A multi-dimensional interface stress monitoring device and method for vehicle-mounted cable terminals

Abstract

The present invention provides a multi-dimensional interface stress monitoring device and method for vehicle-mounted cable terminals. The method comprises: collecting temperature, strain, and partial discharge current data from the vehicle-mounted cable terminal using a thermocouple and a full-bridge strain gauge at the interface between the rigid support tube and the stress control tube of the vehicle-mounted cable terminal, as well as a high-frequency current transformer sleeved on a shielded lead-out wire; performing an environmental overload determination based on the three sets of temperature, strain, and partial discharge current data, and determining the environmental overload determination result; if the environmental overload determination result is overload, determining insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data based on the three sets of temperature, strain, and partial discharge current data and their corresponding insulation association tables; and determining the degradation level of the vehicle-mounted cable terminal based on the insulation thermal fatigue damage, creep, and electrical performance data, and displaying the corresponding information. The present invention improves the long-term operational reliability of cable accessories.

Description

Technical Field

[0001] The present invention relates to the technical field of fault diagnosis and monitoring, and in particular to a multi-dimensional interface stress monitoring device and method for a vehicle-mounted cable terminal. Background Art

[0002] In the field of fault diagnosis and monitoring technology for high-voltage equipment on EMU trains, onboard cable terminals, as key components connecting the cable body and related electrical equipment, must possess excellent electrical insulation performance and mechanical strength. However, during operation, they are subjected to the combined effects of electrical stress, thermal stress, and mechanical stress for a long time, making them prone to combined insulation failure, which in turn leads to a decrease in insulation level. Relevant research has shown that the deterioration of interface performance can cause air gaps to form at the interface of cable composite insulation. Under the repeated effects of electric fields, extreme temperatures, mechanical factors, and other factors, internal defects will gradually expand and worsen, and may eventually cause the cable terminal to break down or explode, seriously affecting the normal operation of EMU trains.

[0003] Currently, an existing multi-dimensional interface stress monitoring method for vehicle-mounted cable terminals primarily uses a single monitoring method to periodically detect a stress parameter of the cable terminal. For example, only temperature or partial discharge current is monitored, and the monitoring process often requires manual intervention, making real-time, comprehensive monitoring impossible. A major drawback of this method is its single monitoring method, which makes it impossible to simultaneously and comprehensively monitor multi-dimensional interface stress parameters such as temperature, strain, and partial discharge current in real time. This makes it difficult to accurately grasp the actual operating status of the cable terminal, and its ability to prevent partial discharge caused by deterioration of the cable terminal interface stress is limited, failing to meet the demand for improving the long-term operational reliability of cable accessories. Summary of the Invention

[0004] The present invention provides a multi-dimensional interface stress monitoring device and method for a vehicle-mounted cable terminal, aiming to improve the long-term operating reliability of cable accessories.

[0005] In a first aspect, the present invention provides a multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal, comprising:

[0006] Temperature data, strain data, and partial discharge current data of the on-board cable terminal are collected through thermocouples and full-bridge strain gauges at the interface between the rigid support tube and the stress control tube of the on-board cable terminal, as well as a high-frequency current transformer sleeved on the shielded lead-out wire; the thermocouples and full-bridge strain gauges are respectively arranged at 0°, 120°, and 240° positions, as well as at 60°, 180°, and 300° positions in the geometric circular area of ​​the interface;

[0007] Performing an environmental overload judgment based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data, and determining an environmental overload judgment result;

[0008] If the environmental overload determination result is overload, determining insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data and their corresponding insulation association tables;

[0009] Based on the insulation thermal fatigue damage data, the insulation creep data, and the insulation electrical performance data, a degradation level of the vehicle-mounted cable terminal is determined, and corresponding information is displayed.

[0010] In a second aspect, the present invention further provides a multi-dimensional interface stress monitoring device for a vehicle-mounted cable terminal, which is applied to the multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal as described in the first aspect; the multi-dimensional interface stress monitoring device for a vehicle-mounted cable terminal comprises:

[0011] a data acquisition module for collecting temperature data, strain data, and partial discharge current data of the on-board cable terminal through thermocouples and full-bridge strain gauges at the interface between the rigid support tube and the stress control tube of the on-board cable terminal, and a high-frequency current transformer sleeved on the shielded lead-out wire; the thermocouples and full-bridge strain gauges are respectively arranged at positions 0°, 120°, and 240°, and at positions 60°, 180°, and 300°, of the geometric circular area of ​​the interface;

[0012] An environmental overload determination module is configured to determine an environmental overload determination based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data, and to determine an environmental overload determination result;

[0013] a data query module, configured to determine insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data and their corresponding insulation association tables if the environmental overload determination result is overload;

[0014] A monitoring and display module is used to determine the degradation level of the vehicle-mounted cable terminal based on the insulation thermal fatigue damage data, the insulation creep data and the insulation electrical performance data, and display corresponding information.

[0015] In a third aspect, the present invention further provides an electronic device comprising: a memory for storing a computer software program; and a processor for reading and executing the computer software program, thereby implementing any of the above-mentioned multi-dimensional interface stress monitoring methods for a vehicle-mounted cable terminal.

[0016] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium, wherein the storage medium stores a computer software program, and when the computer software program is executed by a processor, it implements a multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal as described in any one of the above-mentioned methods.

[0017] In a fifth aspect, the present invention further provides a computer program product, comprising a computer program, which, when executed by a processor, implements any of the above-mentioned multi-dimensional interface stress monitoring methods for a vehicle-mounted cable terminal.

[0018] The multi-dimensional interface stress monitoring device and method for vehicle-mounted cable terminals provided by the embodiments of the present invention, by setting sensors at multiple key locations of the cable terminal to collect temperature data, strain data, and partial discharge current data in real time, ensures the comprehensiveness and accuracy of the acquired data, avoids the limitations of a single monitoring method, and thus can comprehensively and accurately grasp the operating status of the cable terminal. The collected data is further associated with the insulation association table to achieve a visual assessment of the insulation status of the cable terminal, overcoming the disadvantage of being unable to accurately judge the insulation status. Furthermore, through environmental overload determination, abnormal conditions during the operation of the cable terminal can be promptly discovered, avoiding further deterioration of the abnormal conditions, and improving the ability to prevent cable terminal failures, thereby effectively reducing the probability of terminal insulation failure or explosion events caused by abnormal internal conditions of the vehicle-mounted cable terminal, avoiding the occurrence of parking and power outage accidents, solving the problem of being unable to conduct real-time and comprehensive monitoring, and improving the long-term operational reliability of cable accessories. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a control flow chart of each sensor provided by an embodiment of the present invention;

[0020] Figure 2 This is a software operation flow chart provided by an embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the installation positions of various sensors provided in an embodiment of the present invention;

[0022] Figure 4 1 is a flow chart of a multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal provided by an embodiment of the present invention;

[0023] Figure 5 2 is a schematic structural diagram of a multi-dimensional interface stress monitoring device for a vehicle-mounted cable terminal provided by an embodiment of the present invention;

[0024] Figure 6 An embodiment diagram of an electronic device provided by an embodiment of the present invention;

[0025] Figure 7 An embodiment diagram of a computer-readable storage medium provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings of the present invention.

[0027] Optional, see Figure 1 The embodiment of the present invention provides a control flow chart of a high-frequency current transformer (KCT-40), a full-bridge strain gauge, and a MAX6675 type thermocouple.

[0028] Optional, see Figure 2 , Figure 2 This is a software operation flow chart provided by an embodiment of the present invention. When the single-chip microcomputer is powered on and starts running, monitoring instructions are sent to the thermocouple, full-bridge strain gauge and KCT-40. The thermocouple, full-bridge strain gauge and KCT-40 respectively start to detect the current temperature data, strain data and PD signal (partial discharge current data) of the vehicle cable terminal. The sensors convert the collected data into digital signals and send them to the single-chip microcomputer for processing. The signals are then sent to the mobile phone through the ESP8266WIFI module, or the data is displayed on the online monitoring interface.

[0029] Optional, see Figure 3 , Figure 3 This is a schematic diagram of the installation locations of the various sensors provided in an embodiment of the present invention. Thermocouples are buried as follows: one thermocouple is installed at 0°, 120°, and 240°, respectively, within the geometric circular area at the interface between the rigid support tube and the stress control tube at the cable terminal. The full-bridge strain gauge is buried as follows: one full-bridge strain gauge is installed at 60°, 180°, and 300°, respectively, within the geometric circular area at the interface between the rigid support tube and the stress control tube at the cable terminal. The high-frequency current transformer is attached to the shielded lead wire of the cable terminal via a clip.

[0030] Alternatively, during the on-board cable terminal fabrication process, strip 500mm of the outer sheath from the cable end, saw off the steel tape and inner padding beyond 50mm from the outer sheath break, then weld a ground wire securely to the remaining steel tape and lead sheath using a blowtorch. Strip the lead sheath beyond 120mm from the outer sheath break, retaining 20mm of the turnkey insulation from the lead sheath opening. Insert the lead sheath into the stress tube 20mm from the turnkey insulation and heat-secure it. Then, place three sets of full-bridge strain gauges and three sets of thermocouples at a 60° angle around the base of the stress tube and secure them with glue. Next, crimp the rigid support tube so that the sensors are embedded between the stress tube and the rigid support tube, leaving sufficient lead length. Heat-secure the connection from the center outward. Finally, install the shielding mesh and ground wire, and apply the outer insulation sealing tube. After fabrication is complete, secure the high-frequency current transformer to the shielded cable using snaps.

[0031] Optional, see Figure 4 , Figure 4 : is a flow chart of a multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal provided by the present invention. In an embodiment of the present invention, the execution subject of the multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal is a single-chip microcomputer. Therefore, the multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal includes:

[0032] In step 10, temperature, strain, and partial discharge current data from the vehicle cable terminal are collected using thermocouples and full-bridge strain gauges at the interface between the rigid support tube and the stress control tube, as well as high-frequency current transformers mounted on the shielded lead wires. The thermocouples and full-bridge strain gauges are placed at 0°, 120°, and 240°, and at 60°, 180°, and 300°, respectively, within the geometrically circular region of the interface.

[0033] Optionally, the single-chip microcomputer of the embodiment of the present invention stores a temperature-insulation correlation table, a strain-insulation correlation table and a partial discharge-insulation correlation table, wherein the temperature-insulation correlation table represents the correspondence between the thermal characteristic values ​​and the insulation thermal fatigue damage conditions, the strain-insulation correlation table represents the correspondence between the strain characteristic values ​​and the insulation creep conditions, and the partial discharge-insulation correlation table represents the correspondence between the local discharge flow and the insulation electrical performance conditions. Furthermore, after the single-chip microcomputer is powered on and starts running, the temperature data, strain data and partial discharge current data of the on-board cable terminal are collected through thermocouples, full-bridge strain gauges and high-frequency current transformers.

[0034] Among them, the principles of each sensor are as follows: thermocouples convert temperature changes into thermoelectric potential based on the Seebeck effect; full-bridge strain gauges utilize the resistance strain effect. When the full-bridge strain gauge is subjected to strain, its resistance value changes and is converted into a voltage signal through a Wheatstone bridge; high-frequency current transformers are based on the principle of electromagnetic induction and convert the high-frequency partial discharge current flowing through the shielded lead wire into a voltage signal.

[0035] Step 20 : Performing an environmental overload determination based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data to determine an environmental overload determination result.

[0036] Furthermore, the three sets of temperature data collected by the three thermocouples at 0°, 120° and 240°, and the three sets of strain data collected by the full-bridge strain gauge at 60°, 180° and 300° are combined with the partial discharge current data to perform an environmental overload judgment and determine the environmental overload judgment result, wherein the environmental overload judgment result is to determine whether the environment is overloaded, as specifically shown in the process from step 201 to step 203.

[0037] Step 30: If the environmental overload determination result is overload, insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data are determined based on the three sets of temperature data, three sets of strain data, and partial discharge current data and their corresponding insulation association tables.

[0038] Furthermore, if the environmental overload determination is overload, insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data are further determined. Specifically, the collected temperature data, strain data, and partial discharge current data are mapped to the corresponding insulation correlation tables (temperature-insulation correlation table, strain-insulation correlation table, and partial discharge-insulation correlation table) to obtain the corresponding insulation status parameters. The temperature-insulation correlation table, strain-insulation correlation table, and partial discharge-insulation correlation table are obtained through extensive experimental and statistical analysis of actual operating data, establishing a correspondence between the physical quantity values ​​and the insulation status parameters.

[0039] In this embodiment, the temperature-insulation correlation table in the microcontroller's program memory (Flash) is a two-dimensional table with temperature values ​​(°C) in the horizontal columns and insulation thermal fatigue damage coefficients in the vertical columns. The data in the table is obtained by conducting accelerated thermal aging tests on cable terminal insulation materials at different temperatures. For example, at a temperature of 80°C, the corresponding insulation thermal fatigue damage coefficient is 0.1; at a temperature of 90°C, the damage coefficient is 0.3; at a temperature of 100°C, the damage coefficient is 0.6, and so on. The strain-insulation correlation table is also a two-dimensional table with strain values ​​(με) in the horizontal columns and insulation creep coefficients in the vertical columns. The data is obtained from creep tests of insulation materials under different strains. For example, at a strain of 1000 με, the creep coefficient is 0.2; at a strain of 1500 με, the creep coefficient is 0.5; at a strain of 2000 με, the creep coefficient is 0.8, and so on.

[0040] The partial discharge insulation correlation table is established based on the relationship between the peak value and number of pulses of the partial discharge current and the degree of degradation of the insulation electrical performance, and can be in the form of a three-dimensional table or a mathematical model.

[0041] When the environmental overload judgment result is overload, the microcontroller calculates the average value of the three sets of temperature data collected in step 10. T avg or maximum value T max (Specifically according to the definition of the association table), find the corresponding insulation thermal fatigue damage data in the temperature insulation association table. Assume T avg =85℃, and the insulation thermal fatigue damage data is found to be 0.25 by linear interpolation in the temperature insulation correlation table. For the strain data, the maximum value ε among the three sets of strain data is taken. max=1200με, and looking it up in the strain-insulation correlation table, we get an insulation creep value of 0.35 (using linear interpolation of 1000με to 0.2 and 1500με to 0.5). For the partial discharge current data, assuming a peak value of 12pC and eight pulses per unit time, we calculate the insulation electrical performance data to 0.9 using the mathematical model in the partial discharge-insulation correlation table. For example, the model can be expressed as: insulation electrical performance data = 1 - 0.05 * (peak current / 10pC + number of pulses / 10).

[0042] Step 40 : determining the degradation level of the vehicle-mounted cable terminal based on the insulation thermal fatigue damage data, the insulation creep data, and the insulation electrical performance data, and displaying corresponding information.

[0043] Furthermore, the degradation level of the vehicle cable terminal is determined based on the insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data, as specifically described in steps 401 to 404. Furthermore, the single-chip microcomputer transmits the corresponding information to the vehicle monitoring display terminal via serial communication. The display terminal displays the corresponding information in text and graphics, such as three sets of temperature data, three sets of strain data, and partial discharge current data, as well as the degradation level of the vehicle cable terminal.

[0044] The embodiment of the present invention sets sensors at multiple key locations of the cable terminal to collect temperature data, strain data, and partial discharge current data in real time, thereby ensuring the comprehensiveness and accuracy of the acquired data and avoiding the limitations of a single monitoring method, thereby being able to fully and accurately grasp the operating status of the cable terminal. The collected data is further associated with the insulation association table to achieve a visual assessment of the insulation status of the cable terminal, overcoming the disadvantage of being unable to accurately judge the insulation status. Furthermore, through environmental overload judgment, abnormal conditions during the operation of the cable terminal can be discovered in a timely manner, avoiding further deterioration of the abnormal conditions, and improving the ability to prevent cable terminal failures, thereby effectively reducing the probability of terminal insulation failure or explosion events caused by abnormal internal conditions of the vehicle-mounted cable terminal, avoiding the occurrence of parking and power outages, solving the problem of being unable to conduct real-time and comprehensive monitoring, and improving the long-term operational reliability of cable accessories.

[0045] In one embodiment, steps 201 to 203 are described as follows:

[0046] Step 201 : for any two temperature data combinations in the three sets of temperature data and any two strain data combinations in the three sets of strain data, determine the temperature difference of each temperature data combination and the strain difference of each strain data combination.

[0047] Optionally, the spatial distribution of temperature and strain is analyzed. For any two temperature data combinations from the three sets of temperature data, and any two strain data combinations from the three sets of strain data, the temperature difference for each temperature data combination and the strain difference for each strain data combination are determined. Spatial distribution of temperature or strain may indicate abnormal conditions such as poor contact, localized overheating, or uneven stress within the cable terminal.

[0048] In one embodiment, continuing with the embodiment in step 10, the three sets of temperature data collected by the single chip microcomputer are recorded as T1, T2, and T3, and the three sets of strain data are recorded as ε1, ε2, and ε3. In step 201, the single chip microcomputer needs to calculate the difference between all possible temperature data combinations and the difference between all possible strain data combinations.

[0049] For temperature data, there are C(3,2)=3 combinations, namely (T1, T2), (T1, T3), (T2, T3), and the corresponding temperature differences are: ΔT 12 =|T1-T2|, ΔT 13 =|T1-T3|, ΔT 23 =|T2-T3|.

[0050] For strain data, there are also three combinations, namely (ε1, ε2), (ε1, ε3), (ε2, ε3), and the corresponding strain differences are: Δε 12 =|ε1-ε2|, Δε 13 =|ε1-ε3|, Δε 23 =|ε2-ε3|.

[0051] For example, assuming the three sets of temperature data collected are T1=82℃, T2=78℃, and T3=85℃, the temperature difference is calculated as follows: ΔT 12 =|82-78|=4℃, ΔT 13 =|82-85|=3℃, ΔT 23 =|78-85|=7℃.

[0052] The three sets of strain data are ε1=1200με, ε2=1000με, and ε3=1100με. The strain difference is calculated as follows: Δε 12 =|1200-1000|=200με, Δε 13 =|1200-1100|=100με, Δε 23 =|1000-1100|=100με.

[0053] Step 202: If the temperature difference of at least one temperature data combination is greater than a preset temperature difference threshold, or / and the strain difference of at least one strain data combination is greater than a preset strain difference threshold, or / and the partial discharge current data is greater than a preset partial discharge flow rate, then the environmental overload determination result is determined to be overload.

[0054] Furthermore, preset temperature difference thresholds, preset strain difference thresholds, and preset local discharge flow rates are set. When the temperature difference of at least one temperature data combination exceeds the corresponding threshold, or / and the strain difference of at least one strain data combination exceeds the corresponding threshold, it indicates that there is significant spatial heterogeneity in the temperature and / or strain distribution, indicating the presence of a local anomaly. Or / and, when the local discharge current data exceeds the preset local discharge flow rate, it indicates the presence of a local discharge anomaly, and the environment can be determined to be overloaded. Therefore, it can be understood that only when each temperature difference in the temperature data combination is less than or equal to the preset temperature difference threshold, each strain difference in the strain data combination is less than or equal to the preset strain difference threshold, and the local discharge current data is less than or equal to the preset local discharge flow rate, the environmental overload determination result is not overloaded. In all other cases, the environmental overload determination result is overloaded.

[0055] In one embodiment, in the single chip computer program, the preset temperature difference threshold is set to 5°C, the preset strain difference threshold is set to 150με, and the preset local discharge flow rate is set to 10pC. For the example in step 201, the temperature difference ΔT 23 =7°C, which exceeds the preset temperature difference threshold of 5°C. Therefore, according to step 202, at least one temperature data combination has a temperature difference greater than the preset temperature difference threshold, and the environmental overload determination result is directly determined to be overload. For another example, assuming that the temperature difference does not exceed the threshold, but the strain difference Δε 12 =200με, exceeding the preset strain difference threshold of 150με, it is also determined to be overloaded; or the partial discharge current data is 12pC, exceeding 10pC, it is also determined to be overloaded; even when multiple of the temperature difference, strain difference and partial discharge current data exceed the threshold at the same time, it is also determined to be overloaded.

[0056] In step 203, if the temperature difference of each temperature data combination is less than or equal to the preset temperature difference threshold, and the strain difference of each strain data combination is less than or equal to the preset strain difference threshold, and the partial discharge current data is less than or equal to the preset partial discharge flow rate, then an environmental overload determination is performed based on the deviation rate of the three sets of temperature data, the three sets of strain data, and the partial discharge current data to determine the environmental overload determination result.

[0057] Furthermore, if the temperature difference of each temperature data combination is less than or equal to the preset temperature difference threshold, and the strain difference of each strain data combination is less than or equal to the preset strain difference threshold, and the partial discharge current data is less than or equal to the preset partial discharge flow, then the deviation rate of the three sets of temperature data, the three sets of strain data and the partial discharge current data is calculated, and the environmental overload judgment is performed based on the deviation rate of the three sets of temperature data, the three sets of strain data and the partial discharge current data to determine the environmental overload judgment result, as shown in steps 2031 to 2034.

[0058] By calculating temperature and strain differences, the embodiments of the present invention can sensitively capture the unevenness of temperature and strain distribution inside the cable terminal. This unevenness is often an early sign of local faults (such as poor contact and stress concentration). Therefore, through cross-analysis of multi-dimensional data, the operating status of the cable terminal can be more accurately assessed, and the risk of environmental overload can be discovered in advance. The probability of terminal insulation failure or explosion caused by abnormal internal status of the vehicle-mounted cable terminal can be effectively reduced, thereby avoiding the occurrence of parking and power outage accidents, and improving the long-term operational reliability of cable accessories.

[0059] In one embodiment, steps 2031 to 2034 are described as follows:

[0060] Step 2031: Construct three temperature-strain data combinations based on the three sets of temperature data and the three sets of strain data. The first temperature-strain data combination is the temperature data of the thermocouple at 0° and the strain data of the full-bridge strain gauge at 60°. The second temperature-strain data combination is the temperature data of the thermocouple at 120° and the strain data of the full-bridge strain gauge at 180°. The third temperature-strain data combination is the temperature data of the thermocouple at 240° and the strain data of the full-bridge strain gauge at 300°.

[0061] Optionally, based on the spatial layout of the cable terminal sensors, the temperature and strain data at specific angular positions are paired to form physically correlated combinations. 0° and 60°, 120° and 180°, and 240° and 300° are distributed at 60° intervals on the circumference. This pairing method can reflect the temperature-strain coupling relationship at different orientations of the cable terminal, facilitating the analysis of stress-temperature interactions in local areas. Therefore, three temperature-strain data combinations are constructed based on the three sets of temperature data and three sets of strain data. The first temperature-strain data combination consists of the temperature data from the thermocouple at 0° and the strain data from the full-bridge strain gauge at 60°. The second temperature-strain data combination consists of the temperature data from the thermocouple at 120° and the strain data from the full-bridge strain gauge at 180°. The third temperature-strain data combination consists of the temperature data from the thermocouple at 240° and the strain data from the full-bridge strain gauge at 300°.

[0062] In one embodiment, the collected temperature data are: thermocouple at 0°: T0=78°C, thermocouple at 120°: T 120 =82℃, thermocouple at 240°: T 240 =75℃.

[0063] Strain data: Full-bridge strain gauge at 60°: ε 60 =650με, full-bridge strain gauge at 180°: ε 180 =700με, full-bridge strain gauge at 300°: ε 300 =580με.

[0064] The MCU builds three combinations according to the position correspondence: The first combination: (T0, ε 60 ) = (78 ° C, 650 μ ε), the second combination: (T 120 , ε 180 ) = (82 ° C, 700 μ ε), the third combination: (T 240 , ε 300 ) = (75℃, 580με).

[0065] Step 2032 : determining a temperature deviation rate and a strain deviation rate based on the temperature data and the strain data in each temperature-strain data combination, and determining a partial discharge current deviation rate based on the partial discharge current data.

[0066] Furthermore, for each temperature-strain combination, the deviation rate of temperature and strain relative to the normal reference value is calculated, along with the deviation rate of the partial discharge current. The deviation rate quantifies the degree of deviation from the normal state using relative error. The reference values ​​for temperature and strain are set based on the cable terminal material properties and operational experience, while the reference value for partial discharge current is determined based on insulation electrical performance standards.

[0067] In this embodiment, the normal reference value is set as: temperature reference value: T ref =70℃, strain reference value: ε ref =500με, partial discharge current reference value: I ref =5pC.

[0068] Calculate the temperature deviation rate for each combination:

[0069] First combination: R(T0)=|78-70| / 70×100%≈11.43%.

[0070] Second combination: R (T 120 )=|82-70| / 70×100%≈17.14%.

[0071] The third combination: R (T 240)=|75-70| / 70×100%≈7.14%.

[0072] Calculate the strain deviation rate for each combination:

[0073] The first combination: R (ε 60 )=|650-500| / 500×100%=30%.

[0074] Second combination: R (ε 180 )=|700-500| / 500×100%=40%.

[0075] The third combination: R (ε 300 )=|580-500| / 500×100%=16%.

[0076] Calculate the partial discharge current deviation rate:

[0077] Assuming the partial discharge current I=8pC, R I =8 / 5×100%=160%.

[0078] Step 2033: If there is at least one temperature-strain data combination in which the temperature deviation rate is greater than the temperature deviation threshold, or / and the strain deviation rate is greater than the strain deviation threshold, or / and the partial discharge current deviation rate is greater than the partial discharge current deviation threshold, then the environmental overload determination result is determined to be overload.

[0079] Furthermore, the temperature deviation threshold, strain deviation threshold and partial discharge current deviation threshold are set. In the embodiment of the present invention, the threshold setting needs to comprehensively consider the material tolerance limit and the operation safety margin. For example, the temperature deviation threshold can be set to 20% (corresponding to a change of ±14°C), the strain deviation threshold is set to 35% (corresponding to a change of ±175με), and the partial discharge deviation threshold is set to 150% (corresponding to a change of ±7.5pC).

[0080] Furthermore, when the temperature deviation rate of at least one temperature-strain data combination is greater than the temperature deviation threshold or / and the strain deviation rate is greater than the strain deviation threshold, or / and the partial discharge current deviation rate is greater than the partial discharge current deviation threshold, the environmental overload determination result is determined to be overload.

[0081] In one embodiment, the temperature deviation threshold: R (T th ) = 20%, strain deviation threshold: R (ε th ) = 35%, partial discharge deviation threshold: R (I th ) = 150%.

[0082] In the example of step 2032: the first combined strain deviation rate R (ε 60 ) = 30% < 35%, temperature deviation rate R (T0) = 11.43% < 20%; the second combination strain deviation rate R (ε180 ) = 40%>35%, triggering the strain deviation overload condition, partial discharge deviation rate R I =160%>150%, and the partial discharge overload condition is triggered at the same time.

[0083] Therefore, according to step 2033, there is at least one combination of strain deviation rate exceeding the threshold value, and the partial discharge deviation rate exceeds the threshold value, and the environmental overload determination result is determined to be overload.

[0084] In step 2034, if the temperature deviation rate in each temperature-strain data combination is less than or equal to the temperature deviation threshold, the strain deviation rate is less than or equal to the strain deviation threshold, and the partial discharge current deviation rate is less than or equal to the partial discharge current deviation threshold, then based on the change direction of the temperature data and strain data in different temperature-strain data combinations, an environmental overload determination result is determined.

[0085] Furthermore, if the temperature deviation rate in each temperature-strain data combination is less than or equal to the temperature deviation threshold, the strain deviation rate is less than or equal to the strain deviation threshold, and the partial discharge current deviation rate is less than or equal to the partial discharge current deviation threshold, then the direction of change of temperature and strain in different combinations (simultaneous increase, simultaneous decrease, or divergent changes) is analyzed to determine whether there is a potential stress-temperature coupling anomaly. It should be noted that during normal operation of the cable terminal, changes in temperature and strain should conform to the physical laws of thermal expansion and contraction of materials. Any abnormal change direction (such as increasing temperature and decreasing strain, or vice versa) may indicate internal structural damage or stress relaxation, requiring further assessment of overload risk. Therefore, the environmental overload determination result is determined based on the direction of change of temperature and strain data in different temperature-strain data combinations, as specifically described in steps 20341 to 20343.

[0086] The embodiment of the present invention forms a hierarchical judgment logic from deviation rate threshold judgment to change direction consistency analysis, which not only covers the rapid identification of significant anomalies, but also captures progressive and hidden faults through physical law consistency checks, improves early warning capabilities, and effectively reduces the probability of terminal insulation failure or explosion incidents caused by abnormal internal states of vehicle-mounted cable terminals, avoids the occurrence of parking and power outages, and improves the long-term operation reliability of cable accessories.

[0087] In one embodiment, steps 20341 to 20343 are described as follows:

[0088] Step 20341 : determining the temperature data change direction and the temperature deviation change direction based on the temperature data in different temperature-strain data combinations, and determining the strain data change direction and the strain deviation change direction based on the strain data in different temperature-strain data combinations.

[0089] Optionally, the direction of data change can be determined by comparing the temperature / strain data from different temperature / strain data combinations with reference values ​​and historical data. The trend of the temperature / strain deviation rate is analyzed to determine the direction of deviation change. The first and second angle change directions are the predetermined regular directions of the angles at the thermocouple and full-bridge strain gauge locations, respectively, and are used to determine whether the temperature / strain changes conform to the spatial distribution pattern.

[0090] In one embodiment, the position angles of the thermocouple are 0°, 120°, and 240°, and the first angle change direction is the angle increasing direction (0°→120°→240°); the position angles of the full-bridge strain gauge are 60°, 180°, and 300°, and the second angle change direction is the angle increasing direction (60°→180°→300°).

[0091] Temperature reference value T ref =70℃, strain reference value ε ref =500με.

[0092] The temperature data of the thermocouple in the last sampling period is T 0-prev =72℃ (0° position), T 120-prev =75°C (120° position), T 240-prev =73°C (240° position), the strain data of the full-bridge strain gauge in the previous sampling cycle is ε 60-prev =580με (60° position), ε 180-prev =600με (180° position),ε 300-prev =560με (300° position).

[0093] The temperature data collected by the thermocouple in the current sampling period is: T0 = 78 ° C (0 ° position), T 120 =82°C (120° position), T 240 =85°C (240° position). The strain data collected by the full-bridge strain gauge in the current sampling period is: ε 60 =650με (60° position), ε 180 =700με (180° position), ε 300 =750με (300° position).

[0094] Determine the direction of temperature data change:

[0095] Calculate the difference between the current temperature and the temperature in the previous cycle:

[0096] ΔT0=T0-T 0-prev =78-72=+6℃ (temperature increase), ΔT 120 =T 120 -T 120-prev=82-75=+7℃ (temperature increase), ΔT 240 =T 240 -T 240-prev =85-73=+12℃ (temperature rise).

[0097] Temperature data change direction: In the first angle change direction (0°→120°→240°), the temperature shows an increasing trend, and the change direction is "increasing".

[0098] Determine the direction of temperature deviation change:

[0099] Calculate the difference between the current temperature deviation and the temperature deviation of the previous cycle:

[0100] Temperature deviation of the previous cycle: T 0-prev -T ref =72-70=+2℃, T 120-prev -T ref =75-70=+5℃, T 240-prev -T ref =73-70=+3℃.

[0101] Current temperature deviation: T0-T ref =78-70=+8℃, T 120 -T ref =82-70=+12℃, T 240 -T ref =85-70=+15℃.

[0102] Deviation change: Δ(T0-T 0-prev ) = 8-2 = +6 ° C, Δ (T 120 -T 120-prev ) = 12-5 = +7 ° C, Δ (T 240 -T 240-prev )=15-3=+12℃.

[0103] Temperature deviation change direction: In the first angle change direction, the temperature deviation shows an increasing trend, and the change direction is "increasing".

[0104] Determine the direction of change of strain data:

[0105] Calculate the difference between the current strain and the strain of the previous cycle: Δε 60 =ε 60 -ε 60-prev =650με-580με=+70με (increase), Δε 180 =ε 180 -ε 180-prev =700με-600με=+100με (increase), Δε 300 =ε 300-ε 300-prev =750με-560με=+190με (increase).

[0106] Strain data change direction: In the second angle change direction (60°→180°→300°), the strain shows an increasing trend, and the change direction is "increasing".

[0107] Determine the direction of strain deviation change:

[0108] Calculate the difference between the current strain deviation and the strain deviation of the previous cycle:

[0109] Strain deviation of the previous cycle: ε 60-prev -ε ref =580με-500με=+80με,ε 180-prev -ε ref =600με-500με=+100με,ε 300-prev -ε ref =560με-500με=+60με.

[0110] Current strain deviation: ε 60 -ε ref =650με-500με=+150με,ε 180 -ε ref =700με-500με=+200με,ε 300 -ε ref =750με-500με=+250με.

[0111] Deviation change: Δ(ε 60 -ε 60-prev )=150με-80με=+70με, Δ(ε 180 -ε 180-prev )=200με-100με=+100με, Δ(ε 300 -ε 300-prev )=250με-60με=+190με.

[0112] Strain deviation change direction: In the second angle change direction, the strain deviation shows an increasing trend, and the change direction is "increasing".

[0113] Step 20342: If the temperature data change direction and the temperature deviation change direction are both consistent with the first angle change direction of the thermocouple's position angle, and the strain data change direction and the strain deviation change direction are both consistent with the second angle change direction of the full-bridge strain gauge's position angle, then it is determined that the environmental overload judgment result is not overloaded.

[0114] Furthermore, when the direction of change of the temperature data and the direction of change of the temperature deviation are consistent with the first angle change direction of the position angle of the thermocouple, and the direction of change of the strain data and the direction of change of the strain deviation are consistent with the second angle change direction of the position angle of the full-bridge strain gauge, it means that the changes in temperature and strain conform to the normal spatial distribution law, the operating status of the cable terminal is normal, and the environmental overload judgment result is determined to be no overload.

[0115] Continuing with the embodiment of step 20341 above, the temperature data change direction in the first angular change direction (0°→120°→240°) is "increasing," consistent with the first angular change direction. The temperature deviation change direction in the first angular change direction is "increasing," consistent with the first angular change direction. The strain data change direction in the second angular change direction (60°→180°→300°) is "increasing," consistent with the second angular change direction. The strain deviation change direction in the second angular change direction is "increasing," consistent with the second angular change direction. Therefore, based on the data change direction and deviation change direction in step 20342, the environmental overload determination result is determined to be negative.

[0116] Step 20343: If the temperature data change direction or / and the temperature deviation change direction are inconsistent with the first angle change direction, or / and the strain data change direction or / and the strain deviation change direction are inconsistent with the second angle change direction, then determine that the environmental overload determination result is overloaded.

[0117] Furthermore, if the direction of change of the temperature data or the direction of change of the temperature deviation is inconsistent with the direction of change of the first angle, or / and, the direction of change of the strain data or the direction of change of the strain deviation is inconsistent with the direction of change of the second angle, it means that the change of temperature or strain does not conform to the normal spatial distribution law, and there may be local abnormalities, such as poor contact, stress concentration, etc., so the environmental overload judgment result is determined to be overload.

[0118] In one embodiment, another set of data: the current temperature data of the thermocouple position angles 0°, 120°, and 240° are T0=80°C, T 120 =75℃、T 240 =78℃.

[0119] The temperature data of the thermocouple in the last sampling period is T 0-prev =75℃ (0° position), T 120-prev =70°C (120° position), T 240-prev =72°C (240° position).

[0120] The current strain data of the full-bridge strain gauge at the position angles of 60°, 180°, and 300° is ε 60 =700με、ε 180=650με、ε 300 =600με.

[0121] The strain data of the full-bridge strain gauge in the previous sampling period is ε 60-prev =650με (60° position), ε 180-prev =600με (180° position),ε 300-prev =550με (300° position).

[0122] Determine the direction of temperature data change: ΔT0=80-75=+5℃ (increase), ΔT 120 =75-70=+5℃ (increase), ΔT 240 =78-72=+6℃ (increase).

[0123] The change direction of the temperature data is "increasing" in the change direction of the first angle, which is consistent with the change direction of the first angle.

[0124] Determine the direction of temperature deviation change:

[0125] Temperature reference value T ref =70℃.

[0126] Temperature deviation of the previous cycle: T 0-prev -T ref =5℃, T 120-prev -T ref =0℃, T 240-prev -T ref =2℃.

[0127] Current temperature deviation: T0-T ref =10℃, T 120 -T ref =5℃, T 240 -T ref =8℃.

[0128] Deviation change: Δ(T0-T 0-prev ) = 5°C, Δ(T 120 -T 120-prev ) = 5°C, Δ(T 240 -T 240-prev )=6℃.

[0129] The temperature deviation change direction in the first angle change direction (0°→120°→240°) is 5°C, 5°C, and 6°C, showing an increasing trend, which is consistent with the first angle change direction.

[0130] Determine the direction of change of strain data:

[0131] Δε 60 =700με-650με=+50με (increase), Δε180 =650με-600με=+50με (increase), Δε 300 =600με-550με=+50με (increase).

[0132] The change direction of the strain data is "increasing" in the change direction of the second angle, which is consistent with the change direction of the second angle.

[0133] Determine the direction of strain deviation change:

[0134] Strain reference value ε ref =500με.

[0135] Strain deviation of the previous cycle: ε 60-prev -ε ref =150με,ε 180-prev -ε ref =100με,ε 300-prev -ε ref =50με.

[0136] Current strain deviation: ε 60 -ε ref =200με,ε 180 -ε ref =150με,ε 300 -ε ref =100με.

[0137] Deviation change: Δ(ε 60 -ε 60-prev ) = 50με, Δ(ε 180 -ε 180-prev ) = 50με, Δ(ε 300 -ε 300-prev ) = 50με.

[0138] The strain deviation changes in the second angular direction (60° → 180° → 300°) are 50 με, 50 με, and 50 με, respectively. Although these values ​​are increasing, the angular direction (60° → 180° → 300°) indicates that the strain deviation should normally show a regular pattern (such as increasing or decreasing) as the angle increases. However, the fact that the deviation changes in these values ​​are the same here suggests an anomaly. However, according to the judgment criteria in step 20343, as long as the strain deviation changes in the same direction as the second angular direction, the strain deviation is increasing, which is consistent with the second angular direction. Therefore, an overload is not currently determined.

[0139] Let’s assume another situation:

[0140] Current temperature data T at a 240° angle at the thermocouple location 240=70℃, the last cycle T 240-prev =75℃, ΔT 240 =70-75=-5℃ (temperature drops).

[0141] The change direction of other temperature data is increasing in the change direction of the first angle, while the temperature at the 240° position decreases, resulting in the temperature data change direction being inconsistent with the change direction of the first angle.

[0142] According to step 20343, the change direction of the temperature data is inconsistent with the change direction of the first angle, and the environmental overload determination result is determined to be overload.

[0143] The embodiment of the present invention combines spatial distribution patterns and dynamic change trends to determine environmental overload, which can more accurately determine whether the environment is overloaded, reduce misjudgments and missed judgments, and improve the accuracy of overload judgments.

[0144] In one embodiment, steps 401 to 404 are described as follows:

[0145] Step 401 : determining the insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level respectively based on the insulation thermal fatigue damage data, the insulation creep data, and the insulation electrical performance data.

[0146] Optionally, the insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data are compared with preset grading thresholds to determine the corresponding insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level. The grading in this embodiment of the present invention is based on the aging characteristics of the insulation material and the operating experience of the cable terminal, dividing the insulation status into multiple levels.

[0147] In one embodiment, the insulation thermal fatigue damage data D heat =0.6, insulation creep data D creep =0.5, insulation electrical performance data D electric =0.3.

[0148] Set the threshold for grading (5 levels in total, the higher the level, the more severe the degradation):

[0149] Insulation thermal fatigue damage level threshold: [0, 0.2) is level 1, [0.2, 0.4) is level 2, [0.4, 0.6) is level 3, [0.6, 0.8) is level 4, and [0.8, 1.0] is level 5.

[0150] Insulation creep level threshold: [0, 0.15) is level 1, [0.15, 0.35) is level 2, [0.35, 0.55) is level 3, [0.55, 0.75) is level 4, and [0.75, 1.0] is level 5.

[0151] Insulation electrical performance level threshold: [0, 0.2) is level 1, [0.2, 0.4) is level 2, [0.4, 0.6) is level 3, [0.6, 0.8) is level 4, and [0.8, 1.0] is level 5.

[0152] Determine the insulation thermal fatigue damage level:

[0153] D heat =0.6, which is in the interval [0.6, 0.8), so the insulation thermal fatigue damage level is level 4.

[0154] Determine the insulation creep rating:

[0155] D creep =0.5, which is in the interval [0.35, 0.55), so the insulation creep grade is level 3.

[0156] Determine the insulation electrical performance level:

[0157] D electric =0.3, which is in the interval [0.2, 0.4), so the insulation electrical performance level is level 2.

[0158] Step 402: Establish a three-dimensional degradation mapping space with the insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level as coordinate axes, and map the insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level to coordinate points in the three-dimensional degradation mapping space to obtain a degradation intensity vector.

[0159] Furthermore, a three-dimensional degradation mapping space is established with the insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level as coordinate axes. The insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level are mapped to a coordinate point in the three-dimensional degradation mapping space to obtain a degradation intensity vector. The direction and length of the degradation intensity vector reflect the multi-dimensional characteristics of cable terminal insulation degradation. The degradation intensity vector can be expressed as:

[0160]

[0161] in, are the unit vectors of the three coordinate axes, H is the grade value of the insulation thermal fatigue damage grade, C is the grade value of the insulation creep grade, and E is the grade value of the insulation electrical performance grade.

[0162] In this embodiment, a three-dimensional coordinate system is established: the x-axis represents insulation thermal fatigue damage level (level 1-5), the y-axis represents insulation creep level (level 1-5), and the z-axis represents insulation electrical performance level (level 1-5).

[0163] Mapping coordinate points:

[0164] According to the result of step 401 , the insulation thermal fatigue damage level is level 4, the insulation creep level is level 3, and the insulation electrical performance level is level 2, so the coordinate point mapped into the three-dimensional space is (4, 3, 2).

[0165] Construct the degradation intensity vector:

[0166] The degradation intensity vector points from the origin (0, 0, 0) to the coordinate point (4, 3, 2), which is expressed as:

[0167]

[0168] Step 403 : construct a second-order degradation gradient tensor based on the first-order gradients of the insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level to the degradation strength vector, and the mixed second-order gradients of the insulation thermal fatigue damage level and insulation creep level to the degradation strength vector.

[0169] Furthermore, the first-order gradients of the insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level with respect to the degradation intensity vector are calculated, as well as the mixed second-order gradients of the insulation thermal fatigue damage level and insulation creep level with respect to the degradation intensity vector. A second-order degradation gradient tensor is constructed based on the first-order gradients and the mixed second-order gradients. In this embodiment, the second-order degradation gradient tensor G can be expressed as:

[0170]

[0171] in, represents the first-order gradient of the insulation thermal fatigue damage level to the degradation intensity vector, Represents the first-order gradient of insulation creep grade to degradation strength vector, Represents the first-order gradient of the insulation electrical performance level to the degradation intensity vector, Represents the mixed second-order gradient of insulation thermal fatigue damage level and insulation creep level to degradation strength vector.

[0172] Step 404 : determining the level interaction coefficients between any two levels of the insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level based on the second-order degradation gradient tensor, and determining the degradation grade based on the level interaction coefficients.

[0173] Furthermore, the level interaction coefficient between the insulation thermal fatigue damage level and the insulation creep level is calculated based on the second-order degradation gradient tensor. , the level interaction coefficient between insulation thermal fatigue damage level and insulation electrical performance level , the grade interaction coefficient between insulation creep grade and insulation electrical performance grade , the calculation formula of the level interaction coefficient is as follows:

[0174]

[0175] Among them, × represents the vector cross product, G 11 is the (1, 1) element of the second-order degraded gradient tensor, i.e. , G 12 is the (1, 2) element of the second-order degraded gradient tensor G, that is , G 21 is the (2, 1) element of the second-order degraded gradient tensor G, that is , G 22 is the (2, 2) element of the second-order degraded gradient tensor G, that is .

[0176] Furthermore, the degradation level is determined according to the grade interaction coefficient, as specifically described in the process from step 4041 to step 4044 .

[0177] The embodiment of the present invention not only takes into account the current degradation level, but also analyzes the degradation trend and interaction through the second-order degradation gradient tensor, which can detect potential accelerated degradation risks in advance and has a stronger fault warning capability, thereby effectively reducing the probability of terminal insulation failure or explosion caused by abnormal internal state of the on-board cable terminal, avoiding the occurrence of parking and power outage accidents, solving the problem of being unable to monitor in real time and comprehensively, and improving the long-term operation reliability of cable accessories.

[0178] In one embodiment, steps 4041 to 4044 are described as follows:

[0179] In step 4041, a degradation transmission coupling network is established using the insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level as network nodes and the level interaction coefficients between each level as edge weights. The degradation transmission coupling network is symmetrical and has zero diagonal elements.

[0180] Optionally, a degradation transmission coupling network is established with the insulation thermal fatigue damage level, insulation creep level, and insulation electrical performance level as network nodes and the level interaction coefficients between any two levels as edge weights. The degradation transmission coupling network is symmetrical and the diagonal elements are zero. Therefore, in this embodiment, the degradation transmission coupling network is:

[0181]

[0182] The degraded transmission coupling network of the embodiment of the present invention embodies a bidirectional interactive relationship between levels.

[0183] Step 4042: Determine the degradation propagation energy between the two levels based on the modulus of the degradation intensity vector, the level interaction coefficients of the two levels in the degradation transmission coupling network, and the level values ​​corresponding to the two levels.

[0184] Furthermore, the degradation propagation energy between two levels is determined based on the modulus of the degradation intensity vector, the level interaction coefficient of each level in the degradation transmission coupling network, and the level value corresponding to each level. Among them, the degradation propagation energy between the insulation thermal fatigue damage level and the insulation creep level is E HC The degradation propagation energy between the insulation thermal fatigue damage level and the insulation electrical performance level is E HE The degradation propagation energy between the insulation creep grade and the insulation electrical performance grade is E CE , the specific calculation formula is:

[0185]

[0186] is the modulus of the degradation intensity vector, reflecting the overall degradation degree.

[0187] Step 4043: Determine the path with the largest degradation propagation energy as the degradation dominant path, and determine the dominant path factor based on the degradation propagation energy of the degradation dominant path and the degradation propagation energy between any two levels.

[0188] Furthermore, the degradation propagation energy between two levels is compared to determine the degradation dominant path. In the embodiment of the present invention, if E HC ≥E HE And E HC ≥E CE , then the dominant degradation path is insulation thermal fatigue-insulation creep; if E HE ≥E HC And E HE ≥E CE , then the dominant degradation path is insulation thermal fatigue-insulation electrical performance; otherwise, the dominant degradation path is insulation creep-insulation electrical performance. Therefore, it can be understood that the path corresponding to the maximum degradation propagation energy is determined as the dominant degradation path.

[0189] Furthermore, the dominant path factor is determined based on the degradation propagation energy of the dominant degradation path and the degradation propagation energy between two levels. In this embodiment, the dominant degradation path is insulation thermal fatigue-insulation creep, and the dominant path factor is

[0190] Step 4044, determining the degradation level value based on the insulation thermal fatigue damage level, insulation creep level, insulation electrical performance level and dominant path factor, and determining the degradation level based on the size relationship between the degradation level value and the preset level threshold.

[0191] Furthermore, the degradation level value is determined based on the insulation thermal fatigue damage level, insulation creep level, insulation electrical performance level and dominant path factor. For insulation thermal fatigue-insulation creep as the dominant degradation path, the specific calculation formula for the degradation level value is:

[0192] Among them, a, b, c, and d are empirical coefficients, which are determined according to the material properties and operating environment of the on-board cable terminal.

[0193] For insulation thermal fatigue-insulation electrical performance as the dominant degradation path, the specific calculation formula for the degradation level value is:

[0194]

[0195] For insulation creep-insulation electrical performance as the dominant degradation path, the specific calculation formula for the degradation level value is:

[0196]

[0197] Furthermore, the first degradation level is determined by mapping the degradation level value to a preset level threshold. In this embodiment, the thresholds are: L < 10 for level 1, 10 ≤ L < 20 for level 2, 20 ≤ L < 30 for level 3, 30 ≤ L < 40 for level 4, and L ≥ 40 for level 5. Therefore, the formula for the first degradation level is:

[0198]

[0199] The embodiment of the present invention not only takes into account the current degradation level, but also analyzes the degradation trend and interaction through the second-order degradation gradient tensor, which can detect potential accelerated degradation risks in advance and has a stronger fault warning capability, thereby effectively reducing the probability of terminal insulation failure or explosion caused by abnormal internal state of the on-board cable terminal, avoiding the occurrence of parking and power outage accidents, solving the problem of being unable to monitor in real time and comprehensively, and improving the long-term operation reliability of cable accessories.

[0200] In one embodiment, the multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal further includes:

[0201] Step 50: If the environmental overload determination result is no overload, then based on the three sets of temperature data, the three sets of strain data and the partial discharge current data, the thermal cumulative effect value, the cumulative strain energy value and the discharge energy cumulative value are determined.

[0202] Optionally, if the environmental overload determination is negative, further analysis of the cumulative effects of temperature, strain, and partial discharge current data is required. The thermal cumulative effect value reflects the long-term thermal aging effects of temperature on the insulation material; the cumulative strain energy value reflects the accumulated energy and damage to the insulation material under strain; and the cumulative discharge energy value indicates the cumulative electrical aging effects of partial discharge on the insulation material.

[0203] In an embodiment of the present invention, the thermal accumulation effect value is obtained by integrating the Arrhenius equation, the cumulative strain energy value is calculated by integrating the area under the strain-stress curve, and the discharge energy accumulation value is calculated by integrating the square of the partial discharge current. The calculation process will not be repeated in this embodiment of the present invention.

[0204] Step 60: If the heat accumulation effect value is greater than the preset heat accumulation threshold, or / and the accumulated strain energy value is greater than the accumulated strain threshold, or / and the accumulated discharge energy value is greater than the accumulated discharge energy threshold, then the degradation condition of the vehicle cable terminal is determined to be a severe degradation state.

[0205] Furthermore, preset thresholds are set for the thermal accumulation effect value, the cumulative strain energy value and the discharge energy accumulation value. When the thermal accumulation effect value is greater than the preset thermal accumulation threshold, or / and, the cumulative strain energy value is greater than the cumulative strain threshold, or / and, the discharge energy accumulation value is greater than the discharge energy accumulation threshold, that is, when any one or more cumulative values ​​exceed the corresponding threshold, it indicates that the insulating material has been severely damaged during long-term operation, and the degradation condition of the on-board cable terminal is determined to be a severely degraded state, wherein the threshold setting is based on the tolerance limit of the insulating material and the service life requirements of the cable terminal.

[0206] In one embodiment, a threshold is set: a preset heat accumulation threshold H th =1×10 9 , cumulative strain threshold U th =2×10 7 J, discharge energy accumulation threshold Q th =2×10 -4 J.

[0207] If the thermal cumulative effect value H=1.78×10 9 >H th =1×10 9 , the cumulative strain energy value U=3.11×10 7 J>U th =2×10 7 J, discharge energy accumulation value Q=3.11×10 -4 J>Q th =2×10 -4 J.

[0208] Therefore, according to step 60 , the thermal cumulative effect value, the cumulative strain energy value, and the cumulative discharge energy value all exceed corresponding thresholds, and it is determined that the degradation condition of the on-board cable terminal is a severe degradation state.

[0209] In step 70 , if the thermal accumulation effect value is less than or equal to the preset thermal accumulation threshold, the cumulative strain energy value is less than or equal to the cumulative strain threshold, and the discharge energy accumulation value is less than or equal to the discharge energy accumulation threshold, first-order change rates and second-order change rates of the thermal accumulation effect value, the cumulative strain energy value, and the discharge energy accumulation value within the preset time window are determined respectively.

[0210] Furthermore, if the thermal accumulation effect value is less than or equal to a preset thermal accumulation threshold, the cumulative strain energy value is less than or equal to the cumulative strain threshold, and the cumulative discharge energy value is less than or equal to the cumulative discharge energy threshold, the first-order rate of change (derivative) and second-order rate of change (second-order derivative) of the thermal accumulation effect value, cumulative strain energy value, and cumulative discharge energy value within a preset time window are calculated. The first-order rate of change reflects the speed of change of the cumulative value, while the second-order rate of change reflects the trend of the rate of change, which is used to determine whether degradation is accelerating.

[0211] Optionally, the embodiment of the present invention uses a central difference method to calculate the first-order derivative and a second-order central difference method to calculate the second-order derivative. The specific calculation process is not repeated here.

[0212] In step 80, if the first-order change rates of the thermal cumulative effect value, the cumulative strain energy value, and the cumulative discharge energy value are all less than or equal to the critical rate, and the second-order change rates of the thermal cumulative effect value, the cumulative strain energy value, and the cumulative discharge energy value are all less than or equal to the preset rate threshold, then it is determined that the degradation condition of the on-board cable terminal is normal.

[0213] Furthermore, a critical rate and a preset rate threshold are set. When the first-order change rates of the thermal cumulative effect value, the cumulative strain energy value and the discharge energy cumulative value are all less than or equal to the critical rate, and the second-order change rates of the thermal cumulative effect value, the cumulative strain energy value and the discharge energy cumulative value are all less than or equal to the preset rate threshold, it means that the cumulative value changes slowly and the trend is stable, and the degradation condition of the on-board cable terminal is determined to be normal.

[0214] In one embodiment, the critical rate v is set as follows: th =1×10 4 , preset rate threshold a th =5×10 -5 .

[0215] In the example of step 70, the first-order rate of change v of the heat accumulation effect value is calculated. H =9.26×10 3 <v th =1×10 4 , second-order rate of change aH =0<a th =5×10 -5 .

[0216] It is assumed that the first-order and second-order change rates of the accumulated strain energy value and the accumulated discharge energy value also meet the conditions.

[0217] Therefore, according to step 80, it is determined that the degradation condition of the vehicle-mounted cable terminal is a normal state.

[0218] Step 90: If the first-order change rate of one of the thermal cumulative effect value, the cumulative strain energy value, and the discharge energy cumulative value is greater than the critical rate or / and the second-order change rate is greater than the preset rate threshold, it is determined that the degradation condition of the vehicle cable terminal is slightly degraded.

[0219] Furthermore, when the first-order change rate of one of the thermal cumulative effect value, the cumulative strain energy value and the discharge energy cumulative value is greater than the critical rate or / and the second-order change rate is greater than the preset rate threshold, it indicates that the change rate of the cumulative value is abnormal, and there may be a potential trend of accelerated degradation, and the degradation condition of the on-board cable terminal is determined to be a slightly degraded state.

[0220] In one embodiment, the first-order rate of change v of the heat accumulation effect value is calculated. H =1.2×10 4 >v th =1×10 4 , the changing rates of the accumulated strain energy value and the accumulated discharge energy value meet the conditions.

[0221] Therefore, according to step 90 , there is a value whose first-order change rate is greater than the critical rate, and the degradation condition of the on-board cable terminal is determined to be a slightly degraded state.

[0222] Step 100: If the first-order change rate of at least two of the thermal cumulative effect value, the cumulative strain energy value, and the discharge energy cumulative value is greater than a critical rate or / and the second-order change rate is greater than a preset rate threshold, it is determined that the degradation condition of the vehicle cable terminal is a moderate degradation state.

[0223] Furthermore, when the first-order change rate of at least two values ​​among the thermal cumulative effect value, the cumulative strain energy value and the discharge energy cumulative value is greater than the critical rate or / and the second-order change rate is greater than the preset rate threshold, it indicates that the change rate of multiple cumulative values ​​is abnormal, the degradation acceleration trend is obvious, and the degradation condition of the on-board cable terminal is determined to be a moderate degradation state.

[0224] In one embodiment, the first-order rate of change v of the heat accumulation effect value is calculated. H =1.2×10 4 >v th =1×10 4, the second-order rate of change of the accumulated strain energy value a U =6×10 -5 >a th =5×10 -5 .

[0225] The rate of change of the accumulated discharge energy value satisfies the condition. Therefore, according to step 100, there are abnormalities in the rate of change of the two values, and the degradation condition of the vehicle cable terminal is determined to be a moderate degradation state.

[0226] It should be noted that, in the embodiment of the present invention, the degradation level of the severe degradation state is higher than the degradation level of the moderate degradation state, and the degradation level of the moderate degradation state is higher than the degradation level of the slightly degradation state.

[0227] The embodiment of the present invention takes into account the cumulative effects in long-term operation and can effectively evaluate the long-term reliability of cable terminals. It is suitable for scenarios such as vehicle-mounted cable terminals that require long-term continuous operation, improves the long-term operation reliability of cable accessories, and thus improves the safety and stability of the system.

[0228] Furthermore, the multi-dimensional interface stress monitoring device of the vehicle-mounted cable terminal provided by the present invention is described below. The multi-dimensional interface stress monitoring device of the vehicle-mounted cable terminal described below and the multi-dimensional interface stress monitoring method of the vehicle-mounted cable terminal described above can be referred to each other.

[0229] Optional, see Figure 5 , Figure 5 : is a structural diagram of a multi-dimensional interface stress monitoring device for a vehicle-mounted cable terminal provided by the present invention, and the multi-dimensional interface stress monitoring device for a vehicle-mounted cable terminal includes:

[0230] The data acquisition module 510 is used to collect temperature data, strain data, and partial discharge current data of the vehicle cable terminal through thermocouples and full-bridge strain gauges at the interface between the rigid support tube and the stress control tube of the vehicle cable terminal, as well as a high-frequency current transformer sleeved on the shielded lead wire. The thermocouples and full-bridge strain gauges are respectively arranged at 0°, 120°, and 240°, and at 60°, 180°, and 300° of the geometric circular area of ​​the interface.

[0231] An environmental overload determination module 520 is configured to perform an environmental overload determination based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data, and determine an environmental overload determination result;

[0232] The data query module 530 is configured to determine insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data and their corresponding insulation association tables if the environmental overload determination result is overload;

[0233] The monitoring and display module 540 is used to determine the degradation level of the vehicle-mounted cable terminal based on the insulation thermal fatigue damage data, the insulation creep data and the insulation electrical performance data, and display the corresponding information.

[0234] The embodiment of the present invention sets sensors at multiple key locations of the cable terminal to collect temperature data, strain data, and partial discharge current data in real time, thereby ensuring the comprehensiveness and accuracy of the acquired data and avoiding the limitations of a single monitoring method, thereby being able to fully and accurately grasp the operating status of the cable terminal. The collected data is further associated with the insulation association table to achieve a visual assessment of the insulation status of the cable terminal, overcoming the disadvantage of being unable to accurately judge the insulation status. Furthermore, through environmental overload judgment, abnormal conditions during the operation of the cable terminal can be discovered in a timely manner, avoiding further deterioration of the abnormal conditions, and improving the ability to prevent cable terminal failures, thereby effectively reducing the probability of terminal insulation failure or explosion events caused by abnormal internal conditions of the vehicle-mounted cable terminal, avoiding the occurrence of parking and power outages, solving the problem of being unable to conduct real-time and comprehensive monitoring, and improving the long-term operational reliability of cable accessories.

[0235] See also Figure 6 , Figure 6 This is a diagram of an embodiment of an electronic device provided by an embodiment of the present invention. Figure 6 As shown, an embodiment of the present invention provides an electronic device 600, including a memory 610, a processor 620, and a computer program 611 stored in the memory 610 and executable on the processor 620. When the processor 620 executes the computer program 611, the process from step 10 to step 40 is implemented.

[0236] See also Figure 7 , Figure 7 Detailed description of an embodiment of a computer-readable storage medium provided by an embodiment of the present invention. Figure 7 As shown, this embodiment provides a computer-readable storage medium 700 on which a computer program 611 is stored. When the computer program 611 is executed by a processor, the process from step 10 to step 40 is implemented.

[0237] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the multi-dimensional interface stress monitoring method of the vehicle cable terminal provided by the above methods. The multi-dimensional interface stress monitoring method of the vehicle cable terminal includes steps 10 to 40.

[0238] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0239] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0240] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal, characterized in that: include: Temperature data, strain data, and partial discharge current data of the on-board cable terminal are collected through thermocouples and full-bridge strain gauges at the interface between the rigid support tube and the stress control tube of the on-board cable terminal, as well as a high-frequency current transformer sleeved on the shielded lead-out wire; the thermocouples and full-bridge strain gauges are respectively arranged at 0°, 120°, and 240° positions, as well as at 60°, 180°, and 300° positions in the geometric circular area of ​​the interface; Performing an environmental overload judgment based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data, and determining an environmental overload judgment result; If the environmental overload determination result is overload, determining insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data and their corresponding insulation association tables; determining a degradation level of the vehicle-mounted cable terminal based on the insulation thermal fatigue damage data, the insulation creep data, and the insulation electrical performance data, and displaying corresponding information; Determining the degradation level of the vehicle-mounted cable terminal specifically includes: Determining an insulation thermal fatigue damage level, an insulation creep level, and an insulation electrical performance level, respectively, based on the insulation thermal fatigue damage data, the insulation creep data, and the insulation electrical performance data; Establishing a three-dimensional degradation mapping space with the insulation thermal fatigue damage level, the insulation creep level, and the insulation electrical performance level as coordinate axes, and mapping the insulation thermal fatigue damage level, the insulation creep level, and the insulation electrical performance level to coordinate points in the three-dimensional degradation mapping space to obtain a degradation intensity vector; Constructing a second-order degradation gradient tensor based on the first-order gradients of the insulation thermal fatigue damage level, the insulation creep level, and the insulation electrical performance level with respect to the degradation intensity vector, respectively, and a mixed second-order gradient of the insulation thermal fatigue damage level and the insulation creep level with respect to the degradation intensity vector; The level interaction coefficients between any two of the insulation thermal fatigue damage level, the insulation creep level, and the insulation electrical performance level are determined based on the second-order degradation gradient tensor, and the degradation grade is determined based on the level interaction coefficients.

2. The multi-dimensional interface stress monitoring method of a vehicle-mounted cable terminal according to claim 1, characterized in that: The performing of environmental overload determination based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data, and determining the environmental overload determination result, includes: For a temperature data combination of any two temperature data in the three sets of temperature data and a strain data combination of any two strain data in the three sets of strain data, determining a temperature difference value of each temperature data combination and a strain difference value of each strain data combination; If the temperature difference of at least one temperature data combination is greater than a preset temperature difference threshold, or / and, the strain difference of at least one strain data combination is greater than a preset strain difference threshold, or / and, the partial discharge current data is greater than a preset partial discharge flow rate, then the environmental overload determination result is determined to be overload; If the temperature difference of each temperature data combination is less than or equal to the preset temperature difference threshold, and the strain difference of each strain data combination is less than or equal to the preset strain difference threshold, and the partial discharge current data is less than or equal to the preset partial discharge flow, then an environmental overload judgment is performed based on the deviation rate of the three sets of temperature data, the three sets of strain data and the partial discharge current data to determine the environmental overload judgment result.

3. The multi-dimensional interface stress monitoring method of a vehicle-mounted cable terminal according to claim 2, characterized in that: The performing of environmental overload judgment based on the deviation rate of the three sets of temperature data, the three sets of strain data, and the partial discharge current data, and determining the environmental overload judgment result, includes: Constructing three temperature-strain data combinations based on the three sets of temperature data and the three sets of strain data; the first temperature-strain data combination is the temperature data of the thermocouple at 0° and the strain data of the full-bridge strain gauge at 60°; the second temperature-strain data combination is the temperature data of the thermocouple at 120° and the strain data of the full-bridge strain gauge at 180°; and the third temperature-strain data combination is the temperature data of the thermocouple at 240° and the strain data of the full-bridge strain gauge at 300°. Determining a temperature deviation rate and a strain deviation rate based on the temperature data and the strain data in each temperature-strain data combination, and determining a partial discharge current deviation rate based on the partial discharge current data; If there is at least one temperature-strain data combination in which the temperature deviation rate is greater than the temperature deviation threshold, or / and the strain deviation rate is greater than the strain deviation threshold, or / and the partial discharge current deviation rate is greater than the partial discharge current deviation threshold, then the environmental overload determination result is determined to be overload; If the temperature deviation rate in each temperature-strain data combination is less than or equal to the temperature deviation threshold and the strain deviation rate is less than or equal to the strain deviation threshold, and the partial discharge current deviation rate is less than or equal to the partial discharge current deviation threshold, then the environmental overload judgment result is determined based on the change direction of the temperature data and strain data in different temperature-strain data combinations.

4. The multi-dimensional interface stress monitoring method of a vehicle-mounted cable terminal according to claim 3, characterized in that: The determining of the environmental overload determination result based on the change direction of the temperature data and the strain data in different temperature-strain data combinations includes: Determining a temperature data change direction and a temperature deviation change direction based on the temperature data in the different temperature-strain data combinations, and determining a strain data change direction and a strain deviation change direction based on the strain data in the different temperature-strain data combinations; If the temperature data change direction and the temperature deviation change direction are both consistent with the first angle change direction of the thermocouple position angle, and the strain data change direction and the strain deviation change direction are both consistent with the second angle change direction of the full-bridge strain gauge position angle, then it is determined that the environmental overload determination result is not overloaded; If the temperature data change direction or / and the temperature deviation change direction are inconsistent with the first angle change direction, or / and, the strain data change direction or / and the strain deviation change direction are inconsistent with the second angle change direction, then the environmental overload judgment result is determined to be overloaded.

5. The multi-dimensional interface stress monitoring method of a vehicle-mounted cable terminal according to claim 1, characterized in that: The determining the degradation level based on the grade interaction coefficient includes: A degradation transmission coupling network is established with the insulation thermal fatigue damage level, the insulation creep level, and the insulation electrical performance level as network nodes and the level interaction coefficients between any two levels as edge weights; the degradation transmission coupling network is symmetrical and the diagonal elements are zero; Determining degradation propagation energy between two levels based on the modulus of the degradation intensity vector, the level interaction coefficients of the two levels in the degradation transmission coupling network, and the level values ​​corresponding to the two levels; Determining a path corresponding to the maximum degradation propagation energy as a degradation dominant path, and determining a dominant path factor based on the degradation propagation energy of the degradation dominant path and the degradation propagation energy between two levels; A degradation level value is determined based on the insulation thermal fatigue damage level, the insulation creep level, the insulation electrical performance level and the dominant path factor, and the degradation level is determined based on a magnitude relationship between the degradation level value and a preset level threshold.

6. The multi-dimensional interface stress monitoring method of a vehicle-mounted cable terminal according to claim 1, characterized in that: The multi-dimensional interface stress monitoring method of the vehicle-mounted cable terminal further includes: If the environmental overload determination result is no overload, determining a thermal cumulative effect value, a cumulative strain energy value, and a discharge energy cumulative value based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data, respectively; If the heat accumulation effect value is greater than a preset heat accumulation threshold, or / and, the accumulated strain energy value is greater than a accumulated strain threshold, or / and, the accumulated discharge energy value is greater than a accumulated discharge energy threshold, then the degradation condition of the on-board cable terminal is determined to be a severe degradation state; If the heat accumulation effect value is less than or equal to a preset heat accumulation threshold, the accumulated strain energy value is less than or equal to the accumulated strain threshold, and the accumulated discharge energy value is less than or equal to the accumulated discharge energy threshold, then determining a first-order rate of change and a second-order rate of change of the heat accumulation effect value, the accumulated strain energy value, and the accumulated discharge energy value within a preset time window, respectively; If the first-order change rate of each value is less than or equal to the critical rate, and the second-order change rate of each value is less than or equal to the preset rate threshold, then it is determined that the degradation condition of the on-board cable terminal is normal; If there is a value whose first-order change rate is greater than a critical rate or / and whose second-order change rate is greater than a preset rate threshold, it is determined that the degradation condition of the on-board cable terminal is a slightly degraded state; If there are at least two values ​​whose first-order change rate is greater than a critical rate or / and whose second-order change rate is greater than a preset rate threshold, it is determined that the degradation condition of the on-board cable terminal is a moderate degradation state; The degradation level of the severe degradation state is higher than that of the moderate degradation state, and the degradation level of the moderate degradation state is higher than that of the slightly degradation state.

7. The multi-dimensional interface stress monitoring method of a vehicle-mounted cable terminal according to claim 1, characterized in that: The insulation correlation table includes a temperature insulation correlation table, a strain insulation correlation table and a partial discharge insulation correlation table. The temperature insulation correlation table represents the correspondence between the thermal property values ​​and the insulation thermal fatigue damage conditions; the strain insulation correlation table represents the correspondence between the strain property values ​​and the insulation creep conditions; the partial discharge insulation correlation table represents the correspondence between the partial discharge flow and the insulation electrical performance conditions.

8. A multi-dimensional interface stress monitoring device for a vehicle-mounted cable terminal, characterized in that: A multi-dimensional interface stress monitoring method for a vehicle-mounted cable terminal as claimed in any one of claims 1 to 7; The multi-dimensional interface stress monitoring device of the vehicle-mounted cable terminal includes: a data acquisition module for collecting temperature data, strain data, and partial discharge current data of the on-board cable terminal through thermocouples and full-bridge strain gauges at the interface between the rigid support tube and the stress control tube of the on-board cable terminal, and a high-frequency current transformer sleeved on the shielded lead-out wire; the thermocouples and full-bridge strain gauges are respectively arranged at positions 0°, 120°, and 240°, and at positions 60°, 180°, and 300°, of the geometric circular area of ​​the interface; An environmental overload determination module is configured to determine an environmental overload determination based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data, and to determine an environmental overload determination result; a data query module, configured to determine insulation thermal fatigue damage data, insulation creep data, and insulation electrical performance data based on the three sets of temperature data, the three sets of strain data, and the partial discharge current data and their corresponding insulation association tables if the environmental overload determination result is overload; A monitoring and display module is used to determine the degradation level of the vehicle-mounted cable terminal based on the insulation thermal fatigue damage data, the insulation creep data and the insulation electrical performance data, and display corresponding information.

9. A non-transitory computer-readable storage medium storing a computer software program, wherein: When the computer software program is executed by a processor, the multi-dimensional interface stress monitoring method of the vehicle-mounted cable terminal according to any one of claims 1 to 7 is implemented.

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