A real-time monitoring method and system for the power frequency resistance of a 27.5kV cable section grounding grid in traction power supply

Abstract

The present invention relates to the technical field of real-time monitoring of power frequency resistance, and provides a real-time monitoring method and system for the power frequency resistance of a 27.5kV cable section grounding network for traction power supply. The method and system obtain temperature distribution data on the surface of a conductor of the grounding network; collect voltage and current responses of the grounding network when a local temperature rise value exceeds a preset reference value, perform frequency domain conversion, and generate a broadband impedance spectrum analysis result; align the surface coordinates corresponding to the temperature measurement nodes with the underground coordinates corresponding to the impedance measurement points to generate a spatial correlation grid, generate a temperature rise phase offset coupling relationship matrix, and generate real-time monitoring results of the power frequency resistance of the grounding network based on the power frequency impedance correction value therein; the present invention achieves precise spatial matching between abnormal temperature rise areas and corresponding conductor impedance changes, enhances the adaptability of the monitoring network to changes in conductor extension direction and burial depth, and avoids omission of characteristic signals caused by the deployment of fixed measurement points.

Description

Technical Field

[0001] The present invention relates to the technical field of real-time monitoring of power frequency resistance, and in particular to a method and system for real-time monitoring of power frequency resistance of a 27.5 kV cable section grounding network for traction power supply. Background Art

[0002] During the operation of 27.5kV cable-section grounding grids for traction power supply systems, the grounding conductors are prone to abnormal temperature rises in localized areas due to long-term exposure to high-frequency transient currents and persistent unbalanced currents. This in turn causes changes in grounding resistance, threatening the safe operation of the system. Especially in situations where cable sections are long and the geological environment is complex, a technology that can perform real-time monitoring of the grounding grid's power frequency resistance in complex electromagnetic environments is needed to improve the reliability and intelligent operation and maintenance of the traction power supply system.

[0003] The current mainstream approach is a grounding grid condition assessment method based on a combination of broadband excitation and multi-point impedance measurement. This method applies broadband excitation signals at different locations on the grounding grid and collects the voltage and current responses at each impedance measurement point to establish an impedance distribution model for the entire grounding grid. By combining historical data analysis with current operating conditions, the changing trend of the grounding grid's overall resistance is deduced to preliminarily locate abnormal areas. Existing solutions have several inherent flaws, including their reliance on changes in a single electrical parameter to determine the grounding grid's condition, which limits the accuracy of identifying power-frequency resistance changes in complex operating environments. Furthermore, the method lacks effective integration of spatial geographic information, hindering the ability to accurately restore and monitor the grounding grid's true operating status in real time. Summary of the Invention

[0004] The present invention provides a real-time monitoring method and system for the power-frequency resistance of a 27.5kV cable section grounding grid for traction power supply, aiming to address the problems in the prior art of relying on a single electrical parameter change to judge the grounding grid status, resulting in limited accuracy in identifying power-frequency resistance changes in complex operating environments; and a lack of effective integration of spatial geographic information, which affects the ability to accurately restore the actual operating status of the grounding grid and monitor it in real time.

[0005] In a first aspect, the present invention provides a method for real-time monitoring of the power frequency resistance of a grounding network in a 27.5 kV cable section of a traction power supply, comprising:

[0006] Acquire temperature distribution data on the conductor surface of a grounding grid within a 27.5 kV traction power cable section, wherein the grounding grid includes a plurality of temperature measurement nodes arranged at equal intervals within the 27.5 kV traction power cable section;

[0007] collecting voltage and current responses of the grounding grid when a local temperature rise value exceeds a preset reference value, performing frequency domain conversion on the voltage and current responses to generate a broadband impedance spectrum analysis result, wherein the local temperature rise value is obtained from the temperature distribution data;

[0008] According to the conductor topology of the grounding grid, the surface coordinates corresponding to the temperature measurement nodes are aligned with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis results to generate a spatial correlation grid;

[0009] Extracting the temperature rise rate extreme value from the spatial correlation grid, extracting the phase offset extreme value from the broadband impedance spectrum analysis result, and combining the temperature rise rate extreme value and the phase offset extreme value to generate a temperature rise phase offset coupling relationship matrix;

[0010] A real-time monitoring result of the power frequency resistance of the grounding grid is generated according to the power frequency impedance correction value of the temperature rise phase shift coupling relationship matrix.

[0011] Optionally, according to the conductor topology of the grounding grid, the surface coordinates corresponding to the temperature measurement nodes are aligned with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis results to generate a spatial correlation grid, including:

[0012] According to the conductor topology of the grounding grid, the length of the conductor segment, the location of the branch connection point, and the vertical coordinate of the conductor buried depth corresponding to the location of the branch connection point are obtained;

[0013] Determining the actual installation position of the temperature measurement node according to the conductor segment and the position of the branch connection point;

[0014] Filtering the frequency interval in which the impedance amplitude in the conductor segment decreases by more than a preset decrease value from the broadband impedance spectrum analysis result, and determining the coordinate point of the position with the maximum current density in the conductor segment as the impedance measurement point based on the current distribution characteristics corresponding to the frequency interval;

[0015] The surface coordinates corresponding to the actual installation position of the temperature measurement node, the vertical coordinates of the conductor burial depth, and the underground coordinates corresponding to the impedance measurement point are bound to generate a spatial correlation grid.

[0016] Optionally, binding the surface coordinates corresponding to the actual installation position of the temperature measurement node, the vertical coordinates of the conductor burial depth, and the underground coordinates corresponding to the impedance measurement point to generate a spatial correlation grid includes:

[0017] Based on the length of the conductor segment and the location of the branch connection point, the grounding grid is divided into a plurality of conductor segment units, wherein each conductor segment unit includes a temperature measurement node and an impedance measurement point;

[0018] Superimposing the surface coordinates corresponding to the actual installation position of the temperature measurement node in each conductor segment unit with the vertical coordinates of the conductor burial depth to generate the three-dimensional monitoring coordinates corresponding to the temperature measurement node in each conductor segment unit;

[0019] According to the underground coordinates corresponding to the impedance measurement points in each conductor segment unit, the underground coordinates corresponding to the impedance measurement points in each conductor segment unit are spatially bound with the corresponding three-dimensional monitoring coordinates to generate a bound coordinate pair for each conductor segment unit;

[0020] Aggregating the bound coordinate pairs of multiple conductor segment units adjacent to the branch connection point with the vertical coordinate of the conductor burial depth to generate a branch topology node;

[0021] The binding coordinate pairs and the branch topology nodes are mapped to generate a spatial association grid.

[0022] Optionally, collecting voltage and current responses of the grounding grid when a local temperature rise value exceeds a preset reference value, performing frequency domain conversion on the voltage and current responses to generate a broadband impedance spectrum analysis result, wherein the local temperature rise value is obtained from the temperature distribution data, includes:

[0023] When the temperature rise value of at least one temperature measurement node in the temperature distribution data exceeds a preset reference value, it is determined that there is a local temperature rise abnormality in the grounding grid, and the voltage and current time domain waveform data at both ends of the grounding grid under the excitation signal are collected;

[0024] Dividing the voltage and current time domain waveform data into a plurality of time domain data segments according to a preset time period, and removing the time domain data segments whose waveform distortion rate exceeds a preset distortion threshold, so as to generate optimized voltage and current time domain waveform data;

[0025] Performing a windowed Fourier transform on each time domain data segment in the optimized voltage and current time domain waveform data to obtain a voltage spectrum and a current spectrum corresponding to each time domain data segment;

[0026] Extracting the voltage effective value of each discrete frequency point from the voltage spectrum, and extracting the current effective value corresponding to the discrete frequency point from the current spectrum, so as to calculate the voltage-current phase difference and impedance amplitude corresponding to each discrete frequency point;

[0027] Associating the voltage and current phase difference, impedance amplitude and frequency value corresponding to each discrete frequency point into an impedance spectrum data entry;

[0028] All impedance spectrum data entries are arranged in ascending order of frequency value to generate broadband impedance spectrum analysis results. During the arrangement process, impedance spectrum data entries with the same frequency value are merged, and abnormal entries with impedance amplitude fluctuations exceeding the preset range are eliminated.

[0029] Optionally, performing a windowed Fourier transform on each time domain data segment in the optimized voltage and current time domain waveform data to obtain a voltage spectrum and a current spectrum corresponding to each time domain data segment includes:

[0030] Multiplying the voltage waveform data and the current waveform data in each time domain data segment of the optimized voltage and current time domain waveform data by a preset window function point by point to generate windowed voltage waveform segments and current waveform segments;

[0031] Determining a discrete frequency point set according to the duration and sampling interval of the time domain data segment;

[0032] Based on the discrete frequency point set, discrete spectrum conversion is performed on the windowed voltage waveform segment and current waveform segment to obtain a voltage spectrum sequence and a current spectrum sequence;

[0033] Extracting the voltage real part value and the first imaginary part value of each discrete frequency point from the voltage spectrum sequence to calculate the effective value of the voltage at each discrete frequency point;

[0034] Extracting the current real part value and the second imaginary part value corresponding to the discrete frequency point from the current spectrum sequence to calculate the effective value of the current at each discrete frequency point;

[0035] Calculate the voltage and current phase difference at each discrete frequency point based on the voltage real part value, current real part value, voltage imaginary part value and current imaginary part value at each discrete frequency point;

[0036] The voltage RMS value, current RMS value, and voltage-current phase difference of each discrete frequency point are bound to the corresponding frequency value to obtain multiple spectrum entries. The multiple spectrum entries are sorted to generate the voltage spectrum and current spectrum corresponding to each time domain data segment.

[0037] Optionally, extracting the temperature rise rate extreme value from the spatial correlation grid, extracting the phase offset extreme value from the broadband impedance spectrum analysis result, and combining the temperature rise rate extreme value and the phase offset extreme value to generate a temperature rise phase offset coupling relationship matrix, including:

[0038] Extracting the temperature rise rate extreme value of each temperature measurement node within a preset time window from the spatial correlation grid;

[0039] Extracting the phase offset extreme value corresponding to each impedance measurement point from the broadband impedance spectrum analysis result;

[0040] According to the binding relationship between the conductor segment units and the temperature measurement nodes and the impedance measurement points in the spatial correlation grid, the temperature rise rate extreme value and the phase offset extreme value corresponding to each conductor segment unit are associated to generate a coupling parameter pair;

[0041] Based on the conductor topology of the grounding grid, the coupling parameter pairs corresponding to each conductor segment unit are mapped to the rows and columns of a preset matrix to generate a temperature rise phase shift coupling relationship matrix.

[0042] Optionally, generating a real-time monitoring result of the power frequency resistance of the grounding grid according to the power frequency impedance correction value of the temperature rise phase shift coupling relationship matrix includes:

[0043] Screening out a plurality of target matrix elements from the temperature rise phase offset coupling relationship matrix, and using the target matrix elements as key correction factors, wherein the target matrix elements are matrix elements whose extreme values ​​of temperature rise rate and phase offset both exceed preset thresholds;

[0044] Calculate the weight coefficient of each key correction factor based on the proportional relationship between the temperature rise rate extreme value and the phase offset extreme value corresponding to each key correction factor;

[0045] According to the weight coefficient, each key correction factor is superimposed to generate a power frequency impedance region correction value;

[0046] The power frequency impedance region correction value is mapped to the corresponding conductor segment unit in the spatial correlation grid to generate a real-time monitoring result of the power frequency resistance of the grounding grid.

[0047] In a second aspect, the present invention provides a real-time monitoring system for the power frequency resistance of a 27.5 kV cable section grounding network for traction power supply, comprising:

[0048] An acquisition module, configured to acquire temperature distribution data of a conductor surface of a grounding grid within a 27.5 kV traction power supply cable section, the grounding grid comprising a plurality of temperature measurement nodes equally spaced along the 27.5 kV traction power supply cable section;

[0049] a conversion module, configured to collect voltage and current responses of the grounding grid when a local temperature rise value exceeds a preset reference value, and perform frequency domain conversion on the voltage and current responses to generate a broadband impedance spectrum analysis result, wherein the local temperature rise value is obtained from the temperature distribution data;

[0050] an alignment module, configured to align the surface coordinates corresponding to the temperature measurement nodes with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis results according to the conductor topology of the grounding grid, thereby generating a spatial correlation grid;

[0051] an extraction module, configured to extract temperature rise rate extremes from the spatial correlation grid, extract phase offset extremes from the broadband impedance spectrum analysis results, and generate a temperature rise phase offset coupling relationship matrix by combining the temperature rise rate extremes and the phase offset extremes;

[0052] A generating module is used to generate a real-time monitoring result of the power frequency resistance of the grounding grid according to the power frequency impedance correction value of the temperature rise phase shift coupling relationship matrix.

[0053] In a third aspect, the present invention provides a computing device comprising a processor and a memory, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute a real-time monitoring method for the power frequency resistance of a 27.5kV cable section grounding network for traction power supply as described in any one of the first aspects.

[0054] In a fourth aspect, the present invention provides a computer storage medium having computer program instructions stored thereon, which, when executed by a processor, implements a method for real-time monitoring of the power frequency resistance of a traction power supply 27.5kV cable section grounding network as described in any one of the first aspects.

[0055] In the present invention, temperature distribution data of the conductor surface of the grounding grid in the 27.5kV traction power supply cable section is obtained, and the grounding grid includes multiple temperature measurement nodes arranged at equal intervals along the 27.5kV traction power supply cable section; the voltage and current responses of the grounding grid when the local temperature rise value exceeds a preset reference value are collected, and the voltage and current responses are converted into the frequency domain to generate a broadband impedance spectrum analysis result, and the local temperature rise value is obtained from the temperature distribution data; according to the conductor topology of the grounding grid, the surface coordinates corresponding to the temperature measurement nodes are aligned with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis result to generate a spatial correlation grid; the temperature rise rate extreme value is extracted from the spatial correlation grid, and the phase offset extreme value is extracted from the broadband impedance spectrum analysis result, and the temperature rise rate extreme value and the phase offset extreme value are combined to generate a temperature rise phase offset coupling relationship matrix; according to the power frequency impedance correction value of the temperature rise phase offset coupling relationship matrix, a real-time monitoring result of the power frequency resistance of the grounding grid is generated. The technical solution provided by the present invention realizes full coverage monitoring of the surface temperature of the grounding grid through temperature measurement nodes deployed at equal intervals, overcoming the defect of traditional single-point temperature measurement that has a delayed response to local abnormal temperature rise; by capturing the high-frequency current response triggered by local temperature rise, it effectively identifies changes in the distributed parameters of the grounding grid, and enhances the detection sensitivity of hidden defects such as conductor degradation and local fracture; based on the topological structure, three-dimensional spatial mapping of surface temperature monitoring points and underground impedance measurement points is realized, solving the spatial mismatch problem between ground temperature data and underground electrical parameters in the existing technology; by coupling the temperature change rate and impedance phase offset characteristics, the nonlinear correlation law between the conductor temperature rise and electrical parameters is revealed, breaking through the limitation of the traditional method of isolated analysis of thermoelectric parameters; through the power frequency impedance correction mechanism of the coupling matrix, the influence of high-frequency components on the power frequency resistance calculation is eliminated, and the reliability of grounding grid status assessment in strong electromagnetic interference environment is improved. Among them, by breaking through the technical barriers of spatial separation of ground temperature data and underground electrical state in traditional grounding grid monitoring, accurate spatial matching of abnormal temperature rise areas and corresponding conductor impedance changes is achieved; by dynamically binding impedance measurement points and conductor segment physical properties, the monitoring network's adaptability to changes in conductor extension direction and burial depth is enhanced, avoiding the omission of characteristic signals caused by the deployment of fixed measurement points.

[0056] These and other aspects of the present invention will become more readily apparent from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0058] Figure 1 A flowchart of a method for real-time monitoring of the power frequency resistance of a 27.5kV cable section grounding network for traction power supply provided by an embodiment of the present invention;

[0059] Figure 2 A schematic diagram of the structure of a real-time monitoring system for the power frequency resistance of a 27.5kV cable section grounding network for traction power supply provided by an embodiment of the present invention;

[0060] Figure 3 A schematic diagram of the structure of a computing device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0062] In some of the processes described in the specification and claims of the present invention and the above-mentioned figures, multiple operations that appear in a specific order are included, but it should be clearly understood that these operations may not be executed in the order in which they appear in this article or may be executed in parallel. The serial numbers of the operations, such as 101, 102, etc., are only used to distinguish between different operations, and the serial numbers themselves do not represent any execution order. In addition, these processes may include more or fewer operations, and these operations may be executed in sequence or in parallel. It should be noted that the descriptions of "first", "second", etc. in this article are used to distinguish different messages, devices, modules, etc., and do not represent the order of precedence, nor do they limit "first" and "second" to be different types.

[0063] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0064] Figure 1 The present invention provides a flowchart of a method for real-time monitoring of the power frequency resistance of a 27.5kV cable section grounding network for traction power supply, as shown in FIG. Figure 1 As shown, the method includes:

[0065] Aiming at the problem that distributed temperature rise anomalies caused by conductor corrosion and poor contact in the traction power supply cable section grounding network are difficult to monitor in real time, the traditional method is limited by single-point temperature detection and cannot correlate local overheating with power frequency resistance changes, and the power frequency impedance measurement is susceptible to electromagnetic interference and leads to misjudgment. The existing technology lacks a spatial matching mechanism for the underground conductor topology and the surface temperature field, resulting in ambiguous fault location. The present invention realizes dynamic perception of the temperature field through equidistant temperature measurement nodes, collects broadband impedance spectra when local temperature rise is triggered to capture the high-frequency characteristics of conductor degradation, combines the conductor topology to bind the surface temperature rise points and underground impedance measurement points in three dimensions, constructs a coupling matrix of temperature rise rate and phase offset, and finally eliminates interference through dynamic correction of power frequency impedance, forming a real-time monitoring solution for grounding network resistance that takes into account both spatial accuracy and anti-interference, breaking through the technical bottleneck of traditional methods in complex underground structure scenarios such as multi-parameter mismatch and missed detection of hidden defects. Based on this, the present invention provides a real-time monitoring method for the power frequency resistance of the traction power supply 27.5kV cable section grounding network, such as Figure 1 ,include:

[0066] Step 101: Acquire temperature distribution data of the conductor surface of the grounding grid in the traction power supply 27.5 kV cable section, wherein the grounding grid includes a plurality of temperature measurement nodes arranged at equal intervals along the traction power supply 27.5 kV cable section.

[0067] In this step, the temperature distribution data refers to the surface temperature of the grounding grid conductor collected periodically by temperature measurement nodes deployed at equal intervals. It includes the geographic coordinates, temperature value and timestamp of each node, which is used to reflect the local overheating anomaly of the conductor.

[0068] In this embodiment, multiple temperature measurement nodes (such as distributed fiber optic sensors or infrared temperature measurement devices) are evenly spaced along the 27.5kV traction power cable section to collect real-time temperature data from the surface of the grounding grid conductor, generating temperature distribution data covering the entire cable section. This data includes the geographic coordinates of each temperature measurement node and its corresponding temperature value. Periodic data upload (for example, sampling every 10 seconds) is used to construct a dynamic temperature field model.

[0069] Step 102: collecting voltage and current responses of the grounding grid when a local temperature rise value exceeds a preset reference value, performing frequency domain conversion on the voltage and current responses to generate broadband impedance spectrum analysis results, wherein the local temperature rise value is obtained from the temperature distribution data.

[0070] In this step, the voltage and current response refers to the time-domain waveform data of voltage and current generated by the grounding grid under an external excitation signal (swept frequency or pulse), which is used to characterize the conductor impedance characteristics; the frequency domain conversion operation refers to the process of converting the time-domain voltage and current signals into a frequency-domain impedance spectrum through fast Fourier transform (FFT), including the calculation between the amplitude obtained by dividing the voltage amplitude by the current amplitude and the phase obtained by subtracting the current phase from the voltage phase; the broadband impedance spectrum analysis result refers to the impedance amplitude and phase angle curve covering the frequency range of 1Hz-10MHz, which is used to identify the resonant frequency offset caused by conductor degradation.

[0071] In an embodiment of the present invention, when it is detected that the local temperature rise value exceeds a preset reference value (for example, the ambient temperature +15°C), a high-frequency voltage and current acquisition device (such as a wide-band mutual inductor) is triggered to inject a swept frequency signal (1Hz-10MHz) into the grounding grid, and the voltage and current time domain waveforms are synchronously acquired. The time domain signal is converted into the frequency domain through a fast Fourier transform (FFT) to generate a wide-band impedance spectrum analysis result containing amplitude-frequency characteristics and phase-frequency characteristics. The result is stored in the form of a two-dimensional curve with frequency as the horizontal axis and impedance amplitude and phase angle as the vertical axis. The analysis focuses on the frequency band where the impedance amplitude drops by more than 30% (reflecting the conductor degradation characteristics).

[0072] Step 103: Based on the conductor topology of the grounding grid, align the surface coordinates corresponding to the temperature measurement nodes with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis results to generate a spatial correlation grid.

[0073] In this step, the alignment operation refers to the geometric association process of binding the surface temperature measurement points and the underground impedance measurement points to the same conductor segment through three-dimensional spatial coordinate mapping; the spatial association grid refers to a three-dimensional grid unit based on the conductor topology segmentation, each unit contains the bound temperature, impedance data and conductor property parameters.

[0074] In an embodiment of the present invention, based on the conductor topology of the grounding grid (including conductor segment lengths, branch connection point coordinates, and burial depth parameters), the surface plane coordinates (x, y) of the temperature measurement node and the vertical coordinates (z) of the conductor burial depth are combined into three-dimensional coordinates (x, y, z). Simultaneously, the point of maximum current density within the conductor segment (the underground coordinate corresponding to the point of lowest impedance amplitude) is extracted from the broadband impedance spectrum. Using a spatial matching algorithm of a geographic information system (GIS), the coordinates of the surface temperature measurement node and the coordinates of the underground impedance measurement point are three-dimensionally aligned to generate a gridded spatial model containing a temperature-impedance correlation relationship, in which each grid cell is bound to temperature data, impedance data, and conductor physical properties.

[0075] Step 104: extracting temperature rise rate extreme values ​​from the spatial correlation grid, extracting phase offset extreme values ​​from the broadband impedance spectrum analysis results, and combining the temperature rise rate extreme values ​​and the phase offset extreme values ​​to generate a temperature rise phase offset coupling relationship matrix.

[0076] In this step, the phase shift extreme value refers to the maximum deviation (Δθ) of the phase angle relative to the reference value in the broadband impedance spectrum, reflecting the change in the dielectric properties of the conductor.

[0077] Temperature rise phase shift coupling matrix: refers to a two-dimensional data table with spatial grids as units that quantifies the nonlinear relationship between temperature rise rate and phase shift, used for power frequency impedance correction.

[0078] In an embodiment of the present invention, the temperature rise rate extreme value (maximum temperature change rate ΔT / Δt) and the corresponding phase offset extreme value (maximum phase angle change Δθ) in the broadband impedance spectrum of each grid cell are extracted from the spatially correlated grid. Through multivariate regression analysis, a nonlinear relationship function between the temperature rise rate and the phase offset is established and expressed in matrix form as follows: coupling coefficient = temperature rise rate extreme value × phase offset extreme value / reference temperature rise threshold.

[0079] Step 105: generating a real-time monitoring result of the power frequency resistance of the grounding grid according to the power frequency impedance correction value of the temperature rise phase shift coupling relationship matrix.

[0080] In this step, the power frequency impedance correction value refers to the dynamic compensation of the impedance value in the 50 Hz power frequency band through the coupling matrix to eliminate the influence of temperature rise and high-frequency interference; the power frequency resistance refers to the equivalent resistance value of the grounding grid at 50 Hz after correction, which is used to evaluate the safety status of the grounding grid.

[0081] In an embodiment of the present invention, dynamic compensation is performed on the traditional power-frequency resistance measurement value based on the power-frequency impedance correction value (coupling coefficient × power-frequency impedance reference value) of each grid unit in the temperature-rise phase-shift coupling matrix. Specifically, a weighted average algorithm is adopted to fuse the correction values ​​of each grid according to the proportion of conductor length to generate a power-frequency resistance value that eliminates the influence of high-frequency interference and temperature rise, and finally outputs the real-time monitoring results of the overall and segmented resistance of the grounding grid.

[0082] For example, in the cable tunnel of a traction substation, fiber-optic temperature measurement nodes are deployed every 5 meters along the 27.5kV grounding grid. When a node detects a temperature rise of 25°C (ambient reference 10°C), a broadband signal source is triggered to inject a 1-100kHz swept frequency signal, synchronously acquiring voltage and current waveforms. An impedance spectrum is generated through FFT, identifying a 42% drop in impedance amplitude at the 2.4kHz frequency point, which is used to locate the conductor degradation point 1.2m underground. The temperature rise rate of 0.8°C / s and the phase offset of 28° in this area are extracted to generate a grid cell with a coupling coefficient of 0.45. Finally, the power frequency impedance is corrected according to the coupling coefficient, outputting an actual resistance value of 0.85Ω (traditional measurement is 1.2Ω), accurately reflecting the corrosion status of the conductor.

[0083] This embodiment of the present invention achieves full temperature field monitoring through equally spaced temperature measurement nodes, combining broadband impedance spectrum analysis to overcome the limitations of traditional power-frequency measurement. A spatially correlated grid based on conductor topology addresses the mismatch between ground temperature and underground electrical parameters. A temperature-rise phase-shift coupling matrix reveals hidden defect characteristics, ultimately improving the accuracy of power-frequency resistance measurements through dynamic correction. This overall solution significantly increases the early detection rate of faults such as localized corrosion and poor contact in complex grounding networks, and enhances immunity to strong electromagnetic interference.

[0084] The present invention provides a specific embodiment, in which step 103, based on the conductor topology of the grounding grid, the surface coordinates corresponding to the temperature measurement nodes are aligned with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis results to generate a spatial correlation grid, specifically comprising the following steps:

[0085] Step 301: According to the conductor topology of the grounding grid, the length of the conductor segment, the location of the branch connection point, and the vertical coordinate of the conductor buried depth corresponding to the location of the branch connection point are obtained.

[0086] In this step, the conductor topology refers to the physical connection and spatial distribution relationship of the grounding grid conductors, including the connection method, number of branches and direction between conductor segments, which is used to define the logical framework of the monitoring network; conductor segments refer to independent conductor segments separated by branch connection points in the grounding grid, and their lengths and spatial coordinates constitute the basic units of the topological structure; branch connection points refer to the intersection of three or more conductor segments in the grounding grid, and their three-dimensional coordinates determine the conductor extension direction and monitoring node deployment strategy.

[0087] In an embodiment of the present invention, based on the conductor topology of the grounding grid (i.e., the physical connections and spatial distribution of the conductors), the lengths of the conductor segments, the locations of the branch connection points, and the vertical coordinates of the conductor burial depths corresponding to the branch connection points are obtained by parsing grounding grid design drawings or 3D modeling data. Specifically, the conductor burial depth parameters are extracted using BIM (Building Information Modeling) tools or underground pipeline detection equipment, and the data is formatted into a topological database containing segment numbers, coordinates, and burial depths.

[0088] Step 302: Determine the actual installation position of the temperature measurement node according to the conductor segment and the branch connection point position.

[0089] In this step, the actual installation location refers to the temperature measurement node deployment coordinates calculated based on the conductor segment length and branch connection point location to ensure that the key monitoring areas along the entire length of the conductor are covered.

[0090] In this embodiment of the present invention, a spacing calculation algorithm is used to determine the actual installation location of the temperature measurement node based on the conductor segment length and the location of the branch connection point. For straight conductor segments, the number of nodes is calculated by dividing the segment length by the preset spacing, and they are deployed equidistantly along the conductor extension direction. For branch connection points, the location extending a preset distance from the point to the three adjacent conductor segments is used as the installation point to avoid nodes directly overlapping the connection point and causing signal interference. The installation location coordinates are calibrated on-site using GPS or a total station and associated with the conductor topology database.

[0091] Step 303: Filter out the frequency interval in which the impedance amplitude in the conductor segment decreases by more than a preset decrease value from the broadband impedance spectrum analysis results, and determine the coordinate point of the position with the maximum current density in the conductor segment as the impedance measurement point based on the current distribution characteristics corresponding to the frequency interval.

[0092] In this step, the impedance amplitude refers to the ratio of the voltage to the current amplitude at a specific frequency in the broadband impedance spectrum, reflecting the conductive performance of the conductor at this frequency; the frequency interval refers to the continuous frequency band in which the impedance amplitude drops by more than a preset threshold in the broadband impedance spectrum, which is used to locate the resonance characteristics caused by conductor degradation; the current distribution characteristic refers to the spatial distribution law of the current density on the conductor cross section, which is obtained through electromagnetic field simulation calculation and is used to determine the location of the current concentration area; the impedance measurement point is the underground three-dimensional coordinate corresponding to the position of the maximum current density in the conductor segment, reflecting the potential fault point of conductor degradation or fracture.

[0093] In an embodiment of the present invention, a frequency interval (e.g., 2-5 kHz) in which the impedance amplitude decreases by more than a preset decrease value (e.g., 30%) within a conductor segment is screened from the results of a broadband impedance spectrum analysis, and the current density distribution of the conductor cross section is calculated by finite element electromagnetic simulation to extract the current distribution characteristics of each frequency point within the interval. Based on the spatial coordinate point corresponding to the maximum current density (current density = total current of the conductor segment / cross-sectional area), combined with the geometric parameters of the conductor segment, such as length or direction, the precise coordinates of the point in the underground three-dimensional space are determined and marked as the impedance measurement point.

[0094] Step 304: Bind the surface coordinates corresponding to the actual installation position of the temperature measurement node, the vertical coordinates of the conductor burial depth, and the underground coordinates corresponding to the impedance measurement point to generate a spatial correlation grid.

[0095] In this step, the vertical coordinate of the conductor burial depth indicates the vertical depth value of the conductor from the ground surface, which is obtained through underground detection or design drawings and is used to construct a three-dimensional monitoring network; the binding operation refers to the data fusion process of spatially associating the surface temperature measurement node coordinates, the conductor burial depth coordinates and the underground impedance measurement point coordinates to establish a multi-dimensional mapping relationship between temperature, impedance and position.

[0096] In an embodiment of the present invention, the surface plane coordinates (x, y) of the actual installation location of the temperature measurement node, the vertical coordinates (z) of the conductor burial depth, and the underground coordinates (x', y', z') of the impedance measurement point are bound. That is, through a spatial coordinate conversion algorithm, the surface plane coordinates are vertically projected onto the plane corresponding to the conductor burial depth z, and the horizontal offset between the plane and the impedance measurement point is calculated. If the offset is less than a preset threshold, it is determined to be the same conductor segment association point, and finally a spatial association grid containing the temperature-impedance-position mapping relationship is generated.

[0097] The embodiments of the present invention accurately calculate the deployment positions of temperature measurement nodes through the conductor topology structure, avoiding monitoring blind spots caused by blind deployment; dynamically locate underground conductor degradation points by combining broadband impedance spectrum screening and current density analysis; and construct a spatial correlation grid through three-dimensional coordinate binding to achieve spatial consistency matching between surface temperature data and underground electrical parameters, significantly improving the fault location accuracy of complex branch structure grounding networks and solving the problem of characteristic signal omission caused by the deployment of fixed measurement points in traditional methods.

[0098] The present invention provides a specific embodiment, step 304, binding the surface coordinates corresponding to the actual installation location of the temperature measurement node, the vertical coordinates of the conductor burial depth, and the underground coordinates corresponding to the impedance measurement point to generate a spatial correlation grid, specifically including the following steps:

[0099] Step 341: Based on the length of the conductor segment and the location of the branch connection point, the grounding grid is divided into a plurality of conductor segment units, wherein each conductor segment unit includes a temperature measurement node and an impedance measurement point.

[0100] In this step, the conductor segment unit refers to an independent monitoring area divided according to the conductor segment length and branch connection point, including at least one temperature measurement node and one impedance measurement point, which is used to construct a minimum monitoring unit.

[0101] In an embodiment of the present invention, a grid partitioning algorithm is used to divide the grounding grid into multiple conductor segment units based on the length of the conductor segment and the position of the branch connection point, wherein the boundary of each conductor segment unit is determined by the branch connection points at both ends of the conductor segment, and each unit is required to contain at least one temperature measurement node and one impedance measurement point; for straight conductor segments, the unit length is equal to the conductor segment length; for adjacent areas of branch connection points, the unit boundary extends to 1 / 3 of the adjacent segment length to ensure spatial correlation continuity at the branch.

[0102] Step 342: superimpose the surface coordinates corresponding to the actual installation position of the temperature measurement node in each conductor segment unit with the vertical coordinates of the conductor burial depth to generate three-dimensional monitoring coordinates corresponding to the temperature measurement node in each conductor segment unit.

[0103] In this step, the overlay operation refers to the data fusion process of combining the surface plane coordinates (x, y) and the conductor buried depth vertical coordinates (z) into three-dimensional coordinates (x, y, z), which is used to establish a three-dimensional monitoring benchmark; three-dimensional monitoring coordinates refer to the three-dimensional coordinates that fuse the surface position and buried depth information, reflecting the precise position of the temperature measurement node in the three-dimensional space of the grounding grid.

[0104] In an embodiment of the present invention, the surface plane coordinates (x, y) corresponding to the actual installation position of the temperature measurement node in each conductor segment unit are superimposed with the vertical coordinates (z) of the conductor burial depth, that is, the three-dimensional coordinate system conversion formula: (x, y, z) = (surface x, surface y, burial depth z) is used to generate the three-dimensional monitoring coordinates of the temperature measurement node, where the coordinates are also associated with the number of the conductor segment unit for subsequent spatial binding.

[0105] Step 343: Based on the underground coordinates corresponding to the impedance measurement points in each conductor segment unit, spatially bind the underground coordinates corresponding to the impedance measurement points in each conductor segment unit with the corresponding three-dimensional monitoring coordinates to generate a binding coordinate pair for each conductor segment unit.

[0106] In this step, the spatial binding operation refers to the data matching process of associating the coordinates of the underground impedance measurement point with the three-dimensional coordinates of the surface temperature measurement node through distance threshold judgment; the binding coordinate pair refers to the associated data group composed of three-dimensional monitoring coordinates and impedance measurement point coordinates, which represents the spatial correspondence between the temperature impedance of the same conductor segment unit.

[0107] In this embodiment of the present invention, for each conductor segment, the underground coordinates (x', y', z') of the impedance measurement point are associated with the three-dimensional monitoring coordinates (x, y, z) through a spatial binding operation. Specifically, a Euclidean distance calculation method is used. If the horizontal projection distance between the impedance measurement point and the three-dimensional monitoring coordinate is less than 10% of the conductor segment length (for example, a threshold of 0.5 meters for a 5-meter segment length), they are determined to be the same physical location, and a binding coordinate pair ((x, y, z), (x', y', z')) is generated.

[0108] Step 344: Aggregate the bound coordinate pairs of multiple conductor segment units adjacent to the branch connection point with the vertical coordinate of the conductor burial depth to generate a branch topology node.

[0109] In this step, the aggregation operation refers to a data fusion method that takes the arithmetic average of the coordinates of multiple bound coordinate pairs to generate the center position of the branch connection point; the branch topology node refers to the three-dimensional coordinate that characterizes the spatial position of the branch connection point, which is generated by aggregating the bound coordinate pairs of adjacent conductor segment units and is used to describe the complex branch structure.

[0110] In an embodiment of the present invention, for multiple conductor segment units with adjacent branch connection points, the three-dimensional monitoring coordinates and impedance measurement point coordinates in their bound coordinate pairs are extracted, and the geometric center point is calculated through an aggregation operation. The branch topology node coordinates are obtained by the following formula: (Σ three-dimensional monitoring coordinates + Σ impedance measurement point coordinates) / (2× number of units). The calculation result is integrated with the vertical coordinates of the conductor burial depth to generate the topology node coordinates representing the branch connection point.

[0111] Step 345: Map the binding coordinate pairs and the branch topology nodes to generate a spatial association grid.

[0112] In this step, the mapping operation refers to a spatial modeling process of constructing discrete binding coordinate pairs and branch topology nodes into a continuous grid model based on a topological connection relationship.

[0113] In an embodiment of the present invention, the binding coordinate pairs and the branch topology nodes are topologically connected through a GIS spatial mapping algorithm; with the branch topology node as the hub, adjacent binding coordinate pairs are connected in series according to the conductor extension direction to form a gridded spatial model covering the entire grounding grid, and each grid node contains temperature, impedance and three-dimensional coordinate attributes.

[0114] The embodiment of the present invention achieves refined monitoring granularity by dividing the conductor into segmented units, and eliminates the surface-underground data layer separation by combining three-dimensional coordinate superposition and spatial binding; the dynamic aggregation of branch topology nodes enhances the modeling capability of complex branch structures, and the spatial correlation grid finally formed breaks through the monitoring blind spots of traditional methods in multi-branch and three-dimensional wiring scenarios of grounding grids, significantly improving the positioning accuracy of local defects and the reliability of status assessment.

[0115] The present invention provides a specific embodiment, step 102, collecting the voltage and current responses of the grounding grid when the local temperature rise value exceeds a preset reference value, performing frequency domain conversion on the voltage and current responses to generate a broadband impedance spectrum analysis result, wherein the local temperature rise value is obtained from the temperature distribution data, specifically includes the following steps:

[0116] Step 201: When the temperature rise value of at least one temperature measurement node in the temperature distribution data exceeds a preset reference value, it is determined that there is a local temperature rise anomaly in the grounding grid, and the voltage and current time domain waveform data at both ends of the grounding grid under the excitation signal are collected.

[0117] In this step, the excitation signal refers to a broadband swept-frequency signal injected into the grounding grid, with a frequency range of typically 0.1 Hz to 1 MHz, used to stimulate the electrical response of the grounding grid at different frequencies, including voltage and current signals. The voltage and current time domain waveform data refers to the original waveform data of the voltage and current at both ends of the grounding grid collected by the sensor over time, reflecting the instantaneous amplitude of the signal.

[0118] In an embodiment of the present invention, the temperature distribution data of each temperature measuring node of the grounding grid is first monitored in real time. When it is detected that the temperature rise value of at least one temperature measuring node exceeds a preset reference value (for example, the temperature rise threshold is set to 10°C), the system determines that there is a local temperature rise anomaly in the grounding grid and triggers a data acquisition action. Subsequently, an excitation signal in a preset frequency range (such as a 0.1Hz-1MHz sweep frequency signal) is injected into both ends of the grounding grid. In the case of a local temperature rise anomaly, the voltage time domain waveform data and the current time domain waveform data at both ends of the grounding grid are synchronously collected through a high-precision data acquisition card, and the two are stored with time stamp alignment.

[0119] Step 202: Divide the voltage and current time domain waveform data into multiple time domain data segments according to a preset time period, and remove the time domain data segments whose waveform distortion rate exceeds a preset distortion threshold to generate optimized voltage and current time domain waveform data.

[0120] In this step, the time domain data segment refers to the data segment obtained by dividing the continuous time domain waveform into fixed time lengths (such as 1 second), which is used for segmented processing and analysis; the waveform distortion rate refers to the degree of deviation of the time domain waveform from the ideal sine wave, which is obtained by calculating the root mean square error ratio and is used to evaluate signal quality; the optimized voltage and current time domain waveform data refers to the time domain data segment retained after waveform distortion rate screening, which has lower noise and distortion.

[0121] In an embodiment of the present invention, the voltage time-domain waveform data and the current time-domain waveform data are divided into a plurality of time-domain data segments of equal length according to a preset time period (for example, one period is one second); then, the waveform distortion rate of each time-domain data segment is calculated, that is, the waveform peak value in the time-domain data segment is compared with the peak value of the theoretical sinusoidal waveform, and the root mean square error ratio of the two is calculated. If the ratio exceeds a preset distortion threshold (for example, 5%), it is considered that the data segment has noise interference or signal distortion and is eliminated; finally, the time-domain data segment whose waveform distortion rate meets the requirements is retained to generate optimized voltage time-domain waveform data and optimized current time-domain waveform data.

[0122] Step 203: performing a windowed Fourier transform on each time domain data segment in the optimized voltage and current time domain waveform data to obtain a voltage spectrum and a current spectrum corresponding to each time domain data segment.

[0123] In this step, the windowed Fourier transform refers to an algorithm that performs a Fourier transform on a time-domain signal after windowing it, which is used to reduce spectrum leakage and extract frequency-domain features. The voltage spectrum and current spectrum refer to the frequency-domain representation of the signal obtained through the Fourier transform, including the amplitude and phase information of each frequency point.

[0124] In an embodiment of the present invention, a windowed Fourier transform is performed on each time domain data segment in the optimized voltage time domain waveform data and current time domain waveform data, that is, a Hanning window function is used to perform windowing processing on the time domain data segment to reduce spectrum leakage, and then the time domain signal is converted into a frequency domain signal through a fast Fourier transform to obtain a voltage spectrum and a current spectrum corresponding to each time domain data segment.

[0125] Step 204: extracting the voltage effective value of each discrete frequency point from the voltage spectrum, and extracting the current effective value corresponding to the discrete frequency point from the current spectrum, so as to calculate the voltage-current phase difference and impedance amplitude corresponding to each discrete frequency point.

[0126] In this step, discrete frequency points refer to frequency sampling points divided at fixed intervals in the spectrum, which are used to extract parameters at specific frequencies; the effective value of voltage and the effective value of current refer to the equivalent energy values ​​calculated by the spectrum amplitude, reflecting the average power of the signal; the voltage-current phase difference refers to the phase angle difference between the voltage and current signals at the same frequency, which is used to calculate the phase characteristics of the impedance.

[0127] In an embodiment of the present invention, the effective value of the voltage at each discrete frequency point (for example, at intervals of 1 Hz) is extracted from the voltage spectrum using a calculation formula that multiplies the square root of the voltage spectrum amplitude by a normalization coefficient. Similarly, the effective value of the current corresponding to the discrete frequency point is extracted from the current spectrum. Subsequently, the voltage-current phase difference (i.e., the voltage phase angle minus the current phase angle) is calculated for each discrete frequency point, and the impedance amplitude is calculated using a formula that divides the effective value of the voltage by the effective value of the current.

[0128] Step 205: Associating the voltage and current phase difference, impedance amplitude, and frequency value corresponding to each discrete frequency point into an impedance spectrum data entry.

[0129] In this step, the frequency value refers to the frequency parameter corresponding to the signal or impedance, and the unit is Hz.

[0130] In an embodiment of the present invention, the voltage and current phase difference, impedance amplitude, and frequency value (e.g., 50 Hz, 100 Hz, etc.) corresponding to each discrete frequency point are associated into a structured data entry, namely, an impedance spectrum data entry, where each entry contains three fields: frequency value (unit: Hz), phase difference (unit: degrees), and impedance amplitude (unit: Ω).

[0131] Step 206: Arrange all impedance spectrum data entries in ascending order of frequency value to generate broadband impedance spectrum analysis results. During the arrangement process, impedance spectrum data entries with the same frequency value are merged, and abnormal entries with impedance amplitude fluctuations exceeding a preset range are eliminated.

[0132] In this step, the impedance spectrum data entry refers to a structured data unit including a frequency value, a phase difference, and an impedance amplitude, and is used to construct an impedance spectrum.

[0133] In an embodiment of the present invention, all impedance spectrum data entries are arranged in ascending order of frequency value to generate a broadband impedance spectrum analysis result. During the arrangement process, if there are entries with the same frequency value (such as multiple measurements of the same frequency point), they are merged into a single entry, and the average value of their impedance amplitudes is taken. At the same time, abnormal entries with impedance amplitude fluctuations exceeding a preset range (such as impedance changes of more than 20% between adjacent frequency points) are eliminated. Finally, the output broadband impedance spectrum analysis result is an impedance characteristic curve arranged in order by frequency, which is used to reflect the impedance response of the grounding grid at different frequencies.

[0134] The embodiment of the present invention effectively suppresses the impact of noise on impedance calculation through waveform distortion rate screening and windowing processing. At the same time, it combines the temperature anomaly trigger mechanism and broadband impedance spectrum to realize the correlation analysis between electrical parameters and thermal characteristics. In addition, the embodiment only initiates impedance analysis when there is a temperature rise anomaly, reducing computing resource consumption and improving dynamic monitoring efficiency. Finally, through the elimination of abnormal impedance spectrum items and the frequency response curve, local corrosion or fracture faults in the grounding grid are accurately identified.

[0135] The present invention provides a specific embodiment, step 203, performing a windowed Fourier transform on each time domain data segment in the optimized voltage and current time domain waveform data to obtain a voltage spectrum and a current spectrum corresponding to each time domain data segment, specifically comprising the following steps:

[0136] Step 231: multiplying the voltage waveform data and the current waveform data in each time domain data segment in the optimized voltage and current time domain waveform data by a preset window function point by point to generate windowed voltage waveform segments and current waveform segments.

[0137] In this step, the window function refers to a time-domain weighted function used to reduce spectrum leakage, including Hanning window, Hamming window, etc., whose amplitude gradually decays to zero at both ends of the time domain, and is used to suppress the frequency domain distortion caused by signal truncation; point-by-point multiplication refers to multiplying each point of the window function with the corresponding point of the voltage and current time-domain waveform data to generate a windowed time-domain signal; the windowed voltage waveform segment and current waveform segment refer to the time-domain signal segment after weighted processing by the window function, with smooth start and end characteristics.

[0138] In an embodiment of the present invention, each time-domain data segment (e.g., a voltage waveform data segment and a current waveform data segment of 1 second in length) in the optimized voltage and current time-domain waveform data is point-by-point multiplied by a preset window function. Specifically, the length of the window function matches the number of sampling points in the time-domain data segment. The voltage value of each data point (e.g., the kth sampling point) is multiplied by the value at the corresponding position of the window function to generate a windowed voltage waveform segment. The current waveform data segment is processed in the same manner to generate a windowed current waveform segment.

[0139] Step 232: Determine a discrete frequency point set according to the duration and sampling interval of the time domain data segment.

[0140] In this step, the discrete frequency point set refers to a set of discrete frequency analysis points calculated by the time domain data segment duration and the sampling interval, covering frequencies from 0 Hz to integer multiples of the Nyquist frequency.

[0141] In an embodiment of the present invention, the frequency resolution (e.g., 1 Hz) is determined based on the duration of the time domain data segment (e.g., 1 second) and the sampling interval (e.g., 0.001 second, corresponding to a sampling rate of 1 kHz) using the formula fres=1 / T, where T is the duration of the time domain data segment. The set of discrete frequency points is determined by the frequency resolution and covers all integer multiple frequency points (e.g., 0 Hz, 1 Hz, 2 Hz, ..., 500 Hz) from 0 Hz to the Nyquist frequency (i.e., half the sampling rate, e.g., 500 Hz).

[0142] Step 233: Based on the discrete frequency point set, discrete spectrum conversion is performed on the windowed voltage waveform segment and current waveform segment respectively to obtain a voltage spectrum sequence and a current spectrum sequence.

[0143] In this step, discrete spectrum conversion refers to the process of converting the time domain signal into a frequency domain complex spectrum using algorithms such as fast Fourier transform, where each frequency point corresponds to a real part and an imaginary part; the voltage spectrum sequence and the current spectrum sequence refer to sequences composed of complex spectrum values ​​at discrete frequency points, reflecting the amplitude and phase characteristics of the signal at different frequencies.

[0144] In an embodiment of the present invention, based on a set of discrete frequency points, discrete spectrum conversion is performed on the windowed voltage waveform segment and current waveform segment respectively, that is, the fast Fourier transform algorithm is used to convert the time domain signal into a frequency domain signal to obtain a voltage spectrum sequence and a current spectrum sequence. Each spectrum sequence contains complex spectrum values ​​of multiple discrete frequency points, where each complex number is composed of a real part (in-phase component) and an imaginary part (orthogonal component). The complex number of the 50 Hz frequency point in the voltage spectrum sequence is expressed as V(50)=Vreal+jVimaginary.

[0145] Step 234: extracting the voltage real part value and the first imaginary part value at each discrete frequency point from the voltage spectrum sequence to calculate the effective value of the voltage at each discrete frequency point.

[0146] In this step, the real part value of the voltage and the first imaginary part value refer to the in-phase component (real part) and the quadrature component (imaginary part) at a certain frequency point in the voltage spectrum, which are used to calculate the effective value and phase angle.

[0147] In an embodiment of the present invention, the real part value of the voltage (such as Vreal) and the first imaginary part value (such as Vimaginary) at each discrete frequency point are extracted from the voltage spectrum sequence, and the effective value of the voltage is calculated using a formula. That is, the square root of the square of the real part value of the voltage and the square of the first imaginary part value are added together, and the square root is then multiplied by a normalization coefficient (such as 1 / 2). That is, through frequency domain parameter conversion, the effective value reflecting the energy of the voltage signal is obtained.

[0148] Step 235: extracting the current real part value and the second imaginary part value corresponding to the discrete frequency point from the current spectrum sequence to calculate the effective value of the current at each discrete frequency point.

[0149] In this step, the real part value of the current and the second imaginary part value refer to the in-phase component and the orthogonal component of the corresponding frequency point in the current spectrum, and are extracted synchronously with the voltage spectrum parameters.

[0150] In an embodiment of the present invention, the real part value of the current (such as Ireal) and the second imaginary part value (such as Iimaginary) corresponding to the discrete frequency point are extracted from the current spectrum sequence, and the effective value of the current is calculated using a formula, that is, the square of the real part value of the current and the square of the second imaginary part value are added, the square root is taken, and the sum is multiplied by a normalization coefficient.

[0151] Step 236 : Calculate the voltage-current phase difference at each discrete frequency point based on the voltage real part value, the current real part value, the voltage imaginary part value, and the current imaginary part value at each discrete frequency point.

[0152] In this step, the calculation operation refers to a mathematical process of calculating the phase difference through the real and imaginary values ​​of the voltage and current, which includes using the inverse tangent function to calculate the voltage phase angle and the current phase angle, and subtracting the voltage phase angle from the current phase angle to obtain the voltage-current phase difference.

[0153] In an embodiment of the present invention, the voltage-current phase difference is calculated based on the real value of the voltage, the real value of the current, the imaginary value of the voltage (i.e., the first imaginary value), and the imaginary value of the current (i.e., the second imaginary value) at each discrete frequency point, where the voltage phase angle θV=arctan(Vimaginary / Vreal), the current phase angle θI=arctan(Iimaginary / Ireal), and the phase difference Δθ=θV−θI. That is, the phase relationship between the voltage and current signals is accurately quantified through the inverse tangent function and the difference operation.

[0154] Step 237: Bind the voltage RMS value, current RMS value, and voltage-current phase difference of each discrete frequency point with the corresponding frequency value to obtain multiple spectrum entries, sort the multiple spectrum entries, and generate the voltage spectrum and current spectrum corresponding to each time domain data segment.

[0155] In this step, the binding operation refers to the operation of associating the frequency value, voltage RMS value, current RMS value, and phase difference into a data record to form a structured spectrum entry; the spectrum entry refers to the data unit containing the voltage and current parameters at a single frequency point, which is used to construct a complete spectrum analysis result; the sorting operation refers to arranging the spectrum entries in order from small to large frequency value to generate an ordered voltage spectrum and current spectrum.

[0156] In an embodiment of the present invention, the voltage RMS value, current RMS value, and voltage-current phase difference at each discrete frequency point are associated with the corresponding frequency value (e.g., 50 Hz) through a binding operation to form a structured data unit, namely, a spectrum entry. Each spectrum entry contains four fields: frequency value, voltage RMS value, current RMS value, and phase difference. Finally, all spectrum entries are sorted from small to large according to frequency value to generate the voltage spectrum and current spectrum corresponding to each time domain data segment.

[0157] The embodiments of the present invention suppress spectrum leakage through a window function, reduce the interference of noise on the phase difference calculation, and achieve the technical effect of improving anti-interference capability; based on the precise extraction of real and imaginary parts, high-precision calculation of the effective values ​​of voltage and current and the phase difference is ensured to optimize the calculation accuracy; through the binding and sorting of spectrum entries, spectrum results in a unified format are generated to facilitate subsequent fault diagnosis and comparative analysis for standardized data output; based on the complete coverage of the discrete frequency point set, the impedance characteristics of the grounding grid at different frequencies are fully reflected to achieve effective coverage of broadband response.

[0158] The present invention provides a specific embodiment, step 104, extracting the temperature rise rate extreme value from the spatial correlation grid, extracting the phase offset extreme value from the broadband impedance spectrum analysis result, combining the temperature rise rate extreme value and the phase offset extreme value to generate a temperature rise phase offset coupling relationship matrix, specifically comprising the following steps:

[0159] Step 401: extracting the temperature rise rate extreme value of each temperature measurement node within a preset time window from the spatial correlation grid.

[0160] In this step, the extreme value of the temperature rise rate refers to the maximum value of the temperature rise rate of the temperature measurement node within the preset time window, which is calculated by dividing the temperature change by the time interval and reflects the abnormal heating intensity of the local conductor.

[0161] In an embodiment of the present invention, the temperature change data of each temperature measurement node within a preset time window (for example, 10 minutes) is obtained from the spatial correlation grid, and the temperature rise rate curve is obtained by calculating the first-order derivative of the temperature with time, and the maximum point (for example, the local peak value) in the curve is extracted as the extreme value of the temperature rise rate. That is, a sliding window difference calculation is performed on the temperature series of each temperature measurement node, and the formula is ΔT / Δt (temperature change divided by time interval), and the extreme points that exceed the preset threshold (for example, 5°C / min) are screened out.

[0162] Step 402: extracting the phase offset extreme value corresponding to each impedance measurement point from the broadband impedance spectrum analysis result.

[0163] In this step, the phase offset extreme value corresponding to the impedance measurement point refers to the maximum or minimum value of the voltage and current phase difference at a certain impedance measurement point at a specific frequency in the broadband impedance spectrum analysis, which is used to characterize the degree of abnormal offset of the conductor impedance characteristics.

[0164] In an embodiment of the present invention, the phase offset data corresponding to each impedance measurement point (such as the two ends of the grounding grid segmented conductor) is extracted from the broadband impedance spectrum analysis results. By traversing the phase difference records of all discrete frequency points, the maximum and minimum phase offset values ​​are screened out (for example, the phase difference reaches an extreme value of ±15° at a frequency of 50 Hz).

[0165] Step 403: according to the binding relationship between the conductor segment units and the temperature measurement nodes and impedance measurement points in the spatial correlation grid, the temperature rise rate extreme value and the phase offset extreme value corresponding to each conductor segment unit are associated to generate a coupling parameter pair.

[0166] In this step, the binding relationship refers to the pre-defined spatial association rules between the conductor segment unit and the temperature measurement nodes and impedance measurement points. For example, a conductor segment unit is bound to the temperature measurement nodes on its left and right sides and its own impedance measurement point. The association operation refers to the operation of combining the temperature rise rate extreme values ​​and phase offset extreme values ​​corresponding to the same conductor segment unit into a data pair, which is used to establish a joint analysis unit for thermal-electric parameters. The coupling parameter pair refers to the data pair composed of the temperature rise rate extreme values ​​and the phase offset extreme values, such as (12℃ / min, -10°), which is used to comprehensively reflect the abnormal thermoelectric state of the conductor.

[0167] In an embodiment of the present invention, based on the binding relationship between conductor segment units, temperature measurement nodes, and impedance measurement points predefined in a spatial association grid (for example, each conductor segment unit is associated with two temperature measurement nodes and one impedance measurement point), the temperature rise rate extreme value (e.g., 12°C / min) and the phase offset extreme value (e.g., -10°) corresponding to the conductor segment unit are associated to generate a coupling parameter pair. Each coupling parameter pair contains two fields, namely, the temperature rise rate extreme value (unit: °C / min) and the phase offset extreme value (unit: °C).

[0168] Step 404: Based on the conductor topology of the grounding grid, the coupling parameter pairs corresponding to each conductor segment unit are mapped to rows and columns of a preset matrix to generate a temperature rise phase shift coupling relationship matrix.

[0169] In this step, the mapping operation refers to the process of allocating coupling parameter pairs to matrix rows and columns according to the conductor topology, for example, mapping them to matrix elements according to level and orientation to form a spatialized data analysis structure.

[0170] In an embodiment of the present invention, the coupling parameter pairs corresponding to each conductor segment unit are mapped to the rows and columns of a preset matrix through the row index, column index, and matrix element value of the conductor topology structure of the grounding grid to generate a temperature rise phase offset coupling relationship matrix. If the matrix shows that the position parameters of the conductor segment unit are abnormal, the column index branch conductor is determined to have a capacitive overheating fault caused by insulation degradation in combination with topological analysis.

[0171] The embodiments of the present invention improve the accuracy of fault type identification (such as overheating and corrosion) through coupled analysis of temperature rise rate and phase offset, and realize multi-parameter fusion diagnosis. Matrix mapping based on conductor topology intuitively displays the spatial distribution of abnormal areas, supports rapid fault point location, and enhances spatial correlation. By extracting extreme values ​​within the time window, transient abnormal signals are captured to avoid missed detection and improve dynamic monitoring capabilities. By mapping complex thermoelectric parameters into a matrix structure, the analysis complexity under large data volumes is simplified, thereby performing data dimensionality reduction processing.

[0172] The present invention provides a specific embodiment, step 105, generating a real-time monitoring result of the power frequency resistance of the grounding grid according to the power frequency impedance correction value of the temperature rise phase shift coupling relationship matrix, specifically comprising the following steps:

[0173] Step 501: Filter out a plurality of target matrix elements from the temperature rise phase offset coupling relationship matrix, and use the target matrix elements as key correction factors. The target matrix elements are matrix elements whose temperature rise rate extreme value and phase offset extreme value both exceed preset thresholds.

[0174] In this step, the target matrix element refers to the matrix unit in the temperature rise phase shift coupling relationship matrix that simultaneously satisfies the temperature rise rate extreme value and the phase shift extreme value exceeding the preset threshold, which is used to identify the abnormally sensitive area of ​​the conductor; the key correction factor refers to the coupling coefficient value extracted from the target matrix element, which reflects the comprehensive influence of local temperature rise and phase shift on the power frequency impedance.

[0175] In an embodiment of the present invention, target matrix elements are screened from the temperature-rise phase-shift coupling relationship matrix, specifically matrix elements that simultaneously satisfy the conditions that the extreme value of the temperature-rise rate (ΔT / Δt) exceeds a preset temperature-rise threshold (e.g., 0.5°C / s) and the extreme value of the phase shift (Δθ) exceeds a preset phase threshold (e.g., 20°). A threshold determination algorithm is used to traverse all elements of the matrix, and elements that meet the conditions are marked as key correction factors, which are used to characterize the area where local conductor anomalies significantly affect the power frequency impedance.

[0176] Step 502: Calculate the weight coefficient of each key correction factor according to the proportional relationship between the temperature rise rate extreme value and the phase offset extreme value corresponding to each key correction factor.

[0177] In this step, the calculation operation refers to the data processing process of determining the contribution weight of each key correction factor through the proportional relationship between the extreme value of the temperature rise rate and the extreme value of the phase offset and normalization processing; the weight coefficient refers to the proportional parameter that quantifies the degree of influence of the key correction factor on the overall correction value, the sum of which is 1, and is used for weighted superposition calculation.

[0178] In an embodiment of the present invention, a weight coefficient is calculated based on the proportional relationship between the temperature rise rate extreme value and the phase offset extreme value corresponding to the key correction factor, namely: (temperature rise rate extreme value / temperature rise threshold) × (phase offset extreme value / phase threshold). The calculated results of all key correction factors are then normalized (each weight coefficient is divided by the total) so that the total of the weight coefficients is 1. This process is implemented through a numerical normalization algorithm to ensure that the contribution of the correction factors in different regions is distributed proportionally.

[0179] Step 503: Based on the weight coefficients, the key correction factors are superimposed to generate a power frequency impedance region correction value.

[0180] In this step, the superposition operation refers to a calculation method of multiplying each key correction factor by its weight coefficient and then accumulating them to generate a comprehensive correction value to eliminate local interference; the power frequency impedance area correction value refers to the impedance compensation amount obtained by weighted calculation of the key correction factors, which is used to correct errors in traditional power frequency measurement values.

[0181] In an embodiment of the present invention, a superposition operation is used to multiply each key correction factor by its weight coefficient and then accumulate them to generate a power frequency impedance regional correction value. For example, if the three key correction factors are 0.6, 0.8, and 1.0, respectively, and the weight coefficients are 0.2, 0.3, and 0.5, respectively, then the regional correction value = 0.6×0.2+0.8×0.3+1.0×0.5=0.12+0.24+0.5=0.86, where the regional correction value is used to dynamically correct the power frequency impedance measurement value.

[0182] Step 504: Mapping the power frequency impedance regional correction value to the corresponding conductor segment unit in the spatial correlation grid to generate a real-time monitoring result of the power frequency resistance of the grounding grid.

[0183] In this step, the mapping operation refers to the data matching process of dynamically associating the correction value according to the distribution of the conductor segment units of the spatial correlation grid to ensure that the correction value acts on the corresponding physical location; the real-time monitoring result of the power frequency resistance refers to the 50Hz equivalent resistance value corrected by the regional correction value, which dynamically reflects the conductive state of the grounding grid as a whole and in each segment.

[0184] In an embodiment of the present invention, the power frequency impedance area correction value is associated with the corresponding conductor segment unit in the spatial association grid through a mapping operation, that is, according to the position index of the matrix element to which the correction value belongs, the conductor segment unit number in the spatial association grid is matched, and the correction value is multiplied by the proportion of the unit conductor length (unit conductor length / total length of the grounding grid). Finally, the contribution values ​​of all units are accumulated to obtain the overall power frequency resistance value, so as to realize the dynamic output of real-time monitoring results.

[0185] The embodiment of the present invention focuses on local abnormal areas by screening key correction factors and enhances the physical rationality of the correction logic by combining weight coefficient distribution. The superposition calculation and spatial mapping operations realize dynamic compensation of abnormal influences, breaking through the overall error accumulation problem caused by local interference in traditional power frequency resistance measurement, and significantly improving the accuracy and anti-interference ability of grounding grid status assessment under complex working conditions.

[0186] Figure 2 The present invention provides a structural diagram of a real-time monitoring system for the power frequency resistance of a 27.5kV cable section grounding network for traction power supply, as shown in FIG. Figure 2 As shown, the system includes:

[0187] An acquisition module 21 is configured to acquire temperature distribution data on the conductor surface of a grounding grid within a 27.5 kV traction power cable section, wherein the grounding grid includes a plurality of temperature measurement nodes arranged at equal intervals within the 27.5 kV traction power cable section;

[0188] a conversion module 22 for collecting voltage and current responses of the grounding grid when a local temperature rise value exceeds a preset reference value, and performing frequency domain conversion on the voltage and current responses to generate a broadband impedance spectrum analysis result, wherein the local temperature rise value is obtained from the temperature distribution data;

[0189] an alignment module 23 for aligning the surface coordinates corresponding to the temperature measurement nodes with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis results according to the conductor topology of the grounding grid, thereby generating a spatial correlation grid;

[0190] An extraction module 24 is configured to extract temperature rise rate extreme values ​​from the spatial correlation grid, extract phase offset extreme values ​​from the broadband impedance spectrum analysis results, and generate a temperature rise phase offset coupling relationship matrix by combining the temperature rise rate extreme values ​​and the phase offset extreme values;

[0191] The generating module 25 is configured to generate a real-time monitoring result of the power frequency resistance of the grounding grid according to the power frequency impedance correction value of the temperature rise phase shift coupling relationship matrix.

[0192] Figure 2 The real-time monitoring system for the power frequency resistance of the 27.5kV cable section grounding network for traction power supply can be used to Figure 1 The implementation principles and technical effects of the method for real-time monitoring of the power-frequency resistance of a 27.5kV traction power supply cable-connected grounding grid described in the illustrated embodiment are not further elaborated. The specific manner in which each module and unit performs operations in the system for real-time monitoring of the power-frequency resistance of a 27.5kV traction power supply cable-connected grounding grid in the aforementioned embodiment has been described in detail in the related embodiments and will not be further elaborated here.

[0193] In one possible design, Figure 2 The embodiment shown is a real-time monitoring system for the power frequency resistance of the traction power supply 27.5kV cable section grounding network, which can be implemented as a computing device, such as Figure 3 As shown, the computing device may include a storage component 31 and a processing component 32;

[0194] The storage component 31 stores one or more computer instructions, wherein the one or more computer instructions are called and executed by the processing component 32 .

[0195] The processing component 32 is configured to: obtain temperature distribution data on the conductor surface of a grounding grid in a 27.5 kV traction power supply cable section, the grounding grid including a plurality of temperature measurement nodes equidistantly spaced along the 27.5 kV traction power supply cable section; collect voltage and current responses of the grounding grid when a local temperature rise value exceeds a preset reference value, perform frequency domain conversion on the voltage and current responses to generate a broadband impedance spectrum analysis result, wherein the local temperature rise value is obtained from the temperature distribution data; align surface coordinates corresponding to the temperature measurement nodes with underground coordinates corresponding to impedance measurement points in the broadband impedance spectrum analysis result based on the conductor topology of the grounding grid to generate a spatial correlation grid; extract temperature rise rate extremes from the spatial correlation grid, extract phase offset extremes from the broadband impedance spectrum analysis result, and combine the temperature rise rate extremes and the phase offset extremes to generate a temperature rise phase offset coupling relationship matrix; and generate real-time monitoring results of the power frequency resistance of the grounding grid based on the power frequency impedance correction value of the temperature rise phase offset coupling relationship matrix.

[0196] The processing component 32 may include one or more processors to execute computer instructions to complete all or part of the steps in the above method. Of course, the processing component may also be implemented as one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the above method.

[0197] The storage component 31 is configured to store various types of data to support operations at the terminal. The storage component can be implemented by any type of volatile or non-volatile memory device, or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk, or optical disk.

[0198] Of course, a computing device may also include other components, such as input / output interfaces, display components, communication components, etc.

[0199] The input / output interface provides an interface between the processing component and the peripheral interface module, which can be an output device, an input device, etc.

[0200] The communication component is configured to facilitate, among other things, wired or wireless communications between the computing device and other devices.

[0201] Among them, the computing device can be a physical device or an elastic computing host provided by a cloud computing platform, etc. In this case, the computing device can refer to a cloud server, and the above-mentioned processing components, storage components, etc. can be basic server resources rented or purchased from the cloud computing platform.

[0202] The embodiment of the present invention further provides a computer storage medium storing a computer program, which can achieve the above-mentioned Figure 1 The embodiment shown is a method for real-time monitoring of the power frequency resistance of a grounding network in a 27.5 kV cable section of a traction power supply.

[0203] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0204] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0205] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0206] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for real-time monitoring of the power frequency resistance of a 27.5kV cable section grounding grid for traction power supply, characterized in that: include: Acquire temperature distribution data on the conductor surface of a grounding grid within a 27.5 kV traction power cable section, wherein the grounding grid includes a plurality of temperature measurement nodes arranged at equal intervals within the 27.5 kV traction power cable section; collecting voltage and current responses of the grounding grid when a local temperature rise value exceeds a preset reference value, performing frequency domain conversion on the voltage and current responses to generate a broadband impedance spectrum analysis result, wherein the local temperature rise value is obtained from the temperature distribution data; According to the conductor topology of the grounding grid, the surface coordinates corresponding to the temperature measurement nodes are aligned with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis results to generate a spatial correlation grid; Extracting the temperature rise rate extreme value from the spatial correlation grid, extracting the phase offset extreme value from the broadband impedance spectrum analysis result, and combining the temperature rise rate extreme value and the phase offset extreme value to generate a temperature rise phase offset coupling relationship matrix; A real-time monitoring result of the power frequency resistance of the grounding grid is generated according to the power frequency impedance correction value of the temperature rise phase shift coupling relationship matrix.

2. The method according to claim 1, characterized in that According to the conductor topology of the grounding grid, the surface coordinates corresponding to the temperature measurement nodes are aligned with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis results to generate a spatial correlation grid, including: According to the conductor topology of the grounding grid, the length of the conductor segment, the location of the branch connection point, and the vertical coordinate of the conductor buried depth corresponding to the location of the branch connection point are obtained; Determining the actual installation position of the temperature measurement node according to the conductor segment and the position of the branch connection point; Filtering the frequency interval in which the impedance amplitude in the conductor segment decreases by more than a preset decrease value from the broadband impedance spectrum analysis result, and determining the coordinate point of the position with the maximum current density in the conductor segment as the impedance measurement point based on the current distribution characteristics corresponding to the frequency interval; The surface coordinates corresponding to the actual installation position of the temperature measurement node, the vertical coordinates of the conductor burial depth, and the underground coordinates corresponding to the impedance measurement point are bound to generate a spatial correlation grid.

3. The method according to claim 2, characterized in that Binding the surface coordinates corresponding to the actual installation position of the temperature measurement node, the vertical coordinates of the conductor burial depth, and the underground coordinates corresponding to the impedance measurement point to generate a spatial correlation grid, including: Based on the length of the conductor segment and the location of the branch connection point, the grounding grid is divided into a plurality of conductor segment units, wherein each conductor segment unit includes a temperature measurement node and an impedance measurement point; Superimposing the surface coordinates corresponding to the actual installation position of the temperature measurement node in each conductor segment unit with the vertical coordinates of the conductor burial depth to generate the three-dimensional monitoring coordinates corresponding to the temperature measurement node in each conductor segment unit; According to the underground coordinates corresponding to the impedance measurement points in each conductor segment unit, the underground coordinates corresponding to the impedance measurement points in each conductor segment unit are spatially bound with the corresponding three-dimensional monitoring coordinates to generate a bound coordinate pair for each conductor segment unit; Aggregating the bound coordinate pairs of multiple conductor segment units adjacent to the branch connection point with the vertical coordinate of the conductor burial depth to generate a branch topology node; The binding coordinate pairs and the branch topology nodes are mapped to generate a spatial association grid.

4. The method according to claim 1, wherein Collecting voltage and current responses of the grounding grid when a local temperature rise value exceeds a preset reference value, performing frequency domain conversion on the voltage and current responses to generate a broadband impedance spectrum analysis result, wherein the local temperature rise value is obtained from the temperature distribution data, includes: When the temperature rise value of at least one temperature measurement node in the temperature distribution data exceeds a preset reference value, it is determined that there is a local temperature rise abnormality in the grounding grid, and the voltage and current time domain waveform data at both ends of the grounding grid under the excitation signal are collected; Dividing the voltage and current time domain waveform data into a plurality of time domain data segments according to a preset time period, and removing the time domain data segments whose waveform distortion rate exceeds a preset distortion threshold, so as to generate optimized voltage and current time domain waveform data; Performing a windowed Fourier transform on each time domain data segment in the optimized voltage and current time domain waveform data to obtain a voltage spectrum and a current spectrum corresponding to each time domain data segment; Extracting the voltage effective value of each discrete frequency point from the voltage spectrum, and extracting the current effective value corresponding to the discrete frequency point from the current spectrum, so as to calculate the voltage-current phase difference and impedance amplitude corresponding to each discrete frequency point; Associating the voltage and current phase difference, impedance amplitude and frequency value corresponding to each discrete frequency point into an impedance spectrum data entry; All impedance spectrum data entries are arranged in ascending order of frequency value to generate broadband impedance spectrum analysis results. During the arrangement process, impedance spectrum data entries with the same frequency value are merged, and abnormal entries with impedance amplitude fluctuations exceeding the preset range are eliminated.

5. The method according to claim 4, characterized in that Performing a windowed Fourier transform on each time domain data segment in the optimized voltage and current time domain waveform data to obtain a voltage spectrum and a current spectrum corresponding to each time domain data segment, including: Multiplying the voltage waveform data and the current waveform data in each time domain data segment of the optimized voltage and current time domain waveform data by a preset window function point by point to generate windowed voltage waveform segments and current waveform segments; Determining a discrete frequency point set according to the duration and sampling interval of the time domain data segment; Based on the discrete frequency point set, discrete spectrum conversion is performed on the windowed voltage waveform segment and current waveform segment to obtain a voltage spectrum sequence and a current spectrum sequence; Extracting the voltage real part value and the first imaginary part value of each discrete frequency point from the voltage spectrum sequence to calculate the effective value of the voltage at each discrete frequency point; Extracting the current real part value and the second imaginary part value corresponding to the discrete frequency point from the current spectrum sequence to calculate the effective value of the current at each discrete frequency point; Calculate the voltage and current phase difference at each discrete frequency point based on the voltage real part value, current real part value, voltage imaginary part value and current imaginary part value at each discrete frequency point; The voltage RMS value, current RMS value, and voltage-current phase difference of each discrete frequency point are bound to the corresponding frequency value to obtain multiple spectrum entries. The multiple spectrum entries are sorted to generate the voltage spectrum and current spectrum corresponding to each time domain data segment.

6. The method according to claim 1, characterized in that Extracting the temperature rise rate extreme value from the spatial correlation grid, extracting the phase offset extreme value from the broadband impedance spectrum analysis result, and combining the temperature rise rate extreme value and the phase offset extreme value to generate a temperature rise phase offset coupling relationship matrix, including: Extracting the temperature rise rate extreme value of each temperature measurement node within a preset time window from the spatial correlation grid; Extracting the phase offset extreme value corresponding to each impedance measurement point from the broadband impedance spectrum analysis result; According to the binding relationship between the conductor segment units and the temperature measurement nodes and the impedance measurement points in the spatial correlation grid, the temperature rise rate extreme value and the phase offset extreme value corresponding to each conductor segment unit are associated to generate a coupling parameter pair; Based on the conductor topology of the grounding grid, the coupling parameter pairs corresponding to each conductor segment unit are mapped to the rows and columns of a preset matrix to generate a temperature rise phase shift coupling relationship matrix.

7. The method according to claim 1, characterized in that Generating a real-time monitoring result of the power frequency resistance of the grounding grid according to the power frequency impedance correction value of the temperature rise phase shift coupling relationship matrix, including: Screening out a plurality of target matrix elements from the temperature rise phase offset coupling relationship matrix, and using the target matrix elements as key correction factors, wherein the target matrix elements are matrix elements whose extreme values ​​of temperature rise rate and phase offset both exceed preset thresholds; Calculate the weight coefficient of each key correction factor based on the proportional relationship between the temperature rise rate extreme value and the phase offset extreme value corresponding to each key correction factor; According to the weight coefficient, each key correction factor is superimposed to generate a power frequency impedance region correction value; The power frequency impedance region correction value is mapped to the corresponding conductor segment unit in the spatial correlation grid to generate a real-time monitoring result of the power frequency resistance of the grounding grid.

8. A real-time monitoring system for the power frequency resistance of the grounding network in a 27.5kV cable section of a traction power supply, characterized by: include: An acquisition module, configured to acquire temperature distribution data of a conductor surface of a grounding grid within a 27.5 kV traction power supply cable section, the grounding grid comprising a plurality of temperature measurement nodes equally spaced along the 27.5 kV traction power supply cable section; a conversion module, configured to collect voltage and current responses of the grounding grid when a local temperature rise value exceeds a preset reference value, and perform frequency domain conversion on the voltage and current responses to generate a broadband impedance spectrum analysis result, wherein the local temperature rise value is obtained from the temperature distribution data; an alignment module, configured to align the surface coordinates corresponding to the temperature measurement nodes with the underground coordinates corresponding to the impedance measurement points in the broadband impedance spectrum analysis results according to the conductor topology of the grounding grid, thereby generating a spatial correlation grid; an extraction module, configured to extract temperature rise rate extremes from the spatial correlation grid, extract phase offset extremes from the broadband impedance spectrum analysis results, and generate a temperature rise phase offset coupling relationship matrix by combining the temperature rise rate extremes and the phase offset extremes; A generating module is used to generate a real-time monitoring result of the power frequency resistance of the grounding grid according to the power frequency impedance correction value of the temperature rise phase shift coupling relationship matrix.

9. A computing device, characterized in that It includes a processing component and a storage component; the storage component stores one or more computer instructions; the one or more computer instructions are used to be called and executed by the processing component to implement a real-time monitoring method for the power frequency resistance of a traction power supply 27.5kV cable section grounding network as described in any one of claims 1 to 7.

10. A computer storage medium, characterized in that A computer program is stored, and when the computer program is executed by a computer, a real-time monitoring method for the power frequency resistance of a traction power supply 27.5kV cable section grounding network is implemented as described in any one of claims 1 to 7.

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