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

Abstract

The invention relates to a polypropylene cable insulation performance evaluation method and device, computer equipment, a computer readable storage medium and a computer program product. The method comprises the following steps: acquiring a multi-layer slice of an insulating layer part of a to-be-evaluated polypropylene cable; the polypropylene cable comprises a conductor layer and an insulating layer. Each slice respectively corresponds to an insulating layer part with different distances from a conductor layer in the polypropylene cable; performing dielectric property test on each slice to obtain a dielectric parameter corresponding to each slice; simulating each slice through a simulation tool to obtain working state parameters of the insulating material at different positions in the radius direction in each slice; and according to the dielectric parameter corresponding to each slice and / or the working state parameters of the insulating material at different positions in the radius direction in each slice, obtaining an insulating property evaluation result corresponding to each slice, and further obtaining an insulating property evaluation result of the insulating layer of the to-be-evaluated polypropylene cable. By adopting the method, the cable insulation performance evaluation efficiency can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of cable testing, and in particular to a method, device, computer equipment, computer-readable storage medium and computer program product for evaluating the insulation performance of a polypropylene cable. Background Art

[0002] During the use of cables, with the long-term application of electrical and thermal stress, the internal insulation materials of the cables will undergo a series of changes. Therefore, it is necessary to study the aging characteristics of cable insulation materials under long-term working conditions.

[0003] In traditional technology, the original pellets that are the same as the cable insulation material are selected through hot pressing to obtain samples, and then the insulation performance parameters are evaluated after aging test. However, there are differences between the aged samples and the original cables, which makes the data analysis inaccurate. There is also a method of directly measuring the cable body, but a separate cable body measurement system needs to be built, and the system is large and complex. Using the above traditional technologies to measure the performance parameters of polypropylene cables cannot efficiently and accurately obtain the insulation performance evaluation results of polypropylene cables. Summary of the invention

[0004] Based on this, it is necessary to provide a polypropylene cable insulation performance evaluation method, device, computer equipment, computer readable storage medium and computer program product that can efficiently and accurately obtain the polypropylene cable in response to the above technical problems.

[0005] In a first aspect, the present application provides a method for evaluating the insulation performance of a polypropylene cable, comprising:

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

[0007] Performing a dielectric property test on each of the slices to obtain dielectric parameters corresponding to each of the slices;

[0008] Simulating each of the slices by a simulation tool to obtain working state parameters of the insulating material at different positions in the radial direction of each of the slices;

[0009] Obtaining insulation performance evaluation results corresponding to each of the slices according to dielectric parameters corresponding to each of the slices and / or working state parameters of the insulating material at different positions in the radial direction of each of the slices;

[0010] The insulation performance evaluation result of the insulation layer of the polypropylene cable to be evaluated is obtained according to the insulation performance evaluation result corresponding to each of the slices.

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

[0012] The step of obtaining the insulation performance evaluation result corresponding to each of the slices according to the dielectric parameters corresponding to each of the slices and / or the working state parameters of the insulating material at different positions in the radial direction of each of the slices comprises:

[0013] According to the insulation failure cumulative loss value and the insulation tolerance index corresponding to each of the slices and the electric field intensity distribution at different positions in the radial direction of each of the slices, the remaining insulation service time corresponding to each of the slices is obtained;

[0014] The remaining insulation use time corresponding to each of the slices is compared with the preset insulation use time to obtain the insulation performance evaluation result corresponding to each of the slices with respect to the electric field strength.

[0015] In one embodiment, the working state parameter further includes working temperature distribution at different positions in the radial direction of each slice;

[0016] The step of obtaining the insulation performance evaluation result corresponding to each of the slices according to the dielectric parameters corresponding to each of the slices and / or the working state parameters of the insulating material at different positions in the radial direction of each of the slices comprises:

[0017] According to 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, the insulation heat aging time corresponding to each slice is obtained;

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

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

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

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

[0022] In one of the embodiments, the working state parameters include the electric field intensity distribution at different positions in the radial direction in each of the slices and the working temperature distribution of the electric field intensity distribution at different positions in the radial direction;

[0023] The simulating each of the slices by a simulation tool to obtain the working state parameters of the insulating material at each position in each of the slices includes:

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

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

[0026] The polypropylene cable to be evaluated is divided into a plurality of sub-insulating layers having different distances from the conductor layer according to the thickness of the insulating layer by an annular slicing device to obtain multi-layer slices corresponding to the sub-insulating layers; each of the slices is located in the same cross section of the polypropylene cable to be evaluated.

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

[0028] A space charge test and an isothermal relaxation test are performed on each of the slices to obtain a distribution state of traps inside the dielectric corresponding to each of the slices. A distribution density analysis and a distribution depth analysis are performed based on the distribution state of traps inside the dielectric to obtain an insulation evaluation result of each of the slices.

[0029] In a second aspect, the present application also provides a polypropylene cable insulation performance evaluation device, comprising:

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

[0031] A dielectric parameter acquisition module, used to perform a dielectric property test on each of the slices to obtain dielectric parameters corresponding to each of the slices;

[0032] A working state parameter acquisition module, used to simulate each of the slices through a simulation tool to obtain working state parameters of the insulating material at different positions in the radial direction of each of the slices;

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

[0034] In a third aspect, the present application further provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method described in the first aspect when executing the computer program.

[0035] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method described in the first aspect.

[0036] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, which implements the steps of the method described in the first aspect when executed by a processor.

[0037] The above-mentioned polypropylene cable insulation performance evaluation method, device, computer equipment, computer-readable storage medium and computer program product can more accurately reflect the insulation performance of the insulation layer at different positions through multi-layer slice analysis, improve the comprehensiveness of insulation performance evaluation, and then combine dielectric performance testing and simulation tools for simulation, so as to evaluate insulation performance from different angles, that is, the dielectric performance of each slice is tested, and the measured dielectric parameters can reflect the actual performance of the material, and then simulate the working state parameters of each slice under actual working conditions, and then combine the dielectric parameters and working state parameters to more comprehensively evaluate the insulation performance of the insulation layer, thereby improving the reliability of the insulation performance evaluation results, identifying potential insulation failures in advance, and improving the safety of cable use. In addition, by testing and evaluating the slice pairs of the cable, the workload of the entire cable evaluation is reduced, and the evaluation efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. 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 creative work.

[0039] Figure 1 A schematic diagram of a process for evaluating the insulation performance of a polypropylene cable in one embodiment;

[0040] Figure 2 It is a schematic diagram of a process of obtaining an insulation performance evaluation result according to dielectric parameters and working state parameters in one embodiment;

[0041] Figure 3 It is a schematic diagram of a flow chart of obtaining insulation performance evaluation results according to dielectric parameters and working state parameters in another embodiment;

[0042] Figure 4 A schematic diagram of a process for evaluating the insulation performance of a polypropylene cable in a specific embodiment;

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

[0044] Figure 6 A schematic diagram of a data processing flow in a polypropylene cable insulation performance evaluation method in a specific embodiment;

[0045] Figure 7 A schematic diagram of the electric field intensity distribution of the cable insulation layer at different positions in a specific embodiment;

[0046] Figure 8 is a schematic diagram of the operating temperature distribution of the cable insulation layer at different positions in a specific embodiment;

[0047] Fig. 9 is a schematic structural diagram of a space charge measurement system in a specific embodiment;

[0048] Fig.10 It is a structural schematic diagram of an internal trap distribution measurement system in a specific embodiment;

[0049] Fig.11 A structural block diagram of a polypropylene cable insulation performance evaluation device in one embodiment;

[0050] Fig.12 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

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

[0053] Step S202, obtaining a multi-layer slice of the insulation layer portion of the polypropylene cable to be evaluated.

[0054] The polypropylene cable comprises a conductor layer and an insulation layer; each slice corresponds to a portion of the insulation layer in the polypropylene cable having a different distance from the conductor layer.

[0055] For example, the server may 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, and the like.

[0056] Step S204 , performing a dielectric property test on each slice to obtain 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] Exemplarily, the server performs a dielectric property test on each slice to obtain dielectric parameters corresponding to each slice.

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

[0060] The working state parameter may be a parameter used to characterize the working state of the insulating material under the actual operating environment. Since the insulating material at different positions in the radial direction of the insulating layer is at different distances from the conductor layer, 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 under the actual operating environment.

[0061] Exemplarily, a simulation tool may be deployed in the server, and the server simulates each slice through the simulation tool to obtain the working state parameters of the insulating material at different positions in the radial direction of each slice.

[0062] Step S208, obtaining insulation performance evaluation results corresponding to each slice according to 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.

[0063] Among them, the insulation performance evaluation result corresponding to each slice may refer to that obtained by the server based on the dielectric parameters corresponding to each slice; it may also be that obtained by the server based on the working status parameters of the insulating material at different positions in the radial direction of each slice; it may also be that obtained by the server based on the dielectric parameters corresponding to each slice and the working status parameters of the insulating material at different positions in the radial direction of each slice.

[0064] Step S210, obtaining the insulation performance evaluation result of the insulation layer of the polypropylene cable to be evaluated according to the insulation performance evaluation result corresponding to each slice.

[0065] The server can obtain the overall insulation performance evaluation result of the insulation layer of the polypropylene cable to be evaluated based on the insulation performance evaluation results of the slices at different positions. For example, if the insulation performance evaluation results of the slices at different positions are all characterized as good insulation performance and the remaining insulation life exceeds the design life, the insulation performance evaluation result of the insulation layer of the polypropylene cable to be evaluated can be that the overall insulation layer of the polypropylene cable to be evaluated is in good condition and meets the safety operation requirements.

[0066] In the above-mentioned polypropylene cable insulation performance evaluation method, the insulation performance of the insulation layer at different positions can be more accurately reflected through multi-layer slice analysis, which improves the comprehensiveness of the insulation performance evaluation. Combined with dielectric performance testing and simulation tools, the insulation performance can be evaluated from different angles, that is, the dielectric performance of each slice is tested, and the measured dielectric parameters can reflect the actual performance of the material. Then, the working state parameters of each slice under actual working conditions are simulated, and then the insulation performance of the insulation layer is more comprehensively evaluated by combining the dielectric parameters and the working state parameters, which improves the reliability of the insulation performance evaluation results, can identify potential insulation failures in advance, and improve the safety of cable use. In addition, by testing and evaluating the slices of the cable, the workload of the entire cable evaluation is reduced, and the evaluation efficiency is improved.

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

[0068] Step S302 , obtaining the remaining insulation service time corresponding to each slice according to the insulation failure cumulative loss value and the insulation tolerance index corresponding to each slice and the electric field intensity distribution at different positions in the radial direction of each slice.

[0069] Among them, the cumulative loss value of insulation failure may refer to the sum of the losses of the sliced ​​cable insulation material that reaches the insulation failure state due to factors such as electric field during use under preset conditions. The insulation tolerance index may refer to the index obtained by applying voltage test, which can reflect the bearing capacity of the insulating material under voltage. The higher the index, the better the stability of the insulating material under high voltage and the longer the remaining service life. The electric field strength distribution at different positions in the radial direction of each slice may refer to the electric field strength measured at different radial positions of the cable (such as the center, 1 / 4 radius, 1 / 2 radius, etc.). The higher the electric field strength, the greater the insulation loss may be, thus affecting the remaining insulation service life. The remaining insulation service life may refer to the remaining service life of the insulating layer of the slice.

[0070] Exemplarily, the server obtains the remaining insulation use time corresponding to each slice according to the insulation failure cumulative loss value and the insulation tolerance index corresponding to each slice and the electric field strength distribution at different positions in the radial direction of each slice. Specifically, the remaining insulation use time can be obtained by the following formula:

[0071]

[0072] in, It can refer to the cumulative insulation loss value corresponding to the slice. It can refer to the remaining insulation usage time corresponding to the slice. It can refer to the electric field intensity distribution at different positions in the radial direction of the slice. It can refer to the insulation tolerance index corresponding to the slice. The remaining insulation service time can be calculated by the above formula. .

[0073] Step S304, comparing the remaining insulation use time corresponding to each slice with the preset insulation use time, to obtain the insulation performance evaluation result corresponding to each slice for the electric field strength.

[0074] Exemplarily, the remaining insulation usage time corresponding to each slice is compared with the preset insulation usage time. When the remaining insulation usage time corresponding to the slice is greater than the preset insulation usage time, it can be concluded that the insulation performance evaluation result corresponding to the slice for the electric field strength meets the insulation requirements.

[0075] In this embodiment, by analyzing and calculating the insulation failure cumulative loss value corresponding to each slice, the insulation tolerance index and the electric field strength distribution at different positions in the radial direction of each slice, the remaining insulation service time is obtained, and compared with the preset insulation service time, the insulation performance of each slice can be accurately evaluated, and the actual performance of the insulation material of the slice under different electric field strengths can be obtained, which can improve the accuracy of the insulation performance evaluation of the slice.

[0076] In an exemplary embodiment, the working state parameters also include the working temperature distribution at different positions in the radial direction of each slice; Figure 3 As shown, step S208 may further include the following steps:

[0077] Step S402, obtaining the insulation heat aging time corresponding to each slice according to 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.

[0078] Among them, the operating temperature distribution may refer to the distribution of specific temperatures of slices at different radial positions under working conditions. The reaction activation energy corresponding to polypropylene may refer to the energy required for the polypropylene material in the slice to become activated during the thermal aging process, resulting in material degradation or degradation of material performance. Increased temperature will cause more molecules in the polypropylene material to obtain sufficient energy to cross the activation energy barrier, accelerating the aging process. The gas constant may refer to a physical constant, which is usually used in the ideal gas state equation and is often used in thermodynamics and chemical reactions to calculate temperature-related reaction rates and thermal aging processes. The insulation thermal aging time may refer to the time required for polypropylene insulation to undergo a thermal aging process at a specific operating temperature.

[0079] For example, the server can calculate the insulation heat aging time corresponding to each slice according to 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 through a formula, wherein the calculation formula can be as follows:

[0080]

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

[0082] Step S404, comparing the insulation thermal aging time of each slice with the preset insulation use time, to obtain the insulation performance evaluation result corresponding to each slice at the working temperature.

[0083] Exemplarily, the server compares the insulation thermal aging time of each slice with the preset insulation usage time. If the insulation thermal aging time of a slice is greater than the preset insulation usage time, the insulation performance evaluation result corresponding to the slice at the working temperature can be obtained as meeting the insulation requirements; if the insulation thermal aging time of another slice is less than or equal to the preset insulation usage time, that is, it means that the normal insulation effective time of the slice at the working temperature does not meet the preset insulation usage time, then the insulation performance evaluation result corresponding to the slice 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 more accurately evaluated. By understanding the temperature distribution and corresponding thermal aging characteristics at different positions, guidance can be provided for the improvement and optimization of the polypropylene insulation material and the overall performance of the polypropylene cable can be improved.

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

[0086] The step voltage test may refer to gradually increasing the voltage applied to the slice during the test to obtain the performance of the insulation state of the slice changing with the voltage.

[0087] Exemplarily, the server performs a stepped voltage test on each slice, and can apply a gradually increasing voltage to the slice by controlling a test device that can gradually adjust the voltage until the insulating material of the slice shows signs of insulation failure or the applied voltage reaches a preset threshold; then, by recording the loss at each voltage step, the loss suffered by the insulating material of the slice as the voltage increases is evaluated, and the cumulative insulation failure loss value and the insulation tolerance index corresponding to each slice are obtained.

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

[0089] In an exemplary embodiment, the working state parameters include the electric field strength distribution at different positions in the radial direction of each slice and the working temperature distribution at different positions in the radial direction; step S206 may include the following steps: inputting 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 obtaining the electric field strength distribution at different positions in the radial direction of each slice and the working temperature distribution at different positions in the radial direction 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 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 construct a simulation model for the polypropylene cable slice to be evaluated through the thickness parameters of each slice and the insulation layer parameter simulation tool, and then configure the simulation operating conditions according to the preset working current and the preset working voltage. After the simulation model is configured, a simulation analysis is performed, and the working temperature distribution at different positions in the radial direction is obtained by the heat transfer equation, and the electric field strength 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 an annular slicing device, dividing the polypropylene cable to be evaluated into multiple sub-insulating layers with different distances from the conductor layer according to the thickness of the insulating layer, to obtain multi-layer slices corresponding to the sub-insulating 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 may refer to a special tool for cutting cables, which can precisely control the cutting depth and angle to ensure that the cable is evenly cut into multiple layers. The cable insulation layer can be cut into multiple sub-insulation layers using the annular slicing device according to the set insulation layer thickness. The thickness of each sub-insulation layer and the 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 on one cross section of the cable, ensuring the continuity, consistency and comparability of data evaluation.

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

[0094] In this embodiment, the spatial charge distribution inside the dielectric can be detected and quantified by performing a spatial charge test on the slice, and the dielectric polarization change of the dielectric at a constant temperature and the influence of the internal trap on the charge movement can be understood by performing an isothermal relaxation test on the slice; then, based on the data of the spatial charge test and the isothermal relaxation test, the internal trap distribution state of the dielectric in the slice is analyzed, and the model can be used to calculate the internal trap distribution of the dielectric of different slices to determine the content, state and influence of the trap on the charge transport. Then, the internal trap distribution state of the dielectric is determined according to the internal trap distribution of the dielectric, that is, the internal trap distribution density of the dielectric and the internal trap distribution depth of the dielectric, and then the internal trap distribution density of the dielectric and the internal trap distribution depth of the dielectric are analyzed respectively. If the trap distribution density exceeds the threshold value and the trap distribution depth exceeds the threshold value, it means that the dielectric (insulating layer of the slice) is very easy to accumulate spatial charge at this time, and the accumulation of spatial charge is easy to cause insulation failure damage, so the insulation evaluation result corresponding to the slice can be obtained, which is that the position of the insulating layer of the slice in the polypropylene cable to be evaluated is easy to accumulate charge, which is easy to cause insulation failure damage, and relevant personnel need to pay more attention.

[0095] In a specific embodiment, Figure 4 As shown in FIG. 1 , the basic process of the polypropylene cable insulation performance evaluation method in this embodiment is shown. First, the research object is selected, that is, the cable entity of the AC polypropylene cable in different operating states. This embodiment is described by taking the cable without type test and the cable after type test as examples. A plurality of cable slices are obtained by a ring cable slicer, such as Figure 5 As shown, according to the different distances from the conductor, they are divided into inner layer samples, middle layer samples and outer layer samples (corresponding to the multi-layer slices of the insulation layer of the polypropylene cable to be evaluated). Then the dielectric performance test is carried out on different cable slices to obtain the measurement parameters, and the dielectric performance parameters of the cable slices (inner layer samples, middle layer samples, outer layer samples) at different positions are obtained. The actual operating conditions of the cable insulation materials at different positions, that is, the specific working environment, are obtained through the simulation research results. Then, combined with the dielectric performance parameters obtained by the above measurements, the performance changes of the cable slices at different positions are obtained, the overall performance status of the cable at the cable slice is analyzed, and the overall insulation material status of the cable is evaluated.

[0096] Figure 6The basic data processing flow of this embodiment is shown. Through the simulation software, the working state of the cable insulation material at different positions (inner layer sample, middle layer sample, outer layer sample) is calculated, that is, the working state of the insulation at the position is simulated and calculated, including the electric field strength at the position, the working temperature at the position, the external pressure at the position and other information. Through the dielectric performance tests of the cable slices such as breakdown test, conductivity test, space charge test, etc., the basic dielectric parameters of the cable slices at different positions are obtained, including information such as breakdown field strength, conductivity current, trap distribution, and space charge accumulation. Combined with the cable slice parameters and the simulation research results for comprehensive evaluation, the key state evaluation parameters such as the working state and remaining life of the cable slice at the position are obtained, that is, the state evaluation under the current environment, the remaining life under the current environment and other evaluation parameters. By integrating the state evaluation parameters obtained from the cable slices at different positions, the overall operating state of the cable at the slice (comprehensive state evaluation and remaining life of the cable at the slice) can be obtained.

[0097] Among them, 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 at different locations is different, and the requirements for insulation materials are slightly different. Figure 7 The figure shows the calculation results of the electric field strength of the cable insulation layer at different positions (the distribution of electric field strength at different positions in the radial direction in the slice). Figure 8 is the temperature of the cable insulation layer at different positions (the operating temperature distribution at different positions in the radial direction of the slice). Figure 7 as well as Figure 8 It can be seen that the part of the insulating material closest to the conductor layer is subjected to the greatest electric field strength. The higher the temperature, the more intense the aging process and the worse the performance. Under long-term electrical stress, the life of the insulating material can be expressed by the following formula:

[0098]

[0099] In the formula, Refers to the cumulative loss that causes insulation failure; Refers to insulation life; Refers to the working electric field strength (calculated based on the above simulation); is the insulation tolerance index. Except for the electric field strength, which is obtained through simulation calculation, all other data can be obtained through step voltage test. According to the above formula, the corresponding remaining life is calculated. , if it is higher than the design life , it can be considered that the insulation basically meets the insulation requirements. At the same time, it should be noted that this embodiment proposes to analyze and measure the inner layer, middle layer, and outer layer samples. Only when all of them meet the requirements can it be said that the insulation material of the cable basically meets the requirements.

[0100] In addition to considering the effect of electrical stress, the evaluation of insulation materials also needs to consider the effect of thermal stress. Under the action of long-term high temperatures, insulation materials will also undergo chemical reactions and deteriorate. The degradation of insulation materials under thermal effects can be described by the Arrhenius equation:

[0101]

[0102] In the formula, Represents the insulation thermal aging life, is the reaction activation energy corresponding to polypropylene, is the gas constant, Represents the aging temperature (working temperature). The insulation life of the insulation material is calculated by the above formula. If it is higher than the design life, it can be considered that the insulation material basically meets the requirements.

[0103] In addition to the basic life assessment, there are other factors that affect the dielectric properties of the insulation material, such as the distribution of traps inside the dielectric, etc. Therefore, this embodiment will also perform space charge measurement and isothermal relaxation test on the cable slice to further evaluate the dielectric insulation state. Fig. 9 This is the structural diagram of the 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 charge accumulation is measured by a piezoelectric sensor, an amplifier, an oscilloscope, and a calculator, because the change in voltage can reflect the accumulation of charge in the sample (slice). Fig.10 The structure diagram of the system for measuring the distribution of internal traps is shown in the figure. The voltage at both ends of the slice between the high voltage pole and the measuring pole is controlled by a programmable DC power supply. The safety of the measurement process is ensured by setting a protective pole on the slice. The tiny current is measured by the pA ammeter measuring pole, and then the trap state and distribution inside the dielectric can be inferred by the measured tiny current. The space charge test conducted by the space charge measurement system can reflect the distribution of traps inside the dielectric through the charge accumulation situation, and the isothermal relaxation current qualitatively studies the distribution inside the dielectric by analyzing the depolarization current. In the solid dielectric aging theory, the dielectric can be equivalent to three pairs of parallel resistors and capacitors, representing three polarization processes inside the dielectric, including solid insulator polarization, interface polarization between amorphous and crystalline, and various defects introduced by aging, such as polarization of metal salts and hydrated ions. Based on the above theory, the isothermal relaxation current of the dielectric can be fitted with a three-exponential function.

[0104]

[0105] in, Used to characterize the body polarization of insulating dielectrics; Used to characterize the existence of amorphous and crystalline polarization in dielectrics themselves; Used to characterize the polarization of metal salts, hydrated ions, and various defects caused by aging. It is related to the properties of the insulating material itself. Related to insulation degradation.

[0106] According to Simmons isothermal relaxation theory, the depolarization current and trap levels And the trap density has the following relationship:

[0107]

[0108]

[0109] In the formula, is the bottom energy level of the conduction band; is the trap energy level; is the Boltzmann constant; is temperature; is the escape frequency; The energy level occupied by the initial electron; is a trap level. Therefore, The figure provides an intuitive analysis of the trap distribution inside the dielectric.

[0110] Through the above analysis, we can get the distribution state of traps inside the dielectric. If the trap distribution density is extremely large and the depth is extremely deep, it means that space charge is very easy to accumulate inside the dielectric. The accumulation of space charge is easy to cause insulation failure. Therefore, engineers must pay more attention to the cables at 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 state parameters of AC polypropylene cables based on cable slices. This method uses cable slices as the research object, so that the research results have reference significance for engineering practice. At the same time, slice research is simpler than cable body testing. This embodiment is based on the evaluation of the remaining life of the insulating material, and combined with the calculation of the trap energy level distribution, the scope of consideration is relatively wide, so that the evaluation results have certain practicality. Therefore, this embodiment has certain practicality and innovation.

[0112] In traditional technology, a cable insulation material status assessment method is used to prepare samples by cable hot pressing. This method performs aging treatment on sheet samples pressed from granules under different conditions and compares them with untreated samples to obtain the degradation law of dielectric properties of cable insulation materials under different aging conditions. The above method has the advantages of simple operation, rapidity and effectiveness. Because most of its test items can use existing measuring equipment, the measurement of sheet samples is also very concise and effective. Its disadvantage is that sheet samples are actually somewhat different from cable insulation materials, and the results obtained cannot be completely matched with the actual cable operation status, and the practical value in engineering practice is low. Specifically, the hot pressing process is easily affected by the environment, and different cooling temperatures have an important influence on the crystallization of the samples. Even for samples made from the same batch, their performance is slightly different due to objective factors. This is reflected in the fact that the same batch of samples have different insulation properties during the test. Therefore, it is difficult to separate the sample preparation factors from the aging factors in the aging test, which makes the data analysis inaccurate. At the same time, the samples made by the hot pressing method also have performance differences with the power cable insulation materials in actual operation. The actual operation of the cable is affected by many common factors, including not only electric and thermal factors, but also pressure, air, humid environment and other factors. In addition, the cable will also cause a series of effects on the insulation material during the extrusion process. Therefore, the hot pressing method cannot accurately match the samples made by the hot pressing method with the insulation materials in actual operation. Although the basic insulation properties of the insulation materials can be obtained by studying the samples made by the hot pressing method, the difference between them and the actual cable insulation materials determines that the research results obtained by the hot pressing method have limited reference value for engineering practice.

[0113] A cable insulation material status assessment method for testing the cable as a whole. This method measures the overall dielectric properties of different cables under different actual operating conditions to evaluate the dielectric property change patterns of cable insulation materials under different operating environments. The advantage of this method is that it can fully correspond to the performance parameters of cable insulation materials under different operating conditions, which has important reference value for actual engineering. However, its disadvantage is that the equipment required for testing the dielectric parameters of the cable body usually needs to be temporarily built, and the test method is relatively shrink-proof, the equipment is relatively large, and the measurement flexibility is insufficient, and a large amount of manpower and material resources are usually required for comprehensive testing.

[0114] In summary, the sample preparation and measurement process of the hot pressing method is relatively simple, but its disadvantage is that it is impossible to directly relate the aging state of the prepared sample to the state of the cable in operation on site; the cable overall measurement method can directly reflect the operating state of the cable, but the cable overall measurement method is relatively complex and cumbersome, and requires a lot of manpower and material resources to build a measurement system. Compared with the hot pressing method research, the method proposed in this embodiment has the advantage that the obtained test parameter results are more accurate and can better correspond to the performance parameters of the cable during actual operation; compared with the cable body measurement, its advantage is that the test method is relatively simple and only requires existing measurement equipment for sheet samples.

[0115] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0116] Based on the same inventive concept, the embodiment of the present application also provides a polypropylene cable insulation performance evaluation device for implementing the polypropylene cable insulation performance evaluation method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more polypropylene cable insulation performance evaluation device embodiments provided below can refer to the limitations of the polypropylene cable insulation performance evaluation method above, and will not be repeated here.

[0117] In an exemplary embodiment, Fig.11 As shown, a polypropylene cable insulation performance evaluation device is provided, including: 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 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 tests on each slice to obtain dielectric parameters corresponding to each slice;

[0120] A working state parameter acquisition module 903 is used to simulate each slice through a simulation tool to obtain 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 corresponding to each slice according to 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; and is also used to obtain the insulation performance evaluation results of the insulation layer of the polypropylene cable to be evaluated according to the insulation performance evaluation results corresponding to each slice.

[0122] In an exemplary embodiment, the working state parameters include the electric field strength distribution at different positions in the radial direction of each slice; the dielectric parameters include the insulation failure cumulative loss value and the insulation tolerance index corresponding to each slice; the above-mentioned insulation performance evaluation module 904 is also used to obtain the remaining insulation service time corresponding to each slice according to the insulation failure cumulative loss value and the insulation tolerance index corresponding to each slice and the electric field strength distribution at different positions in the radial direction of each slice; 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 strength.

[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 above-mentioned insulation performance evaluation module 904 is also used to obtain the insulation thermal aging time corresponding to each slice according to 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; the insulation thermal aging time of each slice is compared with the preset insulation use 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 insulation failure cumulative loss value and the insulation tolerance index corresponding to each slice; the above-mentioned dielectric parameter acquisition module 902 is also used to perform a step voltage test on each slice to obtain the insulation failure cumulative loss value and the insulation tolerance index corresponding to each slice.

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

[0126] In an exemplary embodiment, the working state parameter acquisition module 903 is also 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 strength distribution at different positions in the radial direction of each slice and the working temperature distribution at different positions in the radial direction 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 also used 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 through a ring-shaped slicing device, so as 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.

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

[0129] Each module in the above-mentioned polypropylene cable insulation performance evaluation device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0130] In an exemplary embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as shown in FIG. Fig.12 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for evaluating the insulation performance of a polypropylene cable is implemented.

[0131] Those skilled in the art will understand that Fig.12The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0132] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, 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, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[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] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present 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. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0136] The technical features of the above embodiments may be combined arbitrarily. 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 above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for evaluating the insulation performance of polypropylene cables. It is characterized in that The method comprises: Obtain multi-layer slices of the insulation layer of the polypropylene cable to be evaluated; the polypropylene cable comprises a conductor layer and an insulation layer; each of the slices corresponds to an insulation layer portion of the polypropylene cable at a different distance from the conductor layer; Performing a dielectric property test on each of the slices to obtain dielectric parameters corresponding to each of the slices; Simulating each of the slices by a simulation tool to obtain working state parameters of the insulating material at different positions in the radial direction of each of the slices; Obtaining insulation performance evaluation results corresponding to each of the slices according to dielectric parameters corresponding to each of the slices and / or working state parameters of the insulating material at different positions in the radial direction of each of the slices; The insulation performance evaluation result of the insulation layer of the polypropylene cable to be evaluated is obtained according to the insulation performance evaluation result corresponding to each of the slices.

2. The method according to claim 1, It is characterized in that The working state parameters include the electric field intensity distribution at different positions in the radial direction of each slice; the dielectric parameters include the insulation failure cumulative loss value and the insulation tolerance index corresponding to each slice; The step of obtaining the insulation performance evaluation result corresponding to each of the slices according to the dielectric parameters corresponding to each of the slices and / or the working state parameters of the insulating material at different positions in the radial direction of each of the slices comprises: According to the insulation failure cumulative loss value and the insulation tolerance index corresponding to each of the slices and the electric field intensity distribution at different positions in the radial direction of each of the slices, the remaining insulation service time corresponding to each of the slices is obtained; The remaining insulation use time corresponding to each of the slices is compared with the preset insulation use time to obtain the insulation performance evaluation result corresponding to each of the slices with respect to the electric field strength.

3. The method according to claim 2, It is characterized in that The working state parameters also include working temperature distribution at different positions in the radial direction of each slice; The step of obtaining the insulation performance evaluation result corresponding to each of the slices according to the dielectric parameters corresponding to each of the slices and / or the working state parameters of the insulating material at different positions in the radial direction of each of the slices comprises: According to 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, the insulation heat aging time corresponding to each slice is obtained; The insulation thermal aging time of each of the slices is compared with the preset insulation use time to obtain the insulation performance evaluation results corresponding to each of the slices at the working temperature.

4. The method according to claim 2, It is characterized in that The dielectric parameters include the insulation failure cumulative loss value and the insulation tolerance index corresponding to each of the slices; The performing of dielectric property testing on each of the slices to obtain dielectric parameters corresponding to each of the slices includes: A step voltage test is performed on each of the slices to obtain an insulation failure cumulative loss value and an insulation tolerance index corresponding to each of the slices.

5. The method according to claim 3, It is characterized in that The working state parameters include the electric field intensity distribution at different positions in the radial direction in each of the slices and the working temperature distribution of the electric field intensity distribution at different positions in the radial direction; The simulating each of the slices by a simulation tool to obtain the working state parameters of the insulating material at each position in each of the slices includes: The preset working current, preset working voltage, thickness parameters of each slice and insulation layer parameters of the polypropylene cable to be evaluated are input into the simulation tool, and the electric field intensity distribution at different positions in the radial direction and the working temperature distribution at different positions in the radial direction of each slice are obtained through simulation analysis; The insulation layer parameters are related to the thermal conductivity properties of polypropylene.

6. The method according to claim 1, It is characterized in that The method of obtaining a multi-layer slice of the insulation layer of the polypropylene cable to be evaluated comprises: The polypropylene cable to be evaluated is divided into a plurality of sub-insulating layers having different distances from the conductor layer according to the thickness of the insulating layer by an annular slicing device to obtain multi-layer slices corresponding to the sub-insulating layers; each of the slices is located in the same cross section of the polypropylene cable to be evaluated.

7. The method according to claim 1, It is characterized in that The method further comprises: A space charge test and an isothermal relaxation test are performed on each of the slices to obtain a distribution state of traps inside the dielectric corresponding to each of the slices. A distribution density analysis and a distribution depth analysis are performed based on the distribution state of traps inside the dielectric to obtain an insulation evaluation result of each of the slices.

8. A polypropylene cable insulation performance evaluation device, It is characterized in that The device comprises: A slice acquisition module is used to obtain multi-layer slices of the insulation layer of the polypropylene cable to be evaluated; the polypropylene cable includes a conductor layer and an insulation layer; each of the slices corresponds to an insulation layer portion of the polypropylene cable at a different distance from the conductor layer; A dielectric parameter acquisition module, used to perform a dielectric property test on each of the slices to obtain dielectric parameters corresponding to each of the slices; A working state parameter acquisition module, used to simulate each of the slices through a simulation tool to obtain working state parameters of the insulating material at different positions in the radial direction of each of the slices; The insulation performance evaluation module is used to obtain the insulation performance evaluation results corresponding to each of the slices according to the dielectric parameters corresponding to each of the slices and / or the working state parameters of the insulating material at different positions in the radial direction of each of the slices; and is also used to obtain the insulation performance evaluation results of the insulation layer of the polypropylene cable to be evaluated according to the insulation performance evaluation results corresponding to each of the slices.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program. It is characterized in that When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, It is characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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