Method and system for detecting cracks of flow passage component of hydroelectric generating set

Abstract

The invention discloses a hydroelectric generating set flow passage component crack detection method and detection system. The hydroelectric generating set flow passage component crack detection method comprises the following steps: S1, constructing a flow passage component and array eddy current probe simulation model; s2, simulating a plurality of crack states at a plurality of positions on the flow passage component simulation model; s3, simulating detection of the array eddy current probe on multiple crack states at multiple positions; s4, generating a crack state database of the flow passage component; s5, manufacturing the array eddy current probe according to the array eddy current probe simulation parameters; s6, the array eddy current probe detects the flow passage component to obtain entity detection data, and the encoder records the detection track of the array eddy current probe; s7, obtaining a corresponding crack state in the crack state database according to the entity detection data; and S8, generating a crack distribution image of the flow passage component according to the detection track and the corresponding crack state. According to the crack detection method for the flow passage component of the hydroelectric generating set, nondestructive detection on the surface of the flow passage component can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of hydro-generator unit detection, and in particular to a method and a system for detecting cracks in the flow-through components of a hydro-generator unit. Background Art

[0002] As an important part of a hydro-generator unit, the flow-through metal components play roles such as diverting water and regulating flow for the hydro-generator unit, including the runner of the water turbine, the guide mechanism, the water intake pipe, the draft tube, etc. Their quality status is related to the safe and economic operation of the hydro-generator unit. During the in-service operation of the flow-through metal components, they are continuously scoured and corroded by water flow for a long time, and a large amount of sediment and corrosive substances are mixed in the water flow. In addition, with the increase of the water head pressure and the water flow velocity, the wear and corrosion of the flow-through metal components are aggravated, seriously affecting the service life of the flow-through metal components of the unit. For this reason, a special anti-corrosion coating is applied on the surface of the flow-through metal components to prevent the scouring and corrosion of the water flow, thereby protecting the quality status of the flow-through metal components.

[0003] During the long-term operation of the flow-through metal components, they are subjected to the actions of water flow impact, unit vibration, fatigue load, etc., resulting in surface cracks in some parts and then crack propagation and fracture, seriously affecting the safe operation of the unit. According to the standard provisions of DL / T1314-2014 "Technical Supervision Regulations for Metals in Hydropower Plants", during each A / B-class maintenance of the hydro-generator unit, surface non-destructive testing needs to be carried out on the flow-through metal components in order to timely detect surface cracks on the metal and eliminate potential safety hazards of the equipment. The standard provisions of NB / T47013.4-2015 "Non-destructive Testing of Pressure Equipment - Part 4: Magnetic Particle Testing" and NB / T47013.5-2015 "Non-destructive Testing of Pressure Equipment - Part 5: Penetrant Testing" stipulate that when magnetic particle or penetrant testing is carried out on metal components, there should be no grease, dirt, rust, fiber debris and other substances that affect the test results on the workpiece surface, the surface roughness Ra≤25μm, and when magnetic particle testing is required, the thickness of the non-magnetic coating on the workpiece surface should not exceed 0.05mm. The standard requirements of SL105-2007 "Code for Anti-corrosion of Hydraulic Metal Structures" require that the surface coating of hydraulic metal components ≥160μm, and for the flow-through metal components to prevent the shedding and scouring of the coating during operation, the coating thickness is further increased. This coating thickness does not meet the surface condition requirements for non-destructive testing of the flow-through metal components, so it is necessary to grind and remove the surface coating of the flow-through metal components before carrying out surface non-destructive testing work.

[0004] When grinding and removing the coating, an angle grinder will cause damage to the metal surface, thinning the wall thickness of the metal material. After the surface non-destructive testing is completed, the coating needs to be restored, and a certain drying time is required, wasting a large amount of manpower, material resources and construction period. In addition, some power stations adopt the one-pipeline-multiple-units mode, that is, one water diversion pipeline leads out multiple branch pipes to connect multiple units. Only after the surface non-destructive testing of the entire water diversion pipeline is completed and the coating is restored can it be put into operation, making the construction period even more tense. When using conventional magnetic particle and penetrant testing, the pre-preparation processes such as coating grinding and the time for coating restoration after testing cannot guarantee the maintenance construction period. When using conventional eddy current testing, the sensitivity is low, and it is sensitive to the directionality of defects such as cracks, which does not meet the high standards of metal detection for current hydropower units. Currently, each hydropower station urgently needs a method for surface non-destructive testing of the metal components in the flow-through parts of hydropower units without removing the coating. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, the present invention provides a method for detecting cracks in the flow-through components of a hydropower unit, and the method for detecting cracks in the flow-through components of a hydropower unit can achieve surface non-destructive testing of the flow-through components.

[0006] The present invention also provides a detection system applying the above method for detecting cracks in the flow-through components of a hydropower unit.

[0007] The method for detecting cracks in the flow-through components of a hydropower unit according to the first aspect of the present invention includes: S1, constructing a simulation model of the flow-through component and a simulation model of an array eddy current probe; S2, simulating various crack states at multiple positions on the simulation model of the flow-through component; S3, simulating the detection of the array eddy current probe for various crack states at multiple positions and collecting corresponding simulated detection data; S4, generating a crack state database of the flow-through component according to the simulated detection data and the corresponding crack states; S5, manufacturing an array eddy current probe according to the simulation parameters of the array eddy current probe; S6, using the array eddy current probe to detect the flow-through component to obtain actual detection data, and an encoder records the detection trajectory of the array eddy current probe; S7, obtaining the corresponding crack state in the crack state database according to the actual detection data; S8, generating an image of the crack distribution of the flow-through component according to the detection trajectory and the corresponding crack state.

[0008] The method for detecting cracks in the flow-through components of a hydropower unit according to the first aspect of the present invention can achieve surface non-destructive testing of the flow-through components, and can improve the detection efficiency and detection accuracy.

[0009] According to some embodiments of the present invention, step S3 includes: S31. Determine the imaging effects of the simulated detection data at multiple positions respectively. If the imaging effects of the simulated detection data at multiple positions all meet the set requirements, collect the simulated detection data and proceed to step S4. If the imaging effect of the simulated detection data at a certain position does not meet the set requirements, adjust the simulation detection parameters of the array eddy current probe at this position, re-perform the simulation detection at this position and collect the simulated detection data, and repeat step S31.

[0010] According to some embodiments of the present invention, between step S5 and step S6, it further includes: S51. Select several flow-through component models as verification models, select several positions on the verification models as verification positions, select a simulated crack state at the verification positions as the verification state, and fabricate a verification piece according to the parameters of the verification models, the verification positions and the verification state; S52. Use the array eddy current probe to detect the verification piece to obtain verification detection data; S53. Compare the verification detection data with the simulated detection data corresponding to the verification state. If the deviation between the verification detection data and the corresponding simulated detection data is less than or equal to A, proceed to step S6. If the deviation between the verification detection data and the corresponding simulated detection data is greater than A, adjust the simulation parameters of the array eddy current probe and proceed to step S2.

[0011] According to some embodiments of the present invention, before step S6, it further includes: S60. Calibrate the encoder.

[0012] According to some embodiments of the present invention, constructing the flow-through component simulation model includes: S11. Measure the size and material properties of the flow-through component to obtain the size parameters and material property parameters of the flow-through component; S12. According to the size parameters and material property parameters of the flow-through component, construct the simulation model of the flow-through component in the simulation software.

[0013] According to some embodiments of the present invention, the flow-through component includes: a component body and a coating. The coating is coated on the surface of the component body. The size parameters include: the three-dimensional size of the component body and the thickness of the coating; the material property parameters include: the material of the component body, the magnetic permeability of the component body, the conductivity of the component body, the magnetic permeability of the coating and the conductivity of the coating.

[0014] According to some embodiments of the present invention, the flow-through component includes: a water turbine runner, a guide vane mechanism, a water inlet pipe and a draft tube.

[0015] The detection system according to the second aspect of the present invention applies the crack detection method for the flow-through components of a hydroelectric unit according to the first aspect of the present invention. The detection system includes: a computer, which is used to construct and store a crack status database of the flow-through components and process the detection data; an array eddy current probe and an encoder, both the array eddy current probe and the encoder are electrically connected to the computer; a display unit, the display unit is electrically connected to the computer, and the display unit is used to display the crack distribution image of the flow-through components.

[0016] By applying the crack detection method for the flow-through components of a hydroelectric unit according to the first aspect of the present invention, the detection system according to the second aspect of the present invention can achieve non-destructive detection of the surface of the flow-through components, and can improve the detection efficiency and detection accuracy.

[0017] According to some embodiments of the present invention, the detection system further includes: a detection bracket, and both the array eddy current probe and the encoder are arranged on the detection bracket.

[0018] According to some embodiments of the present invention, the flow-through component includes a plurality of flow-through parts, the array eddy current probes are multiple, and the multiple array eddy current probes correspond to the multiple flow-through parts one by one.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0020] Figure 1 is a flowchart of the crack detection method for the flow-through components of a hydroelectric unit according to an embodiment of the present invention;

[0021] Figure 2 is Figure 1 a flowchart of step S3 shown in

[0022] Figure 3 is a flowchart of the crack detection method for the flow-through components of a hydroelectric unit according to another embodiment of the invention. Detailed Embodiments

[0023] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0024] The following refers to Figures 1-3 to describe the crack detection method for the flow-through components of a hydroelectric unit according to an embodiment of the first aspect of the present invention.

[0025] AsFigure 1 As shown in Figure 1 , the crack detection method for the flow-through components of a hydropower unit according to the first aspect embodiment of the present invention includes:

[0026] S1. Build a simulation model of the flow-through component and an array eddy current probe simulation model.

[0027] Model the flow-through component according to its actual parameters in simulation software such as SolidWorks, and model the array eddy current probe by setting its structural parameters and detection parameters in simulation software such as CIVA simulation software.

[0028] Among them, the structural parameters of the array eddy current probe include: probe shape, coil size, number of excitation coils and induction coils, number of turns, arrangement method, and spacing, etc. For example, the probe shape can be rectangular, circular, polygonal, or irregular.

[0029] The detection parameters include: excitation frequency, excitation current, lift-off distance, phase, and filtering parameters, etc.

[0030] S2. Simulate various crack states at multiple positions on the simulation model of the flow-through component.

[0031] Import the simulation model of the flow-through component built by SolidWorks into CIVA simulation software, simulate the crack states in CIVA simulation software, and simulate multiple crack states at one position. Among them, the crack states include: crack length, depth, and extension direction.

[0032] S3. Simulate the detection of various crack states at multiple positions by the array eddy current probe and collect the corresponding simulated detection data.

[0033] Use the built array eddy current probe model in CIVA simulation software to simulate the detection of the flow-through component.

[0034] S4. Generate a crack state database for the flow-through component according to the simulated detection data and the corresponding crack states.

[0035] It can be understood that one crack state corresponds to the simulated detection data of an array eddy current probe, and the corresponding relationship between the simulated detection data and the crack states constitutes the crack state database.

[0036] S5. Manufacture the array eddy current probe according to the simulation parameters of the array eddy current probe.

[0037] Among them, at different positions of the flow-through component, due to the different sizes, materials, and coating thicknesses of the flow-through component, the detection parameters adapted to the flow-through component are also different. In the array eddy current probe simulation model, manufacture the corresponding array eddy current probe according to the detection parameters adapted to different positions of the flow-through component.

[0038] The parameters of the array eddy current probe include: excitation frequency, acquisition frequency, the shape of the probe, the size of the coil, the number of excitation coils and induction coils, the number of turns of the excitation coils and induction coils, the arrangement of the excitation coils and induction coils, and the spacing between the excitation coils and induction coils.

[0039] S6. The array eddy current probe detects the current-carrying component to obtain the entity detection data, and the encoder records the detection trajectory of the array eddy current probe.

[0040] The array eddy current probe is attached to the surface of the current-carrying component to detect the current-carrying component. During the detection process, the array eddy current probe will not damage the structure of the current-carrying component.

[0041] S7. Obtain the corresponding crack state in the crack state database according to the entity detection data.

[0042] Take the entity detection data as the simulated detection data. The computer matches the corresponding crack state in the crack state database, and this crack state is used as the actual detection result of the current-carrying component.

[0043] S8. Generate an image of the crack distribution of the current-carrying component according to the detection trajectory and the corresponding crack state.

[0044] The computer processes the detection trajectory and the corresponding crack state, and displays the image of the crack distribution of the current-carrying component on the display unit. Among them, during use, A-type display or C-type display can be selected according to the use requirements.

[0045] Thus, non-destructive detection of cracks in the current-carrying component can be realized, and the operation process is simple and convenient, which can improve the detection efficiency. At the same time, the detection accuracy of the array eddy current probe is relatively high, which can improve the accuracy of crack detection of the current-carrying component.

[0046] According to the method for detecting cracks in the current-carrying component of the water turbine unit according to the first aspect embodiment of the present invention, non-destructive detection of the surface of the current-carrying component can be realized, and the detection efficiency and detection accuracy can be improved.

[0047] In some embodiments of the present invention, as Figure 2 shown, step S3 includes:

[0048] S31. Determine the imaging effects of the simulated detection data at multiple positions respectively.

[0049] If the imaging effects of the simulated detection data at multiple positions all meet the set requirements, collect the simulated detection data and enter step S4.

[0050] If the imaging effect of the simulated detection data at a certain position fails to meet the set requirements, adjust the simulation detection parameters of the array eddy current probe at this position, re - conduct the simulated detection on this position and collect the simulated detection data, and repeat step S31.

[0051] It can be understood that at different positions of the over - current component, the coating thickness and material dimensions may be different, and the detection parameters that enable the array eddy current probe to clearly image are also different. When the array eddy current probe is detecting, when the signal difference intensity is relatively high, the imaging effect is also better. During the execution process, compare whether the signal difference intensity of the detection signals at different positions of the filter component is greater than the set signal difference intensity to determine whether the imaging effect at this filter part can meet the requirements. Among them, the set signal difference intensity can be adjusted according to the required detection accuracy.

[0052] When the simulation detection parameters of the array eddy current probe at multiple positions can all make the imaging effect meet the set requirements, collect the simulated detection data and enter step S4.

[0053] In some embodiments of the present invention, as Figure 3 shown, between step S5 and step S6, it further includes:

[0054] S51: Select several over - current component models as verification models, select several positions on the verification models as verification positions, select a simulated crack state at the verification positions as the verification state, and make a verification piece according to the parameters of the verification model, the verification positions and the verification state.

[0055] The body material of the verification piece is the same as the component body material of the over - current component. Open a crack at the position corresponding to the verification position on the verification piece that is the same as the verification state, and then apply a coating on the verification piece that is consistent with the verification model.

[0056] S52: Use the array eddy current probe to detect the verification piece and obtain verification detection data.

[0057] S53: Compare the verification detection data with the simulated detection data corresponding to the verification state.

[0058] If the deviation between the verification detection data and the corresponding simulated detection data is less than or equal to A, enter step S6.

[0059] At this time, it is determined that the accuracy of the simulated detection data meets the test requirements.

[0060] If the deviation between the verification detection data and the corresponding simulated detection data is greater than A, adjust the simulation parameters of the array eddy current probe and enter step S2.

[0061] At this time, it is determined that the accuracy of the simulated detection data cannot meet the test requirements, and it is necessary to adjust the simulation parameters of the array eddy current probe until the accuracy of the simulated detection data meets the test requirements.

[0062] During the execution process, the value of A can be set according to the detection accuracy requirements. For example, the value of A can be within 5%.

[0063] In some embodiments of the present invention, before step S6, it further includes: S60, calibrating the encoder.

[0064] Calibrate the encoder according to the actual structure of the overcurrent component, thereby improving the detection accuracy.

[0065] In some embodiments of the present invention, constructing the overcurrent component simulation model includes:

[0066] S11, measuring the dimensions and material properties of the overcurrent component to obtain the dimension parameters and material property parameters of the overcurrent component;

[0067] S12, constructing the simulation model of the overcurrent component in the simulation software according to the dimension parameters and material property parameters of the overcurrent component.

[0068] In this way, modeling according to the actual parameters of the overcurrent component can further improve the accuracy of the simulated detection data, thereby further improving the detection accuracy.

[0069] In some embodiments of the present invention, the overcurrent component includes: a component body and a coating. The coating is applied on the surface of the component body. The dimension parameters include: the three-dimensional dimensions of the component body and the thickness of the coating. The material property parameters include: the material of the component body, the magnetic permeability of the component body, the conductivity of the component body, the magnetic permeability of the coating, and the conductivity of the coating.

[0070] During the detection process, use a portable magnetic permeability meter and a portable conductivity meter to measure the magnetic permeability and conductivity of different regions of the component body and its surface coating respectively for multiple times, and calculate the average value as the corresponding parameter during modeling. Use a coating thickness gauge to measure the coating thickness of different regions on the surface of the component body, and use a portable alloy analyzer to measure the material composition of the component body.

[0071] In some embodiments of the present invention, the overcurrent components include: a water turbine runner, a guide vane mechanism, a water inlet pipe, and a draft tube. By using the crack detection method for the overcurrent components of the hydropower unit in this embodiment to detect the water turbine runner, the guide vane mechanism, the water inlet pipe, and the draft tube, non-destructive detection can be realized, thereby reducing the impact of the detection on the normal operation of the hydropower unit.

[0072] The detection system according to the second aspect of the present invention applies the above-mentioned crack detection method for the flow-through components of the hydropower unit according to the first aspect of the present invention. The detection system includes: a computer, an array eddy current probe, an encoder, and a display unit.

[0073] Specifically, the computer is used to construct and store the crack status database of the flow-through components and process the detection data. Both the array eddy current probe and the encoder are electrically connected to the computer, and the display unit is electrically connected to the computer. The display unit is used to display the crack distribution image of the flow-through components.

[0074] During the working process, first, the crack status database of the flow-through components is constructed in the computer, and then the array eddy current probe detects the flow-through components. Among them, the skeleton of the array eddy current probe is made of flexible material to reduce damage to the flow-through components. The encoder records the movement trajectory of the array eddy current probe. The detection data of the array eddy current probe and the movement trajectory recorded by the encoder are transmitted to the computer. The computer matches the corresponding crack information in the crack status database and outputs the correspondence between the movement trajectory and the crack information, so that the display unit displays the crack distribution image of the flow-through components.

[0075] According to the detection system of the embodiment of the second aspect of the present invention, by applying the above-mentioned crack detection method for the flow-through components of the hydropower unit according to the first aspect of the present invention, non-destructive detection of the surface of the flow-through components can be realized, and the detection efficiency and detection accuracy can be improved.

[0076] In some embodiments of the present invention, the detection system further includes: a detection bracket. Both the array eddy current probe and the encoder are arranged on the detection bracket. By setting the detection bracket, the detection difficulty can be reduced, and the detection accuracy can be further improved. Moreover, both the array eddy current probe and the encoder are arranged on the detection bracket, which can reduce the interference of the connection structure between the array eddy current probe and the encoder during the detection process and further reduce the detection difficulty.

[0077] In some embodiments of the present invention, the flow-through components include multiple flow-through parts, and there are multiple array eddy current probes. The multiple array eddy current probes correspond to the multiple flow-through parts one by one.

[0078] Among them, the parameters of the array eddy current probes corresponding to different flow-through parts are also different. During the detection process, by using different array eddy current probes to detect the corresponding flow-through parts, the detection accuracy can be further improved.

[0079] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0080] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0081] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral body; it may be a mechanical connection, an electrical connection, or a communication connection; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0083] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for detecting cracks in flow-through components of a hydropower unit, characterized in that: include: S1. Construct a simulation model of the flow-through components and a simulation model of the array eddy current probe; S2. Simulating various crack states at multiple locations on the simulation model of the flow-through component; S3, simulating the detection of various crack states at multiple locations by an array eddy current probe, and collecting corresponding simulated detection data; S4. Generate a crack state database of the flow-through component according to the simulated detection data and the corresponding crack state; S5, manufacturing an array eddy current probe according to the simulation parameters of the array eddy current probe; S6, the array eddy current probe detects the flow-through components to obtain entity detection data, and the encoder records the detection track of the array eddy current probe; S7. Obtaining a corresponding crack state in a crack state database according to the entity detection data; S8. Generate a crack distribution image of the flow-through component according to the detection trajectory and the corresponding crack state.

2. The method for detecting cracks in flow-through components of a hydropower unit according to claim 1, characterized in that: The step S3 comprises: S31, respectively determining the imaging effects of the simulated detection data at multiple positions, If the imaging effects of the simulated detection data at multiple positions all meet the set requirements, the simulated detection data are collected and the process proceeds to step S4. If the imaging effect of the simulated detection data of a certain position does not meet the set requirements, the simulation detection parameters of the array eddy current probe at the position are adjusted, the position is simulated detected again and the simulated detection data is collected, and step S31 is repeated.

3. The method for detecting cracks in flow-through components of a hydropower unit according to claim 1, characterized in that: Also included between step S5 and step S6: S51, selecting several flow-through component models as verification models, selecting several positions on the verification models as verification positions, selecting a simulated crack state of the verification positions as the verification state, and manufacturing verification pieces according to the parameters of the verification models, the verification positions and the verification states; S52, using an array eddy current probe to test the verification component and obtain verification test data; S53, comparing the verification test data with the simulation test data corresponding to the verification state, If the deviation between the verification test data and the corresponding simulation test data is less than or equal to A, then proceed to step S6. If the deviation between the verification test data and the corresponding simulation test data is greater than A, the simulation parameters of the array eddy current probe are adjusted and the process goes to step S2.

4. The method for detecting cracks in flow-through components of a hydropower unit according to claim 1, characterized in that: Before step S6, the method further includes: S60, calibrate the encoder.

5. The method for detecting cracks in flow-through components of a hydropower unit according to claim 1, characterized in that: The construction of the simulation model of the flow-through component comprises: S11, measuring the size and material properties of the flow-through components to obtain the size parameters and material property parameters of the flow-through components; S12. Construct a simulation model of the flow-through component in the simulation software according to the size parameters and material characteristic parameters of the flow-through component.

6. The method for detecting cracks in flow-through components of a hydropower unit according to claim 5, characterized in that: The flow-through component comprises: a component body and a coating, wherein the coating is coated on the surface of the component body, and the size parameters comprise: a three-dimensional size of the component body and a thickness of the coating; The material characteristic parameters include: the material of the component body, the magnetic permeability of the component body, the electrical conductivity of the component body, the magnetic permeability of the coating and the electrical conductivity of the coating.

7. The method for detecting cracks in flow-through components of a hydropower unit according to claim 1, characterized in that: The flow-through components include: a turbine runner, a water guide mechanism, a water diversion pipeline and a tailwater pipe.

8. A detection system, characterized in that: The method for detecting cracks in flow-through components of a hydropower unit according to any one of claims 1 to 7 is applied, wherein the detection system comprises: A computer, the computer is used to construct and store a crack state database of the current-passing components and process the detection data; An array eddy current probe and an encoder, wherein the array eddy current probe and the encoder are both electrically connected to the computer; A display unit is electrically connected to the computer, and is used to display a crack distribution image of the flow-through component.

9. The detection system according to claim 8, characterized in that: Also includes: A detection bracket, on which the array eddy current probe and the encoder are both arranged.

10. The detection system according to claim 8, characterized in that: The flow component includes a plurality of flow locations, and there are a plurality of array eddy current probes, and the plurality of array eddy current probes correspond one-to-one to the plurality of flow locations.

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