Method for detecting impurities and defects in the wrapping tape of 10kV cable terminals

Abstract

The method for detecting impurity defects in the wrapping tape of a 10kV cable terminal provided in this application includes: transmitting a high-frequency microwave signal to the wrapping tape area of ​​the 10kV cable terminal to be evaluated, and acquiring the reflection coefficient curve of the reflected wave; the frequency band of the high-frequency microwave signal is 22GHz~30GHz; selecting a preset number of minimum values ​​from the reflection coefficient curve as reflection characteristic values ​​to be evaluated, and selecting a corresponding defect-free reflection characteristic value based on the frequency of each reflection characteristic value to be evaluated; calculating the absolute value of the difference between each reflection characteristic value to be evaluated and each defect-free reflection characteristic value, and calculating a defect feature offset factor based on the absolute value of the difference; calculating the wrapping tape impurity defect characterization parameter based on each reflection characteristic value to be evaluated and the defect feature offset factor, and evaluating the defects in the wrapping tape area of ​​the cable terminal to be evaluated using the wrapping tape impurity defect characterization parameter. This achieves efficient identification of impurity defects in the wrapping tape area of ​​the cable terminal.

Description

Technical Field

[0001] This application relates to the field of cable joint inspection and evaluation technology, and in particular to a method for detecting impurity defects in the wrapping tape of a 10kV cable terminal. Background Technology

[0002] With the continuous expansion of urban construction and electricity consumption, society's demand for electricity is constantly increasing, while the requirements for power quality and supply reliability are also rising. Cross-linked polyethylene (XLPE) cables, due to their excellent mechanical and electrical properties, as well as their advantages of flexible laying, convenient installation, and high safety, have been widely used in the power transmission links of urban power grids, rail transit, and other power systems. As a key component in cable lines, cable terminals not only play a role in regulating the electric field distribution at the end of the cable insulation shielding layer, ensuring the normal operation of the cable system, but also undertake the task of connecting and fixing the cable to electrical equipment, thereby maintaining the stability of power transmission.

[0003] However, during the actual installation of cable terminals, due to inadequate construction process control or insufficient cleanliness of the installation environment, metal particles, dust, and other foreign matter can easily remain in the critical interface area between the sealant and the semi-conductive tape. These impurities may have high dielectric constants or conductivity, disrupting the uniformity of the local electric field distribution and affecting the long-term stability of the insulation structure. With increasing operating time, impurities trapped in the wrapping tape may cause electric field distortion and form persistent discharge channels in localized areas. Partial discharge gradually degrades the insulation material, potentially leading to breakdown faults, power outages, and affecting the safe operation of the power system.

[0004] Currently, research on the detection of impurities and defects in the wrapping tape of 10kV cables is still relatively limited, and mature and efficient application methods are lacking. Therefore, there is an urgent need for a reliable defect detection method that can assist maintenance personnel in promptly assessing the service status of cables after installation. This is of great significance for ensuring the stable operation of cable systems and improving equipment utilization efficiency. Summary of the Invention

[0005] The purpose of this application is to at least solve one of the aforementioned technical defects, particularly the technical defect in the prior art of how to reliably detect impurities and defects in the wrapping tape of 10kV cables.

[0006] In a first aspect, this application provides a method for detecting impurity defects in the wrapping tape of a 10kV cable termination, the method comprising:

[0007] A high-frequency microwave signal was emitted to the wrapping tape of the 10kV cable terminal to be evaluated, and the reflection coefficient curve of the reflected wave was obtained. The frequency band of the high-frequency microwave signal was 22GHz~30GHz.

[0008] A preset number of minimum values ​​are selected from the reflection coefficient curve as the reflection characteristic values ​​to be evaluated, and the corresponding defect-free reflection characteristic value is selected according to the frequency of each reflection characteristic value to be evaluated.

[0009] Based on each reflection feature value to be evaluated and each defect-free reflection feature value, calculate the absolute value of the difference, and based on the absolute value of the difference, calculate the defect feature offset factor;

[0010] Based on the reflection characteristic values ​​and defect characteristic offset factors to be evaluated, the characterization parameters of the wrapping tape impurities are calculated, and the defects of the wrapping tape part of the cable terminal to be evaluated are evaluated through the characterization parameters of the wrapping tape impurities.

[0011] In one embodiment, the step of transmitting a high-frequency microwave signal to the wrapping tape portion of a 10kV cable termination to be evaluated includes:

[0012] A vector network analyzer is used to transmit a high-frequency microwave signal to the 10kV cable terminal to be evaluated, so that the high-frequency microwave signal is transmitted through a coaxial cable and a rectangular waveguide and then vertically injected into the wrapping tape of the cable terminal to be evaluated.

[0013] In one embodiment, the step of calculating the absolute value of the difference based on each reflection feature value to be evaluated and each defect-free reflection feature value includes:

[0014] Calculate the absolute value of the difference using the following expression:

[0015]

[0016] in, Indicates the first The absolute value of the difference, Indicates the first The difference between each reflection feature value to be evaluated and its corresponding defect-free reflection feature value Indicates the first One reflection characteristic value to be evaluated, Indicates the first One defect-free reflection characteristic value.

[0017] In one embodiment, the step of calculating the defect feature offset factor based on the absolute value of the difference includes:

[0018] Calculate the defect feature offset factor using the following expression:

[0019]

[0020] in, Indicates the defect feature offset factor. This represents the absolute value of the difference.

[0021] In one embodiment, the step of calculating the characterization parameters of the wrapping tape impurity defects based on each reflection feature value to be evaluated and the defect feature offset factor includes:

[0022] Calculate the characterization parameters of impurity defects in the wrapping tape using the following expression:

[0023]

[0024] in, This indicates the parameters characterizing impurities and defects in the wrapping tape. Indicates the defect feature offset factor. Indicates the first One reflection characteristic value to be evaluated.

[0025] In one embodiment, the step of evaluating defects in the wrapping tape portion of the cable terminal to be evaluated, using wrapping tape impurity defect characterization parameters, includes:

[0026] When the defect characterization parameter of the wrapping tape is not greater than the first preset threshold, there are no impurities in the wrapping tape part of the cable terminal to be evaluated.

[0027] When the defect characterization parameter of the wrapping tape impurities is greater than the first preset threshold and not greater than the second preset threshold, the wrapping tape part of the cable terminal to be evaluated contains dust impurities.

[0028] When the defect characterization parameter of the wrapping tape is greater than the second preset threshold, the wrapping tape part of the cable terminal to be evaluated contains metallic impurities.

[0029] In one embodiment, the first preset threshold is 3.817 and the second preset threshold is 5.639.

[0030] Secondly, this application provides a device for detecting impurity defects in the wrapping tape of a 10kV cable termination, the device comprising:

[0031] The reflection coefficient curve acquisition module is used to transmit high-frequency microwave signals to the wrapping tape part of the 10kV cable terminal to be evaluated and acquire the reflection coefficient curve of the reflected wave. The frequency band of the high-frequency microwave signal is 22GHz~30GHz.

[0032] The reflection feature value selection module is used to select a preset number of minimum values ​​from the reflection coefficient curve as reflection feature values ​​to be evaluated, and select the corresponding defect-free reflection feature value according to the frequency of each reflection feature value to be evaluated.

[0033] The defect feature offset factor calculation module is used to calculate the absolute value of the difference based on each reflection feature value to be evaluated and each defect-free reflection feature value, and to calculate the defect feature offset factor based on the absolute value of the difference.

[0034] The wrapping tape impurity defect assessment module is used to calculate the wrapping tape impurity defect characterization parameters based on each reflection characteristic value to be assessed and the defect characteristic offset factor, and to assess the defects of the wrapping tape part of the cable terminal to be assessed through the wrapping tape impurity defect characterization parameters.

[0035] Thirdly, this application provides a storage medium storing computer-readable instructions, which, when executed by one or more processors, cause the one or more processors to perform the steps of any of the 10kV cable terminal wrapping tape impurity defect detection methods described in the above embodiments.

[0036] Fourthly, this application provides a computer device, including: one or more processors, and a memory;

[0037] The memory stores computer-readable instructions, which, when executed by one or more processors, perform the steps of any of the 10kV cable terminal wrapping tape impurity defect detection methods described in the above embodiments.

[0038] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:

[0039] The 10kV cable terminal wrapping tape impurity defect detection method provided in this application can efficiently identify impurity defects in the cable terminal wrapping tape area without damaging the cable structure, demonstrating significant technical advantages. First, by emitting high-frequency microwave signals in the 22GHz~30GHz band to the cable terminal wrapping tape area and acquiring the reflection coefficient curve, non-contact detection of the electromagnetic response characteristics inside the wrapping structure can be achieved, avoiding the risk of secondary damage caused by disassembling the cable for inspection and improving the safety and ease of operation of the detection process. Second, by selecting a preset number of minimum values ​​from the reflection coefficient curve as reflection characteristic values, combined with the corresponding standard characteristic values ​​under defect-free conditions, the changes in electromagnetic characteristics caused by the presence of impurities in the wrapping tape structure can be accurately captured, improving the sensitivity and accuracy of defect identification. Furthermore, by calculating the defect characteristic offset factor through differential absolute value, the degree of impurity disturbance to the electric field can be quantified, providing a clear numerical indicator basis for the detection process and facilitating the graded assessment of the severity of impurity defects. Finally, by constructing and quantitatively evaluating the characterization parameters of impurity defects in the wrapping tape, we can provide maintenance personnel with an intuitive and reliable basis for defect identification, promptly identify potential hazards, effectively reduce the risk of insulation degradation or breakdown faults caused by impurities, and improve the overall safety and reliability of cable terminal operation, which has important engineering application value. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A schematic flowchart illustrating the method for detecting impurities and defects in the wrapping tape of a 10kV cable terminal provided in this application embodiment;

[0042] Figure 2 This is a schematic diagram of the structure of the 10kV cable terminal wrapping tape impurity defect detection device provided in the embodiments of this application;

[0043] Figure 3 This is a schematic diagram of the internal structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] This application provides a method for detecting impurity defects in the wrapping tape of a 10kV cable termination. The following embodiments illustrate this method using a computer device as an example. It is understood that the computer device can be any device with data processing capabilities, including but not limited to a single server, server cluster, personal laptop, desktop computer, etc. Figure 1 As shown, the method may include the following steps:

[0046] S101: Transmit a high-frequency microwave signal to the wrapping tape section of the 10kV cable terminal to be evaluated, and obtain the reflection coefficient curve of the reflected wave. The frequency band of the high-frequency microwave signal is 22GHz~30GHz.

[0047] The cable termination to be evaluated refers to the cable termination structure in a 10kV cross-linked polyethylene (XLPE) cable system during the evaluation or maintenance testing phase. It includes multiple functional components such as stress cones, wrapping tape, and sealant, used to achieve electrical connection and electric field control between the cable and electrical equipment. The wrapping tape area refers to the area of ​​semiconductor or insulating tape covering the main insulation in the cable termination for further voltage equalization and sealing. This area is commonly found outside the stress cone and is a sensitive location where impurities easily remain and electric field distortion is frequent. High-frequency microwave signals refer to electromagnetic wave signals with frequencies between 22GHz and 30GHz. This frequency band has a short wavelength and limited penetration capability, making it suitable for non-contact, high-resolution testing of the cable surface covering structure. The reflection coefficient curve of the reflected wave refers to the frequency domain response data formed by the reflection of the incident signal by the electromagnetic structure inside the cable wrapping tape under the action of a microwave signal. By collecting this response curve, the electromagnetic characteristics and structural integrity of the tested area can be reflected.

[0048] Specifically, the computer equipment may include a detection terminal with signal control, data acquisition, and processing capabilities, which is connected to a microwave detection device integrating an RF transmitting module and a receiving module. During detection, the port of the microwave detection device can be attached to the outer surface of the wrapping tape of the cable terminal to be evaluated, ensuring close contact between the probe and the cable surface to reduce signal attenuation and interference errors. Based on this, the computer equipment controls the detection device to operate in the frequency range of 22GHz to 30GHz, transmitting high-frequency microwave signals with preset frequency steps point by point, so that the microwave signals are injected radially and vertically into the wrapping tape area.

[0049] Subsequently, the computer equipment receives the signals reflected back from the wrapping tape structure in real time, obtains the complex form of the reflection coefficient value at each frequency point through a network analyzer, and plots the reflection coefficient values ​​corresponding to each frequency point into a complete reflection coefficient curve. This reflection curve can reflect the electromagnetic response characteristics of the target wrapping area and is used for defect feature identification.

[0050] Furthermore, to improve data processing efficiency, after acquiring the reflection coefficient curve, the computer equipment can call the built-in Fourier transform module or noise filtering algorithm to perform denoising and feature enhancement processing on the original curve. By setting the selection criteria for the curve's minimum value, such as the downward envelope truncation or curvature change abrupt change detection, several representative minimum points in the reflection curve can be accurately extracted, providing basic reflection feature data for defect analysis.

[0051] It is understandable that transmitting high-frequency microwave signals in the 22GHz~30GHz frequency band can effectively stimulate the electromagnetic response characteristics of the cable terminal wrapping tape. Due to the short wavelength of signals in this band, it is highly sensitive to changes in microstructure, making it particularly suitable for identifying small defects in the wrapping tape. Acquiring the reflected signal in the frequency domain and constructing a reflection coefficient curve can visually present the influence of impurities on local electromagnetic properties, thereby aiding in the analysis of potential electric field distortion regions. Furthermore, the use of non-contact microwave detection eliminates the need to disassemble the cable structure, greatly improving the safety and adaptability of the detection process. This method not only improves the efficiency of cable terminal evaluation and reduces the risk of human intervention, but also achieves high-precision, highly repeatable acquisition of electromagnetic characteristics, providing a stable and reliable raw data foundation for defect identification and diagnosis, and possesses significant engineering applicability and promotional value.

[0052] S102: Select a preset number of minimum values ​​from the reflection coefficient curve as the reflection characteristic values ​​to be evaluated, and select the corresponding defect-free reflection characteristic value according to the frequency of each reflection characteristic value to be evaluated.

[0053] The preset minimum values ​​refer to several local minimum reflection points automatically identified from the reflection coefficient curve according to a set selection number. These represent characteristic locations where structural changes or impurities may exist. The reflection characteristic value to be evaluated refers to the reflection coefficient value at the frequency point corresponding to the aforementioned minimum values, used to reflect the actual electromagnetic response of the cable terminal under test at that frequency point. The defect-free reflection characteristic value refers to the standard reflection coefficient value measured at the same frequency point by a standard cable terminal known to be free of impurities and defects. This serves as a comparison baseline to identify whether the cable terminal exhibits abnormal reflection behavior.

[0054] Specifically, after acquiring the reflection coefficient curve through the control signal acquisition module, the computer equipment can activate the feature extraction module to perform minimum value identification on the curve. To improve the stability and noise resistance of feature identification, the original reflection coefficient curve can first undergo smoothing filtering, such as using moving average, Savitzky-Golay filtering, or wavelet denoising algorithms, to eliminate high-frequency noise interference and retain the main trend of change.

[0055] After curve preprocessing, the computer equipment identifies the location of local minima on the curve according to the set minimum selection rules, such as points where the first derivative is zero and the second derivative is greater than zero. The number of selections, N, can be set as a parameter input to automatically select the top N smallest reflection coefficient values ​​from all candidate minima as the reflection feature values ​​to be evaluated. Furthermore, to ensure the reasonable distribution of feature points in the frequency domain, frequency spacing constraints or peak difference limits can be added to prevent the selected feature points from being highly concentrated or containing redundant information.

[0056] Furthermore, for each selected reflection characteristic value to be evaluated, the computer device can retrieve a reference reflection dataset of defect-free cable terminals pre-stored in the database and select the defect-free reflection characteristic value corresponding to that frequency point. This database can be established through extensive pre-experimentation and correlated with parameters such as cable type, structure, and wrapping tape material to ensure the compatibility and effectiveness of the matching data.

[0057] It is understandable that by selecting a predetermined number of minimum values ​​from the reflection coefficient curve as the reflection characteristic values ​​to be evaluated, the most sensitive points reflecting structural response anomalies in the curve can be extracted in a concentrated manner. This simplifies data processing while significantly improving the focus and efficiency of defect identification. Furthermore, by obtaining standard reflection characteristic values ​​under defect-free conditions at these characteristic frequency points as a reference, the influence of non-structural factors such as environmental interference and material differences on the comparison results can be minimized, achieving objectivity and specificity in difference comparison. Overall, this method not only improves the automation level of defect location and feature extraction but also enhances the system's ability to distinguish the influence of minute impurities, contributing to high-precision cable terminal quality assessment and defect early warning, and possessing good engineering feasibility and practical application value.

[0058] S103: Calculate the absolute value of the difference based on each reflection feature value to be evaluated and each defect-free reflection feature value, and calculate the defect feature offset factor based on the absolute value of the difference.

[0059] Among them, the absolute difference value refers to the absolute value of the numerical difference between each reflection characteristic value to be evaluated and its corresponding defect-free reflection characteristic value, which is used to quantify the degree of deviation in the reflection response. The defect characteristic deviation factor is a quantitative index reflecting the overall degree of defect deviation obtained by combining the absolute differences of each value, and is used as the core basis for judging the strength of impurity defects in the wrapping tape.

[0060] After matching the reflection feature values ​​to be evaluated with their corresponding defect-free reflection feature values, the computer equipment can call its built-in calculation module to perform differential absolute value calculations on each pair of feature values ​​in sequence. To enhance the overall expressive power of anomalous offsets, the computer equipment can further normalize the above differential absolute value sequence to eliminate the influence of the order of magnitude of the reflection coefficient under different test conditions, for example, by using the maximum value normalization method or the Z-score normalization method to achieve uniform scaling.

[0061] After normalization, the computer equipment can calculate the defect feature offset factor by combining the absolute values ​​of the differences according to the set weight model or average fusion strategy. For example, the arithmetic mean of the absolute values ​​of each difference can be simply taken as the offset factor, or an exponentially weighted average can be constructed to enhance the response to points with particularly large differences. After calculation, the defect feature offset factor will serve as a numerical quantity representing the degree of abnormality of impurities in the current cable termination wrapping tape, for use by the subsequent defect assessment module.

[0062] In this embodiment, by calculating the absolute difference between the reflection characteristic value to be evaluated and the reflection characteristic value without defects, and using this as a basis to calculate the defect characteristic offset factor, the degree of electromagnetic response deviation of the cable terminal at the target frequency point can be effectively quantified. This accurately reflects the electromagnetic disturbances caused by minor structural anomalies or impurities that may exist in the wrapping tape area. This method does not rely on image processing or subjective judgment, has clear numerical logic and a stable calculation process, and helps to automate and standardize the assessment of cable terminal defects. Through a unified offset factor index, the comparability of detection results between multiple devices can be significantly improved, providing a reliable quantitative basis for intelligent inspection and early warning of power systems, and further improving the accuracy and efficiency of cable operation and maintenance management.

[0063] S104: Calculate the wrapping tape impurity defect characterization parameters based on each reflection characteristic value to be evaluated and the defect characteristic offset factor, and evaluate the defects of the wrapping tape part of the cable terminal to be evaluated through the wrapping tape impurity defect characterization parameters.

[0064] Among them, the wrapping tape impurity defect characterization parameter refers to the quantitative index calculated by computer equipment based on the reflection characteristic value to be evaluated and the defect characteristic offset factor. It is used to comprehensively reflect the degree of electromagnetic characteristic abnormality caused by impurity residue in the wrapping tape area of ​​the cable terminal and is the core parameter for defect assessment.

[0065] Specifically, after acquiring the sequence of reflection feature values ​​to be evaluated and the corresponding defect feature offset factors, the computer device can call the defect characterization module to perform the calculation operation of the defect characterization parameters. For example, each reflection feature value to be evaluated is multiplied by its corresponding or uniformly weighted defect feature offset factor to form a weighted offset value sequence; then, the weighted offset value sequence is normalized, and a single numerical index is generated through algorithms such as averaging, weighted fusion, or principal component analysis (PCA) as a defect characterization parameter for the wrapping tape impurities.

[0066] After calculating the defect characterization parameters, the computer equipment can activate the defect assessment module to compare the parameters with a pre-established defect-free baseline range or a multi-level threshold model. The threshold model can be set based on historical sample statistics, manual annotation experience, or standard operating condition test data, and is divided into multiple levels such as "normal," "minor defect," "moderate defect," and "severe defect" to provide differentiated diagnostic results.

[0067] It is understandable that by calculating the characterization parameters of the wrapping tape impurity defects based on the reflection characteristic value to be evaluated and the defect characteristic offset factor, and using this parameter as a unified index for defect evaluation, the local anomaly information of multiple frequency domain feature points can be effectively integrated and transformed into a single quantifiable and comparable comprehensive diagnostic result, thereby simplifying the evaluation process and improving judgment efficiency.

[0068] In the above embodiments, efficient identification of impurity defects in the cable terminal wrapping tape area can be achieved without damaging the cable structure, demonstrating significant technical advantages. First, by emitting high-frequency microwave signals in the 22GHz-30GHz band to the cable terminal wrapping tape area and acquiring the reflection coefficient curve, non-contact detection of the electromagnetic response characteristics inside the wrapping structure can be achieved. This avoids the risk of secondary damage caused by disassembling the cable for inspection, improving the safety and ease of operation of the detection process. Second, by selecting a preset number of minimum values ​​from the reflection coefficient curve as reflection characteristic values, combined with standard characteristic values ​​under corresponding defect-free conditions, the electromagnetic characteristic changes caused by the presence of impurities in the wrapping tape structure can be accurately captured, improving the sensitivity and accuracy of defect identification. Furthermore, by calculating the defect characteristic offset factor through differential absolute value, the degree of impurity disturbance to the electric field can be quantified, providing a clear numerical indicator basis for the detection process and facilitating the graded assessment of the severity of impurity defects. Finally, by constructing and quantitatively evaluating the characterization parameters of impurity defects in the wrapping tape, we can provide maintenance personnel with an intuitive and reliable basis for defect identification, promptly identify potential hazards, effectively reduce the risk of insulation degradation or breakdown faults caused by impurities, and improve the overall safety and reliability of cable terminal operation, which has important engineering application value.

[0069] In one embodiment, the step of transmitting a high-frequency microwave signal to the wrapping tape portion of a 10kV cable termination to be evaluated includes:

[0070] A vector network analyzer is used to transmit a high-frequency microwave signal to the 10kV cable terminal to be evaluated, so that the high-frequency microwave signal is transmitted through a coaxial cable and a rectangular waveguide and then vertically injected into the wrapping tape of the cable terminal to be evaluated.

[0071] Among them, a vector network analyzer is an electromagnetic parameter measurement device with the ability to transmit and receive radio frequency signals. It can generate high-frequency microwave signals and measure the reflection and transmission characteristics of signals in the object under test. It is the core device for realizing high-frequency signal injection and response analysis. Coaxial cable is a high-frequency transmission medium used to connect the vector network analyzer and the waveguide. It can effectively transmit microwave signals and maintain signal stability. A rectangular waveguide is a metal cavity structure with a rectangular cross-section, specifically designed for low-loss transmission of high-frequency microwaves. It can realize spatial guidance and directional control of microwave signals.

[0072] Specifically, the computer equipment is equipped with a control interface module, which can establish a communication connection with the vector network analyzer for automated control of the signal transmission process. During operation, the microwave scanning frequency band is first set according to the task parameters, and the vector network analyzer is instructed to generate a high-frequency microwave signal covering the frequency range of 22GHz to 30GHz; the signal transmitting end is connected to the rectangular waveguide through a calibrated coaxial cable.

[0073] Subsequently, to achieve high-precision and high-stability injection, the computer equipment guides the operator to vertically align the open end of the rectangular waveguide with the wrapping tape of the 10kV cable terminal, ensuring a tight fit between the waveguide outlet and the cable surface, and minimizing reflection interference caused by air gaps or tilt angles. Mechanical fixation can be achieved using a probe bracket or positioning clamp, while simultaneously activating an attitude detection module, such as a laser plane meter or tilt sensor, for direction correction, ensuring that the microwave signal can be stably injected into the target area vertically.

[0074] Furthermore, the computer equipment can receive parameter data returned by the vector network analyzer in real time, including frequency domain characteristics such as reflection coefficient and transmission coefficient, which are used to subsequently construct reflection coefficient curves and identify defect response characteristics. Parameters such as frequency step size, sweep rate, and transmission power are all uniformly set by the computer equipment in this process to ensure data quality and detection consistency.

[0075] In this embodiment, a high-frequency microwave signal is emitted by a vector network analyzer, and the microwave energy is stably guided to the wrapping tape area of ​​the cable terminal using a coaxial cable and a rectangular waveguide. This not only avoids the risk of secondary damage caused by cable structure disintegration but also enables non-contact, high-resolution detection of the local electromagnetic characteristics of the wrapping area. In particular, the vertical incidence method minimizes energy attenuation and multipath reflection caused by the incident angle, improving signal injection efficiency and detection accuracy. Overall, this method ensures equipment compatibility and detection sensitivity while facilitating the construction of a standardized and automated cable terminal inspection process, significantly improving the operational convenience and engineering feasibility of defect detection.

[0076] In one embodiment, the step of calculating the absolute value of the difference based on each reflection feature value to be evaluated and each defect-free reflection feature value includes:

[0077] Calculate the absolute value of the difference using the following expression:

[0078]

[0079] in, Indicates the first The absolute value of the difference, Indicates the first The difference between each reflection feature value to be evaluated and its corresponding defect-free reflection feature value Indicates the first One reflection characteristic value to be evaluated, Indicates the first One defect-free reflection characteristic value.

[0080] It is understandable that this differential absolute value calculation method can objectively quantify the deviation of local electromagnetic response at the cable termination wrapping area caused by impurities, defects, or structural anomalies, thus providing accurate and intuitive numerical indicators for defect identification. The use of absolute values ​​avoids positive and negative cancellation, ensuring that all abnormal deviations are effectively included in the analysis. This method facilitates automated calculation and batch processing, improves the sensitivity and accuracy of defect detection, supports the differentiation of different defect types and severity, and significantly enhances the reliability and practical value of cable termination quality assessment.

[0081] In one embodiment, the step of calculating the defect feature offset factor based on the absolute value of the difference includes:

[0082] Calculate the defect feature offset factor using the following expression:

[0083]

[0084] in, Indicates the defect feature offset factor. This represents the absolute value of the difference.

[0085] Specifically, the formula uses a composite structure of logarithmic and exponential functions to jointly express the overall offset and fluctuation amplitude. The numerator controls the growth rate of the value range by taking the logarithm of the total offset, thus avoiding the amplification of outliers. The denominator constructs an exponential function through the range to amplify and penalize fluctuations between frequency points, thereby enhancing the sensitivity to unstable offsets.

[0086] The defect feature offset factor calculated using the above formula, while fully considering the overall offset intensity, introduces a penalty mechanism for frequency fluctuation amplitude. This ensures that the defect feature offset factor not only reflects the abnormal cumulative effect caused by impurities in the cable terminal wrapping area, but also has the ability to identify imbalances in electromagnetic response consistency. The numerator uses a logarithmic function to compress the influence of large offsets, enhancing the resolution of medium- and low-offset anomalies; the denominator uses an exponential function to amplify the range, improving the ability to suppress abnormal and severe fluctuations, thereby avoiding the risk of misjudging the overall offset by local ranges.

[0087] Overall, the formula has the advantages of strong robustness, controllable values, and high diagnostic sensitivity. It is easy to standardize and deploy in automated testing systems to achieve stable, refined, and quantitative assessment of cable terminal defect status. This helps to improve the accuracy of defect identification and the consistency of system judgment, and has significant engineering applicability and practical promotion value.

[0088] In one embodiment, the step of calculating the characterization parameters of the wrapping tape impurity defects based on each reflection feature value to be evaluated and the defect feature offset factor includes:

[0089] Calculate the characterization parameters of impurity defects in the wrapping tape using the following expression:

[0090]

[0091] in, This indicates the parameters characterizing impurities and defects in the wrapping tape. Indicates the defect feature offset factor. Indicates the first One reflection characteristic value to be evaluated.

[0092] Specifically, the formula adopts a weighted hybrid structure, which integrates information on both defect strength and response structural asymmetry in the molecule, and uses the cube root function to normalize and constrain the denominator to form a comprehensive characterization value under a unified scale.

[0093] By using the above expression to calculate the characterization parameters of impurities in the cable wrapping tape, the influence of minute impurities that may exist in the cable terminal wrapping tape area on the electromagnetic wave propagation characteristics can be accurately reflected in multiple dimensions. In the numerator, the 2 / 3 power term of the defect feature offset factor ensures that the defect intensity information is retained while avoiding over-amplification, while the deviation of the reflection value and taking the logarithm further reveal the asymmetry between different frequency points and the overall low trend, enhancing the ability to identify local hidden impurity disturbances.

[0094] Furthermore, the cube root form of the range in the denominator introduces a normalization constraint on the frequency domain fluctuation amplitude, giving the numerical expression of the wrapping tape impurity defect characterization parameter good smoothness and comparability, effectively avoiding misjudgments caused by distortion at specific frequency points. Compared to a single characteristic parameter, the wrapping tape impurity defect characterization parameter, as a comprehensive parameter integrating multi-level information, can make a more accurate and detailed judgment on the structural integrity of the cable terminal.

[0095] Therefore, this calculation method not only improves the sensitivity of impurity and defect identification, but also enhances the system's adaptability to minor abnormal changes in complex electromagnetic response modes, providing a solid numerical foundation for building an automated and standardized cable quality assessment system, and possessing good engineering practicality and scalability.

[0096] In one embodiment, the step of evaluating defects in the wrapping tape portion of the cable termination to be evaluated, using wrapping tape impurity defect characterization parameters, includes:

[0097] When the defect characterization parameter of the wrapping tape is not greater than the first preset threshold, there are no impurities in the wrapping tape part of the cable terminal to be evaluated.

[0098] When the defect characterization parameter of the wrapping tape impurities is greater than the first preset threshold and not greater than the second preset threshold, the wrapping tape part of the cable terminal to be evaluated contains dust impurities.

[0099] When the defect characterization parameter of the wrapping tape is greater than the second preset threshold, the wrapping tape part of the cable terminal to be evaluated contains metallic impurities.

[0100] The first preset threshold is a critical value for impurity identification determined through extensive experimental data and statistical analysis. When this value is not exceeded, it indicates that no abnormal response was detected within the detection area. The second preset threshold is a critical value between the normal state and the state of severe impurity contamination, used to further refine the impurity type. Dust impurities refer to non-conductive particles or dust-like foreign matter that may remain on the wrapping tape interface during installation; their impact on microwave reflection characteristics is moderate. Metallic impurities refer to metallic particles with high dielectric constants or conductivity, which may significantly disturb the electric field distribution and induce strong reflection changes, belonging to a more dangerous type of defect.

[0101] It should be noted that, in one embodiment, the first preset threshold is 3.817, and the second preset threshold is 5.639. Both the first preset threshold of 3.817 and the second preset threshold of 5.639 are empirical parameters obtained through fitting and statistical analysis of a large amount of experimental data, used to distinguish the degree of impurity defects in the cable terminal wrapping tape area. Their values ​​are calculated by combining actual detection data from cable terminal samples under multiple known conditions, such as no impurities, dust impurities, and metal particle impurities, to determine the distribution range of the wrapping tape impurity defect characterization parameter values, and a reasonable dividing point is determined using the statistical interval of the distribution boundary. Through normalization, fluctuation suppression, and response quantization, it was found that when the wrapping tape impurity defect characterization parameter... When the reflection response in the sample is stable, with small fluctuations and insignificant microwave characteristic value shift, it conforms to the characteristics of an impurity-free state. However, when the characterization parameter λ for impurity defects in the wrapping tape is greater than 5.639, the sample mostly contains metallic particles with strong electromagnetic disturbance effects, and its reflection curve is severely distorted, exhibiting significant electric field inhomogeneity. Therefore, this value is set as the lower limit for judging metallic impurities. On the other hand, the intermediate range ( The corresponding particles are mostly low-dielectric, non-conductive dust or impurity residues. Their impact on microwave disturbance falls within a identifiable but not severe intermediate range, thus they are classified as dust and impurity zones, facilitating automatic differentiation of impurity types. Therefore, the setting of these two thresholds combines theoretical models with actual sample statistics, ensuring both the physical rationality of the judgment results and good engineering stability and adaptability for wider application. They can be directly applied to the automated identification and intelligent assessment of cable terminal wrapping tape defects by computer equipment.

[0102] Specifically, the computer device includes a defect identification module. This module receives and analyzes the values ​​of the characterization parameters of impurity defects in the wrapping tape and compares them with multiple built-in discrimination thresholds. The system pre-stores a first preset threshold and a second preset threshold, which are used to classify the three judgment results as "no impurities," "containing dust impurities," and "containing metal impurities," respectively.

[0103] In practical applications, after the computer equipment completes the microwave signal acquisition and defect characterization parameter calculation of the wrapping tape area, it will automatically trigger the judgment logic process. First, it determines whether λ is less than or equal to the first preset threshold. If the condition is met, the "no impurities" evaluation result is output. If λ is greater than the first threshold but does not exceed the second threshold, it is identified as "containing dust impurities". If λ is greater than the second preset threshold, the system confirms that the current part contains "metal impurities".

[0104] It is understandable that by comparing the characterization parameters of impurities in the wrapping tape with multiple preset thresholds in segments, the state of impurities in the wrapping tape can be automatically and hierarchically identified. This helps to distinguish between three risk levels: normal operating conditions, light contamination, and severe impurities, thus improving the certainty of the judgment. Using a multi-threshold discrimination mechanism can effectively improve the system's accuracy in identifying differences in electromagnetic response caused by different types of impurities. Simultaneously, this approach balances the finesse of the judgment with engineering operability, not only improving the accuracy and responsiveness of defect detection but also enhancing the practicality and reliability of the detection system in actual field deployments. Ultimately, this process provides maintenance personnel with clear and actionable judgment results, supporting more timely defect repair and system security assurance.

[0105] The following describes the 10kV cable terminal wrapping tape impurity defect detection device provided in the embodiments of this application. The 10kV cable terminal wrapping tape impurity defect detection device described below can be referred to in correspondence with the 10kV cable terminal wrapping tape impurity defect detection method described above. Figure 2 As shown, this application provides a device for detecting impurity defects in the wrapping tape of a 10kV cable termination. The device includes:

[0106] The reflection coefficient curve acquisition module 201 is used to transmit a high-frequency microwave signal to the wrapping tape part of the 10kV cable terminal to be evaluated and acquire the reflection coefficient curve of the reflected wave. The frequency band of the high-frequency microwave signal is 22GHz~30GHz.

[0107] The reflection feature value selection module 202 is used to select a preset number of minimum values ​​from the reflection coefficient curve as reflection feature values ​​to be evaluated, and select the corresponding defect-free reflection feature value according to the frequency of each reflection feature value to be evaluated.

[0108] The defect feature offset factor calculation module 203 is used to calculate the absolute value of the difference based on each reflection feature value to be evaluated and each defect-free reflection feature value, and to calculate the defect feature offset factor based on the absolute value of the difference.

[0109] The wrapping tape impurity defect assessment module 204 is used to calculate the wrapping tape impurity defect characterization parameters based on each reflection characteristic value to be assessed and the defect characteristic offset factor, and to assess the defects of the wrapping tape part of the cable terminal to be assessed through the wrapping tape impurity defect characterization parameters.

[0110] In one embodiment, the reflection coefficient curve acquisition module 201 includes:

[0111] The high-frequency microwave signal transmitting unit is used to transmit high-frequency microwave signals to the 10kV cable terminal to be evaluated using a vector network analyzer, so that the high-frequency microwave signal is transmitted through a coaxial cable and a rectangular waveguide and then vertically injected into the wrapping tape part of the cable terminal to be evaluated.

[0112] In one embodiment, the defect feature offset factor calculation module 203 includes:

[0113] The absolute difference calculation unit is used to calculate the absolute difference according to the following expression:

[0114]

[0115] in, Indicates the first The absolute value of the difference, Indicates the first The difference between each reflection feature value to be evaluated and its corresponding defect-free reflection feature value Indicates the first One reflection characteristic value to be evaluated, Indicates the first One defect-free reflection characteristic value.

[0116] In one embodiment, the defect feature offset factor calculation module 203 includes:

[0117] The defect feature offset factor calculation unit is used to calculate the defect feature offset factor according to the following expression:

[0118]

[0119] in, Indicates the defect feature offset factor. This represents the absolute value of the difference.

[0120] In one embodiment, the wrapping tape impurity defect assessment module 204 includes:

[0121] The wrapping tape impurity defect characterization parameter calculation unit is used to calculate the wrapping tape impurity defect characterization parameters according to the following expression:

[0122]

[0123] in, This indicates the parameters characterizing impurities and defects in the wrapping tape. Indicates the defect feature offset factor. Indicates the first One reflection characteristic value to be evaluated.

[0124] In one embodiment, the wrapping tape impurity defect assessment module 204 includes:

[0125] The first wrapping tape impurity defect assessment unit is used to determine that there are no impurities in the wrapping tape part of the cable terminal to be assessed when the characterization parameter of the wrapping tape impurity defect is not greater than the first preset threshold.

[0126] The second wrapping tape impurity defect assessment unit is used to determine that the wrapping tape part of the cable terminal to be assessed contains dust impurities when the wrapping tape impurity defect characterization parameter is greater than the first preset threshold and not greater than the second preset threshold.

[0127] The third wrapping tape impurity defect assessment unit is used to determine that the wrapping tape portion of the cable terminal to be assessed contains metallic impurities when the characterization parameter of the wrapping tape impurity defect is greater than the second preset threshold.

[0128] In one embodiment, the first preset threshold is 3.817 and the second preset threshold is 5.639.

[0129] In one embodiment, this application also provides a storage medium storing computer-readable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the 10kV cable terminal wrapping tape impurity defect detection method as described in any of the above embodiments.

[0130] In one embodiment, this application also provides a computer device storing computer-readable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the 10kV cable terminal wrapping tape impurity defect detection method as described in any of the above embodiments.

[0131] Indicatively, such as Figure 3 As shown, Figure 3 This is a schematic diagram of the internal structure of a computer device 300 provided in an embodiment of this application. The computer device 300 can be provided as a server. (Refer to...) Figure 3 The computer device 300 includes a processing component 302, which further includes one or more processors, and memory resources represented by memory 301 for storing instructions, such as application programs, that can be executed by the processing component 302. The application programs stored in memory 301 may include one or more modules, each corresponding to a set of instructions. Furthermore, the processing component 302 is configured to execute instructions to perform the 10kV cable termination wrapping tape impurity defect detection method of any of the above embodiments.

[0132] The computer device 300 may also include a power supply component 303 configured to perform power management of the computer device 300, a wired or wireless network interface 304 configured to connect the computer device 300 to a network, and an input / output (I / O) interface 305. The computer device 300 may operate on an operating system stored in memory 301, such as Windows Server™, Mac OS X™, Unix™, Linux™, Free BSD™, or similar.

[0133] Those skilled in the art will understand that Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0134] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this document, "a," "an," "the," "the," and "its" may also include plural forms unless the context clearly indicates otherwise. "Multiple" refers to at least two, such as 2, 3, 5, or 8, etc. "And / or" includes any and all combinations of the related listed items.

[0135] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0136] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting a 10 kV cable termination wrap tape impurity defect, characterized by, The method comprises: A high-frequency microwave signal is emitted to the wrapping tape part of the 10kV cable terminal to be evaluated, and a reflection coefficient curve of a reflected wave is obtained, wherein the frequency band of the high-frequency microwave signal is 22GHz-30GHz; A preset number of minimum values are selected from the reflection coefficient curve as evaluation reflection characteristic values, and a corresponding defect-free reflection characteristic value is selected at the frequency of each evaluation reflection characteristic value; Difference absolute values are calculated according to each evaluation reflection characteristic value and each defect-free reflection characteristic value, and a defect characteristic offset factor is calculated according to the difference absolute values; A wrapping tape impurity defect representation parameter is calculated according to each evaluation reflection characteristic value and the defect characteristic offset factor, and the wrapping tape part of the 10kV cable terminal to be evaluated is evaluated for defects through the wrapping tape impurity defect representation parameter. The wrapping tape impurity defect representation parameter is calculated according to the following expression: wherein denotes the wrapping tape impurity defect characterization parameter, denotes the defect feature offset factor, denotes the i-th of the to-be-evaluated reflection feature values.

2. The method of claim 1, wherein the 10 kV cable termination wrap tape impurity defect detection method is characterized by, The step of emitting the high-frequency microwave signal to the wrapping tape part of the 10kV cable terminal to be evaluated comprises: The high-frequency microwave signal is emitted to the 10kV cable terminal to be evaluated by using a vector network analyzer, so that the high-frequency microwave signal is vertically incident on the wrapping tape part of the 10kV cable terminal to be evaluated after being transmitted through a coaxial cable and a rectangular waveguide.

3. The 10 kV cable termination wrap tape impurity defect detection method of claim 1, wherein, The step of calculating the difference absolute values according to each evaluation reflection characteristic value and each defect-free reflection characteristic value comprises: The difference absolute values are calculated according to the following expression: wherein, represents the first difference absolute value, represents the first difference between the first evaluated reflection characteristic value and its corresponding non-defective reflection characteristic value, represents the first evaluated reflection characteristic value, represents the first non-defective reflection characteristic value.

4. The method of claim 1, wherein the 10 kV cable termination wrap tape impurity defect detection method is characterized by, The step of calculating the defect characteristic offset factor according to the difference absolute values comprises: The defect characteristic offset factor is calculated according to the following expression: wherein, denotes the defect feature offset factor, denotes the difference absolute value.

5. The method of claim 1, wherein the 10 kV cable termination wrap tape foreign object defect detection method is characterized by, The step of evaluating the wrapping tape part of the 10kV cable terminal to be evaluated for defects through the wrapping tape impurity defect representation parameter comprises: When the wrapping tape impurity defect representation parameter is not greater than a first preset threshold, the wrapping tape part of the 10kV cable terminal to be evaluated is free of impurities; When the wrapping tape impurity defect representation parameter is greater than the first preset threshold and not greater than a second preset threshold, the wrapping tape part of the 10kV cable terminal to be evaluated contains dust impurities; When the wrapping tape impurity defect representation parameter is greater than the second preset threshold, the wrapping tape part of the 10kV cable terminal to be evaluated contains metal impurities.

6. The method of claim 5, wherein the 10 kV cable termination wrap tape impurity defect detection method is characterized by, The first preset threshold is 3.817, and the second preset threshold is 5.

639.

7. A 10 kV cable termination wrap tape impurity defect detection apparatus, characterized by, The device comprises: A reflection coefficient curve acquisition module is configured to emit a high-frequency microwave signal to the wrapping tape part of the 10kV cable terminal to be evaluated, and obtain a reflection coefficient curve of a reflected wave, wherein the frequency band of the high-frequency microwave signal is 22GHz-30GHz; A reflection characteristic value selection module is configured to select a preset number of minimum values from the reflection coefficient curve as evaluation reflection characteristic values, and select a corresponding defect-free reflection characteristic value at the frequency of each evaluation reflection characteristic value; A defect characteristic offset factor calculation module is configured to calculate difference absolute values according to each evaluation reflection characteristic value and each defect-free reflection characteristic value, and calculate a defect characteristic offset factor according to the difference absolute values; The wrapping tape impurity defect evaluation module is configured to calculate a wrapping tape impurity defect characterization parameter according to the respective to-be-evaluated reflection characteristic values and the defect characteristic offset factor, and perform defect evaluation on the wrapping tape part of the to-be-evaluated cable terminal through the wrapping tape impurity defect characterization parameter. The wrapping tape impurity defect characterization parameter is calculated according to the following expression: wherein represents the wrapping tape impurity defect characterization parameter, represents the defect feature offset factor, represents the i th of the reflection feature values to be evaluated.

8. A storage medium characterized by: The storage medium stores computer readable instructions, and the computer readable instructions are executed by one or more processors to make the one or more processors execute the steps of the 10kV cable terminal wrapping tape impurity defect detection method according to any one of claims 1 to 6.

9. A computer device, comprising: Comprise: One or more processors, and a memory; The memory stores computer readable instructions, and the computer readable instructions are executed by the one or more processors to execute the steps of the 10kV cable terminal wrapping tape impurity defect detection method according to any one of claims 1 to 6.

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