A grounding grid positioning and state identification method and system based on multi-device detection
By constructing a three-dimensional resistivity model of the grounding grid using a multi-device detection method, the problems of low detection efficiency and large error in existing grounding grid technologies are solved, achieving efficient and accurate grounding grid positioning and status identification, thus ensuring the safety of the power system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- STATE GRID JIANGSU ELECTRIC POWER CO XUZHOU POWER SUPPLY CO
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-29
Smart Images
Figure CN122109908A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of grounding grid technology, specifically relating to a grounding grid location and status identification method and system based on multi-device detection. Background Technology
[0002] The design, installation, and maintenance of grounding grids for transmission towers are fundamental to ensuring the safe operation of high-voltage transmission lines and systems. As an independently buried, concealed device, the quality of the grounding grid's construction directly affects the long-term safe and stable operation of the transmission lines. During the construction phase, accurately detecting the actual physical state of the grounding grid (including conductor diameter and other morphological characteristics, burial depth, planar position, layout shape, resistance, etc.) is a necessary measure to avoid a decline in construction quality and ensure the safe operation of the grounding grid.
[0003] Most power transmission lines are erected in the field using poles and towers, making them highly susceptible to lightning strikes, which can compromise the safety and stability of the power grid. Grounding grids discharge lightning and fault currents when equipment is struck by lightning or experiences a malfunction, ensuring stable ground potential and thus guaranteeing the safe operation of the power system. However, because grounding grids are underground for extended periods, they are easily affected by moisture, soil pH levels, and other harmful gases, leading to corrosion and breakage. If these problems are not detected promptly, they can result in poor grounding grid performance and ineffective lightning protection, threatening equipment and personnel safety.
[0004] To ensure the stable operation of the power system, power inspection departments should regularly inspect and evaluate the performance parameters of the grounding grid on transmission towers. This presents challenges in inspecting the construction quality during the installation of the grounding grid and in its long-term maintenance. Currently, the inspection of the grounding grid's construction status and performance parameters mainly relies on manual excavation. This method is not only labor-intensive and inefficient, but also easily limited by the site environment, making it difficult to accurately locate the grounding grid's position and quality. While existing technologies use transient electromagnetic devices for grounding grid positioning, single-monitoring methods result in significant errors in both location and condition identification. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a method and system for locating and identifying the status of a grounding grid based on multi-device detection. This method can accurately locate the position of the grounding grid and precisely identify its spatial distribution characteristics and status based on its actual burial depth, without power outages or excavation.
[0006] This invention provides the following technical solution:
[0007] Firstly, a method for locating and identifying the status of a grounding grid based on multi-device detection is provided, comprising the following steps: Through experiments and numerical simulations, the three-component electromagnetic response characteristics of the grounding grid round steel under different soil types, burial depths, diameters, and corrosion levels were obtained, and a database was constructed. The grounding grid was detected by the multi-turn small loop transient electromagnetic method and the equivalent reverse flux transient electromagnetic method, respectively, to obtain data reflecting the deep and shallow distribution characteristics of the grounding grid. The three-component electromagnetic response characteristics of the grounding grid round steel in the database are introduced as constraints. After fusing the mid-deep and shallow distribution characteristic data of the grounding grid, a three-dimensional resistivity model of the grounding grid is constructed through an inversion algorithm. Based on the obtained three-dimensional resistivity model, the grounding grid is located according to the spatial morphology of the low resistivity anomaly. Combined with the database, the state of the grounding grid is identified by analyzing the changes in the resistivity value, continuity and geometric characteristics of the anomaly.
[0008] Optionally, the construction of the database specifically includes: Construct a grounding grid model, delineate the solution domain space, and define the two media, air and soil, as well as the electromagnetic parameters of the two media. Under ideal simulation conditions, keeping other variables constant, the grounding grid model is simulated by changing one variable in turn to obtain pure secondary field induced voltage data; the variables are soil type, burial depth, diameter, and degree of corrosion. After processing and characterizing the secondary field induced voltage data from multiple simulations, the three-component electromagnetic response characteristics of the grounding grid round steel are obtained, forming a database.
[0009] Optionally, based on the multi-turn small loop device, the grounding grid is detected by the multi-turn small loop transient electromagnetic method. The multi-turn small loop device includes: a first receiving coil and a first transmitting coil wound with a multi-turn conductor plane. The method of using a multi-turn small loop transient electromagnetic method to detect the grounding grid involves: passing a stable DC transmitting current into the first transmitting coil to generate a stable primary magnetic field; instantaneously turning off the transmitting current to generate a secondary magnetic field in the grounding grid, which passes through the first receiving coil, causing the first receiving coil to receive the induced voltage decay curve that changes with time, and using it as deep distribution characteristic data in the grounding grid.
[0010] Optionally, the first transmitting coil has a diameter of 0.6m, 100 turns, and a transmitting current of not less than 10A; the second receiving coil has a diameter of 0.3m and 100 turns.
[0011] Optionally, based on an equivalent anti-magnetic flux device, the equivalent anti-magnetic flux transient electromagnetic method is used to detect the grounding grid. The equivalent anti-magnetic flux device is a transceiver integrated anti-magnetic flux antenna. The transceiver integrated anti-magnetic flux antenna includes: an integrated transmitting source and a second receiving coil. The transmitting source consists of two identical multi-turn second transmitting coils placed vertically parallel and strictly coaxially, and the two second transmitting coils are connected in series with the transmitter in opposite directions. The second receiving coil is located in the middle of the two multi-turn transmitting coils. The equivalent transmitting area of the transmitting source is 400m × 400m. The method of using equivalent reverse flux transient electromagnetic method to detect the grounding grid is as follows: a stable DC transmitting current is supplied to the transmitting source to generate a stable primary magnetic field. When the transmitting current is turned off, the primary field change of the receiving coil is zero. The second receiving coil receives the induced voltage decay curve that changes with time and uses it as the shallow distribution characteristic data of the grounding grid.
[0012] Optionally, based on an equivalent reverse magnetic flux device, the equivalent reverse magnetic flux transient electromagnetic method is used to detect the grounding grid. The equivalent reverse magnetic flux device is a center loop device; the center loop device includes a multi-turn planar coil; the equivalent area of the multi-turn planar coil is not less than 400 m². 2 The resonant frequency is greater than 200kHz, and the receiving sampling rate is 625KHz; The method of using equivalent reverse flux transient electromagnetic method to detect the grounding grid is as follows: During the transmission phase, a transmission current is passed into a multi-turn planar coil, which generates a stable primary magnetic field. When the current is turned off, the multi-turn planar coil switches to the receiving mode and receives the induced voltage decay curve that changes over time, using it as the shallow distribution characteristic data of the grounding grid.
[0013] Optionally, the deep and shallow distribution characteristic data of the grounding grid are fused, specifically as follows: The actual burial depth of the grounding grid is obtained, and the distribution characteristic data of the medium-deep layer and the shallow layer of the grounding grid are weighted and fused based on the burial depth using corresponding weights. Specifically: when the burial depth of the grounding grid is less than 0.5m, the weight of the shallow layer distribution characteristic data is 1, and the weight of the medium-deep layer distribution characteristic data is 0; when the burial depth of the grounding grid is between 0.5m and 1m, the weight of both the shallow layer distribution characteristic data and the medium-deep layer distribution characteristic data is 0.5; when the burial depth of the grounding grid is between 1m and 1.5m, the weight of the shallow layer distribution characteristic data is 0.25, and the weight of the medium-deep layer distribution characteristic data is 0.75; when the burial depth of the grounding grid exceeds 1.5m, the weight of the shallow layer distribution characteristic data is 0, and the weight of the medium-deep layer distribution characteristic data is 1.
[0014] Secondly, a grounding grid location and status identification system based on multi-device detection is provided, including: Database: Stores the three-component electromagnetic response characteristics of the grounding grid round steel under different soil types, burial depths, diameters, and corrosion levels; Multi-turn small loop device: The grounding grid is detected by the transient electromagnetic method of multi-turn small loop to obtain data reflecting the deep distribution characteristics of the grounding grid; Equivalent anti-magnetic flux device: The equivalent anti-magnetic flux transient electromagnetic method is used to detect the grounding grid and obtain data reflecting the shallow distribution characteristics of the grounding grid; Fusion Inversion Module: The three-component electromagnetic response characteristics of the grounding grid round steel in the database are introduced as constraints. After fusing the medium-deep and shallow distribution characteristic data of the grounding grid, a three-dimensional resistivity model of the grounding grid is constructed through the inversion algorithm. Location and Status Identification Module: Based on the obtained three-dimensional resistivity model, the grounding grid is located according to the spatial morphology of the low resistivity anomaly. Combined with the database, the status of the grounding grid is identified by analyzing the changes in resistivity value, continuity and geometric characteristics of the anomaly.
[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention studies the three-component electromagnetic response characteristics of grounded round steel under different conditions through experimental research and numerical simulation, and constructs a corresponding database, providing a theoretical basis for detecting and identifying grounding using transient electromagnetic methods. It also fully utilizes the cross-referencing and verification of transient electromagnetic detection methods of different device types, which not only more effectively reveals the underground distribution characteristics of the grounding grid but also reduces false anomalies caused by interference. This invention employs a three-dimensional resistivity model for locating and identifying the state of the grounding grid, supporting arbitrary directional cutting (longitudinal, transverse, or horizontal sections), and can truly reflect the three-dimensional morphology of underground targets. It avoids the deviations caused by the two-dimensional interpretation of existing technologies, which can only present a single section, and has high accuracy. Compared with existing technologies, it has advantages such as high work efficiency, strong objectivity, low cost, and environmental friendliness. It can avoid economic losses and personnel waste caused by excavation and power outage detection, prevent power accidents, and ensure the safe operation of the power system. Attached Figure Description
[0016] Figure 1 This is a flowchart of the grounding grid location and status identification method based on multi-device detection of the present invention; Figure 2 This is a schematic diagram of the grounding grid topology structure built when constructing the database in this invention; Figure 3 This invention provides a multi-track profile obtained using the equivalent reverse magnetic flux transient electromagnetic method when the steel bar is buried at a depth of 0.6m. Figure 4 This invention provides a multi-track profile obtained using the multi-turn small loop transient electromagnetic method when the steel reinforcement is buried at a depth of 0.8m. Figure 5 This is a multi-track profile obtained by using the multi-turn small loop transient electromagnetic method when the actual detection depth of the reinforcing steel is 0.6m. Detailed Implementation
[0017] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be used to limit the scope of protection of the present invention. It should be noted that the term "comprising" and any variations thereof in the specification, claims and the above-mentioned drawings of the present invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or devices.
[0018] Example 1 like Figure 1 As shown, a grounding grid location and status identification method based on multi-device detection includes the following steps: Step S1: Obtain the three-component electromagnetic response characteristics of the grounding grid round steel under different soil types, burial depths, diameters, and corrosion levels through experiments and numerical simulations, and construct a database; Step S2: The grounding grid is detected by the multi-turn small loop transient electromagnetic method and the equivalent reverse flux transient electromagnetic method respectively, to obtain data reflecting the deep and shallow distribution characteristics of the grounding grid; Step S3: Introduce the three-component electromagnetic response characteristics of the grounding grid round steel in the database as a constraint condition. After fusing the mid-deep and shallow distribution characteristic data of the grounding grid, construct a three-dimensional resistivity model of the grounding grid through an inversion algorithm. Step S4: Based on the obtained three-dimensional resistivity model, the grounding grid is located according to the spatial morphology of the low resistivity anomaly. Combined with the database, the state of the grounding grid is identified by analyzing the changes in the resistivity value, continuity and geometric characteristics of the anomaly.
[0019] In step S1, the database is constructed, which specifically includes: A grounding grid model is constructed, the solution domain is defined, and the electromagnetic parameters of the air and soil layers are defined. Under ideal simulation conditions, while keeping other variables constant, the grounding grid model is simulated by changing one variable in turn to obtain pure secondary field induced voltage data. The variables are soil type, burial depth, diameter, and degree of corrosion. After processing and characterizing the secondary field induced voltage data from multiple simulations, the three-component electromagnetic response characteristics of the grounding grid round steel are obtained and a database is formed.
[0020] In this embodiment, as in this embodiment, Figure 2 As shown, the grounding grid model has a specification of 2×2, with each grid having a side length of 4m, and a total grounding grid area of 8m×8m. It is buried 0.8m underground, and the electrical conductivity of the round steel material is 1×10⁻⁶. 7 The solution domain has a cross-sectional diameter of 10 mm, a relative permeability of 4000, and a relative permittivity of 1 (S / m). The upper layer is the solution domain for the air layer, and the lower layer is the solution domain for the soil layer. The total size of the solution domain is a cube of 50 m × 50 m × 100 m. Since soil and air are both non-magnetic materials, their permeability is similar to that in vacuum, so their permeability is set to the vacuum permeability. H / m, the electrical conductivity of soil is 0.01 S / m, and the electrical conductivity of air is set to... S / m.
[0021] Under ideal simulation conditions, relatively pure secondary field induced voltage data can be obtained. However, in actual operating conditions, considering the precision of the instrument, electromagnetic interference, and other limitations, the linear interruption of the transmitting current is not maintained indefinitely. It is difficult for the instrument to fully capture both signals, making pure secondary field induced voltage data challenging to obtain. Therefore, this application only analyzes the signal after the transmitting current is completely turned off. Based on the distribution of magnetic induction intensity, it is possible to infer which grounding grids the coil is strongly coupled to, and thus determine the topology of the grounding grid.
[0022] In this embodiment, step S2 specifically includes: S21: Based on the multi-turn small loop device, the transient electromagnetic method of the multi-turn small loop is used to detect the grounding grid and obtain the deep distribution characteristic data of the grounding grid.
[0023] S22: Based on the equivalent anti-magnetic flux device, the equivalent anti-magnetic flux transient electromagnetic method is used to detect the grounding grid and obtain shallow distribution characteristic data of the grounding grid.
[0024] The multi-turn small loop device in step S21 includes: a first receiving coil and a first transmitting coil wound in a plane with multiple turns of wire; the first transmitting coil has a diameter of 0.6m, 100 turns, and a transmitting current of not less than 10A; the second receiving coil has a diameter of 0.3m and 100 turns. The distance between measuring points can be selected according to actual needs.
[0025] Step S21 specifically involves: supplying a stable DC transmitting current to the first transmitting coil to generate a stable primary magnetic field; then, momentarily cutting off the transmitting current, causing the grounding grid to generate a secondary magnetic field. This secondary magnetic field passes through the first receiving coil, resulting in the first receiving coil receiving a time-varying induced voltage decay curve. This induced voltage decay curve received by the first receiving coil is used as deep distribution characteristic data in the grounding grid. More specifically, firstly, a DC current is supplied to the first transmitting coil on the ground, and then the power is suddenly cut off. The current in the first transmitting coil will undergo a sudden change, and this transient current will generate a transient magnetic field in space. This transient magnetic field induces eddies underground, which continuously diffuse underground over time. The diffusion rate is related to the resistivity of the underground strata, and the eddies diffuse to different depths at different times. We achieve the purpose of understanding the underground resistivity by recording the changes in underground eddies (i.e., the magnetic field change rate in dB / dT).
[0026] The equivalent anti-magnetic flux device in step S22 is either a transceiver integrated anti-magnetic flux antenna or a center loop device.
[0027] The transceiver anti-magnetic flux antenna includes: an integrated transmitting source and a second receiving coil. The transmitting source consists of two identical multi-turn second transmitting coils placed vertically and strictly coaxially, and the two second transmitting coils are connected in series with the transmitter in opposite directions. The second receiving coil is located in the middle of the two multi-turn transmitting coils. The equivalent transmitting area of the transmitting source is 400m×400m.
[0028] When the equivalent anti-magnetic flux device is a transceiver integrated anti-magnetic flux antenna, step S22 specifically involves: supplying a stable DC transmitting current to the transmitting source to generate a stable primary magnetic field. When the transmitting current is turned off, the primary field change of the receiving coil is zero. The second receiving coil receives the induced voltage attenuation curve that changes over time, and uses this induced voltage attenuation curve as the shallow distribution characteristic data of the grounding grid. On the plane directly between the two coils, the two magnetic fields precisely cancel each other out, forming a zero flux plane, where the second receiving coil is located. When the current is turned off, the primary field change at the receiving point is zero, therefore the received signal almost completely avoids the direct interference of the turn-off process, directly reflecting the pure early secondary field generated by the underground conductor.
[0029] The center loop device includes a multi-turn planar coil (square or round); the equivalent area of the multi-turn planar coil is not less than 400m². 2 The resonant frequency is greater than 200kHz, and the receiving sampling rate is 625KHz.
[0030] When the equivalent reverse magnetic flux device is a center loop device, step S22 is as follows: During the transmission phase, a transmission current is passed into the multi-turn planar coil, and the multi-turn planar coil generates a stable primary magnetic field. When the current is turned off, the multi-turn planar coil switches to the receiving mode and receives the induced voltage attenuation curve that changes with time. The voltage attenuation curve received by the multi-turn planar coil is used as the shallow distribution characteristic data of the grounding grid.
[0031] In this embodiment, in step S3, the deep and shallow distribution feature data of the grounding grid are fused. Specifically, the actual burial depth of the grounding grid is obtained, and the deep and shallow distribution feature data of the grounding grid are weighted and fused based on the burial depth using corresponding weights.
[0032] When the grounding grid is buried at a depth of less than 0.5m, the weight of shallow distribution characteristic data is 1, and the weight of medium-deep distribution characteristic data is 0, meaning that the data mainly relies on the equivalent reverse flux device, providing more accurate results within the depth range. When the grounding grid is buried at a depth of 0.5m to 1m, the weights of both shallow and medium-deep distribution characteristic data are 0.5. When the grounding grid is buried at a depth of 1m to 1.5m, the weight of shallow distribution characteristic data is 0.25, and the weight of medium-deep distribution characteristic data is 0.75. When the grounding grid is buried at a depth of more than 1.5m, the weight of shallow distribution characteristic data is 0, and the weight of medium-deep distribution characteristic data is 1. Fusion of medium-deep and shallow distribution characteristic data from the grounding grid effectively integrates the advantages of both detection technologies and improves the accuracy and reliability of the overall detection results.
[0033] In step S3, the three-dimensional resistivity model can be constructed using existing software by running inversion algorithms such as least squares or Bayesian inversion. Through iterative processes, the resistivity value of each volume element in the three-dimensional space is continuously adjusted until the model response best fits the measured data. The observed data is a fusion of mid-to-deep and shallow layer distribution characteristic data. When constructing the three-dimensional resistivity model, a rough initial three-dimensional resistivity model needs to be established based on regional geological data (such as soil structure and bedrock depth) and known information (such as grounding grid design drawings). Then, the knowledge from the database is used as constraints, such as the known dimensions and burial depth of the grounding round steel and its typical electromagnetic response characteristics under different corrosion levels, for inversion.
[0034] In this embodiment, step S3 specifically involves: normalizing and fusing the decoded multi-turn small loop transient electromagnetic and equivalent anti-magnetic flux transient electromagnetic data, with the two complementing and verifying each other to form a three-dimensional resistivity scatter plot. Then, based on the size of the study area, boundary and terrain files are generated first. Next, based on the actual burial depth of the grounding grid, a suitable bottom interface depth (generally 1-3m) is selected, and a three-dimensional structural model is generated by integrating the boundary files. The next step is to partition the three-dimensional structural model according to the specific conditions of the study area, setting the mesh size and horizontal (vertical) resolution. Since the diameter of the grounding grid reinforcement is relatively thin, the mesh size should not be too large (usually 0.05-0.2m). Finally, the three-dimensional resistivity scatter plot can be imported into the structural model, and attribute modeling is performed using a discrete smooth interpolation algorithm to calculate the resistivity corresponding to each cell. By observing the resistivity distribution characteristics and combining them with simulation results, the distribution characteristics and state of the grounding grid can be accurately identified. Discrete smooth interpolation algorithms can refer to existing technologies. Specifically, Discrete Smooth Interpolation (DSI) is an interpolation method based on polynomial functions and regularization constraints. Its core principle is to minimize the weighted sum of data fitting error and curvature penalty term, so as to ensure that the interpolation curve passes through discrete data points while suppressing the oscillation problem (such as Runge phenomenon) common in high-order polynomial interpolation.
[0035] In step S4, the grounding grid is located based on the spatial morphology of the low resistivity anomaly, and the state of the grounding grid is identified by analyzing the changes in the resistivity value, continuity and geometric characteristics of the anomaly in conjunction with the database. This can be done with reference to existing technologies.
[0036] In the three-dimensional resistivity model, a low resistivity threshold is set. Based on this threshold, all adjacent grid cells with resistivity below this threshold in three-dimensional space are connected, outlined, and rendered into an independent three-dimensional entity. This entity is the located grounding grid. By extracting its spatial information such as direction, length, burial depth, and connection nodes, precise positioning can be achieved, and a three-dimensional structural diagram can be drawn. The state of the grounding grid is identified by corrosion or breakage. For example, if the resistivity value of a conductor segment is significantly higher than the intact state value calibrated in the database, but the shape is still roughly continuous, it is judged as corrosion. If a low-resistivity body that should be continuous experiences obvious discontinuity or breakage in three-dimensional space, with the resistivity rising sharply at the cross-section to match the surrounding soil background, it is judged as breakage.
[0037] For grounding grid detection data, a real-world scenario was reproduced through numerical simulation. A magnetic emission source was used as the transmitting source (note: multi-turn small loop and equivalent reverse magnetic flux are both magnetic emission sources), and loop reception was used as the receiving method. Two scenarios were simulated: rebar burial depths of 0.6m and 0.8m, with the rebar located at the center of the measuring line in both cases. Figure 3 and Figure 4 It can be seen that the reinforcing bars at the center of the measuring line all exhibit significant responses. Therefore, the use of a multi-turn small-loop device combined with the equivalent reverse flux transient electromagnetic method for detecting the grounding grid provides a strong theoretical basis. Furthermore, reinforcing bars with a diameter of 13mm were buried at a depth of 0.6m underground, and detection was performed using a multi-turn small-loop transient electromagnetic device and the equivalent reverse flux transient electromagnetic method. Taking the multi-turn small-loop device as an example, the multi-channel profile obtained after data processing (such as...) Figure 5 As shown, the presence of abnormal reinforcing bars is clearly reflected. Therefore, both the multi-turn small-loop transient electromagnetic method and the equivalent reverse flux transient electromagnetic method can be used to effectively detect the grounding grid. Subsequently, the multi-track profiles of multiple measuring points will be fused into a reliable three-dimensional resistivity model through an inversion algorithm, which will greatly improve the positioning accuracy and status identification accuracy of the grounding grid.
[0038] Example 2 A grounding grid location and status identification system based on multi-device detection includes: Database: Stores the three-component electromagnetic response characteristics of the grounding grid round steel under different soil types, burial depths, diameters, and corrosion levels; Multi-turn small loop device: The grounding grid is detected by the transient electromagnetic method of multi-turn small loop to obtain data reflecting the deep distribution characteristics of the grounding grid; Equivalent anti-magnetic flux device: The equivalent anti-magnetic flux transient electromagnetic method is used to detect the grounding grid and obtain data reflecting the shallow distribution characteristics of the grounding grid; Fusion Inversion Module: The three-component electromagnetic response characteristics of the grounding grid round steel in the database are introduced as constraints. After fusing the medium-deep and shallow distribution characteristic data of the grounding grid, a three-dimensional resistivity model of the grounding grid is constructed through the inversion algorithm. Location and Status Identification Module: Based on the obtained three-dimensional resistivity model, the grounding grid is located according to the spatial morphology of the low resistivity anomaly. Combined with the database, the status of the grounding grid is identified by analyzing the changes in resistivity value, continuity and geometric characteristics of the anomaly.
[0039] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatuses disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section. Those skilled in the art will clearly understand that the technologies in the embodiments of this invention can be implemented using software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions in the embodiments of this invention, in essence or the parts that contribute to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or certain parts of the embodiments of this invention.
[0040] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.
Claims
1. A method for locating and identifying the status of a grounding grid based on multi-device detection, characterized in that, Includes the following steps: Through experiments and numerical simulations, the three-component electromagnetic response characteristics of the grounding grid round steel under different soil types, burial depths, diameters, and corrosion levels were obtained, and a database was constructed. The grounding grid was detected by the multi-turn small loop transient electromagnetic method and the equivalent reverse flux transient electromagnetic method, respectively, to obtain data reflecting the deep and shallow distribution characteristics of the grounding grid. The three-component electromagnetic response characteristics of the grounding grid round steel in the database are introduced as constraints. After fusing the mid-deep and shallow distribution characteristic data of the grounding grid, a three-dimensional resistivity model of the grounding grid is constructed through an inversion algorithm. Based on the obtained three-dimensional resistivity model, the grounding grid is located according to the spatial morphology of the low resistivity anomaly. Combined with the database, the state of the grounding grid is identified by analyzing the changes in the resistivity value, continuity and geometric characteristics of the anomaly.
2. The grounding grid location and status identification method based on multi-device detection according to claim 1, characterized in that, The construction of the database specifically includes: Construct a grounding grid model, delineate the solution domain space, and define the two media, air and soil, as well as the electromagnetic parameters of the two media. Under ideal simulation conditions, keeping other variables constant, the grounding grid model is simulated by changing one variable in turn to obtain pure secondary field induced voltage data; the variables are soil type, burial depth, diameter, and degree of corrosion. After processing and characterizing the secondary field induced voltage data from multiple simulations, the three-component electromagnetic response characteristics of the grounding grid round steel are obtained, forming a database.
3. The grounding grid location and status identification method based on multi-device detection according to claim 1, characterized in that, Based on the multi-turn small loop device, the grounding grid is detected by the multi-turn small loop transient electromagnetic method. The multi-turn small loop device includes: a first receiving coil and a first transmitting coil wound with a multi-turn conductor in a plane. The method of using a multi-turn small loop transient electromagnetic method to detect the grounding grid involves: passing a stable DC transmitting current into the first transmitting coil to generate a stable primary magnetic field; instantaneously turning off the transmitting current to generate a secondary magnetic field in the grounding grid, which passes through the first receiving coil, causing the first receiving coil to receive the induced voltage decay curve that changes with time, and using it as deep distribution characteristic data in the grounding grid.
4. The grounding grid location and status identification method based on multi-device detection according to claim 3, characterized in that, The first transmitting coil has a diameter of 0.6m, 100 turns, and a transmitting current of not less than 10A; the second receiving coil has a diameter of 0.3m and 100 turns.
5. The grounding grid location and status identification method based on multi-device detection according to claim 1, characterized in that, Based on the equivalent anti-magnetic flux device, the equivalent anti-magnetic flux transient electromagnetic method is used to detect the grounding grid. The equivalent anti-magnetic flux device is a transceiver integrated anti-magnetic flux antenna. The transceiver anti-magnetic flux antenna includes: an integrated transmitting source and a second receiving coil. The transmitting source consists of two identical multi-turn second transmitting coils placed vertically parallel and strictly coaxially, and the two second transmitting coils are connected in series with the transmitter in opposite directions. The second receiving coil is located in the middle of the two multi-turn transmitting coils. The equivalent transmitting area of the transmitting source is 400m × 400m. The method of using equivalent reverse flux transient electromagnetic method to detect the grounding grid is as follows: a stable DC transmitting current is supplied to the transmitting source to generate a stable primary magnetic field. When the transmitting current is turned off, the primary field change of the receiving coil is zero. The second receiving coil receives the induced voltage decay curve that changes with time and uses it as the shallow distribution characteristic data of the grounding grid.
6. The grounding grid location and status identification method based on multi-device detection according to claim 1, characterized in that, Based on an equivalent reverse magnetic flux device, the equivalent reverse magnetic flux transient electromagnetic method is used to detect the grounding grid. The equivalent reverse magnetic flux device is a center loop device; the center loop device includes a multi-turn planar coil; the equivalent area of the multi-turn planar coil is not less than 400 m². 2 The resonant frequency is greater than 200kHz, and the receiving sampling rate is 625KHz; The method of using equivalent reverse flux transient electromagnetic method to detect the grounding grid is as follows: During the transmission phase, a transmission current is passed into a multi-turn planar coil, which generates a stable primary magnetic field. When the current is turned off, the multi-turn planar coil switches to the receiving mode and receives the induced voltage decay curve that changes over time, using it as the shallow distribution characteristic data of the grounding grid.
7. The grounding grid location and status identification method based on multi-device detection according to claim 1, characterized in that, The distribution characteristic data of the grounding grid in the middle and deep layers and the distribution characteristic data in the shallow layer are fused together, specifically as follows: The actual burial depth of the grounding grid is obtained, and the distribution characteristic data of the medium-deep layer and the shallow layer of the grounding grid are weighted and fused based on the burial depth using corresponding weights. Specifically: when the burial depth of the grounding grid is less than 0.5m, the weight of the shallow layer distribution characteristic data is 1, and the weight of the medium-deep layer distribution characteristic data is 0; when the burial depth of the grounding grid is between 0.5m and 1m, the weight of both the shallow layer distribution characteristic data and the medium-deep layer distribution characteristic data is 0.5; when the burial depth of the grounding grid is between 1m and 1.5m, the weight of the shallow layer distribution characteristic data is 0.25, and the weight of the medium-deep layer distribution characteristic data is 0.75; when the burial depth of the grounding grid exceeds 1.5m, the weight of the shallow layer distribution characteristic data is 0, and the weight of the medium-deep layer distribution characteristic data is 1.
8. A grounding grid location and status identification system based on multi-device detection, characterized in that, include: Database: Stores the three-component electromagnetic response characteristics of the grounding grid round steel under different soil types, burial depths, diameters, and corrosion levels; Multi-turn small loop device: The grounding grid is detected by the transient electromagnetic method of multi-turn small loop to obtain data reflecting the deep distribution characteristics of the grounding grid; Equivalent anti-magnetic flux device: The equivalent anti-magnetic flux transient electromagnetic method is used to detect the grounding grid and obtain data reflecting the shallow distribution characteristics of the grounding grid; Fusion Inversion Module: The three-component electromagnetic response characteristics of the grounding grid round steel in the database are introduced as constraints. After fusing the medium-deep and shallow distribution characteristic data of the grounding grid, a three-dimensional resistivity model of the grounding grid is constructed through the inversion algorithm. Location and Status Identification Module: Based on the obtained three-dimensional resistivity model, the grounding grid is located according to the spatial morphology of the low resistivity anomaly. Combined with the database, the status of the grounding grid is identified by analyzing the changes in resistivity value, continuity and geometric characteristics of the anomaly.