Grounding grid conductor defect position positioning method based on multiple side lines
By constructing a mathematical quantification model of the convex strength index CIn, the problem of relying on subjective human experience to locate the conductor defects in the grounding grid was solved. This enabled accurate location of conductor defects and efficient identification of early corrosion, promoting the intelligentization and standardization of grounding grid detection technology.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ELECTRIC POWER RES INST OF GUANGXI POWER GRID CO LTD
- Filing Date
- 2026-01-19
- Publication Date
- 2026-05-08
AI Technical Summary
In existing technologies, the location of defects in grounding grid conductors relies on subjective human experience and lacks objective quantitative standards, resulting in poor accuracy and consistency of detection results, which makes it difficult to meet the standardization and automation requirements of smart grids.
A multi-sided grounding grid conductor defect location method is adopted. By constructing a mathematical quantification model of the upward convexity strength index CIn, and combining the second derivative in the depth direction, the relative resistivity anomaly value, and the depth weighting function, the objectivity and automation of corrosion location are realized.
It has enabled accurate location of defects in grounding grid conductors, improved the ability to identify and locate early-stage minor corrosion, and promoted the development of grounding grid detection technology towards intelligence and standardization.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of grounding grid defect identification technology, and in particular to a method for locating the defect location of a grounding grid conductor based on multiple side wires. Background Technology
[0002] With the large-scale development of ultra-high voltage AC / DC hybrid power grids, grounding grids, as key facilities ensuring the safe and stable operation of power systems, are prone to defects such as discontinuities and corrosion thinning due to long-term underground conductor burial under the influence of soil corrosion, electrochemical corrosion, and fault current impacts. Traditional grounding grid detection methods, such as the high-current method and potential distribution method, require de-energization operations within operating substations and can only obtain the overall grounding resistance of the grounding grid, failing to accurately identify the specific location of hidden defects. Transient electromagnetic method (TEM), based on Faraday's law of electromagnetic induction, emits pulsed magnetic fields into the ground through a transmitting coil. Utilizing the significant electrical difference between the grounding grid conductor and the soil, it identifies low resistivity anomalies by inducing eddy currents and their secondary field attenuation characteristics. It has advantages such as non-contact operation, strong anti-interference, and high resolution, making it particularly suitable for grounding grid corrosion diagnosis in the complex electromagnetic environment of substations. However, a single measuring line can only obtain one-dimensional information in the profile direction, making it difficult to accurately locate corroded bodies in three-dimensional space. Therefore, multi-line fusion detection has become an inevitable direction for current technological development. Existing studies have verified that the corrosion area exhibits an "upward convexity" trend in the apparent resistivity profile, and this trend is more pronounced the closer the measurement line is to the corrosion center. However, the interpretation of multi-line data still relies on manual experience to compare the differences in profile morphology, lacking objective quantitative standards. As a result, the accuracy and consistency of the detection results are severely constrained by human subjective factors, making it difficult to meet the urgent needs of smart grids for standardized and automated detection equipment.
[0003] The core deficiency of existing technologies lies in the qualitative and subjective nature of corrosion anomaly identification. Specifically, engineers must visually observe the apparent resistivity profiles of multiple measuring lines, relying on subjective experience to determine which line exhibits a more pronounced upward convexity, thus inferring the location of corrosion. This method suffers from three serious drawbacks: First, the upward convexity trend lacks a mathematical definition, leading to potential disagreements among different personnel regarding the same profile, especially in the early stages of corrosion or against a background of uneven soil resistivity, where subtle anomalies are easily misjudged or missed. Second, the comparison of multiple measuring lines lacks a quantitative weighting mechanism, making it impossible to scientifically assess the relative contribution of each line's anomaly response. When multiple measuring lines show varying degrees of anomaly, it becomes difficult to accurately identify the line closest to the corrosion center. Third, manual interpretation is inefficient, hindering the rapid and automated processing of massive amounts of data, thus limiting the practical application of this method in large-scale, periodic inspections of grounding grids. These shortcomings directly increase the uncertainty of the location results, potentially masking early corrosion risks and leaving serious operational risks for substations.
[0004] Therefore, a method for locating defects in grounding grid conductors based on multi-side wires is needed. Summary of the Invention
[0005] To address the problems of existing technologies where multi-line corrosion assessment relies on subjective human experience and lacks objective quantitative standards, this invention provides a method for locating defects in grounding grid conductors based on multi-side wires. This method can construct an upward-convex strength index CI. n The mathematical quantification model fundamentally solves the problem of existing technologies relying on subjective experience for judgment. The specific technical solution is as follows: A method for locating defects in a grounding grid conductor based on multiple side wires, characterized by comprising the following steps; N test lines are arranged in the grounding grid detection area, and M test points are set at equal intervals on each test line; The induced voltage decay curves at each measuring point were acquired using the transient electromagnetic method. ; Convert the induced voltage into an apparent resistivity-time curve. ; Based on the smoke ring theory, a time-depth correspondence was established, and the apparent resistivity-time data was converted into an apparent resistivity-depth sequence. ; Calculate the convexity strength index of each survey line. The The following formula is used for quantification: In the formula, This represents the second derivative in the depth direction; Indicates the reference resistivity of a intact grounding grid; This represents the depth weighting function; Compare all survey lines Value, select The survey line corresponding to the maximum value is taken as the target survey line closest to the corrosion center; Extract the planar position coordinates of the defect on the target survey line. and depth coordinates ; Spatial cross-validation was performed using data from multiple survey lines to construct a three-dimensional confidence field. ,when If the value exceeds the preset threshold, the presence of a conductor defect in the area is confirmed, and the final location result is output.
[0006] Preferably, the three-dimensional confidence field is represented as follows: In the formula, Let n be the plane coordinates of the survey line. To determine the radius of influence of the survey line, This is a binary anomaly indicator function.
[0007] Preferably, the survey line layout satisfies: In the formula, d is the distance between the measuring lines, D is the width of the detection area, and h is the burial depth of the grounding grid.
[0008] The preferred formula for calculating the apparent resistivity is as follows: In the formula, Indicates apparent resistivity; Indicates the permeability of free space; Indicates the sampling time; Indicates the emitted magnetic moment; Indicates the equivalent area of the receiving coil; This represents the induced voltage.
[0009] Preferably, the time-depth correspondence is established based on the following formula: In the formula, Indicates the apparent depth of the probe; Indicates apparent resistivity. Represents the permeability of free space. Indicates diffusion time.
[0010] Preferably, the depth weighting function is as follows: In the formula, For target depth, The depth affects the half-width.
[0011] Preferably, the planar position coordinates of the defect are extracted on the target survey line. and depth coordinates The process is as follows: After determining the target survey line, the coordinates are then determined. ; Then, identify the measurement point corresponding to the maximum value of the second derivative integral on the target measurement line. : measuring point The horizontal coordinates represent the location of the defect plane. Defect depth coordinates The location is determined by the peak position of the second derivative in the depth direction of the measuring point.
[0012] A computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the multi-sided wire-based grounding grid conductor defect location method as described above.
[0013] A processor for running a program, wherein the program executes the method for locating defects in a grounding grid conductor based on multiple side wires as described above.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention constructs an upward convex strength index CI n The mathematical quantification model fundamentally solves the problem of existing technologies relying on subjective experience for judgment. This index innovatively integrates three layers of physical information: the second derivative in the depth direction quantitatively characterizes the degree of curve convexity, relative resistivity anomalies reflect the severity of corrosion, and a depth weighting function enhances the response contribution at the target burial depth, forming a unique numerical judgment standard. This upgrades the comparison of anomaly intensity from "visual observation" to "numerical ranking," realizing the objectification and automation of the entire corrosion location process. Simultaneously, the normalized confidence level P proposed in this invention... n With the three-dimensional confidence field C(x,y,z) mechanism, a mathematical framework for the scientific fusion of multi-line measurement data was established. This not only eliminated subjective human interference but also provided repeatable and verifiable quantitative results, significantly improving the identification and positioning accuracy of early weak corrosion under complex working conditions, and promoting the advancement of grounding grid detection technology towards intelligence and standardization. Attached Figure Description
[0015] (none). Detailed Implementation
[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0017] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.
[0018] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.
[0019] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.
[0020] In one embodiment of the present invention, a method for locating defects in a grounding grid conductor based on multiple side wires is provided, comprising the following steps: Step 1: Multiple measurement lines are arranged in the detection area, and several measurement lines are set up within the detection area: For example, N parallel or intersecting test lines (such as test line 1, test line 2, and test line 3) are evenly arranged in the target grounding grid area, with multiple test points set at equal intervals on each test line. The test line spacing d should satisfy d ≤ 2h (where h is the burial depth of the grounding grid) to ensure coverage of all grids to be tested. For multi-grid grounding grids (such as... (Grid), the survey line should span the grid center and key nodes.
[0021] Step 2: Conduct transient electromagnetic (TEM) detection along each survey line, as detailed below: The transmitting coil moves sequentially to each measuring point, transmitting a step current and then turning off; the receiving coil records the decay curve of the induced voltage V(t) over time. The acquired parameters include the transmitting magnetic moment M, the equivalent area S of the receiving coil, and the sampling time window t1~t2. n .
[0022] Key point: Due to the increased resistivity, the induced voltage decay characteristics of corroded areas differ from those of intact areas.
[0023] Step 3: Calculate the apparent resistivity value of each measuring point at different times to form the original data matrix, and convert the induced voltage-time data of each measuring point into an apparent resistivity-time curve. The formula for calculating the apparent resistivity is as follows: In the formula, Indicates apparent resistivity ( ), a function that changes with time, representing the equivalent resistivity of the underground medium at time t; This represents the free permeability, a constant value of 4π × 10⁻ 7 H / m describes the propagation characteristics of a magnetic field in a vacuum; The sampling time (s) is indicated by the time taken after the current is turned off, and it determines the detection depth. This represents the emitted magnetic moment (A·m²). The number of turns in the transmitting coil × current × area determines the transmitted energy. The equivalent area of the receiving coil (m²) is represented by S = Nᵣ·Aᵣ (number of turns of the receiving coil × area), which determines the signal receiving sensitivity. It represents the induced voltage (V), the transient electromagnetic attenuation signal measured by the receiving coil, and includes information on the resistivity of the underground medium.
[0024] Step 4: Establish the correspondence between time t and detection depth z: In the formula, The apparent depth (m) represents the effective penetration depth of the underground vortex ring at time t. Indicates apparent resistivity. Represents the permeability of free space. This represents the propagation time (s), the time it takes for an electromagnetic wave to travel underground.
[0025] Subsequently, the apparent resistivity-time curve obtained in step three is converted into an apparent resistivity-depth profile to provide depth coordinates for imaging.
[0026] Step 5: Perform spatial interpolation on all measurement point data for each measurement line to generate a two-dimensional apparent resistivity-depth profile. Intact areas: The center of the grid is concave, and the edges of the grid are convex. Corrosion zone: An abnormally enhanced "convex" trend appears at the edge of the corroded mesh. Pattern: The closer the test line is to the corrosion center, the more pronounced its upward convexity and the more significant the difference. For example, a two-dimensional profile is generated for each survey line n. And calculate the convexity strength index. : In the formula, It represents the second derivative in the depth direction, reflecting the strength of the curve's convexity; in the upper convex region, it is >0. The resistivity of the intact grounding grid is represented by the average value of the uncorroded area. This represents the depth weighting function, emphasizing the abnormal contribution at the target depth z0 (the burial depth of the grounding grid).
[0027] For example, the depth weighting function is as follows: In the formula, For the target depth, the design burial depth of the grounding grid is taken. The depth affects the half-width.
[0028] In short, The measurement line combines the degree of convexity, the magnitude of resistivity anomalies, and the correlation with depth. The larger the value, the closer the measurement line is to the corrosion center.
[0029] Step Six: Compare the CI value sequences of all survey lines. Determine the maximum value, and then determine the survey line closest to the corrosion center. : Simultaneously calculate the normalized confidence level: when When the value is greater than 0.4, it is determined that the measurement line n has a significant abnormal response.
[0030] Step 7: On the target survey line On the cross-section, identify the location of abnormal peaks: in, satisfy: This measuring point is the horizontal location where corrosion occurs.
[0031] Step 8: Use adjacent survey lines for cross-validation to construct a three-dimensional confidence field: In the formula, Let n be the plane coordinates of the survey line. To determine the radius of influence of the survey line, This is a binary anomaly indicator function. When voxels... When C > 0.75, it is confirmed as a corrosion defect.
[0032] Step 9: Output the final location result, including the coordinates of the defect center. and confidence level .
[0033] This invention constructs an upward convex strength index The mathematical quantification model fundamentally solves the problem of existing technologies relying on subjective experience for judgment. This index innovatively integrates three layers of physical information: the second derivative in the depth direction quantitatively characterizes the degree of curve convexity, the relative resistivity anomaly reflects the severity of corrosion, and the depth weighting function strengthens the response contribution at the target burial depth, forming a unique numerical judgment standard. This upgrades the comparison of anomaly intensity from "visual observation" to "numerical ranking," realizing the objectification and automation of the entire corrosion location process. Simultaneously, the normalized confidence level and three-dimensional confidence field proposed in this invention... The mechanism establishes a mathematical framework for the scientific fusion of multi-line measurement data, which not only eliminates subjective human interference but also provides repeatable and verifiable quantitative results. It significantly improves the identification and positioning accuracy of early weak corrosion under complex working conditions, and promotes the advancement of grounding grid detection technology towards intelligence and standardization.
[0034] Those skilled in the art will recognize that the units of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components of the various examples have been generally described in terms of functionality in the foregoing description. 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 the invention.
[0035] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical functional division. In actual implementation, there may be other division methods, such as multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored.
[0036] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.
[0037] If the integrated 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, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.
[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention 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 or all of the technical features therein. Such modifications or substitutions 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, and they should all be covered within the scope of the claims and specification of the present invention.
Claims
1. A method for locating defects in a grounding grid conductor based on multiple side wires, characterized in that, Includes the following steps; N test lines are arranged in the grounding grid detection area, and M test points are set at equal intervals on each test line; The induced voltage decay curves at each measuring point were acquired using the transient electromagnetic method. ; Convert the induced voltage into an apparent resistivity-time curve. ; Based on the smoke ring theory, a time-depth correspondence was established, and the apparent resistivity-time data was converted into an apparent resistivity-depth sequence. ; Calculate the convexity strength index of each survey line. The The following formula is used for quantification: In the formula, This represents the second derivative in the depth direction; Indicates the reference resistivity of a intact grounding grid; This represents the depth weighting function; Compare all survey lines Value, select The survey line corresponding to the maximum value is taken as the target survey line closest to the corrosion center; Extract the planar position coordinates of the defect on the target survey line. and depth coordinates ; Spatial cross-validation was performed using data from multiple survey lines to construct a three-dimensional confidence field. ,when If the value exceeds the preset threshold, the presence of a conductor defect in the area is confirmed, and the final location result is output.
2. The method for locating defects in a grounding grid conductor based on multiple side wires according to claim 1, characterized in that, The three-dimensional confidence field is represented as follows: In the formula, Let n be the plane coordinates of the nth survey line. To determine the radius of influence of the survey line, This is a binary anomaly indicator function.
3. The method for locating defects in a grounding grid conductor based on multiple side wires according to claim 1, characterized in that, The survey line layout satisfies: In the formula, d is the distance between the measuring lines, D is the width of the detection area, and h is the burial depth of the grounding grid.
4. The method for locating defects in a grounding grid conductor based on multiple side wires according to claim 1, characterized in that, The formula for calculating apparent resistivity is as follows: In the formula, Indicates apparent resistivity; Indicates the permeability of free space; Indicates the sampling time; Indicates the emitted magnetic moment; Indicates the equivalent area of the receiving coil; This represents the induced voltage.
5. The method for locating defects in a grounding grid conductor based on multiple side wires according to claim 1, characterized in that, The time-depth correspondence is established based on the following formula: In the formula, Indicates the apparent depth of the probe; Indicates apparent resistivity. Represents the permeability of free space. Indicates diffusion time.
6. The method for locating defects in a grounding grid conductor based on multiple side wires according to claim 1, characterized in that, The depth weighting function is as follows: In the formula, For target depth, The depth affects the half-width.
7. The method for locating defects in a grounding grid conductor based on multiple side wires according to claim 1, characterized in that, Extract the planar position coordinates of the defect on the target survey line. and depth coordinates The process is as follows: After determining the target survey line, the coordinates are then determined. ; Then, identify the measurement point corresponding to the maximum value of the second derivative integral on the target measurement line. : measuring point The horizontal coordinates represent the location of the defect plane. Defect depth coordinates The location is determined by the peak position of the second derivative in the depth direction of the measuring point.
8. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the computer-readable storage medium to perform the method for locating defects in a grounding grid conductor based on any one of claims 1 to 7.
9. A processor, characterized in that, The processor is used to run a program, wherein the program executes the method for locating the defect location of a grounding grid conductor based on any one of claims 1 to 7.