High-voltage cable joint temperature field distribution simulation analysis method and system under broadband disturbance

Abstract

The invention relates to the technical field of power systems, in particular to a high-voltage cable joint temperature field distribution simulation analysis method and system under broadband disturbance. Constructing an electric-magnetic-thermal multi-physics field coupling simulation model of the alternating-current high-voltage cable joint to be tested; performing hierarchical grid division on the electric-magnetic-thermal multi-physics field coupling simulation model; simulating the electric-magnetic-thermal multi-physical field coupling simulation model under different broadband disturbance conditions by considering physical field boundary conditions to obtain a broadband temperature field distribution result and harmonic loss distribution data; and according to the broadband temperature field distribution result and the harmonic loss distribution data, quantifying the internal temperature field distribution change characteristics of the high-voltage cable joint under broadband disturbance. According to the method, through accurate simulation calculation of temperature field distribution of the high-voltage cable joint under broadband disturbance, safe and stable operation of the high-voltage cable joint under the broadband disturbance environment is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method and system for simulating and analyzing temperature field distribution of a high-voltage cable joint under broadband disturbance. Background Art

[0002] With the rapid development of the power industry, cross-linked high-voltage cables are used more and more widely in power grids, and the number of cable intermediate joints used has also increased significantly. However, these cable intermediate joints have also become one of the main causes of cable operation failures, posing a serious threat to the stability and security of the power grid. Among them, the phenomenon of cable failures caused by broadband disturbances has become increasingly prominent, posing a serious threat to the stable operation of the power grid.

[0003] The occurrence of broadband disturbance phenomenon is mainly due to the large-scale grid connection of new energy and the increasing proportion of power electronic equipment in the power system. These diversified devices interact with each other in a complex and changeable operating environment, resulting in the emergence of a series of broadband oscillation phenomena such as sub / super synchronous oscillation and high-frequency band resonance. These oscillations not only increase the complexity of the power system, but also have a direct impact on the operating stability of AC high-voltage cables. Specifically, broadband disturbances will generate voltage and current harmonic components in the cable. These harmonic components not only increase the loss of the line, but also cause a significant increase in the heat generation of the cable. Long-term high temperature environment will accelerate the aging process of the cable insulation material, thereby shrinking Shorten the service life of the cable. In addition, broadband disturbances may resonate with the natural frequency of the AC high-voltage cable, further reducing the dynamic stability of the power system and increasing the risk of line failure. Studies have shown that broadband disturbances can cause line voltage fluctuations and affect the stability of the voltage at the end of the AC high-voltage cable transmission line, thereby interfering with the normal operation of the power equipment connected to the end of the line. Although the current research on broadband disturbance phenomena has made certain progress, most research still focuses on new energy generation facilities such as wind farms. There is relatively insufficient research on how broadband disturbances specifically affect AC high-voltage cables, especially in terms of temperature field and electric field distribution.

[0004] Therefore, in-depth exploration of the impact mechanism of broadband disturbance on the internal temperature field distribution characteristics of high-voltage cable joints has become an important issue that needs to be urgently addressed in the current power industry. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method and system for simulating and analyzing the temperature field distribution of high-voltage cable joints under broadband disturbance.

[0006] In a first aspect, the present invention provides a method for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband disturbance, the method comprising the following steps:

[0007] Determine the geometric structure parameters of the AC high-voltage cable joint to be measured, and obtain the environmental factor characteristics and electrothermal properties of the AC high-voltage cable joint to be measured;

[0008] Based on the geometric structure parameters, environmental factor characteristics and electrothermal properties of the AC high-voltage cable joint to be measured, construct an electro-magnetic-thermal multi-physical field coupling simulation model of the AC high-voltage cable joint to be measured;

[0009] According to the physical field characteristics of the electro-magnetic-thermal multi-physical field coupling simulation model, set the physical field boundary conditions of the AC high-voltage cable joint to be measured; the physical field boundary conditions include electromagnetic field boundary conditions and temperature field boundary conditions;

[0010] Based on the geometric characteristics of the AC high-voltage cable joint to be measured, perform hierarchical mesh division on the electro-magnetic-thermal multi-physical field coupling simulation model;

[0011] Considering the physical field boundary conditions, perform simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model under different broadband perturbation conditions to obtain the broadband temperature field distribution results and the harmonic loss distribution data of the AC high-voltage cable to be measured in each material layer;

[0012] Quantify the variation characteristics of the internal temperature field distribution of the high-voltage cable joint under broadband perturbation according to the broadband temperature field distribution results and the harmonic loss distribution data.

[0013] In a further implementation scheme, the electromagnetic field boundary conditions include an axial magnetic field boundary condition where the normal component of the vector magnetic potential is zero, and a radial magnetic field boundary condition where the tangential component of the vector magnetic potential is continuous. The axial magnetic field boundary condition is specifically:

[0014]

[0015] The radial magnetic field boundary condition is specifically:

[0016]

[0017] In the formula, is the vector magnetic potential; n is the boundary normal vector; is the vector magnetic potential on the boundary surface S0; is the vector magnetic potential on the boundary surfaces S1 and S2.

[0018] In a further implementation scheme, the temperature field boundary conditions include a cable surface radiation boundary condition and a cable external air convection heat dissipation boundary condition. The cable surface radiation boundary condition is specifically:

[0019]

[0020] The convective heat dissipation boundary condition of the external air of the cable is specifically as follows:

[0021]

[0022] In the formula, λ is the thermal conductivity; is the gradient of the conductor temperature T in the boundary normal direction; S3 is the boundary surface of the temperature field boundary condition; σ 0 is the Boltzmann constant; ε is the surface emissivity; T f is the cable surface temperature; T amb is the ambient temperature; h is the convective heat transfer coefficient.

[0023] In a further embodiment, the steps of performing hierarchical mesh division on the electro-magnetic-thermal multi-physical field coupling simulation model based on the geometric characteristics of the AC high-voltage cable joint to be measured include:

[0024] Based on the electromagnetic field gradient distribution characteristics in the conductor core region of the electro-magnetic-thermal multi-physical field coupling simulation model, determine the maximum element size and the minimum element size;

[0025] Use the maximum element size and the minimum element size to perform local refined mesh dissection on the conductor core region in the electro-magnetic-thermal multi-physical field coupling simulation model;

[0026] Based on the gentle change characteristics of the physical field in the cable trench air domain outside the AC high-voltage cable joint to be measured, perform coarse mesh division on the cable trench air domain outside the AC high-voltage cable joint to be measured;

[0027] Use the mesh division method controlled by the physical field to perform mesh division on the remaining geometric structures in the electro-magnetic-thermal multi-physical field coupling simulation model except for the conductor core and the cable trench air domain.

[0028] In a further embodiment, the steps of considering the physical field boundary conditions and performing simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model under different broadband perturbation conditions to obtain the broadband temperature field distribution results and the harmonic loss distribution data of the AC high-voltage cable to be measured in each material layer include:

[0029] Perform electro-magnetic-thermal coupling simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model according to the electric field equation and the temperature field equation to obtain the electromagnetic loss of the AC high-voltage cable joint to be measured, and during the simulation calculation process, couple the electromagnetic loss as a heat source to the temperature field; the electromagnetic loss includes conductor joule heat, aluminum sheath circulating current loss, and insulating medium loss;

[0030] Inject a composite current excitation containing fundamental wave current and harmonic currents into the electro-magnetic-thermal multi-physical field coupling simulation model in sequence, and simulate different broadband perturbation conditions through the composite current excitation;

[0031] The electromagnetic-thermal field data generated under the fundamental wave current and each harmonic current will be superimposed in the frequency domain to generate the broadband temperature field distribution result of the AC high-voltage cable under test under broadband perturbation;

[0032] Based on the broadband temperature field distribution result, the volume integral of each material layer of the AC high-voltage cable under test is calculated by the volume integral method;

[0033] According to the volume integral of each material layer of the AC high-voltage cable under test, the harmonic loss distribution data of the AC high-voltage cable under test within each material layer is calculated.

[0034] In a further embodiment, the conductor Joule heat is specifically:

[0035] P 1 =I 2 R 20 (1+(1+α(T-20)))(1+Y s +Y p )

[0036] In the formula, P 1 is the conductor Joule heat; I is the conductor core current; R 20 is the resistance of the conductor core at 20°C; α is the temperature coefficient of copper; T is the conductor temperature; Y s is the skin effect factor; Y p is the proximity effect factor.

[0037] In a further embodiment, the step of injecting a composite current excitation including a fundamental wave current and each harmonic current into the electro-magnetic-thermal multi-physical field coupling simulation model includes: injecting harmonic currents with different frequencies and amplitudes according to a preset harmonic spectrum.

[0038] In a further embodiment, the geometric structure parameters of the AC high-voltage cable joint under test include the radial dimensions and axial extension lengths of the cable core, inner semi-conductive shielding layer, outer semi-conductive shielding layer, XLPE insulation layer, and metal aluminum sheath.

[0039] In a further embodiment, the electro-thermal properties include electrical properties and thermal properties; among them, the electrical properties include conductivity, relative permittivity, and magnetic permeability; the thermal properties include specific heat capacity, thermal conductivity, and thermal diffusivity of the laying environment of the AC high-voltage cable joint under test.

[0040] In a second aspect, the present invention provides a simulation analysis system for the temperature field distribution of a high-voltage cable joint under broadband perturbation, and the system includes:

[0041] A parameter acquisition module, configured to determine the geometric structure parameters of the AC high-voltage cable joint to be measured, and acquire the environmental factor characteristics and electro-thermal properties of the AC high-voltage cable joint to be measured;

[0042] A model construction module, configured to construct an electro-magnetic-thermal multi-physical field coupling simulation model of the AC high-voltage cable joint to be measured based on the geometric structure parameters, environmental factor characteristics and electro-thermal properties of the AC high-voltage cable joint to be measured;

[0043] A boundary setting module, configured to set the physical field boundary conditions of the AC high-voltage cable joint to be measured according to the physical field characteristics of the electro-magnetic-thermal multi-physical field coupling simulation model; the physical field boundary conditions include electromagnetic field boundary conditions and temperature field boundary conditions;

[0044] A mesh generation module, configured to perform hierarchical mesh generation on the electro-magnetic-thermal multi-physical field coupling simulation model based on the geometric characteristics of the AC high-voltage cable joint to be measured;

[0045] A simulation module, configured to perform simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model under different broadband perturbation conditions considering the physical field boundary conditions, to obtain the broadband temperature field distribution results and the harmonic loss distribution data of the AC high-voltage cable to be measured in each material layer;

[0046] A simulation analysis module, configured to quantify the variation characteristics of the internal temperature field distribution of the high-voltage cable joint under broadband perturbation according to the broadband temperature field distribution results and the harmonic loss distribution data.

[0047] The present invention provides a method and system for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband perturbation. The method constructs an electro-magnetic-thermal multi-physical field coupling simulation model of the AC high-voltage cable joint to be measured based on the geometric structure parameters, environmental factor characteristics and electro-thermal properties of the AC high-voltage cable joint to be measured; sets the physical field boundary conditions of the AC high-voltage cable joint to be measured according to the physical field characteristics of the electro-magnetic-thermal multi-physical field coupling simulation model; performs hierarchical mesh generation on the electro-magnetic-thermal multi-physical field coupling simulation model based on the geometric characteristics of the AC high-voltage cable joint to be measured; performs simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model under different broadband perturbation conditions considering the physical field boundary conditions, to obtain the broadband temperature field distribution results and the harmonic loss distribution data of the AC high-voltage cable to be measured in each material layer; and quantifies the variation characteristics of the internal temperature field distribution of the high-voltage cable joint under broadband perturbation according to the broadband temperature field distribution results and the harmonic loss distribution data. Compared with the prior art, this method realizes accurate simulation calculations of the temperature field distribution of the high-voltage cable joint under broadband perturbation by constructing an electro-magnetic-thermal multi-physical field coupling simulation model, provides a theoretical basis and data support for optimizing the cable joint design, improving the insulation performance and reducing the fault risk, and ensures its safety and reliability in a complex electromagnetic environment. Brief Description of the Drawings

[0048] Figure 1 is a schematic flow chart of a simulation analysis method for the temperature field distribution of a high - voltage cable joint under broadband disturbances provided by an embodiment of the present invention;

[0049] Figure 2 is a schematic radial cross - section view of a high - voltage cable joint provided by an embodiment of the present invention;

[0050] Figure 3 is a schematic axial cross - section view of a high - voltage cable joint provided by an embodiment of the present invention;

[0051] Figure 4 is a schematic geometric structure diagram of a finite - element simulation software for a high - voltage cable joint in a cable trench laying environment provided by an embodiment of the present invention;

[0052] Figure 5 is a schematic mesh division view of an AC high - voltage cable conductor core provided by an embodiment of the present invention;

[0053] Figure 6 is a schematic overall mesh division view of a high - voltage cable joint including a cable trench laying environment provided by an embodiment of the present invention;

[0054] Figure 7 is a contour map of the temperature field distribution under the working conditions of a high - voltage cable joint provided by an embodiment of the present invention;

[0055] Figure 8 is an axial temperature gradient diagram under the working conditions of a high - voltage cable joint provided by an embodiment of the present invention;

[0056] Figure 9 is a schematic diagram of a radial temperature change curve from the cable core to the outer surface under the working conditions of a high - voltage cable joint provided by an embodiment of the present invention;

[0057] Figure 10 is a contour map of the axial magnetic flux density distribution under the working conditions of a high - voltage cable joint provided by an embodiment of the present invention;

[0058] Figure 11 is a schematic diagram of an axial temperature change curve at each frequency when a high - voltage cable joint undergoes sub - synchronous oscillation provided by an embodiment of the present invention;

[0059] Figure 12 is a schematic diagram of an axial temperature change curve at each frequency when a high - voltage cable joint undergoes super - synchronous oscillation provided by an embodiment of the present invention;

[0060] Figure 13 is a schematic diagram of an axial temperature change curve at each frequency when a high - voltage cable joint undergoes high - frequency resonance provided by an embodiment of the present invention;

[0061] Figure 14It is the block diagram of the simulation analysis system for the temperature field distribution of high-voltage cable joints under broadband disturbances provided by the embodiments of the present invention. Specific embodiments

[0062] The following specifically illustrates the embodiments of the present invention in conjunction with the accompanying drawings. The given embodiments are only for illustrative purposes and should not be construed as limiting the present invention. The accompanying drawings are only for reference and illustration and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0063] Reference Figure 1 , the embodiments of the present invention provide a simulation analysis method for the temperature field distribution of high-voltage cable joints under broadband disturbances. As Figure 1 shown, the method includes the following steps:

[0064] S1. Determine the geometric structure parameters of the AC high-voltage cable joint to be measured, and obtain the environmental factor characteristics and electro-thermal properties of the AC high-voltage cable joint to be measured.

[0065] Specifically, in this embodiment, according to the specification model of the AC high-voltage cable joint to be measured, the geometric structure parameters of the high-voltage cable joint and the material parameters of the cable joint are determined. The geometric structure parameters of the AC high-voltage cable joint to be measured include the radial dimensions and axial extension lengths of the cable core, inner semi-conductive shielding layer, outer semi-conductive shielding layer, XLPE insulation layer, and metal aluminum sheath. In this embodiment, the AC high-voltage cable joint of YJJJTI1-64 / 1101×1200m 2 is taken as an example. As Figure 2 , Figure 3 shown, the high-voltage cable joint includes a cable core, a semi-conductive shielding layer, a metal connecting pipe, a silicone rubber filling layer, and a stress cone. The cable structure from the inside to the outside is successively the cable core, inner semi-conductive shielding layer, XLPE insulation layer, outer semi-conductive shielding layer, and metal aluminum sheath. Record the radial dimensions (thicknesses) and axial extension lengths of each structural layer. Generally, the axial extension length can be determined according to the actual engineering requirements. Here, it can be assumed to be the standard length. The geometric structure parameters of the 110kV AC high-voltage cable are shown in Table 1:

[0066] Table 1

[0067]

[0068] The material parameters of the 110kV AC high-voltage cable are shown in Table 2:

[0069] Table 2

[0070]

[0071] Meanwhile, for each material such as the cable core, inner / outer semiconductive shielding layer, XLPE insulation layer, and metallic aluminum sheath, in this embodiment, the environmental factor characteristic values and electro-thermal property values of the AC high-voltage cable to be measured can be obtained from the material property database or relevant literature. The electro-thermal properties include electrical properties and thermal properties. Among them, the electrical properties include conductivity, relative permittivity, and magnetic permeability; the thermal properties include specific heat capacity, thermal conductivity, and thermal diffusivity of the laying environment of the AC high-voltage cable joint to be measured. The electrical property parameters of the laying environment of the 110 kV AC high-voltage cable are shown in Table 3:

[0072] Table 3

[0073]

[0074] S2. Based on the geometric structure parameters, environmental factor characteristics, and electro-thermal properties of the AC high-voltage cable joint to be measured, construct an electro-magnetic-thermal multi-physics field coupling simulation model of the AC high-voltage cable joint to be measured.

[0075] S3. According to the physical field characteristics of the electro-magnetic-thermal multi-physics field coupling simulation model, set the physical field boundary conditions of the AC high-voltage cable joint to be measured.

[0076] Specifically, in this embodiment, AutoCAD, COMSOL Multiphysics, or ANSYS, etc. can be selected as the 3D modeling software for electro-magnetic-thermal multi-physics field coupling simulation. According to the geometric structure parameters of the AC high-voltage cable joint to be measured, gradually construct the geometric model of the high-voltage cable joint in the 3D modeling software. Figure 4 As the geometric model of the high-voltage cable joint, and input the material parameters of the AC high-voltage cable joint to be measured, the environmental factor characteristics of the laying conditions of the high-voltage cable joint, and its electro-thermal properties into the geometric model of the high-voltage cable joint to generate an electro-magnetic-thermal multi-physics field coupling simulation model of the high-voltage cable joint. At the same time, according to the actual working conditions of the cable joint, set the physical field boundary conditions. The physical field boundary conditions include electromagnetic field boundary conditions and temperature field boundary conditions. Among them, the electromagnetic field boundary conditions include the axial magnetic field boundary condition where the normal component of the vector magnetic potential is zero, and the radial magnetic field boundary condition where the tangential component of the vector magnetic potential is continuous. The axial magnetic field boundary condition is specifically:

[0077]

[0078] The radial magnetic field boundary condition is specifically:

[0079]

[0080] In the formula, is the vector magnetic potential; n is the boundary normal vector; is the vector magnetic potential on the boundary surface S0; is the vector magnetic potential on the boundary surfaces S1 and S2.

[0081] The temperature field boundary conditions include the radiation boundary condition on the cable surface and the convective heat dissipation boundary condition of the outside air of the cable. The radiation boundary condition on the cable surface is specifically:

[0082]

[0083] The convective heat dissipation boundary condition of the outside air of the cable is specifically:

[0084]

[0085] In the formula, λ is the thermal conductivity; is the gradient of the conductor temperature T in the boundary normal direction; S3 is the boundary surface of the temperature field boundary condition; σ 0 is the Boltzmann constant, σ 0 = 5.67 * 10 -8 ; ε is the surface emissivity. In this embodiment, according to the actual operation situation of the cable, the surface emissivity ε of the cable joint can be taken as 0.6; T f is the cable surface temperature; T amb is the ambient temperature; h is the convective heat transfer coefficient.

[0086] S4. Perform hierarchical mesh division on the electro-magnetic-thermal multi-physical field coupling simulation model based on the geometric characteristics of the AC high-voltage cable joint to be measured.

[0087] In some embodiments, the step of performing hierarchical mesh division on the electro-magnetic-thermal multi-physical field coupling simulation model based on the geometric characteristics of the AC high-voltage cable joint to be measured includes:

[0088] Based on the electromagnetic field gradient distribution characteristics in the conductor core region of the electro-magnetic-thermal multi-physical field coupling simulation model, determine the maximum element size and the minimum element size;

[0089] Use the maximum element size and the minimum element size to perform local refined mesh dissection on the conductor core region in the electro-magnetic-thermal multi-physical field coupling simulation model;

[0090] Based on the characteristic that the physical field of the cable trench air domain outside the AC high-voltage cable joint to be measured changes gently, perform coarse mesh division on the cable trench air domain outside the AC high-voltage cable joint to be measured;

[0091] Adopt a mesh division method controlled by the physical field to perform mesh division on the remaining geometric structures in the electro-magnetic-thermal multi-physical field coupling simulation model except for the conductor core and the cable trench air domain.

[0092] Specifically, the present embodiment can perform preliminary electromagnetic field simulation analysis on the conductor core area in the electric-magnetic-thermal multi-physics field coupling simulation model through electromagnetic field simulation software, calculate the electromagnetic field gradient in the area, and determine the maximum unit size and minimum unit size of the conductor core area mesh according to the distribution of the electromagnetic field gradient. According to the determined maximum unit size and minimum unit size, the conductor core area is meshed. For example, in an area with a large electromagnetic field gradient, the present embodiment can use a smaller unit size to capture subtle changes in the physical field; and in an area with a small electromagnetic field gradient, the present embodiment can use a larger unit size to improve the calculation efficiency. Figure 5 In the illustrated embodiment, the maximum cell size of the conductor core mesh is 0.05, and the minimum cell size is 0.008. The conductor core region presents a high-density mesh. This customized mesh processing can ensure that there is sufficient mesh density in areas with large electromagnetic field gradients to capture subtle changes in the physical field.

[0093] Since the physical field changes in the cable trench air domain are relatively gentle, mainly because they are less affected by the heat dissipated by the cable joint, and the electromagnetic field intensity is low, therefore, this embodiment can use coarse grid division for the cable trench air domain outside the high-voltage cable joint according to the geometric dimensions of the cable trench air domain to improve the calculation efficiency. At the same time, for the remaining geometric structures other than the conductor core and the cable trench air domain, such as the inner semi-conductive shielding layer, the XLPE insulation layer, the outer semi-conductive shielding layer and the metal aluminum sheath, the physical field changes in these areas are between the conductor core area and the cable trench air domain, such as Figure 6 As shown, this embodiment adopts a physical field controlled meshing method to mesh the remaining geometric structures except the conductor core and the cable trench air domain. This physical field controlled meshing method automatically adjusts the mesh density according to the gradient change distribution characteristics of the physical field. For example, in COMSOL Multiphysics software, the "adaptive mesh refinement" function can be used to automatically encrypt or sparse the mesh according to the changes in the electromagnetic field and the temperature field to ensure that there is sufficient mesh density in areas with large changes in the physical field to capture subtle changes in the physical field. Therefore, this embodiment uses customized mesh processing for the conductor core, coarse meshing for the cable trench air domain, and physical field controlled meshing for the remaining geometry. This hierarchical meshing method can ensure that there is sufficient mesh density in key areas to capture subtle changes in the physical field while improving computational efficiency.

[0094] S5. Considering the boundary conditions of the physical field, the electric-magnetic-thermal multi-physical field coupling simulation model is simulated and calculated under different broadband disturbance conditions to obtain broadband temperature field distribution results and harmonic loss distribution data of the AC high-voltage cable to be tested in each material layer.

[0095] In some embodiments, the step of considering the physical field boundary conditions and performing simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model under different broadband perturbation conditions to obtain the broadband temperature field distribution results and the harmonic loss distribution data of the AC high-voltage cable to be measured in each material layer includes:

[0096] Perform electromagnetic-thermal coupling simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model according to the electric field equation and the temperature field equation to obtain the electromagnetic losses of the AC high-voltage cable joint to be measured, and during the simulation calculation process, couple the electromagnetic losses as heat sources to the temperature field; the electromagnetic losses include conductor joule heat, aluminum sheath circulating current loss, and insulating medium loss;

[0097] Inject a composite current excitation containing fundamental current and harmonic currents of each order into the electro-magnetic-thermal multi-physical field coupling simulation model in sequence, and simulate different broadband perturbation conditions through the composite current excitation;

[0098] Perform frequency-domain superposition on the electromagnetic-thermal field data generated under the fundamental current and harmonic currents of each order to generate the broadband temperature field distribution results of the AC high-voltage cable to be measured under broadband perturbation;

[0099] Based on the broadband temperature field distribution results, calculate the volume integral of each material layer of the AC high-voltage cable to be measured through the volume integral method;

[0100] Calculate the harmonic loss distribution data of the AC high-voltage cable to be measured in each material layer according to the volume integral of each material layer of the AC high-voltage cable to be measured.

[0101] Specifically, when simulating the temperature field distribution of the high-voltage cable joint under the simulation calculation conditions, this embodiment uses the electric field equation and the temperature field equation for simulation calculation. Among them, the electric field equation is specifically:

[0102]

[0103] In the formula, is the gradient operator; σ is the conductivity; ω is the angular frequency; ε is the relative dielectric constant; V is the electric potential.

[0104] The temperature field equation is specifically:

[0105]

[0106] In the formula, ρ is the material density; c is the specific heat capacity of the material; T is the working temperature; t is the time; (x, y) is the position coordinate of the AC high-voltage cable joint to be measured; k is the thermal conductivity; q v is the volume heat generation rate.

[0107] Such as Figure 7As shown, through simulation calculation in this embodiment, it can be obtained that under the power frequency current of 800 A, the maximum temperature at the joint of the 110 kV AC high-voltage cable is about 37.4 °C, while the operating temperature of the cable core under the operating state remains at about 34.5 °C. This result is basically consistent with the experimental data provided by the manufacturer, thus verifying the accuracy and reliability of the electro-magnetic-thermal multi-physical field coupling simulation model of the high-voltage cable joint established in this embodiment. As Figure 8 shown, through further analysis of the temperature field distribution in this embodiment, it can be found that the temperature at the middle joint of the cable is the highest, followed by the cable core. This is mainly because the middle joint realizes electrical connection through mechanical means, and there is a large contact thermal resistance between the joint and the conductor, resulting in more heat generation at the joint than the body. At the same time, to ensure the insulation performance, the size of the semi-conductive shielding layer of the joint is much larger than that of the body semi-conductive shielding layer, and the heat dissipation capacity of the joint is poor. The combined effect of these factors makes the temperature of the joint conductor much higher than that of the body conductor at steady state. Therefore, there is an axial heat transfer process between the joint and the nearby body. In addition, from Figure 9 it can be seen that the temperature gradually decreases from the cable core to the outer surface. The closer to the cable core, the higher the temperature. This is because the Joule loss of the cable core is the main heat source of the cable, resulting in the highest steady-state temperature of the cable core.

[0108] In the process of simulation calculation, in this embodiment, the electric field and the magnetic field are coupled through the principle of electromagnetic induction. For example, the change in current in the cable joint will generate a magnetic field around it, and the change in the magnetic field will generate an induced electromotive force in the cable joint. By inputting these coupling relationships into the simulation model, in this embodiment, the magnetic field and the thermal field can be coupled through the Joule heat effect. For example, when the current passes through the cable joint, heat will be generated, and the heat will change the temperature distribution of the cable joint; the electric field and the thermal field can be coupled through the conductive loss. For example, when the current passes through the cable joint, conductive loss will be generated, and the conductive loss will be converted into heat, and the heat will change the temperature distribution of the cable joint. Therefore, in this embodiment, the conductor Joule heat, the aluminum sheath circulating current loss, and the insulation dielectric loss of the high-voltage cable joint are calculated, and these electromagnetic losses are used as heat sources to be coupled into the temperature field for electro-magnetic-thermal coupling simulation calculation. Among them, the calculation of the conductor Joule heat takes into account factors such as the core current and the core resistance. The core resistance is affected by temperature, skin effect, and proximity effect; the aluminum sheath circulating current loss is calculated through the loss coefficient of the metal sheath; the insulation dielectric loss is related to the load current, insulation layer capacitance, voltage applied to the insulation medium, and dielectric loss angle in the AC high-voltage cable. The specific conductor Joule heat is:

[0109] P 1 =I 2 R 20 (1+(1+α(T - 20)))(1+Y s +Y p )

[0110] Wherein, P 1 is the Joule heat of the conductor; I is the current of the conductor core; R 20 is the resistance of the conductor core at 20°C; α is the temperature coefficient of copper; T is the conductor temperature; Y s is the skin effect factor; Y p is the proximity effect factor.

[0111] The circulating current loss of the aluminum sheath is specifically:

[0112] P 2 = λ 1 I 2 R

[0113] Wherein, P 2 is the circulating current loss of the aluminum sheath; λ 1 is the circulating current loss coefficient generated by the alternating current voltage in the metal sheath; I is the current of the conductor core; R is the alternating current resistance of the conductor.

[0114] The dielectric loss is specifically:

[0115] P 3 = 2πfcU 2 tanδ

[0116] Wherein, P 3 is the dielectric loss; f is the load current in the AC high-voltage cable; c is the capacitance of the insulation layer; U is the voltage applied to the dielectric; δ is the dielectric loss angle.

[0117] As one of the main heat sources of the cable, the analysis of the internal magnetic field of the AC high-voltage cable joint on the temperature distribution of the cable body is crucial. The axial magnetic flux density distribution nephogram is as Figure 10 shown. From Figure 6 it can be seen that the internal magnetic field distribution of the cable joint is basically centrosymmetric, and the magnetic flux density modulus at the joint is the largest, with a value of 1.4×10-3T, which is basically consistent with the temperature field distribution, indicating that the losses of the shielding layer and the insulation layer are the largest here.

[0118] In order to study the influence of broadband disturbances on high-voltage cable joints, in this embodiment, simulation calculations are carried out under broadband disturbances. In the simulation model, harmonic currents with different frequencies and amplitudes are injected according to the preset harmonic spectrum. These harmonics can have different frequencies and amplitudes to simulate the broadband disturbance conditions in actual operation. Through the combined solution function of the finite element simulation software, the simulation results of the fundamental current and harmonic currents are combined to obtain the overall electromagnetic field distribution under broadband disturbances. The electromagnetic-thermal field data generated under the fundamental current and each harmonic current are superimposed in the frequency domain to obtain the temperature field distribution results under broadband disturbances. Specifically, in this embodiment, harmonic currents with various frequencies and amplitudes are applied to the high-voltage cable joint, and the simulation results of the fundamental current and harmonic currents are combined by using the combined solution function of the finite element simulation software. Under various parameter conditions, the temperature field distribution of the broadband disturbance simulation model of the high-voltage cable joint is calculated by simulation, the harmonic losses under various frequency and amplitude parameters are calculated by simulation, the simulation results are analyzed, and the influence of broadband disturbances on the temperature field distribution and harmonic losses of the high-voltage cable joint is evaluated. In the specific implementation process, in this embodiment, parameterized scans of the current frequencies and amplitudes are set in the finite element simulation software, and the obtained parameterized scan results are combined by using the combined solution function of the software. Then, in this embodiment, the temperature field distribution result dataset is set as the combined solution, and by using the finite element simulation software, the geometric division of each material layer in the simulation model is carried out by using the volume integral method, the volume integrals of each layer structure are calculated, and further the harmonic loss distribution data of each layer structure of the AC high-voltage cable are obtained.

[0119] Through simulation calculation and analysis, in this embodiment, various frequency and amplitude parameters can be combined in the finite element simulation analysis software to analyze the influence of broadband disturbances on the temperature field distribution of the middle joint of the AC high-voltage cable and the calculation of harmonic losses. By calculating the harmonic losses of each layer structure of the AC high-voltage cable joint and comparing and analyzing the electromagnetic losses of each component under normal operating conditions and broadband disturbances, the weak insulation points of the AC high-voltage cable joint can be analyzed. Figure 11 It can be seen that in the ultra-low frequency range (1 Hz to 10 Hz), the influence of subsynchronous oscillation on the temperature distribution of the AC high-voltage cable is very small, and its temperature distribution is relatively close to Figure 4 the temperature distribution under the cable operating conditions shown. However, as the subsynchronous oscillation frequency further increases, the temperature change of the cross-linked cable becomes very drastic. This phenomenon is due to the fact that the conductor dielectric loss is small at ultra-low frequencies, and as the frequency increases, the conductor dielectric loss gradually increases.

[0120] In this embodiment, by comparing Figure 8 and Figure 11It can be found that when subsynchronous oscillation occurs, the uniformity of its temperature field distribution is further reduced, which is likely to trigger the risk of local overheating. In addition, the temperature difference between the cable joint and the cable body increases, accelerating the aging process of the cable insulation material and the conductor, thus increasing the fault risk. From Figure 12 It can be seen that when the same conductor current is passed through the conductor, supersynchronous oscillation is extremely harmful to AC high-voltage cables, and the temperatures at various frequencies have exceeded the long-term insulation withstand temperature. This is because in the case of supersynchronous oscillation, due to the relatively high oscillation frequency, the dielectric loss of its insulation is greater, and the current changes relatively fast, resulting in more heat accumulation inside the cable, thus causing the cable temperature to rise. At the same time, due to the relatively high oscillation frequency, the peak temperature region is relatively wide.

[0121] From Figure 13 It can be seen that when the AC high-voltage cable has high-frequency resonance and the load current is 1200 A, the temperature of the cable joint is about 460 °C, and the temperatures at both ends of the cable body are about 134 °C. Moreover, the temperatures at various positions of the AC high-voltage cable do not change significantly with the frequency. This is because the skin effect inside the AC high-voltage cable gradually tends to be saturated, that is, the distribution of the current on the surface of the conductor no longer changes significantly, so the rate of temperature rise will also slow down. To sum up, through simulation calculation and analysis in this embodiment, the influence of broadband disturbances on high-voltage cable joints can be deeply understood, providing strong technical support for the design, operation, and maintenance of cables.

[0122] S6. Quantify the change characteristics of the internal temperature field distribution of the high-voltage cable joint under broadband disturbances according to the broadband temperature field distribution results and the harmonic loss distribution data.

[0123] In this embodiment, an electro-magnetic-thermal multi-physical field coupling simulation model of the high-voltage cable joint is constructed by means of finite element simulation, effectively avoiding the limitations of high cost and difficult operation in traditional experiments. During the model construction process, this embodiment fully considers factors such as the cable trench laying environment, enabling the model to accurately reflect the electromagnetic field and temperature field distribution of the high-voltage cable joint under broadband disturbance conditions, and being able to truly simulate the actual operation of the high-voltage cable joint. At the same time, this embodiment uses the merged solution function provided by the finite element simulation software to input the broadband disturbance into the multi-physical field coupling simulation model in the form of harmonics. This method not only realizes a comprehensive analysis of the fault characteristics and mechanisms of the high-voltage cable joint under broadband disturbance conditions, but also has rapid calculation and accurate results, thus qualitatively analyzing and quantitatively studying the influence of broadband disturbances on AC high-voltage cable joints, such as temperature rise changes and magnetic field harmonic losses of each layer structure, etc., helping to accurately locate the hottest spot inside the cable joint, improve the cable insulation strength, effectively reduce the occurrence of accidents, and ensure the stable operation of the power system.

[0124] An embodiment of the present invention provides a simulation analysis method for the temperature field distribution of a high-voltage cable joint under broadband disturbances. The method includes determining the geometric structure parameters of the AC high-voltage cable joint to be measured, and obtaining the environmental factor characteristics and electrothermal properties of the AC high-voltage cable joint to be measured; constructing an electro-magnetic-thermal multi-physical field coupling simulation model of the AC high-voltage cable joint to be measured based on the geometric structure parameters, environmental factor characteristics and electrothermal properties of the AC high-voltage cable joint to be measured; setting the physical field boundary conditions of the AC high-voltage cable joint to be measured according to the physical field characteristics of the electro-magnetic-thermal multi-physical field coupling simulation model; performing hierarchical mesh division on the electro-magnetic-thermal multi-physical field coupling simulation model based on the geometric characteristics of the AC high-voltage cable joint to be measured; considering the physical field boundary conditions, performing simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model under different broadband disturbance conditions to obtain the broadband temperature field distribution results and the harmonic loss distribution data of the AC high-voltage cable to be measured in each material layer; quantifying the change characteristics of the internal temperature field distribution of the high-voltage cable joint under broadband disturbances according to the broadband temperature field distribution results and the harmonic loss distribution data. Compared with the prior art, this method realizes the accurate simulation calculation of the temperature field distribution of the high-voltage cable joint under broadband disturbances by constructing an electro-magnetic-thermal multi-physical field coupling simulation model, provides a theoretical basis and data support for optimizing the cable joint design, improving the insulation performance and reducing the fault risk, and ensures its safety and reliability in a complex electromagnetic environment.

[0125] It should be noted that the magnitudes of the serial numbers of the above processes do not mean the order of execution. The order of execution of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0126] In one embodiment, as Figure 14 shown, an embodiment of the present invention provides a simulation analysis system for the temperature field distribution of a high-voltage cable joint under broadband disturbances. The system includes:

[0127] A parameter acquisition module 101, configured to determine the geometric structure parameters of the AC high-voltage cable joint to be measured, and obtain the environmental factor characteristics and electrothermal properties of the AC high-voltage cable joint to be measured;

[0128] A model construction module 102, configured to construct an electro-magnetic-thermal multi-physical field coupling simulation model of the AC high-voltage cable joint to be measured based on the geometric structure parameters, environmental factor characteristics and electrothermal properties of the AC high-voltage cable joint to be measured;

[0129] A boundary setting module 103, configured to set the physical field boundary conditions of the AC high-voltage cable joint to be measured according to the physical field characteristics of the electro-magnetic-thermal multi-physical field coupling simulation model; the physical field boundary conditions include electromagnetic field boundary conditions and temperature field boundary conditions;

[0130] The mesh generation module 104 is configured to perform hierarchical mesh generation on the electro-magnetic-thermal multi-physical field coupling simulation model based on the geometric features of the AC high-voltage cable joint to be measured;

[0131] The simulation module 105 is configured to perform simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model under different broadband perturbation conditions considering the physical field boundary conditions, and obtain the broadband temperature field distribution results and the harmonic loss distribution data of the AC high-voltage cable to be measured in each material layer;

[0132] The simulation analysis module 106 is configured to quantify the change characteristics of the internal temperature field distribution of the high-voltage cable joint under broadband perturbation according to the broadband temperature field distribution results and the harmonic loss distribution data.

[0133] For the specific limitations of a simulation analysis system for the temperature field distribution of a high-voltage cable joint under broadband perturbation, reference can be made to the above limitations on a simulation analysis method for the temperature field distribution of a high-voltage cable joint under broadband perturbation, which will not be elaborated here. Those of ordinary skill in the art can realize that, in combination with the various modules and steps described in the embodiments disclosed in the present application, they can be implemented by hardware, software, or a combination of both. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0134] An embodiment of the present invention provides a simulation analysis system for the temperature field distribution of a high-voltage cable joint under broadband disturbances. The parameter acquisition module of the system determines the geometric structure parameters of the AC high-voltage cable joint to be measured, and acquires the environmental factor characteristics and its electro-thermal properties where the AC high-voltage cable joint to be measured is located. The model construction module constructs an electro-magnetic-thermal multi-physical field coupling simulation model of the AC high-voltage cable joint to be measured based on the geometric structure parameters, environmental factor characteristics and its electro-thermal properties of the AC high-voltage cable joint to be measured; the boundary setting module sets the physical field boundary conditions of the AC high-voltage cable joint to be measured according to the physical field characteristics of the electro-magnetic-thermal multi-physical field coupling simulation model; the mesh division module performs hierarchical mesh division on the electro-magnetic-thermal multi-physical field coupling simulation model based on the geometric characteristics of the AC high-voltage cable joint to be measured; the simulation module performs simulation calculations on the electro-magnetic-thermal multi-physical field coupling simulation model under different broadband disturbance conditions considering the physical field boundary conditions, and obtains the broadband temperature field distribution results and the harmonic loss distribution data of the AC high-voltage cable to be measured in each material layer; the simulation analysis module quantifies the change characteristics of the internal temperature field distribution of the high-voltage cable joint under broadband disturbances according to the broadband temperature field distribution results and the harmonic loss distribution data. Compared with the prior art, the system realizes the accurate simulation calculation of the temperature field distribution of the high-voltage cable joint under broadband disturbances by constructing an electro-magnetic-thermal multi-physical field coupling simulation model, provides a theoretical basis and data support for optimizing the cable joint design, improving the insulation performance and reducing the fault risk, and ensures its safety and reliability in a complex electromagnetic environment.

[0135] The above embodiments only represent several preferred embodiments of the present application, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art of the present technology, several improvements and substitutions can be made without departing from the technical principle of the present application, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the protection scope of the claims.

Claims

1. A simulation analysis method for temperature field distribution of high-voltage cable joints under broadband disturbance, characterized in that: The following steps are involved: Determine the geometrical structural parameters of the AC high voltage cable joint to be tested, and obtain the environmental factor characteristics and electrothermal properties of the AC high voltage cable joint to be tested; Based on the geometric structure parameters, environmental factor characteristics and electrothermal properties of the AC high-voltage cable connector to be tested, an electric-magnetic-thermal multi-physics field coupling simulation model of the AC high-voltage cable connector to be tested is constructed; According to the physical field characteristics of the electric-magnetic-thermal multi-physical field coupling simulation model, the physical field boundary conditions of the AC high-voltage cable connector to be tested are set; the physical field boundary conditions include electromagnetic field boundary conditions and temperature field boundary conditions; Based on the geometric characteristics of the AC high-voltage cable connector to be tested, the electric-magnetic-thermal multi-physics field coupling simulation model is hierarchically meshed; Considering the physical field boundary conditions, the electric-magnetic-thermal multi-physical field coupling simulation model is simulated and calculated under different broadband disturbance conditions to obtain broadband temperature field distribution results and harmonic loss distribution data of the AC high-voltage cable to be tested in each material layer; The temperature field distribution variation characteristics inside the high-voltage cable joint under broadband disturbance are quantified according to the broadband temperature field distribution results and the harmonic loss distribution data.

2. The method for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband disturbance according to claim 1, characterized in that: The electromagnetic field boundary conditions include an axial magnetic field boundary condition in which the normal component of the vector magnetic potential is zero, and a radial magnetic field boundary condition in which the tangential component of the vector magnetic potential is continuous. The axial magnetic field boundary conditions are specifically: The radial magnetic field boundary conditions are specifically: In the formula, is the vector magnetic potential; n is the boundary normal vector; is the vector magnetic potential on the boundary surface S0; is the vector magnetic potential on the boundary surface S1 and the boundary surface S2.

3. The method for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband disturbance as claimed in claim 1, characterized in that: The temperature field boundary conditions include the cable surface radiation boundary conditions and the cable external air convection heat dissipation boundary conditions. The cable surface radiation boundary conditions are specifically: The boundary conditions for the heat dissipation of the cable outside air convection are specifically: Where λ is thermal conductivity; is the gradient of the conductor temperature T in the normal direction of the boundary; S3 is the boundary surface of the temperature field boundary condition; σ0 is the Boltzmann constant; ε is the surface emissivity; T f is the cable surface temperature; T amb is the ambient temperature; h is the convective heat transfer coefficient.

4. The method for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband disturbance according to claim 1, characterized in that: The step of performing hierarchical grid division on the electric-magnetic-thermal multi-physics field coupling simulation model based on the geometric features of the AC high-voltage cable connector to be tested comprises: Determining a maximum unit size and a minimum unit size based on the electromagnetic field gradient distribution characteristics of the conductor core area in the electric-magnetic-thermal multi-physics field coupling simulation model; Using the maximum unit size and the minimum unit size to perform local meshing of the conductor core area in the electric-magnetic-thermal multi-physics field coupling simulation model; Based on the gentle change characteristics of the physical field in the cable trench air domain outside the AC high-voltage cable joint to be tested, the cable trench air domain outside the AC high-voltage cable joint to be tested is coarsely meshed; The meshing method controlled by physical fields is used to mesh the remaining geometric structures except the conductor core and the air domain of the cable trench in the electro-magnetic-thermal multi-physical field coupling simulation model.

5. The method for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband disturbance as claimed in claim 1, characterized in that: The step of considering the physical field boundary conditions, simulating and calculating the electric-magnetic-thermal multi-physical field coupling simulation model under different broadband disturbance conditions, and obtaining broadband temperature field distribution results and harmonic loss distribution data of the AC high-voltage cable to be tested in each material layer comprises: According to the electric field equation and the temperature field equation, the electromagnetic-thermal coupling simulation calculation is performed on the electric-magnetic-thermal multi-physics field coupling simulation model to obtain the electromagnetic loss of the AC high-voltage cable joint to be tested, and in the simulation calculation process, the electromagnetic loss is coupled to the temperature field as a heat source; the electromagnetic loss includes the Joule heat of the conductor, the circulating loss of the aluminum sheath and the loss of the insulating medium; Injecting composite current excitation including fundamental current and harmonic currents into the electric-magnetic-thermal multi-physics field coupling simulation model in sequence, and simulating different broadband disturbance conditions through the composite current excitation; The electromagnetic-thermal field data generated by the fundamental current and each harmonic current are superimposed in the frequency domain to generate the broadband temperature field distribution results of the AC high-voltage cable to be tested under broadband disturbance; Based on the broadband temperature field distribution result, the volume integral of each material layer of the AC high voltage cable to be tested is calculated by a volume integral method; According to the volume fraction of each material layer of the AC high-voltage cable to be tested, the harmonic loss distribution data of the AC high-voltage cable to be tested in each material layer is calculated.

6. A method for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband disturbance as claimed in claim 5, characterized in that: The Joule heat of the conductor is specifically: P1=I 2 R 20 (1+(1+α(T-20)))(1+Y s +Y p ) Where P1 is the Joule heat of the conductor; I is the conductor core current; R 20 is the resistance of the conductor core at 20°C; α is the temperature coefficient of copper; T is the conductor temperature; Y s is the skin effect factor; Y p is the proximity effect factor.

7. A method for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband disturbance as claimed in claim 5, characterized in that: The step of injecting composite current excitation including fundamental current and harmonic currents into the electric-magnetic-thermal multi-physics field coupling simulation model includes: injecting harmonic currents of different frequencies and amplitudes according to a preset harmonic spectrum.

8. The method for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband disturbance according to claim 1, characterized in that: The geometrical structural parameters of the AC high-voltage cable connector to be tested include radial dimensions and axial extension lengths of the cable core, inner semi-conductive shielding layer, outer semi-conductive shielding layer, XLPE insulation layer and metal aluminum sheath.

9. The method for simulating and analyzing the temperature field distribution of a high-voltage cable joint under broadband disturbance according to claim 1, characterized in that: The electrothermal properties include electrical properties and thermal properties; wherein the electrical properties include electrical conductivity, relative dielectric constant and magnetic permeability; the thermal properties include specific heat capacity, thermal conductivity and thermal diffusivity of the installation environment of the AC high-voltage cable connector to be tested.

10. A simulation and analysis system for temperature field distribution of high-voltage cable joints under broadband disturbance, characterized in that: The system comprises: A parameter acquisition module is used to determine the geometric structure parameters of the AC high-voltage cable connector to be tested, and to obtain the environmental factor characteristics and electrothermal properties of the AC high-voltage cable connector to be tested; A model building module is used to build an electric-magnetic-thermal multi-physics field coupling simulation model of the AC high-voltage cable connector to be tested based on the geometric structure parameters, environmental factor characteristics and electrothermal properties of the AC high-voltage cable connector to be tested; A boundary setting module, used to set the physical field boundary conditions of the AC high-voltage cable connector to be tested according to the physical field characteristics of the electric-magnetic-thermal multi-physical field coupling simulation model; the physical field boundary conditions include electromagnetic field boundary conditions and temperature field boundary conditions; A meshing module, used for performing hierarchical meshing of the electric-magnetic-thermal multi-physics field coupling simulation model based on the geometric characteristics of the AC high-voltage cable connector to be tested; A simulation module is used to consider the physical field boundary conditions and simulate the electric-magnetic-thermal multi-physical field coupling simulation model under different broadband disturbance conditions to obtain broadband temperature field distribution results and harmonic loss distribution data of the AC high-voltage cable to be tested in each material layer; The simulation analysis module is used to quantify the change characteristics of the temperature field distribution inside the high-voltage cable joint under broadband disturbance according to the broadband temperature field distribution results and the harmonic loss distribution data.

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