting this method, online fault detection and diagnosis can be realized as the control system runs.

[0082] In one embodiment, a fault detection method for time delay compensation of a fully digital networked control system is applied to a condensate system of a nuclear power plant, comprising the following steps:

[0083] Step 1: Establish the control object model of the nuclear power plant condensate system:

[0084]

[0085] In the formula, A f is the system state matrix, B f is the system input matrix, C f is the system output matrix, C f =

[20] ; x(t) is the system state vector, v(t) is the system input vector, f(t) is the system fault vector, is the rate of change of the system state vector, and y(t) is the system output vector.

[0086] Where x(t)∈R n , v(t)∈R n , y(t)∈R l , R n represents an n-dimensional vector space, R l represents an l-dimensional vector space. When the condensate system works normally, f(t) is a zero vector; when the condensate system fails, f(t) is a non-zero vector.

[0087] Step 2: According to the control requirements of the nuclear power plant condensate system, determine the sampling period T = 0.1s; according to the sampling period T, discretize the control object model of the nuclear power plant condensate system to obtain:

[0088]

[0089] Where A is the discretized system state matrix, and its value is B is the discretized system input matrix, C is the discretized system output matrix, and its value is C =

[20] ; x kis the system state vector at time k after discretization, u k is the system input vector at time k after discretization, f k is the system fault vector at time k after discretization, x k+1 is the system state vector at time k+1 after discretization, y k+1 is the system output vector at time k+1 after discretization.

[0090] Step 3, due to Figure 2 The sensor node data packet shown in the figure has a timestamp. Both the sensor and controller nodes are time-driven and the clocks are completely synchronized. The controller obtains the delay information based on the timestamp of the received sensor data and uses the latest sensor data to calculate the control quantity. The output delay of the system must be an integer multiple of the sampling period, that is, the output delay The value of is an integer multiple of the sampling period T, assuming that its upper bound is

[0091] At this time, based on the discretized control object model, an observer with delay compensation function is established, and the observer is:

[0092]

[0093] In the formula, is the output delay, which is an integer multiple of the sampling period T and has an upper bound of is the system state vector estimated by the observer at time k, is the observer gain matrix, After discretization The system output vector at time , The observer estimates The system output vector at time , is the system state vector at time k+1 estimated by the observer.

[0094] Step 4: From formula (2), x k+1 =Ax k +Bu k +f k ,get:

[0095]

[0096] Step 5, by get:

[0097]

[0098] Step 6: Substitute formula (5) into formula (3) to obtain:

[0099]

[0100] Step 7, define the observer state estimation error as:

[0101]

[0102] Figure 4A and Figure 4B This is a comparison chart of the actual state vector of the nuclear power plant condensate system during operation and the state vector estimated by the observer. Figure 4A As shown, before 3s, the actual state vector x1( Figure 4A The solid line in the figure) and the estimated state vector ( Figure 4A There is a certain difference before 3s, but after 3s, the two are almost the same. Figure 4B As shown, during the entire operation, the actual state vector x2 and the estimated state vector Almost the same.

[0103] Step 8: Define the observer gain matrix as:

[0104]

[0105] In the formula,

[0106] Step 9, establish linear matrix inequality:

[0107]

[0108] Using the feasp solver of the LMI toolbox to solve the linear matrix inequality, we get:

[0109]

[0110] According to P. And formula (8), the observer gain matrix is ​​obtained as:

[0111]

[0112] Step 10, substitute the observer gain matrix into formula (6), and according to formula (2), formula (6) and formula (7), we get:

[0113]

[0114] Where H is the observer output weight matrix, and its value is determined according to experience; ε k is the observer output error.

[0115] Step 11, when there is no failure in the condensate system of the nuclear power plant, the formula (10) is transformed to obtain:

[0116]

[0117] Step 12: Determine the error threshold according to the operation of the nuclear power plant condensate system When the absolute value of the observer output error is not greater than the error threshold, it is determined that the nuclear power plant condensate system has not failed; when the absolute value of the observer output error is greater than the error threshold, it is determined that the nuclear power plant condensate system has failed, that is:

[0118]

[0119] Repeat steps 11-12 while the system is running. Figure 5 As shown, Figure 5 This is a schematic diagram of the fault detection results. The horizontal axis represents the time, and the vertical axis represents the observer output error (i.e., the residual value). The error threshold is set to 0.05 ( Figure 5 The horizontal line represented by the dotted line in the figure) is tested and it is found that the output error of the observer first increases and then stabilizes, that is, before 4 seconds, the output error of the observer is less than the error threshold. At this time, it can be determined that the condensate system of the nuclear power plant has no fault; after 4.5 seconds, the output error of the observer is greater than the error threshold. At this time, it can be determined that the condensate system of the nuclear power plant has a fault.

[0120] The present embodiment provides a fault detection method for time delay compensation of a fully digital networked control system, which can perform control on performance control and safety protection, improve the control performance of the condensate system of a nuclear power plant and the accuracy and effectiveness of fault diagnosis, and resolve the contradiction between separation of control and diagnosis.

[0121] The present application also provides a computer device, the internal structure diagram of which can be as follows: Figure 6As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a fault detection method for delay compensation of a fully digital networked control system is implemented.

[0122] Those skilled in the art will understand that Figure 6 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0123] like Figure 6 As shown, the present application also provides a computer device, which includes a memory, a processor, and a computer program stored in the memory, and the processor executes the computer program to implement the steps in the above-mentioned method embodiments.

[0124] The present application also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented. The computer-readable storage medium may include, but is not limited to, any type of disk, including a floppy disk, an optical disk, a DVD, a CD-ROM, a micro drive, and a magneto-optical disk, a ROM, a RAM, an EPROM, an EEPROM, a DRAM, a VRAM, a flash memory device, a magnetic card or an optical card, a nanosystem (including a molecular memory IC), or any type of medium or device suitable for storing instructions and / or data.

[0125] The present application also provides a computer program product, including a computer program, which implements the steps in the above-mentioned method embodiments when executed by a processor.

[0126] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, 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, because 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.

[0127] 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, reference can be made to the relevant descriptions of other embodiments.

[0128] 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 only regarded as exemplary, and the scope and spirit of the present disclosure are defined by the claims.

[0129] 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. However, 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.

[0130] 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 fault detection method for time delay compensation of a fully digital networked control system, characterized in that: Applied to the condensate system of nuclear power plants, including: Step 101, establish a control object model of the condensate system of a nuclear power plant: In the formula, A f is the system state matrix, B f is the system input matrix, C f is the system output matrix, x(t) is the system state vector, v(t) is the system input vector, f(t) is the system fault vector, is the rate of change of the system state vector, y(t) is the system output vector; Step 102: discretize the control object model according to the sampling period T to obtain: Where A is the discretized system state matrix, and its value is B is the discretized system input matrix, and its value is C is the discretized system output matrix, and its value is C f ;x k is the system state vector at time k after discretization, u k is the system input vector at time k after discretization, f k is the system fault vector at time k after discretization, x k+1 is the system state vector at time k+1 after discretization, y k+1 is the system output vector at time k+1 after discretization; Step 103: Based on the discretized control object model, an observer with a delay compensation function is established, and the observer is: In the formula, is the output delay, which is an integer multiple of the sampling period T and has an upper bound of is the system state vector estimated by the observer at time k, is the observer gain matrix, After discretization The system output vector at time , The observer estimates The system output vector at time , is the system state vector at time k+1 estimated by the observer; Step 104, analyzing the observer to obtain: Step 105, define the observer gain matrix as: Solve the linear matrix inequality to obtain P and The linear matrix inequality is: According to P. And formula (8), we get the observer gain matrix; Step 106, define the observer state estimation error as: Substituting the observer gain matrix into formula (6), according to formula (2), formula (6) and formula (7), we obtain: Where H is the observer output weight matrix, ε k is the observer output error; Step 107: Determine whether a condensate system of the nuclear power plant fails based on the observer output error.

2. The method according to claim 1, characterized in that The step 107, determining whether a condensate system of the nuclear power plant fails according to the observer output error, includes: When the absolute value of the observer output error is not greater than the error threshold, it is determined that the nuclear power plant condensate system has not failed; when the absolute value of the observer output error is greater than the error threshold, it is determined that the nuclear power plant condensate system has failed.

3. The method according to claim 2, characterized in that The method further comprises: The error threshold is determined according to the operation status of the condensate system of the nuclear power plant.

4. The method according to claim 1, characterized in that The step 104 is to analyze the observer to obtain formula (6), including: From formula (2), we get: Depend on get: Substituting formula (5) into formula (3), we get:

5. The method according to claim 1, characterized in that x(t)∈R n , v(t)∈R n , y(t)∈R l , R n represents an n-dimensional vector space, R l represents an l-dimensional vector space.

6. The method according to claim 1, characterized in that When the condensate system works normally, f(t) is a zero vector; when the condensate system fails, f(t) is a non-zero vector.

7. The method according to claim 6, characterized in that When the condensate system works normally, the formula (10) is transformed into:

8. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images