Heat tracing cable insulation performance test method and system

Abstract

The invention relates to the technical field of electrical performance testing, in particular to a heat tracing cable insulation performance testing method and system, and the method comprises the steps: dividing a temperature rise stage according to the temperature change of an insulation layer between adjacent moments; obtaining an insulation coefficient according to the comparison condition of the insulation resistance values at the first moment and the last moment of each temperature rise stage; according to the insulation coefficient of the heat tracing cable, the temperature rise rate change values at all moments and the time duration of the temperature rise stage, insulation change parameters are obtained; obtaining a current change degree value according to the numerical value distribution condition of the characteristic current; according to the time duration, the current change degree value and the insulation change parameter of all the temperature rise stages, obtaining an insulation performance attenuation parameter of the heat tracing cable; and obtaining an insulation performance test result of the heat tracing cable according to the concentration degree of the numerical distribution of the insulation performance attenuation parameters of the heat tracing cable under all insulation performance detection. The accuracy of the insulation performance test of the heat tracing cable can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of electrical performance testing, and in particular to a method and system for testing the insulation performance of a heating cable. Background Art

[0002] Heating cable is a cable used to provide heat on the surface of pipelines, containers, equipment or building structures. It mainly prevents ice and condensation on the surface of pipelines and equipment, maintains temperature stability, or heats certain objects that require a specific temperature through the heat generated when the current passes through the cable. The insulation performance directly affects the safety and stability of the system.

[0003] Traditional heating cable insulation performance tests are mainly conducted at room temperature. However, heating cables need to be in a high temperature environment for a long time during use. Only testing the insulation performance of heating cables at room temperature or a certain fixed temperature cannot represent the insulation performance status of the heating cables under actual temperature change scenarios, resulting in inaccurate insulation performance test results of the heating cables. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a method and system for testing the insulation performance of a heating cable. The technical solutions adopted are as follows:

[0005] In a first aspect, an embodiment of the present application provides a method for testing insulation performance of a heating cable, the method comprising the following steps:

[0006] S1, real-time acquisition of characteristic current, insulation layer temperature and insulation resistance value of the heating cable during each insulation performance test;

[0007] S2, obtaining the temperature rise rate change value at each moment according to the temperature change of the insulation layer between adjacent moments; dividing the temperature rise stage according to the numerical distribution of the temperature rise rate change values ​​at consecutive moments;

[0008] S3, according to the comparison of the insulation resistance values ​​at the beginning and the end of each temperature rise stage, the insulation coefficient of the heating cable in each temperature rise stage is obtained; according to the insulation coefficient of the heating cable in each temperature rise stage, the temperature rise rate change value at all times and the time length of the temperature rise stage, the insulation change parameter of each temperature rise stage is obtained;

[0009] S4, according to the numerical distribution of characteristic current in each temperature rise stage, the current change degree value in each temperature rise stage is obtained; according to the time length, current change degree value and insulation change parameter of all temperature rise stages, the insulation performance attenuation parameter of the heating cable is obtained;

[0010] S5, obtaining the insulation performance test result of the heating cable according to the concentration degree of the numerical distribution of the insulation performance attenuation parameter of the heating cable under all insulation performance tests.

[0011] Further, obtaining the temperature rise rate change value at each moment according to the insulation layer temperature change between adjacent moments includes:

[0012] The temperature change rate at each moment is obtained according to the temperature difference of the insulation layer between adjacent moments; the difference between the temperature change rate at each moment and the next moment is used as the temperature rise rate change value at each moment.

[0013] Further, the temperature change rate at each moment is obtained according to the temperature difference between adjacent moments, including: recording the temperature change rate at the i-th moment as v i , Where t is the time interval between adjacent moments; w i+1 、w i are the insulation layer temperatures at the i+1th and ith moments respectively.

[0014] Furthermore, the temperature rise stages are divided according to the numerical distribution of the temperature rise rate change values ​​at consecutive moments, including:

[0015] A time period consisting of consecutive moments in which the normalized value of the temperature rise rate change value is less than a preset threshold is recorded as a temperature rise stage.

[0016] Furthermore, the method for obtaining the insulation coefficient of the heating cable at each temperature rise stage includes:

[0017] The ratio of the insulation resistance value at the last moment of the temperature rise stage to the insulation resistance value at the first moment of the temperature rise stage is calculated, and the normalized value of the ratio is used as the insulation coefficient of the heating cable in the temperature rise stage.

[0018] Furthermore, the method for obtaining the insulation change parameters at each temperature rise stage includes:

[0019]

[0020] Among them, g a is the insulation change parameter in the ath temperature rise stage; δ a is the insulation change parameter in the ath temperature rise stage; Δt a is the time length of the ath temperature rise stage; the time length is the time difference between the first and last moments of the temperature rise stage; v y ' is the change value of the temperature rise rate at the yth moment in the ath temperature rise stage; n is the number of moments included in the ath temperature rise stage.

[0021] Furthermore, the method for calculating the current change degree value in each temperature rise stage includes:

[0022] The maximum value of the characteristic current at all times during the detection process is obtained; the maximum mean value of the characteristic current at all times in the temperature rise stage is calculated; and the difference between the maximum value and the maximum mean value is used as the current change degree value in the temperature rise stage.

[0023] Furthermore, the method for obtaining the insulation performance attenuation parameter of the heating cable specifically includes:

[0024]

[0025] Among them, R is the insulation performance attenuation parameter of the heating cable, m is the number of temperature rise stages, τ a is the current change value in the ath temperature rise stage, Δt a is the duration of the ath temperature rise stage, g a is the insulation change parameter in the temperature rise stage, and softsign() uses the derivative function of the softsign function to normalize the result.

[0026] Further, the insulation performance test result of the heating cable is obtained according to the concentration degree of the numerical distribution of the insulation performance attenuation parameter of the heating cable under all insulation performance tests, including:

[0027] The insulation performance attenuation parameters of the heating cable under each insulation performance test are normalized to obtain a normalized value; the standard deviation of the normalized value of the heating cable under all insulation performance tests is calculated; if the standard deviation is less than a preset fluctuation threshold, the insulation performance of the heating cable is good; otherwise, the insulation performance of the heating cable is unqualified.

[0028] In a second aspect, an embodiment of the present application further provides a heating cable insulation performance testing system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, the steps of any one of the above-mentioned heating cable insulation performance testing methods are implemented.

[0029] This application has at least the following beneficial effects:

[0030] The present application analyzes the limitations of testing the insulation performance of heating cables at a fixed temperature, first analyzes the temperature factors that have a greater impact on the insulation performance in the application scenarios of heating cables, and in the process of heating the temperature of the heating cables, the rate of change of the temperature increase of the heating cables is different at different stages, and the temperature rise stages are divided according to the temperature changes in local time; further analyzes the situation in which the temperature changes affect the resistance of the heating cables and thus the insulation performance degradation caused by the process of converting electrical energy into thermal energy of the heating cables, and obtains the insulation coefficient by comparing the insulation resistance values ​​of the insulation layer of the heating cables before and after the temperature rise stage, reflecting the degree to which the insulation performance of the heating cables is affected by the temperature; comprehensively analyzes the changes in temperature and insulation coefficient in the temperature rise stage, and obtains the insulation change parameters to represent the insulation performance of each stage; finally, the insulation performance attenuation parameters of the heating cables are obtained by combining the time lengths of all temperature rise stages, the current change degree value, and the insulation coefficient change parameters, and considering the insulation performance attenuation phenomenon of the insulating materials during long-term use, the insulation performance attenuation parameters of the heating cable test samples are combined to obtain the insulation performance test results of the heating cables, thereby improving the accuracy of the insulation performance test of the heating cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 A flowchart of a method for testing insulation performance of a heating cable provided in one embodiment of the present application;

[0033] Figure 2 A schematic diagram of a curve showing how the insulation coefficient and characteristic current change with temperature, provided in one embodiment of the present application. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0036] The following is a detailed description of a method and system for testing the insulation performance of a heating cable provided by the present application in conjunction with the accompanying drawings.

[0037] See also Figure 1 , which shows a flow chart of the steps of a method for testing the insulation performance of a heating cable provided by an embodiment of the present application, the method comprising the following steps:

[0038] S1, real-time acquisition of characteristic current, insulation layer temperature and insulation resistance value of the heating cable during each insulation performance test.

[0039] A specific implementation scenario of the present application is a scenario in which the insulation performance of the heating cable is tested. During the insulation performance test of the heating cable, temperature changes have a certain impact on the insulation performance of the insulating material of the insulation layer, and there are errors in the test results of the insulation performance of the heating cable under a single temperature environment.

[0040] In view of the defect that only the current state test results are analyzed in the above-mentioned heating cable insulation performance test, the changes in insulation performance caused by temperature changes are not considered, resulting in inaccurate insulation performance test results. This embodiment simulates the scenario in which the insulation layer temperature rises due to the heating of the cable during operation, and performs the test, and monitors the cable data in real time, and then obtains the real insulation performance of the heating cable based on the monitoring data, thereby improving the test effect and accuracy of the insulation performance of the heating cable.

[0041] Therefore, this embodiment uses AC superposition technology to detect the insulation performance of the heating cable; first, ensure that the heating cable to be tested is in a power-off state, use a connecting wire to connect the output end of the signal generator to the shielding layer of the heating cable, and connect the input end of the current sensor to the cable to measure the characteristic current.

[0042] Place the heating cable in a heating device to simulate the temperature environment of the heating cable when it is working, gradually increase the temperature to increase the temperature of the heating cable, and record the temperature of the insulation layer. At the same time, use a megohmmeter to detect the insulation resistance value of the heating cable in real time during the AC superposition test to compare the impact of the voltage on the cable insulation layer.

[0043] The heating cable is tested, the monitored characteristic current I is recorded according to the detection time, and the heating cable to be detected is tested multiple times. In this embodiment, a total of 10 tests are performed.

[0044] S2, obtaining the temperature rise rate change value at each moment according to the temperature change of the insulation layer between adjacent moments; and dividing the temperature rise stage according to the numerical distribution of the temperature rise rate change values ​​at consecutive moments.

[0045] The conductive properties of insulating materials are mainly manifested as ionic conductivity. In ionic conduction, the current is generated by the directional movement of ions, which come from the crystalline lattice of the insulator. At room temperature, the number of ions is small, indicating poor conductivity and high insulation resistance. As the temperature rises, the thermal vibration of the insulator molecules increases, and more ions are separated from the lattice, resulting in increased conductivity, which in turn reduces the insulation resistance.

[0046] Heating cables use electric heat to replenish the heat lost by the heated body in the environment, thereby maintaining the medium in a certain temperature range. This is a form of electric energy utilization, which causes the insulation layer of the heating cable to be in a high temperature environment for a long time. Therefore, during the use of the heating cable, as the temperature of the surrounding environment increases, the insulation performance of the insulation layer will decrease. Therefore, the temperature change of the insulation layer of the heating cable in the temperature-raising environment is further analyzed.

[0047] As the ambient temperature of the heating cable increases, the temperature of the heating cable insulation layer increases, the characteristic current increases, and the insulation performance decreases. In order to determine the degree to which the insulation performance of the heating cable is affected by temperature, the characteristic current at adjacent moments is compared to analyze the changes in insulation performance.

[0048] As the temperature rises, the insulation properties of the insulation material change, causing the characteristic current monitored by the current sensor to increase as the insulation properties decrease. Since the insulation efficiency of the insulation layer is affected by temperature, when the temperature of the heating cable rises, the insulation properties of the heating cable decrease, increasing the amount of current passing through the insulation layer, further exacerbating the temperature rise. Therefore, in the process of the heating cable temperature rising, the rate of change of the heating cable temperature rise is different at different stages. The faster the temperature rises, the worse the insulation performance.

[0049] For the analysis of the temperature change state of the heating cable during the temperature rise process, the temperature rise process is divided into different stages according to the difference in temperature change rate, and the temperature insulation state parameters of different temperature rise stages are obtained according to the temperature rise time and temperature rise amplitude in each stage:

[0050] First, the temperature change rate at each moment is obtained according to the temperature change between different moments. The calculation formula for the temperature change rate at the i-th moment is: t is the time interval between adjacent moments; w i+1 、w i are the insulation layer temperatures at the i+1th and ith moments respectively.

[0051] Furthermore, by comparing the temperature rise rates at adjacent moments, the temperature rise rate change value v is obtained. i '=|v i -v i+1 |. The larger the value, the worse the insulation performance.

[0052] All the obtained temperature rise rate change values ​​v' are recorded, normalized by the MAX-MIN function, and the threshold is set to 0.6; the time period consisting of continuous moments when the normalized value of the temperature rise rate change value is less than the preset threshold is recorded as a temperature rise stage. For example, a group of normalized values ​​of the temperature rise rate change value is 0.3, 0.5, 0.6, 0.7, 0.4, 0.3, 0.4; there are two temperature rise stages: 0.3, 0.5; and 0.4, 0.3, 0.4.

[0053] S3, according to the comparison of the insulation resistance values ​​at the beginning and the end of each temperature rise stage, the insulation coefficient of the heating cable in each temperature rise stage is obtained; according to the insulation coefficient of the heating cable in each temperature rise stage, the change value of the temperature rise rate at all times and the time length of the temperature rise stage, the insulation change parameters of each temperature rise stage are obtained.

[0054] During use, the heating cable will continuously convert electrical energy into heat energy and release it to achieve the effect of clearing snow and ice. However, during the heating process, the outer material of the heating cable will gradually degrade due to the increase in temperature. Figure 2 The figure shows the curve diagram of the change of insulation coefficient and characteristic current with temperature, which shows that the insulation performance gradually decays and the characteristic current gradually increases due to the increase of temperature. Therefore, the test data of the heating cable under the state of temperature rise is first analyzed. After the heating cable is connected to the power supply, the current passes from one core through the conductive PTC material to the other core to form a loop. Since the insulation resistance value of the insulation layer of the heating cable is constantly changing due to the influence of voltage, the greater the voltage, the smaller the insulation resistance value, and the insulation resistance value is an important parameter to measure the insulation performance.

[0055] Therefore, by comparing the insulation resistance values ​​of the heating cable insulation layer before and after the temperature rise stage, the insulation coefficient of the heating cable can be obtained:

[0056]

[0057] Among them, δ is the insulation coefficient of the heating cable, Ω z ,Ω o They represent the insulation resistance values ​​at the last moment of the temperature rise stage and the first moment of the temperature rise stage respectively, and norm() is a linear normalization function. The smaller the insulation resistance value of the heating cable after the temperature rise stage is compared with that before the temperature rise stage, the poorer the insulation effect.

[0058] Furthermore, the state parameters of temperature rise change in different stages are different, which leads to changes in the insulation coefficient of the heating cable at different times, and it decreases with the actual temperature rise. Therefore, when analyzing the insulation state change parameters of the heating, it is necessary to analyze the changes in the insulation coefficient in the temperature rise stage. According to the insulation coefficient and temperature rise rate change values ​​of the heating cable in the temperature rise stage, the insulation change parameter g in the temperature rise stage is obtained:

[0059]

[0060] Among them, g a is the insulation change parameter in the ath temperature rise stage; δ a is the insulation change parameter in the ath temperature rise stage; Δt a is the duration of the ath temperature rise stage; specifically, it is the time difference between the first and last moments of the temperature rise stage; v y ' is the temperature rise rate change value at the yth moment in the ath temperature rise stage; n is the number of moments included in the ath temperature rise stage. Among them, It is the average change of the insulation coefficient of the heating cable during the temperature rise stage. Its product with the change value of the temperature rise rate represents the changing relationship between the insulation state and temperature. The larger the value is, the greater the insulation change parameter is during the temperature rise stage, and the worse the insulation performance is.

[0061] S4, according to the numerical distribution of characteristic current in each temperature rise stage, the current change degree value in each temperature rise stage is obtained; according to the time length, current change degree value and insulation change parameter of all temperature rise stages, the insulation performance attenuation parameter of the heating cable is obtained.

[0062] During the operation of the heating cable, when the power reaches the rated power, the temperature of the heating cable no longer increases, and the insulation layer is in a relatively stable temperature range. At this time, the maximum characteristic current I detected by the current sensor is max .

[0063] Furthermore, in different temperature rise stages, there is a maximum value of the characteristic current. Therefore, when analyzing the insulation performance parameters of the cable, it is necessary to obtain the current change value of each temperature rise stage. The current change value of the a-th temperature rise stage is τ a =I max -I' a ; Among them, I max is the maximum value of the characteristic current at all times during the detection process; I' a is the average of the maximum values ​​of the characteristic current at all moments in the ath temperature rise stage.

[0064] Furthermore, during the use of the heating cable, the rated voltage or fixed voltage is used for power output. With the long-term use of the heating cable, the insulation performance of the heating cable insulation layer decays, which causes additional loss of current during transmission and improves the temperature rise efficiency of the heating cable. According to the length of the temperature rise stage, combined with the current change degree value and the insulation coefficient change parameter, the insulation performance decay parameter R of the heating cable is obtained.

[0065]

[0066] Among them, m is the number of temperature rise stages, τ a is the current change value in the ath temperature rise stage, Δt a is the duration of the ath temperature rise stage, g a is the insulation change parameter in the temperature rise stage, and softsign() uses the derivative function of the softsign function to normalize the result. It is the rate of change of the current change degree in the temperature rise stage. The larger the value is, the more the insulation performance is affected by temperature. At this time, the larger the insulation change parameter in the temperature rise stage, the larger the insulation performance attenuation parameter is, and the worse the insulation performance is.

[0067] S5, obtaining the insulation performance test result of the heating cable according to the concentration degree of the numerical distribution of the insulation performance attenuation parameter of the heating cable under all insulation performance tests.

[0068] During long-term use, the insulation performance of the insulating material will gradually decrease, thus affecting the safety of the heating cable. Therefore, when testing and evaluating the insulation performance of the heating cable, it is necessary to consider the insulation performance attenuation phenomenon of the insulating material during long-term use. Therefore, the heating cable test samples are tested multiple times, and the insulation performance attenuation parameters of the heating cable are obtained using the above method for each test.

[0069] Finally, the insulation performance of the heating cable reflects the damage of the heating cable to the electric energy. If the insulation performance of the heating cable is stable, the insulation performance attenuation parameters under multiple tests should be relatively small and fluctuate within a small range. Therefore, this embodiment normalizes the insulation performance attenuation parameters of the heating cable under each insulation performance test to obtain a normalized value. The standard deviation of the normalized value of the heating cable under all insulation performance tests is calculated. If the standard deviation ε'<0.1, the insulation performance of the heating cable is good; otherwise, the insulation performance of the heating cable is unqualified. Among them, in order to ensure the accuracy of the judgment of the insulation performance of the heating cable, 0.1 is the preset fluctuation threshold. When the standard deviation is less than the fluctuation threshold, it means that the insulation performance attenuation parameters under multiple tests are relatively uniform, and the insulation performance of the heating cable is good.

[0070] The present application obtains characteristic current by using AC superposition detection technology, and then analyzes the monitoring data of the heating cable under different temperature parameters during the heating process, simulates the heating environment of the heating cable during operation, detects the insulation performance parameters of the heating cable, and analyzes the insulation performance state parameters of the heating cable based on the obtained parameters, and obtains the changes in the insulation performance state parameters through multiple tests, so as to judge the insulation performance of the heating cable, and then obtain the real insulation performance evaluation result of the heating cable, thereby improving the test effect and accuracy of the insulation performance of the heating cable.

[0071] Based on the same inventive concept as the above method, an embodiment of the present application also provides a heating cable insulation performance testing system, including a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the steps of any one of the above-mentioned heating cable insulation performance testing methods are implemented.

[0072] Through the above description of the implementation method in combination with the accompanying drawings, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0073] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A method for testing the insulation performance of a heating cable, characterized in that: The method comprises the following steps: S1, real-time acquisition of characteristic current, insulation layer temperature and insulation resistance value of the heating cable during each insulation performance test; S2, obtaining the temperature rise rate change value at each moment according to the temperature change of the insulation layer between adjacent moments; dividing the temperature rise stage according to the numerical distribution of the temperature rise rate change values ​​at consecutive moments; S3, according to the comparison of the insulation resistance values ​​at the beginning and the end of each temperature rise stage, the insulation coefficient of the heating cable in each temperature rise stage is obtained; according to the insulation coefficient of the heating cable in each temperature rise stage, the temperature rise rate change value at all times and the time length of the temperature rise stage, the insulation change parameter of each temperature rise stage is obtained; S4, according to the numerical distribution of characteristic current in each temperature rise stage, the current change degree value in each temperature rise stage is obtained; according to the time length, current change degree value and insulation change parameter of all temperature rise stages, the insulation performance attenuation parameter of the heating cable is obtained; S5, obtaining the insulation performance test result of the heating cable according to the concentration degree of the numerical distribution of the insulation performance attenuation parameter of the heating cable under all insulation performance tests.

2. A method for testing the insulation performance of a heating cable according to claim 1, characterized in that: The step of obtaining the temperature rise rate change value at each moment according to the temperature change of the insulation layer between adjacent moments includes: The temperature change rate at each moment is obtained according to the temperature difference of the insulation layer between adjacent moments; the difference between the temperature change rate at each moment and the next moment is used as the temperature rise rate change value at each moment.

3. A method for testing the insulation performance of a heating cable as claimed in claim 2, characterized in that: The method of obtaining the temperature change rate at each moment according to the temperature difference between adjacent moments includes: recording the temperature change rate at the i-th moment as v i , Where t is the time interval between adjacent moments; w i+1 、w i are the insulation layer temperatures at the i+1th and ith moments respectively.

4. A method for testing the insulation performance of a heating cable according to claim 1, characterized in that: The temperature rise stages are divided according to the numerical distribution of the temperature rise rate change values ​​at consecutive moments, including: A time period consisting of consecutive moments in which the normalized value of the temperature rise rate change value is less than a preset threshold is recorded as a temperature rise stage.

5. A method for testing the insulation performance of a heating cable according to claim 1, characterized in that: The method for obtaining the insulation coefficient of the heating cable at each temperature rise stage includes: The ratio of the insulation resistance value at the last moment of the temperature rise stage to the insulation resistance value at the first moment of the temperature rise stage is calculated, and the normalized value of the ratio is used as the insulation coefficient of the heating cable in the temperature rise stage.

6. A method for testing insulation performance of a heating cable according to claim 1, characterized in that: The method for obtaining the insulation change parameters at each temperature rise stage includes: Among them, g a is the insulation change parameter in the ath temperature rise stage; δ a is the insulation change parameter in the ath temperature rise stage; Δt a is the time length of the ath temperature rise stage; the time length is the time difference between the first and last moments of the temperature rise stage; v y ' is the change value of the temperature rise rate at the yth moment in the ath temperature rise stage; n is the number of moments included in the ath temperature rise stage.

7. A method for testing insulation performance of a heating cable according to claim 1, characterized in that: The method for calculating the current change degree value in each temperature rise stage includes: The maximum value of the characteristic current at all times during the detection process is obtained; the maximum mean value of the characteristic current at all times in the temperature rise stage is calculated; and the difference between the maximum value and the maximum mean value is used as the current change degree value in the temperature rise stage.

8. A method for testing insulation performance of a heating cable according to claim 1, characterized in that: The method for obtaining the insulation performance attenuation parameter of the heating cable specifically includes: Among them, R is the insulation performance attenuation parameter of the heating cable, m is the number of temperature rise stages, τ a is the current change value in the ath temperature rise stage, Δt a is the duration of the ath temperature rise stage, g a is the insulation change parameter in the temperature rise stage, and softsign() uses the derivative function of the softsign function to normalize the result.

9. A method for testing insulation performance of a heating cable according to claim 1, characterized in that: The method of obtaining the insulation performance test result of the heating cable according to the concentration degree of the numerical distribution of the insulation performance attenuation parameter of the heating cable under all insulation performance tests includes: The insulation performance attenuation parameters of the heating cable under each insulation performance test are normalized to obtain a normalized value; the standard deviation of the normalized value of the heating cable under all insulation performance tests is calculated; if the standard deviation is less than a preset fluctuation threshold, the insulation performance of the heating cable is good; otherwise, the insulation performance of the heating cable is unqualified.

10. A heating cable insulation performance testing system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of a method for testing the insulation performance of a heating cable as described in any one of claims 1 to 9 are implemented.

Images