Substation secondary control cable path detection method and apparatus

Abstract

The application is suitable for the electric power technical field, and provides a substation secondary control cable path detection method and device. The substation secondary control cable path detection method comprises the following steps: injecting a detection signal into a substation secondary control cable; detecting a measured magnetic field distribution information at multiple positions in a preset area through a three-axis magnetic resistance sensor; comparing the measured magnetic field distribution information with theoretical magnetic field distribution information; and determining the path of the substation secondary control cable according to the matching condition of the measured magnetic field distribution information and the theoretical magnetic field distribution information. The application can realize the detection of the path of the substation secondary control cable, and the required labor cost and equipment cost are low.

Description

Technical Field

[0001] This application belongs to the field of power technology, and in particular relates to a method and device for detecting the path of secondary control cables in substations. Background Technology

[0002] In recent years, with the rapid development of urban construction, power cables have been widely used, and the workload of power cable maintenance has also increased. Due to unsatisfactory original power cable route data, the rapid changes in urban construction, and the adjustment of power cable maintenance personnel positions, the detection and identification of power cable routes have become an extremely important part of power cable maintenance work. If the power cable route cannot be clearly identified, the accident rate of damage to power cables during construction will increase; without knowing the specific route of the power cable, it is impossible to locate the fault point, affecting the speed of emergency repairs and the time required to restore power. Therefore, the detection of power cable routes has significant social and economic benefits.

[0003] Traditional power cable path detection is based on radio frequency identification (RFID) technology. This involves placing an electronic tag at regular intervals along the power cable, each tag containing relevant cable information. Workers then use a handheld reader to interact with the tags, reading the cable information and determining the cable's path based on this data.

[0004] However, traditional power cable path detection relies on multiple electronic tags pre-installed on the power cables, which require regular manual maintenance. This undoubtedly increases the labor and equipment costs required for power cable path detection significantly. Summary of the Invention

[0005] To overcome the problems existing in related technologies, embodiments of this application provide a method and apparatus for detecting the path of secondary control cables in substations.

[0006] This application is achieved through the following technical solution:

[0007] In a first aspect, embodiments of this application provide a method for detecting the path of secondary control cables in a substation, including:

[0008] Inject detection signals into the secondary control cables of the substation;

[0009] The measured magnetic field distribution information is obtained by detecting multiple positions in a preset area using a triaxial magnetoresistive sensor. The preset area is the area above the secondary control cable of the substation.

[0010] The measured magnetic field distribution information is compared with the theoretical magnetic field distribution information, which is the magnetic field distribution information obtained by experiment and at a preset vertical distance to the secondary control cable of the substation.

[0011] Based on the matching of the measured magnetic field distribution information with the theoretical magnetic field distribution information, the path of the secondary control cable of the substation is determined.

[0012] In conjunction with the first aspect, in some embodiments, the process of determining the theoretical magnetic field distribution information includes:

[0013] The control cable is modeled to obtain a control cable model, which contains the structural information of the control cable.

[0014] The laying environment of the control cable is modeled to obtain the laying environment model;

[0015] Based on the control cable model and the laying environment model, the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables are obtained.

[0016] The theoretical magnetic field distribution information is determined based on the first magnetic field distribution and the second magnetic field distribution.

[0017] In conjunction with the first aspect, in some embodiments, the structural information of the control cable includes the cable structure and material, the cable structure including conductor diameter, inner insulation thickness, inner sheath thickness, armor thickness and outer sheath thickness, and the material including conductor material, inner insulation material, inner sheath material, armor material and outer sheath material;

[0018] The laying environment model includes structural parameters of the laying environment; for the case where the control cable is laid in a cable tunnel, the structural parameters of the laying environment include tunnel width, tunnel height, number of cable support layers, support spacing, support width, and cable placement method; for the case where the control cable is laid underground, the structural parameters of the laying environment include soil, burial depth, and cable placement method.

[0019] In conjunction with the first aspect, in some embodiments, obtaining the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables includes:

[0020] The control cable model is meshed; wherein the mesh density on the surface of the cable core is greater than the mesh density inside the core, and the mesh is divided into any of the following patterns: triangle, quadrilateral, and six-node triangle.

[0021] Based on the meshed control cable model, the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables are obtained.

[0022] In conjunction with the first aspect, in some embodiments, the process of obtaining the first magnetic field distribution of the single control cable includes:

[0023] A three-phase power frequency alternating current of a preset magnitude is injected into the single control cable to obtain the first magnetic field distribution of the single control cable;

[0024] The first magnetic field distribution includes:

[0025] The magnetic field is strongest on the surface of phase A conductor. The magnetic field extremities of phase B and phase C conductors are located on the surface of conductors immediately adjacent to phase A conductors. The magnetic field distribution curve around the outer circumference of the single control cable is parabolic, with the strongest magnetic field distribution directly above the control cable. The magnetic field decreases as the path moves clockwise. The magnetic field distribution curve represents the change in magnetic induction intensity on a certain circumference outside the single control cable as the position gradually moves.

[0026] In conjunction with the first aspect, in some embodiments, the process of obtaining the second magnetic field distribution of the multiple control cables includes:

[0027] A three-phase power frequency AC current of a preset current magnitude is injected into each of the multiple control cables to obtain the second magnetic field distribution of the multiple control cables.

[0028] The second magnetic field distribution includes:

[0029] The magnetic induction intensity is mainly distributed inside the multiple control cables, while the magnetic induction intensity outside the multiple control cables is relatively small. The magnetic induction extremum is located at a certain position directly above the multiple control cables. The magnetic field distribution curve around the multiple control cables is parabolic, and the magnetic field distribution is strongest directly above the control cables. As the path moves clockwise, the magnetic field becomes smaller and smaller. The magnetic field distribution curve is the curve showing the change in the magnitude of the magnetic induction intensity on a certain circle outside the multiple control cables as the position gradually moves.

[0030] In conjunction with the first aspect, in some embodiments, the theoretical magnetic field distribution information includes:

[0031] The control cable includes an A-phase conductor, a B-phase conductor, a C-phase conductor, and a neutral conductor. The A-phase conductor is located above the neutral conductor, and the B-phase conductor and the C-phase conductor are located between the A-phase conductor and the neutral conductor. The A-phase conductor, B-phase conductor, C-phase conductor, and neutral conductor form a square, and the axis of the control cable is the center of this square.

[0032] The magnetic induction intensity generated by the three-phase conductor at point P, a predetermined distance above the control cable axis, is:

[0033]

[0034] The total magnetic field strength at point P is: B = B a -B b cosθ-B c cosθ;

[0035] Point P is located on the line connecting phase A conductor and neutral conductor, and is d away from the axis of the control cable; B a Let B be the magnetic flux density of phase A conductor at point P. b Let B be the magnetic flux density of phase B at point P. c Let μ0 be the magnetic flux density of the C-phase core at point P, μ0 be the free permeability, and R0 be the magnetic flux density. a R is the distance from point P to the conductor of phase A. b R is the distance from point P to the conductor of phase B. c Let I be the distance from point P to the C phase conductor. m Let θ be the current corresponding to the m-th phase conductor, where n is 3, the 1st phase corresponds to phase A, the 2nd phase corresponds to phase B, and the 3rd phase corresponds to phase C. θ is the angle between the line connecting point P to the axis of the control cable and the line connecting phase B conductor or phase C conductor to point P.

[0036] In conjunction with the first aspect, in some embodiments, the detection signal is a current of a preset magnitude and a frequency adjustable signal; wherein, as the frequency of the detection signal increases, the electromagnetic induction intensity decreases accordingly.

[0037] In conjunction with the first aspect, in some embodiments, determining the path of the substation secondary control cable based on the matching of the measured magnetic field distribution information and the theoretical magnetic field distribution information includes:

[0038] If the measured magnetic field distribution information at a certain location matches the theoretical magnetic field distribution information, then that location is determined to be a location in the secondary control cable path of the substation.

[0039] The path of the substation's secondary control cable is generated based on the locations where the measured magnetic field distribution information matches the theoretical magnetic field distribution information.

[0040] Secondly, embodiments of this application provide a substation secondary control cable path detection device, comprising:

[0041] The signal injection module is used to inject detection signals into the secondary control cables of the substation.

[0042] The magnetic field distribution detection module is used to detect the measured magnetic field distribution information at multiple locations in a preset area using a triaxial magnetoresistive sensor. The preset area is the path of the secondary control cable of the substation, which is initially determined. The vertical distance from the triaxial magnetoresistive sensor to the secondary control cable of the substation is a preset distance.

[0043] The magnetic field distribution comparison module is used to compare the measured magnetic field distribution information with the theoretical magnetic field distribution information. The theoretical magnetic field distribution information is the magnetic field distribution information obtained by experiments at a preset vertical distance to the secondary control cable of the substation.

[0044] The path determination module is used to determine the path of the substation secondary control cable based on the matching of the measured magnetic field distribution information and the theoretical magnetic field distribution information.

[0045] The beneficial effects of the embodiments in this application compared with the prior art are:

[0046] In this embodiment, a detection signal is injected into the secondary control cable of a substation. Then, a triaxial magnetoresistive sensor detects the measured magnetic field distribution information at multiple locations. The measured magnetic field distribution information is then compared with the theoretical magnetic field distribution information. Based on the matching of the measured magnetic field distribution information with the theoretical magnetic field distribution information, multiple locations in the path of the secondary control cable of the substation can be determined. Based on these multiple locations, the path of the secondary control cable of the substation can be determined, thereby enabling the detection of the path of the secondary control cable of the substation. Moreover, the required labor and equipment costs are relatively low.

[0047] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this specification. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a flowchart illustrating a substation secondary control cable path detection method according to an embodiment of this application;

[0050] Figure 2 This is a schematic diagram illustrating the magnetic field calculation principle of point P around the control cable provided in one embodiment of this application;

[0051] Figure 3 This is a simulation diagram of the cross-section of a control cable provided in an embodiment of this application;

[0052] Figure 4 This is a schematic diagram of a cable tunnel laying model provided in one embodiment of this application;

[0053] Figure 5 This is a schematic diagram of an underground cable laying model provided in one embodiment of this application;

[0054] Figure 6 This is an embodiment of the magnetic field distribution around the outer layer of a cable in the case of a single cable, as provided in this application.

[0055] Figure 7 This is a schematic diagram of the substation secondary control cable path detection device provided in the embodiments of this application. Detailed Implementation

[0056] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0057] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0058] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0059] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0060] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0061] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0062] Figure 1 This is a flowchart illustrating a substation secondary control cable path detection method according to an embodiment of this application. (Refer to...) Figure 1 The detailed method for detecting the secondary control cable path of this substation is as follows:

[0063] Step 101: Inject a detection signal into the secondary control cable of the substation.

[0064] For example, the detection signal can be a current of a preset size and a frequency adjustable signal.

[0065] In one scenario, when it is necessary to detect the path of a control cable, a detection signal can be injected into the control cable from the ground end, and then subsequent steps can be performed.

[0066] In another scenario, when it is necessary to detect the path of multiple control cables, a detection signal can be injected into each control cable at the ground end of each control cable, and then subsequent steps can be performed to determine the path of each control cable.

[0067] Step 102: The measured magnetic field distribution information is obtained by detecting multiple positions in a preset area using a triaxial magnetoresistive sensor. The preset area is the area above the secondary control cable of the substation.

[0068] For example, after injecting a detection signal into the control cable, the measured magnetic field distribution information can be obtained by using a triaxial magnetoresistive sensor in the area above the secondary control cable of the substation, thus obtaining the correspondence between the measured magnetic field distribution information and the detection position.

[0069] Step 103: Compare the measured magnetic field distribution information with the theoretical magnetic field distribution information. The theoretical magnetic field distribution information is the magnetic field distribution information obtained through experiments at a preset vertical distance to the secondary control cable of the substation.

[0070] In some embodiments, the process of determining the theoretical magnetic field distribution information may include: modeling the control cable to obtain a control cable model, the control cable model containing the structural information of the control cable; modeling the laying environment of the control cable to obtain a laying environment model; obtaining a first magnetic field distribution of a single control cable and a second magnetic field distribution of multiple control cables based on the control cable model and the laying environment model; and determining the theoretical magnetic field distribution information based on the first magnetic field distribution and the second magnetic field distribution.

[0071] The structural information of the control cable includes the cable structure and materials. The cable structure includes conductor diameter, inner insulation thickness, inner sheath thickness, armor thickness, and outer sheath thickness. The materials include the conductor material, inner insulation material, inner sheath material, armor material, and outer sheath material. The laying environment model includes the structural parameters of the laying environment. For the case where the control cable is laid in a cable tunnel, the structural parameters of the laying environment include tunnel width, tunnel height, number of cable support layers, support spacing, support width, and cable placement method. For the case where the control cable is laid underground, the structural parameters of the laying environment include soil conditions, burial depth, and cable placement method.

[0072] In some embodiments, obtaining the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables can specifically be achieved by: dividing the control cable model into a mesh; wherein the mesh density on the surface of the cable core is greater than the mesh density inside the core, and the mesh is divided into any of the following patterns: triangle, quadrilateral, or six-node triangle; based on the meshed control cable model, obtaining the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables.

[0073] After constructing the control cable model, it needs to be meshed. Mesh generation is closely related to simulation accuracy and computational efficiency. A coarse mesh results in low simulation accuracy but shorter computation time; a fine mesh results in high simulation accuracy but longer computation time. To balance accuracy and speed, mesh generation can be any pattern, such as triangular, quadrilateral, or six-node triangles.

[0074] Because control cables operate under power frequency AC voltage, the AC current generates a skin effect within the cable core, causing the magnetic field to concentrate on the surface layer. Therefore, a finer mesh is needed on the surface layer of the cable core, while the mesh within the core can be relatively smaller. This results in a mesh with a denser surface and a sparser interior. This meshing method for control cables balances simulation accuracy with computational efficiency.

[0075] For example, the process of obtaining the first magnetic field distribution of the single control cable includes: injecting a three-phase power frequency alternating current of a preset magnitude into the single control cable to obtain the first magnetic field distribution of the single control cable. The first magnetic field distribution includes: the magnetic field is largest on the surface of phase A conductor; the magnetic field extrema of phase B conductor and phase C conductor are located on the surface of the conductors adjacent to phase A conductor; the magnetic field distribution curve around the single control cable is parabolic, and the magnetic field distribution is strongest directly above the control cable, decreasing as the path moves clockwise; wherein, the magnetic field distribution curve is the curve showing the change in the magnitude of the magnetic induction intensity on a certain circle outside the single control cable as the position gradually moves.

[0076] For example, the process of obtaining the second magnetic field distribution of the multiple control cables includes: injecting a preset current of three-phase power frequency AC current into each of the multiple control cables to obtain the second magnetic field distribution of the multiple control cables. The second magnetic field distribution includes: the magnetic induction intensity is mainly distributed inside the multiple control cables, and the magnetic induction intensity outside the multiple control cables is relatively small; the magnetic induction extremum is located at a certain position directly above the multiple control cables; the magnetic field distribution curve around the multiple control cables is parabolic, and the magnetic field distribution is strongest directly above the control cables, decreasing as the path moves clockwise; wherein, the magnetic field distribution curve is the curve showing the change in the magnitude of the corresponding magnetic induction intensity on a certain circumference outside the multiple control cables as the position gradually moves.

[0077] For example, the control cable includes an A-phase core, a B-phase core, a C-phase core, and a neutral core, wherein the A-phase core is located above the neutral core, and the B-phase core and the C-phase core are located between the A-phase core and the neutral core. The A-phase core, B-phase core, C-phase core, and neutral core form a square, and the axis of the control cable is the center of this square.

[0078] The theoretical magnetic field distribution information includes:

[0079] The magnetic induction intensity generated by the three-phase conductor at point P, a predetermined distance above the control cable axis, is:

[0080]

[0081] The total magnetic field strength at point P is: B = B a -B b cosθ-B c cosθ;

[0082] Point P is located on the line connecting phase A conductor and neutral conductor, and is d away from the axis of the control cable; B aLet B be the magnetic flux density of phase A conductor at point P. b Let B be the magnetic flux density of phase B at point P. c Let μ0 be the magnetic flux density of the C-phase core at point P, μ0 be the free permeability, and R0 be the magnetic flux density. a R is the distance from point P to the conductor of phase A. b R is the distance from point P to the conductor of phase B. c Let I be the distance from point P to the C phase conductor. m Let θ be the current corresponding to the m-th phase conductor, where n is 3, the 1st phase corresponds to phase A, the 2nd phase corresponds to phase B, and the 3rd phase corresponds to phase C. θ is the angle between the line connecting point P to the axis of the control cable and the line connecting phase B conductor or phase C conductor to point P.

[0083] To simplify theoretical derivation and provide intuitive explanation, taking a control cable consisting of four cores (phase A, phase B, phase C, and neutral) as an example, a magnetic field calculation model for the control cable is constructed with the cable axis as the origin O, the magnetic field direction as the y-axis, and the direction from the cable axis to phase A as the x-axis. For example... Figure 2 As shown.

[0084] When performing magnetic field analysis on buried cables, because the cable's diameter is much smaller than its length, the cable must be considered as an infinitely long current-carrying straight conductor when analyzing its magnetic field distribution characteristics. According to the Biot-Sarvassi-Biscuit law, it is known that...

[0085]

[0086] Integrating over point P, we can derive a method for calculating the magnetic flux density B, i.e.

[0087]

[0088] Simplifying the above equation using trigonometric functions, and assuming the current-carrying straight conductor is infinitely long, we get:

[0089]

[0090] The magnetic flux density generated at point P is the vector superposition of the magnetic flux densities of each phase of the control cable acting individually at point P. The proportions of the magnetic flux densities generated by the three phase cores at point P are:

[0091]

[0092] The total magnetic induction intensity generated at point P is B = B a -B b cosθ-B c cosθ. Wherein... l b The distance from the B-phase conductor to the origin of the coordinate system is μ0, which can take the value of 4π × 10. -7 H / m.

[0093] Step 104: Determine the path of the substation secondary control cable based on the matching of the measured magnetic field distribution information and the theoretical magnetic field distribution information.

[0094] For example, step 104 can be implemented as follows: if the measured magnetic field distribution information at a certain location matches the theoretical magnetic field distribution information, then that location can be determined as a position in the path of the substation's secondary control cable. The path of the substation's secondary control cable can be obtained based on the locations where the measured magnetic field distribution information matches the theoretical magnetic field distribution information.

[0095] The aforementioned method for detecting the path of secondary control cables in substations involves injecting a detection signal into the secondary control cables, then using a triaxial magnetoresistive sensor to detect the measured magnetic field distribution information at multiple locations. This measured magnetic field distribution information is then compared with theoretical magnetic field distribution information. Based on the matching results, multiple locations within the path of the secondary control cables can be determined. This method enables the detection of the path of secondary control cables in substations, and it requires relatively low labor and equipment costs.

[0096] The following detailed explanation, with specific examples, illustrates how the theoretical magnetic field distribution information of the control cable is determined in the embodiments of this application.

[0097] To address the practical problems of limited transmission space and difficulty in path detection of control cables, this paper takes a four-core control cable as the research object and uses finite element analysis to study the magnetic field distribution characteristics and its influencing factors.

[0098] In this embodiment, Maxwell software is used to study the magnetic field distribution characteristics and its influencing factors. Maxwell software includes 2D and 3D solvers for transient magnetic fields, eddy current magnetic fields, static magnetic fields, transient electric fields, AC / DC transmitted electric fields, and electrostatic fields.

[0099] Maxwell software primarily studies the distribution characteristics of electromagnetic devices under three states (including static, steady-state, and transient) and two operating conditions (including normal operating conditions and fault operating conditions). It can also solve for the corresponding model parameters (including torque, capacitance, force, inductance, and impedance), and then automatically generate nonlinear equivalent circuits and state-space models to achieve comprehensive performance calculations at the system level.

[0100] When performing finite element simulation analysis on control cables, the first step is to select the appropriate solver based on the type of detection signal injected into the cable and the magnetic field it generates. Secondly, for control cables without a selected model, a model should be created, with parameters, material selection, and material properties chosen according to the actual control cables used in the project. After modeling, the required excitation and boundary conditions need to be applied to the model to make it as close as possible to the normal operating characteristics of the control cable. Furthermore, the model needs to be meshed to determine the accuracy of the calculations. Finally, the model is solved and the data is post-processed.

[0101] 1. Modeling of control cables and their laying environment

[0102] (1) Assumptions

[0103] In simulation modeling, the closer the model is to the actual on-site environment, the higher the simulation accuracy. However, due to the complexity of the environment and limited understanding, it is currently impossible to consider every minute disturbance factor. Therefore, before constructing the cable simulation model, the basic conditions are simplified and assumed as follows:

[0104] A. Both the operating frequency of the control cable and the frequency of the injected detection signal belong to the low-frequency range. In a low-frequency environment, the electric and magnetic fields have little interaction and can be regarded as independent research objects, that is, only the magnetic field distribution needs to be considered.

[0105] B. The operating environment of control cables is extremely complex, making it impossible to account for even the smallest interference factors when constructing simulation models of control cables. To facilitate this, the space where the control cable is located is usually defined as a circular air domain centered on the cable under test, and the radius of the air domain is much larger than the radius of the cable.

[0106] C. Cable tunnels are typically constructed of reinforced concrete, and the relative magnetic permeability of steel bars can reach 700, thus the reflection effect of the magnetic field within the tunnel walls on the tunnel space can be ignored. That is, when constructing a magnetic field simulation model for a cable tunnel, only the magnetic field distribution within the tunnel needs to be considered.

[0107] (2) Cable body modeling

[0108] Control cables are commonly used in power plants, substations, and other power hubs in control circuits with rated voltages of 600V or 1000V and below. They connect secondary equipment and integrated automation devices to ensure the stable and continuous operation of the entire power supply system. This embodiment uses a commonly used 4-core copper-core cross-linked polyethylene insulated, PVC-sheathed, shielded control cable in power distribution networks as a model. Figure 3 As shown.

[0109] Control cables are typically over 1 kilometer in length. Since their diameter is much smaller than their length, they can be considered as an infinitely long uniform conductor in theoretical analysis. That is, the magnetic field of the cable changes only in the radial direction and not in the axial direction. Therefore, a 2D model is sufficient for the research needs when constructing a simulation model of the control cable's magnetic field.

[0110] For example, the structural parameters of the control cable include conductor diameter, inner insulation thickness, inner sheath thickness, armor thickness, outer sheath thickness, as well as the materials of the conductor, inner insulation, inner sheath, armor, and outer sheath, and the relative permeability of the conductor, inner insulation, inner sheath, armor, and outer sheath, as shown in Table 1.

[0111] Table 1 Structural parameters of control cables

[0112] conductor diameter 1.8 copper 1 Inner insulation thickness 0.7 Cross-linked polyethylene 1 Inner sheath thickness 0.4 Polyvinyl chloride 1 Armor thickness 0.2 copper 1 Outer sheath thickness 1.2 Polyvinyl chloride 1

[0113] After constructing the control cable model, it needs to be meshed. Mesh generation is closely related to simulation accuracy and computational efficiency. A coarse mesh results in low simulation accuracy but shorter computation time; a fine mesh results in high simulation accuracy but longer computation time. To balance accuracy and speed, mesh generation can be any pattern, such as triangular, quadrilateral, or six-node triangles.

[0114] Because control cables operate under power frequency AC voltage, the AC current generates a skin effect within the cable core, causing the magnetic field to concentrate on the surface layer. Therefore, a finer mesh is needed on the surface layer of the cable core, while the mesh within the core can be relatively smaller. This results in a mesh with a denser surface and a sparser interior. This meshing method for control cables balances simulation accuracy with computational efficiency.

[0115] (2) Laying environment modeling

[0116] When simulating the overall working environment of control cables, it is necessary to model the overall working environment of control cables, as there are many factors in the actual laying environment of control cables, such as cable tunnels, that may affect the distribution of the magnetic field of the cable.

[0117] Control cables carry low voltages of 1000V and below, therefore no intervals are required when laying them. There are various methods for laying control cables; this embodiment studies the more typical and commonly used methods of cable tunnel laying and underground cable laying.

[0118] Cable tunnels are typically located underground in power plants and substations. Cable supports are installed on both sides of the tunnel, usually with 2 to 4 layers, depending on the tunnel's height. The height between each layer should be at least 800 mm. The supports are usually made of stainless steel, which is resistant to corrosion. Control cables are laid on the supports. Because control cables carry relatively small currents and there are generally no distance requirements between them, multiple layers are allowed, but the coverage of the supports should not exceed their allowable capacity. Based on these requirements, a 1:1 model of a cable tunnel in an actual traction substation is created, and the tunnel structure parameters are shown in Table 2.

[0119] Table 2 Tunnel structural parameters

[0120] 2000 2300 3 800 700

[0121] In the cable tunnel model, control cables are placed on the middle and lower supports, laid without spacing between them. Each support layer holds five control cables. Figure 4 As shown.

[0122] In the underground cable model, the cable is buried at a depth of 0.7 meters, with 5 adjacent control cables and no spacing between them. Figure 5 As shown.

[0123] The cable tunnel wall structure contains materials such as reinforcing steel, which can easily interfere with magnetic fields. However, the control cable is a low-voltage cable with a low voltage level, so the reinforcing steel in the wall is insufficient to affect the magnetic field and can be ignored. The cable support is made of stainless steel, which will not interfere with the distribution of the magnetic field strength around the cable during the magnetic field strength study. When the control cable is buried underground, the relative magnetic permeability of the soil is set at 1.

[0124] 2. Power frequency magnetic field distribution of control cables under natural characteristics

[0125] (1) Single cable case

[0126] In the simulation model, a three-phase power frequency AC current (detection signal) with an effective value of 1A is injected into the control cable. The magnetic induction intensity of the three-phase single cable under natural characteristics follows the following rules: the magnetic field on the surface of the A phase conductor is the largest, and the extreme value can reach 6009.3μT; the extreme values ​​of the magnetic field of the B phase linear and C phase conductors are located on the surface of the conductors that are close to the A phase conductor, and the magnetic induction intensity can reach 5113.2μT.

[0127] The reasons for the above two distribution patterns are as follows: the skin effect of the conductor core makes the magnetic field strength gradually increase from the inside to the outside, that is, the surface of the conductor core is the strongest and the inside of the conductor core is the weakest; the proximity effect of the conductor core makes the magnetic field strength tend to be at the connection between the two conductor cores.

[0128] To further investigate the magnetic field distribution around the cable, a path was taken around the outer edge of the cable sheath, starting from the leftmost point of the cable and proceeding clockwise around the circumference. The magnetic field conditions at various locations along this path were obtained, such as... Figure 6 As shown.

[0129] Depend on Figure 6 It can be seen that the magnetic field distribution around the control cable follows the following pattern: the magnetic field distribution around the cable is approximately parabolic; the magnetic field distribution is strongest directly above the cable, and the magnetic field becomes smaller as the path moves clockwise.

[0130] (2) Multiple cable situations

[0131] exist Figure 4 The multiple control cables shown are simultaneously injected with a three-phase AC current of 1A. Simulation results show that the magnetic field strength during operation is mainly distributed inside the cables, while the external magnetic field is relatively small. Since the external magnetic field is much smaller than the internal magnetic field, its influence is ignored in this embodiment.

[0132] Establish a horizontal path 30mm above the cable, determine the magnetic field distribution along this horizontal path, and calculate the analytical and numerical results of the magnetic field distribution along the horizontal path.

[0133] The calculation results show the following patterns between the numerical and analytical calculations of the magnetic field distribution along the horizontal path: the two results are basically consistent, and both exhibit the same trend, showing a parabolic distribution; the magnetic field extremes both occur at a certain position directly above the cable, with the peak value of the analytical calculation being 112.34 μT and the peak value of the numerical calculation being 111.51 μT. The discrepancy between the analysis results under the two conditions is mainly due to the fact that when modeling the control cable, its shielding material was set to pure copper with a permeability of 1, which is more ideal than reality. When the difference in magnetic induction intensity between the two is on the order of 10... -7 T can be ignored in actual calculations.

[0134] 3. Ideal magnetic field distribution characteristics during signal injection

[0135] Different signal injection methods lead to varying accuracy in control cable path detection. Common signal injection methods include core injection, armor layer injection, and induction. This embodiment focuses on core injection. Regarding the selection of the injected signal, the magnetic flux density B is directly related to the amplitude of the injected signal current; a larger current amplitude results in a stronger magnetic flux density and a more pronounced parabolic distribution. The following uses a sinusoidal signal with an injected current amplitude of 1A and a frequency of 1kHz as the reference signal.

[0136] (1) Core injection status

[0137] A reference signal is injected into phase A conductor. The grounding terminal at the end of phase A conductor, the grounding terminal of the path detection device, and the cable form a closed loop. Due to the skin effect generated when AC current flows through the cable, the magnetic field at the conductor is distributed at the edge between the conductor and the inner insulation layer, where the magnetic induction intensity is the greatest, reaching 222.47 μT. Furthermore, the magnetic field diffuses outward from conductor A as the center; the larger the diffusion radius, the smaller the magnetic induction intensity.

[0138] The maximum magnetic field strength generated after the reference signal is injected into the cable under test is 222.47 μT, while the maximum power frequency magnetic field strength of the adjacent cable in the cable tunnel can reach 6009.3 μT. Compared with the two, the former is smaller in magnitude, and the magnetic field distribution of the former is not obvious in the cloud map.

[0139] To accurately analyze the changes in the magnetic field around the cable under test before and after the injection of a reference signal, a certain circumference outside the cable sheath was selected as the research object. The magnetic induction intensity of the cable under test was determined when it was de-energized and when the reference signal was injected into the core, and the two were compared. The changes in magnetic induction intensity around the outer ring of the cable under both conditions showed the following patterns: the trend of magnetic induction intensity change was consistent (both were W-shaped), and the magnetic induction intensity was the highest at the zero point and 17.5 mm of the circumference; the energized cable under test and the inductively energized cable under test had the same magnetic field direction at the same spatial location point, and the magnetic induction intensity on the conductor connection line could reach 310 μT, which was slightly higher than that when the cable under test was de-energized; the maximum magnetic induction intensity generated by the reference signal around the outer ring of the cable under test was only on the order of one ten-thousandth of a Tesla. The penetrating power of a magnetic field of this magnitude is very weak and unlikely to cause any damage to nearby control cables.

[0140] (2) Distribution of surrounding magnetic field at different frequencies

[0141] Magnetic field strength is closely related to frequency; the higher the frequency, the shorter the wavelength of the electromagnetic wave, and the greater the energy loss during transmission. Furthermore, the greater the induced electromotive force, the stronger the eddy currents. The attenuation law of frequency signals in the electromagnetic domain is studied below. The injected signal transmission frequencies are set to 500Hz, 5kHz, 50kHz, and 500kHz, and the magnetic induction intensity of the four frequency bands at a position 0.7 meters directly above the cable is determined.

[0142] Simulation results show that if only the frequency of the injected signal is changed, the magnetic flux density around the control cable changes slightly as the frequency increases, but the overall trend conforms to the basic laws of Maxwell's equations; as the frequency of the injected signal increases, the slight magnetic flux density further decreases.

[0143] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0144] Corresponding to the substation secondary control cable path detection method described in the above embodiments, Figure 7 The diagram shows a structural block diagram of a substation secondary control cable path detection device provided in an embodiment of this application. For ease of explanation, only the parts related to the embodiment of this application are shown.

[0145] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0146] See Figure 7 The substation secondary control cable path detection device in this embodiment may include a signal injection module 201, a magnetic field distribution detection module 202, a magnetic field distribution comparison module 203, and a path determination module 204.

[0147] The signal injection module 201 is used to inject detection signals into the secondary control cables of the substation.

[0148] The magnetic field distribution detection module 202 is used to detect the measured magnetic field distribution information at multiple locations in a preset area using a triaxial magnetoresistive sensor. The preset area is the path of the secondary control cable of the substation that is initially determined, and the vertical distance from the triaxial magnetoresistive sensor to the secondary control cable of the substation is a preset distance.

[0149] The magnetic field distribution comparison module 203 is used to compare the measured magnetic field distribution information with the theoretical magnetic field distribution information. The theoretical magnetic field distribution information is the magnetic field distribution information obtained by experimental determination at a preset vertical distance to the secondary control cable of the substation.

[0150] The path determination module 204 is used to determine the path of the substation secondary control cable based on the matching of the measured magnetic field distribution information and the theoretical magnetic field distribution information.

[0151] Optionally, the process of determining the theoretical magnetic field distribution information includes:

[0152] The control cable is modeled to obtain a control cable model, which contains the structural information of the control cable.

[0153] The laying environment of the control cable is modeled to obtain the laying environment model;

[0154] Based on the control cable model and the laying environment model, the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables are obtained.

[0155] The theoretical magnetic field distribution information is determined based on the first magnetic field distribution and the second magnetic field distribution.

[0156] Optionally, the structural information of the control cable includes the cable structure and material. The cable structure includes the conductor diameter, inner insulation thickness, inner sheath thickness, armor thickness, and outer sheath thickness. The material includes the conductor material, inner insulation material, inner sheath material, armor material, and outer sheath material.

[0157] The laying environment model includes structural parameters of the laying environment; for the case where the control cable is laid in a cable tunnel, the structural parameters of the laying environment include tunnel width, tunnel height, number of cable support layers, support spacing, support width, and cable placement method; for the case where the control cable is laid underground, the structural parameters of the laying environment include soil, burial depth, and cable placement method.

[0158] Optionally, obtaining the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables may include:

[0159] The control cable model is meshed; wherein the mesh density on the surface of the cable core is greater than the mesh density inside the core, and the mesh is divided into any of the following patterns: triangle, quadrilateral, and six-node triangle.

[0160] Based on the meshed control cable model, the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables are obtained.

[0161] Optionally, the process of obtaining the first magnetic field distribution of the single control cable includes:

[0162] A three-phase power frequency alternating current of a preset magnitude is injected into the single control cable to obtain the first magnetic field distribution of the single control cable;

[0163] The first magnetic field distribution includes:

[0164] The magnetic field is strongest on the surface of phase A conductor. The magnetic field extremities of phase B and phase C conductors are located on the surface of conductors immediately adjacent to phase A conductors. The magnetic field distribution curve around the outer circumference of the single control cable is parabolic, with the strongest magnetic field distribution directly above the control cable. The magnetic field decreases as the path moves clockwise. The magnetic field distribution curve represents the change in magnetic induction intensity on a certain circumference outside the single control cable as the position gradually moves.

[0165] Optionally, the process of obtaining the second magnetic field distribution of the multiple control cables includes:

[0166] A three-phase power frequency AC current of a preset current magnitude is injected into each of the multiple control cables to obtain the second magnetic field distribution of the multiple control cables.

[0167] The second magnetic field distribution includes:

[0168] The magnetic induction intensity is mainly distributed inside the multiple control cables, while the magnetic induction intensity outside the multiple control cables is relatively small. The magnetic induction extremum is located at a certain position directly above the multiple control cables. The magnetic field distribution curve around the multiple control cables is parabolic, and the magnetic field distribution is strongest directly above the control cables. As the path moves clockwise, the magnetic field becomes smaller and smaller. The magnetic field distribution curve is the curve showing the change in the magnitude of the magnetic induction intensity on a certain circle outside the multiple control cables as the position gradually moves.

[0169] Optionally, the theoretical magnetic field distribution information includes:

[0170] The control cable includes an A-phase conductor, a B-phase conductor, a C-phase conductor, and a neutral conductor. The A-phase conductor is located above the neutral conductor, and the B-phase conductor and the C-phase conductor are located between the A-phase conductor and the neutral conductor. The A-phase conductor, B-phase conductor, C-phase conductor, and neutral conductor form a square, and the axis of the control cable is the center of this square.

[0171] The magnetic induction intensity generated by the three-phase conductor at point P, a predetermined distance above the control cable axis, is:

[0172]

[0173] The total magnetic field strength at point P is: B = B a -B b cosθ-B c cosθ;

[0174] Point P is located on the line connecting phase A conductor and neutral conductor, and is d away from the axis of the control cable; B a Let B be the magnetic flux density of phase A conductor at point P. b Let B be the magnetic flux density of phase B at point P. c Let μ0 be the magnetic flux density of the C-phase core at point P, μ0 be the free permeability, and R0 be the magnetic flux density. a R is the distance from point P to the conductor of phase A. b R is the distance from point P to the conductor of phase B. c Let I be the distance from point P to the C phase conductor. m Let m be the line connecting point P to the axis of the control cable and the line connecting phase B or phase C to point P.

[0175] Optionally, the detection signal is a current of a preset magnitude and a frequency adjustable signal; wherein, as the frequency of the detection signal increases, the electromagnetic induction intensity decreases accordingly.

[0176] For example, the path determination module can be used to: if the measured magnetic field distribution information at a certain location matches the theoretical magnetic field distribution information, then determine that location as a location in the path of the substation secondary control cable; generate the path of the substation secondary control cable based on the locations where the measured magnetic field distribution information matches the theoretical magnetic field distribution information.

[0177] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0178] Those skilled in the art will recognize that the templates, units, and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0179] If the module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above embodiments of the substation secondary control cable path detection method. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0180] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for detecting the path of secondary control cables in a substation, characterized in that, include: Inject detection signals into the secondary control cables of the substation; The measured magnetic field distribution information is obtained by detecting multiple positions in a preset area using a triaxial magnetoresistive sensor. The preset area is the area above the secondary control cables of the substation. The measured magnetic field distribution information is compared with the theoretical magnetic field distribution information, which is the magnetic field distribution information obtained by experiment and at a preset vertical distance to the secondary control cable of the substation. Based on the matching of the measured magnetic field distribution information with the theoretical magnetic field distribution information, the path of the secondary control cable of the substation is determined; The process of determining the theoretical magnetic field distribution information includes: The control cable is modeled to obtain a control cable model, which contains the structural information of the control cable. The laying environment of the control cable is modeled to obtain the laying environment model; Based on the control cable model and the laying environment model, the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables are obtained. The process of obtaining the first magnetic field distribution of the single control cable includes: A three-phase power frequency alternating current of a preset magnitude is injected into the single control cable to obtain the first magnetic field distribution of the single control cable; The first magnetic field distribution includes: The magnetic field is strongest on the surface of phase A conductor. The magnetic field extremities of phase B and phase C conductors are located on the surface of the conductors immediately adjacent to phase A conductors. The magnetic field distribution curve around the outer circumference of the single control cable is parabolic, with the strongest magnetic field distribution directly above the control cable. The magnetic field decreases as the path moves clockwise. The magnetic field distribution curve represents the change in magnetic induction intensity on a certain circumference outside the single control cable as the position gradually moves. The process of obtaining the second magnetic field distribution of the multiple control cables includes: A three-phase power frequency AC current of a preset current magnitude is injected into each of the multiple control cables to obtain the second magnetic field distribution of the multiple control cables. The second magnetic field distribution includes: The magnetic induction intensity is mainly distributed inside the multiple control cables, while the magnetic induction intensity outside the multiple control cables is relatively small. The magnetic induction extremum is located at a certain position directly above the multiple control cables. The magnetic field distribution curve around the multiple control cables is parabolic, and the magnetic field distribution is strongest directly above the control cables. As the path moves clockwise, the magnetic field becomes smaller and smaller. The magnetic field distribution curve is the curve showing the change in the magnitude of the magnetic induction intensity on a certain circle outside the multiple control cables as the position gradually moves. The theoretical magnetic field distribution information is determined based on the first magnetic field distribution and the second magnetic field distribution; The acquisition of the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables includes: The control cable model is meshed; wherein the mesh density on the surface of the cable core is greater than the mesh density inside the core, and the mesh is divided into any of the following patterns: triangle, quadrilateral, and six-node triangle. Based on the meshed control cable model, the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables are obtained.

2. The substation secondary control cable path detection method as described in claim 1, characterized in that, The structural information of the control cable includes the cable structure and material. The cable structure includes the conductor diameter, inner insulation thickness, inner sheath thickness, armor thickness, and outer sheath thickness. The material includes the conductor material, inner insulation material, inner sheath material, armor material, and outer sheath material. The laying environment model includes structural parameters of the laying environment; for the case where the control cable is laid in a cable tunnel, the structural parameters of the laying environment include tunnel width, tunnel height, number of cable support layers, support spacing, support width, and cable placement method; for the case where the control cable is laid underground, the structural parameters of the laying environment include soil, burial depth, and cable placement method.

3. The substation secondary control cable path detection method as described in claim 1, characterized in that, The theoretical magnetic field distribution information includes: The control cable includes an A-phase conductor, a B-phase conductor, a C-phase conductor, and a neutral conductor. The A-phase conductor is located above the neutral conductor, and the B-phase conductor and the C-phase conductor are located between the A-phase conductor and the neutral conductor. The A-phase conductor, B-phase conductor, C-phase conductor, and neutral conductor form a square, and the axis of the control cable is the center of this square. The magnetic induction intensity generated by the three-phase conductor at point P, a predetermined distance above the control cable axis, is: ； The total magnetic field strength at point P is: ; Point P is located on the line connecting phase A conductor and neutral conductor, and is d away from the axis of the control cable. B a Let be the magnetic flux density of phase A conductor at point P. B b Let be the magnetic flux density of phase B conductor at point P. B c Let be the magnetic flux density of the C-phase conductor at point P. The permeability of free space, Let P be the distance from point P to the conductor of phase A. Let P be the distance from point P to phase B conductor. Let P be the distance from point P to the C-phase conductor. For the first m The current corresponding to the phase conductor core n The number is 3, with the first phase corresponding to phase A, the second phase to phase B, and the third phase to phase C. The angle between the line connecting point P to the axis of the control cable and the line connecting phase B or phase C to point P.

4. The substation secondary control cable path detection method as described in claim 1, characterized in that, The detection signal is a current of a preset magnitude and a frequency that is adjustable; wherein, as the frequency of the detection signal increases, the electromagnetic induction intensity decreases accordingly.

5. The substation secondary control cable path detection method as described in claim 1, characterized in that, The step of determining the path of the substation secondary control cable based on the matching information between the measured magnetic field distribution and the theoretical magnetic field distribution includes: If the measured magnetic field distribution information at a certain location matches the theoretical magnetic field distribution information, then that location is determined to be a location in the secondary control cable path of the substation. The path of the substation's secondary control cable is generated based on the locations where the measured magnetic field distribution information matches the theoretical magnetic field distribution information.

6. A substation secondary control cable path detection device, characterized in that, include: The signal injection module is used to inject detection signals into the secondary control cables of the substation. The magnetic field distribution detection module is used to detect and obtain measured magnetic field distribution information at multiple locations in a preset area using a triaxial magnetoresistive sensor; the preset area is the area above the secondary control cable of the substation. The magnetic field distribution comparison module is used to compare the measured magnetic field distribution information with the theoretical magnetic field distribution information. The theoretical magnetic field distribution information is the magnetic field distribution information obtained by experiments at a preset vertical distance to the secondary control cable of the substation. The path determination module is used to determine the path of the substation secondary control cable based on the matching of the measured magnetic field distribution information and the theoretical magnetic field distribution information. The magnetic field distribution comparison module is also used to model the control cable to obtain a control cable model, which contains the structural information of the control cable. The laying environment of the control cable is modeled to obtain the laying environment model; Based on the control cable model and the laying environment model, the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables are obtained. The process of obtaining the first magnetic field distribution of the single control cable includes: A three-phase power frequency alternating current of a preset magnitude is injected into the single control cable to obtain the first magnetic field distribution of the single control cable; The first magnetic field distribution includes: The magnetic field is strongest on the surface of phase A conductor. The magnetic field extremities of phase B and phase C conductors are located on the surface of the conductors immediately adjacent to phase A conductors. The magnetic field distribution curve around the outer circumference of the single control cable is parabolic, with the strongest magnetic field distribution directly above the control cable. The magnetic field decreases as the path moves clockwise. The magnetic field distribution curve represents the change in magnetic induction intensity on a certain circumference outside the single control cable as the position gradually moves. The process of obtaining the second magnetic field distribution of the multiple control cables includes: A three-phase power frequency AC current of a preset current magnitude is injected into each of the multiple control cables to obtain the second magnetic field distribution of the multiple control cables. The second magnetic field distribution includes: The magnetic induction intensity is mainly distributed inside the multiple control cables, while the magnetic induction intensity outside the multiple control cables is relatively small. The magnetic induction extremum is located at a certain position directly above the multiple control cables. The magnetic field distribution curve around the multiple control cables is parabolic, and the magnetic field distribution is strongest directly above the control cables. As the path moves clockwise, the magnetic field becomes smaller and smaller. The magnetic field distribution curve is the curve showing the change in the magnitude of the magnetic induction intensity on a certain circle outside the multiple control cables as the position gradually moves. The theoretical magnetic field distribution information is determined based on the first magnetic field distribution and the second magnetic field distribution; The magnetic field distribution comparison module is also used for The control cable model is meshed; wherein the mesh density on the surface of the cable core is greater than the mesh density inside the core, and the mesh is divided into any of the following patterns: triangle, quadrilateral, and six-node triangle. Based on the meshed control cable model, the first magnetic field distribution of a single control cable and the second magnetic field distribution of multiple control cables are obtained.

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