Polypropylene cable insulation performance evaluation method, device, equipment and medium

Abstract

This application relates to a method, apparatus, computer equipment, computer-readable storage medium, and computer program product for evaluating the insulation performance of polypropylene cables. The method includes: obtaining multi-layer slices of the insulation layer portion of the polypropylene cable to be evaluated; the polypropylene cable includes a conductor layer and an insulation layer; each slice corresponds to an insulation layer portion of the polypropylene cable at a different distance from the conductor layer; performing dielectric performance tests on each slice to obtain the corresponding dielectric parameters; simulating each slice using a simulation tool to obtain the working state parameters of the insulation material at different positions in the radial direction within each slice; obtaining the insulation performance evaluation result corresponding to each slice based on the dielectric parameters corresponding to each slice, and / or the working state parameters of the insulation material at different positions in the radial direction within each slice, and further obtaining the insulation performance evaluation result of the insulation layer of the polypropylene cable to be evaluated. This method can improve the efficiency of cable insulation performance evaluation.

Description

Technical Field

[0001] This application relates to the field of cable testing technology, and in particular to a method, apparatus, computer equipment, computer-readable storage medium, and computer program product for evaluating the insulation performance of polypropylene cables. Background Technology

[0002] During the use of cables, the internal insulation material undergoes a series of changes due to the long-term applied electrothermal stress. Therefore, it is necessary to study the aging characteristics of cable insulation material under long-term working conditions.

[0003] Traditional techniques involve hot pressing, where raw granules identical to the cable insulation material are hot-pressed to create samples. Insulation performance parameters are then evaluated after aging tests. However, the aged samples differ from the original cable, leading to inaccurate data analysis. Another approach is to directly measure the cable itself, but this requires a separate, large, and complex cable measurement system. Using these traditional techniques to measure the performance parameters of polypropylene cables is neither efficient nor accurate in obtaining insulation performance evaluation results. Summary of the Invention

[0004] Therefore, it is necessary to provide a method, apparatus, computer equipment, computer-readable storage medium, and computer program product that can efficiently and accurately obtain the evaluation results of the insulation performance of polypropylene cables, addressing the aforementioned technical problems.

[0005] In a first aspect, this application provides a method for evaluating the insulation performance of polypropylene cables, including:

[0006] Obtain multi-layer slices of the insulation layer portion of the polypropylene cable to be evaluated; the polypropylene cable includes a conductor layer and an insulation layer; each slice corresponds to an insulation layer portion of the polypropylene cable at a different distance from the conductor layer;

[0007] Dielectric property tests were performed on each of the slices to obtain the dielectric parameters corresponding to each slice.

[0008] The working state parameters of the insulating material at different positions in the radial direction of each slice are obtained by simulating each slice using simulation tools.

[0009] Based on the dielectric parameters corresponding to each slice and / or the working state parameters of the insulating material at different positions in the radial direction of each slice, the insulation performance evaluation results corresponding to each slice are obtained.

[0010] Based on the insulation performance evaluation results corresponding to each slice, the insulation performance evaluation results of the insulation layer of the polypropylene cable to be evaluated are obtained.

[0011] In one embodiment, the operating state parameters include the electric field intensity distribution at different locations in the radial direction of each slice; the dielectric parameters include the cumulative insulation failure loss value and insulation withstand index corresponding to each slice;

[0012] The step of obtaining the insulation performance evaluation result for each slice based on the dielectric parameters corresponding to each slice and / or the working state parameters of the insulating material at different positions in the radial direction of each slice includes:

[0013] Based on the cumulative insulation failure loss value and insulation tolerance index corresponding to each slice, as well as the electric field intensity distribution at different positions in the radial direction of each slice, the remaining insulation service time corresponding to each slice is obtained.

[0014] The remaining insulation service time corresponding to each slice is compared with the preset insulation service time to obtain the insulation performance evaluation results corresponding to each slice for electric field strength.

[0015] In one embodiment, the operating state parameters also include the operating temperature distribution at different locations in the radial direction of each slice;

[0016] The step of obtaining the insulation performance evaluation result for each slice based on the dielectric parameters corresponding to each slice and / or the working state parameters of the insulating material at different positions in the radial direction of each slice includes:

[0017] Based on the working temperature distribution at different positions in the radial direction of each slice, the reaction activation energy of polypropylene, and the gas constant, the insulation thermal aging time corresponding to each slice is obtained.

[0018] The insulation thermal aging time of each slice is compared with the preset insulation service time to obtain the insulation performance evaluation results corresponding to each slice at the working temperature.

[0019] In one embodiment, the dielectric parameters include the cumulative loss value of insulation failure and the insulation tolerance index corresponding to each slice;

[0020] The step of performing dielectric property testing on each of the slices to obtain the dielectric parameters corresponding to each slice includes:

[0021] A step voltage test was performed on each of the slices to obtain the cumulative insulation failure loss value and insulation tolerance index corresponding to each slice.

[0022] In one embodiment, the operating state parameters include the electric field intensity distribution at different locations in the radial direction of each slice and the operating temperature distribution at different locations in the radial direction.

[0023] The step of simulating each slice using simulation tools to obtain the working state parameters of the insulating material at each location in each slice includes:

[0024] The preset operating current, preset operating voltage, thickness parameters of each slice, and insulation layer parameters of the polypropylene cable to be evaluated are input into the simulation tool. Through simulation analysis, the electric field intensity distribution and operating temperature distribution at different positions in the radial direction of each slice are obtained. The insulation layer parameters are related to the thermal conductivity of polypropylene.

[0025] In one embodiment, obtaining a multilayer slice of the insulation layer portion of the polypropylene cable to be evaluated includes:

[0026] Using a ring slicing device, the polypropylene cable to be evaluated is divided into multiple sub-insulation layers with different distances from the conductor layer according to the thickness of the insulation layer, resulting in multi-layer slices corresponding to the sub-insulation layers; each slice is located in the same cross-section of the polypropylene cable to be evaluated.

[0027] In one embodiment, the method further comprises:

[0028] Space charge testing and isothermal relaxation testing are performed on each slice to obtain the distribution state of the internal traps in the dielectric corresponding to each slice. Based on the distribution state of the internal traps in the dielectric, distribution density analysis and distribution depth analysis are performed to obtain the insulation evaluation results of each slice.

[0029] Secondly, this application also provides a polypropylene cable insulation performance evaluation device, comprising:

[0030] The slice acquisition module is used to acquire multi-layer slices of the insulation layer portion of the polypropylene cable to be evaluated; the polypropylene cable includes a conductor layer and an insulation layer; each slice corresponds to an insulation layer portion of the polypropylene cable at a different distance from the conductor layer;

[0031] The dielectric parameter acquisition module is used to perform dielectric performance testing on each of the slices and obtain the dielectric parameters corresponding to each slice.

[0032] The working state parameter acquisition module is used to simulate each of the slices using simulation tools to obtain the working state parameters of the insulating material at different positions in the radial direction of each slice;

[0033] The insulation performance evaluation module is used to obtain the insulation performance evaluation result of each slice based on the dielectric parameters corresponding to each slice and / or the working state parameters of the insulation material at different positions in the radial direction of each slice; it is also used to obtain the insulation performance evaluation result of the insulation layer of the polypropylene cable to be evaluated based on the insulation performance evaluation result of each slice.

[0034] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described in the first aspect.

[0035] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0036] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method described in the first aspect.

[0037] The aforementioned methods, apparatus, computer equipment, computer-readable storage media, and computer program products for evaluating the insulation performance of polypropylene cables, through multi-layer slice analysis, can more accurately reflect the insulation performance of the insulation layer at different locations, improving the comprehensiveness of the insulation performance evaluation. Combined with dielectric performance testing and simulation tools, insulation performance can be evaluated from different perspectives. Specifically, the dielectric properties of each slice are tested, and the measured dielectric parameters reflect the actual performance of the material. Furthermore, simulations are used to model the operating parameters of each slice under actual working conditions. By combining the dielectric parameters and operating state parameters, a more comprehensive insulation performance evaluation of the insulation layer can be performed, improving the reliability of the insulation performance evaluation results. Potential insulation failures can be identified in advance, enhancing the safety of cable use. In addition, by testing and evaluating cable slices, the workload of evaluating the entire cable is reduced, improving evaluation efficiency. Attached Figure Description

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 This is a flowchart illustrating a method for evaluating the insulation performance of a polypropylene cable in one embodiment.

[0040] Figure 2 This is a schematic diagram of the process for obtaining insulation performance evaluation results based on dielectric parameters and operating state parameters in one embodiment;

[0041] Figure 3 This is a flowchart illustrating the process of obtaining insulation performance evaluation results based on dielectric parameters and operating state parameters in another embodiment.

[0042] Figure 4 This is a flowchart illustrating a method for evaluating the insulation performance of polypropylene cables in a specific embodiment.

[0043] Figure 5 This is a schematic diagram of the structure of a multilayer slice in a polypropylene cable to be evaluated in a specific embodiment;

[0044] Figure 6 This is a flowchart illustrating the data processing flow in a polypropylene cable insulation performance evaluation method according to a specific embodiment.

[0045] Figure 7 This is a schematic diagram showing the electric field intensity distribution of the cable insulation layer at different locations in a specific embodiment.

[0046] Figure 8 This is a schematic diagram showing the operating temperature distribution of the cable insulation layer at different locations in a specific embodiment.

[0047] Figure 9 This is a schematic diagram of the space charge measurement system in a specific embodiment;

[0048] Figure 10 This is a schematic diagram of the internal trap distribution measurement system in a specific embodiment;

[0049] Figure 11 This is a structural block diagram of a polypropylene cable insulation performance evaluation device in one embodiment;

[0050] Figure 12 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0052] In one embodiment, such as Figure 1As shown, a method for evaluating the insulation performance of polypropylene cables is provided. This embodiment illustrates the application of this method to a server. It is understood that this method can also be applied to a terminal, and further to a system including both a terminal and a server, and implemented through interaction between the terminal and the server. In this embodiment, the method includes the following steps:

[0053] Step S202: Obtain multi-layer slices of the insulation layer portion of the polypropylene cable to be evaluated.

[0054] The polypropylene cable includes a conductor layer and an insulation layer; each slice corresponds to an insulation layer portion of the polypropylene cable that is at a different distance from the conductor layer.

[0055] For example, the server can obtain multi-layer slices of the insulation layer of the polypropylene cable to be evaluated through a cutting device, such as inner layer slices, middle layer slices, outer layer slices, etc.

[0056] Step S204: Perform dielectric property testing on each slice to obtain the dielectric parameters corresponding to each slice.

[0057] Among them, dielectric parameters can be indicators used to evaluate the performance of insulating materials, such as dielectric constant, dielectric loss factor and breakdown voltage.

[0058] For example, the server performs dielectric performance tests on each slice to obtain the dielectric parameters corresponding to each slice.

[0059] Step S206: Simulate each slice using a simulation tool to obtain the working state parameters of the insulating material at different positions in the radial direction of each slice.

[0060] Among them, the working state parameters can be parameters used to characterize the working state of the insulating material in the actual operating environment. Because the distance between the insulating material and the conductor layer at different positions in the radial direction of the insulating layer is different, the influence of the conductor layer during operation is also different. Therefore, it is necessary to obtain the working state parameters of the insulating material at different positions in the radial direction in each slice to fully characterize the working state of the insulating material in the actual operating environment.

[0061] For example, a simulation tool can be deployed in the server. The server uses the simulation tool to simulate each slice and obtain the working state parameters of the insulating material at different positions in the radial direction of each slice.

[0062] Step S208: Based on the dielectric parameters corresponding to each slice and / or the working state parameters of the insulating material at different positions in the radial direction of each slice, the insulation performance evaluation results corresponding to each slice are obtained.

[0063] The insulation performance evaluation results for each slice can be obtained by the server based on the dielectric parameters of each slice; or by the server based on the working state parameters of the insulating material at different positions in the radial direction of each slice; or by the server based on the dielectric parameters of each slice and the working state parameters of the insulating material at different positions in the radial direction of each slice.

[0064] Step S210: Based on the insulation performance evaluation results corresponding to each slice, obtain the insulation performance evaluation results of the insulation layer of the polypropylene cable to be evaluated.

[0065] The server can obtain the overall insulation performance evaluation result of the polypropylene cable insulation layer based on the insulation performance evaluation results of slices at different locations. For example, if the insulation performance evaluation results of slices at different locations all indicate good insulation performance and the remaining insulation life exceeds the design life, then the insulation performance evaluation result of the polypropylene cable insulation layer can be that the overall condition of the polypropylene cable insulation layer is good and meets the requirements for safe operation.

[0066] In the aforementioned method for evaluating the insulation performance of polypropylene cables, multi-layer slicing analysis can more accurately reflect the insulation performance of the insulation layer at different locations, improving the comprehensiveness of the insulation performance evaluation. Combined with dielectric performance testing and simulation tools, insulation performance can be evaluated from different perspectives. Specifically, the dielectric properties of each slice are tested, and the measured dielectric parameters reflect the actual performance of the material. Furthermore, simulations are used to model the operating parameters of each slice under actual working conditions. Combining the dielectric parameters and operating state parameters allows for a more comprehensive evaluation of the insulation performance, improving the reliability of the evaluation results and enabling early identification of potential insulation failures, thus enhancing cable safety. Additionally, testing and evaluating cable slices reduces the workload of evaluating the entire cable, improving evaluation efficiency.

[0067] In an exemplary embodiment, the operating state parameters include the electric field intensity distribution at different locations in the radial direction within each slice; the dielectric parameters include the cumulative insulation failure loss value and insulation withstand index corresponding to each slice; such as Figure 2 As shown, step S208 may include the following steps:

[0068] Step S302: Based on the cumulative insulation failure loss value, insulation tolerance index, and electric field intensity distribution at different locations in the radial direction of each slice, the remaining insulation service time of each slice is obtained.

[0069] The cumulative insulation failure loss value refers to the total loss of the cable insulation material in the slices during use due to factors such as electric fields, leading to insulation failure under preset conditions. The insulation withstand index, obtained through voltage testing, reflects the insulation material's ability to withstand voltage. A higher index indicates better stability of the insulation material under high voltage and a relatively longer remaining service life. The electric field intensity distribution at different radial locations within each slice refers to the electric field intensity measured at different radial locations on the cable (e.g., center, 1 / 4 radius, 1 / 2 radius, etc.). Higher electric field intensity may lead to greater insulation loss, thus affecting the remaining insulation service life. The remaining insulation service life refers to the remaining service life of the insulation layer in the slices.

[0070] For example, the server obtains the remaining insulation service time for each slice based on the cumulative insulation failure loss value, insulation withstand index, and electric field intensity distribution at different locations in the radial direction of each slice. Specifically, the remaining insulation service time can be obtained by the following formula:

[0071]

[0072] in, It could refer to the cumulative loss value of insulation failure corresponding to the slice. This could refer to the remaining service life of the insulation corresponding to the slice. This can refer to the distribution of electric field intensity at different locations along the radial direction within a slice. This could refer to the insulation withstand index corresponding to the slice. The remaining service life of the insulation can be calculated using the above formula. .

[0073] Step S304: Compare the remaining insulation service time corresponding to each slice with the preset insulation service time to obtain the insulation performance evaluation results corresponding to each slice for electric field strength.

[0074] For example, the remaining insulation service time corresponding to each slice is compared with the preset insulation service time. If the remaining insulation service time corresponding to the slice is greater than the preset insulation service time, the insulation performance evaluation result corresponding to the slice for the electric field strength can be concluded that the insulation requirements are met.

[0075] In this embodiment, by analyzing and calculating the cumulative insulation failure loss value, insulation tolerance index, and electric field intensity distribution at different locations in the radial direction of each slice, the remaining insulation service time is obtained and compared with the preset insulation service time. This allows for an accurate assessment of the insulation performance of each slice and the acquisition of the actual performance of the insulation material under different electric field intensities, thereby improving the accuracy of the insulation performance assessment of the slice.

[0076] In one exemplary embodiment, the operating status parameters also include the operating temperature distribution at different locations in the radial direction within each slice; such as Figure 3 As shown, step S208 may further include the following steps:

[0077] Step S402: Based on the working temperature distribution at different positions in the radial direction of each slice, the reaction activation energy of polypropylene, and the gas constant, the insulation thermal aging time corresponding to each slice is obtained.

[0078] The operating temperature distribution refers to the specific temperature distribution at different locations along the radius of the slice under operating conditions. The activation energy of the reaction in polypropylene refers to the energy required for the polypropylene material in the slice to become activated during thermal aging, leading to material degradation or a decrease in material properties. Increased temperature causes more molecules in the polypropylene material to gain enough energy to overcome the activation energy barrier, accelerating the aging process. The gas constant is a physical constant, commonly used in the ideal gas law, and frequently used in thermodynamics and chemical reactions to calculate temperature-related reaction rates and thermal aging processes. The insulation thermal aging time refers to the time required for polypropylene insulation material to undergo the thermal aging process at a specific operating temperature.

[0079] For example, the server can calculate the insulation thermal aging time for each slice based on the operating temperature distribution at different locations in the radial direction of each slice, the activation energy of the reaction of polypropylene, and the gas constant, using a formula as follows:

[0080]

[0081] in, It can indicate the thermal aging time of insulation. This can be the activation energy of the reaction corresponding to polypropylene insulation material. It can be the gas constant. It can refer to the set operating temperature. This could refer to the frequency factor. The set operating temperature T is obtained by distributing the operating temperature at different locations along the radial direction in each slice. Then, the operating temperature T, the activation energy E, the gas constant R, and the frequency factor A are substituted into the above formula to calculate the insulation thermal aging time L.

[0082] Step S404: Compare the insulation thermal aging time of each slice with the preset insulation service time to obtain the insulation performance evaluation results corresponding to each slice at the working temperature.

[0083] For example, the server compares the insulation thermal aging time of each slice with the preset insulation service time. If the insulation thermal aging time of one slice is greater than the preset insulation service time, the insulation performance evaluation result for that slice at the working temperature is that it meets the insulation requirements. If the insulation thermal aging time of another slice is less than or equal to the preset insulation service time, it means that the normal insulation effective time of that slice at the working temperature does not meet the preset insulation service time, and the insulation performance evaluation result for that slice is that it does not meet the insulation requirements.

[0084] In this embodiment, by calculating the insulation thermal aging time of each slice, the durability and stability of the polypropylene insulation material in the polypropylene cable at a specific operating temperature can be evaluated more accurately. By understanding the temperature distribution and corresponding thermal aging characteristics at different locations, guidance can be provided for the improvement and optimization of polypropylene insulation materials, thereby enhancing the overall performance of the polypropylene cable.

[0085] In an exemplary embodiment, the dielectric parameters include the cumulative insulation failure loss value and insulation withstand index corresponding to each slice; step S204 may include the following steps: performing a step voltage test on each slice to obtain the cumulative insulation failure loss value and insulation withstand index corresponding to each slice.

[0086] Among them, step voltage test can refer to gradually increasing the voltage applied to the slice during the test in order to obtain the performance of the slice's insulation state as the voltage changes.

[0087] For example, the server performs a step voltage test on each slice. It can apply a gradually increasing voltage to the slice by controlling a test device that can gradually adjust the voltage until the insulation material of the slice shows insulation failure or the applied voltage reaches a preset threshold. Then, by recording the loss at each voltage step, the server evaluates the loss suffered by the insulation material of the slice as the voltage increases, and obtains the cumulative insulation failure loss value and insulation tolerance index corresponding to each slice.

[0088] In this embodiment, the insulation material corresponding to the polypropylene cable slices is tested by step voltage test, which can quantify the cumulative loss of insulation failure and the insulation tolerance index, thereby improving the reliability and safety of the obtained parameters in application.

[0089] In an exemplary embodiment, the operating state parameters include the electric field intensity distribution at different locations in the radial direction of each slice and the operating temperature distribution at different locations in the radial direction; step S206 may include the following steps: inputting the preset operating current, preset operating voltage, thickness parameters of each slice, and insulation layer parameters of the polypropylene cable to be evaluated into the simulation tool, and obtaining the electric field intensity distribution at different locations in the radial direction and the operating temperature distribution at different locations in the radial direction of each slice through simulation analysis; the insulation layer parameters are related to the thermal conductivity of polypropylene.

[0090] In this embodiment, the server can input the preset operating current, preset operating voltage, thickness parameters of each slice, and insulation layer parameters of the polypropylene cable to be evaluated into the simulation tool. The simulation tool constructs a simulation model for the polypropylene cable slice to be evaluated based on the thickness parameters of each slice and the insulation layer parameters. Then, the simulation running conditions are configured according to the preset operating current and preset operating voltage. After the simulation model is configured, simulation analysis is performed. The operating temperature distribution at different positions in the radial direction is obtained through the heat transfer equation. The electric field intensity distribution at different positions in the radial direction is obtained by solving the electric field equation.

[0091] In an exemplary embodiment, step S202 may include the following steps: using a ring slicing device, the polypropylene cable to be evaluated is divided into multiple sub-insulation layers with different distances from the conductor layer according to the thickness of the insulation layer, to obtain multi-layer slices corresponding to the sub-insulation layers; each slice is located in the same cross-section of the polypropylene cable to be evaluated.

[0092] In this embodiment, the annular slicing device refers to a specialized tool for cutting cables, capable of precisely controlling the cutting depth and angle to ensure the cable is uniformly divided into multiple layers. Based on a set insulation layer thickness, the annular slicing device can cut the cable insulation layer into multiple sub-insulation layers. The thickness of each sub-insulation layer and its distance from the conductor layer can be specified according to actual needs. By slicing the same cross-section of the polypropylene cable to be evaluated, it can be ensured that all evaluated slices are taken from a single cross-section of the cable, guaranteeing the continuity, consistency, and comparability of the data evaluation.

[0093] In an exemplary embodiment, the method further includes: performing space charge testing and isothermal relaxation testing on each slice to obtain the dielectric internal trap distribution state corresponding to each slice; performing distribution density analysis and distribution depth analysis based on the dielectric internal trap distribution state to obtain the insulation evaluation result of each slice.

[0094] In this embodiment, space charge testing on the slice can detect and quantify the space charge distribution inside the dielectric. Isothermal relaxation testing on the slice can reveal the dielectric polarization changes at a constant temperature and the influence of internal traps on charge transport. Based on the data from the space charge and isothermal relaxation tests, the distribution of internal traps in the dielectric within the slice is analyzed. A model can be used to calculate the internal trap distribution of different slices, determining the trap content, state, and impact on charge transport. Then, the distribution state of the internal traps is determined based on their distribution, namely, the internal trap density and depth. The internal trap density and depth are then analyzed separately. If the trap density and depth exceed thresholds, it indicates that space charge easily accumulates inside the dielectric (the insulation layer of the slice). This accumulation of space charge easily leads to insulation failure. Therefore, the insulation assessment result for this slice indicates that it is prone to charge accumulation in the insulation layer of the polypropylene cable being evaluated, easily causing insulation failure, requiring close attention from relevant personnel.

[0095] In a specific embodiment, Figure 4 As shown in the figure, this diagram illustrates the basic process of the polypropylene cable insulation performance evaluation method in this embodiment. First, the research object is selected, namely, the physical AC polypropylene cables in different operating states. This embodiment uses cables without type testing and cables after type testing as examples for illustration. Several cable slices are obtained using a loop cable slicer, such as... Figure 5 As shown, based on their distance from the conductor, the samples are divided into inner layer samples, middle layer samples, and outer layer samples (corresponding to multi-layer slices of the insulation layer of the polypropylene cable to be evaluated). Dielectric performance tests are then performed on different cable slices to obtain measurement parameters, yielding dielectric performance parameters for the cable slices (inner layer samples, middle layer samples, and outer layer samples) at different locations. Simulation results are used to obtain the actual operating conditions, i.e., the specific working environment, of the cable insulation material at different locations. Combined with the dielectric performance parameters obtained from the above measurements, the performance changes of the cable slices at different locations are obtained, the overall performance state of the cable at the cable slices is analyzed, and the overall state of the cable insulation material is evaluated.

[0096] Figure 6This embodiment demonstrates the basic data processing flow. Simulation software is used to calculate the operating state of the cable insulation material at different locations (inner layer sample, middle layer sample, outer layer sample), i.e., the simulated insulation operating state at the location, including information such as the electric field strength, operating temperature, and external pressure at that location. Dielectric performance tests on the cable slices, such as breakdown tests, conductivity tests, and space charge tests, are conducted to obtain the basic dielectric parameters of the cable slices at different locations, including breakdown field strength, conductivity current, trap distribution, and space charge accumulation. Combining the cable slice parameters and simulation results, key state assessment parameters such as the operating state and remaining life of the cable slice at that location are obtained, i.e., state assessment and remaining life assessment parameters under the current environment. By integrating the state assessment parameters obtained from cable slices at different locations, the overall operating state of the cable at the slice location (comprehensive cable state assessment and remaining life at the slice location) can be obtained.

[0097] Among these factors, the operating environment of cable insulation materials at different locations is one of the important bases for evaluating the performance parameters of the corresponding insulation materials. The actual operating environment of cables varies at different locations, and the requirements for insulation materials also differ slightly. Figure 7 The figure shows the calculated electric field strength of the cable insulation layer at different locations (the electric field strength distribution at different locations in the radial direction of the slice). Figure 8 This represents the temperature of the cable insulation layer at different locations (the operating temperature distribution at different locations in the radial direction within the slice). Combined with... Figure 7 as well as Figure 8 It can be seen that the portion of the insulating material closest to the conductor layer experiences the strongest electric field and the highest temperature, resulting in a more severe aging process and poorer performance. Under long-term electrical stress, the lifespan of the insulating material can be expressed by the following formula:

[0098]

[0099] In the formula, The cumulative loss that causes insulation failure; Indicates insulation life; The operating electric field strength (obtained from the above simulation calculations); This represents the insulation withstand index. Except for the electric field strength, which is obtained through simulation calculations, all other data can be obtained through step voltage tests. The corresponding remaining lifetime can be calculated using the above formula. If its lifespan exceeds the design lifespan If the insulation is satisfactory, it can be considered that the insulation basically meets the insulation requirements. It should also be noted that this embodiment proposes analyzing and measuring three layers of samples: the inner layer, the middle layer, and the outer layer. Only if all three layers meet the requirements can it be concluded that the insulation material at that location of the cable basically meets the requirements.

[0100] In addition to considering the effects of electrical stress, the evaluation of insulation materials must also take into account the effects of thermal stress. Under prolonged exposure to high temperatures, insulation materials can also undergo chemical reactions, leading to degradation. The degradation of insulation materials under thermal conditions can be described by the Arrhenius equation:

[0101]

[0102] Where, Represents the thermal aging life of insulation. This represents the activation energy for the reaction of polypropylene. The gas constant is... This represents the aging temperature (operating temperature). The insulation life of the insulating material can be calculated using the above formula. If the insulation life exceeds the design life, the insulating material can be considered to basically meet the requirements.

[0103] In addition to basic lifetime assessment, other factors affect the dielectric properties of insulating materials, such as the distribution of traps within the dielectric. Therefore, this embodiment will also perform space charge measurement and isothermal relaxation testing on cable slices to further evaluate the dielectric insulation condition. Figure 9 This is a structural diagram of a space charge measurement system. The voltage across the sample (slice) is controlled by an isolation capacitor, a pulse power supply, and a programmable DC power supply. The accumulation of charge is measured by a piezoelectric sensor, an amplifier, an oscilloscope, and a calculator, because changes in voltage can reflect the accumulation of charge in the sample (slice). Figure 10 To measure the internal trap distribution, a system structure diagram is provided. A programmable DC power supply controls the voltage across a slice located between the high-voltage electrode and the measuring electrode. A protective electrode is installed on the slice to ensure safe operation during the measurement process. A pA ammeter is used to measure a minute current, and the trap state and distribution within the dielectric can be inferred from this measured current. Space charge testing using a space charge measurement system can reflect the internal trap distribution of the dielectric through charge accumulation. Isothermal relaxation current is used to qualitatively study the internal distribution of the dielectric by analyzing depolarization current. In the aging theory of solid dielectrics, the dielectric can be equivalent to three pairs of parallel resistors and capacitors, representing three polarization processes within the dielectric: solid insulator polarization, amorphous-crystalline interface polarization, and various defects introduced by aging, such as the polarization of metal salts and hydrated ions. Based on this theory, the isothermal relaxation current of the dielectric can be fitted using a three-exponential function.

[0104]

[0105] in, Used to characterize the self-polarization of insulating dielectrics; Used to characterize the presence of amorphous and crystalline polarization in dielectrics; Used to characterize the polarization of metal salts, hydrated ions, and various defects caused by aging. In summary, It is related to the properties of the insulating material itself. It is related to the degree of insulation degradation.

[0106] According to Simmons' isothermal relaxation theory, the depolarization current and trap energy level The trap density has the following relationship:

[0107]

[0108]

[0109] In the formula, This is the bottom energy level of the conduction band; For trap energy levels; Boltzmann's constant; For temperature; Escape frequency; The initial electron occupies the energy level; This is the trap energy level. Therefore, it can be achieved through... The diagram provides a clear and intuitive analysis of the distribution of traps within the dielectric material.

[0110] The above analysis reveals the distribution of traps within the dielectric. Extremely high trap density and depth indicate a high likelihood of space charge accumulation within the dielectric. This accumulation of space charge can easily lead to insulation failure. Therefore, engineers must pay close attention to cables in this location.

[0111] In summary, this embodiment combines the advantages and disadvantages of the hot-pressing method and the overall cable measurement method, and proposes a method for evaluating the condition parameters of AC polypropylene cables based on cable slices. This method uses cable slices as the research object, making the research results relevant to practical engineering applications. Furthermore, slice-based research is simpler than cable body testing. This embodiment is based on evaluating the remaining life of the insulation material, and further incorporates trap energy level distribution calculations, considering a broad range of factors, thus giving the evaluation results a certain degree of practicality. Therefore, this embodiment possesses both practicality and innovation.

[0112] Traditional techniques utilize the hot-pressing method for evaluating the condition of cable insulation materials. This method involves aging sheet-like samples, formed from granules, under different conditions and comparing them with untreated samples to determine the degradation patterns of dielectric properties under different aging states. This method is simple, fast, and effective because most tests can be performed using existing measuring equipment, and measurements on sheet-like samples are straightforward and efficient. However, its drawback lies in the fact that sheet-like samples actually differ somewhat from cable insulation materials, making it difficult to perfectly correlate the results with the actual operating conditions of cables, thus limiting its practical value in engineering applications. Specifically, the hot-pressing process is susceptible to environmental influences, and different cooling temperatures significantly affect sample crystallization. Even samples prepared in the same batch may exhibit slight differences in performance due to objective limitations. This is reflected in the fact that even within the same batch of samples, different insulation properties exist, making it difficult to separate sample preparation factors from aging factors during aging tests, leading to inaccurate data analysis. Furthermore, samples prepared by hot pressing differ in performance from the insulation materials of operating power cables. Actual cable operation is influenced by multiple factors, including not only electrothermal factors but also pressure, air, and humidity. In addition, the extrusion process also causes a series of effects on the insulation material. Therefore, hot pressing cannot accurately correlate hot-pressed samples with actual operating insulation materials. While studying the basic insulation properties of hot-pressed samples can yield results, the differences between hot-pressed samples and actual cable insulation materials limit the practical engineering reference value of the research results obtained through hot pressing.

[0113] This method is a comprehensive evaluation method for cable insulation material condition, involving overall testing of cables. It assesses the variation in dielectric properties of cable insulation materials under different operating conditions by measuring the overall dielectric properties of various cables under different operating states. The advantage of this method is that it can fully correspond to the performance parameters of cable insulation materials under different operating states, providing significant reference value for practical engineering. However, its disadvantages include the need for temporary equipment setup for testing the dielectric parameters of the cable itself, the relatively rigid testing method, the large size of the equipment, insufficient measurement flexibility, and the typically high demand for comprehensive testing requiring substantial manpower and resources.

[0114] In summary, the hot-pressing method is relatively simple in sample preparation and measurement, but its drawback is that it cannot directly correlate the aging state of the prepared sample with the condition of the cable in actual operation. The overall cable measurement method can directly reflect the cable's operating state, but it is complex and cumbersome, requiring significant manpower and resources to build the measurement system. Compared to the hot-pressing method, the method proposed in this embodiment has the advantage of obtaining more accurate test parameters that better correspond to the cable's performance parameters during actual operation; compared to cable body measurement, it is simpler in its testing method, requiring only existing equipment for measuring sheet-like samples.

[0115] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0116] Based on the same inventive concept, this application also provides a polypropylene cable insulation performance evaluation device for implementing the polypropylene cable insulation performance evaluation method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the polypropylene cable insulation performance evaluation device provided below can be found in the limitations of the polypropylene cable insulation performance evaluation method described above, and will not be repeated here.

[0117] In one exemplary embodiment, such as Figure 11 As shown, a polypropylene cable insulation performance evaluation device is provided, comprising: a slice acquisition module 901, a dielectric parameter acquisition module 902, a working state parameter acquisition module 903, and an insulation performance evaluation module 904, wherein:

[0118] The slice acquisition module 901 is used to acquire multi-layer slices of the insulation layer portion of the polypropylene cable to be evaluated; the polypropylene cable includes a conductor layer and an insulation layer; each slice corresponds to an insulation layer portion of the polypropylene cable at a different distance from the conductor layer;

[0119] The dielectric parameter acquisition module 902 is used to perform dielectric performance testing on each slice and obtain the dielectric parameters corresponding to each slice.

[0120] The working state parameter acquisition module 903 is used to simulate each slice using simulation tools to obtain the working state parameters of the insulating material at different positions in the radial direction of each slice;

[0121] The insulation performance evaluation module 904 is used to obtain the insulation performance evaluation results of each slice based on the dielectric parameters corresponding to each slice and / or the working state parameters of the insulation material at different positions in the radial direction of each slice; it is also used to obtain the insulation performance evaluation results of the insulation layer of the polypropylene cable to be evaluated based on the insulation performance evaluation results of each slice.

[0122] In an exemplary embodiment, the operating state parameters include the electric field intensity distribution at different positions in the radial direction of each slice; the dielectric parameters include the cumulative insulation failure loss value and insulation tolerance index corresponding to each slice; the insulation performance evaluation module 904 is further configured to obtain the remaining insulation service time corresponding to each slice based on the cumulative insulation failure loss value, insulation tolerance index, and electric field intensity distribution at different positions in the radial direction of each slice; and compare the remaining insulation service time corresponding to each slice with the preset insulation service time to obtain the insulation performance evaluation result corresponding to each slice for the electric field intensity.

[0123] In an exemplary embodiment, the working state parameters also include the working temperature distribution at different positions in the radial direction of each slice; the insulation performance evaluation module 904 is further used to obtain the insulation thermal aging time corresponding to each slice based on the working temperature distribution at different positions in the radial direction of each slice, the reaction activation energy corresponding to polypropylene, and the gas constant; and to compare the insulation thermal aging time of each slice with the preset insulation service time to obtain the insulation performance evaluation result corresponding to each slice for the working temperature.

[0124] In an exemplary embodiment, the dielectric parameters include the cumulative insulation failure loss value and insulation tolerance index corresponding to each slice; the dielectric parameter acquisition module 902 is further used to perform a step voltage test on each slice to obtain the cumulative insulation failure loss value and insulation tolerance index corresponding to each slice.

[0125] In an exemplary embodiment, the operating state parameters include the electric field intensity distribution at different locations in the radial direction of each slice and the operating temperature distribution at different locations in the radial direction.

[0126] In an exemplary embodiment, the above-mentioned working state parameter acquisition module 903 is further used to input the preset working current, preset working voltage, thickness parameters of each slice, and insulation layer parameters of the polypropylene cable to be evaluated into the simulation tool, and obtain the electric field intensity distribution and working temperature distribution at different positions in the radial direction of each slice through simulation analysis; the insulation layer parameters are related to the thermal conductivity of polypropylene.

[0127] In an exemplary embodiment, the slice acquisition module 901 is further configured to use an annular slicing device to divide the polypropylene cable to be evaluated into multiple sub-insulation layers with different distances from the conductor layer according to the thickness of the insulation layer, thereby obtaining multi-layer slices corresponding to the sub-insulation layers; each slice is located in the same cross-section of the polypropylene cable to be evaluated.

[0128] In an exemplary embodiment, the insulation performance evaluation module 904 is further configured to perform space charge testing and isothermal relaxation testing on each slice to obtain the dielectric internal trap distribution state corresponding to each slice, and perform distribution density analysis and distribution depth analysis based on the dielectric internal trap distribution state to obtain the insulation evaluation result of each slice.

[0129] Each module in the aforementioned polypropylene cable insulation performance evaluation device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0130] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 12 As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and databases. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for evaluating the insulation performance of polypropylene cables.

[0131] Those skilled in the art will understand that Figure 12The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0132] In one embodiment, a computer device is further provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0133] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0134] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0135] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0136] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0137] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for evaluating the insulation performance of polypropylene cables, characterized in that, The method includes: Obtain multi-layer slices of the insulation layer portion of the polypropylene cable to be evaluated; the polypropylene cable includes a conductor layer and an insulation layer; each slice corresponds to an insulation layer portion of the polypropylene cable at a different distance from the conductor layer; Dielectric properties are tested on each of the slices to obtain dielectric parameters corresponding to each slice; the dielectric parameters include the cumulative insulation failure loss value and insulation withstand index corresponding to each slice. The working state parameters of the insulating material at different positions in the radial direction of each slice are obtained by simulating each slice using simulation tools; the working state parameters include the electric field intensity distribution at different positions in the radial direction of each slice. Based on the dielectric parameters corresponding to each slice and the working state parameters of the insulating material at different positions in the radial direction of each slice, the insulation performance evaluation results corresponding to each slice are obtained, including: obtaining the remaining insulation service time corresponding to each slice based on the cumulative insulation failure loss value, insulation tolerance index, and electric field intensity distribution at different positions in the radial direction of each slice; comparing the remaining insulation service time corresponding to each slice with the preset insulation service time to obtain the insulation performance evaluation results corresponding to each slice for electric field intensity; Based on the insulation performance evaluation results corresponding to each slice, the insulation performance evaluation results of the insulation layer of the polypropylene cable to be evaluated are obtained.

2. The method according to claim 1, characterized in that, The working status parameters also include the working temperature distribution at different locations in the radial direction of each slice; The process of obtaining insulation performance evaluation results for each slice based on the dielectric parameters corresponding to each slice and the operating state parameters of the insulating material at different positions in the radial direction of each slice includes: Based on the working temperature distribution at different positions in the radial direction of each slice, the reaction activation energy of polypropylene, and the gas constant, the insulation thermal aging time corresponding to each slice is obtained. The insulation thermal aging time of each slice is compared with the preset insulation service time to obtain the insulation performance evaluation results corresponding to each slice at the working temperature.

3. The method according to claim 1, characterized in that, The dielectric parameters include the cumulative insulation failure loss value and insulation tolerance index corresponding to each slice; The step of performing dielectric property testing on each of the slices to obtain the dielectric parameters corresponding to each slice includes: A step voltage test was performed on each of the slices to obtain the cumulative insulation failure loss value and insulation tolerance index corresponding to each slice.

4. The method according to claim 2, characterized in that, The operating state parameters include the electric field intensity distribution at different positions in the radial direction of each slice, as well as the electric field intensity distribution and operating temperature distribution at different positions in the radial direction. The step of simulating each slice using simulation tools to obtain the working state parameters of the insulating material at each location in each slice includes: The preset operating current, preset operating voltage, thickness parameters of each slice, and insulation layer parameters of the polypropylene cable to be evaluated are input into the simulation tool. Through simulation analysis, the electric field intensity distribution and operating temperature distribution at different positions in the radial direction of each slice are obtained. The parameters of the insulating layer are related to the thermal conductivity of polypropylene.

5. The method according to claim 1, wherein The process of obtaining multi-layer slices of the insulation layer portion of the polypropylene cable to be evaluated includes: Using a ring slicing device, the polypropylene cable to be evaluated is divided into multiple sub-insulation layers with different distances from the conductor layer according to the thickness of the insulation layer, resulting in multi-layer slices corresponding to the sub-insulation layers; each slice is located in the same cross-section of the polypropylene cable to be evaluated.

6. The method according to claim 1, characterized in that, The method further includes: Space charge testing and isothermal relaxation testing are performed on each slice to obtain the distribution state of the internal traps in the dielectric corresponding to each slice. Based on the distribution state of the internal traps in the dielectric, distribution density analysis and distribution depth analysis are performed to obtain the insulation evaluation results of each slice.

7. A device for evaluating the insulation performance of polypropylene cables, characterized in that, The device includes: The slice acquisition module is used to acquire multi-layer slices of the insulation layer portion of the polypropylene cable to be evaluated; the polypropylene cable includes a conductor layer and an insulation layer; each slice corresponds to an insulation layer portion of the polypropylene cable at a different distance from the conductor layer; The dielectric parameter acquisition module is used to perform dielectric performance testing on each of the slices to obtain the dielectric parameters corresponding to each slice; the dielectric parameters include the cumulative insulation failure loss value and insulation withstand index corresponding to each slice. The working state parameter acquisition module is used to simulate each of the slices using simulation tools to obtain the working state parameters of the insulating material at different positions in the radial direction of each slice; the working state parameters include the electric field intensity distribution at different positions in the radial direction of each slice; The insulation performance evaluation module is used to obtain the insulation performance evaluation result of each slice based on the dielectric parameters corresponding to each slice and the working state parameters of the insulation material at different positions in the radial direction of each slice; further, it is used to obtain the remaining insulation service time of each slice based on the cumulative insulation failure loss value, insulation tolerance index, and electric field intensity distribution at different positions in the radial direction of each slice; compare the remaining insulation service time of each slice with the preset insulation service time to obtain the insulation performance evaluation result of each slice for electric field intensity; and also, it is used to obtain the insulation performance evaluation result of the insulation layer of the polypropylene cable to be evaluated based on the insulation performance evaluation results of each slice.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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