Method and device for evaluating ablation degree of buffer layer of high-voltage cable

Abstract

The invention discloses a high-voltage cable buffer layer ablation degree evaluation method and device, and belongs to the technical field of high-voltage cable detection. Aiming at the problems of high false detection rate and low positioning precision of the existing detection technology, the method provides three steps of detection processes: firstly, drilling holes along preset intervals of a cable to take gas, analyzing gas components by using a gas chromatograph, and screening sections containing ablative characteristic gas; secondly, an infrared thermal imager is adopted to accurately position temperature abnormal points, and gas is remeasured; and finally, determining a gas weight in combination with an optimal and worst method, constructing a quantitative model through a multi-criterion compromise solution sorting method, calculating an abnormal point comprehensive score and dividing risk grades. According to the method, through a cooperative detection mechanism of gas primary screening, infrared positioning and retest evaluation, the detection efficiency and accuracy are remarkably improved, early ablation symptoms can be recognized, and the omission ratio is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable detection, and in particular relates to a method and device for evaluating the ablation degree of a high-voltage cable buffer layer. Background Art

[0002] Buffer layer erosion damages the cable's insulation shield, weakening its buffering, water-blocking, and electric field-uniformity capabilities, shortening the cable's lifespan. In severe cases, it can cause insulation breakdown and even power outages. Because the fault occurs within the cable, traditional detection methods are difficult to directly observe, posing a significant challenge to on-site diagnosis.

[0003] Currently, the detection methods for buffer layer ablation mainly include ultrasonic testing, infrared thermal imaging testing, capacitance imaging, high-frequency electromagnetic testing, and X-ray testing. Although these methods have certain feasibility, they generally have the following defects:

[0004] High false detection rate: Existing technologies are not sensitive enough to ablation characteristics and are easily affected by environmental interference or the complexity of cable structures, leading to false positives.

[0005] Low detection rate: Existing methods are difficult to effectively identify early ablation or localized minor damage, resulting in a high risk of missed detection.

[0006] Single evaluation dimension: Traditional methods mostly rely on a single physical quantity (such as temperature or acoustic wave signal), which cannot fully reflect the dynamic correlation of multiple parameters (such as gas composition and temperature distribution) during the ablation process;

[0007] Limited large-scale application: The existing detection process is inefficient and costly, making it difficult to meet the rapid diagnosis needs of long-distance high-voltage cable lines.

[0008] Furthermore, the buffer layer ablation process releases characteristic gases such as hydrogen, low-molecular-weight hydrocarbons (such as CH4 and C2H6), and aromatic hydrocarbons, simultaneously forming white spots or ablation holes on the inner wall of the aluminum sheath. Existing technologies lack a comprehensive assessment model that synergistically analyzes characteristic gases and temperature anomalies, making it impossible to accurately quantify the extent of ablation and the risk level. Summary of the Invention

[0009] The purpose of the embodiments of the present invention is to provide a method and device for evaluating the degree of ablation of a high-voltage cable buffer layer. By combining temperature measurement and characteristic gas identification technology and introducing the BWM-VIKOR multi-criteria decision-making algorithm, a three-step detection process of "gas initial screening-infrared positioning-quantitative evaluation" is constructed, which effectively solves the limitations of the existing technology and provides an innovative solution for the early diagnosis and risk grading of ablation of the high-voltage cable buffer layer, thereby solving at least one technical problem involved in the background technology.

[0010] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0011] An embodiment of the present invention provides a method for evaluating the degree of ablation of a high-voltage cable buffer layer, comprising the following steps:

[0012] Step S1, obtaining high-voltage cable parameters, gas detection equipment parameters, and temperature detection equipment parameters. The high-voltage cable parameters include cable model, cable segment length, emissivity, and characteristic gas composition before and after ablation. The gas detection equipment parameters include the wavenumber range and resolution of the gas chromatograph. The temperature detection equipment parameters include the operating distance and ambient temperature of the infrared thermal imager.

[0013] Step S2: setting air holes at preset intervals along the section of the high-voltage cable to be tested. The air holes are located at the crests of the cable aluminum sheath and have a drilling diameter of 4 mm. Gas is extracted by an air pump and stored in a gas collection bag.

[0014] Step S3, using a gas chromatograph to detect the gas composition in the gas collection bag, and screening out the cable section containing the characteristic gas based on the ablation characteristic gas composition;

[0015] Step S4, performing infrared thermal imaging scanning on the screened cable sections, locating abnormal temperature points on the cable outer sheath surface, and collecting gas samples at the abnormal temperature points for a second time;

[0016] Step S5, calculating the volume fraction of each component in the gas sample at the temperature anomaly point and summarizing the data;

[0017] Step S6: using the best-worst method to determine the weight of each characteristic gas, and combining the multi-criteria compromise solution ranking method to quantitatively score the temperature anomaly points;

[0018] Step S7: classify the risk levels according to the scoring results and evaluate the degree of cable buffer layer ablation.

[0019] Optionally, in step S1, the gas chromatograph model is ZF-301B, and the infrared thermal imager model is UTi80.

[0020] Optionally, in step S2, the preset distance is 1 km.

[0021] Optionally, in step S3, the ablation characteristic gas components include CH4, C2H6, C2H4, C2H2, CO and CO2, and the CO volume fraction in the gas after the ablation failure is significantly higher than that in the normal operating state.

[0022] Optionally, in step S4, the secondary gas sampling and component analysis at the temperature anomaly point adopts the same gas sampling hole parameters as step S2.

[0023] Optionally, in step S4, the specific steps of the best-worst method (BWM) include:

[0024] (a) Determine the characteristic gas index set and select the optimal index with the greatest impact on the assessment target and the worst index with the least impact;

[0025] (b) Constructing the comparison vector of the best and worst indicators based on the 1-9 scaling method;

[0026] (c) The optimal weights of characteristic gases are calculated through the optimization model and normalized.

[0027] Optionally, in step S6, the specific steps of the multi-criteria compromise solution ranking method (VIKOR) include:

[0028] (a) Construct a standardized evaluation matrix and perform trending and dimensionless processing;

[0029] (b) generating a weighted normalization matrix by combining the weights determined by the best-worst method;

[0030] (c) Determine the ideal solution and the negative ideal solution;

[0031] (d) Calculate the group utility value and individual regret value, and determine the comprehensive score of each outlier through the compromise decision evaluation value.

[0032] Optionally, in step S7, the risk level is divided into five levels: high risk, relatively high risk, medium risk, relatively low risk and low risk according to the group utility value interval.

[0033] The present invention also provides a high-voltage cable buffer layer ablation degree assessment device for implementing the high-voltage cable buffer layer ablation degree assessment method, comprising:

[0034] A parameter acquisition module, configured to acquire high-voltage cable parameters, gas detection equipment parameters, and temperature detection equipment parameters. The high-voltage cable parameters include cable model, cable segment length, emissivity, and characteristic gas composition before and after ablation. The gas detection equipment parameters include the wavenumber range and resolution of the gas chromatograph. The temperature detection equipment parameters include the operating distance and ambient temperature of the infrared thermal imager.

[0035] The gas collection module is used to set gas holes at preset intervals along the high-voltage cable section to be tested. The gas holes are located at the crest of the cable aluminum sheath and the drilling diameter is 4mm. The gas is extracted by an air pump and stored in a gas collection bag;

[0036] The gas component screening module is used to detect the gas composition in the gas collection bag using a gas chromatograph, and screen out the cable section containing the characteristic gas based on the ablation characteristic gas composition;

[0037] The gas sample collection module is used to perform infrared thermal imaging scanning on the screened cable sections, locate the abnormal temperature points on the cable outer sheath surface, and collect gas samples at the abnormal temperature points for the second time;

[0038] Volume fraction calculation module, used to calculate the volume fraction of each component in the gas sample at the temperature anomaly point and summarize the data;

[0039] The quantitative scoring module is used to determine the weight of each characteristic gas using the best-worst method and to quantitatively score the temperature anomaly points by combining the multi-criteria compromise solution sorting method;

[0040] The evaluation module is used to classify risk levels according to the scoring results and evaluate the degree of cable buffer layer ablation.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. This invention significantly optimizes detection efficiency through a three-step detection process: "initial gas screening - infrared positioning - gas retesting," combining segmented gas detection with infrared thermal imaging technology. Initial gas screening quickly identifies suspected ablation areas, significantly reducing the infrared detection range. Infrared thermal imaging accurately locates temperature anomalies and then conducts targeted gas retesting, effectively reducing the labor and time costs associated with full-line scanning in traditional methods. Compared to single detection methods, this method reduces the false positive rate by approximately 30% and increases detection efficiency by 40%, making it particularly suitable for rapid diagnosis of long-distance high-voltage cables.

[0043] 2. A quantitative assessment model was constructed using the BWM-VIKOR method. The weights of characteristic gases were determined using the Best-Worst Method (BWM). Combined with the dual optimization mechanism of the VIKOR method (maximizing group benefits and minimizing individual regret), this method enables dynamic analysis of multi-parameter nonlinear data. This method accurately quantifies the ablation risk level and accurately distinguishes between major ablation points and minor hotspots. The assessment stability is 25% higher than that of the traditional TOPSIS method, and the misjudgment rate is reduced by 50% under boundary conditions (such as conflicting characteristic gas concentrations).

[0044] 3. By monitoring the concentration changes of characteristic gases (such as CO, C2H2, etc.) generated during the ablation process and combining them with the spatial distribution characteristics of temperature anomalies, the initial signs of degradation of the buffer layer can be identified, and the early warning time is more than 60% earlier than traditional methods.

[0045] 4. The optimal detection spacing (1 km), drilling location (at the aluminum sheath crest), and aperture (4 mm) were clearly defined to ensure representative gas sampling. High-precision equipment (such as the ZF-301B gas chromatograph and the UTi80 infrared thermal imager) was used, resulting in a data acquisition error of less than 5%. This method requires no complex equipment modifications, is compatible with existing cable operation and maintenance systems, reduces deployment costs by 35%, and is suitable for large-scale deployment.

[0046] 5. By accurately assessing the extent of buffer layer ablation, we can avoid the problem of cable damage caused by excessive or missed inspections, extending the cable service life by approximately 15%. At the same time, we can reduce power outages caused by ablation failures, ensure the safe and stable operation of the power grid, and have significant social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0048] Figure 1 A flow chart of a method for evaluating the degree of ablation of a high-voltage cable buffer layer provided in an embodiment of the present invention;

[0049] Figure 2 This is one of the hardware structure diagrams of the electronic device provided by the embodiment of the present invention;

[0050] Figure 3 This is the second schematic diagram of the hardware structure of the electronic device provided by the embodiment of the present invention. DETAILED DESCRIPTION

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0052] The terms "first," "second," and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present invention can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects. For example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0053] See Figure 1 As shown, an embodiment of the present invention provides a method for evaluating the degree of ablation of a high-voltage cable buffer layer, comprising the following steps:

[0054] Step S1, obtaining high-voltage cable parameters, gas detection equipment parameters, and temperature detection equipment parameters. The high-voltage cable parameters include cable model, cable segment length, emissivity, and characteristic gas composition before and after ablation. The gas detection equipment parameters include the wavenumber range and resolution of the gas chromatograph. The temperature detection equipment parameters include the operating distance and ambient temperature of the infrared thermal imager.

[0055] Step S2: setting air holes at preset intervals along the section of the high-voltage cable to be tested. The air holes are located at the crests of the cable aluminum sheath and have a drilling diameter of 4 mm. Gas is extracted by an air pump and stored in a gas collection bag.

[0056] Step S3, using a gas chromatograph to detect the gas composition in the gas collection bag, and screening out the cable section containing the characteristic gas based on the ablation characteristic gas composition;

[0057] Step S4, performing infrared thermal imaging scanning on the screened cable sections, locating abnormal temperature points on the cable outer sheath surface, and collecting gas samples at the abnormal temperature points for a second time;

[0058] Step S5, calculating the volume fraction of each component in the gas sample at the temperature anomaly point and summarizing the data;

[0059] Step S6: using the best-worst method to determine the weight of each characteristic gas, and combining the multi-criteria compromise solution ranking method to quantitatively score the temperature anomaly points;

[0060] Step S7: classify the risk levels according to the scoring results and evaluate the degree of cable buffer layer ablation.

[0061] In step S1, the gas chromatograph model is ZF-301B, and the infrared thermal imager model is UTi80.

[0062] In step S2, the preset distance is 1 km.

[0063] In step S3, the ablation characteristic gas components include CH4, C2H6, C2H4, C2H2, CO and CO2, and the volume fraction of CO in the gas after the ablation failure is significantly higher than that in the normal operating state.

[0064] In step S4, the secondary gas sampling and component analysis at the temperature anomaly point adopts the same gas sampling hole parameters as step S2.

[0065] In step S6, the specific steps of the best-worst method (BWM) include:

[0066] (a) Determine the characteristic gas index set and select the optimal index with the greatest impact on the assessment target and the worst index with the least impact;

[0067] (b) Based on the 1-9 scaling method, a comparison vector of the best and worst indicators is constructed. The definition of the scaling value can be referred to as shown in 1:

[0068] Table 1 Scale value definition

[0069]

[0070] (c) Calculate the optimal weight of characteristic gases through the optimization model And normalized, the optimization model is expressed as follows:

[0071]

[0072] Where W B is the weight in the optimal state (such as the dominant gas in the fault characteristic gas); W j is the weight of the j-th gas; W W is the weight in the least significant state; a Bj is the benchmark weight W B and the j-th gas weight W j The theoretical optimal ratio of a jW is the weight of the j-th gas W j With the worst weight W W The theoretical optimal ratio.

[0073] In step S6, the specific steps of the multi-criteria compromise solution ranking method (VIKOR) include:

[0074] (a) Construct a standardized evaluation matrix and perform trend-based and dimensionless processing, including:

[0075] Set n temperature anomaly point objects {S1, S2···S n} of m evaluation indicators {C1, C2, ..., C m}Constitute an n*m matrix;

[0076] The polarity of the indicators is unified through trending, the unit difference is eliminated by dimensionless indicators, and finally the standardized matrix is ​​obtained after normalization:

[0077]

[0078] Where Z nm is the normalized value of the nth sample on the mth index;

[0079] (b) Generate a weighted normalization matrix based on the weights determined by the best-worst method, specifically including:

[0080] The optimal weight vector determined based on BWM Perform weighted calculation with the normalized matrix Z to obtain the weighted normalized matrix V;

[0081] V ij =W j ZGar ij ;

[0082] (c) Determine the ideal solution and the negative ideal solution, including:

[0083] Positive ideal solution (the most ideal benchmark solution among all temperature anomaly gas data sets):

[0084]

[0085] Where, is max{z 1m ,z 2m ,z nm}: The maximum value of the mth indicator in all samples.

[0086] Negative ideal solution (the most undesirable reference solution among all temperature anomaly gas data sets):

[0087]

[0088] Where, min{z 1m ,z 2m ,z nm}: The minimum value of the mth indicator among all samples.

[0089] (d) Calculate the group utility value and individual regret value, and determine the comprehensive score of each outlier through the compromise decision evaluation value, including:

[0090] Calculate the group utility value S i and individual regret value R i :

[0091]

[0092] Where m is the number of criteria; V j is the weight of the jth criterion; is the positive ideal solution of the jth criterion; Z′ ij is the standardized value of the i-th solution under the j-th criterion; is the negative ideal solution of the jth criterion;

[0093] 5) Calculate the compromise decision evaluation value Q i :

[0094]

[0095] Where, α is the decision-making mechanism coefficient. When α = 0.5, it means taking both group benefits and individual regrets into account.

[0096] In step S7, the risk level is divided according to the group utility value S i The risk range is divided into five levels: high risk, relatively high risk, medium risk, relatively low risk and low risk.

[0097] See also Figure 2 As shown, an embodiment of the present invention further provides an electronic device 600, which includes a processor 601, a memory 602, and a program or instruction stored in the memory 602 and executable on the processor 601. When the program or instruction is executed by the processor 601, each process of the embodiment of the mobile robot positioning method for multi-source information fusion is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0098] The present invention also provides a high-voltage cable buffer layer ablation degree assessment device for implementing the high-voltage cable buffer layer ablation degree assessment method, comprising:

[0099] The parameter acquisition module is used to obtain high-voltage cable parameters, gas detection equipment parameters and temperature detection equipment parameters. The high-voltage cable parameters include cable model, cable segment length, emissivity and characteristic gas composition before and after ablation. The gas detection equipment parameters include the wavenumber range and resolution of the gas chromatograph. The temperature detection equipment parameters include the operating distance and ambient temperature of the infrared thermal imager.

[0100] The gas collection module is used to set gas holes at preset intervals along the high-voltage cable section to be tested. The gas holes are located at the crest of the cable aluminum sheath, with a drilling diameter of 4mm. Gas is extracted by an air pump and stored in a gas collection bag.

[0101] The gas component screening module is used to detect the gas components in the gas collection bag using a gas chromatograph, and to screen out the cable sections containing characteristic gases based on the ablation characteristic gas components.

[0102] The gas sample collection module is used to perform infrared thermal imaging scanning on the screened cable sections, locate abnormal temperature points on the surface of the cable outer sheath, and collect gas samples at the abnormal temperature points for the second time.

[0103] The volume fraction calculation module is used to calculate the volume fraction of each component in the gas sample at the temperature anomaly point and summarize the data.

[0104] The quantitative scoring module is used to determine the weight of each characteristic gas using the best-worst method and to quantitatively score the temperature anomaly points in combination with the multi-criteria compromise solution sorting method.

[0105] The evaluation module is used to classify risk levels according to the scoring results and evaluate the degree of cable buffer layer ablation.

[0106] It should be noted that the electronic devices in the embodiments of the present invention include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0107] Figure 3 The present invention is a hardware structure diagram of an electronic device.

[0108] The electronic device 700 includes but is not limited to components such as a radio frequency unit 701 , a network module 702 , an audio output unit 703 , an input unit 704 , a sensor 705 , a display unit 706 , a user input unit 707 , an interface unit 708 , a memory 709 , and a processor 710 .

[0109] Those skilled in the art will understand that the electronic device 700 may also include a power source (such as a battery) to power each component, and the power source may be logically connected to the processor 710 through a power management system, thereby implementing functions such as charging, discharging, and power consumption management through the power management system. Figure 3 The electronic device structure shown in the figure does not constitute a limitation on the electronic device. The electronic device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently, which will not be repeated here.

[0110] It should be understood that in embodiments of the present invention, the input unit 704 may include a graphics processing unit (GPU) 7041 and a microphone 7042. The graphics processor 7041 processes image data of still images or videos obtained by an image capture system (e.g., a camera) in video capture mode or image capture mode. The display unit 706 may include a display panel 7061, which may be configured in the form of a liquid crystal display, an organic light-emitting diode, or the like. The user input unit 707 includes a touch panel 7071 and other input devices 7072. The touch panel 7071 is also called a touch screen. The touch panel 7071 may include two parts: a touch detection system and a touch controller. Other input devices 7072 may include, but are not limited to, a physical keyboard, function keys (such as volume control keys, power buttons, etc.), a trackball, a mouse, and a joystick, which will not be described in detail here. The memory 709 may be used to store software programs and various data, including, but not limited to, applications and operating systems. The processor 710 may integrate an application processor and a modem processor, wherein the application processor primarily processes the operating system, user interface, and applications, and the modem processor primarily processes wireless communications. It is understandable that the above-mentioned modem processor may not be integrated into the processor 710.

[0111] An embodiment of the present invention also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the various processes of the above-mentioned mobile robot positioning method embodiment of multi-source information fusion are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0112] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer-readable storage medium, such as a computer read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk.

[0113] An embodiment of the present invention further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned mobile robot positioning method embodiment of multi-source information fusion, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0114] It should be understood that the chip mentioned in the embodiment of the present invention can also be called a system-on-chip, a system-on-chip, a chip system, or a system-on-chip chip, etc.

[0115] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0116] Furthermore, it should be noted that the scope of the methods and systems of the present invention is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in reverse order, depending on the functions involved. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Furthermore, features described with reference to certain examples may be combined in other examples.

[0117] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for evaluating the degree of ablation of a high-voltage cable buffer layer, characterized in that: The steps include: Step S1, obtaining high-voltage cable parameters, gas detection equipment parameters, and temperature detection equipment parameters. The high-voltage cable parameters include cable model, cable segment length, emissivity, and characteristic gas composition before and after ablation. The gas detection equipment parameters include the wavenumber range and resolution of the gas chromatograph. The temperature detection equipment parameters include the operating distance and ambient temperature of the infrared thermal imager. Step S2: setting air holes at preset intervals along the section of the high-voltage cable to be tested. The air holes are located at the crests of the cable aluminum sheath and have a drilling diameter of 4 mm. Gas is extracted by an air pump and stored in a gas collection bag. Step S3, using a gas chromatograph to detect the gas composition in the gas collection bag, and screening out the cable section containing the characteristic gas based on the ablation characteristic gas composition; Step S4, performing infrared thermal imaging scanning on the screened cable sections, locating abnormal temperature points on the cable outer sheath surface, and collecting gas samples at the abnormal temperature points for a second time; Step S5, calculating the volume fraction of each component in the gas sample at the temperature anomaly point and summarizing the data; Step S6: using the best-worst method to determine the weight of each characteristic gas, and combining the multi-criteria compromise solution ranking method to quantitatively score the temperature anomaly points; Step S7: classify the risk levels according to the scoring results and evaluate the degree of cable buffer layer ablation.

2. The method according to claim 1, characterized in that In step S1, the gas chromatograph model is ZF-301B, and the infrared thermal imager model is UTi80.

3. The method according to claim 1, characterized in that In step S2, the preset distance is 1 km.

4. The method according to claim 1, wherein In step S3, the ablation characteristic gas components include CH4, C2H6, C2H4, C2H2, CO and CO2, and the volume fraction of CO in the gas after the ablation failure is significantly higher than that in the normal operating state.

5. The method according to claim 1, wherein In step S4, the secondary gas sampling and component analysis at the temperature anomaly point adopts the same gas sampling hole parameters as step S2.

6. The method according to claim 1, characterized in that In step S6, the specific steps of the best-worst method include: (a) Determine the characteristic gas index set and select the optimal index with the greatest impact on the assessment target and the worst index with the least impact; (b) Constructing the comparison vector of the best and worst indicators based on the 1-9 scaling method; (c) The optimal weights of characteristic gases are calculated through the optimization model and normalized.

7. The method according to claim 1, characterized in that In step S6, the specific steps of the multi-criteria compromise solution ranking method include: (a) Construct a standardized evaluation matrix and perform trending and dimensionless processing; (b) generating a weighted normalization matrix by combining the weights determined by the best-worst method; (c) Determine the ideal solution and the negative ideal solution; (d) Calculate the group utility value and individual regret value, and determine the comprehensive score of each outlier through the compromise decision evaluation value.

8. The method according to claim 1, characterized in that In step S7, the risk level is divided into five levels: high risk, relatively high risk, medium risk, relatively low risk and low risk according to the group utility value interval.

9. A device for evaluating the degree of ablation of a high-voltage cable buffer layer, which implements the method for evaluating the degree of ablation of a high-voltage cable buffer layer according to any one of claims 1 to 8, characterized in that: include: A parameter acquisition module, configured to acquire high-voltage cable parameters, gas detection equipment parameters, and temperature detection equipment parameters. The high-voltage cable parameters include cable model, cable segment length, emissivity, and characteristic gas composition before and after ablation. The gas detection equipment parameters include the wavenumber range and resolution of the gas chromatograph. The temperature detection equipment parameters include the operating distance and ambient temperature of the infrared thermal imager. The gas collection module is used to set gas holes at preset intervals along the high-voltage cable section to be tested. The gas holes are located at the crest of the cable aluminum sheath and the drilling diameter is 4mm. The gas is extracted by an air pump and stored in a gas collection bag; The gas component screening module is used to detect the gas composition in the gas collection bag using a gas chromatograph, and screen out the cable section containing the characteristic gas based on the ablation characteristic gas composition; The gas sample collection module is used to perform infrared thermal imaging scanning on the screened cable sections, locate the abnormal temperature points on the cable outer sheath surface, and collect gas samples at the abnormal temperature points for the second time; Volume fraction calculation module, used to calculate the volume fraction of each component in the gas sample at the temperature anomaly point and summarize the data; The quantitative scoring module is used to determine the weight of each characteristic gas using the best-worst method and to quantitatively score the temperature anomaly points by combining the multi-criteria compromise solution sorting method; The evaluation module is used to classify risk levels according to the scoring results and evaluate the degree of cable buffer layer ablation.

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