A method and apparatus for analyzing cracks in a rotor support

Abstract

The embodiment of the present application provides a rotor support crack analysis method and device, the rotor support crack analysis method comprises the following steps: a generator rotor support model under an operating condition is established; the load of the generator rotor support model is automatically adjusted based on the operating condition, and the stress change of the generator rotor support model under the change of the load is determined; the generator rotor support model is analyzed based on at least the stress change of the generator rotor support model, and the cause of the actual generator rotor support crack is determined. The rotor support crack analysis method of the embodiment of the present application can accurately analyze and determine the cause of the generator rotor support crack according to the actual rotor operation condition, and the process is simple, convenient and easy to implement.

Description

Technical Field

[0001] This invention relates to the field of generator rotor support technology, and in particular to a method and apparatus for crack analysis of rotor supports. Background Technology

[0002] The generator rotor support is a key component connecting the yoke and the shaft, and also a blower element in the ventilation system. During normal operation, the rotor support bears torque, the gravitational torque of the magnetic poles and yoke, its own centrifugal force, and the radial fit force of the hot-forged key. In recent years, cracking problems have appeared in the rotor supports of both vertical and horizontal units. Current research on the cracking problem of rotor supports mainly considers the structural design, material application, processing and manufacturing, and welding factors of the unit rotor support. Through finite element calculation, a rotor support model is established to analyze the stress and deformation of the rotor support at the crack under different operating conditions, including static, rated, and runaway conditions, in order to find out the cause of the crack.

[0003] Rotor supports are components subjected to complex stresses. For some power plant units operating under AGC (Automatic Generation Control) conditions, the load is frequently adjusted, and the stress on the rotor supports changes periodically. In order to comprehensively analyze the causes of rotor support cracks, it is necessary to conduct research on hydraulic, mechanical, electromagnetic and other factors. At present, the research on rotor support crack problems has not yet analyzed the state of the rotor support under the new operating conditions of the unit.

[0004] Rotor supports are components subject to complex stresses. Current research on rotor support cracks mainly focuses on structural design and rigidity, material selection, processing and manufacturing, and welding. However, for new operating conditions with frequent load adjustments, such as AGC automatic power generation control, the actual stress on the rotor support is not considered, making it impossible to accurately determine the causes of rotor support cracks. Summary of the Invention

[0005] This invention provides a simple and easy-to-implement method and apparatus for analyzing cracks in generator rotor supports, which can accurately analyze and determine the causes of cracks in generator rotor supports.

[0006] To address the aforementioned technical problems, embodiments of the present invention provide a crack analysis method for a rotor support, comprising:

[0007] Establish a generator rotor support model under operating conditions;

[0008] The load on the generator rotor support model is automatically adjusted based on the operating conditions, and the stress change of the generator rotor support model under the change of load is determined.

[0009] The generator rotor support model is analyzed based on stress changes to determine the causes that would lead to cracks in the actual generator rotor support.

[0010] As an optional embodiment, the establishment of the generator rotor support model under operating conditions includes:

[0011] Establish a generator rotor support model under the AGC (Automatic Generative Control) operating conditions of a hydropower station.

[0012] As an optional embodiment, it also includes:

[0013] The generator rotor support model is constrained, including constraining the axial and tangential displacements of the mating surface between the rotor support and the main shaft.

[0014] As an optional embodiment, the step of automatically adjusting the load on the generator rotor support model based on operating conditions and determining the stress change of the generator rotor support model under load changes includes:

[0015] The load on the generator rotor support model is automatically adjusted based on the operating conditions.

[0016] At least the stress change of the generator rotor support model during idling and after each load adjustment should be determined.

[0017] As an optional embodiment, it also includes:

[0018] Determine the alternating stress amplitude and the number of cycles of the generator in each cycle of application.

[0019] As an optional embodiment, the analysis of the generator rotor support model based at least on the stress changes of the generator rotor support model to determine the causes that would lead to cracks in the actual generator rotor support includes:

[0020] The generator rotor support model is analyzed based on the stress changes, number of changes, and alternating stress amplitude of the generator in each cycle of application, during idling and after each load adjustment, to determine the causes that would lead to cracks in the actual generator rotor support.

[0021] As an optional embodiment, the analysis of the generator rotor support model based on the stress change, number of changes, and alternating stress amplitude of the generator in each cycle of application during idling and after each load adjustment, to determine the causes that would lead to cracks in the actual generator rotor support, includes:

[0022] Based on the stress changes, number of changes, and alternating stress amplitude of the generator rotor support model during idling and after each load adjustment, at least the cumulative damage and fatigue life of the generator rotor support model should be analyzed to determine the causes that may lead to cracks in the actual generator rotor support.

[0023] Another embodiment of the present invention also provides a crack analysis device for a rotor support, comprising:

[0024] Establish a generator rotor support model under operating conditions;

[0025] The load on the generator rotor support model is automatically adjusted based on the operating conditions, and the stress change of the generator rotor support model under the change of load is determined.

[0026] The generator rotor support model is analyzed based on stress changes to determine the causes that would lead to cracks in the actual generator rotor support.

[0027] As an optional embodiment, it also includes:

[0028] The generator rotor support model is constrained, including constraining the axial and tangential displacements of the mating surface between the rotor support and the main shaft.

[0029] As an optional embodiment, the step of automatically adjusting the load on the generator rotor support model based on operating conditions and determining the stress change of the generator rotor support model under load changes includes:

[0030] The load on the generator rotor support model is automatically adjusted based on the operating conditions.

[0031] At least the stress change of the generator rotor support model during idling and after each load adjustment should be determined.

[0032] Based on the disclosure of the above embodiments, it can be understood that the beneficial effects of the embodiments of the present invention include establishing a model of the generator rotor support under operating conditions, applying different loads that would be borne in real conditions to the model of the generator rotor support using the model, performing simulation operation based on different loads, obtaining various relevant stress data of the rotor support, and finally analyzing the stress data to determine the cause of the rotor support crack.

[0033] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0034] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0035] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the embodiments of the present application to explain the application and do not constitute a limitation thereof. In the drawings:

[0036] Figure 1 This is a flowchart of the crack analysis method for the rotor support in an embodiment of the present invention.

[0037] Figure 2 This is a model diagram of the generator rotor support in an embodiment of the present invention.

[0038] Figure 3 This is a radial deformation distribution diagram of the rotor support in an embodiment of the present invention.

[0039] Figure 4 This is a diagram showing the axial deformation distribution of the rotor support in an embodiment of the present invention.

[0040] Figure 5 This is a stress distribution diagram of the cracked portion 1 of the rotor support in an embodiment of the present invention.

[0041] Figure 6 This is a stress distribution diagram of the cracked portion 2 of the rotor support in an embodiment of the present invention.

[0042] Figure 7 This is a structural block diagram of the crack analysis device for the rotor support in an embodiment of the present invention. Detailed Implementation

[0043] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but these are not intended to limit the scope of the invention.

[0044] It should be understood that various modifications can be made to the embodiments disclosed herein. Therefore, the following description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope and spirit of this disclosure will be apparent to those skilled in the art.

[0045] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present disclosure and, together with the general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure.

[0046] These and other features of the invention will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0047] It should also be understood that although the invention has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of the invention, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0048] The above and other aspects, features and advantages of this disclosure will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0049] Specific embodiments of the present disclosure are described thereafter with reference to the accompanying drawings; however, it should be understood that the disclosed embodiments are merely examples of the present disclosure and can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure the present disclosure. Therefore, the specific structural and functional details disclosed herein are not intended to be limiting, but merely to serve as the basis and representative basis for the claims to teach those skilled in the art to use the present disclosure in a variety of substantially any suitable detailed structures.

[0050] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in still another embodiment,” all of which may refer to one or more of the same or different embodiments according to this disclosure.

[0051] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0052] like Figure 1 As shown, an embodiment of the present invention provides a crack analysis method for a rotor support, comprising:

[0053] Establish a generator rotor support model under operating conditions;

[0054] The load on the generator rotor support model is automatically adjusted based on the operating conditions, and the stress changes of the generator rotor support model under the change of load are determined.

[0055] At least based on the stress changes of the generator rotor support model, the generator rotor support model should be analyzed to determine the causes that would lead to cracks in the actual generator rotor support.

[0056] This embodiment proposes an analysis method for rotor support cracking under AGC (Automatic Generative Control) operation in hydropower stations, but it can also be applied to rotor supports in other application environments. The method in this embodiment is mainly used to analyze the stress state of the rotor support under different operating conditions, enabling a more comprehensive and accurate analysis of the causes of rotor support cracks. Specifically, the analysis method in this embodiment includes: establishing a model of the rotor support under operating conditions; adding loads according to the characteristics of the new operating conditions; analyzing the stress deformation and fatigue strength of the rotor support under new and different operating conditions; obtaining the analysis and calculation results; and then comprehensively analyzing the causes of rotor support cracking based on the calculation results.

[0057] Based on the disclosure of the above embodiments, it can be understood that the beneficial effects of this embodiment include establishing a model of the generator rotor support under operating conditions, applying different loads that would be borne in real conditions to the model of the generator rotor support using the model, conducting simulation operation under different loads, obtaining various relevant stress data of the rotor support, and finally analyzing based on the stress data to determine the cause of the rotor support cracks. The method in this embodiment is simple in its overall process, easy to implement, and can all be completed by the equipment itself, greatly simplifying the user's operation, and the analysis results are highly accurate and have strong reference value.

[0058] Specifically, the establishment of the generator rotor support model under operating conditions in this embodiment includes:

[0059] Establish a generator rotor support model under the AGC (Automatic Generative Control) operating conditions of a hydropower station.

[0060] Optionally, the method in this embodiment further includes:

[0061] Constrain the generator rotor support model, including constraining the axial and tangential displacements of the mating surface between the rotor support and the main shaft.

[0062] For example, such as Figure 2 As shown, when establishing the rotor support model, the entire structure can be meshed using solid elements of type solid186. The magnetic pole mass is equivalent to a mass element applied to the outside of the yoke. Contact elements are used between the yoke and the clamping key, and between the clamping key and the main vertical rib. The clamping amount between the yoke and the rotor support is simulated through the interference contact between the yoke and the clamping key. After completing the model establishment, it is also necessary to determine the boundary conditions, including constraining the axial and tangential displacements of the mating surface between the rotor support and the main shaft.

[0063] Furthermore, the load on the generator rotor support model is automatically adjusted based on the operating conditions, and the stress changes of the generator rotor support model under load changes are determined, including:

[0064] Automatically adjust the load on the generator rotor support model based on operating conditions;

[0065] At least the stress change of the generator rotor support model during idling and after each load adjustment should be determined.

[0066] Optionally, the method in this embodiment further includes:

[0067] Determine the alternating stress amplitude of the generator in each cycle of operation.

[0068] At least based on the stress changes in the generator rotor support model, an analysis of the generator rotor support model should be conducted to determine the causes that would lead to cracks in the actual generator rotor support, including:

[0069] The generator rotor support model is analyzed based on the stress changes, the number of stress changes, and the alternating stress amplitude of the generator in each cycle of application, during idling and after each load adjustment. This analysis aims to determine the causes of cracks in the actual generator rotor support.

[0070] The analysis of the generator rotor support model, based on the stress changes during idling and after each load adjustment, and the alternating stress amplitude of the generator in each cycle of application, identifies the causes that would lead to cracks in the actual generator rotor support, including:

[0071] Based on the stress changes, stress frequency, and alternating stress amplitude of the generator rotor support model during idling and after each load adjustment, at least the cumulative damage and fatigue life of the generator rotor support model should be analyzed to determine the causes of cracks in the actual generator rotor support.

[0072] For example, such as Figure 3 and Figure 4 As shown, this embodiment adds load based on the force on the rotor support under AGC conditions, considering the periodic changes in force when the load is frequently adjusted. This includes the change in load on the rotor support during AGC operation, which is mainly reflected in the change of electromagnetic force. Before analysis, this embodiment needs to determine the stress state of the rotor support under idling conditions and the stress state of the rotor support during each load change. Since the load change amplitude is random, conservatively, this embodiment needs to determine an extreme case: the stress change of the rotor support under idling conditions (no electromagnetic force) and rated output conditions is considered to be the stress change of the rotor support during each AGC adjustment.

[0073] Furthermore, when estimating the fatigue life of actual rotor support components based on stress data, the number of cycles is easily determined in most cases. Each cycle consists of three stages: startup, normal operation, and shutdown. For each cycle, the maximum stress range must be determined, which is the algebraic difference between the maximum and minimum stress intensity in one cycle, thus obtaining the alternating stress amplitude, i.e., half of the maximum stress range. Based on the alternating stress amplitude, the allowable load cycle number corresponding to each stress range can be calculated from the fatigue curve. When the stress amplitude caused by load cycles differs, the linear accumulation method should be used for fatigue analysis. The linear fatigue cumulative damage theory states that under cyclic loading, fatigue damage can be linearly accumulated, with each stress independent and uncorrelated. When the accumulated damage reaches a certain value, the specimen or component will experience fatigue failure, i.e., cracks will appear in the rotor support. In this embodiment, the following calculations are performed based on the linear cumulative damage theory:

[0074] Damage caused by one cycle:

[0075] In the formula, N is the fatigue life corresponding to the current load level S.

[0076] Damage caused by n cycles under constant amplitude loading:

[0077] Damage caused by n cycles under variable amplitude loading:

[0078] In the above formulas, Ni represents the fatigue life corresponding to the current load level Si.

[0079] Critical fatigue damage D CR If it is a variable amplitude fatigue load, fatigue failure obviously occurs when the number of cyclic loads n equals its fatigue life N, that is, n = N. From the above formula, we can obtain D. CR =1.

[0080] When performing fatigue calculations under new operating conditions, if the load is adjusted, the load alternation time T can be determined according to the actual adjustment time of the power plant. Here, taking a power plant's statistical time T = 15s as an example, the number of times it participates in AGC adjustment over 40 years is N = 40 × 365 × 24 × 60 × 60 ÷ 15 = 8.41E7 times.

[0081] After the generator rotor support model has been operated under different loads, cracks may appear at parts 1 and 2, such as... Figure 5 , Figure 6 As shown, and based on as Figure 5 and Figure 6 The crack data and fatigue strength calculation results shown are as follows:

[0082] Table 1 shows the stress conditions at crack location 1 of the rotor support.

[0083]

[0084]

[0085] Table 2. Stress conditions at crack location 2 in the rotor support.

[0086]

[0087] According to the above calculation results, the cumulative fatigue damage coefficients of parts 1 and 2 of the generator rotor support model where cracks occur are both less than 1. Therefore, the calculation results show that cracks will not occur in these two parts. In other words, based on the data obtained in this embodiment and the above calculation and analysis results, it can be directly determined whether cracks will occur in this part based on the fatigue damage value. If cracks occur, it is due to improper stress and number of cycles at that location.

[0088] In addition, based on the above analysis of the stress and fatigue strength of the rotor support under different new operating conditions, the possibility that the rotor support cracks are caused by frequent load changes has been ruled out, which is conducive to further analysis of the causes of rotor support cracks.

[0089] like Figure 7 As shown, another embodiment of the present invention also provides a crack analysis device for a rotor support, comprising:

[0090] A module is created to build a generator rotor support model under operating conditions.

[0091] An adjustment module is used to automatically adjust the load on the generator rotor support model according to the operating conditions, and to determine the stress change of the generator rotor support model under the change of load.

[0092] The analysis module is used to analyze the generator rotor support model based at least on the stress changes of the generator rotor support model to determine the causes that would lead to cracks in the actual generator rotor support.

[0093] As an optional embodiment, the establishment of the generator rotor support model under operating conditions includes:

[0094] Establish a generator rotor support model under the AGC (Automatic Generative Control) operating conditions of a hydropower station.

[0095] As an optional embodiment, it also includes:

[0096] The generator rotor support model is constrained, including constraining the axial and tangential displacements of the mating surface between the rotor support and the main shaft.

[0097] As an optional embodiment, the step of automatically adjusting the load on the generator rotor support model based on operating conditions and determining the stress change of the generator rotor support model under load changes includes:

[0098] The load on the generator rotor support model is automatically adjusted based on the operating conditions.

[0099] At least the stress change of the generator rotor support model during idling and after each load adjustment should be determined.

[0100] As an optional embodiment, it also includes:

[0101] Determine the alternating stress amplitude of the generator in each cycle of application.

[0102] As an optional embodiment, the analysis of the generator rotor support model based at least on the stress changes of the generator rotor support model to determine the causes that would lead to cracks in the actual generator rotor support includes:

[0103] The generator rotor support model is analyzed based on the stress changes, number of changes, and alternating stress amplitude of the generator in each cycle of application, during idling and after each load adjustment, to determine the causes that would lead to cracks in the actual generator rotor support.

[0104] As an optional embodiment, the analysis of the generator rotor support model based on the stress change, number of changes, and alternating stress amplitude of the generator in each cycle of application during idling and after each load adjustment, to determine the causes that would lead to cracks in the actual generator rotor support, includes:

[0105] Based on the stress changes, number of changes, and alternating stress amplitude of the generator rotor support model during idling and after each load adjustment, at least the cumulative damage and fatigue life of the generator rotor support model should be analyzed to determine the causes that may lead to cracks in the actual generator rotor support.

[0106] Another embodiment of this application also provides an electronic device, including:

[0107] One or more processors;

[0108] Memory, configured to store one or more programs;

[0109] When the one or more programs are executed by the one or more processors, the one or more processors implement the crack analysis method for the rotor support described above.

[0110] One embodiment of this application also provides a storage medium storing a computer program that, when executed by a processor, implements the crack analysis method for the rotor support as described above. It should be understood that the various solutions in this embodiment have the corresponding technical effects in the above-described method embodiments, and will not be repeated here.

[0111] This application also provides a computer program product tangibly stored on a computer-readable medium and including computer-readable instructions. When executed, these computer-executable instructions cause at least one processor to perform a crack analysis method for a rotor support, such as the one described in the above embodiments. It should be understood that the various solutions in this embodiment have the corresponding technical effects in the above method embodiments, which will not be repeated here.

[0112] It should be noted that the computer storage medium of this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. Computer-readable media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections with one or more wires, portable computer disks, hard disks, random access storage media (RAM), read-only storage media (ROM), erasable programmable read-only storage media (EPROM or flash memory), optical fibers, portable compact disk read-only storage media (CD-ROM), optical storage media, magnetic storage media, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium other than computer-readable storage media, which can send, propagate, or transmit a program configured for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, antenna, optical fiber, RF, etc., or any suitable combination thereof.

[0113] It should be understood that although this application is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0114] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A crack analysis method for a rotor support, characterized in that, include: Establish a generator rotor support model under operating conditions; The load on the generator rotor support model is automatically adjusted based on the operating conditions, and the stress change of the generator rotor support model under the change of load is determined. The generator rotor support model is analyzed based on the stress changes of the generator rotor support model to determine the causes that would lead to cracks in the actual generator rotor support. This also includes: Determine the alternating stress amplitude and the number of cycles of the generator in each cycle of application; The automatic adjustment of load on the generator rotor support model based on operating conditions, and the determination of stress changes in the generator rotor support model under load changes, include: The load on the generator rotor support model is automatically adjusted based on the operating conditions. At least determine the stress change of the generator rotor support model during idling and after each load adjustment; The analysis of the generator rotor support model based at least on stress changes in the generator rotor support model to determine the causes that would lead to cracks in the actual generator rotor support includes: Based on the stress changes, number of changes, and alternating stress amplitude of the generator rotor support model during idling and after each load adjustment, at least the cumulative damage and fatigue life of the generator rotor support model should be analyzed to determine the causes that may lead to cracks in the actual generator rotor support.

2. The method according to claim 1, characterized in that, The establishment of the generator rotor support model under operating conditions includes: Establish a generator rotor support model under the AGC (Automatic Generative Control) operating conditions of a hydropower station.

3. The method according to claim 2, characterized in that, Also includes: The generator rotor support model is constrained, including constraining the axial and tangential displacements of the mating surface between the rotor support and the main shaft.

4. A crack analysis device for a rotor support, characterized in that, include: A module is created to build a generator rotor support model under operating conditions. An adjustment module is used to automatically adjust the load on the generator rotor support model according to the operating conditions, and to determine the stress change of the generator rotor support model under the change of load. The analysis module is used to analyze the generator rotor support model based at least on the stress changes of the generator rotor support model, and to determine the causes that would cause cracks in the actual generator rotor support. This also includes: The determination module is used to determine the alternating stress amplitude and the number of cycles of the generator in each cycle of application. The step of automatically adjusting the load on the generator rotor support model according to the operating conditions and determining the stress change of the generator rotor support model under the change of load includes: The load on the generator rotor support model is automatically adjusted based on the operating conditions. At least determine the stress change of the generator rotor support model during idling and after each load adjustment; The analysis of the generator rotor support model based at least on stress changes in the model to determine the causes that would lead to cracks in the actual generator rotor support includes: Based on the stress changes, number of changes, and alternating stress amplitude of the generator rotor support model during idling and after each load adjustment, at least the cumulative damage and fatigue life of the generator rotor support model should be analyzed to determine the causes that may lead to cracks in the actual generator rotor support.

5. The crack analysis device for the rotor support according to claim 4, characterized in that, Also includes: The generator rotor support model is constrained, including constraining the axial and tangential displacements of the mating surface between the rotor support and the main shaft.

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