CN112906195B - Conductor temperature calculation method, system, equipment and storage medium for cable connector - Google Patents
Conductor temperature calculation method, system, equipment and storage medium for cable connector Download PDFInfo
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- 239000004020 conductor Substances 0.000 title claims abstract description 114
- 238000004364 calculation method Methods 0.000 title claims abstract description 76
- 238000000034 method Methods 0.000 claims abstract description 41
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 43
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 17
- 239000004800 polyvinyl chloride Substances 0.000 claims description 17
- 229910052802 copper Inorganic materials 0.000 claims description 16
- 239000010949 copper Substances 0.000 claims description 16
- 238000009413 insulation Methods 0.000 claims description 16
- 239000000565 sealant Substances 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- 229910052782 aluminium Inorganic materials 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- 239000012212 insulator Substances 0.000 claims description 3
- 238000004891 communication Methods 0.000 claims description 2
- 238000012546 transfer Methods 0.000 abstract description 9
- 230000007613 environmental effect Effects 0.000 abstract description 6
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- 230000008569 process Effects 0.000 description 7
- 230000009286 beneficial effect Effects 0.000 description 6
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- 230000008859 change Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 238000004088 simulation Methods 0.000 description 3
- 238000009529 body temperature measurement Methods 0.000 description 2
- 229920003020 cross-linked polyethylene Polymers 0.000 description 2
- 239000004703 cross-linked polyethylene Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
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- 238000005516 engineering process Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2113/00—Details relating to the application field
- G06F2113/16—Cables, cable trees or wire harnesses
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
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Abstract
The invention discloses a conductor temperature calculation method, a system, equipment and a storage medium of a cable joint, wherein the method comprises the following steps: segmenting the cable connector according to the structural characteristics of the cable connector, and segmenting the cable body at equal intervals; constructing an axial thermal path model based on the segmented cable joint and the cable body; based on the axial thermal path model, the current surface temperature of the cable connector and the cable body is used as input data of the model, and the conductor temperature of the cable connector and the cable body is obtained. The axial thermal circuit model established by the invention considers the axial heat transfer between the cable joint and the cable body, and improves the accuracy of conductor temperature calculation; meanwhile, the axial thermal path model does not need to consider the environmental thermal influence, so that the difficulty of model solving is reduced; the invention also discloses a method for carrying out sectional modeling based on the structural characteristics of the cable joint, which can reduce calculation errors and improve the accuracy of conductor temperature calculation.
Description
Technical Field
The present invention relates to the field of cable temperature measurement technologies, and in particular, to a method, a system, an apparatus, and a storage medium for calculating a conductor temperature of a cable joint.
Background
With the development of national economy, the power demand is increasing, and more high-voltage cables are used for power transmission lines. Researches show that the cable joint is the weakest position in the circuit, and the contact resistance at the crimping pipe is overlarge due to the problems of installation process defects, poor construction and the like, so that the heat generation amount at the joint is far greater than that of the cable body. The cable joint is large in insulation thickness, heat dissipation is not facilitated, the temperature of a conductor of the cable joint is increased, the cable joint is a bottleneck point for limiting the current-carrying capacity to be increased, and faults such as thermal breakdown of the joint can be caused when the cable joint is severe. Therefore, obtaining accurate conductor temperature data is of great importance in maintaining safe and stable operation of the cable system.
The international electrotechnical commission has established IEC-60853 and IEC-60287 standards, which can be used to calculate the transient and steady state temperatures, respectively, of a cable conductor, but it does not establish a cable joint conductor temperature calculation method.
Compared with the cable body, the cable connector has more complex structure, and the result is unreliable by directly applying the cable body conductor temperature calculation method to connector conductor temperature calculation. With the development of computers, a method for calculating the conductor temperature of a cable joint by using numerical simulation is proposed, but the modeling process is complex and is not beneficial to practical application. Some scholars establish a conductor temperature calculation model of the cable joint based on a thermal path method, and obtain an expression of the conductor temperature and the environment temperature by adopting modes such as curve fitting, but because the cable joint is large in size and slow in heat dissipation, the conductor temperature is higher than the temperature of the cable body, temperature difference exists between the conductor temperature and the cable body, copper is a good conductor of heat, and part of heat of the cable joint flows out from the joint to the cable body along a copper core and dissipates heat through the cable body. Therefore, if the axial heat flow is not considered, the calculation result of the conductor temperature of the cable joint is higher, and the calculation result of the conductor temperature of the cable adjacent to the cable joint is lower.
In summary, the current cable joint conductor temperature calculation has the following defects:
(1) The existing calculation method or model does not consider the problem of axial heat transfer between the cable joint and the cable body, and if the simulation method is adopted to model complex, the accuracy of the model depends on the applied boundary conditions.
(2) The existing calculation method or model considers environmental thermal parameters, but the accuracy of the parameters is difficult to ensure in the environment change test in the actual engineering;
(3) The existing calculation method or model takes the cable joint as a whole, but the joint structure is complex, the radial thermal resistances of different structures are inconsistent, thus the measured temperature of the conductor is error, and the result is inaccurate.
Disclosure of Invention
The present invention aims to at least solve the technical problems existing in the prior art. Therefore, the invention provides a conductor temperature calculation method, a system, equipment and a storage medium for a cable joint, which can improve the accuracy of conductor temperature calculation.
In a first aspect of the present invention, there is provided a conductor temperature calculation method for a cable joint, comprising the steps of:
segmenting the cable connector according to structural characteristics of the cable connector, segmenting the cable body at equal intervals, wherein the structural characteristics comprise the thickness of main insulation of the cable connector;
constructing an axial thermal path model based on the segmented cable joint and the cable body;
and based on the axial thermal path model, taking the current surface temperatures of the cable joint and the cable body as input data of the model to obtain the conductor temperatures of the cable joint and the cable body.
According to the embodiment of the invention, at least the following technical effects are achieved:
(1) The axial thermal circuit model established in the method does not need to consider the influence of the environment, and the surface temperature of the cable connector and the cable body is used as the input quantity of the model, so that the temperature of the conductor can be calculated, and the difficulty of solving the model is reduced;
(2) The axial thermal path model established in the method considers the axial heat transfer between the cable joint and the cable body, solves the problems that the conductor temperature calculation of the cable joint is higher and the conductor temperature calculation of the body section adjacent to the cable joint is lower, and ensures that the conductor temperature calculation result is more accurate;
(3) According to the method, the sectional modeling is carried out based on the structural characteristics of the cable joint (namely the thickness of the main insulation of the cable joint), so that the calculation error can be reduced, the accuracy of conductor temperature calculation is improved, and the method is beneficial to practical engineering application.
According to some embodiments of the present invention, the construction process of the axial thermal path model includes the following steps:
acquiring the loss of a copper core of the cable as the radial heat flow flowing in;
calculating the axial heat flow according to the conductor temperature difference between two adjacent sections;
establishing a heat balance model for keeping the heat flow flowing out of each section consistent with the heat flow flowing in;
based on the heat balance model, calculating the radial heat flow flowing out;
and constructing an axial thermal path model based on a thermal path method and the thermal balance model, and converging the axial thermal path model.
According to some embodiments of the invention, the current surface temperatures of the cable joint and the cable body are obtained by several temperature sensors provided on the cable joint and the cable body surface.
According to some embodiments of the invention, each segment of the surface of the cable joint and the cable body is provided with three of the temperature sensors.
According to some embodiments of the invention, the temperature sensors of each segment of the surface are circumferentially spaced apart by 120 °.
In a second aspect of the present invention, there is provided a conductor temperature calculation system of a cable joint, comprising:
the sectioning unit is used for sectioning the cable joint according to the structural characteristics of the cable joint, sectioning the cable body at equal intervals, wherein the structural characteristics comprise the thickness of main insulation of the cable joint;
the axial thermal path model building unit is used for building an axial thermal path model based on the segmented cable joint and the cable body;
and the conductor temperature calculation unit is used for obtaining the conductor temperatures of the cable joint and the cable body by taking the current surface temperatures of the cable joint and the cable body as input data of the model based on the axial thermal path model.
According to the embodiment of the invention, at least the following technical effects are achieved:
(1) The axial thermal circuit model established in the system can calculate the conductor temperature without considering the influence of the environmental temperature and takes the surface temperature of the cable connector and the cable body as the input quantity of the model, thereby reducing the difficulty of solving the model;
(2) The axial thermal path model established in the system considers the axial heat transfer between the cable joint and the cable body, solves the problems that the conductor temperature calculation of the cable joint is higher and the conductor temperature calculation of the body section adjacent to the cable joint is lower, and ensures that the conductor temperature calculation result is more accurate;
(3) The system carries out sectional modeling based on the structural characteristics of the cable joint (namely the thickness of the main insulation of the cable joint), can reduce calculation errors, improves the accuracy of conductor temperature calculation, and is beneficial to engineering practical application.
In a third aspect of the present invention, there is provided a conductor temperature calculating apparatus of a cable joint, comprising: at least one control processor and a memory for communication connection with the at least one control processor; the memory stores instructions executable by the at least one control processor to enable the at least one control processor to perform the conductor temperature calculation method of the cable tie according to the first aspect of the invention.
In a fourth aspect of the present invention, there is provided a computer-readable storage medium storing computer-executable instructions for causing a computer to perform the conductor temperature calculation method of the cable joint according to the first aspect of the present invention.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
fig. 1 is a schematic flow chart of a method for calculating a conductor temperature of a cable connector according to a first embodiment of the present invention;
FIG. 2 is a schematic diagram of a complete flow of axial thermal model construction according to a first embodiment of the present invention;
FIG. 3 is a schematic sectional view of a cable connector according to a second embodiment of the present invention;
FIG. 4 is a schematic diagram of an axial thermal circuit model according to a second embodiment of the present invention;
description of the reference numerals:
100. a copper shell cushion block; 200. AB pouring sealant; 300. PVC waterproof tape; 400. a stress cone; 500. the joint is mainly insulated; 600. a high voltage shielding tube; 700. a metal shield; 800. a metal connecting pipe; 900. a cable copper core; 1000. the cable is mainly insulating crosslinked polyethylene.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
A first embodiment;
the following defects exist in the current cable joint conductor temperature calculation scheme:
(1) The existing calculation method or model does not consider the problem of axial heat transfer between the cable joint and the cable body, and if the modeling by adopting the simulation method is complex, the accuracy of the model depends on the applied boundary condition; (2) The existing calculation method or model considers environmental thermal parameters, but the accuracy of the parameters is difficult to ensure in the environment change test in the actual engineering; (3) The existing calculation method or model takes the cable joint as a whole, but the joint structure is complex, the radial thermal resistances of different structures are inconsistent, thus the measured temperature of the conductor is error, and the result is inaccurate.
Referring to fig. 1, in one embodiment of the present invention, there is provided a conductor temperature calculating method of a cable joint, a port of which is connected to a cable body, comprising the steps of:
s100, segmenting the cable connector according to structural characteristics of the cable connector, segmenting the cable body at equal intervals, wherein the structural characteristics comprise the thickness of main insulation of the cable connector;
s200, constructing an axial thermal path model based on the segmented cable joint and the cable body;
s300, based on the axial thermal path model, the current surface temperature of the cable joint and the current surface temperature of the cable body are used as input data of the model, and the conductor temperature of the cable joint and the conductor temperature of the cable body are obtained.
The method comprises the steps of firstly segmenting the cable connector according to the structural characteristics of the cable connector (namely the thickness of main insulation of the cable connector), segmenting the cable body at equal intervals, constructing a segmented axial thermal path model, and improving the accuracy of a measurement result; then, an axial thermal path model is built, a thermal balance equation for keeping the heat flow flowing out of each section consistent with the heat flow flowing in is arranged in the axial thermal path model, for any section, the heat flow flowing in the section is kept consistent with the heat flow flowing out of the section, the thermal balance equation of each section is connected, and the axial thermal path model is obtained, and comprises a cable joint and a relational expression of the conductor temperature and the surface temperature of the cable body; and finally, taking the current surface temperatures of the cable joint and the cable body as input data, inputting the input data into the axial thermal path model, and finally obtaining data output by the axial thermal path model, wherein the output data is the conductor temperatures of the cable joint and the cable body.
(1) The existing calculation method or model considers environmental thermal parameters, but the accuracy of the parameters is difficult to ensure in the environment change test in the actual engineering. The axial thermal circuit model established in the embodiment can calculate the conductor temperature without considering the influence of the environment by taking the surface temperature of the cable connector and the cable body as the input quantity of the model, thereby reducing the difficulty of solving the model;
(2) The existing calculation method or model does not consider the problem of axial heat transfer between the cable joint and the cable body, so that the calculation result of the conductor temperature of the cable joint is higher, and the calculation result of the conductor temperature of the cable adjacent to the cable joint is lower. The axial thermal path model established in the embodiment considers the axial heat transfer between the cable joint and the cable body, solves the problems that the conductor temperature calculation of the cable joint is higher and the conductor temperature calculation of the body section adjacent to the cable joint is lower, and ensures that the conductor temperature calculation result is more accurate;
(3) The existing calculation method or model takes the cable joint as a whole, but the joint structure is complex, the radial thermal resistances of different structures are inconsistent, thus the measured temperature of the conductor is error, and the result is inaccurate. In the embodiment, the sectional modeling is performed based on the structural characteristics of the cable joint (namely the thickness of the main insulation of the cable joint), so that the calculation error can be reduced, the accuracy of conductor temperature calculation is improved, and the method is beneficial to practical engineering application.
Referring to fig. 2, based on the above embodiment, the construction process of the axial thermal path model includes the following steps:
acquiring the loss of a copper core of the cable as the radial heat flow flowing in;
calculating the axial heat flow according to the conductor temperature difference between two adjacent sections;
establishing a heat balance equation heat balance model for keeping the heat flow flowing out of each section consistent with the heat flow flowing in;
based on the heat balance model, calculating the radial heat flow flowing out;
and constructing an axial thermal path model based on the thermal path method and the thermal balance model, and converging the axial thermal path model.
In fig. 2, the radial heat flow in: cable copper core loss; radial heat flow out: (conductor temperature-surface temperature)/radial thermal resistance; the inflow axial heat flow: the ratio of the temperature difference between two adjacent sections of the cable copper core to the axial thermal resistance; the axial heat flow out: the ratio of the temperature difference between two adjacent sections of the copper core of the cable to the axial thermal resistance.
Based on the above embodiments, the current surface temperatures of the cable joint and the cable body are obtained by several temperature sensors provided on the surfaces of the cable joint and the cable body. The current surface temperature of the cable connector and the cable body can be accurately obtained through a plurality of temperature sensors.
Based on the above embodiment, three temperature sensors are provided for each section of surface of the cable connector and the cable body. For example, the cable joint is divided into 7 sections, the cable body is divided into 12 sections, 19 temperature measuring points are arranged on the cable joint and the cable body, three temperature sensors are placed on each temperature measuring point, and the temperature sensors are distributed at intervals of 120 degrees along the circumference. And the accuracy of the current surface temperature data is improved, so that the accuracy of the final calculated conductor temperature is improved.
A second embodiment;
in order for those skilled in the art to understand the above first embodiment, referring to fig. 2 to 4, an embodiment of the present invention provides a method for calculating a conductor temperature of a cable joint (taking a cold-shrink cable joint as an example), the method comprising the steps of:
firstly, segmenting a cable connector according to structural characteristics;
as shown in fig. 3, 100 is a copper shell cushion block, 200 is an AB pouring sealant, 300 is a PVC waterproof tape, 400 is a stress cone, 500 is a joint main insulation, 600 is a high-voltage shielding pipe, 700 is a metal shielding cover, 800 is a metal connecting pipe, 900 is a cable copper core, and 1000 is a cable main insulation crosslinked polyethylene. The cable joint is divided into a long end and a short end, the left half part is the joint long end, the right half part is the joint short end in fig. 3 by taking the crimping pipe as the center, and the joint is divided into A, B, C, D, E, F, G seven sections according to structural characteristics, wherein A is the crimping section; b is an insulation section of the long-end main body of the joint, and the insulation section extends from the tail end of the crimping pipe to the left end port of the joint; c is a long end section of the copper shell, and extends from the left end opening of the joint to the tail end of the long end copper shell; d is a cushion block section; e is the insulating section of the short-end main body of the connector, F is the short-end section of the copper shell from the tail end of the crimping pipe to the right end port of the connector, G is the cushion block section from the right end port of the connector to the tail end of the short-end copper shell.
Secondly, segmenting the cable bodies connected with the two ends of the cable connector at equal intervals;
the cables adjacent to the two ends of the cable joint are H sections, the cable body sections are divided again for more accurately calculating the conductor temperature of the cables adjacent to the joint, the length of each section of cable is 0.5m, 6 sections are respectively arranged at the left end and the right end of the cable joint, and 12 sections are all sequentially named as H1 to H12.
Thirdly, establishing an axial thermal circuit model based on the cable connector and the cable body;
an axial thermal path model of the cable joint is built as shown in fig. 4. Since the connector long and short ends are structurally symmetrical, fig. 4 only shows the cable connector short end model of A, E, F, G, H in fig. 3, as is the model of the long end section. The section A sequentially comprises a metal connecting pipe, an air layer, a metal shielding cover, a high-voltage shielding pipe, a joint main insulator, a PVC (polyvinyl chloride) belt, an AB pouring sealant layer and a copper protection shell layer from inside to outside; the length of the section B is different from that of the section E, but the structure is the same, and 5 layers from inside to outside are a cable main insulating layer, a joint main insulating layer, a PVC (polyvinyl chloride) belt, an AB pouring sealant layer and a copper protection shell layer in sequence; the length of the section C is different from that of the section F, but the structure is the same, and 4 layers from inside to outside are a cable main insulating layer, a PVC tape layer, an AB pouring sealant layer and a copper protection shell layer in sequence; the structures and the lengths of the sections D and G are the same, and 2 layers from inside to outside are a main cable insulating layer and a cushion block layer in sequence; the H section is sequentially provided with a cable main insulating layer, an insulating shielding layer, a wrapping layer, an air gap layer, an aluminum sheath layer and an outer sheath layer from inside to outside 6 layers.
Step four, calculating radial thermal resistance of each section;
the radial thermal resistance of each section is calculated, and the calculation formula of the radial thermal resistance of the j-th section is as follows:
wherein Δz j Lambda is the length of the j-th segment i Is the heat conductivity coefficient of the ith layer, r i+1 Radius of the (i+1) th layer, r i Is the radius of the i-th layer.
(5) Calculating the axial thermal resistance of each section;
the axial thermal resistance of each section is calculated, and the calculation formula of the axial thermal resistance of the jth section is as follows:
wherein Δz j Lambda is the length of the j-th segment c Is the heat conductivity coefficient of the copper core, r c Is the radius of the copper core.
(6) Calculating radial heat flow of each section of cable copper core;
calculating radial heat flow of each section of cable copper core:
wherein the method comprises the steps ofK is the contact coefficient of the pressure connection pipe, R is the alternating current resistance of the copper core at 20 ℃, theta ci The conductor temperature of the I-th section is I, and the conductor current is I.
(7) Calculating the axial heat flow of each section of cable copper core;
in calculating the axial heat flow of each section of cable copper core, the axial heat flow flows to two sides because the central temperature of the crimping pipe is highest, and the axial heat flow flowing from the crimping pipe to the short end of the joint is half of the total heat flow, so the equivalent is that the axial heat resistance is twice of the total heat resistance.
(8) Based on the axial thermal path model and a thermal equilibrium equation, obtaining a relational expression of the cable joint and the temperature and the surface temperature of the body conductor:
at the end of the cable, the axial heat flow flowing out of the node is not considered at the end of the cable, and only the axial heat flow flowing into the node is considered, because the temperature difference between the end section and the next section is small, so that the axial heat flow is small, and the influence of the axial heat flow flowing out can be ignored.
(9) Iterative solution process;
iterative solving process: and inputting the surface temperatures of the cable joint and the cable body into the model, and solving by numerical calculation software (such as MATLAB) to obtain the conductor temperature value. The initial temperature of the input conductor in the model is 90 ℃, the iteration is carried out forward from the end of the cable in sequence, the measurement error according to the temperature sensor is 0.5 ℃, and therefore the judgment condition of iteration convergence is set asI.e. the numerical calculation error between the current iteration and the previous iteration of the conductor temperature of the same section is within 0.5 ℃.
The surface temperature is obtained by temperature sensors arranged on the surfaces of the cable connector and the body, the temperature sensors are arranged on 7 sites on the cable connector, one temperature sensor is arranged on the cable body adjacent to the cable connector at intervals of 0.5m, 6 sites are arranged on each cable at each end, and 19 temperature measurement points are arranged in total.
It should be noted that the segments of the cable joint according to the present embodiment may be further finely divided according to the structural characteristics (i.e. the thickness of the main insulation of the cable joint), and the different types of joint segments may also differ.
The beneficial effects that this embodiment produced:
(1) The existing calculation method or model considers environmental thermal parameters, but the accuracy of the parameters is difficult to ensure in the environment change test in the actual engineering. The axial thermal circuit model established in the embodiment can calculate the conductor temperature without considering the influence of the environment by taking the surface temperature of the cable connector and the cable body as the input quantity of the model, thereby reducing the difficulty of solving the model;
(2) The existing calculation method or model does not consider the problem of axial heat transfer between the cable joint and the cable body, so that the calculation result of the conductor temperature of the cable joint is higher, and the calculation result of the conductor temperature of the cable adjacent to the cable joint is lower. The axial thermal path model established in the embodiment considers the axial heat transfer between the cable joint and the cable body, solves the problems that the conductor temperature calculation of the cable joint is higher and the conductor temperature calculation of the body section adjacent to the cable joint is lower, and ensures that the conductor temperature calculation result is more accurate;
(3) In the embodiment, the sectional modeling is performed based on the structural characteristics of the cable joint, so that calculation errors can be reduced, the accuracy of conductor temperature calculation is improved, and the method is beneficial to engineering practical application.
A third embodiment;
an embodiment of the present invention provides a conductor temperature calculation system of a cable joint, including: the device comprises a segmentation unit, an axial thermal path model construction unit and a conductor temperature calculation unit, wherein:
the segmentation unit is used for segmenting the cable connector according to the structural characteristics of the cable connector, and segmenting the cable body at equal intervals, wherein the structural characteristics comprise the thickness of main insulation of the cable connector;
the axial thermal path model building unit is used for building an axial thermal path model based on the segmented cable joint and the cable body;
the conductor temperature calculation unit is used for obtaining the conductor temperature of the cable joint and the cable body based on the axial thermal path model and by taking the current surface temperature of the cable joint and the current surface temperature of the cable body as input data of the model.
It should be noted that, the embodiment of the present system and the embodiment of the method are based on the same inventive concept, and the related content of the embodiment of the method is also applicable to the embodiment of the present system, which is not repeated herein.
A fourth embodiment;
in one embodiment of the present invention, a conductor temperature computing device of a cable joint is provided, which may be any type of intelligent terminal, such as a mobile phone, a tablet computer, a personal computer, etc.
Specifically, the conductor temperature calculation apparatus of the cable joint includes: one or more control processors and memory. The control processor and the memory may be connected by a bus or other means.
The memory is used as a non-transitory computer readable storage medium for storing non-transitory software programs, non-transitory computer executable programs and modules, such as program instructions/modules corresponding to the conductor temperature computing device of the cable connector in the embodiments of the present invention. The control processor executes various functional applications and data processing of the conductor temperature calculation system of the cable joint by running non-transitory software programs, instructions and modules stored in the memory, namely, the conductor temperature calculation method of the cable joint of the method embodiment is realized.
The memory may include a memory program area and a memory data area, wherein the memory program area may store an operating system, at least one application program required for a function; the stored data area may store data created from the use of the conductor temperature computing system of the cable joint, etc. In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory optionally includes memory remotely located relative to the control processor, which may be connected to the conductor temperature calculation device of the cable connector via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The one or more modules are stored in the memory and when executed by the one or more control processors perform the conductor temperature calculation method of the cable joint in the method embodiment described above.
Embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions that are executed by one or more control processors to cause the one or more control processors to perform the method for calculating the conductor temperature of a cable joint in the method embodiment.
The above described embodiments of the apparatus are only illustrative, wherein the units described as separate components may or may not be physically separate, i.e. may be located in one place, or may be distributed over a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
From the above description of embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented in software plus a general purpose hardware platform. Those skilled in the art will appreciate that all or part of the processes implementing the methods of the above embodiments may be implemented by a computer program for instructing relevant hardware, where the program may be stored in a computer readable storage medium, and where the program, when executed, may include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read Only Memory (ROM), a random access Memory (Random Access Memory, RAM), or the like. In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.
Claims (7)
1. The conductor temperature calculation method of the cable joint, the port of the said cable joint is connected with cable body, characterized by, comprising the following steps:
segmenting the cable connector according to structural characteristics of the cable connector, segmenting the cable body at equal intervals, wherein the structural characteristics comprise the thickness of main insulation of the cable connector; the cable connector is divided into A, B, C, D, E, F, G sections, and the cable body is an H section; the section A sequentially comprises a metal connecting pipe, an air layer, a metal shielding cover, a high-voltage shielding pipe, a joint main insulator, a PVC (polyvinyl chloride) belt, an AB pouring sealant layer and a copper protection shell layer from inside to outside; the length of the section B is different from that of the section E, but the structure is the same, and 5 layers from inside to outside are a cable main insulating layer, a joint main insulating layer, a PVC (polyvinyl chloride) belt, an AB pouring sealant layer and a copper protection shell layer in sequence; the length of the section C is different from that of the section F, but the structure is the same, and 4 layers from inside to outside are a cable main insulating layer, a PVC tape layer, an AB pouring sealant layer and a copper protection shell layer in sequence; the structures and the lengths of the sections D and G are the same, and 2 layers from inside to outside are a main cable insulating layer and a cushion block layer in sequence; the H section is sequentially provided with a cable main insulating layer, an insulating shielding layer, a wrapping layer, an air gap layer, an aluminum sheath layer and an outer sheath layer from inside to outside; the H section is provided with 6 sections at two ends of the cable joint respectively;
constructing an axial thermal path model based on the segmented cable joint and the cable body;
the constructing an axial thermal path model based on the segmented cable joint and the segmented cable body comprises:
acquiring the loss of a copper core of the cable as the radial heat flow flowing in;
calculating the axial heat flow according to the conductor temperature difference between two adjacent sections;
establishing a heat balance model for keeping the heat flow flowing out of each section consistent with the heat flow flowing in;
based on the heat balance model, calculating the radial heat flow flowing out;
constructing an axial thermal path model based on a thermal path method and the thermal balance model, and converging the axial thermal path model;
calculating radial thermal resistance of each segment, whereinRadial thermal resistance of segment->The calculation formula is as follows:
wherein,is->Length of segment->Is->Thermal conductivity of the layer>Is->Radius of layer>Is->Radius of the layer; />The number of layers is the number of layers;
calculating the axial thermal resistance of each segment, whereinAxial thermal resistance of the segment->The calculation formula is as follows:
wherein,is the heat conductivity of the copper core +.>Is the radius of the copper core;
calculating radial heat flow of copper cores of all sections of cables：
Wherein,for the contact coefficient of the crimp tube, +.>An alternating current resistance of the copper core at 20℃, [ about ]>Is->Conductor temperature of segment, < >>Is a conductor current;
calculating axial heat flow of copper core of ith section of cable；
Wherein,is->Conductor temperature of segment, < >>Is->Conductor temperature of segment, < >>Is->Axial thermal resistance of the segment;is->Conductor temperature of segment, < >>Is->Axial thermal resistance of the segment;
establishing a heat balance model for keeping the heat flow flowing out of each section consistent with the heat flow flowing in;
wherein,indicating the cable joint->Section, th->Section, th->Section, th->Surface temperature of the segment;respectively represent the first parts of the cable body>Section, th->Section, th->Section, th->Segment, the firstSection and->Surface temperature of the segment;
and based on the axial thermal path model, taking the current surface temperatures of the cable joint and the cable body as input data of the model to obtain the conductor temperatures of the cable joint and the cable body.
2. The method of calculating a conductor temperature of a cable joint according to claim 1, wherein the current surface temperatures of the cable joint and the cable body are obtained by a plurality of temperature sensors provided on the surfaces of the cable joint and the cable body.
3. The method of calculating the conductor temperature of a cable joint according to claim 2, wherein three of the temperature sensors are provided for each of the surfaces of the cable joint and the cable body.
4. A method of calculating the conductor temperature of a cable joint according to claim 3, wherein the temperature sensors of each segment of the surface are circumferentially spaced apart by 120 °.
5. A conductor temperature computing system for a cable connector, wherein a port of the cable connector is connected to a cable body, comprising:
the sectioning unit is used for sectioning the cable joint according to the structural characteristics of the cable joint, sectioning the cable body at equal intervals, wherein the structural characteristics comprise the thickness of main insulation of the cable joint; the cable connector is divided into A, B, C, D, E, F, G sections, and the cable body is an H section; the section A sequentially comprises a metal connecting pipe, an air layer, a metal shielding cover, a high-voltage shielding pipe, a joint main insulator, a PVC (polyvinyl chloride) belt, an AB pouring sealant layer and a copper protection shell layer from inside to outside; the length of the section B is different from that of the section E, but the structure is the same, and 5 layers from inside to outside are a cable main insulating layer, a joint main insulating layer, a PVC (polyvinyl chloride) belt, an AB pouring sealant layer and a copper protection shell layer in sequence; the length of the section C is different from that of the section F, but the structure is the same, and 4 layers from inside to outside are a cable main insulating layer, a PVC tape layer, an AB pouring sealant layer and a copper protection shell layer in sequence; the structures and the lengths of the sections D and G are the same, and 2 layers from inside to outside are a main cable insulating layer and a cushion block layer in sequence; the H section is sequentially provided with a cable main insulating layer, an insulating shielding layer, a wrapping layer, an air gap layer, an aluminum sheath layer and an outer sheath layer from inside to outside; the H section is provided with 6 sections at two ends of the cable joint respectively;
the axial thermal path model building unit is used for building an axial thermal path model based on the segmented cable joint and the cable body; the constructing an axial thermal path model based on the segmented cable joint and the segmented cable body comprises:
acquiring the loss of a copper core of the cable as the radial heat flow flowing in;
calculating the axial heat flow according to the conductor temperature difference between two adjacent sections;
establishing a heat balance model for keeping the heat flow flowing out of each section consistent with the heat flow flowing in;
based on the heat balance model, calculating the radial heat flow flowing out;
constructing an axial thermal path model based on a thermal path method and the thermal balance model, and converging the axial thermal path model;
calculating each segmentOf (3), whereinRadial thermal resistance of segment->The calculation formula is as follows:
wherein,is->Length of segment->Is->Thermal conductivity of the layer>Is->Radius of layer>Is->Radius of the layer; />The number of layers is the number of layers;
calculating the axial thermal resistance of each segment, whereinAxial thermal resistance of the segment->The calculation formula is as follows:
wherein,is the heat conductivity of the copper core +.>Is the radius of the copper core;
calculating radial heat flow of copper cores of all sections of cables：
Wherein,for the contact coefficient of the crimp tube, +.>An alternating current resistance of the copper core at 20℃, [ about ]>Is->Conductor temperature of segment, < >>Is a conductor current;
calculating axial heat of copper core of ith section of cableFlow of；
Wherein,is->Conductor temperature of segment, < >>Is->Conductor temperature of segment, < >>Is->Axial thermal resistance of the segment;is->Conductor temperature of segment, < >>Is->Axial thermal resistance of the segment;
establishing a heat balance model for keeping the heat flow flowing out of each section consistent with the heat flow flowing in;
wherein,indicating the cable joint->Section, th->Section, th->Section, th->Surface temperature of the segment;respectively represent the first parts of the cable body>Section, th->Section, th->Section, th->Segment, the firstSection and->Surface temperature of the segment;
and the conductor temperature calculation unit is used for obtaining the conductor temperatures of the cable joint and the cable body by taking the current surface temperatures of the cable joint and the cable body as input data of the model based on the axial thermal path model.
6. A conductor temperature calculation apparatus of a cable joint, comprising: at least one control processor and a memory for communication connection with the at least one control processor; the memory stores instructions executable by the at least one control processor to enable the at least one control processor to perform the conductor temperature calculation method of the cable joint of any one of claims 1 to 4.
7. A computer-readable storage medium storing computer-executable instructions for causing a computer to perform the conductor temperature calculation method of the cable joint according to any one of claims 1 to 4.
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