Evaluation method and system for ablation risk of buffer layer of high-voltage corrugated aluminum sheath cable

Abstract

The invention discloses a method and a system for evaluating the ablation risk of a buffer layer of a high-voltage corrugated aluminum sheath cable. The method comprises the following steps: determining the initial ablation temperature of the buffer layer of a to-be-tested cable; measuring a first resistance value between the buffer layer of the to-be-measured cable and the aluminum sheath when the operation temperature of the buffer layer of the to-be-measured cable reaches the initial ablation temperature of the buffer layer; taking the buffer layer and the aluminum sheath of the to-be-tested cable as a test positive electrode and a test negative electrode respectively, applying test voltage, and measuring to obtain a second resistance value between the buffer layer and the aluminum sheath of the to-be-tested cable; and calculating the ratio of the second resistance value to the first resistance value to obtain a buffer layer ablation risk coefficient, and judging the size relationship between the buffer layer ablation risk coefficient and a preset threshold value to determine whether the buffer layer of the to-be-detected cable has an ablation risk. The method can accurately evaluate the ablation risk of the cable buffer layer.

Description

Technical Field

[0001] The invention relates to the technical field of cable ablation risk assessment, and in particular to a method and system for assessing ablation risk of a buffer layer of a high-voltage corrugated aluminum sheathed cable. Background Art

[0002] With the development of urban power grids and the increasing shortage of land resources, high-voltage cables are increasingly widely used, and their insulation status is directly related to the reliability and stability of the entire power network. In recent years, high-voltage cable buffer layer ablation failures have occurred frequently. There are ablation marks on the semi-conductive buffer water-blocking layer (referred to as the buffer layer) and white powder is precipitated at the defect, gradually deteriorating the main insulation of the cable and eventually causing insulation breakdown. The buffer layer ablation defect is highly latent, the defect development process is very long, and the scope of action is large, which has a serious impact on the safe operation of urban power transmission networks.

[0003] Current research on the buffer layer ablation defect is that the resistivity change of the damp semiconductor water buffer layer strip leads to poor contact between the corrugated aluminum sheath and the insulating shielding layer, generating local electric field distortion at the contact point between the corrugated aluminum sheath trough and the insulating shielding layer, gradually deteriorating the main insulation of the high-voltage cable.

[0004] At present, the buffer layer ablation risk assessment method is based on multiple assessment factors such as the volume resistivity and moisture content of the cable buffer layer, and performs a fuzzy comprehensive assessment of the buffer layer state. The improved analytic hierarchy process is used to assign weights to each assessment factor, and then the state of the buffer layer is assessed, thereby assessing the risk of buffer layer ablation. This method involves many and complex assessment factors, and the assessment factors do not include the evaluation of the contact state between the cable aluminum sheath and the buffer layer. The resulting buffer layer state assessment method has no direct connection with buffer layer ablation, so it is impossible to accurately assess the risk of buffer layer ablation. Summary of the invention

[0005] The present invention aims to solve the technical problems in the related art at least to a certain extent. To this end, the first object of the present invention is to provide a method for evaluating the ablation risk of the buffer layer of a high voltage corrugated aluminum sheathed cable, which method can accurately evaluate the ablation risk of the buffer layer.

[0006] The second object of the present invention is to provide a system for evaluating the risk of ablation of the buffer layer of a high-voltage corrugated aluminum sheathed cable.

[0007] A third object of the present invention is to provide a computer-readable storage medium.

[0008] A fourth object of the present invention is to provide an electronic device.

[0009] To achieve the above object, the present invention is implemented through the following technical solutions:

[0010] A method for evaluating the ablation risk of a buffer layer of a high-voltage corrugated aluminum sheathed cable, comprising:

[0011] Determine the starting ablation temperature of the buffer layer of the cable to be tested;

[0012] Measuring a first resistance value between the buffer layer and the aluminum sheath of the cable to be tested when the operating temperature of the buffer layer of the cable to be tested reaches the starting ablation temperature of the buffer layer;

[0013] The buffer layer and the aluminum sheath of the cable to be tested are used as the positive and negative electrodes of the test respectively, a test voltage is applied, and a second resistance value between the buffer layer and the aluminum sheath of the cable to be tested is measured;

[0014] The ratio of the second resistance value to the first resistance value is calculated to obtain a buffer layer ablation risk coefficient, and the magnitude relationship between the buffer layer ablation risk coefficient and a preset threshold is determined to determine whether there is ablation risk for the buffer layer of the cable to be tested.

[0015] Preferably, determining the initial ablation temperature of the buffer layer of the cable to be tested includes:

[0016] Taking the buffer layer of the cable to be tested with a preset length as a test sample, and recording the surface morphology of the test sample before heating;

[0017] Based on the set temperature gradient, the test piece is heated for a preset time in sequence, and after each heating is completed, the surface morphology of the test piece is compared with the surface morphology of the test piece before heating to determine the starting ablation temperature of the buffer layer of the cable to be tested.

[0018] Preferably, measuring a first resistance value between the buffer layer and the aluminum sheath of the cable to be tested when the operating temperature of the buffer layer of the cable to be tested reaches the buffer layer starting ablation temperature includes:

[0019] Determine the resistivity of the buffer layer of the cable to be tested at different deformation distances;

[0020] Determine the current density and temperature field of the buffer layer under different interference fit distances and different numbers of poor contact points of the cable to be tested, and determine the interference fit distance and the number of poor contact points when the operating temperature of the buffer layer reaches the starting ablation temperature of the buffer layer based on the determined current density and temperature field of the buffer layer;

[0021] The first resistance value is determined based on the resistivity of the buffer layer of the cable to be tested at different deformation distances, the interference fit distance when the operating temperature of the buffer layer reaches the initial ablation temperature of the buffer layer, and the number of poor contact points.

[0022] Preferably, determining the current density and temperature field of the buffer layer of the tested cable at different interference fit distances and different numbers of poor contact points includes:

[0023] Obtaining the physical parameter values ​​of each layer of the cable to be tested, the physical parameters at least including relative dielectric constant, resistivity, thermal conductivity, constant pressure heat capacity, density and outer diameter parameters;

[0024] An electrothermal coupling field simulation model of the cable to be tested is established based on the physical parameter values ​​of each layer of the cable to be tested;

[0025] Obtaining the annual flow rate, ambient temperature, convection heat dissipation coefficient and voltage level parameters of the cable to be tested, so as to determine the boundary conditions of the electrothermal coupling field simulation model;

[0026] The electrothermal coupling field simulation model is solved based on the boundary conditions to obtain the buffer layer current density and temperature field under different interference fit distances and different numbers of poor contact points of the cable to be tested.

[0027] Preferably, determining the resistivity of the buffer layer of the cable to be tested at different deformation distances includes:

[0028] Take a buffer layer of a preset area and preset thickness as a sample;

[0029] Applying pressure to the sample and recording the deformation distance of the sample;

[0030] The resistance value of the sample at different deformation distances is measured to obtain the resistivity of the buffer layer of the cable to be tested at different deformation distances.

[0031] Preferably, the interference fit distance is the radial distance that the aluminum sheath of the cable to be tested is pressed into the buffer layer of the cable to be tested; the number of poor contact points is the number of troughs where the aluminum sheath of the cable to be tested is not in contact with the buffer layer of the cable to be tested.

[0032] Preferably, judging the magnitude relationship between the buffer layer ablation risk coefficient and a preset threshold value to determine whether the buffer layer of the cable to be tested has ablation risk includes:

[0033] When the buffer layer ablation risk coefficient is greater than a preset threshold, it is determined that the buffer layer of the cable under test has ablation risk; otherwise, it is determined that the buffer layer of the cable under test has no ablation risk.

[0034] To achieve the above object, the second aspect of the present invention provides an evaluation system for the ablation risk of a buffer layer of a high-voltage corrugated aluminum sheathed cable, comprising:

[0035] A determination module, used to determine the starting ablation temperature of the buffer layer of the cable to be tested;

[0036] A first measuring module is used to measure a first resistance value between the buffer layer and the aluminum sheath of the cable to be tested when the operating temperature of the buffer layer of the cable to be tested reaches the starting ablation temperature of the buffer layer;

[0037] The second measuring module is used to use the buffer layer and the aluminum sheath of the cable to be tested as the positive and negative electrodes of the test respectively, apply a test voltage, and measure a second resistance value between the buffer layer and the aluminum sheath of the cable to be tested;

[0038] A calculation module, used for calculating the ratio of the second resistance value to the first resistance value to obtain a buffer layer ablation risk coefficient;

[0039] A judgment module, used to judge the magnitude relationship between the buffer layer ablation risk coefficient and a preset threshold;

[0040] The evaluation module is used to determine whether the buffer layer of the cable to be tested has a risk of ablation based on the size relationship judgment result.

[0041] To achieve the above objectives, the third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for evaluating the risk of ablation of the buffer layer of a high-voltage corrugated aluminum sheathed cable.

[0042] To achieve the above-mentioned purpose, the fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method for evaluating the ablation risk of the buffer layer of the high-voltage corrugated aluminum sheathed cable is implemented.

[0043] The present invention has at least the following technical effects:

[0044] (1) The evaluation method proposed in the present invention has practical physical significance, rather than a combination of multiple evaluation factors through weights. Since the main reason for the ablation of the buffer layer of the corrugated aluminum sheath is the poor electrical contact between the aluminum sheath and the buffer layer, the present invention accurately reflects the electrical contact state between the two by the resistance value between the two. By reaching the starting ablation temperature of the buffer layer, the electrical contact state is limited, and the limit value of the resistance value between the aluminum sheath and the buffer layer of the cable to be tested, that is, the buffer layer ablation risk coefficient, is obtained. The buffer layer ablation risk is evaluated in this way, which can improve the accuracy of the evaluation result.

[0045] (2) The traditional method needs to perform multiple test items on the cable during evaluation, and the process is complicated and easily causes certain damage to the cable. However, in actual engineering, the present invention only needs to measure the resistance value between the aluminum sheath and the buffer layer, which has little damage to the cable to be tested. Therefore, the present invention is simple to apply in actual engineering, has little damage to the sample to be tested, and has excellent economic efficiency. In addition, the evaluation method of the present invention only needs to detect the resistance value between the buffer layer and the aluminum sheath of the cable to be tested, which is easy to operate and has high reliability and repeatability.

[0046] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The present invention is a flowchart of a method for evaluating the ablation risk of a buffer layer of a high-voltage corrugated aluminum sheathed cable according to an embodiment of the present invention.

[0048] Figure 2 Schematic diagram of the structure of a cable to be tested according to an embodiment of the present invention.

[0049] Figure 3 It is a partial schematic diagram of the buffer layer of the cable to be tested according to an embodiment of the present invention.

[0050] Figure 4 Schematic diagram of a resistance calculation circuit model according to an embodiment of the present invention.

[0051] Figure 5 It is a simplified schematic diagram of a resistance calculation circuit model according to an embodiment of the present invention.

[0052] Figure 6 Schematic diagram of a second resistance value test according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The present embodiment is described in detail below, and examples of the embodiment are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0054] The following describes the method and system for evaluating the ablation risk of the buffer layer of the high-voltage corrugated aluminum sheathed cable of this embodiment with reference to the accompanying drawings.

[0055] Figure 1 Flow chart of the method for evaluating the risk of ablation of the buffer layer of a high-voltage corrugated aluminum sheathed cable according to an embodiment of the present invention. Figure 1 As shown, the method includes:

[0056] Step S1: determining the initial ablation temperature of the buffer layer of the cable to be tested.

[0057] In this embodiment, the structural diagram of the cable to be tested is as follows: Figure 2 As shown, the cable to be tested includes a conductor 1, a conductor shielding layer 2, an XLPE (cross-linked polyethylene) insulating layer 3, an insulating shielding layer 4, a buffer layer 5, a corrugated aluminum sheath 6, an air layer 7 and an outer sheath 8. It should be noted that the main purpose of this embodiment is to determine the initial ablation temperature of the buffer layer.

[0058] In one embodiment of the present invention, determining the starting ablation temperature of the buffer layer of the cable to be tested includes:

[0059] Step S11: taking the buffer layer of the cable to be tested with a preset length as a test sample, and recording the surface morphology of the test sample before heating.

[0060] Step S12: Based on the set temperature gradient, the test piece is heated for a preset time in sequence, and after each heating is completed, the surface morphology of the test piece is compared with the surface morphology of the test piece before heating to determine the starting ablation temperature of the buffer layer of the cable to be tested.

[0061] Specifically, the buffer layer of the cable to be tested with a preset length can be used as a test sample, and the surface morphology of the buffer layer before ablation can be recorded. Then, the temperature gradient is set at 5°C, and the buffer layer is heated in an oven for 24 hours (a longer heating time is set because the ablation change of the buffer layer is not obvious when the heating time is short) to test the initial ablation temperature of the buffer layer. The surface morphology of the buffer layer after heating of the test sample is recorded and compared with the surface morphology of the buffer layer before heating to determine the initial ablation temperature of the buffer layer of the cable to be tested.

[0062] Step S2: measuring a first resistance value between the buffer layer and the aluminum sheath of the cable to be tested when the operating temperature of the buffer layer of the cable to be tested reaches the initial ablation temperature of the buffer layer.

[0063] In this embodiment, measuring the first resistance value between the buffer layer and the aluminum sheath of the cable to be tested when the operating temperature of the buffer layer of the cable to be tested reaches the starting ablation temperature of the buffer layer includes:

[0064] Step S21: determining the resistivity of the buffer layer of the cable to be tested at different deformation distances.

[0065] Among them, determining the resistivity of the buffer layer of the cable to be tested at different deformation distances includes: taking a buffer layer of a preset area and a preset thickness as a sample; applying pressure to the sample and recording the deformation distance of the sample; measuring the resistance value of the sample at different deformation distances, so as to obtain the resistivity of the buffer layer of the cable to be tested at different deformation distances.

[0066] Specifically, a buffer layer with a preset area of ​​S and a preset thickness of h1 can be taken as a sample, and pressure is applied to it by a press, and its deformation distance x is measured by a height gauge, and its resistance value R(x) at different deformation distances is measured by a multimeter. The deformation characteristics of the resistivity of the buffer layer are calculated according to the resistance value, sample size and deformation distance, and its resistivity ρ(x) at different deformation distances is:

[0067]

[0068] Step S22: Determine the current density and temperature field of the buffer layer under different interference fit distances and different numbers of poor contact points of the cable to be tested, and determine the interference fit distance and the number of poor contact points when the buffer layer operating temperature reaches the buffer layer starting ablation temperature based on the determined buffer layer current density and temperature field.

[0069] Figure 3 Figure 1 is a partial schematic diagram of the buffer layer of the cable to be tested. Figure 3 As shown, the interference fit distance is the radial distance that the aluminum sheath of the cable to be tested is pressed into the buffer layer of the cable to be tested, that is, x1; the number of poor contact points is the number of troughs where the aluminum sheath of the cable to be tested is not in contact with the buffer layer of the cable to be tested, that is, the number of troughs in area 12.

[0070] In this embodiment, determining the current density and temperature field of the buffer layer of the tested cable at different interference fit distances and different numbers of poor contact points includes:

[0071] Step S221: obtaining the physical parameter values ​​of each layer of the cable to be tested, where the physical parameters at least include relative dielectric constant, resistivity, thermal conductivity, constant-pressure heat capacity, density and outer diameter parameters.

[0072] Step S222: establishing an electrothermal coupling field simulation model of the cable to be tested based on the physical parameter values ​​of each layer of the cable to be tested.

[0073] Step S223: Obtain the annual flow rate, ambient temperature, convection heat dissipation coefficient and voltage level parameters of the cable to be tested, so as to determine the boundary conditions of the electrothermal coupling field simulation model.

[0074] Step S224: Solve the electrothermal coupling field simulation model based on the boundary conditions to obtain the buffer layer current density and temperature field under different interference fit distances and different numbers of poor contact points of the cable to be tested.

[0075] Specifically, the relative dielectric constant, resistivity, thermal conductivity, constant pressure heat capacity, density and outer diameter parameters of the physical layers of the cable conductor, conductor shield, XLPE insulation, insulation shield, buffer layer, aluminum sheath and outer sheath to be tested can be collected first, and then the electrothermal coupling field simulation model of a single contact point of the cable to be tested can be established. Furthermore, the annual flow rate, ambient temperature, convection heat dissipation coefficient and voltage level parameters of the cable to be tested are collected as boundary conditions of the electrothermal coupling field simulation model. Afterwards, the buffer layer current density and temperature field of the electrothermal coupling field simulation model are calculated based on the boundary conditions to obtain the buffer layer current density and temperature field under different interference fit distances and different numbers of poor contact points, and the interference fit distance x1 and the number of poor contact points n when the operating temperature reaches the starting ablation temperature of the buffer layer are recorded.

[0076] Step S23: determining a first resistance value based on the resistivity of the buffer layer of the cable to be tested at different deformation distances, the interference fit distance when the operating temperature of the buffer layer reaches the initial ablation temperature of the buffer layer, and the number of poor contact points.

[0077] Specifically, a resistance calculation circuit model between the buffer layer and the aluminum sheath of the cable to be tested is established, as shown in FIG. Figure 4 As shown, the number of aluminum sheath nodes, that is, the total number of contact points, N = L / γ (L is the length of the cable to be tested, γ is the pitch of the aluminum sheath). In order to make the resistance value corresponding to the initial ablation temperature of the buffer layer more stringent, it is assumed that the good contact points are all close to the network port, that is, Figure 4 shown. Figure 4 In the figure, the total number of contact points is 1 poor contact point on the right side of R1 plus 1 good contact point on the right side of R3, so the total number of contact points N = 2, of which there is 1 poor contact point on the right side of R1, so n = 1. Therefore, the number of resistors R1 is N / 2+n, which is 2, and the number of resistors R2 is 2N, which is 4. Therefore, the number of poor contact points n determines the number of resistors R1 in the resistance calculation circuit model, so it affects the equivalent resistance R.

[0078] Furthermore, according to the parameters of the volume resistivity of the buffer layer, the interference fit distance x1 between the buffer layer and the aluminum sheath, and the number of poor contact points n, the resistance values ​​of the resistors R1, R2, and R3 in the circuit are calculated, and then the equivalent resistance R of the local cable section is obtained.

[0079]

[0080]

[0081] l=l1-l2 (4)

[0082]

[0083]

[0084]

[0085] Among them, since the aluminum sheath is corrugated and can be similar to a sine function, Figure 2The horizontal axis represents the angle, so l1 and l2 are the coordinate values ​​of the two good contact points on the upper surface of the aluminum sheath and the buffer layer, which are expressed as angles; arcsin is the inverse sine function; h2 is the corrugation depth of the aluminum sheath; l is the axial distance of the aluminum sheath pressed into the buffer layer; R1 is the radial resistance of the part of the buffer layer that is not in contact with the aluminum sheath, R2 is the axial resistance between each contact point of the buffer layer, and R3 is the radial resistance of the part of the buffer layer in contact with the aluminum sheath; x is the deformation distance of the buffer layer; r is the distance from any point in the radial direction of the buffer layer to the insulating shielding layer; r1 and r2 are the outer diameters of the insulating shielding layer and the outer diameters of the buffer layer, respectively; ρ(x1) is the resistivity when the deformation distance is x1, and ρ(x=0) is the resistivity when the deformation distance is 0. Therefore, based on the resistance values ​​of resistors R1, R2 and R3, the equivalent circuit diagram can be used, that is, Figure 4 The equivalent resistance R between the buffer layer and the aluminum sheath of the cable to be tested is obtained.

[0086] Furthermore, the resistance calculation circuit model is simplified, such as Figure 5 As shown, the network port resistance R after the Mth simplification M The network port resistance R after M-1 simplification M-1 The relationship between R M =(R M-1 +2R2) / / R3. Thus, according to the recursive relationship and the interference fit distance x1 and the number of poor contact points n obtained when the operating temperature reaches the starting ablation temperature of the buffer layer, the first resistance value R0 between the aluminum sheath and the buffer layer of the entire cable under test is obtained when the operating temperature reaches the starting ablation temperature of the buffer layer.

[0087] Step S3: using the buffer layer and the aluminum sheath of the cable to be tested as the positive and negative electrodes for testing respectively, applying a test voltage, and measuring a second resistance value between the buffer layer and the aluminum sheath of the cable to be tested.

[0088] Figure 6 This is a schematic diagram for testing the second resistance value. Figure 6 As shown, the buffer layer and aluminum sheath of the cable to be tested are used as the positive and negative electrodes of the test respectively, and the multimeter is connected. The test voltage is slowly increased until it is sufficient to obtain a current reading, and a second resistance value R4 between the two is obtained.

[0089] Step S4: Calculate the ratio of the second resistance value to the first resistance value to obtain a buffer layer ablation risk coefficient, and determine the relationship between the buffer layer ablation risk coefficient and a preset threshold value to determine whether the buffer layer of the cable to be tested has ablation risk.

[0090] Among them, the relationship between the buffer layer ablation risk coefficient and the preset threshold is judged to determine whether the buffer layer of the cable under test has ablation risk, including: when the buffer layer ablation risk coefficient is greater than the preset threshold, it is determined that the buffer layer of the cable under test has ablation risk; otherwise, it is determined that the buffer layer of the cable under test does not have ablation risk.

[0091] Specifically, the buffer layer ablation risk coefficient, i.e., R4 / R0, is obtained by calculating the ratio of the second resistance value to the first resistance value. The larger the coefficient, for example, when it is greater than a preset threshold, the more likely the buffer layer is to be at risk of ablation. Conversely, the buffer layer of the cable to be tested is not likely to be at risk of ablation.

[0092] Therefore, the ablation risk assessment method proposed in this embodiment accurately reflects the electrical contact state between the buffer layer and the aluminum sheath, and evaluates the ablation risk of the tested cable in a physical sense.

[0093] Furthermore, the present invention also provides a system for evaluating the ablation risk of a buffer layer of a high-voltage corrugated aluminum sheathed cable, comprising a determination module, a first measurement module, a second measurement module, a calculation module, a judgment module and an evaluation module connected in sequence.

[0094] Among them, the determination module is used to determine the starting ablation temperature of the buffer layer of the cable to be tested; the first measurement module is used to measure the first resistance value between the buffer layer and the aluminum sheath of the cable to be tested when the operating temperature of the buffer layer reaches the starting ablation temperature of the buffer layer; the second measurement module is used to use the buffer layer and the aluminum sheath of the cable to be tested as the positive and negative electrodes of the test respectively, apply the test voltage, and measure the second resistance value between the buffer layer and the aluminum sheath of the cable to be tested; the calculation module is used to calculate the ratio of the second resistance value to the first resistance value to obtain the buffer layer ablation risk coefficient; the judgment module is used to judge the size relationship between the buffer layer ablation risk coefficient and a preset threshold; the evaluation module is used to determine whether there is a risk of ablation of the buffer layer of the cable to be tested based on the judgment result of the size relationship.

[0095] It should be noted that the specific implementation of the system for evaluating the ablation risk of the buffer layer of the high-voltage corrugated aluminum sheathed cable in the embodiment of the present invention can refer to the specific implementation of the method for evaluating the ablation risk of the buffer layer of the high-voltage corrugated aluminum sheathed cable mentioned above. To avoid redundancy, it will not be repeated here.

[0096] In summary, the evaluation method proposed in the present invention has practical physical significance, rather than a combination of multiple evaluation factors through weights. Since the main reason for the ablation of the buffer layer of the corrugated aluminum sheath is the poor electrical contact between the aluminum sheath and the buffer layer, the present invention accurately reflects the electrical contact state between the two with the resistance value between the two. The buffer layer reaches the starting ablation temperature, the electrical contact state is limited, and the limit of the resistance value between the aluminum sheath and the buffer layer of the cable to be tested, that is, the buffer layer ablation risk coefficient, is obtained. The buffer layer ablation risk is evaluated in this way, which can improve the accuracy of the evaluation result. In addition, the traditional method requires multiple detection items for the cable during evaluation, the process is complicated, and it is easy to cause certain damage to the cable. In actual engineering, the present invention only needs to measure the resistance value between the aluminum sheath and the buffer layer, which has little damage to the cable to be tested. Therefore, the present invention is simple to apply in actual engineering, has little damage to the sample to be tested, and has excellent economy. In addition, the evaluation method involved in the present invention only needs to detect the resistance value between the buffer layer and the aluminum sheath of the cable to be tested, which is easy to operate and has high reliability and repeatability.

[0097] Furthermore, the present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned method for evaluating the ablation risk of the buffer layer of the high-voltage corrugated aluminum sheathed cable is implemented.

[0098] Furthermore, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method for evaluating the risk of ablation of the buffer layer of a high-voltage corrugated aluminum sheathed cable is implemented.

[0099] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0100] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A method for evaluating the ablation risk of the buffer layer of a high-voltage corrugated aluminum sheathed cable, characterized in that: include: Determine the starting ablation temperature of the buffer layer of the cable to be tested; Measuring a first resistance value between the buffer layer and the aluminum sheath of the cable to be tested when the operating temperature of the buffer layer of the cable to be tested reaches the starting ablation temperature of the buffer layer; The buffer layer and the aluminum sheath of the cable to be tested are used as the positive and negative electrodes of the test respectively, a test voltage is applied, and a second resistance value between the buffer layer and the aluminum sheath of the cable to be tested is measured; The ratio of the second resistance value to the first resistance value is calculated to obtain a buffer layer ablation risk coefficient, and the magnitude relationship between the buffer layer ablation risk coefficient and a preset threshold is determined to determine whether there is ablation risk for the buffer layer of the cable to be tested.

2. The method for evaluating the ablation risk of the buffer layer of a high-voltage corrugated aluminum sheathed cable according to claim 1, characterized in that: Determine the buffer layer ablation starting temperature of the cable under test, including: Taking the buffer layer of the cable to be tested with a preset length as a test sample, and recording the surface morphology of the test sample before heating; Based on the set temperature gradient, the test piece is heated for a preset time in sequence, and after each heating is completed, the surface morphology of the test piece is compared with the surface morphology of the test piece before heating to determine the starting ablation temperature of the buffer layer of the cable to be tested.

3. The method for evaluating the ablation risk of the buffer layer of a high-voltage corrugated aluminum sheathed cable according to claim 1, characterized in that: Measuring a first resistance value between the buffer layer and the aluminum sheath of the cable to be tested when the operating temperature of the buffer layer of the cable to be tested reaches the starting ablation temperature of the buffer layer, comprising: Determine the resistivity of the buffer layer of the cable to be tested at different deformation distances; Determine the current density and temperature field of the buffer layer under different interference fit distances and different numbers of poor contact points of the cable to be tested, and determine the interference fit distance and the number of poor contact points when the operating temperature of the buffer layer reaches the starting ablation temperature of the buffer layer based on the determined current density and temperature field of the buffer layer; The first resistance value is determined based on the resistivity of the buffer layer of the cable to be tested at different deformation distances, the interference fit distance when the operating temperature of the buffer layer reaches the initial ablation temperature of the buffer layer, and the number of poor contact points.

4. The method for evaluating the ablation risk of the buffer layer of a high-voltage corrugated aluminum sheathed cable according to claim 3 is characterized in that: Determine the current density and temperature field of the buffer layer of the tested cable at different interference fit distances and different numbers of poor contact points, including: Obtaining the physical parameter values ​​of each layer of the cable to be tested, the physical parameters at least including relative dielectric constant, resistivity, thermal conductivity, constant pressure heat capacity, density and outer diameter parameters; An electrothermal coupling field simulation model of the cable to be tested is established based on the physical parameter values ​​of each layer of the cable to be tested; Obtaining the annual flow rate, ambient temperature, convection heat dissipation coefficient and voltage level parameters of the cable to be tested, so as to determine the boundary conditions of the electrothermal coupling field simulation model; The electrothermal coupling field simulation model is solved based on the boundary conditions to obtain the buffer layer current density and temperature field under different interference fit distances and different numbers of poor contact points of the cable to be tested.

5. The method for evaluating the ablation risk of the buffer layer of a high-voltage corrugated aluminum sheathed cable according to claim 3, characterized in that: Determine the resistivity of the tested cable buffer layer at different deformation distances, including: Take a buffer layer of a preset area and preset thickness as a sample; Applying pressure to the sample and recording the deformation distance of the sample; The resistance value of the sample at different deformation distances is measured to obtain the resistivity of the buffer layer of the cable to be tested at different deformation distances.

6. The method for evaluating the ablation risk of the buffer layer of a high-voltage corrugated aluminum sheathed cable according to claim 3, characterized in that: The interference fit distance is the radial distance that the aluminum sheath of the cable to be tested is pressed into the buffer layer of the cable to be tested; the number of poor contact points is the number of troughs where the aluminum sheath of the cable to be tested is not in contact with the buffer layer of the cable to be tested.

7. The method for evaluating the ablation risk of the buffer layer of a high-voltage corrugated aluminum sheathed cable according to any one of claims 1 to 6, characterized in that: Determining the magnitude relationship between the buffer layer ablation risk coefficient and a preset threshold value to determine whether the buffer layer of the cable to be tested has ablation risk includes: When the buffer layer ablation risk coefficient is greater than a preset threshold, it is determined that the buffer layer of the cable under test has ablation risk; otherwise, it is determined that the buffer layer of the cable under test has no ablation risk.

8. An evaluation system for the ablation risk of the buffer layer of a high-voltage corrugated aluminum sheathed cable, characterized in that: include: A determination module, used to determine the starting ablation temperature of the buffer layer of the cable to be tested; A first measuring module is used to measure a first resistance value between the buffer layer and the aluminum sheath of the cable to be tested when the operating temperature of the buffer layer of the cable to be tested reaches the starting ablation temperature of the buffer layer; The second measuring module is used to use the buffer layer and the aluminum sheath of the cable to be tested as the positive and negative electrodes of the test respectively, apply a test voltage, and measure a second resistance value between the buffer layer and the aluminum sheath of the cable to be tested; A calculation module, used for calculating the ratio of the second resistance value to the first resistance value to obtain a buffer layer ablation risk coefficient; A judgment module, used to judge the magnitude relationship between the buffer layer ablation risk coefficient and a preset threshold; The evaluation module is used to determine whether the buffer layer of the cable to be tested has a risk of ablation based on the size relationship judgment result.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for evaluating the risk of ablation of a buffer layer of a high-voltage corrugated aluminum sheathed cable as described in any one of claims 1 to 7 is implemented.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, it implements the method for evaluating the risk of ablation of the buffer layer of the high-voltage corrugated aluminum sheathed cable as described in any one of claims 1-7.

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