Turbine maintenance cycle decision-making method and system

Abstract

The invention relates to a steam turbine overhaul cycle decision-making method and system, and the method comprises the steps: obtaining the operation parameter data of a steam turbine under all working conditions, and constructing a steam turbine dissipation temperature database; calculating dissipation temperatures of different parts in the steam turbine in real time; determining the current health condition of the steam turbine based on the dissipation temperature of the steam turbine under the full working condition in the steam turbine dissipation temperature database and the dissipation temperature calculated in real time; and the safety coefficient and the economical efficiency coefficient of the steam turbine under the current health condition are calculated respectively, and whether the steam turbine needs to be maintained or not is determined based on the safety coefficient and the economical efficiency coefficient. According to the method and the device, the current health condition of the steam turbine component is mastered in real time based on the constructed steam turbine dissipation temperature database and the dissipation temperature calculated in real time, and the maintenance period of the steam turbine under the current health condition is further determined from the two dimensions of safety and economy; the problem of how to reasonably determine the overhaul period of the steam turbine is solved.

Description

Technical Field

[0001] The present application relates to the field of maintenance of power equipment, and particularly to a method and system for making decisions on the maintenance cycle of a steam turbine. Background Art

[0002] As a key equipment of a thermal power unit, the safe and economic operation of a steam turbine is crucial for the unit. Among them, the steam turbine rotor is in a harsh condition of high temperature and high pressure for a long time, and the rotor life basically represents the life of the whole unit. The life loss of the steam turbine rotor is mainly caused by low-cycle fatigue loss due to thermal stress generated during the process of changing operating conditions. During the actual operation process, the performance of the components of the steam turbine will degrade due to long-term operation, and after degradation, the operating parameters will change, thereby affecting the rotor life. Therefore, how to reasonably determine the maintenance cycle of the steam turbine is an urgent problem to be solved at present.

[0003] At present, for the problem of how to reasonably determine the maintenance cycle of a steam turbine in the related art, no effective solution has been proposed. Summary of the Invention

[0004] Embodiments of the present application provide a method and system for making decisions on the maintenance cycle of a steam turbine, so as to at least solve the problem of how to reasonably determine the maintenance cycle of a steam turbine in the related art.

[0005] In a first aspect, embodiments of the present application provide a method for making decisions on the maintenance cycle of a steam turbine, and the method includes:

[0006] Obtain the operating parameter data of the steam turbine under full operating conditions, and based on the operating parameter data, construct a steam turbine dissipation temperature database;

[0007] Calculate the dissipation temperature of different components in the steam turbine in real time;

[0008] Based on the dissipation temperature of the steam turbine under full operating conditions in the steam turbine dissipation temperature database and the dissipation temperature calculated in real time, determine the current health status of the steam turbine;

[0009] Calculate the safety factor and economic factor of the steam turbine under the current health status respectively, and based on the safety factor and economic factor, determine whether the steam turbine needs to be repaired.

[0010] In some of these embodiments, calculating the safety factor of the steam turbine under the current health status includes:

[0011] Calculate the rotor temperature field of the steam turbine by the finite difference method;

[0012] Based on the rotor temperature field, the rotor thermal stress of the steam turbine is calculated, and the low-cycle fatigue life of the steam turbine rotor is obtained based on the rotor thermal stress. The low-cycle fatigue life is used as the safety factor of the steam turbine under the current health condition.

[0013] In some embodiments, calculating the rotor temperature field of the steam turbine by the finite difference method includes:

[0014] Determine the first boundary condition of the finite difference method where T is the rotor temperature, τ is the time, r is the radius, and α is the thermal diffusivity; when r = R i , R i is the radius of the central hole, and the first boundary condition is used to characterize the adiabatic performance of the central hole of the rotor of the steam turbine;

[0015] Determine the second boundary condition of the finite difference method where h is the convective surface heat transfer coefficient, T st is the steam temperature at the cross-section, T s is the rotor surface temperature, λ is the thermal conductivity, R0 is the rotor radius, and the second boundary condition is used to characterize the rotor surface temperature of the steam turbine;

[0016] Under the first boundary condition and the second boundary condition, the rotor temperature field of the steam turbine is calculated by the finite difference method.

[0017] In some embodiments, calculating the rotor thermal stress of the steam turbine based on the rotor temperature field includes:

[0018] Based on the rotor temperature field, through the thermal stress calculation formula:

[0019]

[0020] Calculate the rotor thermal stress of the steam turbine, where E is the elastic modulus of the rotor material, β is the linear expansion coefficient of the rotor material, υ is the Poisson's ratio of the rotor material; K th is the thermal stress concentration coefficient considering the rotor structure; △t m is the volume average temperature t m of the rotor and the difference between the inner and outer surfaces.

[0021] In some embodiments, obtaining the low-cycle fatigue life of the steam turbine rotor based on the rotor thermal stress includes:

[0022] Based on the rotor thermal stress and the fatigue curve of the steam turbine, the load is processed by the rainflow method to obtain the low-cycle fatigue life of the steam turbine rotor.

[0023] In some of these embodiments, calculating the economic coefficient of the steam turbine under the current health condition includes:

[0024] Calculating the additional fuel consumption expenditure of the steam turbine under the current health condition compared to the steam turbine in a completely healthy state, and calculating the overhaul expenditure for the steam turbine to return to the completely healthy state under the current health condition;

[0025] Taking the additional fuel consumption expenditure and the overhaul expenditure as the economic coefficient of the steam turbine under the current health condition.

[0026] In some of these embodiments, determining whether the steam turbine needs maintenance based on the safety coefficient and the economic coefficient includes:

[0027] Judging whether the low-cycle fatigue life as the safety coefficient is greater than zero, and at the same time judging whether the additional fuel consumption expenditure as the economic coefficient is greater than the overhaul expenditure;

[0028] If the low-cycle fatigue life is greater than zero and the additional fuel consumption expenditure is not greater than the overhaul expenditure, then the steam turbine does not need maintenance;

[0029] If the low-cycle fatigue life is not greater than zero and the additional fuel consumption expenditure is greater than the overhaul expenditure, then the steam turbine needs maintenance;

[0030] If the low-cycle fatigue life is not greater than zero or the additional fuel consumption expenditure is greater than the overhaul expenditure, then the steam turbine needs maintenance.

[0031] In some of these embodiments, obtaining the operating parameter data of the steam turbine under full operating conditions and constructing a steam turbine dissipation temperature database based on the operating parameter data includes:

[0032] Constructing a full operating condition simulation model of the steam turbine and simulating the work process through the full operating condition simulation model of the steam turbine;

[0033] In the work process simulation, selecting the dissipation temperature defined by the second law of thermodynamics as the first operating parameter of different components of the steam turbine under full operating conditions, where the first operating parameter is used to characterize the performance of different components in the steam turbine;

[0034] In the work process simulation, selecting the dissipation temperature of steam turbines in different health conditions under full operating conditions as the second operating parameter;

[0035] Constructing a steam turbine dissipation temperature database based on the data corresponding to the first operating parameter and the second operating parameter.

[0036] In some of these embodiments, calculating the dissipated temperatures of different components in the steam turbine in real time includes:

[0037] Arranging temperature measurement points and pressure measurement points at the inlets and outlets of the high-pressure cylinder, the medium-pressure cylinder, and the low-pressure cylinder of the steam turbine respectively;

[0038] Based on the data collected in real time by the temperature measurement points and the pressure measurement points, calculating the dissipated temperatures of different components.

[0039] In a second aspect, an embodiment of the present application provides a decision-making system for the maintenance cycle of a steam turbine. The system is used to execute the method described in the first aspect above. The system includes a database construction module, a real-time data acquisition module, and a maintenance decision-making module;

[0040] The database construction module is used to obtain the operating parameter data of the steam turbine under full operating conditions and construct a steam turbine dissipated temperature database based on the operating parameter data;

[0041] The real-time data acquisition module is used to calculate the dissipated temperatures of different components in the steam turbine in real time;

[0042] The maintenance decision-making module is used to determine the current health status of the steam turbine according to the dissipated temperatures of the steam turbine under full operating conditions in the steam turbine dissipated temperature database and the dissipated temperatures calculated in real time;

[0043] The maintenance decision-making module is used to calculate the safety coefficient and the economic coefficient of the steam turbine under the current health status respectively, and determine whether the steam turbine needs to be repaired based on the safety coefficient and the economic coefficient.

[0044] Compared with the related art, an embodiment of the present application provides a method and a system for decision-making on the maintenance cycle of a steam turbine. Among them, the method constructs a steam turbine dissipated temperature database by obtaining the operating parameter data of the steam turbine under full operating conditions and based on the operating parameter data; calculates the dissipated temperatures of different components in the steam turbine in real time; determines the current health status of the steam turbine based on the dissipated temperatures of the steam turbine under full operating conditions in the steam turbine dissipated temperature database and the dissipated temperatures calculated in real time; calculates the safety coefficient and the economic coefficient of the steam turbine under the current health status respectively, and determines whether the steam turbine needs to be repaired based on the safety coefficient and the economic coefficient, realizing real-time mastery of the current health status of the steam turbine components based on the constructed steam turbine dissipated temperature database and the dissipated temperatures calculated in real time, and further determining the maintenance cycle of the steam turbine under the current health status from two dimensions of safety and economy, and solving the problem of how to reasonably determine the maintenance cycle of the steam turbine. Description of the Drawings

[0045] The accompanying drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0046] Figure 1 is a flowchart of the steps of the steam turbine overhaul cycle decision-making method according to an embodiment of the present application;

[0047] Figure 2 is a schematic diagram of the process of the steam turbine overhaul cycle decision-making method according to an embodiment of the present application;

[0048] Figure 3 is a schematic internal structure diagram of an electronic device according to an embodiment of the present application. Detailed implementation manners

[0049] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be described and explained 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 application and are not used to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0050] Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without making creative efforts, the present application can also be applied to other similar scenarios based on these drawings. In addition, it can also be understood that although the efforts made in this development process may be complex and time-consuming, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacturing or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be understood as insufficient disclosure of the content of the present application.

[0051] Referring to "embodiment" in the present application means that a specific feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those of ordinary skill in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments without conflict.

[0052] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the ordinary meanings understood by those with ordinary skills in the technical field to which this application belongs. The words such as "a", "an", "one", "the" and the like involved in this application do not indicate a limitation of quantity and may represent a singular or plural number. The terms "comprising", "including", "having" and any variations thereof involved in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or units, but may further include unlisted steps or units, or may further include other steps or units inherent to these processes, methods, products or devices. The similar words such as "connected", "coupled" and "joined" involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "plurality" involved in this application means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, "A and / or B" may represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after. The terms "first", "second", "third" and the like involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0053] An embodiment of this application provides a decision-making method for the overhaul cycle of a steam turbine. Figure 1 It is a step flow chart of the decision-making method for the overhaul cycle of a steam turbine according to the embodiment of this application, as Figure 1 shown, and this method includes the following steps:

[0054] Step S102: Obtain the operation parameter data of the steam turbine under full operating conditions, and based on the operation parameter data, construct a steam turbine dissipation temperature database.

[0055] Step S102 specifically includes the following steps:

[0056] Step S1021: Construct a full operating condition simulation model of the steam turbine, and simulate the work process through the full operating condition simulation model of the steam turbine.

[0057] It should be noted that the simulation model is a model that can simulate the behavior of the system established by fitting and calibrating the data of the actual system, and this kind of model is usually data-driven (such as statistical models, machine learning models, etc.). In step S1021, by simulating the work process through the full operating condition simulation model of the steam turbine, the working medium values and working medium entropy values at the inlets and outlets of different components of the steam turbine are obtained.

[0058] Step S1022, in the workflow simulation, select the dissipation temperature defined by the second law of thermodynamics as the first operating parameter of different components of the steam turbine under full operating conditions, where the first operating parameter is used to characterize the performance of different components in the steam turbine;

[0059] Specifically in step S1022, select the dissipation temperature defined based on the second law of thermodynamics as an index to characterize the performance of different components in the steam turbine, and its specific calculation formula is:

[0060] ζ = (e in,k - e out,k ) / (S in,k - S out,k )

[0061] where e in,k is the inlet working fluid of component k e out,k is the outlet working fluid of component k S in,k is the entropy of the inlet working fluid of component k, and S out,k is the entropy of the outlet working fluid of component k.

[0062] Step S1023, in the workflow simulation, select the dissipation temperatures of steam turbines in different health conditions under full operating conditions as the second operating parameter;

[0063] Step S1024, construct a steam turbine dissipation temperature database based on the data corresponding to the first operating parameter and the second operating parameter.

[0064] Step S104, calculate the dissipation temperatures of different components in the steam turbine in real time;

[0065] Specifically in step S104, arrange temperature measurement points and pressure measurement points at the inlets and outlets of the high-pressure cylinder, the medium-pressure cylinder, and the low-pressure cylinder of the steam turbine respectively; calculate the dissipation temperatures of different components based on the data collected in real time by the temperature measurement points and the pressure measurement points.

[0066] Step S106, determine the current health condition of the steam turbine based on the dissipation temperature of the steam turbine under full operating conditions in the steam turbine dissipation temperature database and the dissipation temperature calculated in real time;

[0067] Step S108, calculate the safety coefficient and the economic coefficient of the steam turbine under the current health condition respectively, and determine whether the steam turbine needs to be repaired based on the safety coefficient and the economic coefficient.

[0068] Step S108 specifically includes the following steps:

[0069] Step S1081, calculate the rotor temperature field of the steam turbine by the finite difference method;

[0070] Specifically for step S1081:

[0071] Determine the first boundary condition of the finite difference method where T is the rotor temperature (unit: °C), τ is the time (unit: s), r is the radius (unit: m), and α is the thermal diffusivity (unit: m 2 / s); when r = R i , R i is the radius of the central hole, and the first boundary condition is used to characterize the adiabatic performance of the central hole of the steam turbine rotor;

[0072] Determine the second boundary condition of the finite difference method where h is the convective surface heat transfer coefficient (unit: W / (m 2 ·K)), T st is the steam temperature at the cross-section (unit: °C), T s is the rotor surface temperature (unit: °C), λ is the thermal conductivity (unit: W / (m·K)), R0 is the rotor radius (unit: m), and the second boundary condition is used to characterize the rotor surface temperature of the steam turbine;

[0073] Under the first boundary condition and the second boundary condition, the rotor temperature field of the steam turbine is calculated by the finite difference method.

[0074] In step S1082, based on the rotor temperature field, calculate the rotor thermal stress of the steam turbine, and based on the rotor thermal stress, obtain the low-cycle fatigue life of the steam turbine rotor, and use the low-cycle fatigue life as the safety factor of the steam turbine under the current health condition.

[0075] Specifically for step S1082:

[0076] Based on the rotor temperature field, through the thermal stress calculation formula:

[0077]

[0078] calculate the rotor thermal stress of the steam turbine, where E is the elastic modulus of the rotor material (unit: Mpa), β is the linear expansion coefficient of the rotor material, υ is the Poisson's ratio of the rotor material; K th is the thermal stress concentration coefficient considering the rotor structure; △t m is the difference between the volume average temperature t m of the rotor and the inner and outer surfaces (unit: °C).

[0079] Based on the rotor thermal stress and the fatigue curve of the steam turbine, process the load by the rainflow method to obtain the low-cycle fatigue life of the steam turbine rotor.

[0080] Step S1083: Calculate the additional fuel consumption expenditure of the steam turbine under the current health condition compared to that under the completely healthy condition, and calculate the overhaul expenditure for the steam turbine to be restored to the completely healthy condition from the current health condition; use the additional fuel consumption expenditure and the overhaul expenditure as the economic coefficient of the steam turbine under the current health condition.

[0081] It should be noted that the additional fuel consumption expenditure and the overhaul expenditure in Step S1083 can be calculated through the full-condition simulation model of the steam turbine, so as to compare the additional fuel expenditure and the overhaul expenditure, and analyze from the economic perspective whether the steam turbine needs to be overhauled. The specific calculation is as follows:

[0082] The overhaul cost includes: the direct overhaul cost per unit electricity and the power generation loss during overhaul per unit electricity.

[0083] Direct overhaul cost per unit electricity: CHM1 = A / (P e *P T *N*X), where A is the total overhaul cost of the steam turbine components, P e is the power of the steam turbine, P T is the overhaul time interval, N is the annual operating hours, and X is the average load factor.

[0084] Power generation loss during overhaul per unit electricity: CHM2 = 24 * T m *D / (P T *N), where T m is the maintenance time, and D is the electricity price (unit: ￥ / kWh).

[0085] Additional fuel consumption cost: fuel price (unit: yuan / Nm 3 ) * additional fuel consumption (unit: Nm 3 / kwh).

[0086] Step S1084 Figure 2 is a schematic flowchart of the steam turbine overhaul cycle decision method according to an embodiment of the present application. As Figure 2 shown, judge whether the low-cycle fatigue life as the safety coefficient is greater than zero, and at the same time judge whether the additional fuel consumption expenditure as the economic coefficient is greater than the overhaul expenditure; ① If the low-cycle fatigue life is greater than zero and the additional fuel consumption expenditure is not greater than the overhaul expenditure, the steam turbine does not need to be repaired; ② If the low-cycle fatigue life is not greater than zero and the additional fuel consumption expenditure is greater than the overhaul expenditure, the steam turbine needs to be repaired; ③ If the low-cycle fatigue life is not greater than zero and the additional fuel consumption expenditure is not greater than the overhaul expenditure, the steam turbine needs to be repaired; ④ If the low-cycle fatigue life is greater than zero and the additional fuel consumption expenditure is greater than the overhaul expenditure, the steam turbine needs to be repaired.

[0087] It should be noted that, by comparing the additional fuel consumption of the steam turbine due to its health condition under the same load, the additional fuel consumption expenditure and the maintenance expenditure of the steam turbine under the current health condition are compared, and whether the steam turbine needs to be maintained is analyzed from the economic perspective. That is, when the additional fuel consumption expenditure ≤ the maintenance expenditure, from the economic perspective, the component can continue to operate; when the additional fuel consumption expenditure > the maintenance expenditure, from the economic perspective, the component must be maintained.

[0088] Furthermore, it should be noted that the embodiment of the present application provides a method for making a decision on the maintenance cycle of a steam turbine. By measuring the inlet and outlet parameters of the component, the dissipated temperature value based on the analysis method is calculated, and the component efficiency is characterized by the dissipated temperature to monitor the health condition of the steam turbine components in real time. ① From the perspective of safety, the temperature and pressure of the working medium are monitored in real time, and the service life of each component of the steam turbine is calculated online to obtain a more reasonable maintenance cycle. ② From the economic perspective, according to the health condition of the component, the additional fuel consumption of the steam turbine component under the current health condition is obtained, and the additional fuel expenditure is compared with the maintenance expenditure to reduce the occurrence of excessive maintenance. In other words, on the one hand, the embodiment of the present application analyzes the remaining life of the rotor from the safety perspective to make a maintenance decision; on the other hand, it compares the additional fuel expenditure caused by the state decay of the steam turbine with the maintenance expenditure from the economic perspective to make a maintenance decision, and a more reasonable maintenance time is obtained by combining safety and economy.

[0089] Through the above steps in the embodiment of the present application, based on the constructed dissipated temperature database of the steam turbine and the dissipated temperature calculated in real time, the current health condition of the steam turbine components is grasped in real time, and further, the maintenance cycle of the steam turbine under the current health condition is determined from two dimensions of safety and economy, solving the problem of how to reasonably determine the maintenance cycle of the steam turbine.

[0090] It should be noted that the steps shown in the above process or the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0091] The embodiment of the present application provides a steam turbine maintenance cycle decision-making system, which includes a database construction module, a real-time data acquisition module, and a maintenance decision-making module;

[0092] The database construction module is used to obtain the operation parameter data of the steam turbine under full operating conditions and construct a dissipated temperature database of the steam turbine based on the operation parameter data;

[0093] The real-time data acquisition module is used to calculate the dissipated temperature of different components in the steam turbine in real time;

[0094] An overhaul decision-making module, configured to determine the current health status of the steam turbine according to the dissipated temperature of the steam turbine under all operating conditions in the steam turbine dissipated temperature database and the dissipated temperature calculated in real time;

[0095] The overhaul decision-making module is configured to calculate respectively the safety factor and the economic factor of the steam turbine under the current health status, and determine whether the steam turbine needs to be repaired based on the safety factor and the economic factor.

[0096] Through the database construction module, the real-time data acquisition module and the overhaul decision-making module in the embodiments of the present application, it is realized to master in real time the current health status of the steam turbine components based on the constructed steam turbine dissipated temperature database and the dissipated temperature calculated in real time, and further determine the overhaul period of the steam turbine under the current health status from two dimensions of safety and economy, solving the problem of how to reasonably determine the overhaul period of the steam turbine.

[0097] It should be noted that the above-mentioned each module can be a functional module or a program module, and can be implemented either by software or by hardware. For the modules implemented by hardware, the above-mentioned each module can be located in the same processor; or the above-mentioned each module can also be located in different processors in any combined form.

[0098] This embodiment also provides an electronic device, including a memory and a processor, where a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0099] Optionally, the above-mentioned electronic device may further include a transmission device and an input / output device, where the transmission device is connected to the above-mentioned processor, and the input / output device is connected to the above-mentioned processor.

[0100] It should be noted that the specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation manners, and will not be repeated here.

[0101] In addition, in combination with the steam turbine overhaul period decision-making method in the above embodiments, the embodiments of the present application can be implemented by providing a storage medium. A computer program is stored on the storage medium; when the computer program is executed by a processor, it implements any one of the steam turbine overhaul period decision-making methods in the above embodiments.

[0102] In one embodiment, a computer device is provided, and the computer device may be a terminal. The computer device includes a processor, a memory, a network interface, a display screen, and an input device connected through a system bus. 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 network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements a method for making a decision on the maintenance cycle of a steam turbine. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device may be a touch layer covering the display screen, or a button, a trackball, or a touchpad provided on the housing of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0103] In one embodiment, Figure 3 is a schematic internal structure diagram of an electronic device according to an embodiment of the present application, as Figure 3 shown, an electronic device is provided, and the electronic device may be a server, and its internal structure diagram may be as Figure 3 shown. The electronic device includes a processor, a network interface, an internal memory, and a non-volatile memory connected through an internal bus. Among them, the non-volatile memory stores an operating system, a computer program, and a database. The processor is used to provide computing and control capabilities. The network interface is used to communicate with an external terminal through a network connection. The internal memory is used to provide an environment for the operation of the operating system and the computer program. When the computer program is executed by the processor, it implements a method for making a decision on the maintenance cycle of a steam turbine. The database is used to store data.

[0104] Those skilled in the art can understand that Figure 3 the structure shown in

[0105] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. This computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the embodiments provided in the present application can include non-volatile and / or volatile memories. Non-volatile memories can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memories can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0106] Those skilled in the art should understand that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered as the scope described in this specification.

[0107] The above embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for determining a steam turbine maintenance cycle, characterized in that: The method comprises: Acquire operating parameter data of the steam turbine under all operating conditions, and construct a steam turbine dissipation temperature database based on the operating parameter data; Calculating the dissipated temperature of different components in the steam turbine in real time; Determining the current health status of the steam turbine based on the dissipation temperature of the steam turbine under all operating conditions in the steam turbine dissipation temperature database and the real-time calculated dissipation temperature; The safety factor and the economic factor of the steam turbine under the current health status are calculated respectively, and based on the safety factor and the economic factor, it is determined whether the steam turbine needs to be repaired.

2. The method according to claim 1, characterized in that: Calculating the safety factor of the steam turbine under the current health condition includes: The rotor temperature field of the steam turbine is obtained by calculating the finite difference method; Based on the rotor temperature field, the rotor thermal stress of the steam turbine is calculated, and based on the rotor thermal stress, the low cycle fatigue life of the steam turbine rotor is obtained, and the low cycle fatigue life is used as the safety factor of the steam turbine under the current health status.

3. The method according to claim 2, characterized in that The rotor temperature field of the steam turbine calculated by the finite difference method includes: Determine the first boundary condition for the finite difference method Where T is the rotor temperature, τ is the time, r is the radius, and α is the thermal diffusivity; when r = R i , R i is the radius of the center hole, and the first boundary condition is used to characterize the thermal insulation performance of the rotor center hole of the steam turbine; Determine the second boundary condition of the finite difference method Where h is the convective surface heat transfer coefficient, T st is the steam temperature at the cross section, T s is the rotor surface temperature, λ is the thermal conductivity, R0 is the rotor radius, and the second boundary condition is used to characterize the rotor surface temperature of the steam turbine; Under the first boundary condition and the second boundary condition, the rotor temperature field of the steam turbine is calculated by the finite difference method.

4. The method according to claim 2, characterized in that: Based on the rotor temperature field, the rotor thermal stress of the steam turbine is calculated including: Based on the rotor temperature field, the thermal stress is calculated by the formula: The rotor thermal stress of the steam turbine is calculated, wherein E is the elastic modulus of the rotor material, β is the linear expansion coefficient of the rotor material, and υ is the Poisson's ratio of the rotor material; K th is the thermal stress concentration factor of the rotor structure; △t m is the volume average temperature of the rotor t m The difference between the inner and outer surfaces.

5. The method according to claim 2, characterized in that: The low cycle fatigue life of the steam turbine rotor obtained based on the rotor thermal stress includes: Based on the rotor thermal stress and the fatigue curve of the steam turbine, the load is processed by the rain flow method to obtain the low cycle fatigue life of the steam turbine rotor.

6. The method according to claim 2, characterized in that Calculation of the economic coefficient of the steam turbine under the current health condition includes: Calculate the additional fuel consumption expenditure of the steam turbine in the current health state compared to the steam turbine in the fully healthy state, and calculate the maintenance expenditure of the steam turbine in the current health state to restore the steam turbine to the fully healthy state; The additional fuel consumption expenditure and the maintenance expenditure are used as the economic coefficient of the steam turbine under the current health condition.

7. The method according to claim 6, characterized in that Based on the safety factor and the economic factor, determining whether the steam turbine needs to be repaired includes: Determine whether the low cycle fatigue life as a safety factor is greater than zero, and determine whether the additional fuel consumption expenditure as an economic coefficient is greater than the maintenance expenditure; If the low cycle fatigue life is greater than zero and the additional fuel consumption expenditure is not greater than the maintenance expenditure, then the steam turbine does not need to be repaired; If the low cycle fatigue life is not greater than zero, and the additional fuel consumption expenditure is greater than the maintenance expenditure, the steam turbine needs to be repaired; If the low cycle fatigue life is not greater than zero, or the additional fuel consumption expenditure is greater than the maintenance expenditure, the steam turbine needs to be repaired.

8. The method according to claim 1, characterized in that Acquiring the operating parameter data of the steam turbine under all operating conditions, and constructing a steam turbine dissipation temperature database based on the operating parameter data includes: Constructing a full-operating-condition simulation model of a steam turbine, and simulating a work process through the full-operating-condition simulation model of the steam turbine; In the workflow simulation, the dissipation temperature defined by the second law of thermodynamics is selected as the first operating parameter of different components of the steam turbine under all operating conditions, wherein the first operating parameter is used to characterize the performance of different components in the steam turbine; In the workflow simulation, the dissipation temperature of the steam turbine in different health conditions under all operating conditions is selected as the second operating parameter; A steam turbine dissipation temperature database is constructed based on data corresponding to the first operating parameter and the second operating parameter.

9. The method according to claim 1, characterized in that: Real-time calculation of the dissipated temperature of different components in the steam turbine includes: Temperature measuring points and pressure measuring points are arranged at the inlet and outlet of the high-pressure cylinder, the inlet and outlet of the medium-pressure cylinder and the inlet and outlet of the low-pressure cylinder of the steam turbine respectively; Based on the data collected in real time from the temperature measuring points and the pressure measuring points, the dissipated temperatures of different components are calculated.

10. A steam turbine maintenance cycle decision system, characterized in that: The system is used to execute the method described in any one of claims 1 to 9, and the system includes a database construction module, a real-time data acquisition module and a maintenance decision module; The database construction module is used to obtain the operating parameter data of the steam turbine under all working conditions, and to construct a steam turbine dissipation temperature database based on the operating parameter data; The real-time data acquisition module is used to calculate the dissipated temperature of different components in the steam turbine in real time; The maintenance decision module is used to determine the current health status of the steam turbine according to the dissipation temperature of the steam turbine under all working conditions in the steam turbine dissipation temperature database and the real-time calculated dissipation temperature; The maintenance decision module is used to respectively calculate the safety factor and the economic factor of the steam turbine under the current health status, and determine whether the steam turbine needs maintenance based on the safety factor and the economic factor.

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