White-spot detection method and apparatus for high-voltage cable, and electronic device and storage medium

Abstract

A white-spot detection method and apparatus for a high-voltage cable, and an electronic device and a storage medium. The method comprises: on the basis of structural parameters of each layer of external structure of a cable, establishing a circular thermal circuit model of the cable, wherein the circular thermal circuit model represents the cross section of the cable, the cross section is divided into a plurality of sector micro-elements, each sector micro-element comprises a plurality of thermal resistance branches extending from a conductor to an outer sheath, each thermal resistance branch comprises structural thermal resistances corresponding to external structures on a one-to-one basis, and at least one thermal resistance branch further comprises a white-spot thermal resistance; for each thermal resistance branch, on the basis of the radian of a sector micro-element to which the thermal resistance branch belongs, and the structural parameters, calculating thermal resistance values of structural thermal resistances on the thermal resistance branch; measuring a cable surface temperature corresponding to each thermal resistance branch, a conductor temperature, and a load current value of the conductor; and on the basis of the data, calculating a thermal resistance value of the white-spot thermal resistance, and determining whether there is a white spot and determining the position of the white spot.

Description

Methods, devices, electronic equipment and storage media for detecting white spots on high-voltage cables

[0001] This application claims priority to Chinese Patent Application No. 202411768332.4, filed with the Chinese Patent Office on December 4, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of power grid maintenance technology, such as a method, apparatus, electronic device, and storage medium for detecting white spots on high-voltage cables. Background Technology

[0003] High-voltage cross-linked polyethylene (XLPE) cables have strong current-carrying capacity, good stability, and wide application. However, with the increase in the operating time of high-voltage cables, buffer layer ablation failure may occur. This failure occurs between the corrugated aluminum sheath of the high-voltage cable body and the outer semiconductive shield (insulation layer), characterized by the formation of "white spots" on the buffer layer, the outer semiconductive shield layer, and the inner surface of the aluminum sheath. To solve the problem of white spots forming in the buffer layer after a certain period of operation in corrugated aluminum sheathed cables, cable manufacturers began to adopt a manufacturing scheme that uses smooth aluminum sheaths instead of corrugated aluminum sheaths and put it into operation. However, even with smooth aluminum sheaths, improper degassing operations or insufficient degassing time by cable manufacturers can still lead to the generation of moisture. Combined with the unavoidable potential difference, electrochemical corrosion of the buffer layer can still occur, resulting in white spots. As the cable's operating time increases, the thickness of the white spots will continuously change due to the influence of temperature, humidity, and other factors in the laying environment, thus significantly affecting the cable's operating performance.

[0004] Currently, the main method for detecting white spots is through fault inspection (white spots causing cable line faults). However, this can cause power outages and is usually only implemented after the white spot fault has significantly impacted the stable operation of the cable. There is no specific research to detect the presence of white spots in normally operating cables. Furthermore, most research focuses on white spot repair methods and post-repair discharge performance testing, without providing a method for determining the location of white spots. Summary of the Invention

[0005] This application provides a method for detecting white spots on high-voltage cables to solve the problem of detecting white spots on high-voltage cables.

[0006] In a first aspect, this application provides a method for detecting white spots on high-voltage cables. The cable structure includes a conductor and a three-layer external structure. The external structure, from the inside out, includes an insulation layer, a buffer layer, and an outer sheath. The cross-section of the external structure is annular. The method includes:

[0007] Obtain the structural parameters of the external structure of each layer of the cable, including the inner and outer diameters of the external structure;

[0008] A circular thermal circuit model of the cable is established based on the structural parameters. The circular thermal circuit model is the cross-section of the cable. The cross-section is divided into multiple sector-shaped micro-elements. Each sector-shaped micro-element includes multiple thermal resistance branches extending from the conductor to the outer sheath. Each thermal resistance branch includes a structural thermal resistance that corresponds one-to-one with the external structure. At least one thermal resistance branch also includes white spot thermal resistance.

[0009] For each thermal resistance branch, the thermal resistance value of the structural thermal resistance on each thermal resistance branch is calculated based on the radii of the corresponding sector micro-element and the structural parameters.

[0010] Measure the cable surface temperature, conductor temperature, and conductor load current value corresponding to each thermal resistance branch;

[0011] Calculate the total heat flow of the cable based on the conductor temperature and the load current value;

[0012] The thermal resistance of the white spot is calculated based on the thermal resistance value of the structure, the surface temperature of the cable, the conductor temperature, and the total heat flow of the cable.

[0013] The presence and location of white spots are determined based on the thermal resistance value of the white spot thermal resistance.

[0014] Secondly, this application provides a high-voltage cable white spot detection device. The cable structure includes a conductor and a three-layer external structure. The external structure, from the inside out, includes an insulation layer, a buffer layer, and an outer sheath. The cross-section of the external structure is annular. The device includes:

[0015] The structural parameter acquisition module is used to acquire the structural parameters of the external structure of each layer of the cable, including the inner diameter and outer diameter of the external structure.

[0016] A thermal circuit model construction module is used to establish a circular thermal circuit model of the cable based on the structural parameters. The circular thermal circuit model is the cross-section of the cable, which is divided into multiple sector-shaped micro-elements. Each sector-shaped micro-element includes multiple thermal resistance branches extending from the conductor to the outer sheath. Each thermal resistance branch includes a structural thermal resistance that corresponds one-to-one with the external structure. At least one thermal resistance branch also includes white spot thermal resistance.

[0017] The thermal resistance calculation module is used to calculate the thermal resistance value of the structural thermal resistance on each thermal resistance branch based on the radius of the sector micro-element to which it belongs and the structural parameters.

[0018] The parameter measurement module is used to measure the cable surface temperature, conductor temperature, and conductor load current value corresponding to each thermal resistance branch.

[0019] The cable heat flow calculation module is used to calculate the total heat flow of the cable based on the conductor temperature and the load current value.

[0020] The white spot thermal resistance calculation module is used to calculate the thermal resistance value of the white spot based on the thermal resistance value of the structure, the surface temperature of the cable, the conductor temperature, and the total heat flow of the cable.

[0021] The white spot qualitative module is used to determine whether a white spot exists and its location when it exists, based on the thermal resistance value of the white spot thermal resistance.

[0022] Thirdly, this application provides an electronic device, the electronic device comprising:

[0023] At least one processor; and

[0024] A memory communicatively connected to the at least one processor; wherein,

[0025] The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the high-voltage cable white spot detection method described in the first aspect of this application.

[0026] Fourthly, this application provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the high-voltage cable white spot detection method described in the first aspect of this application.

[0027] The high-voltage cable white spot detection method provided in this application first obtains the structural parameters of the external structure of each layer of the cable, including the inner and outer diameters of the external structure; based on the structural parameters, a circular thermal circuit model of the cable is established, which is the cross-section of the cable. The cross-section is divided into multiple sector-shaped micro-elements, each sector-shaped micro-element including multiple thermal resistance branches extending from the conductor to the outer sheath, and each thermal resistance branch including a structural thermal resistance corresponding to the external structure; at least one thermal resistance branch also includes white spot thermal resistance; for each thermal resistance branch, the thermal resistance value of the structural thermal resistance on each thermal resistance branch is calculated based on the arc of the sector-shaped micro-element and the structural parameters; the cable surface temperature, conductor temperature, and conductor load current value corresponding to each thermal resistance branch are measured; the total heat flow of the cable is calculated based on the conductor temperature and load current value; the thermal resistance value of the white spot thermal resistance is calculated based on the thermal resistance value of the structural thermal resistance, cable surface temperature, conductor temperature, and total heat flow of the cable; and the presence and location of white spots are determined based on the thermal resistance value of the white spot thermal resistance. By virtually constructing the sector-shaped micro-element containing the white spot based on the thermal circuit model, and by measuring and calculating the parameters in each sector-shaped micro-element, and qualitatively calculating the thermal resistance value of the white spot according to Fourier's heat transfer law and the thermal circuit model, it is possible to determine whether the white spot exists and its location when it exists. This allows for the detection of white spots in their early stages, guiding the timely repair of the cable with filling and repair fluid, and preventing the white spot from expanding further and causing a significant impact on the cable's operating performance. Attached Figure Description

[0028] Figure 1 is a schematic diagram of the cross-sectional structure of a cable provided in an embodiment of this application;

[0029] Figure 2 is a flowchart of a method for detecting white spots on high-voltage cables provided in an embodiment of this application;

[0030] Figure 3 is a schematic diagram of a circular thermal path model provided in an embodiment of this application;

[0031] Figure 4 is a structural schematic diagram of a high-voltage cable white spot detection device provided in an embodiment of this application;

[0032] Figure 5 is a schematic diagram of the structure of the electronic device provided in an embodiment of this application. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0034] This application provides a method for detecting white spots on high-voltage cables. This embodiment is applicable to detecting white spots on the insulation layer of high-voltage cables. The method can be executed by a high-voltage cable white spot detection device, which can be implemented in hardware and / or software and can be configured in electronic equipment. The cable in this application is a high-voltage cable.

[0035] Figure 1 is a schematic diagram of the cross-sectional structure of a cable provided in an embodiment of this application. As shown in Figure 1, the cable structure includes a conductor A0 and three outer structures. The outer structures, from the inside out, include an insulation layer A1, a buffer layer A2, and an outer sheath A2. The cross-section of the outer structure is annular, and the cross-section of the conductor A1 is circular.

[0036] Figure 2 is a flowchart of a method for detecting white spots on high-voltage cables according to an embodiment of this application. As shown in Figure 2, the method for detecting white spots on high-voltage cables includes:

[0037] S201. Obtain the structural parameters of the external structure of each layer of the cable.

[0038] Structural parameters include the inner and outer diameters of the external structure. Additionally, they include thermal conductivity, among other parameters.

[0039] S202. Establish a circular thermal circuit model of the cable based on the structural parameters.

[0040] The circular thermal circuit model represents the cross-section of the cable, which is divided into multiple sector-shaped micro-elements. Each sector-shaped micro-element includes multiple thermal resistance branches extending from the conductor to the outer sheath. Each thermal resistance branch includes structural thermal resistance corresponding to the external structure; at least one thermal resistance branch also includes white spot thermal resistance.

[0041] Figure 3 is a schematic diagram of a circular thermal circuit model. In an optional example, as shown in Figure 3, the circular thermal circuit model is the cross-section of the cable, consisting of a circle and three annular rings from the inside out. From the inside out, these rings represent the conductor A0, insulation layer A1, buffer layer A2, and outer sheath A2. The cross-section is divided into multiple sector-shaped micro-elements. In this example, there are four sector-shaped micro-elements, each with the same radian (π / 2). Each of the four thermal resistance branches includes three structural thermal resistances corresponding to the insulation layer A1, buffer layer A2, and outer sheath A2. One of the thermal resistance branches also includes a white spot thermal resistance To. In this example, the outer sheath A2 is a smooth aluminum sheath.

[0042] In an optional example, as shown in Figure 3, there are four sector-shaped micro-elements, each with an radian θ of π / 2. The thermal resistance branch corresponding to the first sector-shaped micro-element includes the structural thermal resistance T. 11 T 12 T 13The thermal resistance branch corresponding to the second sector element includes the structural thermal resistance T. 21 T 22 T 23 The thermal resistance branch corresponding to the third sector element includes the structural thermal resistance T. 31 T 32 T 33 The thermal resistance branch corresponding to the fourth sector element includes the structural thermal resistance T. 41 T 42 T 43 It also includes the white spot thermal resistance To; the white spot thermal resistance To is a preset virtual thermal resistance, that is, it is assumed that there is a white spot at this position and the white spot thermal resistance is To.

[0043] S203. For each thermal resistance branch, calculate the thermal resistance value of the structural thermal resistance on each thermal resistance branch based on the radii and structural parameters of the corresponding sector micro-element.

[0044] Specifically, the formula for calculating the thermal resistance value of the structure on each of the aforementioned thermal resistance branches is as follows:

[0045] Where i is the index of the sector element to which the thermal resistance branch belongs, i = 1, 2…N s N s The number of the sector-shaped micro-elements; j is the number of layers of the external structure in the sector-shaped micro-elements, j = 1, 2…3, λ i Let r be the thermal conductivity, θ be the radian of the sector-shaped micro-element, and r be the thermal conductivity. jw Let r be the outer diameter of the external structure of the j-th layer. jn Let T be the inner diameter of the external structure of the j-th layer. ij The thermal resistance value is the value of the structural thermal resistance corresponding to the external structure of the j-th layer in the i-th sector micro-element.

[0046] In an optional example, as shown in Figure 3, there are 4 sector elements, and the radian θ of each sector element is π / 2.

[0047] S204. Measure the cable surface temperature, conductor temperature, and conductor load current value corresponding to each thermal resistance branch.

[0048] In an optional embodiment, the temperature (cable surface temperature, conductor temperature) is measured using a temperature sensor. Before measuring the cable surface temperature, conductor temperature, and conductor load current value corresponding to each of the thermal resistance branches, the method further includes: acquiring the temperature sensor reading deviation; determining whether the temperature sensor reading deviation is less than a preset deviation range; if so, then performing the step of measuring the cable surface temperature, conductor temperature, and conductor load current value corresponding to each of the thermal resistance branches. To ensure the accuracy of the temperature sensor measurement data, before using the sensor, the temperature sensor is connected to the same experimental instrument to observe whether there is a deviation in the reading and the specific reading deviation. Temperature sensors with large deviations are replaced promptly to reduce detection errors.

[0049] Specifically, the surface temperatures of the cables corresponding to the four thermal resistance branches can be directly measured. In the circular thermal circuit model shown in Figure 3, the surface temperatures of the four thermal resistance branches are measured as θ1, θ2, θ3, and θ4, respectively. The conductor temperature needs to be measured by drilling along the trough of the aluminum sheath to the conductor and using a temperature sensor to detect the conductor temperature θ. c The load current value of the conductor can be measured by contact with a current sensor.

[0050] S205. Calculate the total heat flow of the cable based on the conductor temperature and load current value.

[0051] The formula for calculating the total heat flux of the cable is as follows: Q = I 2 R; R = R0[1 + α] 20 (θ c -20)][1+y s +y p ];

[0052] Where Q is the total heat flux of the cable, I is the load current, R is the AC resistance of the conductor, and R0, α 20 Let θ be the DC resistance and temperature coefficient of the conductor at 20℃. c For the temperature of the conductor, y s y p These are known skin effect factors and proximity effect factors.

[0053] The standard soft copper temperature coefficient is 0.00392K. The cable in this application is a single-core cable, that is, the number of conductors is 1. For a single-core cable, the proximity effect factor is 0.

[0054] S206. Calculate the thermal resistance of the white spot based on the thermal resistance of the structure, the surface temperature of the cable, the conductor temperature, and the heat flow of the entire cable.

[0055] Specifically, the thermal resistance value of the white spot is calculated based on the thermal resistance value of the structure, the surface temperature of the cable, the conductor temperature, and the total heat flow of the cable, including:

[0056] Based on Fourier's heat transfer law and the circular thermal path model, a linear matrix formula is constructed. The linear matrix formula includes the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, the total heat flux of the cable, and the white spot thermal resistance. The thermal resistance value of the white spot thermal resistance is obtained by substituting the values ​​of the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, and the total heat flux of the cable into the linear matrix formula.

[0057] Fourier's law of heat transfer, also known as Fourier's law, describes that in the process of heat conduction, the amount of heat passing through a given cross section per unit time is directly proportional to the rate of temperature change and the cross section area in the direction perpendicular to that cross section, and the direction of heat transfer is opposite to the direction of temperature increase.

[0058] In an optional embodiment, in the circular thermal path model shown in Figure 3, the white spot thermal resistance is set on the fourth thermal resistance branch, and the established linear matrix formula is:

[0059] Where i is the index of the sector element to which the thermal resistance branch belongs, i = 1, 2…N s N s The number of the sector-shaped micro-elements; j is the number of layers of the external structure in the sector-shaped micro-elements, j = 1, 2, 3, λ i Let r be the thermal conductivity, θ be the radian of the sector-shaped micro-element, and r be the thermal conductivity. jw Let r be the outer diameter of the external structure of the j-th layer. jn Let T be the inner diameter of the external structure of the j-th layer. ij T0 is the thermal resistance value of the external structure corresponding to the j-th layer in the i-th sector micro-element, and T0 is the thermal resistance value of the white spot thermal resistance.

[0060] Of course, the white spot thermal resistance can also be set on other thermal resistance branches. In an optional embodiment, the white spot thermal resistance is set on the third thermal resistance branch. In the circular thermal circuit model shown in Figure 3, the established linear matrix formula is:

[0061] In another optional embodiment, if the number of sector-shaped micro-elements is 5, the radian of each sector-shaped micro-element is 2π / 5, and the white spot thermal resistance is set on the 3rd and 5th thermal resistance branches, based on the process of constructing the circular thermal path model and the linear matrix formula described above, the established linear matrix formula can be derived as follows:

[0062] In an optional embodiment, the formula for calculating the total heat flux of the cable is as follows: R = R0[1 + α] 20 (θ c -20)][1+y s +y p ];

[0063] Where Q is the total heat flux of the cable, and I l R is the current carrying capacity of the conductor, R is the AC resistance of the conductor, and R0 and α are also mentioned. 20 Let θ be the DC resistance and temperature coefficient of the conductor at 20℃. c For the temperature of the conductor, y s y p These are known skin effect factors and proximity effect factors.

[0064] Among them, the carrying capacity I l Let θ be the maximum current that a conductor can continuously and stably carry at 90℃, and the conductor temperature at this point be θ. c The temperature is 90℃. Therefore, in this embodiment, the conductor temperature θ can be directly obtained. c This eliminates the need to drill through the cable surface to the conductor surface to detect conductor temperature, thus enabling non-destructive testing of white spot thermal resistance.

[0065] The standard temperature coefficient of soft copper is 0.00392K. The cable in this application is a single-core cable, that is, the number of conductors is 1. For a single-core cable, the proximity effect factor is 0.

[0066] S207. Determine whether white spots exist and their location when they do exist based on the thermal resistance value of the white spot thermal resistance.

[0067] Specifically, determine whether the thermal resistance value of the white spot is greater than 0; if not, determine that there is no white spot; if yes, determine that there is a white spot; take the sector-shaped micro-element where the thermal resistance of the white spot is located as the location of the white spot.

[0068] The hypothetical principle is adopted. First, it is assumed that there is white spot thermal resistance in the insulation layer of a certain thermal resistance branch. If the calculated white spot thermal resistance is 0, it means that the white spot thermal resistance does not exist. If the calculated white spot thermal resistance is not 0 (greater than 0), it means that the white spot thermal resistance does exist. It is assumed that the insulation layer corresponding to the thermal resistance branch where the white spot thermal resistance is located is the location where the white spot fault occurs.

[0069] It also includes: when white spots are present, calculating the thickness of the white spots based on their thermal resistance value. The thermal resistance value of the white spots is directly proportional to their thickness; the higher the thermal resistance value, the greater the thickness of the white spots.

[0070] The high-voltage cable white spot detection method provided in this application first obtains the structural parameters of the external structure of each layer of the cable, including the inner and outer diameters of the external structure; based on the structural parameters, a circular thermal circuit model of the cable is established, which is the cross-section of the cable. The cross-section is divided into multiple sector-shaped micro-elements, each sector-shaped micro-element including multiple thermal resistance branches extending from the conductor to the outer sheath, and each thermal resistance branch including a structural thermal resistance corresponding to the external structure; at least one thermal resistance branch also includes white spot thermal resistance; for each thermal resistance branch, the thermal resistance value of the structural thermal resistance on each thermal resistance branch is calculated based on the arc of the sector-shaped micro-element and the structural parameters; the cable surface temperature, conductor temperature, and conductor load current value corresponding to each thermal resistance branch are measured; the total heat flow of the cable is calculated based on the conductor temperature and load current value; the thermal resistance value of the white spot thermal resistance is calculated based on the thermal resistance value of the structural thermal resistance, cable surface temperature, conductor temperature, and total heat flow of the cable; and the presence and location of white spots are determined based on the thermal resistance value of the white spot thermal resistance. By virtually constructing the sector-shaped micro-element containing the white spot based on the thermal circuit model, and by measuring and calculating the parameters in each sector-shaped micro-element, and qualitatively calculating the thermal resistance value of the white spot according to Fourier's heat transfer law and the thermal circuit model, it is possible to determine whether the white spot exists and its location when it exists. This allows for the detection of white spots in their early stages, guiding the timely repair of the cable with filling and repair fluid, and preventing the white spot from expanding further and causing a significant impact on the cable's operating performance.

[0071] Corresponding to the high-voltage cable white spot detection method in this application, this application also provides a high-voltage cable white spot detection device. The cable structure includes a conductor and a three-layer external structure. The external structure includes an insulation layer, a buffer layer, and an outer sheath from the inside out. The cross-section of the external structure is annular. Figure 4 is a schematic diagram of the structure of a high-voltage cable white spot detection device provided in Embodiment 3 of this application. As shown in Figure 4, the high-voltage cable white spot detection device includes:

[0072] The structural parameter acquisition module 401 is used to acquire the structural parameters of the external structure of each layer of the cable, the structural parameters including the inner diameter and outer diameter of the external structure;

[0073] The thermal circuit model construction module 402 is used to establish a circular thermal circuit model of the cable based on the structural parameters. The circular thermal circuit model is the cross-section of the cable. The cross-section is divided into multiple sector-shaped micro-elements. Each sector-shaped micro-element includes multiple thermal resistance branches extending from the conductor to the outer sheath. Each thermal resistance branch includes a structural thermal resistance that corresponds one-to-one with the external structure. At least one thermal resistance branch also includes white spot thermal resistance.

[0074] The thermal resistance calculation module 403 is used to calculate the thermal resistance value of the structural thermal resistance on each thermal resistance branch according to the radius of the sector micro-element to which it belongs and the structural parameters.

[0075] The parameter measurement module 404 is used to measure the cable surface temperature, conductor temperature, and conductor load current value corresponding to each thermal resistance branch.

[0076] The cable heat flow calculation module 405 is used to calculate the heat flow of the entire cable based on the conductor temperature and the load current value.

[0077] The white spot thermal resistance calculation module 406 is used to calculate the thermal resistance value of the white spot based on the thermal resistance value of the structure thermal resistance, the surface temperature of the cable, the conductor temperature, and the total heat flow of the cable.

[0078] The white spot qualitative module 407 is used to determine whether a white spot exists and the location of the white spot when it exists, based on the thermal resistance value of the white spot thermal resistance.

[0079] Optionally, the temperature is measured using a temperature sensor, and the high-voltage cable white spot detection device further includes:

[0080] The reading deviation acquisition module is used to acquire the reading deviation of the temperature sensor.

[0081] The deviation judgment module is used to determine whether the reading deviation of the temperature sensor is less than a preset deviation range; if so, the parameter measurement module 404 is executed.

[0082] Optionally, the white spot thermal resistance calculation module 406 includes:

[0083] The linear matrix formula construction submodule is used to construct and calculate the linear matrix formula based on Fourier's heat transfer law and the circular thermal path model. The linear matrix formula includes the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, the total heat flux of the cable, and the white spot thermal resistance.

[0084] The white spot thermal resistance calculation submodule is used to substitute the values ​​of the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, and the total heat flux of the cable into the linear matrix formula to obtain the thermal resistance value of the white spot.

[0085] Optionally, the vitiligo qualitative module 407 includes:

[0086] The thermal resistance determination submodule determines whether the thermal resistance value of the white spot thermal resistance is greater than 0.

[0087] The first qualitative submodule is used to determine that there is no white spot if the thermal resistance value of the white spot thermal resistance is 0.

[0088] The second qualitative submodule is used to determine the presence of a white spot if the thermal resistance value of the white spot thermal resistance is greater than 0.

[0089] The sector-shaped micro-element where the thermal resistance of the white spot is located is taken as the location of the white spot.

[0090] Optionally, the high-voltage cable white spot detection device also includes:

[0091] The thickness detection module is used to calculate the thickness of the white spot based on its thermal resistance value when a white spot is present.

[0092] The high-voltage cable white spot detection device provided in this application embodiment can execute the high-voltage cable white spot detection method provided in any embodiment of this application, and has the corresponding functional modules and beneficial effects of the method.

[0093] Figure 5 illustrates a schematic diagram of an electronic device 40 that can be used to implement embodiments of this application. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the application described and / or claimed herein.

[0094] As shown in Figure 5, the electronic device 40 includes at least one processor 41 and a memory, such as a read-only memory (ROM) 42 and a random access memory (RAM) 43, communicatively connected to the at least one processor 41. The memory stores computer programs executable by the at least one processor. The processor 41 can perform various appropriate actions and processes based on the computer program stored in the ROM 42 or loaded into the RAM 43 from storage unit 48. The RAM 43 can also store various programs and data required for the operation of the electronic device 40. The processor 41, ROM 42, and RAM 43 are interconnected via a bus 44. An input / output (I / O) interface 45 is also connected to the bus 44.

[0095] Multiple components in electronic device 40 are connected to I / O interface 45, including: input unit 46, such as keyboard, mouse, etc.; output unit 47, such as various types of monitors, speakers, etc.; storage unit 48, such as disk, optical disk, etc.; and communication unit 49, such as network card, modem, wireless transceiver, etc. Communication unit 49 allows electronic device 40 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0096] Processor 41 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 41 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 41 performs the various methods and processes described above, such as the white spot detection method for high-voltage cables.

[0097] In some embodiments, the high-voltage cable white spot detection method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 48. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 40 via ROM 42 and / or communication unit 49. When the computer program is loaded into RAM 43 and executed by processor 41, one or more steps of the high-voltage cable white spot detection method described above may be performed. Alternatively, in other embodiments, processor 41 may be configured to perform the high-voltage cable white spot detection method by any other suitable means (e.g., by means of firmware).

[0098] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0099] Computer programs used to implement the methods of this application may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0100] In the context of this application, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. The storage medium can be a non-transitory storage medium.

[0101] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0102] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0103] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0104] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.

[0105] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method of detecting white spot in a high voltage cable, wherein, The cable structure includes a conductor and a three-layer outer structure. The outer structure, from the inside out, includes an insulation layer, a buffer layer, and an outer sheath. The cross-section of the outer structure is annular. The method includes: Obtain the structural parameters of the external structure of each layer of the cable, including the inner and outer diameters of the external structure; A circular thermal circuit model of the cable is established based on the structural parameters. The circular thermal circuit model is the cross-section of the cable. The cross-section is divided into multiple sector-shaped micro-elements. Each sector-shaped micro-element includes multiple thermal resistance branches extending from the conductor to the outer sheath. Each thermal resistance branch includes a structural thermal resistance that corresponds one-to-one with the external structure. At least one thermal resistance branch also includes white spot thermal resistance. For each thermal resistance branch, the thermal resistance value of the structural thermal resistance on each thermal resistance branch is calculated based on the radii of the corresponding sector micro-element and the structural parameters. Measure the cable surface temperature, conductor temperature, and conductor load current value corresponding to each thermal resistance branch; Calculate the total heat flow of the cable based on the conductor temperature and the load current value; The thermal resistance of the white spot is calculated based on the thermal resistance value of the structure, the surface temperature of the cable, the conductor temperature, and the total heat flow of the cable. The presence and location of white spots are determined based on the thermal resistance value of the white spot thermal resistance.

2. The high voltage cable whitening detection method of claim 1, wherein, The thermal resistance value of the structural thermal resistance on each of the thermal resistance branches is calculated according to the following formula: Wherein, i is the serial number of the fan-shaped microelement to which the thermal resistance branch belongs, i = 1, 2…N s , N s is the number of the fan-shaped microelement; j is the number of layers of the external structure in the fan-shaped microelement, j = 1, 2, 3, λ i is the thermal conductivity, θ is the radian of the fan-shaped microelement, r jw is the outer diameter of the jth layer of the external structure, r jn is the inner diameter of the jth layer of the external structure, T ij is the thermal resistance value of the corresponding structural thermal resistance of the jth layer of the external structure in the ith fan-shaped microelement.

3. The high voltage cable whitening detection method of claim 1, wherein, Temperature is measured using a temperature sensor. Before measuring the cable surface temperature, conductor temperature, and conductor load current value corresponding to each of the aforementioned thermal resistance branches, the following steps are also included: Obtain the reading deviation of the temperature sensor; Determine whether the reading deviation of the temperature sensor is less than a preset deviation range; If so, then perform the steps of measuring the cable surface temperature, conductor temperature, and conductor load current value corresponding to each of the aforementioned thermal resistance branches.

4. The high voltage cable whitening detection method of claim 1, wherein, The formula for calculating the cable total heat flow is as follows: Q = I 2 R; R = R0[1 + a 20 (θ c - 20)][1 + y s + y p ]; Wherein, Q is the total heat flow of the cable, I is the load current value, R is the AC resistance value of the conductor, R0, a 20 is the DC resistance of the conductor at 20°C, the temperature coefficient, θ c is the conductor temperature, y s , y p are the known skin effect factor, proximity effect factor.

5. The high voltage cable whitening detection method of claim 1, wherein, The thermal resistance value of the white spot is calculated based on the thermal resistance value of the structure, the surface temperature of the cable, the conductor temperature, and the total heat flow of the cable, including: The linear matrix formula is constructed based on Fourier's heat transfer law and the circular thermal path model. The linear matrix formula includes the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, the total heat flux of the cable, and the white spot thermal resistance. The thermal resistance value of the white spot thermal resistance is obtained by substituting the values ​​of the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, and the total heat flux of the cable into the linear matrix formula.

6. The high voltage cable whitening detection method of claim 1, wherein, The step of determining the presence and location of white spots based on the thermal resistance value of the white spot thermal resistance includes: Determine whether the thermal resistance value of the white spot is greater than 0; If not, then the white patches are definitely not present; If so, then vitiligo is confirmed. The sector-shaped micro-element where the thermal resistance of the white spot is located is taken as the location of the white spot.

7. The high voltage cable whitening detection method of any one of claims 1-6, wherein, Also includes: When white spots are present, the thickness of the white spots is calculated based on the thermal resistance value of the white spots.

8. A high voltage cable white spot detection apparatus, wherein, The cable structure includes a conductor and a three-layer outer structure. The outer structure, from the inside out, includes an insulation layer, a buffer layer, and an outer sheath. The cross-section of the outer structure is annular. The device includes: The structural parameter acquisition module is configured to acquire the structural parameters of the external structure of each layer of the cable, the structural parameters including the inner diameter and outer diameter of the external structure; The thermal circuit model construction module is configured to build a circular thermal circuit model of the cable based on the structural parameters. The circular thermal circuit model is the cross-section of the cable, which is divided into multiple sector-shaped micro-elements. Each sector-shaped micro-element includes multiple thermal resistance branches extending from the conductor to the outer sheath. Each thermal resistance branch includes a structural thermal resistance that corresponds one-to-one with the external structure. At least one thermal resistance branch also includes white spot thermal resistance. The thermal resistance calculation module is configured to calculate the thermal resistance value of the structural thermal resistance on each thermal resistance branch based on the radius of the corresponding sector micro-element and the structural parameters. The parameter measurement module is configured to measure the cable surface temperature, conductor temperature, and conductor load current value corresponding to each thermal resistance branch. The cable heat flow calculation module is configured to calculate the total heat flow of the cable based on the conductor temperature and the load current value. The white spot thermal resistance calculation module is configured to calculate the thermal resistance value of the white spot based on the thermal resistance value of the structure, the surface temperature of the cable, the conductor temperature, and the total heat flow of the cable. The white spot qualitative module is configured to determine whether a white spot exists and its location when it exists based on the thermal resistance value of the white spot thermal resistance.

9. An electronic device, comprising: At least one processor; as well as A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the high-voltage cable white spot detection method according to any one of claims 1-7.

10. A computer readable storage medium, wherein, The computer-readable storage medium stores computer instructions that cause a processor to execute the high-voltage cable white spot detection method according to any one of claims 1-7.

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