Sensor device for detecting cable defects

Abstract

The utility model provides a sensor device for detecting cable defects, which comprises a shell and a detection structure, and is characterized in that the detection structure is arranged in the shell and is used for fixing the detection structure on a power transmission line; and the detection structure comprises an exciting coil and a receiving coil and is used for performing magnetic flux leakage detection and eddy current detection on the power transmission line. Nondestructive detection of the power transmission line is realized by adopting a pulsed eddy current detection technology. A detection structure is established by relying on a Maxwell equation, an annular eddy current is excited in a power transmission line by utilizing pulse excitation, then a differential signal difference is generated at a defect position, and defect positioning and defect quantification are realized by analyzing and outputting a differential signal.

Description

Technical Field

[0001] The utility model relates to the technical field of cable detection, in particular to a sensor device for detecting cable defects. Background Art

[0002] With the rapid development of the power industry, the scale of the power grid is constantly expanding, and the requirements for the safety and reliability of transmission lines are also getting higher and higher. Therefore, it is very necessary to adopt effective detection methods to conveniently and accurately detect various damages such as cracks, broken strands, offset and separation of compression joints in transmission lines and the damage locations, so as to provide a reference basis for line maintenance. However, traditional transmission line defect detection methods often have problems such as complex operation, time-consuming and laborious, and low detection accuracy, and it is difficult to meet the current power grid operation requirements. Therefore, developing a new type of and efficient non-destructive detection technology for transmission lines has become an urgent problem to be solved in the current power industry.

[0003] Transmission lines work outdoors for a long time and are subjected to various complex climates and harsh natural environments. The brittle change of materials caused by day-night temperature difference and climate change, lightning strikes and electrical flashovers will cause surface damage to the transmission lines. In areas with high air humidity and high salt content such as coastal cities and industrial parks, it will even cause serious chemical corrosion to the transmission lines; the transmission lines themselves also bear the pressure of electrical load and mechanical load. Under the combined action of the above factors, it is inevitable that cracks, broken strands and other defects will appear in the aluminum stranded wire on the surface and the steel core inside the transmission lines. If the hidden dangers existing in the transmission lines cannot be discovered in time and allowed to deteriorate further, resulting in the disconnection of the transmission lines, it will cause the entire power grid system to collapse, thus causing huge economic losses.

[0004] At present, the process of non-destructive detection of transmission lines is relatively slow. For example, in the existing magnetic flux leakage detection method proposed in the journal "Research and Development Status of Magnetic Flux Leakage Detection Technology" with the ISSN 1673 - 257X, ferromagnetic materials are magnetized by an external magnetic field, so that an ordered magnetization structure is generated inside the materials. When there are defects or damages in the materials, the magnetization structures in these areas will change, resulting in the distortion of magnetic flux lines at the defects and partial escape to the outside of the materials, forming a magnetic flux leakage field. It is these magnetic flux leakage fields that provide important information about the location and nature of the defects for us.

[0005] When attempting to use the magnetic flux leakage detection method to detect non-ferromagnetic materials, the main defects include:

[0006] Material limitation: The magnetic flux leakage detection method is based on the magnetization characteristics of ferromagnetic materials. The magnetic permeability of non-ferromagnetic materials (such as aluminum, copper, etc.) is close to 1, which makes them hardly show magnetization phenomena in an external magnetic field. Therefore, the magnetic flux leakage detection method cannot induce an obvious magnetic flux leakage field in non-ferromagnetic materials, and thus cannot detect the internal defects.

[0007] Detection sensitivity: The sensitivity of the magnetic flux leakage detection method is affected by the magnetic properties of the material. For non-ferromagnetic materials, due to their extremely low magnetic permeability, even if there are defects, it is difficult to generate a detectable magnetic flux leakage field on the material surface. This results in a significant reduction in the sensitivity of the magnetic flux leakage detection method in the detection of non-ferromagnetic materials.

[0008] Difficulty in signal processing: In non-ferromagnetic materials, since the magnetic flux leakage field is very weak or even may not exist, it makes the acquisition and processing of detection signals very difficult. Traditional magnetic flux leakage detection signal processing methods may not be able to effectively extract and analyze these weak signals, resulting in a reduction in the accuracy and reliability of the detection results.

[0009] Technical challenges: Although using stronger magnetic fields, developing more sensitive magnetic sensors, etc. to improve the detection ability of the magnetic flux leakage detection method in non-ferromagnetic materials, these technological improvements often face problems such as high implementation difficulty and high cost. In addition, even if these technological improvements are achieved, they may not be able to completely overcome the limitations of the magnetic flux leakage detection method in the detection of non-ferromagnetic materials. Summary of the Invention

[0010] According to the above-mentioned technical problems, a sensor device for detecting cable defects is provided. The utility model mainly uses three sensors, each responsible for detecting a 120° spatial range, so as to realize the method of circumferential detection of the cable.

[0011] The technical means adopted by the utility model are as follows:

[0012] A sensor device for detecting cable defects, comprising: a housing and a detection structure, wherein:

[0013] The housing is internally provided with a detection structure for fixing the detection structure on the transmission line;

[0014] The detection structure includes an excitation coil and a receiving coil for performing magnetic flux leakage detection and eddy current detection on the transmission line.

[0015] Further, the housing includes: a shell and a bracket, wherein:

[0016] The shell is composed of three identical sector cylinders, and the shell is provided with mounting holes. The mounting holes are coaxial with the shell, and the central axis of the shell coincides completely with the central axis of the mounting holes;

[0017] The shell is a hollow cylindrical structure, and brackets are provided in the middle of the outer sides of the sector cylinders.

[0018] Further, the detection structure includes 3 excitation coils and 3 receiving coils, wherein:

[0019] The included angle between the three exciting coils is 120°, which equally divides the transmission line into three parts for generating pulsed magnetic fields. A receiving coil is arranged at the middle position between two adjacent exciting coils, and the receiving coil is used to capture and analyze the magnetic field signals generated by eddy currents.

[0020] Further, the detection structure further includes a shielding cover;

[0021] The shielding cover is arranged above the exciting coil to suppress the direct coupling between the exciting coil and the receiving coil and shield interference signals.

[0022] Further, the outer shell is made of carbon fiber composite material.

[0023] Compared with the prior art, the present utility model has the following advantages:

[0024] The sensor device for detecting cable defects provided by the present utility model uses pulsed eddy current testing (PEC) technology to achieve non-destructive testing of transmission lines because the pulsed signal has good observability and flexible adjustability. The detection structure is established based on Maxwell's equations, and pulsed excitation is used to excite circular eddy currents inside the transmission line, thereby generating differential signal differences at the defect positions. By analyzing the output differential signals, defect location and defect quantification are realized.

[0025] For the sensor device for detecting cable defects provided by the present utility model, in order to accurately identify the radial position of the defect, three exciting coils and three receiving coils are used to cover the entire circumference of the pipeline. The improved probe structure can increase the observation dimension, estimate more parameters, and improve the probe performance. Using multiple excitation sources can concentrate more energy in the RF region, which helps to improve the signal strength. The distribution of the magnetic flux density lines around the pipeline is numerically simulated using COMSOL multiphysics software, which proves this idea.

[0026] Based on the above reasons, the present utility model can be widely promoted in the field of cable detection technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a schematic diagram of the outer shell structure in the present utility model.

[0029] Figure 2 It is a schematic diagram of the detection structure in the present utility model.

[0030] Figure 3 This is a sectional view of the detection structure in the present utility model installed on a transmission line.

[0031] Figure 4 These are the experimental parameters in the embodiments of the present utility model.

[0032] In the figure: 1. Housing; 2. Sector column; 3. Mounting hole; 4. Bracket; 5. Excitation coil; 6. Receiver coil; 7. Shielding cover. Specific implementation manners

[0033] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0035] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: similar reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0037] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description. Without contrary statements, these orientation terms do not indicate and imply that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as limiting the protection scope of the present invention: the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0038] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" can be used here to describe the spatial positional relationships of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientations described in the drawings for the devices. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned as "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations are made for the spatial relative descriptions used here.

[0039] In addition, it should be noted that the use of words such as "first", "second" to limit components is only for the convenience of differentiating the corresponding components. Without otherwise stating, the above words have no special meanings, and thus cannot be construed as limiting the protection scope of the present invention.

[0040] Such as Figure 1As shown in the figure, the present utility model provides a sensor device for detecting cable defects, including: a housing and a detection structure, where:

[0041] The housing has a detection structure inside, which is used to fix the detection structure on the transmission line;

[0042] The detection structure includes an excitation coil 5 and a receiving coil 6, which are used for magnetic flux leakage detection and eddy current detection of the transmission line.

[0043] In specific implementation, as a preferred implementation manner, the housing includes: a housing body 1 and a bracket 4, where:

[0044] The housing body 1 is composed of three identical sector cylinders 2. An installation hole 3 is provided on the housing body 1. The installation hole 3 is coaxial with the housing body 1, and the central axis of the housing body 1 coincides completely with the central axis of the installation hole 3;

[0045] The housing body 1 is a hollow cylindrical structure. Brackets are provided in the middle of the outer sides of the sector cylinders 2. The sensor device for detecting cable defects is installed on the transmission line through the installation hole.

[0046] In specific implementation, as a preferred implementation manner, the detection structure includes 3 excitation coils 5 and 3 receiving coils 6, where:

[0047] The included angle between the 3 excitation coils 5 is 120°, dividing the transmission line into three equal parts, which is used to generate a pulsed magnetic field; a receiving coil 6 is arranged at the middle position between two adjacent excitation coils 5, and the receiving coil 6 is used to capture and analyze the magnetic field signals generated by eddy currents.

[0048] The probe design adopts an innovative layout, in which the double exciters are arranged along the circumferential direction of the pipeline. This layout not only enhances the indirect field, but also effectively reduces the size of the probe, making it more flexible and convenient to operate. In practical applications, through multiple experiments and optimizations, it is found that when the angle between the excitation coils is set to 120°, a relatively stronger signal amplitude can be generated. This angle setting, based on the electromagnetic field theory, can maximize the interaction between the coils, thereby improving the signal quality and detection sensitivity. In addition, the receiver coil is cleverly placed at the middle position between the double excitation coils. Such a layout helps the receiver coil capture signals from all directions, improving the signal reception efficiency and detection accuracy.

[0049] To further improve the performance of the probe, the design also includes the use of a shielding cage. The function of the shielding cage is to suppress the direct coupling energy between the exciter and the receiver coils, reducing the interference of useless signals. This design significantly improves the ability to measure deep hidden defects and also enhances the ability to identify the radial position of defects, providing strong technical support for the precise positioning of defects. Based on this probe structure, the further improved design uses three excitation coils and three receiving coils, comprehensively covering the entire circumference of the pipeline. Compared with the previous probe structures, this design can detect the response signals of the pipeline circumference from different angles through the use of multiple receiving coils, thus increasing the dimension of observation. This multi-dimensional detection ability enables the probe to estimate more parameters, such as the thickness of the pipeline wall, material properties, stress distribution, etc., providing richer data for the integrity assessment of the pipeline.

[0050] At the same time, the use of multiple excitation coils makes the probe structure more compact, which not only improves the portability of the probe but also enables it to adapt to smaller pipelines or more complex detection environments. The compact design also helps to reduce the interference of the external environment on the detection results, further improving the stability and reliability of the detection.

[0051] During specific implementation, as a preferred implementation method, the detection structure further includes a shielding cover 7;

[0052] The shielding cover 7 is arranged above the excitation coil and is used to suppress the direct coupling between the excitation coil 5 and the receiving coil 6 and shield the interference signals.

[0053] The functional design of the outer shell plays a crucial role in ensuring the overall performance and reliability of the detection structure. In addition to protecting the internal detection coils from physical damage, chemical corrosion, and electromagnetic interference, the outer shell also undertakes the important task of ensuring the operation stability and long-term durability of the probe.

[0054] First of all, the design of the outer shell must consider the stability of contact with the power transmission line. This means that the outer shell should not only be strong but also have a certain elasticity to adapt to power transmission lines with different diameters and shapes, ensuring that there is always a tight and uniform contact between the coil and the power transmission line. The stability of this contact is crucial for the consistency and accuracy of the signal, and any loose or uneven contact may lead to signal distortion or attenuation.

[0055] During specific implementation, as a preferred implementation method, the outer shell is made of carbon fiber composite material.

[0056] In addition to considering insulation, corrosion resistance, and mechanical strength, the environmental adaptability and cost-effectiveness of the material also need to be considered. Carbon fiber composite materials have become an ideal choice due to their lightweight, high strength, and good chemical corrosion resistance. In addition, this material also has good thermal stability and electromagnetic shielding effects, which helps to reduce interference from external factors to the detection signal. The internal space of the housing should be customized according to the size and shape of the coil to ensure that the coils do not interfere with each other and at the same time reduce signal attenuation between the coil and the housing. The external dimensions of the housing should be designed to be compact and ergonomic for easy operation by the operator to carry and install, while considering its applicability in a narrow space. The housing design takes into account the requirements of easy maintenance and upgrade. Sufficient space and interfaces are reserved during the design for future upgrades or maintenance of the coil or signal processing unit. At the same time, the disassembly and assembly of the housing should be simple and fast to reduce maintenance time and cost. After the housing is manufactured, a series of performance tests are carried out, including pressure resistance tests, waterproof tests, impact resistance tests, etc. According to the test results, necessary improvements and optimizations are made to the housing. The housing design is shown in Figure (1).

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sensor device for detecting cable defects, characterized in that: include: Housing and detection structure, wherein: The housing has a detection structure disposed inside, which is used to fix the detection structure on the transmission line; The detection structure includes an excitation coil and a receiving coil, which are used to perform magnetic flux leakage detection and eddy current detection on the transmission line; The detection structure includes three excitation coils and three receiving coils, wherein: The angle between the three excitation coils is 120°, which divides the transmission line into three equal parts for generating a pulsed magnetic field; a receiving coil is arranged between two adjacent excitation coils, and the receiving coil is used to capture and analyze the magnetic field signal generated by the eddy current.

2. The sensor device for detecting cable defects according to claim 1, characterized in that: The housing comprises: a shell and a bracket, wherein: The shell is composed of three identical sector-shaped columns, and a mounting hole is provided on the shell. The mounting hole is coaxial with the shell, and the central axis of the shell completely coincides with the central axis of the mounting hole. The shell is a hollow cylindrical structure, and a bracket is arranged in the middle of the outer side of the fan-shaped column.

3. The sensor device for detecting cable defects according to claim 1, characterized in that: The detection structure also includes a shielding cover; The shielding cover is arranged on the upper part of the excitation coil to suppress the direct coupling between the excitation coil and the receiving coil and shield the interference signal.

4. The sensor device for detecting cable defects according to claim 1, characterized in that: The shell is made of carbon fiber composite material.

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