Method and system for detecting and diagnosing ablation of buffer layer of high-voltage cable

Abstract

The invention belongs to the technical field of high-voltage cable operation and maintenance, and relates to a high-voltage cable buffer layer ablation detection and diagnosis method and system.The system obtains temperature characteristic data, waveform graph data and powder performance data of a to-be-evaluated area through a three-mode data acquisition module; the comprehensive evaluation model construction module constructs an ablation comprehensive evaluation model based on the collected data, and preliminarily identifies the ablation state of the buffer layer; the ablation state grading module carries out grading identification on the ablation state according to the ablation risk score output by the comprehensive evaluation model; the operation and maintenance strategy generation module directly associates the risk assessment result with an operation and maintenance decision, and generates an executable early warning mechanism and a response strategy; and the evaluation report output module is used for generating a comprehensive evaluation result and a fault cause analysis report. According to the method and the system, the ablation state of the buffer layer of the high-voltage cable can be diagnosed, and the fault detection precision and the scientificity of operation and maintenance decision are improved.

Description

Technical Field

[0001] This invention relates to the field of high-voltage cable operation and maintenance technology, specifically to a method and system for detecting and diagnosing the ablation of the buffer layer of a high-voltage cable. Background Technology

[0002] Erosion of the buffer layer in high-voltage cables is a common fault in power systems. Early detection and accurate diagnosis are crucial for preventing major accidents such as cable breakdown and short circuits.

[0003] In the existing technology, the detection methods for high-voltage cable buffer layer ablation mostly rely on single-mode signals or adopt simple multi-mode fusion strategies, resulting in low accuracy of early ablation identification, high false positive and false negative rates, and difficulty in accurately identifying the cause of the fault.

[0004] To address this, invention patent CN120337034A discloses a method and system for detecting ablation of the buffer layer of high-voltage cables based on waveform spectra, comprising the following steps: S1: acquiring multimodal data of the high-voltage cable and preprocessing it; S2: extracting waveform time-frequency domain features, vibration features, and infrared features, and integrating them into a multimodal feature vector training set; S3: constructing an intelligent analysis model based on a multimodal deep learning network, and training it based on the multimodal feature vector training set to obtain the trained intelligent analysis model; S4: inputting the real-time acquired multimodal data into the trained intelligent analysis model to obtain ablation results, including whether ablation exists, the location of ablation, and the severity level; S5: based on the output of the intelligent analysis model, combined with the real-time acquired multimodal signals, visualizing the ablation results through waveform overlay and 3D modeling, and triggering a graded alarm mechanism according to the severity level to push real-time notifications. This invention significantly improves the efficiency, accuracy, and reliability of high-voltage cable fault detection.

[0005] The above-mentioned technical solutions have made progress in multimodal data collaborative analysis and intelligent model applications, but the following technical problems still exist: Current multimodal fusion is mainly based on data-driven attention mechanisms, which do not involve the nonlinear coupling relationship between cable structural parameters and the ablation process, resulting in insufficient adaptability under complex working conditions; it is difficult to accurately identify the root cause of the fault, reducing the pertinence of operation and maintenance decisions.

[0006] In view of this, it is very necessary to provide a method and system for detecting and diagnosing the ablation of the buffer layer of high-voltage cables in order to solve the above-mentioned defects in the prior art. Summary of the Invention

[0007] The purpose of this invention is to address the problems in the existing multimodal fusion technology, which is mainly based on data-driven attention mechanisms and does not involve the nonlinear coupling relationship between cable structural parameters and the ablation process, resulting in insufficient adaptability under complex working conditions; difficulty in accurately identifying the root cause of the fault and reducing the pertinence of operation and maintenance decisions. In response to the above-mentioned technical defects of the existing technology, this invention provides a method and system for detecting and diagnosing the ablation of the buffer layer of high-voltage cables to solve the above-mentioned technical problems.

[0008] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for detecting and diagnosing the ablation of the buffer layer of a high-voltage cable, comprising the following steps: Step S1: Three-modal data acquisition steps; acquire temperature characteristic data, waveform spectrum data and powder performance data of the area to be evaluated; Step S2: Constructing a comprehensive evaluation model; Based on the collected temperature characteristic data, waveform spectrum data, and powder performance data, a comprehensive evaluation model for the high-voltage cable buffer layer is constructed. This comprehensive evaluation model includes components representing coupling strength, comprehensive state, and dynamic growth. A risk score is output through a normalized S-shaped function. This allows for a precise characterization of the entire cycle of buffer layer ablation, from microscopic degradation to macroscopic failure. Step S3: The steps for assessing the ablation status; based on the risk score output by the assessment model, identify and classify the ablation status; Step S4: Steps for generating operation and maintenance strategies; conduct a preliminary safety risk assessment of the ablation state, directly link the risk assessment results with operation and maintenance decisions, form an executable early warning mechanism, and accurately locate the cause of the failure; Step S5: The step of generating the evaluation result report; outputting the comprehensive evaluation results and the fault cause analysis report.

[0009] Secondly, the present invention also provides a detection and diagnosis system for the ablation of the buffer layer of a high-voltage cable, comprising: The three-modal data acquisition module is used to acquire temperature characteristic data, waveform spectrum data and powder performance data of the area to be evaluated. The comprehensive evaluation model construction module constructs an ablation comprehensive evaluation model based on the collected data to preliminarily identify the ablation state of the buffer layer. The ablation status classification module classifies and identifies the ablation status based on the ablation risk score output by the comprehensive evaluation model. The operation and maintenance strategy generation module is used to directly link risk assessment results with operation and maintenance decisions, and generate executable early warning mechanisms and response strategies. The assessment report output module is used to generate comprehensive assessment results and fault cause analysis reports.

[0010] The modules work together to achieve multimodal fusion assessment, risk quantification and intelligent diagnosis of the ablation state of the high-voltage cable buffer layer, significantly improving the accuracy of fault detection and the scientific nature of operation and maintenance decisions.

[0011] The beneficial effects of this invention are as follows: This invention significantly improves the detection accuracy and precision of high-voltage cable buffer layer ablation by acquiring and fusing three-modal data. By obtaining temperature, waveform spectra, and powder data, the accuracy and timeliness of the data are ensured, providing a reliable data foundation for subsequent analysis.

[0012] This invention, by constructing a comprehensive evaluation model, achieves preliminary identification and analysis of the ablation state, improving the accuracy of early ablation identification and providing a comprehensive and dynamic assessment of the ablation state of the buffer layer. This process enhances the model's adaptability, comprehensively considering environmental factors and cable structural parameters to adapt to different operating conditions; it helps to quickly identify potential ablation risks and provides a scientific basis for risk assessment.

[0013] This invention classifies and identifies ablation states based on risk scores output by a comprehensive evaluation model and performs quantitative assessments of safety risks, providing clear guidance for operation and maintenance decisions. This step effectively reduces potential failure risks caused by ablation problems and enhances the safety of equipment operation.

[0014] This invention directly links risk assessment results with operation and maintenance decisions, forming an executable early warning mechanism and response strategy. This enables precise location of fault causes, making operation and maintenance work more refined and scientific, and improving the pertinence, scientific nature, real-time nature and effectiveness of operation and maintenance decisions.

[0015] This invention provides detailed information for subsequent decision-making and maintenance operations by generating comprehensive evaluation results and fault cause analysis reports. This report not only helps guide equipment maintenance and repair but also provides strong support for long-term operational monitoring.

[0016] This invention forms an integrated and scientific method for detecting and diagnosing high-voltage cable buffer layer erosion through the collaborative work of data acquisition, assessment model construction, ablation state classification assessment, operation and maintenance strategy generation, and assessment report output. By closely cooperating and effectively integrating various modules, it can significantly improve the fault detection accuracy of high-voltage cables, optimize the operation and maintenance decision-making process, reduce manual intervention, and improve the stability and safety of equipment.

[0017] Therefore, it is evident that the present invention has outstanding substantive features and significant progress compared with the prior art, and the beneficial effects of its implementation are also obvious. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a flowchart of a method for detecting and diagnosing the ablation of the buffer layer in a high-voltage cable; Figure 2 This is a schematic diagram of a detection and diagnosis system for the ablation of the buffer layer of a high-voltage cable. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following implementation methods.

[0021] Example 1: like Figure 1 As shown in the figure, this embodiment provides a method for detecting and diagnosing the ablation of the buffer layer of a high-voltage cable, which includes the following steps: Step S1: Three-modal data acquisition steps; acquire temperature characteristic data, waveform spectrum data and powder performance data of the area to be evaluated; Step S2: Constructing a comprehensive evaluation model; Based on the collected temperature characteristic data, waveform spectrum data, and powder performance data, a comprehensive evaluation model for the high-voltage cable buffer layer is constructed. This comprehensive evaluation model includes components representing coupling strength, comprehensive state, and dynamic growth. A risk score is output through a normalized S-shaped function. This allows for a precise characterization of the entire cycle of buffer layer ablation, from microscopic degradation to macroscopic failure. Step S3: The steps for assessing the ablation status; based on the risk score output by the assessment model, identify and classify the ablation status; Step S4: Steps for generating operation and maintenance strategies; conduct a preliminary safety risk assessment of the ablation state, directly link the risk assessment results with operation and maintenance decisions, form an executable early warning mechanism, and accurately locate the cause of the failure; Step S5: The step of generating the evaluation result report; outputting the comprehensive evaluation results and the fault cause analysis report.

[0022] Step S1 includes the steps of collecting temperature characteristic data, collecting waveform spectrum data, and collecting powder performance data. Step S11, the step of collecting temperature characteristic data: Continuous temperature monitoring is performed on the surface of the cable buffer layer or key areas using an infrared thermal imager or fiber optic temperature sensor. The sampling frequency is once per minute, the temperature range is 20°C to 120°C, and the accuracy is ±0.5°C. Temperature characteristic parameters, including average temperature, are extracted. Temperature gradient used to characterize the rate of temperature change per unit distance Maximum temperature .

[0023] Temperature data can be acquired using the FLIR A315 infrared thermal imager. The FLIR A315 can be flexibly installed in any area requiring monitoring, detecting temperature differences in real time and visualizing the temperature distribution, facilitating rapid identification of thermal anomalies in the cable buffer layer. Alternatively, a fiber optic temperature sensor, model FBG-4000, can also be used for temperature monitoring. This sensor uses fiber Bragg grating (FBG) technology for temperature acquisition, featuring high accuracy, resistance to electromagnetic interference, and high reliability, making it suitable for continuous temperature monitoring in complex environments such as high-voltage cables. Temperature data acquired through fiber optic sensors exhibits strong high-temperature resistance and long-term stability, helping to accurately capture temperature changes in the cable buffer layer.

[0024] Step S12, the steps for acquiring waveform spectrum data: A wideband pulse signal with a frequency range of 100Hz to 1MHz was injected into the cable conductor using the pulsed current method, and the reflected waveform was acquired by a high-frequency current sensor with a bandwidth of 10kHz to 50MHz mounted on the aluminum sheath. Based on the acquired waveform data, characteristic parameters, including the waveform distortion coefficient, were extracted. This is used to represent the percentage difference in amplitude between the distorted waveform and the standard waveform; high-frequency component energy ratio. , used to reflect the proportion of energy in the frequency band above 1MHz to the total energy; and the number of partial discharge pulses N, representing the number of pulses occurring per minute.

[0025] Step S13, the step of collecting powder performance data: Powder samples generated during the ablation process are collected using a miniature negative pressure adsorption device at cable terminations, intermediate joint inspection ports, or other locations accessible to the buffer layer. The collected powder samples undergo performance testing, including measuring the dielectric loss value. The test conditions were 1kV voltage and 50Hz frequency; the particle size distribution of the powder sample was determined. The particle size distribution was analyzed using a laser particle size analyzer, and the carbonization rate of the powder was calculated. This refers to the mass loss rate measured after the sample has been burned at 550°C for 3 hours.

[0026] By collecting temperature, waveform, and powder data, the real-time status of the cable buffer layer can be accurately monitored, providing multi-dimensional data support for subsequent ablation analysis and evaluation. The accuracy and timeliness of this data provide a reliable basis for subsequent diagnosis, effectively improving the accuracy and response speed of fault detection.

[0027] In step S2: Based on the three-modal original feature data, an ablation comprehensive assessment model is constructed, and an ablation risk score is calculated. Starting from the multiphysics coupling mechanism, core components characterizing coupling strength, comprehensive index, and dynamic growth were constructed. Finally, the ablation risk score was obtained through a normalized S-shaped function. This enables accurate characterization of the entire ablation process of the buffer layer, from microscopic degradation to macroscopic failure. The calculation process for each core component and the ablation risk score is as follows: Step S21: Calculate the multimodal coupling strength factor. Steps: The multimodal coupling strength factor is used to quantify the nonlinear synergistic degradation effect among operating temperature, partial discharge, and material dielectric loss. Its construction is based on the theory of accelerated aging of insulating materials under combined electro-thermal stress. Specifically, increased temperature exacerbates partial discharge activity by reducing the carrier migration activation energy, while the active substances and Joule heat generated by the discharge further promote the destruction of the material's chemical structure and polarization loss, manifesting as increased dielectric loss. Temperature, partial discharge, and material dielectric loss constitute a positive feedback loop, significantly accelerating insulation degradation. The mathematical expression is: ; Parameter description: Reference temperature, usually selected as room temperature 293.15K; Temperature effect index, based on the thermal aging test data of XLPE insulated cables, is taken as 2.5; The apparent activation energy of the discharge process is taken as... ; : Ideal gas constant, taken as 8.314.

[0028] Step S22, calculate the thermo-electro-chemical composite index Steps: This method is used to comprehensively characterize the severe ablation state determined by localized overheating concentration effects, high-frequency discharge energy, and powder product characteristics. It integrates principles of heat conduction, electromagnetic wave energy deposition, and materials chemical analysis, aiming to capture characteristics that lead to irreversible degradation of insulation performance. The calculation formula is as follows: ; Parameter description: The thermal conductivity of the buffer layer material, for a semiconducting resistive water strip, is taken as... ; : Thermal diffusivity of the buffer layer, taken as ; The reference threshold for carbonization rate is 5%, based on the results of thermogravimetric analysis (TGA). The characteristic length affected by powder particle size is taken as 25 μm based on the particle packing and conductivity model.

[0029] Step S23, calculate the dynamic risk growth factor. Steps: The dynamic risk growth factor is used to describe the nonlinear acceleration phenomenon in the ablation process, with particular attention to the dynamic coupling between the frequency of discharge activity and the carbonization process of the material. The construction of the dynamic risk growth factor is based on the idea of ​​the autocatalytic process model in chemical reaction kinetics; specifically, the reaction products, namely conductive carbides, themselves change the electric field distribution, thereby accelerating the discharge activity and promoting further carbonization reactions. The calculation formula is: ; Parameter description: The critical frequency of discharge activity, based on phase-resolved partial discharge (PRPD) statistical analysis and Weibull distribution, is set at 50 times / min. The critical threshold for carbonization rate is set at 8%, based on the results of material scanning electron microscopy (SEM) and resistivity testing.

[0030] Step S24, calculate the ablation risk score. Steps: The ablation risk score is obtained by normalizing the output using the classic S-shaped growth curve model. The S-shaped growth curve model is widely used in systematic reliability assessment and failure prediction. It can smoothly map complex multi-factor coupled inputs to a defined risk level range, effectively avoiding abrupt changes near the threshold and ensuring the stability of the assessment results. The calculation formula is: ; in, The scaling factor is set to 0.15 based on historical fault data inversion and analysis.

[0031] By constructing a multimodal coupling strength factor, a thermo-electro-chemical comprehensive index, and a dynamic risk growth factor, the nonlinear synergistic effect in the ablation process can be accurately quantified. The ablation risk score Rscore is output through the S-shaped growth curve model, realizing the full-cycle accurate characterization of the ablation state of the high-voltage cable buffer layer. This not only provides a scientific basis for risk quantification and staged ablation judgment, improving the accuracy and reliability of ablation state identification, but also provides a reliable quantitative basis for operation and maintenance decisions.

[0032] In step S3: Based on ablation risk score Based on the numerical range, the buffer layer ablation process can be preliminarily divided into three stages, each corresponding to a typical range of characteristic parameters: Early ablation stage ( 20): At this stage, the local microstructure begins to deteriorate. Although the characteristic signals are weak, signs of ablation can be detected. Parameters such as temperature, partial discharge activity, and dielectric loss are all in the low range. Specifically, the buffer layer material begins to show initial thermal aging and slight hydrolysis, the waveform exhibits identifiable initial distortion, and the powder includes incompletely carbonized aluminum hydroxide. At this time, the typical parameter range is: <55℃, <0.15, <0.018, <2%.

[0033] Intermediate ablation stage (20 60): In this stage, the degradation process accelerates, hot spots form in localized areas, and stable discharges occur, resulting in significantly enhanced characteristic signals. Parameters show a decline in the electrical performance of the buffer layer, and discharge activity gradually increases. Specifically, the volume resistivity of the buffer layer decreases significantly, gap discharge activity becomes more active, and the powder consists of a mixture of carbonized particles and aluminum hydroxide. Typical parameter range: 55℃ 80℃, 0.15 0.45, 0.018 0.045, 2% 7%.

[0034] Late ablation stage ( At this stage, the buffer layer material has severely deteriorated, facing a high risk of thermal runaway and violent discharge. Insulation performance is severely reduced, and the material's thermal stability and electrical properties deteriorate significantly. Specifically, the buffer layer partially loses its function, the insulation layer faces direct threat, and the powder includes conductive carbides. Typical parameter ranges are: 80℃ 0.45, 0.045, 7%.

[0035] ablation risk score The ablation process of the buffer layer is divided into stages, enabling quantifiable identification of the entire process from microscopic degradation to thermal runaway. The parameter ranges for each stage are clearly defined, accurately reflecting the dynamic evolution characteristics of temperature, discharge, and carbonization rate. This provides a basis for early warning and condition assessment of the ablation process, helps to achieve graded diagnosis and trend prediction of fault risks, and improves the safety and reliability of high-voltage cable operation.

[0036] In step S4, a preliminary safety assessment of the ablation state is conducted, and the risk assessment results are combined with operation and maintenance decisions to form an executable early warning mechanism, thereby enabling timely identification and effective response to potential risks. Simultaneously, the operation and maintenance strategy also includes precise location of the fault causes to facilitate the development of targeted prevention and remediation measures.

[0037] This step includes generating an early warning mechanism and accurately locating the cause of the failure: Step S41, the steps for generating the early warning mechanism: Based on ablation risk score The values ​​are used to classify risk levels, and corresponding operation and maintenance strategies are formulated for each risk level.

[0038] exist Under a safety condition of <15, the buffer layer is stable, and no risk of ablation is detected. An operational strategy is generated to continue routine inspections and conduct periodic preventative tests.

[0039] When 15< is detected When the value is less than 35, it is defined as a state of alert, indicating early signs of ablation that require attention. The maintenance strategy is updated to: increase the monitoring frequency to once a week, use online monitoring devices to track the changing trends of characteristic parameters, and incorporate them into the recent maintenance plan.

[0040] When 35 A reading below 55 indicates a warning state, signifying that ablation has occurred and equipment reliability is declining. The maintenance strategy involves increasing monitoring frequency to once daily or implementing real-time monitoring, developing and implementing a detailed repair plan within one month, and reducing line load as necessary to mitigate risk.

[0041] when At 55°C, the situation was deemed dangerous. At this point, the ablation was severe, and serious accidents such as insulation breakdown could occur at any time. The maintenance strategy at this point was to immediately issue an emergency shutdown and maintenance order to ensure equipment safety.

[0042] Step S42, the steps to accurately locate the cause of the fault: By combining the relationships between characteristic parameters, the root cause of ablation can be diagnosed. Analyzing different characteristic parameters, such as charring rate and temperature distribution, can identify the specific type of ablation and precisely pinpoint the cause of the failure. Material aging-induced ablation: when temperature gradient And carbonization rate When the carbonization rate is less than 3%, the ablation is characterized by a relatively uniform temperature distribution and a low degree of carbonization. The cause of this type of ablation is the gradual deterioration of the volume resistivity of the buffer layer semiconductor material during long-term operation, which leads to a uniform distribution of heat in the buffer layer, resulting in uniform heating and triggering the ablation phenomenon.

[0043] Gap discharge ablation: when the temperature gradient And carbonization rate At 3%, the buffer layer exhibits obvious localized high-temperature points and a high carbonization rate. The cause of this type of ablation is that, due to process or mechanical stress issues, the axial non-contact distance between the aluminum sheath and the buffer layer is too large, triggering localized gap discharge, generating extremely high temperatures, and thus exacerbating the ablation.

[0044] By establishing an early warning mechanism and fault cause diagnosis, the system achieves hierarchical management and risk quantification of the buffer layer ablation status. It can promptly identify potential risks, clarify maintenance strategies at different levels, and accurately pinpoint the ablation type and root cause by combining characteristic parameters. This provides a scientific basis for maintenance decisions and repairs, effectively improving fault prevention capabilities, reducing equipment operation risks, and ensuring the long-term safe and stable operation of high-voltage cables.

[0045] In step S5, a comprehensive assessment report is generated by integrating the preliminary ablation status analysis, risk assessment, and fault cause diagnosis. This report details the current ablation status of the buffer layer, the risk level at each stage, and the root causes of ablation. It comprehensively evaluates the equipment's operational health by combining data such as parameter change trends, temperature gradients, and carbonization rates. Furthermore, the report clearly identifies fault modes, such as the identification criteria and mechanism analysis for material aging-related ablation and gap discharge-related ablation, ensuring the accuracy and reliability of the diagnosis. This report not only provides a basis for subsequent decision-making but also supports the maintenance team in developing reasonable maintenance plans and optimizing operations. The generation of this report effectively improves maintenance efficiency, reduces potential risks, and ensures the equipment operates stably and safely in a long-term environment.

[0046] Example 2: To illustrate the technical method of this invention more specifically, this embodiment selects a 110kV XLPE cable sample, whose buffer layer material is semi-conductive resistive water tape with a volume resistivity of 1×10⁻⁶. 5Ω·m. The equipment used includes an infrared thermal imager, a pulse current generator, a high-frequency current sensor, a miniature negative pressure adsorption device, a dielectric loss tester, a laser particle size analyzer for powder particle size analysis, and a box-type muffle furnace. This embodiment uses... Figure 1 A preferred embodiment of a method for detecting and diagnosing the ablation of a high-voltage cable buffer layer includes the following steps: Step S1: Three-modal data acquisition steps; acquire temperature characteristic data, waveform spectrum data and powder performance data of the area to be evaluated; Step S2: Constructing a comprehensive evaluation model; Based on the collected temperature characteristic data, waveform spectrum data, and powder performance data, a comprehensive evaluation model for the high-voltage cable buffer layer is constructed. This comprehensive evaluation model includes components representing coupling strength, comprehensive state, and dynamic growth. A risk score is output through a normalized S-shaped function. This allows for a precise characterization of the entire cycle of buffer layer ablation, from microscopic degradation to macroscopic failure. Step S3: The steps for assessing the ablation status; based on the risk score output by the assessment model, identify and classify the ablation status; Step S4: Steps for generating operation and maintenance strategies; conduct a preliminary safety risk assessment of the ablation state, directly link the risk assessment results with operation and maintenance decisions, form an executable early warning mechanism, and accurately locate the cause of the failure; Step S5: The step of generating the evaluation result report; outputting the comprehensive evaluation results and the fault cause analysis report.

[0047] Step S1 includes the steps of collecting temperature characteristic data, collecting waveform spectrum data, and collecting powder performance data. Step S11, the step of collecting temperature characteristic data: A 3-meter section near the grounding box below the cable termination was scanned using a FLIR A31 infrared thermal imager, with a focus on the surface temperature of the aluminum sheath. Sampling was performed once per minute for 24 hours. The temperature range was 20°C to 120°C, with an accuracy of ±0.5°C. Temperature characteristic parameters, including average temperature, were extracted from the thermal images generated by the FLIR A31 infrared thermal imager. The temperature gradient, calculated based on the spacing between adjacent measuring points, is used to characterize the rate of temperature change per unit distance. Maximum temperature .

[0048] Step S12, the steps for acquiring waveform spectrum data: Connect the output of the pulse current generator to the cable conductor and inject a pulse signal with a center frequency of 500kHz. Acquire the reflected waveform using a Pearson 8595 current sensor clamped to the cable grounding wire for 5 minutes. Process the acquired waveform data to extract characteristic parameters, including the waveform distortion coefficient. This is used to represent the percentage difference in amplitude between the distorted waveform and the standard waveform; high-frequency component energy ratio. , used to reflect the proportion of energy in the frequency band above 1MHz to the total energy; and the number of partial discharge pulses N, representing the number of pulses occurring per minute.

[0049] Step S13, the step of collecting powder performance data: At the inspection port of the cable joint, approximately 0.5 grams of powder sample was collected from the surface of the buffer layer using a miniature negative pressure adsorption device. The collected powder sample underwent performance testing, specifically including: uniformly placing the powder sample in the electrodes of an HV-8000 dielectric loss tester and measuring the dielectric loss value. The particle size distribution of the powder was measured using a laser particle size analyzer to obtain the median particle size. A portion of the powder sample was placed in a crucible and calcined in a muffle furnace at 550°C for 3 hours. After cooling, the sample was weighed, and the carbonization rate K was calculated.

[0050] By collecting temperature, waveform, and powder data, the real-time status of the cable buffer layer can be accurately monitored, providing multi-dimensional data support for subsequent ablation analysis and evaluation. The accuracy and timeliness of this data provide a reliable basis for subsequent diagnosis, effectively improving the accuracy and response speed of fault detection.

[0051] In step S2: Based on the three-modal original feature data, an ablation comprehensive assessment model is constructed, and an ablation risk score is calculated. Starting from the multiphysics coupling mechanism, core components characterizing coupling strength, comprehensive index, and dynamic growth were constructed. Finally, the ablation risk score was obtained through a normalized S-shaped function. This enables accurate characterization of the entire ablation process of the buffer layer, from microscopic degradation to macroscopic failure. The calculation process for each core component and the ablation risk score is as follows: Step S21: Calculate the multimodal coupling strength factor. Steps: The multimodal coupling strength factor is used to quantify the nonlinear synergistic degradation effect among operating temperature, partial discharge, and material dielectric loss. Its construction is based on the theory of accelerated aging of insulating materials under combined electro-thermal stress. Specifically, increased temperature exacerbates partial discharge activity by reducing the carrier migration activation energy, while the active substances and Joule heat generated by the discharge further promote the destruction of the material's chemical structure and polarization loss, manifesting as increased dielectric loss. Temperature, partial discharge, and material dielectric loss constitute a positive feedback loop, significantly accelerating insulation degradation. The mathematical expression is: ; Parameter description: Reference temperature, usually selected as room temperature 293.15K; Temperature effect index, based on the thermal aging test data of XLPE insulated cables, is taken as 2.5; The apparent activation energy of the discharge process is taken as... ; : Ideal gas constant, taken as 8.314.

[0052] Step S22, calculate the thermo-electro-chemical composite index Steps: This method is used to comprehensively characterize the severe ablation state determined by localized overheating concentration effects, high-frequency discharge energy, and powder product characteristics. It integrates principles of heat conduction, electromagnetic wave energy deposition, and materials chemical analysis, aiming to capture characteristics that lead to irreversible degradation of insulation performance. The calculation formula is as follows: ; Parameter description: The thermal conductivity of the buffer layer material, for a semiconducting resistive water strip, is taken as... ; : Thermal diffusivity of the buffer layer, taken as ; The reference threshold for carbonization rate is 5%, based on the results of thermogravimetric analysis (TGA). The characteristic length affected by powder particle size is taken as 25 μm based on the particle packing and conductivity model.

[0053] Step S23, calculate the dynamic risk growth factor. Steps: The dynamic risk growth factor is used to describe the nonlinear acceleration phenomenon in the ablation process, with particular attention to the dynamic coupling between the frequency of discharge activity and the carbonization process of the material. The construction of the dynamic risk growth factor is based on the idea of ​​the autocatalytic process model in chemical reaction kinetics; specifically, the reaction products, namely conductive carbides, themselves change the electric field distribution, thereby accelerating the discharge activity and promoting further carbonization reactions. The calculation formula is: ; Parameter description: The critical frequency of discharge activity, based on phase-resolved partial discharge (PRPD) statistical analysis and Weibull distribution, is set at 50 times / min. The critical threshold for carbonization rate is set at 8%, based on the results of material scanning electron microscopy (SEM) and resistivity testing.

[0054] Step S24, calculate the ablation risk score. Steps: The ablation risk score is obtained by normalizing the output using the classic S-shaped growth curve model. The S-shaped growth curve model is widely used in systematic reliability assessment and failure prediction. It can smoothly map complex multi-factor coupled inputs to a defined risk level range, effectively avoiding abrupt changes near the threshold and ensuring the stability of the assessment results. The calculation formula is: ; in, The scaling factor is set to 0.15 based on historical fault data inversion and analysis.

[0055] By constructing a multimodal coupling strength factor, a thermo-electro-chemical comprehensive index, and a dynamic risk growth factor, the nonlinear synergistic effect in the ablation process can be accurately quantified. The ablation risk score Rscore is output through the S-shaped growth curve model, realizing the full-cycle accurate characterization of the ablation state of the high-voltage cable buffer layer. This not only provides a scientific basis for risk quantification and staged ablation judgment, improving the accuracy and reliability of ablation state identification, but also provides a reliable quantitative basis for operation and maintenance decisions.

[0056] In step S3: Based on ablation risk score Based on the numerical range, the ablation process of the buffer layer is initially divided into three stages, each corresponding to a typical range of characteristic parameters, to determine which ablation stage the cable buffer layer is in: Early ablation stage ( 20): At this stage, the local microstructure begins to deteriorate. Although the characteristic signals are weak, signs of ablation can be detected. Parameters such as temperature, partial discharge activity, and dielectric loss are all in the low range. Specifically, the buffer layer material begins to show initial thermal aging and slight hydrolysis, the waveform exhibits identifiable initial distortion, and the powder includes incompletely carbonized aluminum hydroxide. At this time, the typical parameter range is: <55℃, <0.15, <0.018, <2%.

[0057] Intermediate ablation stage (20 60): In this stage, the degradation process accelerates, hot spots form in localized areas, and stable discharges occur, resulting in significantly enhanced characteristic signals. Parameters show a decline in the electrical performance of the buffer layer, and discharge activity gradually increases. Specifically, the volume resistivity of the buffer layer decreases significantly, gap discharge activity becomes more active, and the powder consists of a mixture of carbonized particles and aluminum hydroxide. Typical parameter range: 55℃ 80℃, 0.15 0.45, 0.018 0.045, 2% 7%.

[0058] Late ablation stage ( At this stage, the buffer layer material has severely deteriorated, facing a high risk of thermal runaway and violent discharge. Insulation performance is severely reduced, and the material's thermal stability and electrical properties deteriorate significantly. Specifically, the buffer layer partially loses its function, the insulation layer faces direct threat, and the powder includes conductive carbides. Typical parameter ranges are: 80℃ 0.45, 0.045, 7%.

[0059] ablation risk score The ablation process of the buffer layer is divided into stages, enabling quantifiable identification of the entire process from microscopic degradation to thermal runaway. The parameter ranges for each stage are clearly defined, accurately reflecting the dynamic evolution characteristics of temperature, discharge, and carbonization rate. This provides a basis for early warning and condition assessment of the ablation process, helps to achieve graded diagnosis and trend prediction of fault risks, and improves the safety and reliability of high-voltage cable operation.

[0060] In step S4, a preliminary safety assessment of the ablation state is conducted, and the risk assessment results are combined with operation and maintenance decisions to form an executable early warning mechanism, thereby enabling timely identification and effective response to potential risks. Simultaneously, the operation and maintenance strategy also includes precise location of the fault causes to facilitate the development of targeted prevention and remediation measures.

[0061] This step includes generating an early warning mechanism and accurately locating the cause of the failure: Step S41, the steps for generating the early warning mechanism: Based on ablation risk score The values ​​are used to classify risk levels, and corresponding operation and maintenance strategies are formulated for each risk level.

[0062] exist Under a safety condition of <15, the buffer layer is stable, and no risk of ablation is detected. An operational strategy is generated to continue routine inspections and conduct periodic preventative tests.

[0063] When 15< is detected When the value is less than 35, it is defined as a state of alert, indicating early signs of ablation that require attention. The maintenance strategy is updated to: increase the monitoring frequency to once a week, use online monitoring devices to track the changing trends of characteristic parameters, and incorporate them into the recent maintenance plan.

[0064] When 35 A reading below 55 indicates a warning state, signifying that ablation has occurred and equipment reliability is declining. The maintenance strategy involves increasing monitoring frequency to once daily or implementing real-time monitoring, developing and implementing a detailed repair plan within one month, and reducing line load as necessary to mitigate risk.

[0065] when At 55°C, the situation was deemed dangerous. At this point, the ablation was severe, and serious accidents such as insulation breakdown could occur at any time. The maintenance strategy at this point was to immediately issue an emergency shutdown and maintenance order to ensure equipment safety.

[0066] Step S42, the steps to accurately locate the cause of the fault: By combining the relationships between characteristic parameters, the root cause of ablation can be diagnosed. Analyzing different characteristic parameters, such as charring rate and temperature distribution, can identify the specific type of ablation and precisely pinpoint the cause of the failure. Material aging-induced ablation: when temperature gradient And carbonization rate When the carbonization rate is less than 3%, the ablation is characterized by a relatively uniform temperature distribution and a low degree of carbonization. The cause of this type of ablation is the gradual deterioration of the volume resistivity of the buffer layer semiconductor material during long-term operation, which leads to a uniform distribution of heat in the buffer layer, resulting in uniform heating and triggering the ablation phenomenon.

[0067] Gap discharge ablation: when the temperature gradient And carbonization rate At 3%, the buffer layer exhibits obvious localized high-temperature points and a high carbonization rate. The cause of this type of ablation is that, due to process or mechanical stress issues, the axial non-contact distance between the aluminum sheath and the buffer layer is too large, triggering localized gap discharge, generating extremely high temperatures, and thus exacerbating the ablation.

[0068] By establishing an early warning mechanism and fault cause diagnosis, the system achieves hierarchical management and risk quantification of the buffer layer ablation status. It can promptly identify potential risks, clarify maintenance strategies at different levels, and accurately pinpoint the ablation type and root cause by combining characteristic parameters. This provides a scientific basis for maintenance decisions and repairs, effectively improving fault prevention capabilities, reducing equipment operation risks, and ensuring the long-term safe and stable operation of high-voltage cables.

[0069] In step S5, a comprehensive assessment report is generated by integrating the preliminary ablation status analysis, risk assessment, and fault cause diagnosis. This report details the current ablation status of the buffer layer, the risk level at each stage, and the root causes of ablation. It comprehensively evaluates the equipment's operational health by combining data such as parameter change trends, temperature gradients, and carbonization rates. Furthermore, the report clearly identifies fault modes, such as the identification criteria and mechanism analysis for material aging-related ablation and gap discharge-related ablation, ensuring the accuracy and reliability of the diagnosis. This report not only provides a basis for subsequent decision-making but also supports the maintenance team in developing reasonable maintenance plans and optimizing operations. The generation of this report effectively improves maintenance efficiency, reduces potential risks, and ensures the equipment operates stably and safely in a long-term environment.

[0070] Example 3: like Figure 2 As shown, this embodiment provides a detection and diagnosis system for the ablation of the buffer layer of a high-voltage cable, comprising: The three-modal data acquisition module 1 is used to acquire temperature characteristic data, waveform spectrum data, and powder performance data of the area to be evaluated. Temperature data is acquired using an infrared thermal imager or fiber optic temperature sensor. Waveform spectrum data is obtained by injecting a pulse signal from a pulse current generator into the cable conductor and acquiring the reflected waveform using a high-frequency current sensor. A miniature negative pressure adsorption device is used to collect powder samples generated during the ablation process, and the samples are measured using a dielectric loss tester and a laser particle size analyzer. This module enables simultaneous acquisition of temperature, waveform, and powder information, ensuring comprehensive acquisition of the cable buffer layer's condition data from multiple perspectives. The combined acquisition of three-modal data provides multi-dimensional evidence for subsequent condition analysis, ensuring the accuracy and comprehensiveness of the evaluation process.

[0071] The comprehensive evaluation model construction module 2, based on temperature characteristic data, waveform spectrum data, and powder performance data acquired from the three-modal data acquisition module 1, constructs an ablation comprehensive evaluation model and performs preliminary identification of the ablation state through nonlinear analysis. By integrating information such as temperature characteristic data, waveform spectrum data, and powder performance data, core components characterizing coupling strength, overall state, and dynamic growth are constructed. Finally, an ablation risk score is output through a normalized S-shaped function to achieve accurate characterization of the entire cycle of buffer layer ablation, from microscopic degradation to macroscopic failure. Through deep fusion and processing of comprehensive multimodal data, the information bias caused by a single data source is overcome, improving the accuracy of ablation state identification and dynamic monitoring capabilities.

[0072] The ablation status grading module 3 classifies the ablation status of the cable buffer layer based on the ablation risk score output by the comprehensive evaluation model. By analyzing the ablation risk score, the ablation status of the buffer layer is divided into three stages: early ablation stage, mid-stage ablation stage, and late ablation stage, with each level corresponding to a typical range of characteristic parameters. Through the grading evaluation of this module, the entire process from early microscopic degradation to late thermal runaway can be monitored, helping to identify the ablation status in a timely manner and providing a reliable basis for subsequent operation and maintenance and safety decisions.

[0073] The operation and maintenance strategy generation module 4 directly links the ablation risk assessment results with operation and maintenance decisions, generating executable early warning mechanisms and response strategies. Based on the assessed ablation level and ablation risk score, the module automatically formulates and adjusts the operation and maintenance strategy: in a safe state, routine inspections are performed; in a watchful or warning state, monitoring frequency is increased and specific inspections are conducted; in a dangerous state, immediate shutdown and maintenance are recommended. This module can transform assessment results into specific and highly executable operation and maintenance measures, reducing human decision-making errors and ensuring the safety and stability of cables during use.

[0074] The assessment report output module 5 generates a comprehensive assessment result report and a fault cause analysis report. The report content includes the classification of the ablation state, detailed risk assessment results, analysis of potential fault causes, and recommended remedial measures. The report provides a scientific basis for subsequent maintenance decisions and helps maintenance personnel develop reasonable inspection and repair plans. After generation, the report can be automatically transmitted through an interface with the maintenance management system, providing operators with real-time and accurate decision support. By generating structured reports, maintenance personnel can effectively make accurate maintenance decisions, improve work efficiency, reduce fault handling time, and ensure the long-term operation of cables.

[0075] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The methods disclosed in the embodiments are described simply because they correspond to the systems disclosed in the embodiments; relevant details can be found in the method section.

[0076] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0077] In the embodiments provided by this invention, it should be understood that the disclosed systems, methods, and approaches can be implemented in other ways. For example, the system embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between systems or units may be electrical, mechanical, or other forms.

[0078] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0079] In addition, the functional modules in the various embodiments of the present invention can be integrated into one processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit.

[0080] Similarly, in the various embodiments of the present invention, each processing unit can be integrated into a functional module, or each processing unit can exist physically, or two or more processing units can be integrated into a functional module.

[0081] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0082] 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. Without further limitations, 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.

[0083] The above-disclosed embodiments are merely preferred embodiments of the present invention, but the present invention is not limited thereto. Any non-creative variations that can be conceived by those skilled in the art, as well as any improvements and modifications made without departing from the principles of the present invention, should fall within the protection scope of the present invention.

Claims

1. A method for detecting and diagnosing the ablation of the buffer layer in a high-voltage cable, characterized in that, Includes the following steps: Step S1: Three-modal data acquisition steps; acquire temperature characteristic data, waveform spectrum data and powder performance data of the area to be evaluated; Step S2: Constructing a comprehensive evaluation model; Based on the collected temperature characteristic data, waveform spectrum data, and powder performance data, a comprehensive evaluation model for the high-voltage cable buffer layer is constructed. This comprehensive evaluation model includes components representing coupling strength, comprehensive state, and dynamic growth. A risk score is output through a normalized S-shaped function. This allows for a precise characterization of the entire cycle of buffer layer ablation, from microscopic degradation to macroscopic failure. Step S3: The steps for assessing the ablation status; based on the risk score output by the assessment model, identify and classify the ablation status; Step S4: Steps for generating operation and maintenance strategies; A preliminary safety risk assessment of the ablation state is conducted, and the risk assessment results are directly linked to operation and maintenance decisions to form an executable early warning mechanism and accurately locate the cause of the failure. Step S5: The step of generating the evaluation result report; Output a comprehensive evaluation result and a fault cause analysis report.

2. The method for detecting and diagnosing the ablation of the buffer layer of a high-voltage cable according to claim 1, characterized in that, Step S1 includes the steps of collecting temperature characteristic data, collecting waveform spectrum data, and collecting powder performance data. Step S11, the step of collecting temperature characteristic data: Continuous temperature monitoring is performed on the surface of the cable buffer layer or key areas using an infrared thermal imager or fiber optic temperature sensor. The sampling frequency is once per minute, the temperature range is 20°C to 120°C, and the accuracy is ±0.5°C. Temperature characteristic parameters, including average temperature, are extracted. Temperature gradient used to characterize the rate of temperature change per unit distance Maximum temperature ; Step S12, the steps for acquiring waveform spectrum data: A broadband pulse signal is injected into the cable conductor using the pulsed current method, and the reflected waveform is acquired using a high-frequency current sensor. Based on the acquired waveform data, characteristic parameters, including the waveform distortion coefficient, are extracted. High-frequency component energy ratio And the number of partial discharge pulses N; Step S13, the step of collecting powder performance data: At cable terminations, intermediate joint inspection ports, or other locations accessible to the buffer layer, a miniature negative pressure adsorption device is used to collect powder samples generated during the ablation process. The collected powder samples are then subjected to performance testing, including measuring the dielectric loss value of the powder samples. Determine the particle size distribution of powder samples. ; And calculate the carbonization rate of the powder. .

3. A method for detecting and diagnosing the ablation of a high-voltage cable buffer layer according to claim 1 or 2, characterized in that, Temperature characteristic data can be collected using the FLIR A315 infrared thermal imager, which can be flexibly installed in any area that needs to be monitored to detect temperature differences in real time and visualize the temperature distribution. Fiber optic temperature sensors, such as the FBG-4000, can also be used for temperature monitoring. These sensors acquire temperature data using fiber optic Bragg grating technology.

4. The method for detecting and diagnosing the ablation of the buffer layer of a high-voltage cable according to claim 3, characterized in that, In step S2: Based on the three-modal original feature data, an ablation comprehensive assessment model is constructed, and an ablation risk score is calculated. Starting from the multiphysics coupling mechanism, core components characterizing coupling strength, integrated state and dynamic growth are constructed respectively, and finally the risk score is output through a normalized S-shaped function.

5. The method for detecting and diagnosing the ablation of the buffer layer of a high-voltage cable according to claim 4, characterized in that, In step S2, the core components characterizing coupling strength, comprehensive index, and dynamic growth, as well as the ablation risk score, are described. The calculation process is as follows: Step S21: Calculate the multimodal coupling strength factor. Steps: The multimodal coupling strength factor is used to quantify the nonlinear synergistic degradation effect among operating temperature, partial discharge, and material dielectric loss. Its mathematical expression is: ； Step S22, calculate the thermo-electro-chemical composite index Steps: The formula used to comprehensively characterize the severe ablation state determined by the localized overheating concentration effect, high-frequency discharge energy, and powder product characteristics is as follows: ； Step S23, calculate the dynamic risk growth factor. Steps: The dynamic risk growth factor is used to describe the nonlinear acceleration phenomenon in the ablation process, with particular attention to the dynamic coupling between the frequency of discharge activity and the carbonization process of the material. The calculation formula is: ； Step S24, calculate the ablation risk score. Steps: The final risk score is obtained by normalizing the output using the classic S-shaped growth curve model. The calculation formula is: 。 6. The method for detecting and diagnosing the ablation of the buffer layer of a high-voltage cable according to claim 5, characterized in that, In step S3: based on the ablation risk score Based on the numerical range, the buffer layer ablation process can be preliminarily divided into three stages, each corresponding to a typical range of characteristic parameters: Early ablation stage: The buffer layer material begins to show initial thermal aging and slight hydrolysis, and the waveform exhibits identifiable initial distortion. The powder includes incompletely carbonized aluminum hydroxide. At this stage, the typical parameter range is: <55℃, <0.15, <0.018, <2%; Mid-stage ablation: The volume resistivity of the buffer layer decreases significantly, and interstitial discharge activity becomes more active. The powder consists of a mixture of carbonized particles and aluminum hydroxide. Typical parameter range: 55℃ 80℃, 0.15 0.45，0.018 0.045，2% 7%； Late ablation stage: The buffer layer partially loses its function, the insulation layer faces direct threat, and the powder includes conductive carbides. Typical parameter ranges are: 80℃ 0.45, 0.045, 7%.

7. The method for detecting and diagnosing the ablation of the buffer layer of a high-voltage cable according to claim 6, characterized in that, In step S4: a preliminary safety assessment of the ablation state is conducted, and the risk assessment results are combined with operation and maintenance decisions to form an executable early warning mechanism. Simultaneously, the operation and maintenance strategy also includes the precise location of the fault cause. This step includes the steps of generating the early warning mechanism and the precise location of the fault cause. Step S41, the steps for generating the early warning mechanism: Based on ablation risk score The values ​​are used to classify risk levels, and corresponding operation and maintenance strategies are formulated for each risk level: exist Under a safety condition of <15, the buffer layer is stable and no risk of ablation is found; an operation and maintenance strategy is generated to continue to perform routine inspections and conduct periodic preventive tests. When 15< is detected When the value is less than 35, it is defined as a state of alert, indicating that early signs of ablation have been detected and require attention. The operation and maintenance strategy is updated to: increase the monitoring frequency to once a week, use online monitoring devices to track the changing trends of characteristic parameters, and incorporate them into the recent maintenance plan. When 35 If the value is less than 55, it is considered a warning state, indicating that burning has occurred and the equipment reliability has begun to decline. The maintenance strategy is to increase the monitoring frequency to once a day or to perform real-time monitoring, and to develop and implement a detailed maintenance plan within one month to reduce the line load. when At 55 minutes past the hour, the situation is deemed dangerous, as severe ablation could occur at any time, potentially leading to insulation breakdown. The maintenance strategy at this point is to immediately issue an emergency shutdown and repair order to ensure equipment safety. Step S42, the steps to accurately locate the cause of the fault: By combining the relationships between characteristic parameters, the root cause of ablation can be diagnosed. By analyzing different characteristic parameters, the specific type of ablation can be identified and the cause of the failure can be precisely located. Material aging-induced ablation: when temperature gradient And carbonization rate When the temperature is less than 3%, the ablation is characterized by a relatively uniform temperature distribution and a low degree of carbonization. The cause of this type of ablation is that the volume resistivity of the buffer layer semiconductor material gradually deteriorates during long-term operation, resulting in uniform heating and triggering the ablation phenomenon. Gap discharge ablation: when the temperature gradient And carbonization rate At 3%, the buffer layer exhibits obvious local high-temperature points and a high carbonization rate. The cause of this type of ablation is that the axial non-contact distance between the aluminum sheath and the buffer layer is too large, which triggers local gap discharge, generates extremely high temperatures, and exacerbates the ablation.

8. The method for detecting and diagnosing the ablation of the buffer layer of a high-voltage cable according to claim 7, characterized in that, In step S5: By comprehensively analyzing the ablation status, risk assessment and fault cause diagnosis in the early stage, a complete assessment result report is output.

9. A detection and diagnostic system for the ablation of the buffer layer in high-voltage cables, characterized in that, include: Three-modal data acquisition module (1), comprehensive evaluation model construction module (2), ablation state classification module (3), operation and maintenance strategy generation module (4), evaluation report output module (5); The three-modal data acquisition module (1) is used to acquire temperature characteristic data, waveform spectrum data and powder performance data of the area to be evaluated; The comprehensive evaluation model construction module (2) constructs an ablation comprehensive evaluation model based on the collected data to preliminarily identify the ablation state of the buffer layer; The ablation status classification module (3) classifies and identifies the ablation status based on the ablation risk score output by the comprehensive evaluation model. The operation and maintenance strategy generation module (4) directly links the risk assessment results with the operation and maintenance decisions, and generates an executable early warning mechanism and response strategy; The assessment report output module (5) is used to generate a comprehensive assessment result and a fault cause analysis report.

10. The detection and diagnosis system for high-voltage cable buffer layer ablation according to claim 9, characterized in that, The three-modal data acquisition module (1) is used to acquire temperature characteristic data, waveform spectrum data and powder performance data of the area to be evaluated; wherein, the temperature data is acquired by an infrared thermal imager or a fiber optic temperature sensor, the waveform spectrum data is injected into the cable conductor by a pulse signal output by a pulse current generator, and the reflected waveform is acquired by a high-frequency current sensor; a micro negative pressure adsorption device is used to collect powder samples generated during the ablation process, and the samples are measured by a dielectric loss tester and a laser particle size analyzer; The comprehensive evaluation model construction module (2) constructs an ablation comprehensive evaluation model based on the temperature characteristic data, waveform spectrum data and powder performance data obtained from the three-modal data acquisition module (1), and performs preliminary identification of the ablation state through nonlinear analysis; by integrating the temperature characteristic data, waveform spectrum data and powder performance data, it constructs core components that characterize the coupling strength, comprehensive state and dynamic growth, and finally outputs the ablation risk score through a normalized S-shaped function; The ablation status classification module (3) classifies and identifies the ablation status of the cable buffer layer based on the ablation risk score output by the comprehensive evaluation model construction module (2). By analyzing the ablation risk score, the ablation status of the buffer layer is divided into three stages: early ablation stage, mid-term ablation stage, and late ablation stage. Each level corresponds to a typical characteristic parameter range. The operation and maintenance strategy generation module (4) directly links the ablation risk assessment results with the operation and maintenance decisions, and generates an executable early warning mechanism and response strategy. Based on the assessed ablation level and ablation risk score, the module automatically formulates and adjusts the operation and maintenance strategy: in a safe state, routine inspections are performed; in a state of alert or warning, the monitoring frequency is increased and specific inspections are carried out; in a dangerous state, it is recommended to immediately shut down the machine for maintenance. The assessment report output module (5) is used to generate a comprehensive assessment result report and a fault cause analysis report. The report content includes the classification of ablation status, detailed results of risk assessment, analysis of potential fault causes, and recommended repair measures.

Images