Method and device for evaluating overheating defect of high-voltage bushing, terminal equipment and medium

Abstract

The invention discloses an overheating defect assessment method and device for a current-carrying connection structure in a high-voltage bushing, terminal equipment and a medium, and the method comprises the steps: collecting the surface temperature distribution data of the high-voltage bushing through an infrared temperature measurement device, and obtaining the operation current through the on-site working condition or current monitoring; extracting the temperature of a characteristic temperature point according to the temperature distribution data; calculating temperature characteristic parameters of the surface of the high-voltage bushing according to the characteristic temperature; inputting the operation current and the temperature characteristic parameter into a pre-constructed correlation model to obtain a defect coefficient representing the electrical contact defect degree of the current-carrying connection structure in the high-voltage bushing; and judging whether the defect coefficient exceeds a critical value or not according to a fault evaluation criterion, if so, judging that an overheat fault exists in the high-voltage bushing, and evaluating the level of the overheat fault according to the defect coefficient. According to the method, the degree of the overheating defect of the current-carrying connection structure in the high-voltage bushing can be accurately and efficiently evaluated.

Description

Technical Field

[0001] This invention belongs to the field of high voltage and insulation technology, specifically relating to a method, device, terminal equipment, and medium for assessing overheating defects in the internal current-carrying connection structure of high voltage bushings. Background Technology

[0002] High-voltage bushings, as core insulation and current-carrying components of power equipment, are located at the hub of my country's power transmission and transformation system. Assessing their internal overheating defects is a crucial aspect of power equipment safety monitoring. High-voltage bushings endure high currents, high voltages, and complex harmonics for extended periods during operation, leading to frequent faults. Overheating faults caused by defects in the internal current-carrying connection structure of the bushing are particularly significant. These overheating faults caused by internal defects often develop insidiously in their early stages, but their impact is severe when they occur.

[0003] While traditional infrared thermometry has been widely used for monitoring the surface temperature of bushings, the thermal resistance of the internal insulation material means heat must be conducted through multiple layers of media to the surface. This results in a weakened and delayed surface temperature rise signal extracted by the infrared thermometer, reducing the reliability of relying solely on the absolute value of the surface temperature and making it difficult to distinguish between normal temperature rise and potential overheating. Furthermore, while infrared imaging can detect overheating to some extent, it cannot accurately assess the extent of the overheating defect. Therefore, a more effective method is needed to assess overheating faults caused by defects in the current-carrying connection structure of high-voltage bushings. Summary of the Invention

[0004] To address the problems of traditional infrared thermometry, such as weakened and delayed surface temperature rise signals due to the thermal resistance effect of the internal insulation material of high-voltage bushings, low reliability of relying solely on absolute surface temperature values, and inability to accurately assess the degree of overheating defects, this invention provides a method for assessing overheating defects in the internal current-carrying connection structure of high-voltage bushings. This method extracts surface temperature characteristic parameters and establishes a correlation model based on the operating current to achieve accurate assessment of the degree of overheating defects. This invention also provides corresponding devices, terminal equipment, and storage media.

[0005] The first aspect of this invention provides a method for assessing overheating defects in the internal current-carrying connection structure of a high-voltage bushing, applied to high-voltage bushing condition monitoring scenarios, specifically including:

[0006] The surface temperature distribution data of the high-voltage bushing is collected by an infrared thermometer, and the operating current I is obtained by on-site working conditions or current monitoring.

[0007] Based on the temperature distribution data, extract the temperatures T of feature temperature points A and B. A With T B This parameter eliminates the interference of ambient temperature through temperature difference, highlighting the local temperature rise differences caused by defects.

[0008] According to the characteristic temperature T A With T B Calculate the temperature characteristic parameter ΔT on the surface of the high-pressure bushing;

[0009] The operating current I and the temperature characteristic parameter ΔT are input into a pre-constructed Ik-ΔT correlation model to obtain a defect coefficient k that characterizes the degree of electrical contact defects in the current-carrying connection structure inside the high-voltage bushing. A larger k value indicates a higher degree of electrical contact defects.

[0010] The fault assessment criteria determine whether the defect coefficient k exceeds a critical value. If it does, an overheating fault is determined to exist inside the high-pressure bushing, and the overheating fault level is assessed based on the defect coefficient k. Specifically, the fault is classified into mild, moderate, and severe levels according to the range of k values, and the assessment results are output.

[0011] Furthermore, the infrared temperature measuring device is a non-contact sensor, installed on the temperature-sensitive area of ​​the high-voltage bushing surface, and the distance between it and the high-voltage bushing surface meets the requirements for thermal radiation acquisition accuracy.

[0012] Furthermore, the characteristic temperature point A is located on the outer surface of the insulating sheath at the copper-aluminum transition zone at the upper end of the high-voltage bushing, and the characteristic temperature point B is located on the outer surface of the cap at the upper end of the high-voltage bushing.

[0013] Furthermore, the expression for the temperature characteristic parameter ΔT is:

[0014] ΔT=T A -T B ,

[0015] Among them, T A This represents the temperature of the outer surface of the insulating sheath at the copper-aluminum transition zone at the upper end of the high-voltage bushing, as monitored by the infrared thermometer, in T. B This indicates the temperature of the outer surface of the cap at the upper end of the high-pressure bushing as monitored by the infrared temperature measuring device.

[0016] Furthermore, the expression for the defect coefficient k is:

[0017] k = R2 / R1,

[0018] Where R1 represents the contact resistance of the defect-free bushing current-carrying connection structure, and R2 represents the contact resistance of the deteriorated bushing current-carrying connection structure, with R2 > R1.

[0019] Furthermore, the fault assessment criteria conform to the IEC 60137 standard.

[0020] Furthermore, the Ik-ΔT correlation model is established by simulating and calculating the (I,k,ΔT) data matrix, and is used to characterize the correlation between the operating current I, the defect coefficient k, and the temperature characteristic parameter ΔT.

[0021] A second aspect of the present invention provides a device for assessing overheating defects in the internal current-carrying connection structure of a high-pressure bushing, comprising:

[0022] The data acquisition unit is used to collect the surface temperature distribution data of the high-voltage bushing through an infrared thermometer and obtain the operating current I through on-site operating conditions or current monitoring to ensure the accuracy and real-time performance of data acquisition.

[0023] The feature extraction unit is used to extract the temperature T of feature temperature point A and feature temperature point B based on the temperature distribution data. A With T B This eliminates environmental interference and measurement errors.

[0024] The parameter calculation unit is used to calculate the parameter based on the characteristic temperature T. A With T B Calculate the temperature characteristic parameter ΔT on the surface of the high-pressure bushing;

[0025] The defect assessment unit is used to input the operating current I and the temperature characteristic parameter ΔT into a pre-constructed Ik-ΔT correlation model to obtain the defect coefficient k, which characterizes the degree of electrical contact defects in the current-carrying connection structure inside the high-voltage bushing, and quantifies the degree of electrical contact defects.

[0026] The fault determination unit is used to determine whether the defect coefficient k exceeds a critical value based on the fault assessment criteria. If it exceeds the critical value, it determines that there is an overheating fault inside the high-pressure bushing, and assesses the overheating fault level based on the defect coefficient k. Specifically, it is used to determine whether k exceeds the critical value by referring to the IEC60137 standard and the overheating fault critical curve. If it exceeds the critical value, it classifies the fault level based on the k value.

[0027] The results output unit is used to generate and output an evaluation report containing fault determination results and levels.

[0028] A third aspect of the present invention provides a terminal device for assessing overheating defects in the internal current-carrying connection structure of a high-voltage bushing, comprising:

[0029] A processor is used to execute computer programs and coordinate the work of various hardware components.

[0030] The memory stores computer programs and pre-established Ik-ΔT correlation models, evaluation criteria, and other data.

[0031] The infrared temperature measurement device uses a non-contact sensor, which is installed on the temperature-sensitive area of ​​the sleeve surface to collect temperature distribution data.

[0032] The current monitoring interface is used to connect to the field current monitoring system to obtain the operating current I; wherein, when the processor executes the computer program, it implements the above-mentioned method for assessing the overheating defects of the internal current-carrying connection structure of the high-voltage bushing, and achieves automated assessment through the collaboration of hardware and software.

[0033] A fourth aspect of this invention provides a computer-readable storage medium storing a computer program. When executed by a processor, the program sequentially performs steps such as data acquisition, feature extraction, parameter calculation, defect assessment, fault determination, and result output, thus fully realizing the aforementioned assessment process for overheating defects in the internal current-carrying connection structure of a high-pressure bushing.

[0034] Compared with the prior art, the technical advantages of the present invention are as follows:

[0035] 1. By extracting the temperature difference characteristic parameter ΔT between the copper-aluminum transition zone and the outer surface of the cap, the influence of ambient temperature is eliminated, and the accuracy of defect identification is improved;

[0036] 2. Introduce a defect coefficient k = R2 / R1 to quantify the degree of electrical contact defects, and establish an Ik-ΔT correlation model in conjunction with the operating current I to achieve a quantitative assessment of the degree of defects;

[0037] 3. Establish overheating fault critical curves with reference to the international standard IEC60137 to standardize the assessment criteria and improve the reliability of the assessment results;

[0038] 4. Establish a fully automated evaluation system that integrates data acquisition, feature extraction, model evaluation, and fault determination, enabling contactless and highly efficient assessment of internal overheating defects and providing technical support for high-pressure bushing condition monitoring and fault early warning.

[0039] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

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

[0041] Figure 1 The diagram shown is a flowchart illustrating an assessment method for overheating defects in the internal current-carrying connection structure of a high-pressure bushing, provided by an embodiment of the present invention.

[0042] Figure 2The diagram shown is a schematic diagram of the high-pressure bushing characteristic temperature extraction point provided in an embodiment of the present invention;

[0043] Figure 3 The figure shown is a schematic diagram of the two-dimensional colored contour of the Ik-ΔT association model provided in an embodiment of the present invention;

[0044] Figure 4 The figure shown is a schematic diagram of the critical curve for overheating fault of the watch band finger in the copper-aluminum transition zone provided in an embodiment of the present invention.

[0045] Figure 5 The diagram shown is a structural schematic of an overheating defect assessment device for a high-pressure bushing internal current-carrying connection structure provided in an embodiment of the present invention.

[0046] Figure 6 The diagram shown is a schematic of a terminal device for assessing overheating defects in the internal current-carrying connection structure of a high-voltage bushing, according to an embodiment of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0048] In the specification, claims, and accompanying drawings of this application, the use of terms such as "first" and "second" is for descriptive purposes only, to distinguish different objects, and not to describe a specific order, nor should it be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0049] The terms “comprising” and “having”, and any variations thereof, used in this document are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps, units, or modules is not limited to the steps, units, or modules listed, but may optionally include steps, units, or modules not listed, or may optionally include other steps, units, or modules inherent to such process, method, product, or device.

[0050] The use of "and / or" or "and / or" in the text implies three parallel options. For example, "A and / or B" could mean option A, option B, or a combination of both A and B.

[0051] The term "embodiment" in this document means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0052] like Figure 1 As shown in the figure, this invention provides a method for assessing overheating defects in the internal current-carrying connection structure of a high-pressure bushing, comprising the following steps:

[0053] S100: Collects high-voltage bushing surface temperature distribution data through an infrared temperature measuring device, and obtains the operating current I through on-site working conditions or current monitoring.

[0054] Specifically, the infrared temperature measurement device uses a non-contact sensor, such as the FLIR T1040 infrared thermal imager, with a temperature resolution of 0.02℃, meeting the accuracy requirements for monitoring the surface temperature of high-voltage bushings. The device is installed in front of the temperature-sensitive area of ​​the high-voltage bushing surface, specifically the outer surface of the insulating sheath and the outer surface of the bushing cap near the copper-aluminum transition zone, maintaining a distance of 2-3 meters from the bushing surface to ensure accurate thermal radiation acquisition. Simultaneously, the emissivity setting of the infrared temperature measurement device is adjusted to match the emissivity of the high-voltage bushing surface material (such as ceramic or composite insulation material). Typically, the emissivity is set to 0.92-0.95 for ceramic materials and 0.90-0.93 for composite insulation materials to reduce measurement errors.

[0055] The operating current I is acquired in two ways: For substations equipped with a current monitoring system, the operating current data is obtained in real time by connecting to the system through a dedicated current monitoring interface; for on-site condition monitoring, a high-precision current transformer (e.g., 0.2S class) is used in conjunction with a data acquisition unit to measure and record the operating current of the high-voltage bushing in real time. The sampling frequency of the current measurement is set to 1 time / minute to ensure that fluctuations in the current can be captured.

[0056] S200, Extract the temperature T between characteristic temperature point A and characteristic temperature point B based on the temperature distribution data. A With T B .

[0057] In embodiments of the present invention, such as Figure 2As shown, characteristic temperature point A is precisely located on the outer surface of the insulating sheath at the copper-aluminum transition zone at the upper end of the high-voltage bushing. This area is a typical defect-prone location in the current-carrying connection structure. Due to the electrochemical differences between copper and aluminum materials, defects such as poor contact and oxidation corrosion are prone to occur under long-term high-current operation, leading to localized overheating. Characteristic temperature point B is located on the outer surface of the cap at the upper end of the high-voltage bushing. As a metal component at the top of the bushing, the temperature of the cap is less affected by the internal current-carrying conductor and can be used as a reference temperature point.

[0058] The identification of temperature distribution data employs image processing algorithms. First, the infrared thermal image is denoised using a median filter algorithm to eliminate random noise, with the window size set to 3×3 pixels. Then, temperature regions on the bushing surface are extracted using a threshold segmentation method. Based on the geometry and installation location of the high-voltage bushing, a region of interest (ROI) is defined, excluding thermal interference from surrounding equipment. Within the ROI, temperature gradient analysis automatically identifies abnormal temperature regions. The highest temperature point on the outer surface of the copper-aluminum transition zone insulation sheath is designated as feature temperature point A, and the average temperature point on the outer surface of the bushing cap is designated as feature temperature point B.

[0059] To improve the accuracy of temperature extraction, it is necessary to eliminate the interference of ambient temperature and the influence of measurement errors. The specific method is as follows: Ambient temperature data is collected, and a temperature and humidity sensor is used to monitor the surrounding environment in real time. The ambient temperature compensation function of an infrared thermometer is used to correct the collected temperature data. Simultaneously, a method of averaging multiple measurements is employed; each feature point is measured five times consecutively, and the average value is taken as the final T value. A and T B To reduce random errors.

[0060] S300, according to the characteristic temperature T A With T B Calculate the temperature characteristic parameter ΔT on the surface of the high-pressure bushing.

[0061] The expression for the characteristic parameter of the high-pressure bushing surface temperature is: ΔT = T A -T B T A This indicates the temperature of the outer surface of the insulation sheath at the copper-aluminum transition zone at the upper end of the high-voltage bushing, as monitored by the infrared thermometer, in T. B This represents the temperature of the outer surface of the cap at the top of the high-voltage bushing, as monitored by the infrared thermometer. By calculating the temperature difference between the two points, the influence of ambient temperature changes on the measurement results can be effectively eliminated, highlighting the local temperature rise differences caused by defects in the internal current-carrying connection structure.

[0062] In actual calculations, it is important to ensure consistency in temperature units, using degrees Celsius (°C) as the unit. Furthermore, to improve the reliability of the parameters, a moving average is applied to ΔT with a window size of 10 minutes. This means averaging the ΔT values ​​over the most recent 10 minutes to obtain a smoothed temperature characteristic parameter, thus avoiding the impact of short-term fluctuations on the results.

[0063] S400. Input the operating current I and the temperature characteristic parameter ΔT into the pre-constructed Ik-ΔT correlation model to obtain the defect coefficient k, which characterizes the degree of electrical contact defects in the internal current-carrying connection structure of the high-voltage bushing.

[0064] In embodiments of the present invention, such as Figure 3 The diagram shows a two-dimensional colored contour of the Ik-ΔT correlation model. The Ik-ΔT correlation model is established by obtaining the (I,k,ΔT) data matrix through simulation calculation. First, a thermal-electric coupling simulation model of the internal current-carrying connection structure of the high-pressure bushing is established using finite element analysis software (such as ANSYS). The model includes components such as the current-carrying conductive pipe, copper-aluminum transition joint, insulating sheath, and cap, considering the material parameters (such as electrical conductivity, thermal conductivity, specific heat capacity, etc.) and boundary conditions (such as ambient temperature, convective heat transfer coefficient, etc.) of each component.

[0065] During the simulation, different defect coefficient values ​​k were set. The expression for k is k = R2 / R1, where R1 represents the contact resistance of the defect-free bushing current-carrying connection structure, typically taken as 100 μΩ, and R2 represents the contact resistance of the deteriorated bushing current-carrying connection structure. Depending on the degree of defect, R2 ranges from 100 μΩ to 500 μΩ, corresponding to k values ​​ranging from 1 to 5. For each k value, different operating currents I were applied, ranging from 2000 A to 4000 A, with a step size of 200 A. The surface temperature distribution of the high-voltage bushing under different combinations of I and k was calculated, and the temperatures of characteristic temperature points A and B were extracted. The temperature characteristic parameter ΔT was then calculated.

[0066] Through the above simulation calculations, a large number of (I,k,ΔT) data points were obtained, forming a data matrix. Then, a multivariate regression analysis method was used to establish a correlation model between the operating current I, the defect coefficient k, and the temperature characteristic parameter ΔT. After model validation, the optimal correlation model expression was determined to be: ΔT=a·I 2 ·k+b·I+c, where a, b, and c are model parameters obtained by least squares fitting, with specific values ​​of a=5.2×10^-8, b=2.1×10^-3, and c=1.5.

[0067] In practical applications, the measured operating current I and the calculated temperature characteristic parameter ΔT are substituted into the I-k-ΔT correlation model, and the defect coefficient k is solved by numerical iteration. For example, given that the operating current I of a certain high-voltage bushing is 3000 A and the temperature characteristic parameter ΔT is 15 °C, substituting into the model gives:

[0068] 15 = 5.2×10^-8×(3000)^2·k + 2.1×10^-3×3000 + 1.5. Solving for k gives k = (15 - 2.1×10^-3×3000 - 1.5) / (5.2×10^-8×9×10^6) = (15 - 6.3 - 1.5) / (0.468) = 7.2 / 0.468 ≈ 15.38.

[0069] S500. Determine whether the defect coefficient k exceeds the critical value according to the fault assessment criterion. If it does, it is determined that there is an overheating fault inside the high-voltage bushing, and the overheating fault level is evaluated based on the defect coefficient k.

[0070] In the embodiment of the present invention, the formation of the fault assessment criterion refers to the IEC60137 standard, which clearly stipulates the internal temperature safety limit of dry resin-impregnated paper-insulated bushings, that is, the temperature of the internal current-carrying conductive tube shall not exceed 90 °C. Through thermal-electrical coupling simulation, the relationship between the hottest spot temperature inside the high-voltage bushing and the defect coefficient k under different operating currents I is analyzed, and the critical value of the defect coefficient k when the hottest spot temperature inside reaches 90 °C is extracted to form the critical curve of the overheating fault of the current-carrying connection structure in the copper-aluminum transition zone of the high-voltage bushing, as Figure 4 shown.

[0071] Specifically, in the simulation model, the temperature of the internal current-carrying conductive tube is set to 90 °C, and the critical value of the corresponding defect coefficient k under different operating currents I is calculated. For example, when I = 2000 A, the critical k value is 5.0; when I = 2500 A, the critical k value is 3.5; when I = 3000 A, the critical k value is 2.5; when I = 3500 A, the critical k value is 1.8; when I = 4000 A, the critical k value is 1.2. Plotting these critical values as a curve gives the critical curve of the overheating fault.

[0072] The overheating fault level is divided according to the numerical range of the defect coefficient k, and the specific criteria are as follows:

[0073] Minor defect: k ≤ 1.5 times the critical value. At this time, the temperature of the internal current-carrying conductive tube is between 90 °C and 95 °C, and the fault develops slowly, and regular monitoring can be carried out;

[0074] Moderate defect: 1.5 times the critical value < k ≤ 2.5 times the critical value. The internal temperature is between 95 °C and 105 °C, and maintenance needs to be arranged;

[0075] Severe defect: k > 2.5 times the critical value, internal temperature exceeds 105℃, posing a serious safety hazard, requiring immediate power outage.

[0076] Taking an operating current of I = 3000A as an example, the critical k value is 2.5:

[0077] If the calculated k = 3.0 (below 2.5 × 1.5 = 3.75), it is judged as a minor defect;

[0078] If k = 4.0 (between 3.75 and 2.5 × 2.5 = 6.25), it is judged as a moderate defect;

[0079] If k = 7.0 (greater than 6.25), it is judged as a severe defect.

[0080] Complete the high-voltage bushing overheating fault assessment and output the assessment results. The output of the assessment results includes a visual interface display and report generation. The visual interface displays the real-time change curves of the operating current I, temperature characteristic parameter ΔT, and defect coefficient k in chart form, and uses different colors to indicate the fault level: green indicates normal, yellow indicates minor defect, orange indicates moderate defect, and red indicates severe defect. At the same time, the interface displays the current assessment conclusions and recommended measures.

[0081] The report generation function automatically generates a detailed assessment report, including:

[0082] Basic equipment information: high-voltage bushing model, installation location, operating number, etc.;

[0083] Data acquisition information: parameter settings and acquisition time range of infrared temperature measurement device and current monitoring;

[0084] Characteristic parameter calculation process: T A T B The specific value, and the calculation result of ΔT;

[0085] Defect assessment results: The calculation process and results of the k value, and a comparative analysis with the critical value;

[0086] Fault level determination: Clearly define the determination result and the corresponding fault level;

[0087] Recommended measures: Based on the fault level, propose corresponding handling suggestions, such as regular monitoring, arranging maintenance, or immediate power outage.

[0088] The following is a specific application example to illustrate the implementation process of the present invention in detail:

[0089] The high-voltage bushing of the No. 1 main transformer in a 220kV substation, model BRLW-220 / 1250-6, operation number 2201TA, was assessed for overheating defects using the evaluation method of this invention during routine inspection.

[0090] Step 1: Install the FLIR T1040 infrared thermal imager 2.5 meters directly in front of the bushing, set the emissivity to 0.94 (ceramic surface), ambient temperature to 25℃, and humidity to 60%. Simultaneously, obtain the operating current I through the substation current monitoring system; the current current is 3200A.

[0091] Step 2: Process the acquired infrared thermal image to identify the highest temperature point A on the outer surface of the insulation sheath in the copper-aluminum transition zone, with temperature T. A =58℃; the average temperature point B on the outer surface of the general's cap, temperature T B =40℃.

[0092] Step 3: Calculate the temperature characteristic parameter ΔT = T A -T B =58-40=18℃.

[0093] Step 4: Substitute I = 3200A and ΔT = 18℃ into the Ik-correlation model

[0094] ΔT = 5.2 × 10^-8 · I 2 ·k+2.1×10^-3·I+1.5, we get:

[0095] 18=5.2×10^-8×(3200)^2·k+2.1×10^-3×3200+1.5

[0096] The calculation yields:

[0097] 5.2×10^-8×10240000·k=18-6.72-1.5=9.78

[0098] 0.53248·k=9.78

[0099] k = 9.78 / 0.53248 ≈ 18.37

[0100] Step 5: Referring to the IEC60137 standard, when I = 3200A, the critical k value is found to be 2.2 through the overheating fault critical curve. Since 18.37 > 2.2 × 2.5 = 5.5, it is judged as a severe defect, and the temperature of the internal current-carrying conductive tube exceeds 105℃, indicating a serious overheating fault.

[0101] Step 6: Output the evaluation results. The visualization interface displays a red warning, and the evaluation report recommends immediate power outage and maintenance. Subsequently, a power outage inspection was conducted on the bushing, and it was found that the contact fingers at the copper-aluminum transition joint were severely oxidized, with a contact resistance of 450μΩ (R1=100μΩ), k=450 / 100=4.5, which is consistent with the calculated result, verifying the accuracy of the method of the present invention.

[0102] like Figure 5 As shown, this embodiment of the invention also provides a device for assessing overheating defects in the internal current-carrying connection structure of a high-pressure bushing, comprising:

[0103] The data acquisition unit 100 is used to acquire surface temperature distribution data of the high-voltage bushing through an infrared thermometer and obtain the operating current I through on-site operating conditions or current monitoring. This unit includes a data interface module for communicating with the infrared thermometer and current monitoring system to achieve real-time acquisition and transmission of temperature and current data; it also includes a data preprocessing module to filter, denoise, and convert the acquired data to ensure accuracy and consistency.

[0104] Feature extraction unit 200 is used to extract the temperature T of feature temperature point A and feature temperature point B based on the temperature distribution data. A With T B This unit includes an image processing module that uses the aforementioned noise reduction, threshold segmentation, and temperature gradient analysis algorithms to automatically identify feature temperature points; it also includes a temperature correction module that compensates and corrects the extracted temperature based on ambient temperature and humidity data.

[0105] Parameter calculation unit 300, used to calculate the characteristic temperature T A With T B Calculate the temperature characteristic parameter ΔT on the surface of the high-pressure bushing. This unit includes a temperature difference calculation module, which executes ΔT = T. A -T B The calculation includes a moving average module to smooth the time series of ΔT, improving the stability of the parameters.

[0106] The defect assessment unit 400 is used to input the operating current I and the temperature characteristic parameter ΔT into a pre-constructed Ik-ΔT correlation model to obtain a defect coefficient k that characterizes the degree of electrical contact defects in the current-carrying connection structure inside the high-voltage bushing, thus quantifying the degree of electrical contact defects. This unit includes a model storage module that pre-stores the parameters and algorithms of the Ik-ΔT correlation model; it also includes a numerical calculation module that performs model substitution and solution to obtain the value of k.

[0107] The fault determination unit 500 is used to determine whether the defect coefficient k exceeds a critical value based on the fault assessment criteria. If it exceeds the critical value, it is determined that there is an overheating fault inside the high-pressure bushing, and the overheating fault level is assessed based on the defect coefficient k. This unit includes a criterion storage module that stores IEC60137 standard and overheating fault critical curve data; it also includes a level classification module that classifies the fault level based on the comparison between the k value and the critical value.

[0108] The results output unit 600 is used to output the evaluation results. This unit includes an interface display module to generate a visual interface; it also includes a report generation module to automatically generate an evaluation report and supports printing and export functions.

[0109] like Figure 6 As shown, this embodiment of the invention also provides a terminal device for assessing overheating defects in the internal current-carrying connection structure of a high-voltage bushing, comprising:

[0110] The processor is a high-performance Intel Core i7-10700K processor with a clock speed of 3.8GHz, which has powerful data processing and computing capabilities to execute computer programs and coordinate the work of various hardware components.

[0111] The storage system includes 16GB of DDR4 RAM and a 1TB SSD, storing computer programs, Ik-ΔT correlation models, evaluation criteria, historical data, and more. The RAM ensures fast program execution, while the SSD provides ample storage space and rapid data read / write capabilities.

[0112] The infrared temperature measurement device, model FLIR T1040, as mentioned above, is used to collect temperature distribution data on the surface of the high-voltage bushing. It is connected to the processor via a USB 3.0 interface to achieve high-speed data transmission.

[0113] The current monitoring interface uses an RS485 communication interface to connect with the substation's current monitoring system, obtain the operating current I, and supports the Modbus RTU communication protocol to ensure the stability and reliability of data transmission.

[0114] In addition, the terminal equipment also includes a monitor (23.8-inch IPS display with a resolution of 1920×1080), keyboard, mouse and other input / output devices, as well as a power module (220V AC input, 500W power) to provide a stable power supply for the entire device.

[0115] When the processor executes the computer program, it sequentially calls the functions of the data acquisition unit, feature extraction unit, parameter calculation unit, defect assessment unit, fault judgment unit, and result output unit to realize the above-mentioned method for assessing overheating defects in the internal current-carrying connection structure of the high-pressure bushing.

[0116] This invention also provides a computer-readable storage medium having a computer program stored thereon. When executed by a processor, the computer program performs the following steps:

[0117] (1) Control the infrared temperature measurement device to collect the temperature distribution data on the surface of the high-voltage bushing, and obtain the operating current I through the current monitoring interface;

[0118] (2) Process the temperature distribution data and extract the temperature T at characteristic temperature points A and B. A With T B ;

[0119] (3) Calculate the temperature characteristic parameter ΔT = T A -T B ;

[0120] (4) Call the pre-established Ik-ΔT correlation model, input I and ΔT, and calculate the defect coefficient k;

[0121] (5) Determine whether k exceeds the critical value based on the fault assessment criteria. If it does, assess the fault level.

[0122] (6) Generate and output the evaluation results.

[0123] The computer program can be written in programming languages ​​such as C++ and Python, and adopts a modular design, including a data acquisition module, an image processing module, a parameter calculation module, a model evaluation module, a fault determination module, and a result output module. The modules interact with each other and call functions through interface functions.

[0124] The computer-readable storage medium can be any medium capable of storing program code, such as a USB flash drive, portable hard drive, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0125] In practical applications, the evaluation method of this invention can be integrated with the online monitoring system of substations to achieve real-time monitoring and early warning of high-voltage bushing overheating defects. The system sampling frequency is set to once per minute, generating an evaluation report daily, which is stored on a server for maintenance personnel to review. When a severe defect is detected, the system automatically sends SMS and email alarms to notify relevant personnel to handle the situation.

[0126] In summary, this invention extracts the temperature difference characteristic parameters between the copper-aluminum transition zone and the outer surface of the bushing, establishes a correlation model in conjunction with the operating current, introduces a defect coefficient k to quantify the degree of defect, and forms an evaluation criterion by referring to industry standards, thereby achieving a non-contact, high-efficiency, and accurate assessment of overheating defects inside high-pressure bushings.

[0127] This method has the following advantages:

[0128] 1. High accuracy: By eliminating the influence of ambient temperature through temperature difference and combining the Ik-ΔT correlation model established by thermo-electric coupling simulation, it can accurately reflect the degree of defects in the internal current-carrying connection structure;

[0129] 2. High reliability: Methods such as averaging multiple measurements and data smoothing are used to reduce the impact of measurement errors and random factors;

[0130] 3. High degree of standardization: Evaluation criteria are established with reference to the IEC 60137 standard, making the evaluation results comparable and authoritative;

[0131] 4. High degree of automation: It achieves full automation from data collection to result output, reducing manual intervention and improving evaluation efficiency;

[0132] 5. Highly practical: Provides detailed assessment reports and troubleshooting suggestions, offering strong support for the operation and maintenance decisions of high-voltage bushings.

[0133] Those skilled in the art will realize that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for evaluating a defect of overheating of a current-carrying connection structure inside a high-voltage bushing, characterized by, The method comprises: acquiring high-voltage bushing surface temperature distribution data by an infrared temperature measuring device, and obtaining operating current I through on-site working condition or current monitoring; According to the temperature distribution data, a feature temperature point A and a feature temperature point B are extracted A and T B ; According to the characteristic temperature T A With T B Calculating the temperature characteristic parameter ΔT of the high-voltage bushing surface; inputting the operating current I and the temperature characteristic parameter ΔT into a pre-constructed I-k-ΔT correlation model to obtain a defect coefficient k representing the electrical contact defect degree of the internal current-carrying connecting structure of the high-voltage bushing; determining whether the defect coefficient k exceeds a critical value according to a fault evaluation criterion, and if so, determining that there is an overheating fault in the internal high-voltage bushing, and evaluating the overheating fault level according to the defect coefficient k.

2. The method of claim 1, wherein, The infrared temperature measuring device is a non-contact sensor installed on a temperature sensitive area of the high-voltage bushing surface, and the distance between the infrared temperature measuring device and the high-voltage bushing surface meets the thermal radiation collection accuracy requirement.

3. The method of claim 1, wherein, The characteristic temperature point A is located at the outer surface of the insulation covering jacket at the copper-aluminum transition zone of the upper end of the high-voltage bushing, and the characteristic temperature point B is located at the outer surface of the general hat at the upper end of the high-voltage bushing.

4. The method of claim 1, wherein, The expression of the temperature characteristic parameter ΔT is: ΔT = T A - T B , Wherein, T A represents the temperature of the outer surface of the insulating cover at the copper-aluminum transition zone at the upper end of the high-voltage bushing monitored by the infrared temperature measuring device, T B represents the temperature of the outer surface of the general cap at the upper end of the high-voltage bushing monitored by the infrared temperature measuring device.

5. The method of claim 1, wherein, The expression of the defect coefficient k is: k = R2 / R1, wherein R1 represents the contact resistance of the current-carrying connecting structure of the non-defective bushing, R2 represents the contact resistance of the current-carrying connecting structure of the deteriorated bushing, and R2>R1.

6. The method of claim 1, wherein, The fault evaluation criterion conforms to the IEC60137 standard.

7. The method of claim 1, wherein, The I-k-ΔT correlation model is established by simulating a (I, k, ΔT) data matrix, and is used to represent the correlation between the operating current I, the defect coefficient k and the temperature characteristic parameter ΔT.

8. A device for evaluating a defect of overheating of a high-voltage bushing internal current-carrying connection structure, characterized by, The device comprises: a data acquisition unit configured to acquire high-voltage bushing surface temperature distribution data by an infrared temperature measuring device, and obtain operating current I through on-site working condition or current monitoring; a feature extraction unit configured to extract a feature temperature point A and a feature temperature point B from the temperature distribution data A with T B ; a parameter calculation unit for calculating a temperature characteristic parameter ΔT of the high-voltage bushing surface from the characteristic temperature T A with T B calculating the temperature characteristic parameter ΔT of the high-voltage bushing surface; a defect evaluation unit configured to input the operating current I and the temperature characteristic parameter ΔT into a pre-constructed I-k-ΔT correlation model to obtain a defect coefficient k representing the electrical contact defect degree of the internal current-carrying connecting structure of the high-voltage bushing; a fault determination unit configured to determine whether the defect coefficient k exceeds a critical value according to a fault evaluation criterion, and if so, determine that there is an overheating fault in the internal high-voltage bushing, and evaluate the overheating fault level according to the defect coefficient k.

9. A terminal device for overheat defect assessment of a current-carrying connection structure inside a high-voltage bushing, characterized by comprise: a processor; a memory storing a computer program; an infrared temperature measuring device configured to acquire high-voltage bushing surface temperature distribution data; a current monitoring interface configured to obtain operating current I; wherein the processor implements the high-voltage bushing internal current-carrying connecting structure overheating defect evaluation method according to any one of claims 1-7 when executing the computer program.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the high-voltage bushing internal current-carrying connecting structure overheating defect evaluation method according to any one of claims 1-7.

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