Lightning protection device current leakage detection method and system

Abstract

The invention provides a lightning protection device current leakage detection method and system, and the method comprises the steps: firstly determining equivalent uniform field response signals corresponding to a rotating electromagnetic field at different rotating moments, and dividing the surface of a lightning protection device into a plurality of current detection blocks; the field intensity coupling relation between the surface of the lightning protection device and the detection probe in the detection probe array is determined according to the equivalent uniform field response signal corresponding to the rotation moment; determining a current density inversion field of the surface of the lightning protection device at the rotation moment by combining the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment through a field intensity coupling relationship; and generating a current density topological graph of the leakage current of the lightning protection device based on all the density inversion fields, and positioning the leakage current position of the lightning protection device according to a current density abnormal region in the current density topological graph. By adopting the scheme of the invention, the influence of the complex geometric structure of the lightning protection device on the space positioning of the surface leakage current can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of current leakage detection, and more specifically, to a method and system for detecting current leakage in a lightning protection device. Background Art

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

[0003] Lightning protection devices (such as lightning rods and down conductors) are exposed to harsh environments for a long time, and their insulation performance is easily degraded due to material aging, structural damage or loose connections, which can cause leakage current. Traditional detection methods (such as ground resistance measurement and infrared thermal imaging) have obvious limitations: it is difficult to locate tiny leakage points with high precision, and they are greatly affected by environmental interference; especially in devices with complex geometric structures, it is difficult to visualize the density distribution of leakage current, resulting in unclear hidden danger positioning and low maintenance efficiency. Although existing electromagnetic detection technology can sense current, it lacks the ability to respond to rotating dynamic excitation and analyzes the current density inversion model without combining the geometric characteristics of the device. As a result, the leakage point identification accuracy is insufficient and cannot meet the operation and maintenance requirements of high-reliability protection systems. Therefore, how to reduce the impact of the complex geometric structure of the lightning protection device on the spatial positioning of the surface leakage current has become a problem facing the industry. Summary of the Invention

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

[0005] In a first aspect, the present application provides a method for detecting current leakage in a lightning protection device, wherein a rotating electromagnetic field detection probe array is deployed near the lightning protection device, and a controllable rotating electromagnetic field is applied to a detection area of ​​the lightning protection device during detection. The method comprises the following steps: collecting electromagnetic field response signals of the detection probe array under rotational excitation; decomposing the electromagnetic field response signal into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments, and dividing the surface of the lightning protection device into a plurality of current detection blocks based on geometric structure information of the lightning protection device; 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 based on the field strength coupling relationship combined with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment to obtain a density inversion field of the current on the surface of the lightning protection device at the rotation moment, thereby obtaining a density inversion field of the current on the surface of the lightning protection device at each rotation moment; A current density topology map of the leakage current of the lightning protection device is generated based on all density inversion fields, and then the leakage current position of the lightning protection device is located according to the current density abnormal area in the current density topology map.

[0006] In some embodiments, decomposing the electromagnetic field response signal into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments specifically includes: obtaining different rotation moments of the rotating electromagnetic field; selecting a 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; determining an equivalent uniform field response signal corresponding to the rotating electromagnetic field at a selected rotation moment based on the electromagnetic field response signal segment; Continue to determine the equivalent uniform field response signal corresponding to the rotating electromagnetic field at the remaining rotation moments.

[0007] 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: Acquiring geometric structure information of the lightning protection device; determining a surface division principle of the lightning protection device according to the geometric structure information; The surface of the lightning protection device is divided into a plurality of current detection blocks according to the surface division principle.

[0008] 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 a field strength coupling relationship between the surface of the lightning protection device and the detection probes in the detection probe array specifically includes: Obtain the position coordinates of each current detection block; Calculating the induced field strength of the 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; Acquiring a correspondence between each current detection block and the detection probes in the detection probe array; A field strength coupling relationship is formed between the surface of the lightning protection device and the detection probes in the detection probe array according to the corresponding relationship and all the induced field strengths.

[0009] In some embodiments, performing density inversion on the current on 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 moment to obtain the density inversion field of the current on the surface of the lightning protection device at the rotation moment specifically includes: Determining the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment; Determining a field intensity vector between the surface of the lightning protection device and a detection probe in the detection probe array according to the field intensity coupling relationship and the frequency domain characteristics; reconstructing the current density of each current detection block through the field intensity vector; A density inversion field of the current on the surface of the lightning protection device at the rotation moment is determined according to all current densities.

[0010] In some embodiments, generating a current density topology map of the leakage current of the lightning protection device based on all density inversion fields specifically includes: Based on the position characteristics of each current detection block, all density inversion fields are superimposed and integrated to obtain a current density superposition map of the lightning protection device; A current density topology diagram of the leakage current of the lightning protection device is determined according to the current density superposition diagram.

[0011] In some embodiments, locating the leakage current position of the lightning protection device based on the current density abnormal area in the current density topology map specifically includes: Obtaining the normal range and distribution pattern of surface current density of the lightning protection device; Determining a current density abnormal area in the current density topology map according to a normal range and distribution pattern of the current density; The leakage current position of the lightning protection device is determined through the abnormal current density area.

[0012] In some embodiments, a three-dimensional laser scanner is used to obtain geometric structure information of the lightning protection device.

[0013] In some embodiments, the rotating electromagnetic field detection probe array is composed of high-sensitivity coil-type magnetic sensors.

[0014] In a second aspect, the present application provides a lightning protection device current leakage detection system, comprising: An acquisition module, configured to acquire an electromagnetic field response signal of the detection probe array under rotational excitation; a processing module, configured to decompose the electromagnetic field response signal into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments, and divide the surface of the lightning protection device into a plurality of current detection blocks based on geometric structure information of the lightning protection device; The processing module is further configured to calculate, for each rotation moment, the induced field strength of each current detection block 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; perform density inversion on the current on the surface of the lightning protection device based on the field strength coupling relationship in combination with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment, thereby obtaining a density inversion field of the current on the surface of the lightning protection device at the rotation moment, and further obtaining a density inversion field of the current on the surface of the lightning protection device at each rotation moment; An execution module is used to generate a current density topology map of the leakage current of the lightning protection device based on all density inversion fields, and then locate the leakage current position of the lightning protection device according to the current density abnormal area in the current density topology map.

[0015] The technical solutions provided by the embodiments disclosed in this application have the following beneficial effects: In the lightning protection device current leakage detection method and system provided in the present application, the electromagnetic field response signal of the detection probe array under rotational excitation is first collected; the electromagnetic field response signal is decomposed into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments, 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 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 based on the field strength coupling relationship combined with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment, to obtain a density inversion field of the current on the surface of the lightning protection device at the rotation moment, and further obtain the density inversion field of the current on the surface of the lightning protection device at each rotation moment; based on all the density inversion fields, a current density topology 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 based on the current density abnormality area in the current density topology map.

[0016] It can be seen that in the current leakage detection process, the present application first collects the electromagnetic field response signal under rotational excitation: the rotational excitation makes the electromagnetic field cover the surface of the device from multiple angles, overcomes the signal shielding or attenuation caused by complex geometric structures (such as curved or uneven surfaces), and enhances the comprehensiveness of data acquisition; secondly, the signal is decomposed into equivalent uniform field response signals at different rotation moments: the decomposition process simplifies the non-uniform field into an instantaneous uniform field, reduces the field strength distortion introduced by geometric complexity, and provides a stable input for subsequent processing; then, the surface is divided into current detection blocks based on the geometric structure: by discretizing the surface into dipole units, the geometric details of the device (such as shape and size) are directly integrated, so that the model can adapt to complex structures and avoid geometric factors interfering with current distribution modeling; then, the induced field strength at each rotation moment is calculated and the field strength is formed. Coupling relationship: Establish the coupling relationship between the probe and the surface dipole for each moment, accurately quantify the influence of the geometric structure on the electromagnetic field, thereby isolating the structural complexity in the inversion and improving the positioning reliability; then, combine the frequency domain characteristics to perform current density inversion and integrate the multi-moment inversion field: the frequency domain analysis filters out the geometric noise, and the multi-moment inversion field integrates the rotation data, compensates for the blind spot of a single perspective, and ensures the spatial consistency of the current density estimation under complex geometry; finally, generate a current density topology map: this map integrates all inversion fields and intuitively presents the surface current distribution. The geometric complexity is evenly distributed, so that abnormal areas (such as leakage points) are 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. It integrates multi-angle and frequency domain information to minimize the positioning deviation caused by the geometric structure. The use of this application solution can reduce the influence of the complex geometric structure of the lightning protection device on the spatial positioning of the surface leakage current. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is an exemplary flow chart of a current leakage detection method for a lightning protection device according to some embodiments of the present application; Figure 2 is a schematic diagram of the deployment of a rotating electromagnetic field detection probe array according to some embodiments of the present application; Figure 3 is an exemplary flow chart of determining a field strength coupling relationship according to some embodiments of the present application; Figure 4 is a structural diagram of a current leakage detection system for a lightning protection device according to some embodiments of the present application; Figure 5 It is a structural diagram of a computer device for implementing a current leakage detection method for a lightning protection device according to some embodiments of the present application. DETAILED DESCRIPTION

[0018] In order to better understand the technical solution of the present application, the technical solution of the present application will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0019] refer to Figure 1 , which is an exemplary flow chart of a lightning protection device current leakage detection method according to some embodiments of the present application. The lightning protection device current leakage detection method mainly includes the following steps: In some embodiments, the deployment of a rotating electromagnetic field detection probe array near the lightning protection device can be achieved in the following manner, that is, a rotating electromagnetic field detection probe array composed of high-sensitivity coil-type magnetic sensors is fixed in a multi-directional distribution outside the area to be detected by the lightning protection device, for example, Figure 2 As shown in the figure, this figure is a deployment diagram of the 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 requirements, evenly distributed along the periphery of the device, with a spacing of 5-50 cm, and fixed at 0.3-2 meters from the surface of the device by an insulating bracket. Each detection probe faces the surface of the device and has the same sensing direction. It is connected to the data acquisition device through a shielded cable wrapped with a metal shielding layer and grounded.

[0020] In some embodiments, applying a controllable rotating electromagnetic field to the area to be detected of the lightning protection device during detection can be achieved in the following manner: a multi-axis orthogonal coil system consisting of three groups of orthogonal Helmholtz coils is deployed as an electromagnetic field generating device outside the area to be detected of the device, an alternating current signal with controllable phase difference is output by a signal generator, the three groups of coils are driven by a power amplifier, the phase difference of the X- and Y-axis coil currents is adjusted to 90°, the Z-axis coil current is synchronously controlled to adjust the direction of the rotation axis, so that the synthesized electromagnetic field rotates around the central axis of the device at an angular velocity of 1-10 revolutions per second, and the rotation direction is controlled by reversing the X / Y-axis current phase difference, the rotation speed is adjusted by changing the signal frequency, the electromagnetic field intensity (0.1-10 mT) is controlled by changing the current amplitude, and the electromagnetic field frequency range of 10 Hz-1 MHz is set to match the electromagnetic response characteristics of the device.

[0021] In step 101, electromagnetic field response signals of the detection probe array under rotational excitation are collected.

[0022] In specific implementation, each detection probe in the detection probe array converts the sensed changes in the rotating electromagnetic field into a voltage signal according to the law of electromagnetic induction. These voltage signals are connected to a multi-channel data acquisition card that matches the number of detection probes. The sampling frequency set by the acquisition card is 2-5 times the highest frequency of the electromagnetic field (for example, when the highest frequency of the electromagnetic field is 1MHz, the sampling frequency is set to 2-5MHz), and the sampling time covers at least one complete rotation cycle (for example, when the rotation cycle is 1 second, the sampling time is ≥1 second); at the same time, the signal generator of the electromagnetic field generating device outputs a synchronous pulse to trigger the data acquisition card to start sampling, ensuring that the time error between the collected signal and the moment of electromagnetic field rotation is ≤10μs. The collected original signal is filtered by a bandpass filter that matches the electromagnetic field frequency range to remove power frequency interference and high-frequency noise, and the weak signal strength is enhanced by amplification with a gain of 10-100 times. Finally, the processed signal is used as the electromagnetic field response signal of the detection probe array under rotational excitation; in other embodiments, other methods can also be used for collection, which are not limited here.

[0023] It should be noted that the electromagnetic field response signal in this application indicates that under the excitation of the rotating electromagnetic field, the lightning protection device generates an induced current due to electromagnetic induction, and the electromagnetic field formed is captured by the detection probe array, which is converted into an electrical signal by the electromagnetic changes. It carries the electromagnetic characteristic information generated by the lightning protection device under the excitation of the rotating electromagnetic field. By processing and analyzing this signal, relevant information such as the current distribution on the surface of the device can be obtained, providing a basis for detecting the location of the leakage current.

[0024] In step 102, the electromagnetic field response signal is decomposed into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments, and the surface of the lightning protection device is divided into multiple current detection blocks based on geometric structure information of the lightning protection device.

[0025] In some embodiments, decomposing the electromagnetic field response signal into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments can be achieved by using the following steps: obtaining different rotation moments of the rotating electromagnetic field; selecting a 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; determining an equivalent uniform field response signal corresponding to the rotating electromagnetic field at a selected rotation moment based on the electromagnetic field response signal segment; Continue to determine the equivalent uniform field response signal corresponding to the rotating electromagnetic field at the remaining rotation moments.

[0026] Among them, the timer module based on the programmable gate array counts the edges of the rotating electromagnetic field pulse at a clock frequency of 100MHz, and generates a corresponding timestamp sequence according to a preset rotation angle interval (such as 5°). Each timestamp in the timestamp sequence represents a rotation moment, thereby obtaining different rotation moments of the rotating electromagnetic field. The timestamp accuracy can reach 10ns, ensuring the accuracy of the time base for subsequent signal decomposition; direct memory access technology is used to extract the signal segment between the selected rotation moment and the adjacent moments 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 rotation moment, wherein the electromagnetic field response signal segment represents the signal segment corresponding to the selected rotation moment in the electromagnetic field response signal.

[0027] In a specific implementation, determining the equivalent uniform field response signal corresponding to the rotating electromagnetic field at the selected rotation moment based on the electromagnetic field response signal segment can be achieved in the following manner, namely: first digitally down-converting the electromagnetic field response signal segment to move the signal frequency to the baseband; then adopting an adaptive filter based on a recursive least squares algorithm to suppress noise on the electromagnetic field response signal segment, with the filter order set to 128 and the forgetting factor set to 0.999 to quickly converge and track signal changes; then performing a fast Fourier transform on the filtered signal with 4096 transformation points, extracting a frequency component that is strictly aligned with the rotating electromagnetic field excitation frequency (such as 5kHz) in the frequency domain (the frequency window width is set to ±5Hz), and converting the frequency domain component back to the time domain through an inverse Fourier transform, thereby obtaining the equivalent uniform field response signal corresponding to the selected rotation moment; in other embodiments, other methods can also be used for determination, which are not limited here.

[0028] It should be noted that the equivalent uniform field response signal in this application represents the electrical signal when the rotating electromagnetic field is equivalent to an electromagnetic field with uniform spatial distribution (i.e., the field strength and direction remain consistent within the area where the device is located) at the selected rotation moment, and the electrical signal after the secondary electromagnetic field excited by the induced current on the surface of the lightning protection device is received and converted by the detection probe array. 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 can be achieved by using the following steps: Acquiring geometric structure information of the lightning protection device; determining a surface division principle of the lightning protection device according to the geometric structure information; The surface of the lightning protection device is divided into a plurality of current detection blocks according to the surface division principle.

[0029] Among them, obtaining the geometric structure information of the lightning protection device can be achieved in the following manner, namely: using a three-dimensional laser scanner to perform a full-scale scan of the surface of the lightning protection device to obtain high-density point cloud data of the lightning protection device, importing the high-density point cloud data into the Geomagic software, and performing point cloud denoising (using a statistical filtering algorithm to remove noise points beyond 3 times the standard deviation of the average distance), splicing (based on an iterative nearest point algorithm to achieve multi-perspective point cloud alignment, with an overlap degree ≥95%), and meshing processing to finally generate a three-dimensional triangular mesh model of the surface of the lightning protection device, and using the coordinates of each vertex, normal vector, and topological relationship of the triangle facets in the three-dimensional triangular mesh model as the geometric structure information of the lightning protection device, wherein the geometric structure information represents information on the geometric structure of the surface of the lightning protection device; in other embodiments, other methods can also be used to obtain it, which is not limited here.

[0030] In a specific implementation, the surface division principle of the lightning protection device can be 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 in combination with the geometric structure information. First, the curvature adaptation principle is adopted. A fine grid of 5 mm × 5 mm is used for areas with a surface curvature ≥ 0.1 rad / mm (such as corners and seams), and a coarse grid of 10 mm × 10 mm is used for flat areas with a curvature < 0.1 rad / mm, to ensure that the current detection block can accurately reflect local current changes. Second, the structural association principle is adopted. At the device's insulation layer interface and lead connection points, which are key areas prone to leakage, the grid size is reduced to 3 mm × 3 mm, and the division boundary coincides with the physical structure boundary. Third, the electromagnetic compatibility principle is adopted. The maximum size of the dipole does not exceed 1 / 20 of the detection signal wavelength (e.g., when the excitation frequency is 10 MHz and the wavelength is 30 m, the maximum size of the dipole is ≤ 1.5 m, which is actually much smaller than this value). This avoids electromagnetic coupling interference between dipoles. In other embodiments, other determination methods can also be adopted, which are not limited here.

[0031] In specific implementation, the surface of the lightning protection device is divided into multiple current detection blocks according to the surface division principle, which can be achieved in the following manner, namely: using the grid processing toolbox of the matrix laboratory to load the stereolithography file format model, calling the region growth-based grid division algorithm combined with the surface division principle to divide the surface of the lightning protection device, first according to the key area coordinates in the configuration file, give priority to subdividing the leakage-prone parts to generate an initial fine grid; then automatically classify the remaining areas according to the curvature threshold, and generate a grid of corresponding size through the Delaunay triangulation algorithm; regard each grid facet as a current detection block; in other embodiments, other division methods can also be used, which are not limited here.

[0032] 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.

[0033] 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.

[0034] 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: First, in step 1031, the position coordinates of each current detection block are obtained; 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; Then, in step 1033, the corresponding relationship between each current detection block and the detection probe in the detection probe array is obtained; 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.

[0035] Among them, the triangular facets corresponding to each current detection block are first extracted from the three-dimensional triangular mesh model of the surface of the lightning protection device, and the three-dimensional coordinates of the three vertices of the triangular facet are obtained; the arithmetic mean of the coordinates of the three vertices is calculated according to the center of gravity calculation formula to obtain the center of gravity coordinates, and the calculated center of gravity 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 used as the position coordinates of the corresponding current detection block, thereby obtaining the position coordinates of each current detection block; in other embodiments, other methods can also be used to obtain, which are not limited here.

[0036] In specific implementation, 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, which can be achieved in the following manner, namely: a calculation model is established based on the frequency domain form of Maxwell's equations using the radio frequency module of the finite element electromagnetic simulation software; the equivalent uniform field response signal corresponding to the rotation moment is input into the model as a boundary condition, and the calculation domain is set to a spatial region including 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 by this calculation model, and each induced electric field strength is used as the induced field strength of the corresponding current detection block, wherein the induced field strength represents the electric field strength generated by the electromagnetic induction phenomenon in the current detection block; in other embodiments, other calculation methods can also be used, which are not limited here.

[0037] Obtaining the correspondence between each current detection block and the detection probes in the detection probe array can be achieved in the following manner: constructing a three-dimensional spatial index structure (such as an octree) and incorporating the coordinate points of all current detection blocks and detection probes in the detection probe array into the index; for each detection probe, obtaining the set of current detection blocks surrounding it through a spatial neighborhood search (the search radius is set to 1.5 times the maximum size of the device), and establishing a mapping relationship table between the detection probes and dipoles; simultaneously calculating the distance from each dipole to each detection probe, retaining dipole-detection probe pairs with a distance ≤ 10m (the electromagnetic field attenuation is significant beyond this distance, and the impact on the detection results is negligible), and finally forming a sparse correspondence matrix, which is used as the correspondence between each current detection block and the detection probes in the detection probe array. Non-zero elements in the matrix indicate the presence of electromagnetically coupled dipole-detection probe pairs, wherein the correspondence represents the positional correspondence between each current detection block and the detection probes in the detection probe array. In other embodiments, other methods can also be used for acquisition, which are not limited here.

[0038] In specific implementation, the 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. This can be achieved in the following manner: creating an M×N zero matrix 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; traversing all valid dipole-detection probe pairs in the corresponding relationship, and calculating the field strength transfer coefficient according to the reciprocity theorem in electromagnetic theory using the calculated induced field strength and the distance and azimuth between the dipole-detection probe. The field strength transfer coefficient represents the parameter value of the electromagnetic field transfer relationship between the current detection block and the detection probe, and quantitatively characterizes how the change in 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 to finally form a complete field strength coupling relationship H. In other embodiments, other methods can also be used, which are not limited here.

[0039] It should be noted that the field strength coupling relationship in this application represents the relationship between the electromagnetic field transmission conditions between each current detection block and each detection probe, and can be used to reconstruct and analyze the current density on the surface of the lightning protection device.

[0040] In some embodiments, density inversion of the current on 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. Obtaining the density inversion field of the current on the surface of the lightning protection device at the rotation moment can be achieved by the following steps: Determining the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment; Determining a field intensity vector between the surface of the lightning protection device and a detection probe in the detection probe array according to the field intensity coupling relationship and the frequency domain characteristics; reconstructing the current density of each current detection block through the field intensity vector; A density inversion field of the current on the surface of the lightning protection device at the rotation moment is determined according to all current densities.

[0041] It should be noted that based on the coupling law of electromagnetic field and current (the field strength correlation model of the current detection block and the detection probe constructed by the geometric structure of the lightning protection device), the frequency domain characteristics contained in the uniform response signal of the rotating electromagnetic field at different times (such as the field strength amplitude and phase characteristics at different frequencies) are integrated, and the spatial distribution of current on the surface of the device (i.e., the density inversion field) is inferred by solving the electromagnetic inverse problem.

[0042] In a specific implementation, first, a Fourier transform is performed on the equivalent uniform field response signal corresponding to the rotation moment to obtain its frequency domain characteristics including the amplitude and phase of each frequency component. Second, the frequency domain characteristics (amplitude and phase of each frequency component) of the equivalent uniform field response signal corresponding to the rotation moment are 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 through standard signal source calibration). The Tikhonov regularization method is used to solve the linear equation system (observation field strength vector = field strength coupling relationship × field strength vector). The regularization parameter is determined by the L-curve method (selecting the value corresponding to the inflection point of the curve to balance the data fit and the stability of the solution). Finally, the field strength vector between the surface of the lightning protection device and the detection probes in the detection probe array is obtained, wherein the field strength vector represents the physical vector of the magnitude and direction of the electric field strength between the surface of the lightning protection device and the detection probes in the detection probe array. In other embodiments, other methods can also be used for determination, which are not limited here.

[0043] In specific implementation, the current density of each current detection block can be reconstructed by the field intensity vector and the frequency domain characteristics in the following manner, namely: the vertex coordinates of the triangular facets in the three-dimensional triangular mesh model are used to calculate the surface area corresponding to each current detection block by using the Heron formula, and the current density is calculated for each current detection block. The magnitude of the current density is the field intensity vector divided by the surface area, and the direction is determined by the phase information of the field intensity vector combined with the surface element normal vector (by converting the phase of the field intensity vector into a spatial angle, matching the normal vector direction of the surface element local coordinate system, ensuring that the direction is perpendicular to the surface element surface and complies with the right-hand screw rule), thereby obtaining the current density of each current detection block, wherein the current density represents the density of the current on the current detection block; in other embodiments, other methods can also be used for reconstruction, which are not limited here.

[0044] It should be noted that the physical definition of the current sensing block is intrinsically linked to the current density: the field strength vector (P) of the current sensing block (current element) is defined as "the product of the current intensity (I) and the surface element vector (ΔS, whose magnitude is the surface element area and whose direction is perpendicular to the surface element)", that is, P = I・ΔS (vector relationship, whose amplitude satisfies |P| = I・ΔS); while the physical meaning of current density (J) is "the current intensity per unit area", that is, J = I / ΔS (magnitude relationship). Combining the two equations, we can deduce that: J = |P| / ΔS. This derivation directly establishes a quantitative relationship between the amplitude of the field strength vector, the surface element area, and the magnitude of the current density. Therefore, when inverting the current density through the field strength vector, the magnitude of the current density can be obtained by dividing the amplitude of the field strength vector by the corresponding surface element area. This conforms to the definition of current density (current per unit area) and is also self-consistent with the physical properties of the dipole model.

[0045] In specific implementation, the density inversion field of the current on the surface of the lightning protection device at the rotation moment is determined based on all current densities in the following manner, namely: a vector synthesis algorithm (such as a component superposition algorithm) is used to combine all current densities to generate a density inversion field of the current on the surface of the lightning protection device at the rotation moment, the current density components in the x, y, and z directions are directly superimposed according to the vector synthesis rule, the size of the resultant vector is calculated, the direction angle is determined using trigonometric functions, and the resultant vector of each node is quickly obtained. In other embodiments, a spatial weighted synthesis algorithm or a coordinate system conversion synthesis algorithm can also be used for determination, which is not limited here.

[0046] It should be noted that the density inversion field in this application represents the physical field of the current density distribution state on the surface of the lightning protection device in space at the moment of rotation, which can be used to evaluate the conductive performance of the device and optimize the key physical quantity field of the structural design.

[0047] In step 104, a current density topology map of the leakage current of the lightning protection device is generated based on all density inversion fields, and then the leakage current position of the lightning protection device is located according to the current density abnormal area in the current density topology map.

[0048] In some embodiments, generating a current density topology map of the leakage current of the lightning protection device based on all density inversion fields can be achieved by using the following steps: Based on the position characteristics of each current detection block, all density inversion fields are superimposed and integrated to obtain a current density superposition map of the lightning protection device; A current density topology diagram of the leakage current of the lightning protection device is determined according to the current density superposition diagram.

[0049] In the specific implementation, first, all density inversion fields are mapped to the three-dimensional grid model surface of the lightning protection device based on the position characteristics of each current detection block (such as three-dimensional coordinates, spatial distance to adjacent dipoles, and angle between the surface element normal vectors): spatial gridding is used (the grid accuracy is set to 1 / 5 of the average size of the current detection block), and 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 between the dipole and the node), retains the direction information of the vector during superposition (the direction of the resultant vector is calculated using the vector composition rule), and generates a current density overlay map containing the current density magnitude (color mapping, 0-200 A / m² corresponds to blue to red) and direction (arrow direction). The current density overlay map represents a visualization of the density inversion field of all current detection blocks, and anomaly areas where the current density exceeds a threshold (e.g., 50 A / m²) are marked. Subsequently, topological feature extraction is performed on the current density overlay map: the boundaries of the anomaly areas are identified using the Canny edge detection algorithm, and connected high current density areas are merged using the region growing method (the growth threshold is the current density difference between adjacent nodes <10 A / m²). The skeleton extraction algorithm (based on morphological thinning operations) is used to extract the main current path within each connected area. Then, a topological structure is constructed based on the branching relationship of the path (the current density gradient at the branch point is >30 A / m² / mm), and finally a current density topological map of the leakage current of the lightning protection device is generated. In other embodiments, other methods can also be used for determination, which are not limited here.

[0050] It should be noted that the current density topology map in this application reflects the core structural characteristics of the leakage current density distribution of the lightning protection device, which can be used to analyze the conductive performance of the device and optimize the protection structure design to provide a concise and core topological level reference. The current density topology map includes the main path (line width is positively correlated with the current density), branch nodes (marked as dots) and high-risk areas (filled with red translucent blocks), which intuitively display the distribution pattern, flow path and key nodes of the leakage current on the surface of the device.

[0051] In some embodiments, locating the leakage current position of the lightning protection device based on the current density abnormal area in the current density topology map can be achieved by using the following steps: Obtaining the normal range and distribution pattern of surface current density of the lightning protection device; Determining a current density abnormal area in the current density topology map according to a normal range and distribution pattern of the current density; The leakage current position of the lightning protection device is determined through the abnormal current density area.

[0052] In specific implementation, first, a current density benchmark model of the lightning protection device under normal working conditions is established based on the historical detection data of the lightning protection device and electromagnetic field simulation analysis. The model includes the normal range of current density in various parts of the device (such as 0-30A / m² for the main structure, 30-50A / m² for key connection points) and distribution rules (such as uniform decrease along the conductor surface), and is stored as a three-dimensional threshold matrix; then, the current density values ​​in the current density topology map are compared point by point with the normal range and distribution rules of current density, and an adaptive threshold algorithm is used (the threshold is dynamically adjusted according to the local area mean ±3σ) to identify abnormal areas. At the same time, a secondary confirmation is performed in combination with the topological structure characteristics (such as sudden interruption of the current path or high current density islands), marking the current density exceeding the normal upper limit. For areas where the current density is 120% or 30% lower than the lower limit, the area is regarded as the current density abnormal area in the current density topology map, wherein the current density abnormal area indicates the area where the current density on the surface of the lightning protection device is abnormal; finally, the coordinates of the current density abnormal area are converted to the physical model of the lightning protection device through the spatial mapping algorithm, and the abnormal area is highlighted on the virtual model of the device with the help of three-dimensional visualization technology, and the three-dimensional coordinates of the leakage current position, the abnormality assessment (such as mild leakage: 50-100A / m², severe leakage: >100A / m²) and the risk level (calculated by multiplying the area of ​​the abnormal area by the current density) are output to form a leakage current diagnosis report containing precise positioning information. The entire process is automatically verified by a machine learning model (such as random forest).

[0053] In addition, in 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 , which is a schematic structural 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: an acquisition module 401, a processing module 402, and an execution module 403, which are described as follows: Acquisition module 401, in this application, acquisition module 401 is mainly used to acquire the electromagnetic field response signal of the detection probe array under rotation excitation; Processing module 402, in the present application, is configured to decompose the electromagnetic field response signal into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments, and divide the surface of the lightning protection device into a plurality of current detection blocks based on geometric structure information of the lightning protection device; It should be noted that the processing module 402 in the present application is also used to calculate the induced field strength of each current detection block from the equivalent uniform field response signal corresponding to the rotation moment for each 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, and perform density inversion on the current on the surface of the lightning protection device through the field strength coupling relationship combined with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment to obtain the density inversion field of the current on the surface of the lightning protection device at the rotation moment, and then obtain the density inversion field of the current on the surface of the lightning protection device at each rotation moment; Execution module 403, in this application, execution module 403 is mainly used to generate a current density topology map of the leakage current of the lightning protection device based on all density inversion fields, and then locate the leakage current position of the lightning protection device from the current density abnormal area in the current density topology map.

[0054] In addition, the present application also provides a computer device, which includes a memory and a processor, wherein the memory stores code, and the processor is configured to obtain the code and execute the above-mentioned lightning protection device current leakage detection method.

[0055] In some embodiments, reference Figure 5 , which is a schematic diagram of the structure of a computer device for implementing a current leakage detection method for a lightning protection device according to some embodiments of the present application. The current leakage detection method for a lightning protection device in the above embodiment can be performed by Figure 5 The computer device 500 shown in FIG. 5 is implemented as shown in FIG. 5 . The computer device 500 includes at least one processor 501 , a communication bus 502 , a memory 503 , and at least one communication interface 504 .

[0056] The processor 501 may be a general-purpose central processing unit (CPU) or an application-specific integrated circuit (ASIC).

[0057] The communication bus 502 may be used to transmit information between the aforementioned components.

[0058] The memory 503 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, a random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), a magnetic disk or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto. The memory 503 may be independent and connected to the processor 501 via the communication bus 502. The memory 503 may also be integrated with the processor 501.

[0059] The memory 503 is used to store program code for executing the solution of the present application, and is controlled by the processor 501. The processor 501 is used to execute the program code stored in the memory 503. The program code may include one or more software modules. The method used in the above embodiment can be implemented by the processor 501 and one or more software modules in the program code in the memory 503.

[0060] The communication interface 504 uses any device such as a transceiver to communicate with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area network (WLAN), etc.

[0061] In a specific implementation, as an example, a computer device may include multiple processors, each of which may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. A processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0062] The aforementioned computer device can be a general-purpose computer device or a dedicated computer device. In a specific implementation, the computer device can be a desktop computer, a portable 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 this application do not limit the type of computer device.

[0063] In addition, the present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned lightning protection device current leakage detection method is implemented.

[0064] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0065] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for detecting current leakage of a lightning protection device, wherein: An array of rotating electromagnetic field detection probes is deployed near a lightning protection device, and a controllable rotating electromagnetic field is applied to a detection area of ​​the lightning protection device during detection. The method is characterized in that it includes the following steps: collecting electromagnetic field response signals of the detection probe array under rotational excitation; decomposing the electromagnetic field response signal into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments, and dividing the surface of the lightning protection device into a plurality of current detection blocks based on geometric structure information of the lightning protection device; 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 based on the field strength coupling relationship combined with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment to obtain a density inversion field of the current on the surface of the lightning protection device at the rotation moment, thereby obtaining a density inversion field of the current on the surface of the lightning protection device at each rotation moment; A current density topology map of the leakage current of the lightning protection device is generated based on all density inversion fields, and then the leakage current position of the lightning protection device is located according to the current density abnormal area in the current density topology map.

2. The method according to claim 1, wherein Decomposing the electromagnetic field response signal into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments specifically includes: obtaining different rotation moments of the rotating electromagnetic field; selecting a 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; determining an equivalent uniform field response signal corresponding to the rotating electromagnetic field at a selected rotation moment based on the electromagnetic field response signal segment; Continue to determine the equivalent uniform field response signal corresponding to the rotating electromagnetic field at the remaining rotation moments.

3. The method according to claim 1, wherein 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: Acquiring geometric structure information of the lightning protection device; determining a surface division principle of the lightning protection device according to the geometric structure information; The surface of the lightning protection device is divided into a plurality of current detection blocks according to the surface division principle.

4. The method according to claim 1, wherein 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 a field strength coupling relationship between the surface of the lightning protection device and the detection probes in the detection probe array specifically includes: Obtain the position coordinates of each current detection block; Calculating the induced field strength of the 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; Acquiring a correspondence between each current detection block and the detection probes in the detection probe array; A field strength coupling relationship is formed between the surface of the lightning protection device and the detection probes in the detection probe array according to the corresponding relationship and all the induced field strengths.

5. The method according to claim 1, wherein Performing density inversion on the current on 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 moment to obtain the density inversion field of the current on the surface of the lightning protection device at the rotation moment specifically includes: Determining the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment; Determining a field intensity vector between the surface of the lightning protection device and a detection probe in the detection probe array according to the field intensity coupling relationship and the frequency domain characteristics; reconstructing the current density of each current detection block through the field intensity vector; A density inversion field of the current on the surface of the lightning protection device at the rotation moment is determined according to all current densities.

6. The method according to claim 1, wherein Generating the current density topology map of the lightning protection device leakage current based on all density inversion fields specifically includes: Based on the position characteristics of each current detection block, all density inversion fields are superimposed and integrated to obtain a current density superposition map of the lightning protection device; A current density topology diagram of the leakage current of the lightning protection device is determined according to the current density superposition diagram.

7. The method according to claim 1, wherein Locating the leakage current position of the lightning protection device based on the current density abnormal area in the current density topology map specifically includes: Obtaining the normal range and distribution pattern of surface current density of the lightning protection device; Determining a current density abnormal area in the current density topology map according to a normal range and distribution pattern of the current density; The leakage current position of the lightning protection device is determined through the abnormal current density area.

8. The method according to claim 1, wherein A three-dimensional laser scanner is used to obtain geometric structure information of the lightning protection device.

9. The method according to 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, characterized in that: include: An acquisition module, configured to acquire an electromagnetic field response signal of the detection probe array under rotational excitation; a processing module, configured to decompose the electromagnetic field response signal into equivalent uniform field response signals corresponding to the rotating electromagnetic field at different rotation moments, and divide the surface of the lightning protection device into a plurality of current detection blocks based on geometric structure information of the lightning protection device; The processing module is further configured to calculate, for each rotation moment, the induced field strength of each current detection block 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; perform density inversion on the current on the surface of the lightning protection device based on the field strength coupling relationship in combination with the frequency domain characteristics of the equivalent uniform field response signal corresponding to the rotation moment, thereby obtaining a density inversion field of the current on the surface of the lightning protection device at the rotation moment, and further obtaining a density inversion field of the current on the surface of the lightning protection device at each rotation moment; An execution module is used to generate a current density topology map of the leakage current of the lightning protection device based on all density inversion fields, and then locate the leakage current position of the lightning protection device according to the current density abnormal area in the current density topology map.

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