Method and device for determining compression state of buffer layer of high-voltage cable and electronic equipment

Abstract

The invention discloses a method and device for determining the compression state of a buffer layer of a high-voltage cable and electronic equipment. The method comprises the steps that a measuring device obtains a curve used for representing the relation between the resistivity and the pressure intensity of the buffer layer of the high-voltage cable; a turning interval of the curve is determined, and the turning interval comprises an interval in which the curve slope change rate of the curve is larger than a preset threshold value; determining a target turning point from the turning interval, and taking a pressure value corresponding to the target turning point as a critical pressure value; and determining the compression state of the high-voltage cable buffer layer by using the critical pressure value. The technical problems that the transition section of the resistivity-pressure curve of the buffer layer is long and smooth, whether the buffer layer of the high-voltage cable is pressed or not is judged through manual observation, errors are large, and reproducibility is lacked are solved.

Description

Technical Field

[0001] The present application relates to the field of data processing, and in particular to a method, device and electronic equipment for determining a compression state of a high-voltage cable buffer layer. Background Art

[0002] In response to the ablation defects of the high-voltage cable buffer layer, the relevant technology judges whether the high-voltage cable buffer layer is compressed by manually observing the resistivity-pressure curve of the high-voltage cable buffer layer. Since the transition section of the resistivity-pressure curve of the high-voltage cable buffer layer is long and smooth, the manual observation method will lead to large errors due to subjective factors, unreliability, and lack of reproducibility.

[0003] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0004] The embodiments of the present application provide a method, device and electronic device for determining the compression state of a high-voltage cable buffer layer, so as to at least solve the technical problem that, due to the long and smooth transition section of the resistivity-pressure curve of the buffer layer, manual observation to determine whether the buffer layer of the high-voltage cable is compressed results in large errors and lack of reproducibility.

[0005] According to one aspect of an embodiment of the present application, a method for determining a compression state of a high-voltage cable buffer layer is provided, comprising: obtaining, by a measuring device, a curve representing the relationship between the resistivity and pressure of a high-voltage cable buffer layer; determining a turning interval of the curve, wherein the turning interval includes an interval in which the rate of change of the slope of the curve is greater than a preset threshold; determining a target turning point from the turning interval, and taking the pressure value corresponding to the target turning point as a critical pressure value; and determining the compression state of the high-voltage cable buffer layer using the critical pressure value.

[0006] In some embodiments of the present application, determining the turning interval of the curve includes: obtaining the maximum pressure value of a measurement point in a measurement point set, wherein the measurement points in the measurement point set are used to represent the resistivity of a high-voltage cable buffer layer under different pressure conditions; performing a function operation on the maximum pressure value and a first preset ratio and a second preset ratio, respectively, to obtain a first pressure value and a second pressure value, wherein the first preset ratio is less than the second preset ratio; using the measurement point corresponding to the first pressure value as the first first endpoint of the turning interval, and using the measurement point corresponding to the second pressure value as the first last endpoint of the turning interval.

[0007] In some embodiments of the present application, determining a target turning point from a turning interval includes: obtaining a second first endpoint of the curve and a second last endpoint of the curve; obtaining a first turning point from the measurement points included in the turning interval, wherein the first turning point is any measurement point in the turning interval; determining a loss function value of the first turning point based on the second first endpoint of the curve, the second last endpoint of the curve, and the measurement points included in the turning interval; and determining the target turning point from the measurement points included in the turning interval based on the loss function value.

[0008] In some embodiments of the present application, the loss function value of the first turning point is determined based on the second first endpoint of the curve, the second last endpoint of the curve, and the measurement points included in the turning interval, including: linearly fitting the first turning point with the second first endpoint and the second last endpoint, respectively, to obtain the first function and the second function; obtaining the original function value of each measurement point in the turning interval on the curve, as well as the first function value corresponding to the first function and the second function value corresponding to the second function of each measurement point; and calculating the loss function value of the first turning point using the original function value, the first function value, and the second function value.

[0009] In some embodiments of the present application, after determining the target turning point from the measurement points included in the turning interval based on the loss function value, it also includes: comparing the target turning point with the endpoints of the turning interval, wherein the endpoints of the turning interval include the first endpoint of the turning interval and the first tail endpoint of the turning interval; when the target turning point is the endpoint of the turning interval, expanding the turning interval; and redetermining the target turning point using the expanded turning interval.

[0010] In some embodiments of the present application, when the target turning point is the endpoint of the turning interval, the turning interval is expanded, including: when the target turning point is the first endpoint of the turning interval, the pressure value of the first endpoint is subjected to a function operation with a third preset ratio to obtain a third pressure value, and the measurement point corresponding to the third pressure value is used as the target first endpoint of the turning interval, wherein the third pressure value is less than the pressure value of the first endpoint; when the target turning point is the first tail endpoint of the turning interval, the pressure value of the first tail endpoint is subjected to a function operation with a fourth preset ratio to obtain a fourth pressure value, and the measurement point corresponding to the fourth pressure value is used as the target tail endpoint of the turning interval, wherein the fourth pressure value is greater than the pressure value of the first tail endpoint.

[0011] In some embodiments of the present application, a compression state of a high-voltage cable buffer layer is determined using a critical pressure value, including: measuring the pressure value of the high-voltage cable buffer layer; comparing the pressure value of the high-voltage cable buffer layer with the critical pressure value; when the pressure value of the high-voltage cable buffer layer is greater than the critical pressure value, determining that the high-voltage cable buffer layer is in a compression state; when the pressure value of the high-voltage cable buffer layer is less than or equal to the critical pressure value, determining that the high-voltage cable buffer layer is in a non-compression state.

[0012] According to another aspect of the embodiment of the present application, a device for determining the compression state of a high-voltage cable buffer layer is also provided, including: an acquisition module for acquiring a curve for representing the relationship between the resistivity and pressure of the high-voltage cable buffer layer; a first determination module for determining a turning interval of the curve, wherein the turning interval includes an interval in which the rate of change of the slope of the curve is greater than a preset threshold; a second determination module for determining a target turning point from the turning interval, and taking the pressure value corresponding to the target turning point as a critical pressure value; and an execution module for determining the compression state of the high-voltage cable buffer layer using the critical pressure value.

[0013] According to another aspect of the embodiments of the present application, there is also provided an electronic device, including: a memory and a processor, the memory being used to store program instructions; the processor being connected to the memory and being used to execute the method for determining the compression state of the high-voltage cable buffer layer.

[0014] According to another aspect of the embodiment of the present application, a non-volatile storage medium is also provided, which includes a stored computer program, wherein the device where the non-volatile storage medium is located executes the above-mentioned method for determining the compression state of the high-voltage cable buffer layer by running the computer program.

[0015] According to another aspect of the embodiments of the present application, a computer program product is provided, including computer instructions, which, when executed by a processor, implement the above-mentioned method for determining the compression state of the high-voltage cable buffer layer.

[0016] In an embodiment of the present application, a measuring device determines a turning interval on a curve of the relationship between the resistivity and pressure of a high-voltage cable buffer layer, and determines a target turning point within the turning interval, and uses the pressure value of the target turning point to determine the compression state of the high-voltage cable buffer layer. By accurately determining the target turning point on the curve by the measuring device, the target turning point can be used to accurately determine whether high-voltage cables of different voltage levels and different types of buffer layers are compressed, thereby achieving the technical effect of reducing the burning failure of the high-voltage cable buffer layer and effectively improving the conductive performance of the high-voltage cable buffer layer, and further solving the technical problem of large errors and lack of reproducibility in judging whether the high-voltage cable buffer layer is compressed by manual observation due to the long and smooth transition section of the resistivity-pressure curve of the buffer layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 It is a hardware structure block diagram of a computer terminal of a method for determining a compression state of a high-voltage cable buffer layer according to an embodiment of the present application;

[0019] Figure 2 is a flow chart of a method for determining a compression state of a high-voltage cable buffer layer according to an embodiment of the present application;

[0020] Figure 3 is a schematic diagram of a curve showing the relationship between resistivity and pressure of a high-voltage cable buffer layer according to an embodiment of the present application;

[0021] Figure 4 It is a schematic diagram of the overall process of a method for determining the compression state of a high-voltage cable buffer layer according to an embodiment of the present application;

[0022] Figure 5 It is a structural schematic diagram of a device for determining the compression state of a high-voltage cable buffer layer according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] In order to better understand the embodiments of the present application, the technical terms involved in the embodiments of the present application are explained as follows:

[0026] High-voltage cable: refers to a power cable used to transmit high voltage (generally above 10kV), mainly used for long-distance power transmission.

[0027] Buffer layer: In the high-voltage cable structure, the buffer layer is usually located between the insulation layer and the metal sheath. It has semi-conductive properties and its main function is to balance the electric field inside the cable and reduce the uneven impact of the electric field on the insulation layer. It also plays a role in physical protection and water blocking.

[0028] Resistivity: A physical quantity used to measure the conductive properties of a material, which indicates the material resistance per unit length and per unit cross-sectional area. For the buffer layer of a high-voltage cable, the change in resistivity is closely related to its degree of moisture and compression state.

[0029] Pressure: Pressure refers to the pressure per unit area, a physical quantity used to measure the degree of force on an object. In high-voltage cables, the pressure of the metal sheath on the buffer layer affects the structural tightness and conductivity of the buffer layer.

[0030] 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 defects, gradually deteriorating the main insulation of the cable and eventually causing insulation breakdown. The buffer layer ablation defect has a very high latency, a very long development process, and a large range of action, which has a serious impact on the safe operation of urban power transmission networks.

[0031] The buffer layer ablation defect is caused by the change in the resistivity of the damp semi-conductive water buffer layer strip (the conductivity of the damp buffer layer is reduced, and the sodium salt generated by the chemical reaction also has a low conductivity), which leads to poor contact between the corrugated aluminum sheath and the insulating shielding layer, and local electric field distortion is generated 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. Therefore, it is extremely important to determine the conductive performance of the high-voltage cable buffer layer.

[0032] Under pressure, due to the loose and porous structure of the buffer layer, the resistivity of the buffer layer will change greatly. The test results of the buffer layer-pressure characteristic curve show that the characteristic curve is an "L" curve with an obvious smooth turning area. By determining a turning point in the smooth turning area of ​​this curve, the critical pressure value at which the resistivity of the buffer layer of different models changes from faster to slower can be accurately found. By controlling the pressure of the high-voltage cable metal sheath on the buffer layer, the resistivity of the buffer layer is controlled in the area after this turning point (i.e., the area with lower resistivity and slower change), which can effectively improve the conductivity of the buffer layer.

[0033] In the related art, there is no clear technical solution for determining whether the buffer layer of a high-voltage cable is compressed, and most of them are based on human observation. However, the transition section of the resistivity-pressure characteristic curve of the buffer layer is long and smooth, and the human observation method will lead to large errors due to subjective factors, and lack reliability and repeatability. In order to solve the above technical problems, the embodiments of the present application provide corresponding solutions, which are described in detail below.

[0034] The method for determining the compression state of the high-voltage cable buffer layer provided in the embodiment of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Figure 1 The hardware structure block diagram of a computer terminal for implementing a method for determining the compression state of a high-voltage cable buffer layer is shown. Figure 1 As shown, the computer terminal 10 may include one or more (102a, 102b, ..., 102n are used to illustrate) processors (the processor may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA), a memory 104 for storing data, and a transmission module 106 for communication functions connected via a wired and / or wireless network. In addition, it may also include: a display, a keyboard, a cursor control device, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the I / O interface), a network interface, and a BUS bus. Those skilled in the art can understand that Figure 1 The structure shown is only for illustration and does not limit the structure of the above electronic device. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.

[0035] It should be noted that the one or more processors and / or other data processing circuits described above may generally be referred to herein as "data processing circuits". The data processing circuits may be embodied in whole or in part as software, hardware, firmware, or any other combination thereof. In addition, the data processing circuit may be a single independent processing module, or may be incorporated in whole or in part into any of the other components in the computer terminal 10. As described in the embodiments of the present application, the data processing circuit acts as a processor control (e.g., selection of a variable resistor terminal path connected to an interface).

[0036] The memory 104 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the method for determining the compression state of the high-voltage cable buffer layer in the embodiment of the present application. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory 104, that is, the above-mentioned method for determining the compression state of the high-voltage cable buffer layer is realized. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor, and these remote memories may be connected to the computer terminal 10 via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0037] The transmission module 106 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of the computer terminal 10. In one example, the transmission module 106 includes a network adapter (Network Interface Controller, NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission module 106 can be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0038] The display may be, for example, a touch screen liquid crystal display (LCD) that enables a user to interact with a user interface of the computer terminal 10 .

[0039] It should be noted that, in some optional embodiments, the above Figure 1 The computer terminal shown may include hardware elements (including circuits), software elements (including computer code stored on a computer-readable medium), or a combination of hardware elements and software elements. It should be noted that Figure 1 This is merely one example of a particular embodiment and is intended to illustrate the types of components that may be present in the computer terminal described above.

[0040] Under the above-mentioned operating environment, an embodiment of the present application provides an embodiment of a method for determining the compression state of a high-voltage cable buffer layer. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0041] Figure 2 is a flow chart of a method for determining a compression state of a high-voltage cable buffer layer according to an embodiment of the present application, such as Figure 2 As shown, the method comprises the following steps:

[0042] Step S202: The measuring device obtains a curve for representing the relationship between the resistivity and pressure of the buffer layer of the high-voltage cable.

[0043] In step S202, the measuring device refers to an instrument or system capable of measuring the resistivity of the high-voltage cable buffer layer under different pressures. In some embodiments, the measuring device may include but is not limited to a pressure sensor, a resistance measuring instrument, a computer control system, etc. For example, the measuring device may be a device including a pressure chamber and a resistance measuring circuit, the pressure chamber can apply pressure through a hydraulic system or a pneumatic system, and the resistance measuring circuit can measure the resistance value of the buffer layer under different pressures, thereby calculating the resistivity.

[0044] In some embodiments, a curve showing the relationship between the resistivity and pressure of a high-voltage cable buffer layer can be obtained by the following steps: sampling the buffer layer of the high-voltage cable, performing resistivity tests on the buffer layer under different pressure conditions, obtaining a set of measurement points reflecting the resistivity-pressure relationship of the buffer layer, and performing polynomial fitting on the measurement points in the measurement point set to obtain a smooth buffer layer resistivity-pressure characteristic curve.

[0045] The relationship curve between resistivity and pressure can be visualized by the distribution of measurement points in the coordinate system. For example, using the horizontal axis to represent pressure and the vertical axis to represent resistivity can show how the resistivity of the buffer layer changes with increasing pressure.

[0046] Step S204, determining a turning interval of the curve, wherein the turning interval includes an interval in which the rate of change of the slope of the curve is greater than a preset threshold.

[0047] In step S204, the turning interval refers to the area in the resistivity-pressure relationship curve of the buffer layer where the resistivity changes from fast to slow (i.e., the area where the rate of change of resistivity to pressure changes significantly). The curve slope change rate refers to the difference between the slope of a certain point on the resistivity-pressure relationship curve of the buffer layer and the slope of an adjacent point. The rate of change of the difference can be used to quantify the degree of slope change in the turning interval. The preset threshold is a preset curve slope change rate value, which is used to distinguish the turning interval from the non-turning interval, and can be determined based on historical data, experience, or statistical analysis methods.

[0048] In some embodiments, the turning interval can be determined by the change rate of the curve slope and a preset threshold:

[0049] (1) Calculating the slope of a curve: that is, calculating the slope of the curve at each point, for example, by differentiating the curve.

[0050] (2) Calculating the slope change rate: that is, calculating the difference between the slopes of adjacent points to obtain the slope change rate. For example, the slope change rate sequence is obtained by calculating the difference of the slope sequence.

[0051] (3) Setting a preset threshold: For example, conduct multiple experiments, analyze the distribution of the slope change rate, and select a significant change point in the slope change rate distribution as the preset threshold.

[0052] (4) Comparing the slope change rate with the preset threshold: Compare the slope change rate sequence calculated in step (2) with the preset threshold, and find the points where the slope change rate is greater than the preset threshold. The set of these points defines the range of the turning interval.

[0053] (5) Determine the turning interval: The starting point and the ending point of the turning interval can be determined by the points where the continuous slope change rate is greater than the preset threshold. For example, start from the point where the last curve slope change rate is greater than the preset threshold and search to the left until the point where the slope change rate is lower than the preset threshold for the first time is found, and determine the starting point of the turning interval; start from the point where the last curve slope change rate is greater than the preset threshold and search to the right until the point where the slope change rate is lower than the preset threshold for the first time is found, and determine the ending point of the turning interval.

[0054] In order to more accurately locate the turning point of the change in the compression state of the buffer layer, the turning interval can be determined by the following steps: obtaining the maximum pressure value of the measurement points in the measurement point set, wherein the measurement points in the measurement point set are used to represent the resistivity of the high-voltage cable buffer layer under different pressure conditions; performing function operations on the maximum pressure value and the first preset ratio and the second preset ratio respectively to obtain the first pressure value and the second pressure value, wherein the first preset ratio is smaller than the second preset ratio; taking the measurement point corresponding to the first pressure value as the first end point of the turning interval, and taking the measurement point corresponding to the second pressure value as the first end point of the turning interval.

[0055] (1) Obtaining the maximum pressure value of the measurement point in the measurement point set: that is, finding the maximum pressure value that the buffer layer can withstand from all the corresponding data of the resistivity and pressure of the high-voltage cable buffer layer measured. In some embodiments, this can be achieved by sorting the data or directly searching for the maximum pressure value in the data set.

[0056] (2) Calculate the first pressure value and the second pressure value: the first preset ratio is a preset ratio (for example, 10%) used to determine the starting end of the turning interval, and its value is less than the second preset ratio, so as to determine the starting point of the turning interval; the second preset ratio is a preset ratio (for example, 30%) used to determine the ending end of the turning interval, and its value is greater than the first preset ratio, so as to determine the ending point of the turning interval. The function operation can be linear operation, exponential operation, logarithmic operation, power operation, etc.

[0057] In some embodiments, the maximum pressure value may be multiplied by a first preset ratio to obtain a first pressure value, and the maximum pressure value may be multiplied by a second preset ratio to obtain a second pressure value.

[0058] (3) Determine the first and last endpoints of the turning interval: In some embodiments, a measurement point at which the pressure is equal to the first pressure value can be found in the data set, and the point is determined as the first first endpoint of the turning interval. A measurement point at which the pressure is equal to the second pressure value can be found in the data set, and the point is determined as the first last endpoint of the turning interval.

[0059] Step S206, determining a target turning point from the turning interval, and taking the pressure value corresponding to the target turning point as a critical pressure value.

[0060] In step S206, the target turning point refers to a key point within the turning interval that can accurately reflect the transition of the buffer layer from a non-compressed state to a compressed state. The critical pressure value refers to a standard value that can be used for the manufacture, detection and maintenance of high-voltage cables. In some embodiments, when the pressure on the buffer layer of the high-voltage cable is greater than the critical pressure value, it can be considered that the buffer layer has been compressed, and when the pressure is less than or equal to the critical pressure value, the buffer layer is in a non-compressed state.

[0061] In some embodiments, the target turning point is a unique point calculated from the measurement points included in the turning interval. For example, the slope change rate of each point in the turning interval can be calculated to obtain the point with the smallest slope change rate as the target turning point, or a statistical method can be used to analyze the point set in the turning interval to find the local minimum of the slope change rate. After determining the target turning point, the critical pressure value can be obtained by reading the horizontal coordinate (pressure value) of the target turning point on the curve.

[0062] In order to locate the target turning point more accurately, the target turning point can be calculated through the loss function, specifically: obtain the second first endpoint of the curve and the second last endpoint of the curve; obtain the first turning point from the measurement points included in the turning interval, wherein the first turning point is any measurement point in the turning interval; determine the loss function value of the first turning point based on the second first endpoint of the curve, the second last endpoint of the curve and the measurement points included in the turning interval; determine the target turning point from the measurement points included in the turning interval based on the loss function value.

[0063] The second first endpoint refers to a starting point on the smooth curve obtained after curve fitting, located at the end with a lower pressure value. In some embodiments, the second first endpoint can be a point outside the measurement point set, for example, an endpoint of the curve after data processing or fitting. The second tail endpoint is opposite to the second first endpoint, refers to the end point on the smooth curve obtained after curve fitting, and is located at the end with a higher pressure value.

[0064] In some embodiments, the following steps can be used to calculate the loss function value of the first turning point: linearly fit the first turning point with the second first endpoint and the second tail endpoint respectively to obtain the first function and the second function; obtain the original function value of each measurement point on the curve within the turning interval, as well as the first function value corresponding to the first function and the second function value corresponding to the second function of each measurement point; use the original function value, the first function value and the second function value to calculate the loss function value of the first turning point.

[0065] The first function and the second function are two linear functions obtained by linearly fitting the first turning point with the second first endpoint and the second tail endpoint, respectively, and are used to describe the trend of the resistivity of the buffer layer changing with pressure before and after the turning point. The original function value is the actual measured value on the resistivity-pressure curve of the buffer layer, for example, it can be the resistivity value of the measuring point. The first function value and the second function value include the function values ​​corresponding to each measuring point before and after the first turning point on the first function and the second function. The loss function includes mean square error (MSE), root mean square error (RMSE), etc.

[0066] In order to facilitate understanding of the above process of determining the target turning point, a specific embodiment is described below. Figure 3 is a schematic diagram of a curve showing the relationship between the resistivity and pressure of a high-voltage cable buffer layer according to an embodiment of the present application, such as Figure 3 As shown, the horizontal axis represents pressure (unit: Pa), and the vertical axis represents resistivity (unit: Ω·m). The curve of the relationship between resistivity and pressure presents an "L"-shaped curve C1.

[0067] (1) Determine the turning interval (i.e., turning section): Select the point D (X l , Y l ) is taken as the first endpoint of the turning interval, and the position E (X2, Y2) where the curve pressure is 30% of the maximum value is taken as the first end endpoint of the turning interval.

[0068] (2) Obtain the first turning point: Obtain any point B(X c.i ,Y c.i ) as the first turning point.

[0069] (3) Linearly fit the first turning point to the second first endpoint and the second last endpoint respectively: c.i ,Y c.i ) and the first endpoint A(X c.1 ,Y c.1 ), the end point C (X c.end ,Y c.end ) to obtain the linear segments L1 (AB segment, i.e. the first function) and L2 (BC segment, i.e. the second function), the calculation formula is:

[0070]

[0071] Y l =[Y l.1 ][Y l.2 ] (3)

[0072] Among them, Y l.1 is the resistivity value of a point on the linear segment L1 (i.e., the first function value), X n is the deformation distance value of the original data point, Y l.2 is the resistivity value of a point on the linear segment L2 (i.e., the value of the second function), Y l is the resistivity value of a point on the linear segment.

[0073] (4) Calculate the loss function value of the first turning point: At each measurement point in the turning interval (a total of n measurement points), the function value of the measurement point and the function values ​​of the linear segments L1 and L2 are used to calculate the RMSE. The specific calculation formula is as follows:

[0074]

[0075] Among them, Y n.j It is the resistivity value of a point on the original curve (i.e. the original function value of the measuring point on the curve).

[0076] (5) Traverse the measurement points included in the turning interval and calculate the RMSE when each measurement point is used as a turning point.

[0077] (6) Determine the target turning point from the measurement points included in the turning interval according to the loss function value: In some embodiments, the turning point corresponding to the minimum RMSE value (X c.i ,Y c.i ) as the target turning point.

[0078] (7) The pressure value in the corresponding coordinate value of the target turning point is taken as the critical pressure value.

[0079] After determining the target turning point from the measurement points included in the turning interval based on the loss function value, the following steps can also be performed: comparing the target turning point with the endpoints of the turning interval, wherein the endpoints of the turning interval include the first endpoint of the turning interval and the first tail endpoint of the turning interval; when the target turning point is the endpoint of the turning interval, expanding the turning interval; and redetermining the target turning point using the expanded turning interval.

[0080] In some embodiments, the coordinate value of the target turning point may be compared with the coordinate value of the endpoint of the turning interval to determine whether the target turning point is the endpoint of the turning interval.

[0081] When the target turning point is the endpoint of the turning interval, the turning interval can be expanded in the following manner: when the target turning point is the first endpoint of the turning interval, the pressure value of the first endpoint is subjected to a function operation with the third preset ratio to obtain a third pressure value, and the measurement point corresponding to the third pressure value is used as the target first endpoint of the turning interval, wherein the third pressure value is less than the pressure value of the first endpoint; when the target turning point is the first tail endpoint of the turning interval, the pressure value of the first tail endpoint is subjected to a function operation with the fourth preset ratio to obtain a fourth pressure value, and the measurement point corresponding to the fourth pressure value is used as the target tail endpoint of the turning interval, wherein the fourth pressure value is greater than the pressure value of the first tail endpoint.

[0082] In order to save computing resources, in some embodiments, the third preset ratio and the fourth preset ratio may be the same, and the function operation includes exponential operation, logarithmic operation, power operation, etc. The third pressure value is used to extend the first end point of the turning interval on the curve according to a preset direction, and the fourth pressure value is used to extend the first end point of the turning interval on the curve according to a preset direction, and the preset direction is the direction of expanding the turning interval. In the case where the target turning point is the first end point of the turning interval, only the first end point may be extended, or both the first end point and the first end point may be extended. In the case where the target turning point is the first end point of the turning interval, only the first end point may be extended, or both the first end point and the first end point may be extended.

[0083] In some embodiments, if the target turning point falls at the first endpoint, the maximum pressure can be reduced by 2% (i.e., the third preset ratio) based on the original pressure value of the first endpoint; if the target turning point falls at the first tail endpoint, the maximum pressure can be increased by 2% (i.e., the fourth preset ratio) based on the original pressure value of the first tail endpoint.

[0084] Take the expanded turning interval as the turning interval, re-determine the measurement points contained in the turning interval, repeat the above steps of determining the target turning point until the target turning point does not fall into the endpoint of the turning interval, and take the pressure value in the corresponding coordinate value of the target turning point as the critical pressure value.

[0085] Step S208: determining the compression state of the high-voltage cable buffer layer using the critical pressure value.

[0086] In step S208, the compression state refers to that the resistivity of the buffer layer of the high-voltage cable is stable within a preset range. When the buffer layer is in the compression state, the buffer layer material is fully compressed and the pores are reduced, which can effectively prevent electric field distortion and local overheating.

[0087] In some embodiments, the measured actual pressure value can be compared with the critical pressure value determined in step S206, specifically: measuring the pressure value of the high-voltage cable buffer layer; comparing the pressure value of the high-voltage cable buffer layer with the critical pressure value; when the pressure value of the high-voltage cable buffer layer is greater than the critical pressure value, determining that the high-voltage cable buffer layer is in a compressed state; when the pressure value of the high-voltage cable buffer layer is less than the critical pressure value, determining that the high-voltage cable buffer layer is in a non-compressed state. For example, if the pressure of the buffer layer of the high-voltage cable is measured to be 150kPa, and the critical pressure value is 120kPa, then it can be determined that the buffer layer is in a compressed state.

[0088] Through the above steps S202 to S208, the measuring equipment determines the turning interval from the curve of the relationship between the resistivity and pressure of the high-voltage cable buffer layer, and determines the target turning point from the turning interval, and uses the pressure value of the target turning point to determine the compression state of the high-voltage cable buffer layer. By accurately determining the target turning point on the curve by the measuring equipment, the purpose of using the target turning point to accurately judge whether high-voltage cables of different voltage levels and different types of buffer layers are compressed is achieved, thereby achieving the technical effect of reducing the burning failure of the high-voltage cable buffer layer and effectively improving the conductive performance of the high-voltage cable buffer layer, and further solving the technical problem of large error and lack of reproducibility in judging whether the high-voltage cable buffer layer is compressed by manual observation due to the long and smooth transition section of the resistivity-pressure curve of the buffer layer.

[0089] Figure 4 is a schematic diagram of the overall process of a method for determining the compression state of a high-voltage cable buffer layer according to an embodiment of the present application, such as Figure 4 As shown, it includes the following steps:

[0090] S402, test the resistivity-pressure characteristic curve of the buffer layer of the test cable: sample the buffer layer of the high-voltage cable. The sample needs to be representative and consistent. Under a series of preset pressure conditions, measure the resistivity of the buffer layer and record the corresponding values ​​of each set of pressure and resistivity to form an original data set.

[0091] S404, fitting the data to obtain a characteristic curve: using polynomial fitting or other curve fitting methods, the original data points are connected into a smooth curve, that is, the buffer layer resistivity-pressure characteristic curve C1.

[0092] S406, select the turning segment (ie, turning interval): according to the shape of the curve, select the area where the pressure value is between 10% and 30% of the maximum value of the curve as the turning segment S2, which is the area where the resistivity change rate begins to change significantly.

[0093] S408, assuming turning points to calculate linear segment data: within turning segment S2, cyclically select each point as a turning point, connect it with the first and last endpoints of the curve to form linear segments L1 and L2, and calculate the resistivity value of each point on L1 and L2.

[0094] S410, RMSE calculation is performed on the linear segment data and the original data: at each measurement point in the turning interval (a total of n measurement points), RMSE calculation is performed on the function value of the measurement point and the function values ​​of the linear segments L1 and L2.

[0095] S412, obtain the point on the fitting curve corresponding to the minimum RMSE: traverse all points in the turning segment S2 and find the turning point (X c.i ,Y c.i ), which is the target turning point. After obtaining the target turning point, compare it with the turning segment endpoint to confirm whether the target turning point falls within the turning segment endpoint. If so, execute step S414, otherwise execute step S416.

[0096] S414, expand the turning segment: If the assumed turning point happens to fall on the endpoint of the turning segment S2, it means that the point is not the optimal turning point. The range of the turning segment can be adjusted according to the preset rules and the target turning point can be re-determined (i.e., repeat steps S410 and S412 until the target turning point no longer falls on the endpoint of the turning segment).

[0097] S416, output the horizontal coordinate of the turning point as the critical pressure value P t : In some embodiments, the critical pressure value P t This is the horizontal coordinate of the target turning point, which indicates the critical pressure value at which the buffer layer changes from a non-compressed state to a compressed state.

[0098] S418, test the pressure P of the buffer layer of the cable to be tested: measure the pressure P of the actual high-voltage cable buffer layer during production, testing or operation, and determine whether P is greater than P t .

[0099] S420: In some embodiments, if the actual measured pressure P is greater than the critical pressure value P t , indicating that the buffer layer is in a compressed state, which helps to maintain good conductivity and prevent ablation.

[0100] S422, if the actual measured pressure P is less than or equal to the critical pressure value P t , it means that the buffer layer is not sufficiently compacted and there is a risk of insulation degradation.

[0101] Figure 5 is a structural diagram of a device for determining a compression state of a high-voltage cable buffer layer according to an embodiment of the present application, such as Figure 5 As shown, the device comprises:

[0102] An acquisition module 50, used to acquire a curve representing the relationship between the resistivity and pressure of the buffer layer of the high-voltage cable;

[0103] A first determination module 52 is used to determine a turning interval of the curve, wherein the turning interval includes an interval in which a rate of change of the curve slope of the curve is greater than a preset threshold;

[0104] A second determination module 54 is used to determine a target turning point from the turning interval, and use a pressure value corresponding to the target turning point as a critical pressure value;

[0105] The execution module 56 is used to determine the compression state of the high-voltage cable buffer layer using the critical pressure value.

[0106] In the above-mentioned device for determining the compression state of the high-voltage cable buffer layer, the first determination module is also used to obtain the maximum pressure value of the measurement points in the measurement point set, wherein the measurement points in the measurement point set are used to represent the resistivity of the high-voltage cable buffer layer under different pressure conditions; the maximum pressure value is respectively subjected to a function operation with the first preset ratio and the second preset ratio to obtain a first pressure value and a second pressure value, wherein the first preset ratio is smaller than the second preset ratio; the measurement point corresponding to the first pressure value is used as the first first endpoint of the turning interval, and the measurement point corresponding to the second pressure value is used as the first last endpoint of the turning interval.

[0107] In the above-mentioned device for determining the compression state of the high-voltage cable buffer layer, the second determination module is also used to obtain the second first endpoint of the curve and the second last endpoint of the curve; obtain the first turning point from the measurement points included in the turning interval, wherein the first turning point is any measurement point in the turning interval; determine the loss function value of the first turning point based on the second first endpoint of the curve, the second last endpoint of the curve and the measurement points included in the turning interval; determine the target turning point from the measurement points included in the turning interval based on the loss function value.

[0108] In the above-mentioned device for determining the compression state of the high-voltage cable buffer layer, the second determination module is also used to linearly fit the first turning point with the second first endpoint and the second tail endpoint respectively to obtain the first function and the second function; obtain the original function value of each measuring point in the turning interval on the curve, as well as the first function value corresponding to the first function and the second function value corresponding to the second function of each measuring point; use the original function value, the first function value and the second function value to calculate the loss function value of the first turning point.

[0109] In the above-mentioned device for determining the compression state of the high-voltage cable buffer layer, the second determination module is also used to compare the target turning point with the endpoints of the turning interval, wherein the endpoints of the turning interval include the first end point of the turning interval and the first end point of the turning interval; when the target turning point is the endpoint of the turning interval, the turning interval is expanded; and the target turning point is re-determined using the expanded turning interval.

[0110] In the above-mentioned device for determining the compression state of the high-voltage cable buffer layer, the second determination module is also used to, when the target turning point is the first end point of the turning interval, perform a function operation on the pressure value of the first end point and the third preset ratio to obtain a third pressure value, and use the measurement point corresponding to the third pressure value as the target first end point of the turning interval, wherein the third pressure value is smaller than the pressure value of the first end point; when the target turning point is the first tail end point of the turning interval, perform a function operation on the pressure value of the first tail end point and the fourth preset ratio to obtain a fourth pressure value, and use the measurement point corresponding to the fourth pressure value as the target tail end point of the turning interval, wherein the fourth pressure value is greater than the pressure value of the first tail end point.

[0111] In the above-mentioned device for determining the compression state of the high-voltage cable buffer layer, the execution module is also used to measure the pressure value of the high-voltage cable buffer layer; compare the pressure value of the high-voltage cable buffer layer with the critical pressure value; when the pressure value of the high-voltage cable buffer layer is greater than the critical pressure value, determine that the high-voltage cable buffer layer is in a compression state; when the pressure value of the high-voltage cable buffer layer is less than or equal to the critical pressure value, determine that the high-voltage cable buffer layer is in a non-compression state.

[0112] It should be noted that Figure 5The device for determining the compression state of the high-voltage cable buffer layer is used to perform Figure 2 The method for determining the compression state of the high-voltage cable buffer layer shown in FIG. Figure 2 The relevant explanations in the method for determining the compression state of the high-voltage cable buffer layer in Figure 5 The device for determining the compression state of the high-voltage cable buffer layer shown will not be described in detail here.

[0113] An embodiment of the present application also provides an electronic device, which includes a memory and a processor, wherein the memory is used to store program instructions; the processor is connected to the memory and is used to execute the steps of the method for determining the compression state of the high-voltage cable buffer layer in each embodiment of the present application.

[0114] For example, the processor performs the following functions by executing program instructions stored in the memory:

[0115] The measuring device obtains a curve representing the relationship between the resistivity and pressure of a high-voltage cable buffer layer; determines a turning interval of the curve, wherein the turning interval includes an interval in which the rate of change of the slope of the curve is greater than a preset threshold; determines a target turning point from the turning interval, and uses the pressure value corresponding to the target turning point as a critical pressure value; and uses the critical pressure value to determine the compression state of the high-voltage cable buffer layer.

[0116] An embodiment of the present application also provides a non-volatile storage medium, which includes a stored computer program, wherein the device where the non-volatile storage medium is located executes the steps of the method for determining the compression state of the high-voltage cable buffer layer in each embodiment of the present application by running the computer program.

[0117] An embodiment of the present application further provides a computer program product, including computer instructions, which, when executed by a processor, implement the steps of the method for determining the compression state of the high-voltage cable buffer layer in each embodiment of the present application.

[0118] An embodiment of the present application further provides a computer program, which, when executed by a processor, implements the steps of the method for determining the compression state of the high-voltage cable buffer layer in each embodiment of the present application.

[0119] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0120] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0121] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0122] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0123] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0124] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0125] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for determining the compression state of a high-voltage cable buffer layer, characterized in that: include: The measuring device obtains a curve for representing the relationship between the resistivity and pressure of the buffer layer of the high voltage cable; Determining a turning interval of the curve, wherein the turning interval includes an interval in which a rate of change of a curve slope of the curve is greater than a preset threshold; Determining a target turning point from the turning interval, and taking a pressure value corresponding to the target turning point as a critical pressure value; The critical pressure value is used to determine the compression state of the high-voltage cable buffer layer.

2. The method according to claim 1, characterized in that Determining the turning interval of the curve includes: Obtaining a maximum pressure value of a measurement point in a measurement point set, wherein the measurement point in the measurement point set is used to represent the resistivity of the high-voltage cable buffer layer under different pressure conditions; Performing a function operation on the maximum pressure value, a first preset ratio and a second preset ratio respectively to obtain a first pressure value and a second pressure value, wherein the first preset ratio is smaller than the second preset ratio; The measurement point corresponding to the first pressure value is used as the first first endpoint of the turning interval, and the measurement point corresponding to the second pressure value is used as the first last endpoint of the turning interval.

3. The method according to claim 1, characterized in that Determining a target turning point from the turning interval includes: Obtaining a second first endpoint of the curve and a second last endpoint of the curve; Acquire a first turning point from the measurement points included in the turning interval, wherein the first turning point is any measurement point in the turning interval; Determine the loss function value of the first turning point according to the second first endpoint of the curve, the second last endpoint of the curve, and the measurement points included in the turning interval; The target turning point is determined from the measurement points included in the turning interval according to the loss function value.

4. The method according to claim 3, characterized in that Determining the loss function value of the first turning point according to the second first endpoint of the curve, the second tail endpoint of the curve, and the measurement points included in the turning interval includes: Performing linear fitting on the first turning point, the second first endpoint and the second tail endpoint respectively to obtain a first function and a second function; Obtaining an original function value of each measuring point within the turning interval on the curve, and a first function value corresponding to the first function and a second function value corresponding to the second function of each measuring point; The loss function value of the first turning point is calculated using the original function value, the first function value, and the second function value.

5. The method according to claim 3, characterized in that: After determining the target turning point from the measurement points included in the turning interval according to the loss function value, the method further includes: Comparing the target turning point with the endpoints of the turning interval, wherein the endpoints of the turning interval include a first end point of the turning interval and a first end point of the turning interval; When the target turning point is an end point of the turning interval, expanding the turning interval; The target turning point is re-determined using the expanded turning range.

6. The method according to claim 5, characterized in that When the target turning point is an end point of the turning interval, expanding the turning interval includes: In the case where the target turning point is the first endpoint of the turning interval, a pressure value of the first endpoint is subjected to a function operation with a third preset ratio to obtain a third pressure value, and a measurement point corresponding to the third pressure value is used as the target first endpoint of the turning interval, wherein the third pressure value is less than the pressure value of the first endpoint; When the target turning point is the first tail endpoint of the turning interval, a function operation is performed on the pressure value of the first tail endpoint and the fourth preset ratio to obtain a fourth pressure value, and the measurement point corresponding to the fourth pressure value is used as the target tail endpoint of the turning interval, wherein the fourth pressure value is greater than the pressure value of the first tail endpoint.

7. The method according to claim 1, characterized in that Determining the compression state of the high-voltage cable buffer layer by using the critical pressure value includes: Measuring the pressure value of the high-voltage cable buffer layer; Comparing the pressure value of the high-voltage cable buffer layer with the critical pressure value; When the pressure value of the high-voltage cable buffer layer is greater than the critical pressure value, determining that the high-voltage cable buffer layer is in a compressed state; When the pressure value of the high-voltage cable buffer layer is less than or equal to the critical pressure value, it is determined that the high-voltage cable buffer layer is in a non-compressed state.

8. A device for determining the compression state of a high-voltage cable buffer layer, applied to a measuring device, comprising: An acquisition module, used for acquiring a curve for representing the relationship between the resistivity and pressure of a buffer layer of a high-voltage cable; A first determination module is used to determine a turning interval of the curve, wherein the turning interval includes an interval in which a rate of change of a curve slope of the curve is greater than a preset threshold; A second determination module is used to determine a target turning point from the turning interval, and use a pressure value corresponding to the target turning point as a critical pressure value; An execution module is used to determine the compression state of the high-voltage cable buffer layer using the critical pressure value.

9. An electronic device, characterized in that: include: A memory and a processor, wherein the memory is used to store program instructions; the processor is connected to the memory and is used to execute the method for determining the compression state of the high-voltage cable buffer layer as described in any one of claims 1 to 7.

10. A non-volatile storage medium, characterized in that: The non-volatile storage medium includes a stored computer program, wherein the device where the non-volatile storage medium is located executes the method for determining the compression state of the high-voltage cable buffer layer according to any one of claims 1 to 7 by running the computer program.

11. A computer program product comprising computer instructions, characterized in that: When the computer instructions are executed by the processor, the method for determining the compression state of the high-voltage cable buffer layer according to any one of claims 1 to 7 is implemented.

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