Lightning protection device current leakage detection method and system

Abstract

The application provides a lightning protection device current leakage detection method and system. First, the equivalent uniform field response signal corresponding to the rotating electromagnetic field at different rotating moments is determined, and the surface of the lightning protection device is divided into multiple current detection blocks. The field strength coupling relationship between the surface of the lightning protection device and the detection probe in the detection probe array is determined from the equivalent uniform field response signal corresponding to the rotating moment. The density inversion field of the current on the surface of the lightning protection device at the rotating moment is determined through the field strength coupling relationship combined with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotating moment. The current density topology of the lightning protection device leakage current is generated based on all the density inversion fields, and then the leakage current position of the lightning protection device is located from the current density abnormal area in the current density topology. The application can reduce the influence of the complex geometric structure of the lightning protection device on the spatial positioning of the surface leakage current.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of current leakage detection, and more particularly, to a lightning protection device current leakage detection method and system. BACKGROUND

[0002] Current leakage detection is a crucial technology in the field of electrical safety, and its core purpose is to identify the current that does not flow along the intended path in an electrical system (i.e., leakage current), thereby preventing electric shock, fire, equipment damage, and other safety accidents.

[0003] Lightning protection devices (such as lightning rods, down conductors, etc.) are exposed to harsh environments for a long time, and are prone to insulation performance degradation due to material aging, structural damage, or loose connections, which can cause leakage current. Traditional detection methods (such as ground resistance measurement, infrared thermal imaging) have obvious limitations: it is difficult to accurately locate small leakage points, and it is greatly affected by environmental interference; especially on devices with complex geometries, it is difficult to visualize the density distribution of leakage current, resulting in ambiguous hazard location and low maintenance efficiency. Existing electromagnetic detection technology can sense current, but lacks response analysis capability for rotating dynamic excitation, and does not establish a current density inversion model combined with device geometric characteristics, resulting in insufficient leakage point identification accuracy, which cannot meet the operation and maintenance needs of high-reliability protection systems. Therefore, how to reduce the influence of the complex geometry of lightning protection devices on the spatial positioning of surface leakage current has become a problem in the industry. SUMMARY

[0004] The present application provides a lightning protection device current leakage detection method and system, which can reduce the influence of the complex geometry of lightning protection devices on the spatial positioning of surface leakage current.

[0005] In a first aspect, the present application provides a lightning protection device current leakage detection method, wherein a rotating electromagnetic field detection probe array is deployed near the lightning protection device, and a controllable rotating electromagnetic field is applied to the detection area of the lightning protection device during detection. The method comprises the following steps:

[0006] Collecting electromagnetic field response signals of the detection probe array under rotating excitation;

[0007] Decomposing the electromagnetic field response signals into equivalent uniform field response signals corresponding to different rotation instants of the rotating electromagnetic field, and dividing the surface of the lightning protection device into multiple current detection blocks based on the geometric structure information of the lightning protection device;

[0008] For each rotation moment, the induced field strength of each current detection block is calculated based on the equivalent uniform field response signal corresponding to the rotation moment, and then the field strength coupling relationship between the surface of the lightning protection device and the detection probe in the detection probe array is formed, and the current density of the surface of the lightning protection device is inversely calculated based on the field strength coupling relationship and the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment, so as to obtain the density inversion field of the current of the surface of the lightning protection device at the rotation moment, and then the density inversion field of the current of the surface of the lightning protection device at each rotation moment is obtained.

[0009] Based on all the density inversion fields, the current density topological map of the leakage current of the lightning protection device is generated, and then the leakage current position of the lightning protection device is located from the current density abnormal area in the current density topological map.

[0010] In some embodiments, decomposing the electromagnetic field response signal into the equivalent uniform field response signals corresponding to different rotation moments of the rotating electromagnetic field specifically includes:

[0011] Obtaining different rotation moments of the rotating electromagnetic field;

[0012] Selecting one rotation moment as a selected rotation moment, and extracting an electromagnetic field response signal segment corresponding to the selected rotation moment from the electromagnetic field response signal;

[0013] Determining the equivalent uniform field response signal corresponding to the selected rotation moment of the rotating electromagnetic field according to the electromagnetic field response signal segment;

[0014] Continuing to determine the equivalent uniform field response signals corresponding to the remaining rotation moments of the rotating electromagnetic field.

[0015] In some embodiments, dividing the surface of the lightning protection device into a plurality of current detection blocks based on the geometric structure information of the lightning protection device specifically includes:

[0016] Obtaining the geometric structure information of the lightning protection device;

[0017] Determining the surface division principle of the lightning protection device according to the geometric structure information;

[0018] Dividing the surface of the lightning protection device into a plurality of current detection blocks through the surface division principle.

[0019] In some embodiments, calculating the induced field strength of each current detection block based on the equivalent uniform field response signal corresponding to the rotation moment, and then forming the field strength coupling relationship between the surface of the lightning protection device and the detection probe in the detection probe array specifically includes:

[0020] Obtaining position coordinates of each current detection block;

[0021] Calculating an induced field strength of a corresponding current detection block according to the equivalent uniform field response signal corresponding to the rotation moment and the position coordinates of each current detection block;

[0022] Obtaining a corresponding relationship between each current detection block and a detection probe in the detection probe array;

[0023] Forming a field strength coupling relationship between the surface of the lightning protection device and the detection probe in the detection probe array according to the corresponding relationship and all induced field strengths.

[0024] In some embodiments, the current density inversion of the surface of the lightning protection device is performed by combining the field strength coupling relationship with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment, and a density inversion field of the current of the surface of the lightning protection device at the rotation moment is obtained, which specifically includes:

[0025] Determining the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment;

[0026] Determining a field strength vector between the surface of the lightning protection device and the detection probe in the detection probe array according to the field strength coupling relationship and the frequency domain characteristics;

[0027] Reconstructing the current density of each current detection block through the field strength vector;

[0028] Determining the density inversion field of the current of the surface of the lightning protection device at the rotation moment according to all current densities.

[0029] In some embodiments, generating the current density topology map of the leakage current of the lightning protection device based on all density inversion fields specifically includes:

[0030] Superimposing and integrating all density inversion fields based on the position characteristics of each current detection block to obtain a current density superimposition map of the lightning protection device;

[0031] Determining the current density topology map of the leakage current of the lightning protection device according to the current density superimposition map.

[0032] In some embodiments, positioning the leakage current position of the lightning protection device by the current density abnormal area in the current density topology map specifically includes:

[0033] Obtaining a normal range and distribution rule of the current density of the surface of the lightning protection device;

[0034] Determining the current density abnormal area in the current density topology map according to the normal range and distribution rule of the current density;

[0035] determine the leakage current position of the lightning protection device through the current density abnormal area.

[0036] In some embodiments, a three-dimensional laser scanner is used to obtain the geometric structure information of the lightning protection device.

[0037] In some embodiments, the rotating electromagnetic field detection probe array is composed of high-sensitivity coil type magnetic sensors.

[0038] In a second aspect, the application provides a lightning protection device current leakage detection system, comprising:

[0039] The acquisition module is configured to acquire electromagnetic field response signals of the detection probe array under rotating excitation.

[0040] The processing module is configured to decompose the electromagnetic field response signals into equivalent uniform field response signals corresponding to different rotating instants of the rotating electromagnetic field, and divide the surface of the lightning protection device into a plurality of current detection blocks based on the geometric structure information of the lightning protection device.

[0041] The processing module is further configured to, for each rotating instant, calculate the induced field strength of each current detection block from the equivalent uniform field response signal corresponding to the rotating instant, thereby forming a field strength coupling relationship between the surface of the lightning protection device and the detection probes in the detection probe array, and performing current density inversion on the surface of the lightning protection device based on the field strength coupling relationship and the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotating instant, to obtain the density inversion field of the current on the surface of the lightning protection device at the rotating instant, and further obtain the density inversion field of the current on the surface of the lightning protection device at each rotating instant.

[0042] The execution module is configured to generate a current density topology map of the leakage current of the lightning protection device based on all the density inversion fields, and further locate the leakage current position of the lightning protection device from the current density abnormal area in the current density topology map.

[0043] The technical scheme provided by the embodiments of the application has the following beneficial effects:

[0044] The lightning protection device current leakage detection method and system provided by the application first collects the electromagnetic field response signal of the detection probe array under rotating excitation; the electromagnetic field response signal is decomposed into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotating moments, the surface of the lightning protection device is divided into multiple current detection blocks based on the geometric structure information of the lightning protection device; for each rotating moment, the induced field strength of each current detection block is calculated from the equivalent uniform field response signal corresponding to the rotating moment, thereby forming the field strength coupling relationship between the surface of the lightning protection device and the detection probe in the detection probe array, and the current density of the surface of the lightning protection device is inversely calculated through the field strength coupling relationship combined with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotating moment, thereby obtaining the density inversion field of the current on the surface of the lightning protection device at the rotating moment, and further obtaining the density inversion field of the current on the surface of the lightning protection device at each rotating moment; based on all the density inversion fields, the current density topology map of the lightning protection device leakage current is generated, and further the leakage current position of the lightning protection device is located from the current density abnormal area in the current density topology map.

[0045] It can be seen that, in the current leakage detection process, first, the electromagnetic field response signal under rotation excitation is collected: rotation excitation makes the electromagnetic field cover the device surface from multiple angles, overcoming signal shielding or attenuation caused by complex geometric structures (such as curved surfaces or uneven surfaces), and enhancing the comprehensiveness of data acquisition; second, the signal is decomposed into equivalent uniform field response signals at different rotation times: the decomposition process simplifies the non-uniform field into instantaneous uniform field, reduces the field strength distortion introduced by geometric complexity, and provides stable input for subsequent processing; third, the surface is divided into current detection blocks based on the geometric structure: the surface is discretized into dipole units, directly integrating the geometric details (such as shape and size) of the device, so that the model can adapt to complex structures and avoid geometric factors interfering with current distribution modeling; fourth, the induced field strength at each rotation time is calculated and the field strength coupling relationship is formed: the coupling relationship between the probe and the surface dipole is established for each time, accurately quantifying the influence of geometric structure on electromagnetic field, thereby isolating structural complexity in inversion and improving positioning reliability; fifth, the current density inversion is combined with frequency domain characteristics and the multi-time inversion field is integrated: frequency domain analysis filters out geometric noise, and multi-time inversion field combines rotation data, compensates for the blind area of single perspective, and ensures the spatial consistency of current density estimation under complex geometry; finally, the current density topology map is generated: the map integrates all inversion fields, intuitively presents the surface current distribution, and evenly distributes the geometric complexity, so that the abnormal area (such as the leakage point) is clearly highlighted in the high-resolution map, and the leakage current position is located: the abnormal area is identified through the topology map, and the leakage point is directly output, integrating multi-angle and frequency domain information, and minimizing the positioning deviation caused by geometric structure. By using the scheme, the influence of the complex geometric structure of the lightning protection device on the spatial positioning of the surface leakage current can be reduced BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is an example flow chart of a lightning protection device current leakage detection method according to some embodiments of the application;

[0047] Figure 2 is a deployment schematic diagram of a rotating electromagnetic field detection probe array according to some embodiments of the application;

[0048] Figure 3 is an example flow chart of determining a field strength coupling relationship according to some embodiments of the application;

[0049] Figure 4 is a structural schematic diagram of a lightning protection device current leakage detection system according to some embodiments of the application;

[0050] Figure 5 is a structural schematic diagram of a computer device for implementing a lightning protection device current leakage detection method according to some embodiments of the application. DETAILED DESCRIPTION

[0051] For better understanding of the technical solutions of the present application, the technical solutions of the present application will be described in detail below in combination with the drawings of the specification and specific embodiments.

[0052] Referring to Figure 1 The figure is an exemplary flow chart of a lightning protection device current leakage detection method according to some embodiments of the present application, which mainly includes the following steps:

[0053] In some embodiments, the deployment of a rotating electromagnetic field detection probe array near the lightning protection device can be implemented in the following manner, i.e. outside the periphery of the lightning protection device to be detected, a rotating electromagnetic field detection probe array composed of high-sensitivity coil-type magnetic sensors is fixed in multiple directions, for example, referring to Figure 2 The figure is a deployment schematic diagram of a rotating electromagnetic field detection probe array in some embodiments of the present application, the number of detection probes is set to 8-32 according to the detection accuracy requirement, uniformly distributed along the periphery of the device, with a spacing of 5-50 cm, fixed at a distance of 0.3-2 meters from the surface of the device through an insulating support, each detection probe is directed towards the surface of the device and the sensing direction is consistent, connected with the data acquisition equipment through a shielded cable wrapped in a metal shielding layer and grounded.

[0054] In some embodiments, the application of a controllable rotating electromagnetic field to the lightning protection device to be detected can be implemented in the following manner, i.e. deploying a multi-axis orthogonal coil system composed of 3 groups of orthogonal Helmholtz coils as an electromagnetic field generating device outside the periphery of the device to be detected, outputting a phase-difference-controllable alternating current signal through a signal generator, driving the three groups of coils through a power amplifier, adjusting the phase difference of the X and Y axis coil currents to 90°, synchronously controlling the Z axis coil current to adjust the rotating axis direction, making the synthesized electromagnetic field rotate around the center axis of the device at an angular velocity of 1-10 revolutions per second, and controlling the rotating direction by reversing the phase difference of the X / Y axis current, adjusting the rotating speed by changing the signal frequency, controlling the electromagnetic field strength (0.1-10 mT) by changing the current amplitude, and setting the electromagnetic field frequency range of 10 Hz-1 MHz to match the electromagnetic response characteristics of the device.

[0055] In step 101, the electromagnetic field response signal of the detection probe array under rotating excitation is collected.

[0056] In a specific implementation, each detection probe in the detection probe array converts the sensed change in the rotating electromagnetic field into a voltage signal according to the electromagnetic induction law, and the voltage signals are input into a multi-channel data acquisition card matched with the number of detection probes. The sampling frequency of the data acquisition card is 2-5 times the highest frequency of the electromagnetic field (for example, when the highest frequency of the electromagnetic field is 1 MHz, the sampling frequency is set to 2-5 MHz), and the sampling duration covers at least one complete rotation period (for example, when the rotation period is 1 second, the sampling duration is greater than or equal to 1 second). Meanwhile, the signal generator of the electromagnetic field generating device outputs a synchronization pulse to trigger the data acquisition card to start sampling, so that the time error between the collected signal and the rotation time of the electromagnetic field is less than or equal to 10 μs. The original signal is filtered by a band-pass filter matched with the frequency range of the electromagnetic field to remove power frequency interference and high-frequency noise, and is amplified by a gain of 10-100 times to improve the strength of the weak signal. Finally, the processed signal is taken as the electromagnetic field response signal of the detection probe array under the rotating excitation. In other embodiments, other ways of collection can also be used, which are not limited here.

[0057] It should be noted that the electromagnetic field response signal in the present application represents the electromagnetic change converted from the electromagnetic field formed by the induced current of the lightning protection device due to electromagnetic induction, which is captured by the detection probe array under the excitation of the rotating electromagnetic field. The electromagnetic field response signal carries the electromagnetic characteristic information of the lightning protection device generated under the excitation of the rotating electromagnetic field. Through processing and analysis of the signal, the surface current distribution and other related information of the device can be obtained, which provides a basis for detecting the position of the leakage current.

[0058] In step 102, the electromagnetic field response signal is decomposed into equivalent uniform field response signals corresponding to different rotation times of the rotating electromagnetic field, and the surface of the lightning protection device is divided into a plurality of current detection blocks based on the geometric structure information of the lightning protection device.

[0059] In some embodiments, the decomposition of the electromagnetic field response signal into equivalent uniform field response signals corresponding to different rotation times of the rotating electromagnetic field can be achieved by the following steps:

[0060] Obtaining different rotation times of the rotating electromagnetic field;

[0061] Selecting one rotation time as a selected rotation time, and extracting a piece of electromagnetic field response signal corresponding to the selected rotation time from the electromagnetic field response signal;

[0062] Determining the equivalent uniform field response signal corresponding to the selected rotation time of the rotating electromagnetic field according to the piece of electromagnetic field response signal;

[0063] Continuing to determine the equivalent uniform field response signals corresponding to the remaining rotation times of the rotating electromagnetic field.

[0064] The timer module based on the programmable gate array counts the rotating electromagnetic field pulse edge at a clock frequency of 100 MHz, generates a corresponding timestamp sequence according to a preset rotating angle interval (for example, 5°), each timestamp in the timestamp sequence represents a rotating time, and then different rotating times of the rotating electromagnetic field are obtained, and the timestamp precision can reach 10 ns, thereby ensuring the accuracy of the time reference of subsequent signal decomposition; the direct memory access technology is used to extract a signal segment between the selected rotating time and the adjacent time before and after from the electromagnetic field response signal, and the extracted signal segment is used as the electromagnetic field response signal segment corresponding to the selected rotating time, wherein the electromagnetic field response signal segment represents the signal segment corresponding to the selected rotating time in the electromagnetic field response signal.

[0065] In a specific implementation, the determination of the equivalent uniform field response signal corresponding to the selected rotating time of the rotating electromagnetic field according to the electromagnetic field response signal segment can be implemented in the following manner: the electromagnetic field response signal segment is first subjected to digital down-conversion processing to shift the signal frequency to the baseband; then, an adaptive filter based on the recursive least square algorithm is used to suppress noise of the electromagnetic field response signal segment, the filter order is set to 128, and the forgetting factor is set to 0.999 to quickly converge and track signal changes; then, the filtered signal is subjected to fast Fourier transform, the transform point number is 4096, a frequency component (the frequency window width is set to ±5 Hz) strictly aligned with the rotating electromagnetic field excitation frequency (for example, 5 kHz) is extracted in the frequency domain, and the frequency domain component is converted back to the time domain through inverse Fourier transform, thereby obtaining the equivalent uniform field response signal corresponding to the selected rotating time. In other embodiments, other manners can also be used for determination, which are not limited herein.

[0066] It should be noted that the equivalent uniform field response signal in the present application represents an electric signal when the rotating electromagnetic field is equivalent to a spatially uniformly distributed electromagnetic field (i.e., the field strength and direction remain consistent in the region where the device is located) at the selected rotating time, and the secondary electromagnetic field excited by the surface induced current of the lightning protection device is received by the detection probe array and converted into an electric signal

[0067] In some embodiments, the surface of the lightning protection device can be divided into a plurality of current detection blocks based on the geometric structure information of the lightning protection device in the following steps:

[0068] Obtaining the geometric structure information of the lightning protection device;

[0069] Determining the surface division principle of the lightning protection device according to the geometric structure information;

[0070] Dividing the surface of the lightning protection device into a plurality of current detection blocks according to the surface division principle.

[0071] The geometric structure information of the lightning protection device can be acquired in the following manner: a three-dimensional laser scanner is used to scan the surface of the lightning protection device in all directions, high-density point cloud data of the lightning protection device is acquired, the high-density point cloud data is imported into Geomagic software, point cloud denoising (statistical filtering algorithm is used to remove noise points outside 3 times the standard deviation of the average distance), splicing (multi-view point cloud alignment is realized based on the iterative closest point algorithm, and the coincidence degree is greater than or equal to 95%), and meshing processing are performed, and finally a three-dimensional triangular mesh model of the surface of the lightning protection device is generated, and each vertex coordinate, normal vector and triangular facet topological relationship in the three-dimensional triangular mesh model are taken as the geometric structure information of the lightning protection device, wherein the geometric structure information represents the information of the geometric structure of the surface of the lightning protection device.

[0072] In a specific implementation, the surface of the lightning protection device is divided into a plurality of current detection blocks according to the surface division principle determined based on the geometric structure information in the following manner: the surface division principle of the lightning protection device is determined based on the geometric feature analysis of the three-dimensional model and the geometric structure information, first, a curvature adaptation principle is used, a fine grid of 5mm*5mm is used for a region with a surface curvature greater than or equal to 0.1 rad / mm (such as a corner or a joint), a coarse grid of 10mm*10mm is used for a flat region with a surface curvature less than 0.1 rad / mm, and the current detection block can accurately reflect the local current change; second, a structure correlation principle is used, the grid size is reduced to 3mm*3mm at key positions where leakage is prone to occur at the interface of the insulating layer of the device and the connection point of the lead, and the division boundary coincides with the physical structure boundary; and third, an electromagnetic compatibility principle is used, the maximum size of the dipole is less than 1 / 20 of the wavelength of the detection signal (for example, when the excitation frequency is 10MHz, the wavelength is 30m, and the maximum size of the dipole is less than 1.5m, which is actually much smaller than the value), and electromagnetic coupling interference between dipoles is avoided; in other embodiments, the surface of the lightning protection device can be divided in other manners.

[0073] In a specific implementation, the surface of the lightning protection device is divided into a plurality of current detection blocks according to the surface division principle determined based on the geometric structure information in the following manner: a stereolithography file format model is loaded by using the matrix laboratory grid processing toolbox, a grid division algorithm based on region growing is called, and the surface of the lightning protection device is divided according to the surface division principle, first, the key area coordinates in the configuration file are used to preferentially subdivide the positions prone to leakage, and an initial fine grid is generated; then, the remaining regions are automatically classified according to the curvature threshold, and the corresponding size grid is generated by using the Delaunay triangulation algorithm; and each grid facet is regarded as a current detection block; in other embodiments, the surface of the lightning protection device can be divided in other manners.

[0074] It should be noted that the current detection block in this application represents a tiny current unit on the surface of the lightning protection device, which can be used to analyze the leakage current on the surface of the lightning protection device. The position coordinates of the current detection block are obtained by calculating the center of gravity of the surface, the surface normal vector is extracted as the current direction reference of the current detection block, and the surface area is calculated as the equivalent area of ​​the current detection block.

[0075] In step 103, for each rotation moment, the induced field strength of each current detection block is calculated based on the equivalent uniform field response signal corresponding to the rotation moment, thereby forming a field strength coupling relationship between the surface of the lightning protection device and the detection probes in the detection probe array. The current on the surface of the lightning protection device is density inverted through the field strength coupling relationship combined with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment, and the density inversion field of the current on the surface of the lightning protection device at the rotation moment is obtained, thereby obtaining the density inversion field of the current on the surface of the lightning protection device at each rotation moment.

[0076] In some embodiments, reference Figure 3 As shown in FIG. 1 , this figure is an exemplary flow chart for determining the field strength coupling relationship in some embodiments of the present application. In this embodiment, the induced field strength of each current detection block is calculated based on the equivalent uniform field response signal corresponding to the rotation moment, and the field strength coupling relationship between the surface of the lightning protection device and the detection probes in the detection probe array is formed. This can be achieved by using the following steps:

[0077] First, in step 1031, the position coordinates of each current detection block are obtained;

[0078] Next, in step 1032, the induced field strength of the corresponding current detection block is calculated based on the equivalent uniform field response signal corresponding to the rotation moment and the position coordinates of each current detection block;

[0079] Then, in step 1033, the corresponding relationship between each current detection block and the detection probe in the detection probe array is obtained;

[0080] Finally, in step 1034, a field strength coupling relationship between the surface of the lightning protection device and the detection probes in the detection probe array is formed according to the corresponding relationship and all the induced field strengths.

[0081] Wherein, first, the triangular facets corresponding to each current detection block are extracted from the three-dimensional triangular mesh model of the lightning protection device surface, and the three-dimensional coordinates of the three vertices of the triangular facets are obtained; the barycentric coordinates are calculated by the arithmetic mean of the three vertex coordinates according to the barycentric calculation formula, and the calculated barycentric coordinates are converted to the global coordinate system (if the facet is modeled based on the local coordinate system), and finally the converted coordinates are taken as the position coordinates of the corresponding current detection block, and the position coordinates of each current detection block are obtained; in other embodiments, other ways can also be used to obtain them, which are not limited here.

[0082] In a specific implementation, the induced field strength of the corresponding current detection block can be calculated according to the equivalent uniform field response signal corresponding to the rotation moment and the position coordinates of each current detection block in the following manner, that is, a calculation model is established based on the radio frequency module of the finite element electromagnetic simulation software using the frequency domain form of Maxwell's equations; the equivalent uniform field response signal corresponding to the rotation moment is input as the boundary condition of the model, and the calculation domain is set to be the spatial region containing all current detection blocks and detection probes based on the position coordinates of each current detection block; the induced electric field strength at the position of each current detection block is calculated through the calculation model, and each induced electric field strength is taken as the induced field strength of the corresponding current detection block, wherein the induced field strength represents the electric field strength generated by electromagnetic induction in the current detection block; in other embodiments, other ways can also be used for calculation, which are not limited here.

[0083] Wherein, the corresponding relationship between each current detection block and the detection probe in the detection probe array can be obtained in the following manner, that is, a three-dimensional spatial index structure (such as octree) is constructed, and the coordinate points of all current detection blocks and detection probes in the detection probe array are included in the index; for each detection probe, the set of current detection blocks around it is obtained through spatial neighborhood search (the search radius is set to 1.5 times the maximum size of the device), and the mapping relationship table of the detection probe and the dipole is established; at the same time, the distance from each dipole to each detection probe is calculated, and the dipole-detection probe pairs with a distance ≤10m are retained (the electromagnetic field attenuates significantly beyond this distance, and the influence on the detection result can be ignored), and finally a sparse corresponding relationship matrix is formed, which is taken as the corresponding relationship between each current detection block and the detection probe in the detection probe array, and the non-zero elements in the matrix represent the dipole-detection probe pairs with electromagnetic coupling, wherein the corresponding relationship represents the positional correspondence between each current detection block and the detection probe in the detection probe array; in other embodiments, other ways can also be used to obtain them, which are not limited here.

[0084] In a specific implementation, the field strength coupling relationship between the surface of the lightning protection device and the detection probes in the array of detection probes can be formed in the following manner according to the correspondence relationship and all the induced field strengths: an M×N zero matrix is created as an initial field strength coupling relationship H, where M is the number of detection probes and N is the number of current detection blocks; all valid dipole-detection probe pairs in the correspondence relationship are traversed, and the field strength transfer coefficient is calculated according to the distance and azimuth angle between the dipole-detection probe and the induced field strength calculated by using the reciprocity theorem in electromagnetic theory, where the field strength transfer coefficient represents a parameter value of the electromagnetic field transmission relationship between the current detection block and the detection probe, and quantitatively represents how the change of the field strength in the current detection block affects the field strength of the detection probe. The calculated transfer coefficient is filled in the corresponding position of the matrix, and a complete field strength coupling relationship H is finally formed. In other embodiments, other ways can also be used to form the field strength coupling relationship, which is not limited here.

[0085] It should be noted that the field strength coupling relationship in the present application represents the relationship between the electromagnetic field transmission between each current detection block and each detection probe, and can be used for reconstructive analysis of the current density on the surface of the lightning protection device.

[0086] In some embodiments, the current density on the surface of the lightning protection device is inversed by the field strength coupling relationship in combination with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment, and the density inversion field of the current on the surface of the lightning protection device at the rotation moment can be achieved in the following steps:

[0087] The frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment are determined.

[0088] The field strength vector between the surface of the lightning protection device and the detection probes in the array of detection probes is determined according to the field strength coupling relationship and the frequency domain characteristics.

[0089] The current density of each current detection block is reconstructed by the field strength vector.

[0090] The density inversion field of the current on the surface of the lightning protection device at the rotation moment is determined according to all the current densities.

[0091] It should be noted that based on the coupling law of electromagnetic field and current (the field strength association model of the current detection block and the detection probe constructed by the geometric structure of the lightning protection device), the frequency domain characteristics (such as the field strength amplitude and phase characteristics at different frequencies) contained in the uniform response signal of the rotating electromagnetic field at different moments are fused, and the spatial distribution of the current on the device surface (i.e. the density inversion field) is inversely solved by solving the electromagnetic inverse problem.

[0092] In a specific implementation, first, Fourier transform is performed on the equivalent uniform field response signal corresponding to the rotation time to obtain a frequency domain characteristic containing the amplitude and phase of each frequency component; second, the frequency domain characteristic (amplitude and phase of each frequency component) of the equivalent uniform field response signal corresponding to the rotation time is arranged according to the acquisition time to form an N×1 observation field strength vector, the observation field strength vector is weighted and corrected in combination with the detection probe sensitivity calibration coefficient (obtained by standard signal source calibration), a linear equation set (observation field strength vector = field strength coupling relationship × field strength vector) is solved by using the Tikhonov regularization method, and the regularization parameter is determined by the L curve method (a value corresponding to an inflection point of the curve is selected to balance the data fitting degree and the stability of the solution); and finally, a field strength vector between the lightning protection device surface and the detection probe in the detection probe array is obtained, wherein the field strength vector represents a physical vector of the electric field intensity and direction between the lightning protection device surface and the detection probe in the detection probe array; in other embodiments, other methods can also be used to determine the field strength vector, which is not limited here.

[0093] In a specific implementation, the current density of each current detection block can be reconstructed by the field strength vector and the frequency domain characteristic in the following manner, that is, the area of each current detection block corresponding to a triangular facet in a three-dimensional triangular mesh model is calculated by using the Heron formula, the current density of each current detection block is calculated, the size of the current density is the field strength vector divided by the area of the facet, and the direction is determined by the phase information of the field strength vector in combination with a facet normal vector (by converting the phase of the field strength vector into a spatial angle, matching the direction of the facet normal vector in a local coordinate system of the facet, ensuring that the direction is perpendicular to the surface of the facet and meets the right-hand screw rule), and thus the current density of each current detection block is obtained, wherein the current density represents the density of the current on the current detection block; in other embodiments, other methods can also be used to reconstruct the current density, which is not limited here.

[0094] It should be noted that the physical definition of the current detection block is related to the current density. The field strength vector (P) of the current detection block (current element) is defined as the product of the current intensity (I) and the facet vector (ΔS, the size is the area of the facet, and the direction is perpendicular to the facet), that is, P=I・ΔS (vector relationship, the amplitude satisfies |P|=I・ΔS); and the physical meaning of the current density (J) is the current intensity per unit area, that is, J=I / ΔS (size relationship). Combining the two formulas, it can be deduced that J=|P| / ΔS, which directly establishes the quantitative relationship between the amplitude of the field strength vector, the area of the facet, and the size of the current density. Therefore, when the current density is inverted by the field strength vector, the size of the current density can be obtained by dividing the amplitude of the field strength vector by the area of the corresponding facet, which not only meets the definition of the current density (unit area current), but also is consistent with the physical properties of the dipole model.

[0095] In a specific implementation, the density inversion field of the current of the lightning protection device surface at the rotating moment can be determined according to all the current densities in the following manner: the density inversion field of the current of the lightning protection device surface at the rotating moment is generated by combining all the current densities through a vector composition algorithm (such as a component superposition algorithm), the current density components in the x, y, and z directions are directly superposed according to the vector composition rule, the size of the resultant vector is calculated, the direction angle is determined by using a trigonometric function, and the resultant vector of each node is quickly obtained. In other embodiments, the density inversion field can also be determined by using a space-weighted composition algorithm or a coordinate system conversion composition algorithm, which is not limited here.

[0096] It should be noted that the density inversion field in the present application represents the physical field of the current density distribution state of the lightning protection device surface at the rotating moment, and can be used as a key physical field for evaluating the conductive performance of the device and optimizing the structural design.

[0097] In step 104, the current density topology map of the leakage current of the lightning protection device is generated based on all the density inversion fields, and then the leakage current position of the lightning protection device is located from the current density abnormal area in the current density topology map.

[0098] In some embodiments, the current density topology map of the leakage current of the lightning protection device can be generated based on all the density inversion fields in the following steps:

[0099] All the density inversion fields are superimposed and integrated based on the position characteristics of each current detection block to obtain the current density superposition map of the lightning protection device.

[0100] The current density topology map of the leakage current of the lightning protection device is determined according to the current density superposition map.

[0101] In a specific implementation, first, all density inversion fields are mapped to the surface of the lightning protection device based on the position characteristics (such as three-dimensional coordinates, spatial distance from adjacent dipoles, and normal vector angle of the surface element) of each current detection block: spatial gridding processing (the grid precision is set to 1 / 5 of the average size of the current detection block) is adopted, the current density vectors at the grid nodes are weighted and superimposed according to the distance from the current detection block to the node (the weight factor is 1 / d2, d is the straight-line distance from the dipole to the node), the direction information of the vector is retained during superimposition (the direction of the resultant vector is calculated by the vector composition rule), and a current density superimposition diagram containing the current density size (color mapping, 0~200A / m2 corresponds to blue to red) and direction (arrow direction) is generated, wherein the current density superimposition diagram represents the visualization diagram of the density inversion field of all current detection blocks, and abnormal areas with current density exceeding a threshold value (such as 50A / m2) are labeled, then, topological feature extraction is performed on the current density superimposition diagram: the Canny edge detection algorithm is used to identify the boundary of the abnormal area, the region growing method (the growing threshold is that the current density difference between adjacent nodes is less than 10A / m2) is used to merge the connected high current density areas, the skeleton extraction algorithm (based on morphological thinning operation) is used to extract the main path of the current in each connected area, and the topological structure is constructed according to the branch relationship of the path (the current density gradient at the branch point is greater than 30A / m2 / mm), and finally, the current density topological diagram of the leakage current of the lightning protection device is generated; in other embodiments, other methods can also be used to determine the same, which are not limited here.

[0102] It should be noted that the current density topological diagram in the present application reflects the graphical core structure characteristics of the leakage current density distribution of the lightning protection device, and can be used to analyze the conductive performance of the device, optimize the design of the protection structure, and provide a simple and core topological level reference, the current density topological diagram includes a main path (the line width is positively correlated with the current density size), a branch node (marked as a dot), and a high-risk area (filled with a red translucent block), and directly displays the distribution form, flow path, and key node of the leakage current on the surface of the device.

[0103] In some embodiments, the leakage current position of the lightning protection device is located by the current density abnormal area in the current density topological diagram, which can be achieved by the following steps:

[0104] Obtaining the normal range and distribution rule of the surface current density of the lightning protection device;

[0105] Determining the current density abnormal area in the current density topological diagram according to the normal range and distribution rule of the current density;

[0106] Determining the leakage current position of the lightning protection device through the current density abnormal area.

[0107] In a specific implementation, first, a current density benchmark model of the lightning protection device in a normal working state is established based on historical detection data of the lightning protection device and electromagnetic field simulation analysis, the model includes normal ranges (such as 0-30 A / m2 for the main structure and 30-50 A / m2 for key connection points) and distribution rules (such as uniform decrease along the conductor surface) of current densities of parts of the device, and is stored as a three-dimensional threshold matrix; then, the current density values in the current density topology graph are compared point by point with the normal ranges and distribution rules of the current density, an adaptive threshold algorithm (threshold is dynamically adjusted according to local area mean ± 3σ) is used to identify abnormal areas, and the topology structure characteristics (such as sudden interruption of the current path or high current density island) are combined for secondary confirmation, areas with current densities exceeding 120% of the upper limit or being lower than 30% of the lower limit are marked as current density abnormal areas in the current density topology graph, wherein the current density abnormal areas represent areas where the surface current density of the lightning protection device is abnormal; finally, the coordinates of the current density abnormal areas are converted to the entity model of the lightning protection device through a space mapping algorithm, the abnormal areas are highlighted on the virtual model of the device by combining three-dimensional visualization technology, and the three-dimensional coordinates of the leakage current position, the abnormality degree evaluation (such as mild leakage: 50-100 A / m2, severe leakage: > 100 A / m2) and the risk level (calculated by the product of the area of the abnormal area and the current density) are output, forming a leakage current diagnosis report containing accurate positioning information, and the whole process is automatically verified by a machine learning model (such as random forest).

[0108] In addition, another aspect of the present application, in some embodiments, the present application provides a lightning protection device current leakage detection system, referring to Figure 4 The figure is a structural schematic diagram of a lightning protection device current leakage detection system according to some embodiments of the present application, the lightning protection device current leakage detection system 400 includes a collection module 401, a processing module 402 and an execution module 403, which are described as follows:

[0109] The collection module 401 is mainly used for collecting the electromagnetic field response signal of the detection probe array under rotary excitation in the present application;

[0110] The processing module 402 is used for decomposing the electromagnetic field response signal into equivalent uniform field response signals corresponding to different rotation times of the rotating electromagnetic field, and dividing the surface of the lightning protection device into a plurality of current detection blocks based on the geometric structure information of the lightning protection device in the present application;

[0111] It should be noted that the processing module 402 is further configured to calculate, for each rotation time, the induced field strength of each current detection block by the equivalent uniform field response signal corresponding to the rotation time, and form a field strength coupling relationship between the surface of the lightning protection device and the detection probe in the detection probe array, and perform density inversion on the current of the surface of the lightning protection device by combining the field strength coupling relationship with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation time, to obtain the density inversion field of the current of the surface of the lightning protection device at the rotation time, and further obtain the density inversion field of the current of the surface of the lightning protection device at each rotation time.

[0112] The execution module 403 is mainly configured to generate the current density topological map of the leakage current of the lightning protection device based on all the density inversion fields, and further locate the leakage current position of the lightning protection device from the current density abnormal area in the current density topological map.

[0113] In addition, the present application further provides a computer device, which comprises a memory and a processor, the memory stores a code, and the processor is configured to acquire the code and execute the lightning protection device current leakage detection method described above.

[0114] In some embodiments, with reference to Figure 5 The figure is a structural schematic diagram of a computer device for implementing the lightning protection device current leakage detection method according to some embodiments of the present application. The lightning protection device current leakage detection method in the above embodiments can be implemented by the computer device shown in the figure, which is a computer device for implementing the lightning protection device current leakage detection method. Figure 5 The computer device 500 comprises at least one processor 501, a communication bus 502, a memory 503 and at least one communication interface 504.

[0115] The processor 501 can be a general central processing unit (CPU) or an application-specific integrated circuit (ASIC).

[0116] The communication bus 502 can be used to transmit information between the above components.

[0117] The memory 503 can be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM), or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, a magnetic disk storage or other magnetic storage devices, or any other medium capable of storing desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited to this. The memory 503 can exist independently, and is connected to the processor 501 through the communication bus 502. The memory 503 can also be integrated with the processor 501.

[0118] The memory 503 is configured to store program codes for implementing the solutions of the present application, and the processor 501 is configured to control the execution of the program codes. The processor 501 is configured to execute the program codes stored in the memory 503. The program codes can include one or more software modules. The methods used in the above embodiments can be implemented by the processor 501 and one or more software modules in the program codes in the memory 503.

[0119] The communication interface 504 is configured to communicate with other devices or communication networks, such as an Ethernet, a radio access network (RAN), a wireless local area network (WLAN), etc., using any transceiver-like device.

[0120] In specific implementations, as an example, the computer device can include multiple processors, each of which can be a single-CPU processor or a multi-CPU processor. The processor herein can refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0121] The computer device described above can be a general-purpose computer device or a special-purpose computer device. In a specific implementation, the computer device can be a desktop computer, a laptop computer, a network server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal device, a communication device, or an embedded device. The embodiments of the present application do not limit the type of the computer device.

[0122] In addition, the present application also provides a computer readable storage medium, which stores a computer program. The computer program is executed by a processor to implement the lightning protection device current leakage detection method described above.

[0123] Although the preferred embodiments of the present application have been described, those skilled in the art who are informed of the basic inventive concept can make additional changes and modifications to the embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0124] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method of lightning protection device current leakage detection, wherein, The method comprises the following steps: The electromagnetic field response signal of the detection probe array under the rotation excitation is collected; The electromagnetic field response signal is decomposed into the equivalent uniform field response signal corresponding to the rotation electromagnetic field at different rotation time, and the surface of the lightning protection device is divided into multiple current detection blocks based on the geometric structure information of the lightning protection device; For each rotation time, the induced field intensity of each current detection block is calculated from the equivalent uniform field response signal corresponding to the rotation time, and the field intensity coupling relationship between the surface of the lightning protection device and the detection probes in the detection probe array is formed, the current density inversion of the surface of the lightning protection device is carried out through the field intensity coupling relationship combined with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation time, and the density inversion field of the current of the surface of the lightning protection device at the rotation time is obtained, and then the density inversion field of the current of the surface of the lightning protection device at each rotation time is obtained; The current density topology of the leakage current of the lightning protection device is generated based on all the density inversion fields, and then the leakage current position of the lightning protection device is located from the current density abnormal area in the current density topology.

2. The method of claim 1, wherein, The electromagnetic field response signal is decomposed into the equivalent uniform field response signal corresponding to the rotation electromagnetic field at different rotation time, and the surface of the lightning protection device is divided into multiple current detection blocks based on the geometric structure information of the lightning protection device; The different rotation time of the rotation electromagnetic field is obtained; A rotation time is selected as the selected rotation time, and the electromagnetic field response signal segment corresponding to the selected rotation time is extracted from the electromagnetic field response signal; The equivalent uniform field response signal corresponding to the selected rotation time of the rotation electromagnetic field is determined according to the electromagnetic field response signal segment; The equivalent uniform field response signal corresponding to the remaining rotation time of the rotation electromagnetic field is continuously determined.

3. The method of claim 1, wherein, The surface of the lightning protection device is divided into multiple current detection blocks based on the geometric structure information of the lightning protection device, and the surface division principle of the lightning protection device is determined according to the geometric structure information; The position coordinates of each current detection block are obtained; The induced field intensity of the corresponding current detection block is calculated according to the equivalent uniform field response signal corresponding to the rotation time and the position coordinates of each current detection block; The corresponding relationship between each current detection block and the detection probes in the detection probe array is obtained; 4. The method of claim 1, wherein, The field intensity coupling relationship between the surface of the lightning protection device and the detection probes in the detection probe array is formed according to the corresponding relationship and all the induced field intensities. ​ ​ ​ ​ 5. The method of claim 1, wherein, The density inversion of the current on the lightning protection device surface is performed by combining the field strength coupling relationship with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation time, to obtain the density inversion field of the current on the lightning protection device surface at the rotation time, and the density inversion field of the current on the lightning protection device surface at the rotation time specifically includes: determining the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation time; determining the field strength vector between the lightning protection device surface and the detection probe in the detection probe array according to the field strength coupling relationship and the frequency domain characteristics; reconstructing the current density of each current detection block through the field strength vector; determining the density inversion field of the current on the lightning protection device surface at the rotation time according to all the current densities.

6. The method of claim 1, wherein, generating the current density topology map of the lightning protection device leakage current based on all the density inversion fields specifically includes: superimposing and integrating all the density inversion fields based on the position characteristics of each current detection block to obtain the current density superposition map of the lightning protection device; determining the current density topology map of the lightning protection device leakage current according to the current density superposition map.

7. The method of claim 1, wherein, positioning the leakage current position of the lightning protection device from the current density abnormal area in the current density topology map specifically includes: obtaining the normal range and distribution rule of the current density on the lightning protection device surface; determining the current density abnormal area in the current density topology map according to the normal range and distribution rule of the current density; determining the leakage current position of the lightning protection device through the current density abnormal area.

8. The method of claim 1, wherein, The geometric structure information of the lightning protection device is obtained by using a three-dimensional laser scanner.

9. The method of claim 1, wherein, The rotating electromagnetic field detection probe array is composed of high-sensitivity coil type magnetic sensors.

10. A lightning protection device current leakage detection system, wherein, The rotating electromagnetic field detection probe array is deployed near the lightning protection device, and a controllable rotating electromagnetic field is applied to the to-be-detected area of the lightning protection device during detection, and the system comprises: a collection module for collecting electromagnetic field response signals of the detection probe array under rotating excitation; a processing module for decomposing the electromagnetic field response signals into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation times, and dividing the surface of the lightning protection device into multiple current detection blocks based on the geometric structure information of the lightning protection device; the processing module is also used for calculating the induced field strength of each current detection block from the equivalent uniform field response signal corresponding to each rotation time, and then forming the field strength coupling relationship between the lightning protection device surface and the detection probe in the detection probe array, and performing density inversion on the current on the lightning protection device surface by combining the field strength coupling relationship with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation time, to obtain the density inversion field of the current on the lightning protection device surface at the rotation time, and then obtain the density inversion field of the current on the lightning protection device surface at each rotation time; The execution module is configured to generate a current density topological map of the lightning protection device leakage current based on all the density inversion fields, and then locate the lightning protection device leakage current position from an abnormal area of current density in the current density topological map.

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