Cable temperature rise simulation method, device, equipment and medium

Abstract

The embodiment of the invention relates to a cable temperature rise simulation method and device, equipment and a medium. The method comprises the steps that a finite element simulation model is established according to the structure and laying conditions of a cable; the finite element simulation model comprises a cable simulation model and a duct bank simulation model; determining boundary conditions and material parameters of the finite element simulation model; the boundary conditions comprise the boundary conditions of the cable and the calandria and the boundary conditions of the calandria and external soil, and the material parameters comprise the heat conductivity coefficient and the specific heat capacity; setting a load current of the cable simulation model and a change function relationship between a heat conductivity coefficient of soil and the soil humidity; and performing finite element thermal simulation on the finite element simulation model based on the heat conduction equation to obtain a steady-state value reached by the cable temperature under different soil humidity conditions and time consumed for reaching the steady-state value. According to the embodiment of the invention, thermal simulation is carried out on the cable temperature rise in combination with the cable laying condition and the soil humidity, and the influence of the soil humidity better fitting the actual working condition on the cable temperature rise is obtained.

Description

Background Art

[0002] With the operating conditions of power cables becoming increasingly variable and the laying environment becoming more complex, there are more and more factors affecting the cable temperature rise. Among them, soil humidity not only affects the safety of underground cable laying, but also has an impact on its own heat conduction performance, thereby affecting cable heat dissipation. Soil with appropriate humidity usually has relatively ideal heat conduction performance, and the heat generated during cable operation can be more effectively dissipated through the soil, which helps to maintain the working temperature of the cable within a relatively stable range.

[0003] In the prior art, most thermal simulations of cable temperature rise are carried out from the aspects of cable self-heat generation and heat conduction, and it is only disclosed that the heat conduction performance of the soil affects cable heat dissipation, but the thermal simulation of cable temperature rise is not carried out by combining the cable laying conditions and soil humidity to obtain the influence of soil humidity closer to the actual working conditions on cable temperature rise.

[0004] Therefore, it is necessary to provide a new technical solution to improve one or more problems existing in the above solution.

[0005] It should be noted that the information disclosed in the above background art section is only used to strengthen the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0006] The purpose of the embodiments of the present disclosure is to provide a cable temperature rise simulation method, device, equipment and medium, which combine the cable laying conditions and soil humidity to perform a thermal simulation of the cable temperature rise, so as to obtain the influence of soil humidity closer to the actual working conditions on the cable temperature rise.

[0007] According to the first aspect of the embodiments of the present disclosure, a cable temperature rise simulation method is provided, including:

[0008] Establish a finite element simulation model according to the structure and laying conditions of the cable; wherein, the finite element simulation model includes a cable simulation model and a pipe rack simulation model;

[0009] Determine the boundary conditions and material parameters of the finite element simulation model; wherein, the boundary conditions include the boundary conditions between the cable and the pipe rack and the boundary conditions between the pipe rack and the external soil, and the material parameters include the thermal conductivity and specific heat capacity;

[0010] Set the load current of the cable simulation model and the variation function relationship between the thermal conductivity of the external soil and soil humidity;

[0011] Perform a finite element thermal simulation on the finite element simulation model based on the heat conduction equation to obtain the steady-state values of the cable temperature under different soil humidity conditions and the time taken to reach the steady-state values.

[0012] In an exemplary embodiment of the present disclosure, the cable simulation model includes a conductor layer, an insulation layer, and a sheath layer. The cable temperature rise simulation method further includes:

[0013] Determine the power loss of the cable simulation model; wherein, the power loss of the cable simulation model includes the resistance loss of the conductor layer and the dielectric loss of the insulation layer.

[0014] In an exemplary embodiment of the present disclosure, the resistance loss of the conductor layer is:

[0015] W c = I 2 *(1 + y s + y p )(1)

[0016] wherein, W represents the resistance loss of the conductor layer per unit length, I represents the load current, y s represents the skin effect factor, and y p represents the proximity effect factor of the conductor layer;

[0017] The dielectric loss of the insulation layer is:

[0018]

[0019] wherein, W d represents the resistance loss of the insulation layer per unit length, w takes the value of 2πf, f = 50 Hz, c represents the capacitance, U0 represents the rated phase voltage, and tanδ represents the dielectric loss factor.

[0020] In an exemplary embodiment of the present disclosure, the boundary conditions further include the heat transfer boundary condition between the conductor layer and the insulation layer and the heat transfer boundary condition between the insulation layer and the sheath layer.

[0021] In an exemplary embodiment of the present disclosure, the heat conduction equation of the conductor layer in the cable simulation model is:

[0022]

[0023] wherein, T represents the temperature at the point (x, y), q v represents the heat generation rate per unit volume of the heat source; λ represents the thermal conductivity of the medium;

[0024] The heat conduction equations of the insulation layer and the sheath layer in the cable simulation model are:

[0025]

[0026] wherein, T represents the temperature at the point (x, y).

[0027] In an exemplary embodiment of the present disclosure, the functional relationship between the thermal conductivity of the external soil and the change in soil moisture is:

[0028] k = 0.10804h + 0.5656(5)

[0029] where k represents the thermal conductivity of the external soil and h represents the soil moisture.

[0030] In an exemplary embodiment of the present disclosure, before performing the finite element thermal simulation on the finite element simulation model based on the heat conduction equation, it further includes:

[0031] Performing mesh division on the finite element simulation model; wherein, the mesh density of the cable simulation model is less than the mesh density of the pipe bundle simulation model.

[0032] According to a second aspect of the embodiments of the present disclosure, there is provided a cable temperature rise simulation device, including:

[0033] A model establishment module, configured to establish a finite element simulation model according to the structure and laying conditions of the cable; wherein, the finite element simulation model includes a cable simulation model and a pipe bundle simulation model;

[0034] A thermal simulation parameter determination module, configured to determine the boundary conditions and material parameters of the finite element simulation model; wherein, the boundary conditions include the boundary conditions between the cable and the pipe bundle and the boundary conditions between the pipe bundle and the external soil, and the material parameters include thermal conductivity and specific heat capacity;

[0035] A thermal simulation operating condition setting module, configured to set the load current of the cable simulation model and the functional relationship between the thermal conductivity of the external soil and the change in soil moisture;

[0036] A thermal simulation solution module, configured to perform finite element thermal simulation on the finite element simulation model based on the heat conduction equation to obtain the steady-state values of the cable temperature under different soil moisture conditions and the time taken to reach the steady-state values.

[0037] According to a third aspect of the embodiments of the present disclosure, there is provided an electronic device, the electronic device includes:

[0038] A processor; and

[0039] A memory, configured to store executable instructions of the processor;

[0040] wherein, the processor is configured to execute the steps of the cable temperature rise simulation method as described in any one of the above by executing the executable instructions.

[0041] According to a fourth aspect of the embodiments of the present disclosure, there is provided a computer storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the cable temperature rise simulation method described in any one of the above is implemented.

[0042] The technical solutions provided by the present disclosure may include the following beneficial effects:

[0043] In the embodiments of the present disclosure, a finite element simulation model is established according to the structure and laying conditions of the cable. For the finite element simulation model, the boundary conditions and material parameters of the finite element simulation model are determined, and the load current of the cable simulation model and the variation function relationship between the thermal conductivity of the external soil and the soil humidity are set, so that in the subsequent finite element thermal simulation, the steady-state value of the cable temperature under the corresponding soil humidity condition and the time taken to reach the steady-state value are simulated and calculated in combination with the laying conditions of the cable, so as to obtain the influence of the soil humidity closer to the actual working conditions on the cable temperature rise.

[0044] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0046] Figure 1 A flowchart showing the steps of the cable temperature rise simulation method in an exemplary embodiment of the present disclosure;

[0047] Figure 2 A schematic cross-sectional view showing the mesh division of the simulation model in an exemplary embodiment of the present disclosure;

[0048] Figure 3 A graph showing the temperature rise curves of the conductor layer and the sheath layer under different soil humidity conditions in an exemplary embodiment of the present disclosure;

[0049] Figure 4 A schematic diagram showing the cable operation simulation under the laying condition of 2×2 rows of pipes in an exemplary embodiment of the present disclosure;

[0050] Figure 5 A schematic structural diagram showing the cable temperature rise simulation device in an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0051] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more complete and comprehensive, and will fully convey the concept of the example embodiments to those skilled in the art. The features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0052] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus repeated descriptions thereof will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0053] In this example embodiment, a cable temperature rise simulation method is first provided. Referring to Figure 1 as shown, the method may include the following steps:

[0054] Step S101: Establish a finite element simulation model according to the structure and laying conditions of the cable; wherein, the finite element simulation model includes a cable simulation model and a pipe rack simulation model;

[0055] Step S102: Determine the boundary conditions and material parameters of the finite element simulation model; wherein, the boundary conditions include the boundary conditions between the cable and the pipe rack and the boundary conditions between the pipe rack and the external soil, and the material parameters include the thermal conductivity and specific heat capacity;

[0056] Step S103: Set the load current of the cable simulation model and the variation function relationship between the thermal conductivity of the external soil and the soil humidity;

[0057] Step S104: Perform finite element thermal simulation on the finite element simulation model based on the heat conduction equation to obtain the steady-state values of the cable temperature under different soil humidity conditions and the time taken to reach the steady-state values.

[0058] In the embodiments of the present disclosure, a finite element simulation model is established according to the structure and laying conditions of the cable. For the finite element simulation model, the boundary conditions and material parameters of the finite element simulation model are determined, and the load current of the cable simulation model and the variation function relationship between the thermal conductivity of the external soil and the soil humidity are set, so as to, in subsequent finite element thermal simulation, simulate and calculate the steady-state values of the cable temperature under the corresponding soil humidity conditions in combination with the laying conditions of the cable, as well as the time taken to reach the steady-state values, in order to obtain the influence of soil humidity on the cable temperature rise under more actual working conditions.

[0059] Next, each step of the above method in this exemplary embodiment will be described in more detail.

[0060] In one embodiment, in step S101, the cable simulation model includes a conductor layer, an insulating layer, and a sheath layer. Among them, the materials, nominal thicknesses, and outer diameter dimensions of the cable and the pipe are specifically shown in Table 1 below:

[0061] Table 1 Size parameters of the cable and the pipe

[0062] Structure Material Nominal Thickness / mm Outer Diameter / mm Conductor Layer Copper 61.0±1.0 Insulation Layer Crosslinked Polyethylene 29.5 125.0±1.5 Sheath Layer Aluminum 3.3 153.0 Duct Chlorinated Polyvinyl Chloride 16～24 300

[0063] Exemplarily, in terms of the structural position relationship, the cable simulation model is located inside the pipe simulation model. For the boundary conditions between the cable and the pipe in step S102, both the outermost sheath layer of the cable and the inner wall of the pipe are set as non-slip wall surfaces, that is, it is assumed that the air flow velocity on the outer wall of the sheath layer and the inner wall of the pipe is zero, which is used as the boundary condition of the fluid field of the enclosed air layer inside the pipe. This setting ensures that the model can accurately reflect the interaction between the fluid and the solid wall surface during the simulation process.

[0064] It should be noted that for the air gap between the cable and the pipe, and it is assumed that the air existing inside the pipe is enclosed air and an incompressible fluid, then under this natural convection condition, due to the temperature difference between the cable surface and the air, there is still heat conduction. In this case, the heat exchange boundary conditions between the cable surface, the inner wall of the pipe, and the air can be regarded as the third type of boundary conditions.

[0065] In one embodiment, it is assumed that the pipe is laid in a soil environment, and the initial temperature of the soil is 20 °C. Considering that during the operation of the cable, the heat generated by the cable conductor layer will be transferred to the pipe, and the pipe will then continuously exchange heat with the external soil. Therefore, the boundary conditions between the pipe and the external soil in step S102 can be regarded as satisfying the second type of boundary conditions, and its control equation is:

[0066]

[0067] Among them, Γ represents the integration boundary, represents the heat flux density at a point on the boundary Γ, λ represents the thermal conductivity of the medium, n represents the outer normal direction of the boundary, and q represents the heat flux density.

[0068] It should be noted that in order to more accurately simulate and analyze the influence of soil moisture on the cable temperature rise, for the soil above the pipe laid in the top layer, considering that the upper surface of this soil is exposed to the ground surface, its boundary conditions with the external air environment can be regarded as the third type of boundary conditions, and its control equation is:

[0069]

[0070] Among them, Γ represents the integration boundary, represents the heat flux density on the boundary Γ, λ represents the thermal conductivity of the medium, and (T - T f )| Γ represents the temperature value of a point on the boundary Γ, T represents the boundary temperature, and T f represents the fluid temperature, and h represents the convective heat transfer coefficient of the surface air.

[0071] In one embodiment, the cable simulation model includes a conductor layer, an insulating layer, and a sheath layer. The boundary conditions in step S102 further include the heat transfer boundary conditions between the conductor layer and the insulating layer and the heat transfer boundary conditions between the insulating layer and the sheath layer.

[0072] Specifically, for the heat transfer boundary conditions between the conductor layer and the insulating layer and the heat transfer boundary conditions between the insulating layer and the sheath layer, considering that the outer surface of the conductor layer and the inner surface of the insulating layer are in a contact relationship, and the outer surface of the insulating layer and the inner surface of the sheath layer are in a contact relationship, therefore, the relationship between the conductor layer and the insulating layer and the relationship between the insulating layer and the sheath layer can both be regarded as heat conduction boundary relationships. According to Fourier's law, the heat conduction relationships between the conductor layer and the insulating layer and between the insulating layer and the sheath layer can be defined by the following formula:

[0073]

[0074] Among them, Φ represents the heat flowing through the flat plate, A represents the area of the flat plate; λ represents the thermal conductivity of the medium, represents the temperature change rate of a point on the flat plate in the x direction.

[0075] In step S102, the soil environment parameters and the material parameters of the cable and the pipe are specifically shown in Table 2 below:

[0076] Table 2 Material Parameters

[0077] Material Soil Conductor Layer Insulation Layer Sheath Layer Duct Thermal Conductivity / W / (m·K) 1 400 0.286 44.5 0.1667 Density / kg / m3 2020 8700 7850 7850 1450 Specific Heat Capacity / J / (kg·K) 2512 385 2510 475 1005

[0078] It should be noted that the cable simulation model in the above embodiment is a simplified model, which can effectively reduce the amount of calculation while not affecting the accuracy of the simulation calculation. Of course, in other embodiments, the cable simulation model may include a conductor layer, a conductor shielding layer, an insulating layer, an insulating shielding layer, a buffer layer, a metal sheath layer, and an outer sheath layer.

[0079] In one embodiment, in step S103, the load current of the cable simulation model is set to 1850A.

[0080] In one embodiment, the functional relationship between the thermal conductivity of the external soil and the change in soil moisture is:

[0081] k = 0.10804h + 0.5656(5)

[0082] Wherein, k represents the thermal conductivity of the external soil, and h represents the soil humidity.

[0083] It should be noted that the variation function relationship between the thermal conductivity of the above-mentioned external soil and the soil humidity can be obtained through the following method:

[0084] Collect the corresponding thermal conductivities under different soil humidity conditions, fit the collected thermal conductivities, and obtain the variation function relationship between the thermal conductivity of the soil and the soil humidity.

[0085] In one embodiment, before performing the finite element thermal simulation, the cable temperature rise simulation method further includes:

[0086] Determine the power loss of the cable simulation model; wherein, the power loss of the cable simulation model includes the resistance loss of the conductor layer and the dielectric loss of the insulation layer.

[0087] Specifically, the resistance loss of the conductor layer is:

[0088] W c = I 2 *(1 + y s + y p ) (1)

[0089] Wherein, W represents the resistance loss of the conductor layer per unit length; I represents the load current, y s represents the skin effect factor, and y p represents the proximity effect factor of the conductor layer;

[0090] The dielectric loss of the insulation layer is:

[0091]

[0092] Wherein, W d represents the resistance loss of the insulation layer per unit length, w takes the value of 2πf, f = 50Hz, c represents the capacitance, U0 represents the rated phase voltage, and tanδ represents the dielectric loss factor.

[0093] During the operation of the cable, while the conductor layer of the cable transfers heat outward as a heat source, there is also a certain resistance loss; similarly, as the insulation layer close to the conductor layer, the heat transferred per unit time is relatively large, and there is also a certain dielectric loss while transferring heat to the outer sheath layer. By considering the above-mentioned resistance loss of the conductor layer and the dielectric loss of the insulation layer, it is beneficial to more accurately simulate and calculate the steady-state value of the cable temperature under different soil humidity conditions and the time taken to reach the steady-state value.

[0094] In one embodiment, before performing finite element thermal simulation on the finite element simulation model based on the heat conduction equation, the method further includes:

[0095] The finite element simulation model is meshed, wherein the mesh density of the cable simulation model is smaller than the mesh density of the pipe simulation model, and such meshing design can effectively reduce the consumption of computing resources while ensuring the computing accuracy.

[0096] It should be noted that in the meshing step, it is necessary to perform multi-scale meshing on the cross-sections of the cable simulation model, the drainage pipe simulation model and the soil simulation model outside the drainage pipe.

[0097] Example, reference Figure 2 As shown in the figure, for the cable simulation model, a highly refined processing method is adopted to ensure that the physical characteristics of the key areas can be accurately captured and analyzed. For the simulation model of the pipe and the area around the pipe, relatively fine grid units are used. For the soil area far away from the cable, in order to effectively reduce the consumption of computing resources while ensuring the calculation accuracy, a coarse subdivision method is adopted. This multi-scale meshing strategy significantly reduces the total number of meshes in the model while ensuring the accuracy of the simulation calculation, thereby speeding up the calculation speed and shortening the simulation cycle.

[0098] In one embodiment, the heat conduction equation in step S104 includes the heat conduction equation of the conductor layer in the cable simulation model and the heat conduction equations of the insulation layer and the sheath layer. The heat conduction equation of the conductor layer in the cable simulation model is:

[0099]

[0100] Where T represents the temperature at point (x,y), q v represents the heat generation rate per unit volume of the heat source; λ represents the thermal conductivity of the medium;

[0101] The heat conduction equations for the insulation layer and the sheath layer in the cable simulation model are:

[0102]

[0103] Where T is the temperature at point (x,y).

[0104] It should be noted that, in the finite element thermal simulation calculation process in step S104, after constraining the load current of the cable, the conductor layer of the cable is used as a heat source, and its real-time heat generation can be calculated by the following formula:

[0105]

[0106] Where Q represents the heat generated by the conductor layer, in W / m3 , where \(I\) represents the current in the conductor layer, \(R\) represents the resistance of the conductor layer, \(S\) represents the cross-sectional area of the conductor layer, and \(L\) represents the length of the conductor layer.

[0107] It should also be noted that in order to reduce the computational workload of the finite element simulation model and improve the computational efficiency, the following simplifications are made during modeling: assume that the cable is infinitely long, do not consider the influence of axial heat transfer, equivalent the three-dimensional model to a two-dimensional model, and at the same time ignore the influence of the cable support; the conductor joule loss and dielectric loss are the main heat sources of the cable, and the influence of the metal sheath loss is ignored in the model; in the case of pipe laying, the natural convection velocity of the enclosed air domain in the pipe is relatively low, and the air in the trench can be considered as an incompressible fluid.

[0108] The results of the finite element thermal simulation of the finite element simulation model in step S104 are given below. For the condition of implementing 2×2 pipe laying and applying a load current of 1850 A to the cable, the cable temperature rise simulation results under the soil humidity of 0%, 5%, 10%, 15%, and 20% are calculated respectively, and the results are as shown in Table 3, Figure 3 and Figure 4 shown as follows:

[0109] Table 3 Cable temperature rise simulation results under different soil humidity conditions

[0110]

[0111] It can be seen from the above table that as the humidity increases, the steady-state value of the conductor layer temperature gradually decreases. This is because the increase in the thermal conductivity makes the heat of the cable conductor layer easier to transfer from the conductor layer to the sheath layer, thus reducing the steady-state value of the conductor layer temperature. Similarly, the steady-state value of the sheath layer temperature also decreases with the increase in humidity, which is consistent with the change in the temperature of the conductor layer, indicating that the heat is more effectively transferred from the conductor layer to the sheath layer and dissipated to the external soil environment.

[0112] By analyzing the time required for the cable temperature to reach the steady-state value, it can be found that as the humidity increases, the time required for the conductor layer temperature to reach the steady-state value gradually decreases. That is, when the humidity increases from 0% to 20%, the time decreases from 280 h to 90 h, a decrease of about 68%. This shows that the increase in humidity leads to a significant increase in the thermal conductivity and an enhancement of the heat transfer efficiency, so the temperature rise of the conductor layer can reach the steady state faster. In addition, it also shows that the increase in humidity will change the heat conduction path to a certain extent, making the heat distribution more uniform and further accelerating the temperature balance process.

[0113] T2 in the above table represents the time taken for the temperature of the conductor layer to reach 90°C. As the humidity increases, i.e., from 0% to 10%, T2 increases from 72 h to 157 h. This indicates that the increase in humidity delays the time for the temperature of the conductor layer to rise to 90°C. This is because the increase in humidity leads to an increase in the heat capacity of the material, and more heat is required to raise the temperature of the conductor layer to 90°C. At the same time, the increase in humidity may introduce a non-linear heat conduction effect, further delaying the temperature rise.

[0114] Based on the above analysis of the simulation results, it can be seen that the increase in soil humidity significantly increases the thermal conductivity, causing the steady-state values of the conductor layer and the sheath layer to gradually decrease. At the same time, it shortens the time taken for the conductor layer to reach the steady-state value and delays the time for the temperature of the conductor layer to rise to 90°C.

[0115] In this exemplary embodiment, a cable temperature rise simulation device is also provided. Figure 5 It is a simplified structural schematic diagram of the simulation device provided by the embodiment of the present invention. The simulation device includes:

[0116] A model establishment module 100, configured to establish a finite element simulation model according to the structure and laying conditions of the cable; wherein, the finite element simulation model includes a cable simulation model and a pipe rack simulation model;

[0117] A thermal simulation parameter determination module 200, configured to determine the boundary conditions and material parameters of the finite element simulation model; wherein, the boundary conditions include the boundary conditions between the cable and the pipe rack and the boundary conditions between the pipe rack and the external soil, and the material parameters include the thermal conductivity and specific heat capacity;

[0118] A thermal simulation operating condition setting module 300, configured to set the load current of the cable simulation model and the variation function relationship between the thermal conductivity of the external soil and the soil humidity;

[0119] A thermal simulation solution module 400, configured to perform finite element thermal simulation on the finite element simulation model based on the heat conduction equation to obtain the steady-state value reached by the cable temperature under different soil humidity conditions and the time taken to reach the steady-state value.

[0120] In one embodiment, the simulation device in the embodiment of the present invention may further include a loss calculation and determination module, and the loss calculation and determination module is configured to determine the power loss of the cable simulation model; wherein, the power loss of the cable simulation model includes the resistance loss of the conductor layer and the dielectric loss of the insulation layer.

[0121] The cable temperature rise simulation device provided by this embodiment can achieve cable temperature rise simulation calculation, so as to obtain the steady-state value of the cable temperature under different soil humidity conditions and the time taken for the cable temperature to reach the steady-state value. The cable temperature rise simulation device provided by the embodiment of the present invention can execute the cable temperature rise simulation method provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects for executing the method.

[0122] In an exemplary embodiment of the present disclosure, an electronic device is further provided. The electronic device may include a processor and a memory for storing executable instructions of the processor. Among them, the processor is configured to execute the steps of the cable temperature rise simulation method described in any one of the above embodiments by executing the executable instructions.

[0123] Those skilled in the art can understand that various aspects of the present invention can be implemented as a system, a method or a program product. Therefore, various aspects of the present invention can be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software aspects, which can be collectively referred to as "circuit", "module" or "system" here.

[0124] In an exemplary embodiment of the present disclosure, a storage medium is further provided, on which a computer program is stored. When the program is executed by, for example, a processor, the steps of the cable temperature rise method described in any one of the above embodiments can be implemented.

[0125] Regarding the system in the above embodiments, the specific manner in which each unit performs operations has been described in detail in the embodiments related to the method, and will not be elaborated here.

[0126] It should be noted that although several units of the system for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of the two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided and embodied by multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the present disclosure. Those of ordinary skill in the art can understand and implement it without creative work.

[0127] Other embodiments of the present disclosure will be readily apparent to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common general knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the appended claims.

Claims

1. A cable temperature rise simulation method, characterized in that: include: Establishing a finite element simulation model according to the structure and laying conditions of the cable; wherein the finite element simulation model includes a cable simulation model and a pipe simulation model; Determine the boundary conditions and material parameters of the finite element simulation model; wherein the boundary conditions include the boundary conditions between the cable and the row pipe and the boundary conditions between the row pipe and the external soil, and the material parameters include thermal conductivity and specific heat capacity; Setting the load current of the cable simulation model and the changing functional relationship between the thermal conductivity of the external soil and the soil moisture; Finite element thermal simulation is performed on the finite element simulation model based on the heat conduction equation to obtain the steady-state value reached by the cable temperature under different soil moisture conditions and the time taken to reach the steady-state value.

2. The cable temperature rise simulation method according to claim 1, characterized in that: The cable simulation model includes a conductor layer, an insulation layer and a sheath layer, and the cable temperature rise simulation method further includes: Determine the power loss of the cable simulation model; wherein the power loss of the cable simulation model includes the resistance loss of the conductor layer and the dielectric loss of the insulation layer.

3. The cable temperature rise simulation method according to claim 2, characterized in that: The resistance loss of the conductor layer is: W c =I 2 *(1+y s +y p )(1) Where W represents the resistance loss of the conductor layer per unit length, I represents the load current, and y s represents the skin effect factor, y p Indicates the proximity effect factor of the conductor layer; The dielectric loss of the insulating layer is: Among them, W d It represents the resistance loss of the insulation layer per unit length, w is taken as 2πf, f=50Hz, c represents capacitance, U0 represents rated phase voltage, and tanδ represents dielectric loss factor.

4. The cable temperature rise simulation method according to claim 2, characterized in that: The boundary conditions also include a heat transfer boundary condition between the conductor layer and the insulation layer and a heat transfer boundary condition between the insulation layer and the jacket layer.

5. The cable temperature rise simulation method according to claim 2, characterized in that: The heat conduction equation of the conductor layer in the cable simulation model is: Where T represents the temperature at point (x,y), q v represents the heat generation rate per unit volume of the heat source; λ represents the thermal conductivity of the medium; The heat conduction equations of the insulation layer and the sheath layer in the cable simulation model are: Where T is the temperature at point (x,y).

6. The cable temperature rise simulation method according to any one of claims 1 to 5, characterized in that: The relationship between the thermal conductivity of the external soil and the change function of soil moisture is: k=0.10804h+0.5656(5) Where k is the thermal conductivity of the external soil and h is the soil moisture.

7. The cable temperature rise simulation method according to any one of claims 1 to 5, characterized in that: Before performing finite element thermal simulation on the finite element simulation model based on the heat conduction equation, the method further includes: The finite element simulation model is meshed; wherein the mesh density of the cable simulation model is smaller than the mesh density of the pipe simulation model.

8. A cable temperature rise simulation device, characterized in that: include: A model building module is used to build a finite element simulation model according to the structure and laying conditions of the cable; wherein the finite element simulation model includes a cable simulation model and a pipe simulation model; A thermal simulation parameter determination module, used to determine the boundary conditions and material parameters of the finite element simulation model; wherein the boundary conditions include the boundary conditions between the cable and the row pipe and the boundary conditions between the row pipe and the external soil, and the material parameters include thermal conductivity and specific heat capacity; A thermal simulation operation condition setting module, used to set the load current of the cable simulation model and the changing functional relationship between the thermal conductivity of the external soil and the soil moisture; The thermal simulation solution module is used to perform finite element thermal simulation on the finite element simulation model based on the heat conduction equation to obtain the steady-state value reached by the cable temperature under different soil moisture conditions and the time taken to reach the steady-state value.

9. An electronic device, characterized in that: The electronic device comprises: Processor; and A memory, configured to store executable instructions of the processor; Wherein, the processor is configured to execute the steps of the cable temperature rise simulation method according to any one of claims 1 to 7 by executing the executable instructions.

10. A computer storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the cable temperature rise simulation method as described in any one of claims 1 to 7 is implemented.

Images