阅读说明：本技术 计算电缆金属套管温度的方法、装置、存储介质和处理器 (Method, device, storage medium and processor for calculating temperature of metal sleeve of cable ) 是由 王恩德 田淑均 仇天骄 马学良 郭晔 侯赞 王军 詹花茂 罗印 于 2020-05-11 设计创作，主要内容包括：本发明公开了一种计算电缆金属套管温度的方法、装置、存储介质和处理器。其中,该方法包括：采集电缆电流和缆芯电导率；获取金属套管的套管参数,其中,金属套管套设在电缆外侧,套管参数至少包括：金属套管磁导率和金属套管开缝宽度；基于缆芯电导率确定金属套管的温度计算公式,其中,金属套管的温度计算公式用于表示金属套管的温度值,与电缆电流、金属套管磁导率和金属套管开缝宽度的计算关系；基于电缆电流、缆芯电导率、金属套管磁导率、金属套管开缝宽度和金属套管的温度计算公式,确定金属套管的温度值。本发明解决了无法计算电缆穿墙金属套管温度的技术问题。(The invention discloses a method and a device for calculating the temperature of a cable metal sleeve, a storage medium and a processor. Wherein, the method comprises the following steps: collecting the current of the cable and the conductivity of the cable core; acquiring the sleeve parameters of the metal sleeve, wherein the metal sleeve is sleeved outside the cable, and the sleeve parameters at least comprise: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve; determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for expressing the temperature value of the metal sleeve and the calculation relation of the cable current, the metal sleeve magnetic conductivity and the metal sleeve slotting width; and determining the temperature value of the metal sleeve based on the cable current, the cable core conductivity, the metal sleeve magnetic conductivity, the metal sleeve slotting width and the temperature calculation formula of the metal sleeve. The invention solves the technical problem that the temperature of the cable through-wall metal sleeve cannot be calculated.)

1. A method of calculating a temperature of a metal jacket of a cable, comprising:

collecting the current of the cable and the conductivity of the cable core;

acquiring sleeve parameters of a metal sleeve, wherein the metal sleeve is sleeved outside a cable, and the sleeve parameters at least comprise: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve;

determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for representing the temperature value of the metal sleeve and the calculation relation among the cable current, the metal sleeve magnetic permeability and the metal sleeve seam width;

and determining the temperature value of the metal sleeve based on the cable current, the cable core conductivity, the metal sleeve magnetic conductivity, the metal sleeve slotting width and the temperature calculation formula of the metal sleeve.

2. The method of claim 1, further comprising:

acquiring a first preset relation between the cable current and the temperature value of the metal sleeve;

acquiring a second preset relation between the conductivity of the cable core and the temperature value of the metal sleeve;

acquiring a third preset relation between the magnetic conductivity of the metal sleeve and the temperature value of the metal sleeve;

acquiring a fourth preset relation between the slotting width of the metal sleeve and the temperature value of the metal sleeve;

and determining a temperature calculation formula of the metal sleeve based on the first preset relation, the second preset relation, the third preset relation and the fourth preset relation.

3. The method of claim 1 or 2, wherein the temperature calculation formula of the metal sleeve comprises:

when the conductivity is less than or equal to 1e6, T is 0.0512e^{0.0015I-0.035W}σ^0.144(4.1lnμ_r+20.81)-20+Tref；

When the conductivity is >1e6,

wherein T is the calculated temperature value of the metal sleeve in unit centigrade; t is_refThe starting temperature of the metal sleeve is in centigrade; w is the slotting width of the metal sleeve in mm; mu.s_rThe magnetic permeability of the metal sleeve is 1; sigma is the conductivity of the cable core and is in unit of s/m; i is the cable current in a.

4. The method of claim 1, wherein after determining the temperature value for the metal sleeve, the method further comprises:

judging whether the temperature value of the metal sleeve is higher than a preset temperature threshold value or not;

under the condition that the temperature value of the metal sleeve is determined to be higher than the preset temperature threshold, judging whether the slotting width of the metal sleeve is higher than a preset width threshold or not;

generating prompt information under the condition that the metal sleeve slotting width is determined to be higher than the preset width threshold value, wherein the prompt information represents that the temperature value of the metal sleeve is reduced by increasing the metal sleeve slotting width.

5. An apparatus for calculating the temperature of a metal jacket of a cable, comprising:

the acquisition unit is used for acquiring the current of the cable and the conductivity of the cable core;

the acquisition unit is used for acquiring sleeve parameters of a metal sleeve, wherein the metal sleeve is sleeved on the outer side of the cable, and the sleeve parameters at least comprise: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve;

the first determining unit is used for determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for representing the temperature value of the metal sleeve and the calculation relation among the cable current, the cable core conductivity, the metal sleeve magnetic permeability and the metal sleeve slotting width;

and the second determination unit is used for determining the temperature value of the metal sleeve based on the cable current, the cable core conductivity, the metal sleeve magnetic conductivity, the metal sleeve slotting width and the temperature calculation formula of the metal sleeve.

6. The apparatus of claim 5, further comprising:

the first acquisition module is used for acquiring a first preset relation between the cable current and the temperature value of the metal sleeve;

the second acquisition module is used for acquiring a second preset relation between the cable core conductivity and the temperature value of the metal sleeve;

the third acquisition module is used for acquiring a third preset relation between the magnetic permeability of the metal sleeve and the temperature value of the metal sleeve;

the fourth obtaining module is used for obtaining a fourth preset relation between the metal sleeve seam width and the temperature value of the metal sleeve;

and the determining module is used for determining a temperature calculation formula of the metal sleeve based on the first preset relation, the second preset relation, the third preset relation and the fourth preset relation.

7. The apparatus of claim 5 or 6, wherein the temperature calculation formula of the metal sleeve comprises:

when the conductivity is less than or equal to 1e6, T is 0.0512e^{0.0015I-0.035W}σ^0.144(4.1lnμ_r+20.81)-20+Tref；

When the conductivity is >1e6,

wherein T is the calculated temperature value of the metal sleeve in unit centigrade; t is_refIs the starting temperature of the metal sleeveIn degrees celsius; w is the slotting width of the metal sleeve in mm; mu.s_rThe magnetic permeability of the metal sleeve is 1; sigma is the conductivity of the cable core and is in unit of s/m; i is the cable current in a.

8. The apparatus of claim 5, further comprising:

the first judgment unit is used for judging whether the temperature value of the metal sleeve is higher than a preset temperature threshold value or not after the temperature value of the metal sleeve is determined;

the second judging unit is used for judging whether the slotting width of the metal sleeve is higher than a preset width threshold value or not under the condition that the temperature value of the metal sleeve is determined to be higher than the preset temperature threshold value;

and the prompting unit is used for generating prompting information under the condition that the metal sleeve slotting width is determined to be higher than the preset width threshold, wherein the prompting information indicates that the temperature value of the metal sleeve is reduced by increasing the metal sleeve slotting width.

9. A storage medium, characterized in that the storage medium comprises a stored program, wherein when the program runs, the device where the storage medium is located is controlled to execute the method for calculating the temperature of the metal sleeve of the cable according to any one of claims 1 to 4.

10. A processor, characterized in that the processor is configured to run a program, wherein the program is run to perform the method of calculating the temperature of a cable metal sleeve according to any one of claims 1 to 4.

Technical Field

The invention relates to the field of power transmission, in particular to a method, a device, a storage medium and a processor for calculating the temperature of a metal sleeve of a cable.

Background

When the power cable enters the transformer substation interlayer wall, a metal sleeve is adopted according to the waterproof requirement. When the single-core cable is sleeved with the metal sleeve, eddy current is formed in the metal sleeve due to electromagnetic induction, eddy current loss is generated, and the metal sleeve is heated. Because the outer sheath of the cable is contacted with the metal sleeve through the filler, the heat generated by the metal sleeve can be conducted to the outer sheath of the cable and the insulating layer of the cable, so that the aging of the outer sheath of the cable and the insulating layer is accelerated, and the outer sheath of the cable and the insulating layer are even damaged under extreme conditions, thereby causing the fault of the cable.

Eddy current losses are a major factor contributing to the problem of overheating of the wall metal bushing. The calculation of the eddy current loss and the temperature of the cable-metal sleeve system relates to the multi-physical field coupling problem of an electric field, a magnetic field and a temperature field, and has complex modeling and great calculation difficulty; in engineering, the method of slotting on the metal sleeve is often adopted to reduce eddy current loss and reduce the temperature of the metal sleeve, but no calculation basis is provided for the cooling effect and the size design of the slotting.

Aiming at the problem that the temperature of the cable wall-penetrating metal sleeve cannot be calculated, an effective solution is not provided at present.

Disclosure of Invention

The embodiment of the invention provides a method, a device, a storage medium and a processor for calculating the temperature of a cable metal sleeve, which at least solve the technical problem that the temperature of the cable through-wall metal sleeve cannot be calculated.

According to an aspect of an embodiment of the present invention, there is provided a method of calculating a temperature of a metal sleeve of a cable, including: collecting the current of the cable and the conductivity of the cable core; acquiring sleeve parameters of a metal sleeve, wherein the metal sleeve is sleeved outside a cable, and the sleeve parameters at least comprise: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve; determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for representing the temperature value of the metal sleeve and the calculation relation among the cable current, the cable core conductivity, the metal sleeve magnetic permeability and the metal sleeve slit width; and determining the temperature value of the metal sleeve based on the cable current, the cable core conductivity, the metal sleeve magnetic conductivity, the metal sleeve slotting width and the temperature calculation formula of the metal sleeve.

Optionally, the method further comprises: acquiring a first preset relation between the cable current and the temperature value of the metal sleeve; acquiring a second preset relation between the conductivity of the cable core and the temperature value of the metal sleeve; acquiring a third preset relation between the magnetic conductivity of the metal sleeve and the temperature value of the metal sleeve; acquiring a fourth preset relation between the slotting width of the metal sleeve and the temperature value of the metal sleeve; and determining a temperature calculation formula of the metal sleeve based on the first preset relation, the second preset relation, the third preset relation and the fourth preset relation.

Optionally, the temperature calculation formula of the metal sleeve includes: when the conductivity is less than or equal to 1e6, T is 0.0512e⁰.^0015I-0.035Wσ^0.144(4.1lnμ_r+20.81)-20+T_ref(ii) a When the conductivity is >1e6,wherein T is the calculated temperature value of the metal sleeve in unit centigrade; t is_refThe starting temperature of the metal sleeve is in centigrade; w is the slotting width of the metal sleeve in mm; mu.s_rThe magnetic permeability of the metal sleeve is 1; sigma is the conductivity of the cable core and is in unit of s/m; i is the cable current in a.

Optionally, after determining the temperature value of the metal sleeve, the method further comprises: judging whether the temperature value of the metal sleeve is higher than a preset temperature threshold value or not; under the condition that the temperature value of the metal sleeve is determined to be higher than the preset temperature threshold, judging whether the slotting width of the metal sleeve is higher than a preset width threshold or not; generating prompt information under the condition that the metal sleeve slotting width is determined to be higher than the preset width threshold value, wherein the prompt information represents that the temperature value of the metal sleeve is reduced by increasing the metal sleeve slotting width.

According to another aspect of the embodiments of the present invention, there is also provided an apparatus for calculating a temperature of a metal sleeve of a cable, including: the acquisition unit is used for acquiring the current of the cable and the conductivity of the cable core; the acquisition unit is used for acquiring sleeve parameters of a metal sleeve, wherein the metal sleeve is sleeved on the outer side of the cable, and the sleeve parameters at least comprise: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve; the first determining unit is used for determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for representing the temperature value of the metal sleeve and the calculation relation among the cable current, the cable core conductivity, the metal sleeve magnetic permeability and the metal sleeve slotting width; and the second determination unit is used for determining the temperature value of the metal sleeve based on the cable current, the cable core conductivity, the metal sleeve magnetic conductivity, the metal sleeve slotting width and the temperature calculation formula of the metal sleeve.

Optionally, the apparatus further comprises: the first acquisition module is used for acquiring a first preset relation between the cable current and the temperature value of the metal sleeve; the second acquisition module is used for acquiring a second preset relation between the cable core conductivity and the temperature value of the metal sleeve; the third acquisition module is used for acquiring a third preset relation between the magnetic permeability of the metal sleeve and the temperature value of the metal sleeve; the fourth obtaining module is used for obtaining a fourth preset relation between the metal sleeve seam width and the temperature value of the metal sleeve; and the determining module is used for determining a temperature calculation formula of the metal sleeve based on the first preset relation, the second preset relation, the third preset relation and the fourth preset relation.

Optionally, the temperature calculation formula of the metal sleeve includes: when the conductivity is less than or equal to 1e6, T is 0.0512e^{0.0015i -0.035W}σ^0.144(4.1lnμ_r+20.81)-20+T_ref(ii) a When the conductivity is >1e6,wherein T is the calculated temperature value of the metal sleeve in unit centigrade; t is_refThe starting temperature of the metal sleeve is in centigrade; w is the slotting width of the metal sleeve in mm; mu.s_rThe magnetic permeability of the metal sleeve is 1; sigma is the conductivity of the cable core and is in unit of s/m; i is the cable current in a.

Optionally, the apparatus further comprises: the first judgment unit is used for judging whether the temperature value of the metal sleeve is higher than a preset temperature threshold value or not after the temperature value of the metal sleeve is determined; the second judging unit is used for judging whether the slotting width of the metal sleeve is higher than a preset width threshold value or not under the condition that the temperature value of the metal sleeve is determined to be higher than the preset temperature threshold value; and the prompting unit is used for generating prompting information under the condition that the metal sleeve slotting width is determined to be higher than the preset width threshold, wherein the prompting information indicates that the temperature value of the metal sleeve is reduced by increasing the metal sleeve slotting width.

According to another aspect of the embodiment of the present invention, there is also provided a storage medium, where the storage medium includes a stored program, and when the program runs, the apparatus on which the storage medium is located is controlled to execute the method for calculating the temperature of the metal sleeve of the cable described above.

According to yet another aspect of the embodiments of the present invention, there is further provided a processor for executing a program, wherein the program executes the method for calculating the temperature of the metal sleeve of the cable described above.

In the embodiment of the invention, the current of the cable and the conductivity of the cable core are collected; acquiring the sleeve parameters of the metal sleeve, wherein the metal sleeve is sleeved outside the cable, and the sleeve parameters at least comprise: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve; determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for expressing the temperature value of the metal sleeve and the calculation relation among the cable current, the cable core conductivity, the metal sleeve magnetic conductivity and the metal sleeve slotting width; the temperature value of the metal sleeve is determined based on a cable current, the cable core conductivity, the metal sleeve magnetic conductivity, the metal sleeve seam width and the metal sleeve temperature calculation formula, so that the technical effect of numerical calculation of the metal sleeve temperature value is achieved based on the metal sleeve temperature calculation formula, and the technical problem that the temperature of a cable through-wall metal sleeve cannot be calculated is solved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a flow chart of a method of calculating a cable metal sleeve temperature according to an embodiment of the invention;

FIG. 2 is a schematic of the temperature profile of a 110kV "Cable-Metal Sleeve" system;

FIG. 3 is a graph showing the temperature of the center of the metal sleeve as a function of the current of the cable;

FIG. 4 is a graph of the temperature at the center of a metallic sleeve versus the permeability of the material of the metallic sleeve;

FIG. 5 is a graph of metal sleeve core temperature versus slot width;

FIG. 6 is a schematic diagram of the curve of the center temperature of the metal sleeve with the conductivity of the cable core when the conductivity is less than or equal to 1e 6;

FIG. 7 is a graphical representation of the temperature at the center of the metal sleeve as a function of the conductivity of the cable core for conductivities >1e 6;

fig. 8 is a schematic view of an apparatus for calculating the temperature of a metal jacket of a cable according to an embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In accordance with an embodiment of the present invention, there is provided an embodiment of a method of calculating a temperature of a metal sheath of a cable, it being noted that the steps illustrated in the flowchart of the drawings may be performed in a computer system such as a set of computer-executable instructions and that, although a logical order is illustrated in the flowchart, in some cases the steps illustrated or described may be performed in an order different than presented herein.

Fig. 1 is a flow chart of a method of calculating a temperature of a metal jacket of a cable according to an embodiment of the present invention, as shown in fig. 1, the method comprising the steps of:

step S102, collecting cable current and cable core conductivity;

step S104, obtaining sleeve parameters of a metal sleeve, wherein the metal sleeve is sleeved outside the cable, and the sleeve parameters at least comprise: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve;

step S106, determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for expressing the temperature value of the metal sleeve and the calculation relation of the cable current, the cable core conductivity, the metal sleeve magnetic conductivity and the metal sleeve seam width;

and S108, determining a temperature value of the metal sleeve based on the cable current, the cable core conductivity, the metal sleeve magnetic conductivity, the metal sleeve slotting width and a metal sleeve temperature calculation formula.

In the embodiment of the invention, the current of the cable and the conductivity of the cable core are collected; acquiring the sleeve parameters of the metal sleeve, wherein the metal sleeve is sleeved outside the cable, and the sleeve parameters at least comprise: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve; determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for expressing the temperature value of the metal sleeve and the calculation relation of the cable current, the cable core conductivity, the metal sleeve magnetic conductivity and the metal sleeve slotting width; the temperature value of the metal sleeve is determined based on the cable current, the cable core conductivity, the metal sleeve magnetic conductivity, the metal sleeve slotting width and the metal sleeve temperature calculation formula, so that the technical effect of numerical calculation of the metal sleeve temperature value is achieved based on the metal sleeve temperature calculation formula, and the technical problem that the cable through-wall metal sleeve temperature cannot be calculated is solved.

It should be noted that the method for calculating the temperature of the metal sleeve of the cable shown in fig. 1 can be operated in a computer, and the computer can be connected with a current collecting device, collect the current of the cable and the conductivity of the cable core by the current collecting device, and provide the collected current of the cable and the conductivity of the cable core to the computer in the form of numerical values.

Optionally, the cable current and the cable core conductivity can also be manually input by a user on a computer.

It should be noted that the sleeve parameters of the metal sleeve may be manually input by a user on a computer, or may be called by the computer in a circuit design file where the cable is located.

The magnetic permeability of the metal sleeve is the relative magnetic permeability of the material of the metal sleeve.

As an alternative embodiment, the method further comprises: acquiring a first preset relation between the cable current and the temperature value of the metal sleeve; acquiring a second preset relation between the cable core conductivity and the temperature value of the metal sleeve; acquiring a third preset relation between the magnetic conductivity of the metal sleeve and the temperature value of the metal sleeve; acquiring a fourth preset relation between the slotting width of the metal sleeve and the temperature value of the metal sleeve; and determining a temperature calculation formula of the metal sleeve based on the first preset relation, the second preset relation, the third preset relation and the fourth preset relation.

In the above embodiment of the present invention, based on the first preset relationship, the second preset relationship, the third preset relationship, and the fourth preset relationship, the influence of the cable current, the cable core conductivity, the metal sleeve magnetic permeability, and the metal sleeve seam width on the temperature value of the metal sleeve can be determined, and further based on the influence of the cable current, the cable core conductivity, the metal sleeve magnetic permeability, and the metal sleeve seam width on the temperature value of the metal sleeve, the temperature calculation formula of the metal sleeve can be determined.

As an alternative embodiment, the temperature calculation formula of the metal sleeve includes: when the conductivity is less than or equal to 1e6, T is 0.0512e^{0.0015I-0.035W}σ^0.144(4.1lnμ_r+20.81)-20+T_ref(ii) a When the conductivity is >1e6,wherein T is the calculated temperature value of the metal sleeve in unit centigrade; t is_refThe initial temperature of the metal sleeve is in centigrade; w is the slotting width of the metal sleeve in mm; mu.s_rThe magnetic conductivity of the metal sleeve is 1; sigma is the cable core conductivity in s/m; i is the cable current in a.

It should be noted that, in the process of calculating the temperature value of the metal sleeve based on the formula for calculating the temperature of the metal sleeve, the temperature value calculated by the formula is the temperature value raised by the metal sleeve, and the actual temperature value of the metal sleeve is the sum of the calculated temperature value and the current ambient temperature.

As an alternative embodiment, after determining the temperature value of the metal sleeve, the method further comprises: judging whether the temperature value of the metal sleeve is higher than a preset temperature threshold value or not; under the condition that the temperature value of the metal sleeve is higher than a preset temperature threshold value, judging whether the slotting width of the metal sleeve is higher than a preset width threshold value or not; and generating prompt information under the condition that the metal sleeve slotting width is determined to be higher than a preset width threshold value, wherein the prompt information indicates that the temperature value of the metal sleeve is reduced by increasing the metal sleeve slotting width.

In the above embodiment of the present invention, when the temperature value of the metal sleeve is higher than the preset temperature threshold, the temperature value of the metal sleeve can be reduced by increasing the slit width of the metal sleeve, but when the slit width of the metal sleeve reaches the preset width threshold, the increase of the temperature rise suppression effect is not obvious, and the temperature value of the metal sleeve cannot be reduced by increasing the slit width of the metal sleeve.

The invention also provides a preferred embodiment, which provides a method for calculating the temperature of the cable through-wall metal sleeve.

According to the technical scheme provided by the invention, through theoretical analysis, three-dimensional modeling and multi-physical-field simulation of a cable-metal sleeve system, main factors and influence rules of the main factors influencing the temperature of the metal sleeve are obtained, and a formula for calculating the temperature of the metal sleeve is summarized. The formula can be used for conveniently calculating the temperature of the metal sleeve under different working conditions and can be used for designing the slotting size of the metal sleeve. The method solves the problems of multiple influence factors of a temperature field of a cable-metal sleeve system, complex calculation and no basis for the design of the slotting size, and provides a technical means for accurately evaluating the temperature rise of the metal sleeve and optimizing the slotting size.

It should be noted that the heating of the metal sleeve is a result of the coupling and coaction of the magnetic field and the temperature field, the cable core of the cable generates heat due to the passing of current, and an alternating magnetic field is generated at the same time, so that eddy current is generated in the metal sleeve to heat and raise the temperature of the wall-penetrating metal sleeve, and the two types of heat generation are heat sources of the temperature field. The cable and the metal sleeve are tightly connected through filling layers such as insulating materials, and heat is transferred among the layers through solid heat transfer. The temperature change can cause the resistivity of the cable core to change, thereby influencing the heating power of a cable-metal sleeve system, namely the heat source power of a temperature field. The heat dissipation of the metal sleeve has two ways, namely, solid heat transfer is carried out through a wall body tightly connected with the metal sleeve; and then the surface of the cable, the metal sleeve, the filling layer and the wall body and air are used for carrying out fluid and solid heat transfer.

Since the main cause of heat generation of the metal sleeve is eddy current loss formed in the metal sleeve by current passing through the cable, the current-carrying capacity of the cable and the relative permeability of the metal sleeve material are main factors affecting heat generation. In addition, factors such as cable size, cable arrangement, ambient temperature, heat dissipation conditions, and wall reinforcement distribution also have an effect on heat generation. Because the temperature calculation of the cable-metal sleeve system relates to three-dimensional modeling and multi-physical-field coupling simulation, a theoretical calculation formula is difficult to obtain.

Fig. 2 is a schematic diagram of temperature distribution of a 110kV "cable-metal sleeve" system, and as shown in fig. 2, in finite element simulation software COMSOL, a three-dimensional simulation model of a "cable-metal sleeve" is established according to actual size and material characteristics, and initial conditions such as current-carrying capacity and ambient temperature are input, so that system temperature field distribution under various working conditions can be obtained, and an influence rule of each factor on the temperature of the metal sleeve can also be obtained.

Fig. 3 is a schematic diagram of a change curve of the central temperature of the metal sleeve with the current of the cable, and as shown in fig. 3, a linear regression equation of the change curve of the central temperature of the metal sleeve with the current is as follows: 8.4805e^0.0015xThe correlation index of the linear regression equation is: r²＝0.9994。

It should be noted that the magnetic conductivity of the metal sleeve material is a main factor affecting the temperature rise of the metal sleeve, and the induced current and eddy current loss of the material with higher magnetic conductivity are both large, so that the temperature rise problem is more serious.

Fig. 4 is a schematic diagram of a change curve of the central temperature of the metal sleeve with the magnetic permeability of the material of the relative metal sleeve, and as shown in fig. 4, a linear regression equation of the change curve of the central temperature of the metal sleeve with the relative magnetic permeability is as follows: y is 4.1ln (μ r) +20.81, and the correlation index of the linear regression equation is: r²＝0.9567。

It should be noted that, slotting on the metal sleeve can reduce equivalent magnetic permeability, reduce eddy current loss, and achieve the effect of reducing temperature rise, but the cooling effect does not increase linearly with the increase of the size of the slotting.

Fig. 5 is a schematic diagram of a curve of the metal sleeve center temperature along with the slit width, and as shown in fig. 5, a linear regression equation of the curve of the metal sleeve center temperature along with the slit width is as follows: 52.476e^-0.035WThe correlation index of the linear regression equation is: r2 ═ 0.9196.It can be seen that the temperature of the metal sleeve can be reduced by the slotting, but the increase of the temperature rise inhibiting effect is not obvious after the width of the slotting is larger than 6 mm.

Fig. 6 is a schematic diagram of a curve of the center temperature of the metal sleeve along with the conductivity of the cable core when the conductivity is less than or equal to 1e6, and as shown in fig. 6, a linear regression equation of the curve of the center temperature of the metal sleeve along with the conductivity is as follows: 13.475 σ^0.1444The correlation index of the linear regression equation is: r²＝0.9859。

FIG. 7 is the conductivity>1e6, a schematic diagram of a curve of the metal sleeve center temperature along with the cable core conductivity, as shown in fig. 7, a linear regression equation of the curve of the metal sleeve center temperature along with the conductivity is: y 103.12e^-8E-08σThe correlation index of the linear regression equation is: r²＝0.9909。

Through the above analysis of fig. 2 to fig. 7, after determining the main factors (such as current-carrying capacity, i.e. cable current, cable core conductivity, relative permeability of the metal sleeve material, slot width, cable core conductivity, and ambient temperature), the secondary factors (cable size, cable arrangement, heat dissipation conditions, and wall reinforcement distribution), and their influence rules, which affect the "cable-metal sleeve" temperature, the metal sleeve temperature can be expressed as a function using the above factors as independent variables, and the temperature calculation formula of the metal sleeve can be obtained by combining theoretical analysis and curve fitting:

optionally, the temperature calculation formula of the metal sleeve includes: when the conductivity is less than or equal to 1e6, T is 0.0512e^{0.0015I -0.035W}σ^0.144(4.1lnμ_r+20.81)-20+T_ref(ii) a When the conductivity is >1e6,wherein T is the calculated temperature value of the metal sleeve in unit centigrade; t is_refThe starting temperature of the metal sleeve is in centigrade; w is the slotting width of the metal sleeve in mm; mu.s_rThe magnetic permeability of the metal sleeve is 1; sigma is the conductivity of the cable core and is in unit of s/m; l is the cable current in units A.

In the above embodiment of the present invention, the temperature calculation formula based on the metal sleeve summarizes the influence of the above factors, and through simulation verification, the formula can be used for temperature calculation and slit width design of various working conditions of a 110kV "cable-metal sleeve".

The technical scheme provided by the invention is suitable for calculating the temperature of the metal sleeve of the 110kV cable, most cables below 110kV are in a three-phase common structure, and the three-phase common structure can reduce the magnetic flux density in the metal sleeve so as to reduce eddy current, so that the heating problem of the metal sleeve is not serious.

According to the technical scheme provided by the invention, in the process of calculating the temperature of the sleeve, the current-carrying capacity of the cable, the magnetic conductivity of the metal sleeve, the ambient temperature and the size of the seam (0 mm is taken without the seam) can be substituted into a temperature calculation formula of the metal sleeve, and then the temperature of the metal sleeve can be obtained. If the temperature of the metal sleeve exceeds a limit value, a method of slotting on the metal sleeve can be adopted to reduce the temperature. The slot size is adjusted in the formula, and temperature values under different slot sizes can be obtained.

Table 1 shows the comparison of the simulation results and the formula calculation results under several conditions.

The technical scheme provided by the invention is used for solving the heating problem of the power cable wall-penetrating metal sleeve, summarizing main factors and influence rules of the temperature of the metal sleeve on the basis of theoretical analysis and three-dimensional multi-physical-field simulation, and providing a temperature calculation formula of the metal sleeve, wherein the formula comprehensively considers the influences of the material characteristics of the cable and the metal sleeve, the current-carrying capacity of the cable, the environment temperature and the slotting size of the metal sleeve on the temperature of the metal sleeve, and can be used for evaluating the temperature rise of the metal sleeve and optimizing the slotting size in engineering.

According to yet another embodiment of the present invention, there is also provided a storage medium including a stored program, wherein the program performs any one of the above methods when executed.

According to yet another embodiment of the present invention, there is also provided a processor for executing a program, wherein the program executes to perform the method of any one of the above.

According to an embodiment of the present invention, an embodiment of an apparatus for calculating a temperature of a metal sleeve of a cable is further provided, and it should be noted that the apparatus for calculating a temperature of a metal sleeve of a cable may be used to perform the method for calculating a temperature of a metal sleeve of a cable in the embodiment of the present invention, and the method for calculating a temperature of a metal sleeve of a cable in the embodiment of the present invention may be performed in the apparatus for calculating a temperature of a metal sleeve of a cable.

Fig. 8 is a schematic view of an apparatus for calculating a temperature of a metal jacket of a cable according to an embodiment of the present invention, as shown in fig. 8, the apparatus may include: the acquisition unit 82 is used for acquiring the current of the cable and the conductivity of the cable core; the obtaining unit 84 is configured to obtain a sleeve parameter of a metal sleeve, where the metal sleeve is sleeved outside the cable, and the sleeve parameter at least includes: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve; the first determining unit 86 is used for determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for representing the temperature value of the metal sleeve and the calculation relation between the temperature value and the cable current, the cable core conductivity, the metal sleeve magnetic permeability and the metal sleeve slotting width; and the second determining unit 88 is used for determining the temperature value of the metal sleeve based on the cable current, the cable core conductivity, the metal sleeve magnetic conductivity, the metal sleeve slotting width and the temperature calculation formula.

It should be noted that the acquiring unit 82 in this embodiment may be configured to execute step S102 in this embodiment, the obtaining unit 84 in this embodiment may be configured to execute step S104 in this embodiment, the first determining unit 86 in this embodiment may be configured to execute step S106 in this embodiment, and the second determining unit 88 in this embodiment may be configured to execute step S108 in this embodiment. The above units are the same as the examples and application scenarios realized by the corresponding steps, but are not limited to the disclosure of the above embodiments.

In the embodiment of the invention, the current of the cable and the conductivity of the cable core are collected; acquiring the sleeve parameters of the metal sleeve, wherein the metal sleeve is sleeved outside the cable, and the sleeve parameters at least comprise: the magnetic conductivity of the metal sleeve and the slotting width of the metal sleeve; determining a temperature calculation formula of the metal sleeve based on the cable core conductivity, wherein the temperature calculation formula of the metal sleeve is used for expressing the temperature value of the metal sleeve and the calculation relation of the cable current, the cable core conductivity, the metal sleeve magnetic conductivity and the metal sleeve slotting width; the temperature value of the metal sleeve is determined based on a cable current, cable core conductivity, metal sleeve permeability, metal sleeve seam width and a metal sleeve temperature calculation formula, so that the technical effect of numerical calculation of the metal sleeve temperature value is achieved based on the metal sleeve temperature calculation formula, and the technical problem that the temperature of a cable through-wall metal sleeve cannot be calculated is solved.

As an alternative embodiment, the apparatus further comprises: the first acquisition module is used for acquiring a first preset relation between the cable current and the temperature value of the metal sleeve; the second acquisition module is used for acquiring a second preset relation between the cable core conductivity and the temperature value of the metal sleeve; the third acquisition module is used for acquiring a third preset relation between the magnetic permeability of the metal sleeve and the temperature value of the metal sleeve; the fourth obtaining module is used for obtaining a fourth preset relation between the metal sleeve seam width and the temperature value of the metal sleeve; and the determining module is used for determining a temperature calculation formula of the metal sleeve based on the first preset relation, the second preset relation, the third preset relation and the fourth preset relation.

As an alternative embodiment, the temperature calculation formula of the metal sleeve includes: when the conductivity is less than or equal to 1e6, T is 0.0512e^{0.0015I-0.035W}σ^0.144(4.1lnμ_r+20.81)-20+T_ref(ii) a When the conductivity is >1e6,wherein T is the calculated temperature value of the metal sleeve in units of centigradeDegree; t is_refThe starting temperature of the metal sleeve is in centigrade; w is the slotting width of the metal sleeve in mm; mu.s_rThe magnetic permeability of the metal sleeve is 1; sigma is the conductivity of the cable core and is in unit of s/m; i is the cable current in a.

As an alternative embodiment, the apparatus further comprises: the first judgment unit is used for judging whether the temperature value of the metal sleeve is higher than a preset temperature threshold value or not after the temperature value of the metal sleeve is determined; the second judging unit is used for judging whether the slotting width of the metal sleeve is higher than a preset width threshold value or not under the condition that the temperature value of the metal sleeve is higher than the preset temperature threshold value; and the prompting unit is used for generating prompting information under the condition that the slotting width of the metal sleeve is determined to be higher than a preset width threshold, wherein the prompting information indicates that the temperature value of the metal sleeve is reduced by increasing the slotting width of the metal sleeve.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.