Cable joint temperature monitoring method and system

Abstract

The invention relates to the technical field of cable joint temperature monitoring, and discloses a cable joint temperature monitoring method and system. A target model is constructed based on equipment data of a cable intermediate joint, regions are divided according to geometric shapes and materials to form a topological structure, and an initial thermal circuit model is constructed in combination with temperature field distribution and a thermal resistance branch; and optimizing the model by using the real-time temperature data, and finally judging the running state of the joint through the thermal circuit model. Complex grid discretization is replaced by an equivalent thermal resistance branch through a thermal circuit model, and the calculation speed is remarkably increased; through topological structure division, the limitation of an analytical method on a regular shape is broken through, and a special-shaped structure can be accurately processed; and the thermal circuit model maps an actual boundary through a thermal resistance parameter, so that an error caused by boundary simplification in an analytical method is avoided. The technical problems that a numerical method and an analytical method adopted by a traditional cable connector need to consider grid division and numerical stability, so that the calculation speed is low, and complex geometrical shapes and boundary conditions cannot be accurately analyzed are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cable joint temperature monitoring, and in particular to a cable joint temperature monitoring method and system. Background Art

[0002] High-voltage cables are essential electrical equipment in power transmission and distribution systems. They are widely used in urban and rural power transmission systems, connecting generators, substations, and large loads. With voltage ratings reaching hundreds of thousands of volts, they are used to transmit high-power electricity, meeting the power needs of factories, commercial buildings, and residential areas. They also play a vital role in connecting long-distance renewable energy generation equipment. However, cable operation is accompanied by thermal effects, and excessive cable temperatures can pose serious risks. High temperatures can cause cable insulation to age, degrading its insulation performance, increasing the risk of electrical failures and even leading to safety incidents such as short circuits and fires. High temperatures also increase cable resistance, reducing power transmission efficiency and resulting in energy waste. Furthermore, high temperatures can affect surrounding cable equipment and the environment, causing overload and damage, and even cascading failures. Therefore, timely monitoring of cable temperature and implementing effective cooling measures are crucial to ensuring the safe and stable operation of power systems.

[0003] However, traditional methods for calculating the temperature of cable joints typically employ analytical and numerical methods, both of which are commonly used in heat conduction and temperature distribution research. Analytical methods rely on analytical solutions to mathematical equations and are generally applicable to situations with simple geometries and boundary conditions. Numerical methods convert the heat conduction equation into a discrete form and approximate the solution using numerical methods. Numerical methods are generally applicable to complex geometries and boundary conditions, and can provide approximate solutions to the temperature distribution and heat conduction process through computer simulation. Common numerical methods include the finite difference method, the finite element method, and the finite volume method. Numerical methods have the advantage of being able to handle complex situations and produce relatively accurate results, but they also require consideration of issues such as meshing and numerical stability, and their computational speed is relatively slow. While analytical methods can calculate temperature distribution and heat conduction processes, they often cannot provide accurate solutions for complex geometries and boundary conditions, which can sometimes limit their use. Summary of the Invention

[0004] The present invention provides a cable joint temperature monitoring method and system, which solves the technical problems that the numerical and analytical methods used in traditional cable joints need to consider grid division and numerical stability, resulting in slow calculation speed and inability to accurately analyze complex geometric shapes and boundary conditions.

[0005] A first aspect of the present invention provides a cable joint temperature monitoring method, comprising:

[0006] Acquire the cable intermediate joint information of the cable to be tested, and build a target cable joint model based on the device data of the cable intermediate joint information based on lightweight technology;

[0007] Dividing the area according to the geometric shape and internal material of the target cable joint model to construct a cable joint topology structure;

[0008] Constructing an initial cable intermediate joint thermal circuit model based on the temperature field distribution of the target cable joint model and the thermal resistance branch of the cable joint topology structure;

[0009] Comparing the effects of various cable body lengths on the cable joint temperature in the initial cable intermediate joint thermal circuit model, determining the optimal cable body length based on the comparison results, and updating the initial cable intermediate joint thermal circuit model to generate an updated cable intermediate joint thermal circuit model;

[0010] Inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model for optimization according to a preset operation scenario to generate a target cable intermediate joint thermal circuit model;

[0011] The target cable intermediate joint thermal circuit model is used to perform early warning judgment on the real-time temperature of the cable intermediate joint of the cable to be tested, and early warning information is generated according to the judgment result.

[0012] Optionally, the acquiring of the cable intermediate joint information of the cable to be tested and constructing a target cable joint model based on the lightweight technology and the device data of the cable intermediate joint information includes:

[0013] Get the middle connector information of the cable to be tested;

[0014] Based on lightweight technology, an initial cable joint model is constructed according to the data of each device of the cable intermediate joint information;

[0015] The insulation structure of the initial cable joint model is adjusted to generate a target cable joint model.

[0016] Optionally, dividing the region according to the geometric shape and internal material of the target cable joint model to construct the cable joint topology structure includes:

[0017] Dividing a plurality of first regions according to the geometric shape of the target cable joint model;

[0018] Dividing a plurality of second regions according to internal materials of the target cable joint model;

[0019] A cable connector topology structure is constructed by using all of the first areas and all of the second areas.

[0020] Optionally, it also includes:

[0021] When current passes through the cable conductor of the target cable joint model, calculating the Joule heat of the cable conductor;

[0022] Under the action of the electric field, calculating the energy loss of the insulating material of the target cable joint model due to polarization hysteresis to obtain the insulating medium loss;

[0023] When an induced electromotive force is generated in the metal sheath of the target cable joint model due to the alternating magnetic field, the circulating current loss is calculated;

[0024] When the alternating magnetic field generates eddy current in the metal sheath, calculating the eddy current loss;

[0025] Determining radial thermal resistance based on resistance to heat conduction from the cable conductor through the insulation material and the metal sheath to the outside;

[0026] Determine the axial thermal resistance based on the resistance to heat conduction along the length of the cable;

[0027] Determining the convective thermal resistance based on the convective heat transfer between the cable surface of the cable to be tested and the air surrounding the cable;

[0028] Determining the radiation thermal resistance based on the radiation heat dissipation of the cable surface to the external environment;

[0029] The Joule heat of the cable conductor, the insulation medium loss, the circulation loss, the eddy current loss, the radial thermal resistance, the axial thermal resistance, the convection thermal resistance and the radiation thermal resistance are input into a thermal circuit model to determine the temperature field distribution of the initial cable intermediate joint thermal circuit model.

[0030] Optionally, constructing an initial cable intermediate joint thermal circuit model based on the temperature field distribution of the target cable joint model and the thermal resistance branch of the cable joint topology structure includes:

[0031] Establishing radial thermal resistance branches in each region according to the temperature field distribution of the target cable joint model and the thermal resistance branches of the cable joint topology structure;

[0032] Based on the axial thermal resistance, the radial thermal resistance branches corresponding to the cable body and the cable intermediate joint of the cable to be tested are connected to generate a three-dimensional thermal path of the cable body and a three-dimensional thermal path of the cable intermediate joint;

[0033] An initial cable intermediate joint thermal circuit model is constructed by using the three-dimensional thermal circuit of the cable body and the three-dimensional thermal circuit of the cable intermediate joint.

[0034] Optionally, comparing the effects of various cable body lengths on the cable joint temperature in the initial cable intermediate joint thermal circuit model, determining the optimal cable body length according to the comparison result, and updating the initial cable intermediate joint thermal circuit model to generate an updated cable intermediate joint thermal circuit model includes:

[0035] Using a thermal circuit algorithm to calculate the cable joint temperatures corresponding to different cable body lengths of the initial cable intermediate joint thermal circuit model, to obtain multiple cable joint temperature calculation results;

[0036] Based on the calculation results of the cable joint temperatures, the effects of the various cable body lengths in the initial cable intermediate joint thermal circuit model on the cable joint temperature are compared, and the optimal cable body length that meets the preset temperature threshold and preset performance requirements is determined according to the comparison results;

[0037] The initial cable intermediate joint thermal circuit model is updated according to the optimal cable body length to generate an updated cable intermediate joint thermal circuit model.

[0038] Optionally, inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model for optimization according to a preset operation scenario to generate a target cable intermediate joint thermal circuit model includes:

[0039] Inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model according to the preset operation scenario, and outputting predicted temperature data;

[0040] Determining whether a difference between the predicted temperature data and the real-time temperature data is within a preset temperature error range;

[0041] If yes, the updated cable intermediate joint thermal circuit model is used as the target cable intermediate joint thermal circuit model;

[0042] If not, dynamically adjust the thermodynamic and model parameters of the updated cable intermediate joint thermal circuit model to generate a new updated cable intermediate joint thermal circuit model, and jump to execute the step of inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model according to the preset operating scenario and outputting the predicted temperature data.

[0043] A second aspect of the present invention provides a cable joint temperature monitoring system, comprising:

[0044] An acquisition module is used to obtain the cable intermediate joint information of the cable to be tested, and based on lightweight technology, build a target cable joint model according to the data of each device of the cable intermediate joint information;

[0045] A first construction module is used to divide the area according to the geometric shape and internal material of the target cable joint model to construct a cable joint topology structure;

[0046] A second construction module is configured to construct an initial cable intermediate joint thermal circuit model based on the temperature field distribution of the target cable joint model and the thermal resistance branch of the cable joint topology structure;

[0047] a comparison module, configured to compare the effects of various cable body lengths in the initial cable intermediate joint thermal circuit model on the cable joint temperature, determine the optimal cable body length based on the comparison result, and update the initial cable intermediate joint thermal circuit model to generate an updated cable intermediate joint thermal circuit model;

[0048] an optimization module, configured to input the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model for optimization according to a preset operation scenario, and generate a target cable intermediate joint thermal circuit model;

[0049] The judgment module is used to perform early warning judgment on the real-time temperature of the cable intermediate joint of the cable to be tested through the target cable intermediate joint thermal circuit model, and generate early warning information according to the judgment result.

[0050] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the cable joint temperature monitoring method as described in any one of the above items.

[0051] A fourth aspect of the present invention provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer executes the cable joint temperature monitoring method as described in any one of the above items.

[0052] It can be seen from the above technical solutions that the present invention has the following advantages:

[0053] This paper constructs a thermal circuit model for cable intermediate joints through lightweight modeling and thermal circuit topology analysis. First, a lightweight target model is constructed based on the equipment data of the cable intermediate joint. The topology is then divided into regions according to geometry and material. An initial thermal circuit model is constructed by combining the temperature field distribution and thermal resistance branches. The optimal parameters are determined by comparing the effect of cable length on temperature. The model is then optimized using real-time temperature data, and the joint's operating status is finally determined using the thermal circuit model. This paper replaces complex mesh discretization with equivalent thermal resistance branches in the thermal circuit model, eliminating the need for iterative solution of large-scale equations and significantly improving computational speed. Through topological partitioning, the complex joint geometry is decomposed into standardized thermal resistance units, overcoming the limitations of analytical methods for regular shapes and enabling accurate processing of irregular-shaped structures. Furthermore, the thermal circuit model maps the actual boundary using thermal resistance parameters, avoiding the errors caused by boundary simplification in analytical methods. This makes it particularly suitable for dynamic heat exchange calculations in complex installation scenarios such as tunnels and underground installations. The model is iteratively updated using real-time temperature data, preserving the engineering calculation accuracy of the thermal circuit method while overcoming the shortcomings of traditional models in characterizing the thermal parameters of nonlinear materials (such as aging insulation) through data-driven analysis, enabling dynamic and accurate prediction of the joint temperature field. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1 A flowchart of a cable joint temperature monitoring method according to the first embodiment of the present invention;

[0056] Figure 2 A schematic structural diagram of an initial cable connector model before simplification provided in the first embodiment of the present invention;

[0057] Figure 3 A flowchart of the steps of a simplified target cable connector model provided in the first embodiment of the present invention;

[0058] Figure 4 A schematic diagram of heat flow distribution of a cable connector provided in Example 1 of the present invention;

[0059] Figure 5 A schematic diagram of the cable connector segment area provided in the first embodiment of the present invention;

[0060] Figure 6 A schematic diagram of the topological structure of a thermal circuit model of a cable intermediate joint provided in the first embodiment of the present invention;

[0061] Figure 7This is a structural block diagram of a cable joint temperature monitoring system provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0062] The embodiments of the present invention provide a cable joint temperature monitoring method and system for solving the technical problems that the numerical and analytical methods used in traditional cable joints need to consider mesh division and numerical stability, resulting in slow calculation speed and inability to accurately analyze complex geometric shapes and boundary conditions.

[0063] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0064] See also Figure 1 , Figure 1 This is a flowchart of the steps of a cable joint temperature monitoring method provided in Example 1 of the present invention.

[0065] The present invention provides a cable joint temperature monitoring method, comprising the following steps:

[0066] Step 101: Obtain the cable intermediate joint information of the cable to be tested, and build a target cable joint model based on the device data of the cable intermediate joint information based on the lightweight technology.

[0067] In the embodiment of the present invention, the cable to be tested refers to a cable whose intermediate joint needs to be temperature monitored.

[0068] Cable joint information refers to the collection of all physical, electrical, structural, and environmental parameters related to the cable joint. This information is key raw data supporting model construction. Examples include the geometric dimensions and material properties of physical structural parameters. Geometric dimensions include the overall joint length, the diameter, thickness, and spatial arrangement of each component (conductor, insulation, shield, sheath, stress cone, etc.), such as the stress cone angle and the insulation layer thickness. These dimensions directly affect the length and cross-sectional area of ​​the heat conduction path. Material properties include the thermophysical properties (such as thermal conductivity, specific heat capacity, and density), electrical properties (resistivity, dielectric constant), and mechanical properties (elastic modulus, etc.) of each component material. For example, the resistivity of copper conductors determines Joule heating losses, while the thermal conductivity of insulation materials affects radial thermal resistance. Electrical operating parameters include rated voltage, rated current, actual operating current, and short-circuit current. Current parameters directly determine the amount of Joule heating generated in the conductor, while voltage parameters affect the dielectric loss of the insulation material.

[0069] Lightweight technology refers to a system of techniques that reduces model complexity and improves computational efficiency by streamlining data, optimizing structures, and improving algorithms while preserving key features. Lightweight modeling software or independently developed parametric modeling tools are typically used to automatically generate models using scripting languages, eliminating the time and errors associated with manual modeling.

[0070] The target cable joint model refers to a target digital model constructed through lightweight technology based on the cable intermediate joint information.

[0071] By extracting data from cable design drawings, product manuals, installation records and other documents, sensors can also be used to collect data on the intermediate cable joints in operation in real time, and the target cable joint model can be constructed using the data of various devices using lightweight modeling software or independently developed parametric modeling tools.

[0072] Furthermore, step 101 includes the following sub-steps:

[0073] S11. Obtain information about the middle connector of the cable to be tested.

[0074] In the embodiment of the present invention, the data of the intermediate joints of the cable in operation can be collected in real time by sensors by extracting the data from the cable design drawings, product manuals, installation records and other documents.

[0075] S12. Based on lightweight technology, an initial cable joint model is constructed according to the data of each device of the cable intermediate joint information.

[0076] In the embodiment of the present invention, see Figure 2 ,Use lightweight modeling software or independently developed parametric modeling tools to use the various equipment data of the cable intermediate joint data to build the initial cable joint model.

[0077] S13. Adjust the insulation structure of the initial cable joint model to generate a target cable joint model.

[0078] In the embodiment of the present invention, taking the YJJJ(T)-220 kV cable intermediate joint as an example, for the cable joint, since a small amount of asymmetric structures such as the grounding column have little effect on the conductor temperature, the cable joint can be equivalent to an axisymmetric structure, and the joint is considered to be isotropic along the radial direction. For the adjustment of the grounding column, copper shell pad, shielding tube, stress cone, PVC tape, crimping tube and copper shell, the maximum increase in the cable conductor temperature and the surface temperature of the joint copper shell will not exceed 1°C, and the temperature of the cable insulation and the joint insulation is almost the same as the temperature before simplification, so such insulation structures can be omitted and simplified. Under the premise of ensuring the accuracy of the model, these insulation structures can be omitted and simplified, thereby simplifying the entire initial cable joint model. This treatment can not only reduce the complexity of the model, but also improve the efficiency of the simulation calculation, which is convenient for further analysis and research. The cross-sectional structure of the simplified cable joint is as follows Figure 3 As shown in Figure 3, the target cable connector model is obtained after simplification.

[0079] Step 102: Divide the area according to the geometric shape and internal material of the target cable joint model, and construct a cable joint topology structure.

[0080] In the embodiment of the present invention, the internal materials refer to materials such as the cable conductor, metal sheath, insulation material, and copper shell.

[0081] The cable joint topology refers to the physical structure, material distribution and heat conduction path of the cable intermediate joint, which is abstracted into a thermal resistance network model with clear connection relationships.

[0082] Specifically, the target cable joint model already contains the precise geometry of the joint (such as cylindrical structure and stress cone shape) and material distribution (such as copper conductor and cross-linked polyethylene insulation). Based on this, the joint needs to be divided into several sub-regions with uniform thermal characteristics (i.e., thermal resistance nodes). After the region division is completed, the thermal resistance branches between each node need to be defined based on the physical mechanism of heat transfer (conduction, convection, and radiation) to form a topological network.

[0083] Furthermore, step 102 includes the following sub-steps:

[0084] S21. Divide a plurality of first regions according to the geometric shape of the target cable joint model.

[0085] In the embodiment of the present invention, the first region refers to a plurality of regions divided according to the precise geometric shapes of the joints included in the target cable joint model.

[0086] Based on the simplified target cable joint model, the cable joint is divided into the first area based on the geometric shape and radial material composition to facilitate subsequent thermal calculations. For the cable body, a longer length is selected for preliminary modeling. Figure 4Heat transfers from hotter objects to cooler ones. When current is applied to a cable line, the heat generated within the cable connector is transferred to the surrounding environment and adjacent components. In the center of the connector, the radially distributed layers have poorer thermal conductivity than the rest of the structure, resulting in the hottest point being in the center. Heat generated by the current flowing through the connector is transferred axially from the center to the ends.

[0087] S22. Divide the target cable joint model into multiple second regions according to the internal materials.

[0088] In the embodiment of the present invention, the second region refers to a plurality of regions divided according to a plurality of internal materials of the joint included in the target cable joint model.

[0089] Considering the structural characteristics of cable joints, it can be seen that the thickness and material composition of cable joints vary at different axial positions. Differences in thermal conductivity and thickness among different materials result in varying radial thermal resistance in each axial region of the joint. Therefore, considering these differences in joints, when designing the thermal circuit model for high-voltage cable intermediate joints, the joints need to be segmented so that the material composition and geometric dimensions of the cable joints within each segment are consistent. Segmentation is performed based on the shape and internal material distribution of the cable joint, and segmentation occurs when the internal material or joint cross-section changes, thus dividing the joint into the first and second regions.

[0090] At the same time, the cable body should also be divided into sections. The section closer to the joint should be shorter, and the section length can be appropriately increased as the distance from the joint increases.

[0091] S23. Use all the first areas and all the second areas to construct a cable connector topology structure.

[0092] In the embodiment of the present invention, see Figure 5 , combining the cable intermediate joint of the target cable joint model and all the first regions and all the second regions divided by the cable body to form a cable joint topology structure.

[0093] Furthermore, the method further comprises the following sub-steps:

[0094] S31. When current passes through the cable conductor of the target cable joint model, calculate the Joule heating of the cable conductor.

[0095] In the present invention, Joule heating refers to the phenomenon in which, when current passes through a resistive conductor, charges migrate in a directed manner under the action of the electric field and collide with the conductor's lattice, converting electrical energy into heat. This phenomenon is also known as "resistance loss" or "ohmic heating." Its physical essence is the thermal effect of electric current, which follows the Joule-Lenz law: the heat generated by the conductor is proportional to the square of the current, the resistance, and the duration of the current.

[0096] When current flows through the cable conductor, the resistance loss is generated. The cable conductor loss can be calculated by the following formula:

[0097] ; (1)

[0098] ; (2)

[0099] ; (3)

[0100] Where, P1 is the resistance loss power of the cable conductor; I is the effective value of the current passing through the cable conductor; R is the current loss of the cable conductor at AC resistance at ℃; is the DC resistance of the cable conductor at 20°C, ; For cable conductors ℃ AC resistance calculation intermediate value (i.e. AC resistance correlation value before correction), ; is the operating temperature of the cable conductor, °C; is the resistance temperature coefficient of the cable conductor (based on 20°C), 1 / °C; is the skin effect coefficient; is the proximity effect coefficient.

[0101] S32. Under the action of the electric field, calculate the energy loss of the insulating material of the target cable joint model due to polarization hysteresis to obtain the insulating medium loss.

[0102] In the embodiment of the present invention, the insulating dielectric loss refers to the energy loss caused by the polarization of the insulating material lagging behind the change of the electric field under the action of the alternating electric field, which is ultimately released in the form of heat energy.

[0103] Considering the dielectric loss of the insulating material under the action of the electric field, the dielectric loss of the insulating material is calculated. The dielectric loss of the insulating material can be calculated by the following formula:

[0104] ; (4)

[0105] Where, C is the single-phase capacitance of the cable (per unit length), μF / m; is the withstand phase voltage of the insulation layer, V; is the power supply angular frequency; is the dielectric loss angle of the insulation layer; is the rated voltage effective value.

[0106] S33. When an induced electromotive force is generated in the metal sheath of the target cable connector model due to the alternating magnetic field, the circulating current loss is calculated.

[0107] In the embodiments of the present invention, the circulating current loss refers to the energy loss caused by the induced electromotive force generated by the metal sheath of the cable (such as copper tape, aluminum sheath) under the action of the alternating magnetic field, forming a closed loop current (circulating current), and the heating caused by the resistance of the sheath.

[0108] The cable metal sheath loss includes eddy current loss and circulating current loss. The magnitude of eddy current loss and circulating current loss is related to the connection method and grounding method of the sheath. The calculation method of metal sheath loss suitable for high-voltage cable laying method can be obtained by referring to the 2023 version of IEC 60287 standard.

[0109] S34. When the alternating magnetic field generates eddy currents in the metal sheath, calculate the eddy current losses.

[0110] In the embodiments of the present invention, eddy current loss refers to a form of energy loss in the electromagnetic induction phenomenon. Specifically, when a conductor (such as a metal sheath) is in an alternating magnetic field, a closed circular current (called eddy current) is induced inside the conductor, and the Joule heat loss generated by the eddy current on the conductor resistance is the eddy current loss.

[0111] The cable metal sheath loss includes eddy current loss and circulating current loss. The magnitude of eddy current loss and circulating current loss is related to the connection method and grounding method of the sheath. The calculation method of metal sheath loss suitable for high-voltage cable laying method can be obtained by referring to the 2023 version of IEC 60287 standard.

[0112] S35. Determine the radial thermal resistance based on the resistance to heat conduction from the cable conductor through the insulation material and metal sheath to the outside.

[0113] In this embodiment of the present invention, radial thermal resistance refers to a physical quantity that describes the resistance to heat conduction in the radial direction (from the center outward) within a cable connector, measured in K / W (Kelvin / Watt). It reflects the ease with which heat can dissipate from the cable conductor through the multi-layer structure, including the insulation material and metal sheath. The greater the thermal resistance, the more difficult heat conduction becomes, and the higher the system temperature rise.

[0114] Specifically, according to the definition of thermal resistance, the thermal resistance of heat conduction through the entire cylindrical wall is:

[0115] ; (5)

[0116] Where, is the temperature difference between the inside and outside of the cylinder wall (such as the temperature difference between the conductor and the insulation layer interface), is the heat flow, the heat power passing radially through the cylinder wall, which is determined by heat sources such as Joule heat and dielectric loss; The inner diameter of the cylinder wall, such as the outer diameter of the cable conductor and the inner diameter of the insulation layer; The outer diameter of the cylinder wall, such as the outer diameter of the insulation layer and the outer diameter of the metal sheath; is the thermal conductivity of the material, reflecting the thermal conductivity of the material; is the axial length of the cylinder wall, corresponding to the length of the cable connector or line segment.

[0117] In the calculation of cable intermediate joints, the radial thermal resistance is calculated based on the layered structure.

[0118] S36. Determine the axial thermal resistance based on the resistance to heat conduction along the length of the cable.

[0119] In the embodiment of the present invention, axial thermal resistance refers to a physical quantity that describes the "resistance" encountered when heat is conducted along the length direction (axial direction) of the cable.

[0120] The radial thermal paths within the cable joint are connected by axial thermal resistance, forming a three-dimensional thermal model. The same applies to the cable itself. Axial heat transfer occurs in good thermal conductors such as the conductor, aluminum sheath, and copper shell, while axial heat transfer in the insulating material is negligible. Therefore, in the cable joint thermal model, axial thermal resistance exists only between the conductor, aluminum sheath, and copper shell.

[0121] The axial thermal resistance can be calculated using the following formula:

[0122] ; (6)

[0123] Where, is the axial length of the cylinder wall, corresponding to the length of the cable connector or line segment; is the thermal conductivity of the material, reflecting the thermal conductivity of the material; A is the cross-sectional area of ​​axial heat conduction, the cross-sectional area perpendicular to the axial direction (such as the cross-sectional area of ​​the conductor).

[0124] S37. Determine the convection thermal resistance based on the convection heat transfer between the cable surface of the cable to be tested and the air surrounding the cable.

[0125] In the embodiment of the present invention, the convection thermal resistance refers to a physical quantity that describes the “resistance” encountered when heat is transferred from the cable surface to the surrounding air through convection heat transfer.

[0126] Considering the convective heat transfer between the cable surface of the cable under test and the surrounding air, the convective heat transfer is calculated. The convective heat transfer can be calculated by the following formula:

[0127] ; (7)

[0128] (8)

[0129] Where, is the convection heat transfer coefficient of the cable surface, k is the thermal conductivity of air; L is the characteristic length of the object, and for the cable L can be expressed as the outer diameter of the cable replace; is the convection heat transfer thermal resistance of the cable; is the Nusselt number.

[0130] S38. Determine the radiation thermal resistance based on the radiation heat dissipation from the cable surface to the external environment.

[0131] In the embodiment of the present invention, the radiation thermal resistance refers to a physical quantity that describes the “resistance” encountered when heat is transferred from the cable surface to the surrounding environment through thermal radiation.

[0132] The formula for heat transfer from a cable through thermal radiation is as follows:

[0133] ; (9)

[0134] ; (10)

[0135] ; (11)

[0136] Combining equations (9), (10) and (11), the calculation formula for radiation thermal resistance can be derived:

[0137] ; (12)

[0138] Where, is the outer diameter of the cable; is the Boltzmann constant, which is 5.67×10 -8 W / (m 2 ·K 4 ); and is the temperature of the cable and tunnel wall; is the emissivity of the cable surface, which is taken as 0.9 in the model; is the radiation form factor; is the parameter used to calculate the shape factor; is the radiation heat transfer coefficient from the cable surface to the tunnel inner wall.

[0139] S39. Input the Joule heat, insulation medium loss, circulation loss, eddy current loss, radial thermal resistance, axial thermal resistance, convection thermal resistance and radiation thermal resistance of the cable conductor into the thermal circuit model to determine the temperature field distribution of the initial cable intermediate joint thermal circuit model.

[0140] In the embodiment of the present invention, the temperature field distribution refers to the collection and distribution state of temperature values ​​at different positions (points) in the three-dimensional space (or simplified to two-dimensional or one-dimensional) of the cable joint.

[0141] By inputting the Joule heat, insulation medium loss, circulation loss, eddy current loss, radial thermal resistance, axial thermal resistance, convection thermal resistance and radiation thermal resistance of the cable conductor into the thermal circuit model, the temperature field distribution of the initial cable intermediate joint thermal circuit model can be obtained.

[0142] Step 103: construct an initial cable intermediate joint thermal circuit model based on the temperature field distribution of the target cable joint model and the thermal resistance branch of the cable joint topology structure.

[0143] In an embodiment of the present invention, the initial cable intermediate joint thermal circuit model refers to a basic mathematical model constructed based on the thermal-electric analogy principle. Its core is to equate the heat transfer process of the cable intermediate joint to a circuit system, and through abstract modeling of parameters such as thermal resistance and heat source, it can realize rapid calculation or real-time monitoring of temperature.

[0144] Through simulation experiments, we obtain temperature field data for the cable joint (e.g., conductor temperature 95°C, insulation temperature 85°C, ambient temperature 30°C, etc.). This temperature data reflects the "results of heat transfer" and serves as the "temperature boundary" and "heat source input" for the thermal circuit model (e.g., Joule heating of the conductor is the heat source, corresponding to the "current source" of the circuit). By disassembling the physical structure of the cable joint, we identify all heat transfer paths (i.e., "thermal resistance branches"). These "thermal resistance branches" correspond to the "resistance elements" of the circuit, some in series (e.g., radial thermal resistance, which is multi-layer series), and some in parallel (e.g., convection and radiation thermal resistance, which are parallel and both dissipate heat from the surface). The temperature field data is used as constraints for "voltage (temperature difference)" and "current (heat flow)." The thermal resistance branches are treated as "resistance elements" and connected according to the joint topology (series and parallel). This ultimately forms a "thermal circuit network." By inputting heat sources (e.g., Joule heating, dielectric loss, etc.), we can calculate the temperature of each node, thus forming the initial thermal circuit model for the cable joint.

[0145] Furthermore, step 103 includes the following sub-steps:

[0146] S41. According to the temperature field distribution of the target cable joint model and the thermal resistance branch of the cable joint topology structure, a radial thermal resistance branch of each area is established.

[0147] In the embodiment of the present invention, the radial thermal resistance branch refers to a physical quantity in the thermal circuit model of the cable intermediate joint that represents the resistance to heat transfer along the radial direction.

[0148] According to the temperature field distribution of the simplified target cable joint model and the thermal resistance branch corresponding to the segmented area division result of the cable joint topology structure, a radial thermal resistance branch in each segmented area is established.

[0149] The radial heat transfer process of the cable intermediate joint and the cable body can be considered isotropic and is represented by a two-dimensional radial branch in the model. The radial heat transfer in different segmented areas can be represented by this radial thermal resistance branch.

[0150] S42. Based on the axial thermal resistance, the radial thermal resistance branches corresponding to the cable body and the cable intermediate joint of the cable to be tested are connected to generate a three-dimensional thermal path of the cable body and a three-dimensional thermal path of the cable intermediate joint.

[0151] In the embodiment of the present invention, the three-dimensional thermal circuit of the cable body refers to a mathematical model that abstracts the heat transfer process of the cable body (the uniform section excluding the joint) into a heat flow network in a three-dimensional space, and simulates the temperature field distribution of the cable in the radial, axial and circumferential directions through the three-dimensional distribution of "thermal resistance-heat source".

[0152] The three-dimensional thermal circuit of the cable intermediate joint refers to a non-uniform three-dimensional heat flow network model built for the cable joint (the component connecting two sections of cable). It focuses on simulating the heat transfer characteristics and temperature field distribution of the complex internal structure of the joint (such as conductor connection, insulation treatment, and seals) in three dimensions.

[0153] The radial branches of the cable intermediate joint and the cable body are connected respectively through the axial thermal resistance to form a three-dimensional thermal path of the cable intermediate joint and a three-dimensional thermal path of the cable body.

[0154] S43. Use the three-dimensional thermal path of the cable body and the three-dimensional thermal path of the cable intermediate joint to construct an initial cable intermediate joint thermal path model.

[0155] In the embodiment of the present invention, the three-dimensional thermal path of the cable body and the three-dimensional thermal path of the cable intermediate joint are connected to form a cable intermediate joint thermal path model. The topological structure of the cable intermediate joint thermal path model is as follows: Figure 6 shown.

[0156] Step 104 : compare the effects of various cable body lengths on the cable joint temperature in the initial cable intermediate joint thermal circuit model, determine the optimal cable body length based on the comparison results, update the initial cable intermediate joint thermal circuit model, and generate an updated cable intermediate joint thermal circuit model.

[0157] In the embodiment of the present invention, updating the cable intermediate joint thermal circuit model refers to a new cable intermediate joint thermal circuit model obtained by optimizing the initial cable intermediate joint thermal circuit model.

[0158] The thermal circuit algorithm is used to repeatedly calculate the impact of different cable body lengths on the cable joint temperature calculation results, so as to adjust the cable length and select the optimal cable body length that meets the temperature and performance requirements. A new thermal circuit model of the cable intermediate joint is constructed to reduce the calculation amount and improve the calculation efficiency.

[0159] Furthermore, step 104 includes the following sub-steps:

[0160] S51. Calculate the cable joint temperatures corresponding to different cable body lengths of the initial cable intermediate joint thermal circuit model using a thermal circuit algorithm to obtain multiple cable joint temperature calculation results.

[0161] In the embodiment of the present invention, the cable joint temperature calculation result refers to the result of calculating the cable joint temperature of the cable body length of the initial cable intermediate joint thermal circuit model using a thermal circuit algorithm.

[0162] The proposed thermal path algorithm repeatedly calculates the impact of different body lengths on the joint temperature calculation results. The final temperature is calculated based on the body selection of different lengths. The shortest possible cable body is selected to reduce the calculation amount.

[0163] S52. Based on the temperature calculation results of each cable joint, compare the effects of each cable body length in the initial cable intermediate joint thermal circuit model on the cable joint temperature, and determine the optimal cable body length that meets the preset temperature threshold and preset performance requirements based on the comparison results.

[0164] In the embodiment of the present invention, the optimal cable body length refers to the shortest possible cable body length that meets temperature and performance requirements.

[0165] The preset temperature threshold is that the temperature at each point of the cable does not exceed 90°C.

[0166] The default performance requirement is to meet the computing speed.

[0167] Compare the effects of various cable body lengths on the joint temperature calculation results. Adjust the cable length gradually with a fixed step size according to the comparison results. Find the optimal solution with the shortest cable body length (increasing the cable body length again will result in a joint temperature change of less than 1%) while meeting the temperature (no point on the cable should exceed 90°C) and performance requirements (meeting the calculation speed).

[0168] Through repeated iterations and optimization, the cable length was gradually shortened to ensure that the cable length used in the simulation not only met the actual project requirements but also significantly reduced the amount of calculations and improved computational efficiency. Ultimately, the optimal cable length was selected.

[0169] S53: updating the initial cable intermediate joint thermal circuit model according to the optimal cable body length, and generating an updated cable intermediate joint thermal circuit model.

[0170] In the embodiment of the present invention, detailed temperature field modeling and analysis is performed based on the optimal cable body length, that is, the initial cable intermediate joint thermal circuit model is updated / adjusted to obtain an updated cable intermediate joint thermal circuit model, providing an accurate basis and support for subsequent thermal management design.

[0171] Step 105: According to a preset operation scenario, the real-time temperature data of the cable intermediate joint of the cable to be tested is input into an updated cable intermediate joint thermal circuit model for optimization to generate a target cable intermediate joint thermal circuit model.

[0172] In the embodiment of the present invention, the target cable intermediate joint thermal circuit model refers to a new cable intermediate joint thermal circuit model obtained by continuously optimizing and adjusting the updated cable intermediate joint thermal circuit model.

[0173] Based on preset operating scenarios (e.g., rated load, ambient temperature, and other typical operating conditions), real-time temperature data collected by sensors at the cable joint under test (e.g., temperatures of conductors, insulation, and other components) is input into an existing, updated cable joint thermal circuit model. Optimization algorithms (e.g., least squares) are used to iteratively adjust model parameters such as thermal resistance and heat source. The model is then verified for accuracy and corrected, and necessary corrections are made based on the verification results to ensure that the model accurately reflects actual conditions. The cable system is operated under known operating conditions, and these data are compared and analyzed with the model's predicted results. The model's predicted temperatures are aligned with the measured data, ultimately generating a target cable joint thermal circuit model that accurately reflects the current operating status and can be used for temperature prediction and fault warning.

[0174] Furthermore, step 105 includes the following sub-steps:

[0175] S61. According to a preset operation scenario, the real-time temperature data of the cable intermediate joint of the cable to be tested is input into an updated cable intermediate joint thermal circuit model, and predicted temperature data is output.

[0176] In the embodiment of the present invention, updating the temperature data refers to temperature data calculated or predicted by updating the thermal circuit model of the cable intermediate joint.

[0177] The real-time temperature data (such as the temperature values ​​of the conductor, insulation layer, etc.) collected by the sensor at the intermediate joint of the cable to be tested is input into the existing updated thermal circuit model of the intermediate joint of the cable to obtain the predicted temperature data. The optimization algorithm (such as the least squares method) is used to iteratively adjust the parameters such as the thermal resistance and heat source in the model so that the model can predict the temperature.

[0178] Specifically, model constraints are added using real-time monitoring data. Temperature sensors are deployed in the actual operating line to collect the temperature of the cable body or the connector surface, further constraining the calculation model. These sensors can collect real-time temperature data from the cable body or the connector surface. This real-time temperature data is input into the calculation model. The model constraints are mandatory temperature constraints at different temperature measurement points.

[0179] S62: Determine whether the difference between the predicted temperature data and the real-time temperature data is within a preset temperature error range.

[0180] In the embodiment of the present invention, the preset temperature error range is 1%. For example, if the error between the real-time temperature data and the calculated thermal circuit model is less than 1%, the model is considered accurate. If it is greater than 1%, the current and material parameters are calculated by reverse correction starting from the measurement point.

[0181] Calculate the difference between the predicted temperature data and the real-time temperature data, and determine whether the difference is less than 1%.

[0182] S63: If yes, the updated cable intermediate joint thermal circuit model is used as the target cable intermediate joint thermal circuit model.

[0183] In an embodiment of the present invention, if the difference between the predicted temperature data and the real-time temperature data is less than 1%, the cable intermediate joint thermal circuit model is updated as the target cable intermediate joint thermal circuit model.

[0184] S64. If not, dynamically adjust and update the thermodynamic and model parameters of the cable intermediate joint thermal circuit model to generate a new updated cable intermediate joint thermal circuit model, and jump to the step of inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model according to the preset operating scenario, and outputting the predicted temperature data.

[0185] In an embodiment of the present invention, if the difference between the predicted temperature data and the real-time temperature data is greater than 1%, a reverse correction is performed starting from the measurement point, and the current and material parameters are calculated to reflect the changes in the material parameters, that is, the thermodynamics and model parameters of the cable intermediate joint thermal circuit model are dynamically adjusted and updated to obtain a new updated cable intermediate joint thermal circuit model, and the process jumps to step S61.

[0186] Specifically, model constraints are used to calibrate and update model parameters. By continuously acquiring the latest temperature data from sensors, the thermodynamic and electromagnetic characteristic parameters in the model are dynamically adjusted to enable the model to reflect actual operating conditions.

[0187] Step 106: Perform a warning judgment on the real-time temperature of the cable intermediate joint of the cable to be tested using the target cable intermediate joint thermal circuit model, and generate warning information according to the judgment result.

[0188] In an embodiment of the present invention, the early warning information refers to the warning information generated for the overheating risk or abnormal condition that may occur in the cable intermediate joint after analyzing and judging the real-time temperature data through the thermal circuit model of the target cable intermediate joint. The warning information usually includes the actual temperature value, the abnormal location (such as the conductor connection point, the insulation layer), the degree of deviation between the temperature and the safety threshold, the risk level (such as general warning, emergency warning) and the corresponding operation and maintenance suggestions (such as enhanced monitoring, load reduction, maintenance and replacement), which are used to remind the operation and maintenance personnel to take timely measures to prevent faults.

[0189] The real-time temperature data of the target cable intermediate joint (such as the temperature value of each layer and the temperature rise rate) collected are analyzed through the target cable intermediate joint thermal circuit model, and compared with the model prediction value, safety threshold and historical operation data to determine whether there is temperature exceeding the limit, abnormal temperature rise or excessive deviation from the model prediction. Based on the judgment result, early warning information including the location of temperature anomaly, risk level and disposal suggestions is generated to achieve early warning of overheating failure of the cable intermediate joint.

[0190] See also Figure 7 , Figure 7 This is a structural block diagram of a cable joint temperature monitoring system provided in Example 2 of the present invention.

[0191] The present invention provides a cable joint temperature monitoring system, comprising:

[0192] The acquisition module 701 is used to obtain the cable intermediate joint information of the cable to be tested, and build a target cable joint model based on the data of each device of the cable intermediate joint information based on the lightweight technology;

[0193] The first construction module 702 is used to divide the area according to the geometric shape and internal material of the target cable joint model and construct the cable joint topology structure;

[0194] The second construction module 703 is used to construct an initial cable intermediate joint thermal circuit model based on the temperature field distribution of the target cable joint model and the thermal resistance branch of the cable joint topology structure;

[0195] A comparison module 704 is configured to compare the effects of various cable body lengths on the cable joint temperature in the initial cable joint thermal circuit model, determine the optimal cable body length based on the comparison results, and update the initial cable joint thermal circuit model to generate an updated cable joint thermal circuit model.

[0196] The optimization module 705 is used to input the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model according to the preset operation scenario to optimize and generate a target cable intermediate joint thermal circuit model;

[0197] The judgment module 706 is used to perform early warning judgment on the real-time temperature of the cable intermediate joint of the cable to be tested by using the target cable intermediate joint thermal circuit model, and generate early warning information according to the judgment result.

[0198] Furthermore, the acquisition module 701 includes:

[0199] The acquisition submodule is used to obtain the middle connector information of the cable to be tested;

[0200] The first construction submodule is used to construct an initial cable joint model based on the data of each device of the cable intermediate joint information based on lightweight technology;

[0201] The adjustment submodule is used to adjust the insulation structure of the initial cable joint model to generate a target cable joint model.

[0202] Furthermore, the first building block 702 includes:

[0203] A first division submodule is used to divide a plurality of first regions according to the geometric shape of the target cable joint model;

[0204] A second division submodule is used to divide a plurality of second regions according to internal materials of the target cable joint model;

[0205] The second construction submodule is configured to construct a cable connector topology structure by using all the first areas and all the second areas.

[0206] Furthermore, the system also includes:

[0207] A first calculation submodule is configured to calculate the Joule heat of the cable conductor when current passes through the cable conductor of the target cable joint model;

[0208] The second calculation submodule is used to calculate the energy loss caused by polarization hysteresis of the insulation material of the target cable joint model under the action of the electric field to obtain the insulation medium loss;

[0209] The third calculation submodule is used to calculate the circulating current loss when the induced electromotive force is generated in the metal sheath of the target cable joint model due to the alternating magnetic field;

[0210] a fourth calculation submodule, configured to calculate eddy current losses when the alternating magnetic field generates eddy currents in the metal sheath;

[0211] The radial thermal resistance submodule is used to determine the radial thermal resistance based on the resistance of heat to conduction from the cable conductor through the insulation material and metal sheath;

[0212] Axial thermal resistance submodule, used to determine the axial thermal resistance based on the resistance to heat conduction along the length of the cable;

[0213] Convective thermal resistance submodule, used to determine the convection thermal resistance based on the convection heat transfer between the cable surface of the cable under test and the air surrounding the cable;

[0214] The radiation thermal resistance submodule is used to determine the radiation thermal resistance based on the radiation heat dissipation of the cable surface to the external environment;

[0215] The temperature field distribution submodule is used to input the Joule heat, insulation dielectric loss, circulation loss, eddy current loss, radial thermal resistance, axial thermal resistance, convection thermal resistance and radiation thermal resistance of the cable conductor into the thermal circuit model to determine the temperature field distribution of the initial cable intermediate joint thermal circuit model.

[0216] Furthermore, the second building block 703 includes:

[0217] Establish a submodule for establishing radial thermal resistance branches in each area according to the temperature field distribution of the target cable joint model and the thermal resistance branches of the cable joint topology;

[0218] A connection submodule is used to connect the radial thermal resistance branches corresponding to the cable body and the cable intermediate joint of the cable to be tested based on the axial thermal resistance, so as to generate a three-dimensional thermal path of the cable body and a three-dimensional thermal path of the cable intermediate joint;

[0219] The third construction submodule is used to construct an initial cable intermediate joint thermal circuit model using the cable body three-dimensional thermal circuit and the cable intermediate joint three-dimensional thermal circuit.

[0220] Furthermore, the comparison module 704 includes:

[0221] A fifth calculation submodule is configured to calculate the cable joint temperatures corresponding to different cable body lengths of the initial cable intermediate joint thermal circuit model using a thermal circuit algorithm, and obtain multiple cable joint temperature calculation results;

[0222] A comparison submodule is used to compare the effects of various cable body lengths on the cable joint temperature in the initial cable intermediate joint thermal circuit model based on the calculation results of the temperature of each cable joint, and to determine the optimal cable body length that meets the preset temperature threshold and preset performance requirements based on the comparison results;

[0223] The updating submodule is used to update the initial cable intermediate joint thermal circuit model according to the optimal cable body length and generate an updated cable intermediate joint thermal circuit model.

[0224] Furthermore, the optimization module 705 includes:

[0225] An input submodule is used to input the real-time temperature data of the cable intermediate joint of the cable to be tested into the cable intermediate joint thermal circuit model according to the preset operation scenario, and output the predicted temperature data;

[0226] A judgment submodule is used to judge whether the difference between the predicted temperature data and the real-time temperature data is within a preset temperature error range;

[0227] The target model submodule is used for updating the cable intermediate joint thermal circuit model as the target cable intermediate joint thermal circuit model if yes;

[0228] The output submodule is used to dynamically adjust and update the thermodynamic and model parameters of the cable intermediate joint thermal circuit model if not, generate a new updated cable intermediate joint thermal circuit model, and jump to the execution step of inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model according to the preset operating scenario, and outputting the predicted temperature data.

[0229] A third embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed, the cable joint temperature monitoring method according to any embodiment of the present invention is implemented.

[0230] Embodiment 4 of the present invention provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer executes the cable joint temperature monitoring method as described in any embodiment of the present invention.

[0231] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0232] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0233] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0234] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0235] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0236] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cable joint temperature monitoring method, characterized in that: include: Acquire the cable intermediate joint information of the cable to be tested, and build a target cable joint model based on the device data of the cable intermediate joint information based on lightweight technology; Dividing the area according to the geometric shape and internal material of the target cable joint model to construct a cable joint topology structure; Constructing an initial cable intermediate joint thermal circuit model based on the temperature field distribution of the target cable joint model and the thermal resistance branch of the cable joint topology structure; Comparing the effects of various cable body lengths on the cable joint temperature in the initial cable intermediate joint thermal circuit model, determining the optimal cable body length based on the comparison results, and updating the initial cable intermediate joint thermal circuit model to generate an updated cable intermediate joint thermal circuit model; Inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model for optimization according to a preset operation scenario to generate a target cable intermediate joint thermal circuit model; The target cable intermediate joint thermal circuit model is used to perform early warning judgment on the real-time temperature of the cable intermediate joint of the cable to be tested, and early warning information is generated according to the judgment result.

2. The cable joint temperature monitoring method according to claim 1, characterized in that: The method of obtaining the cable intermediate joint information of the cable to be tested and constructing a target cable joint model based on the device data of the cable intermediate joint information based on the lightweight technology includes: Get the middle connector information of the cable to be tested; Based on lightweight technology, an initial cable joint model is constructed according to the data of each device of the cable intermediate joint information; The insulation structure of the initial cable joint model is adjusted to generate a target cable joint model.

3. The cable joint temperature monitoring method according to claim 1, characterized in that: The step of dividing the region according to the geometric shape and internal material of the target cable joint model and constructing the cable joint topology structure includes: Dividing a plurality of first regions according to the geometric shape of the target cable joint model; Dividing a plurality of second regions according to internal materials of the target cable joint model; A cable connector topology structure is constructed by using all of the first areas and all of the second areas.

4. The cable joint temperature monitoring method according to claim 1, characterized in that: Also includes: When current passes through the cable conductor of the target cable joint model, calculating the Joule heat of the cable conductor; Under the action of the electric field, calculating the energy loss of the insulating material of the target cable joint model due to polarization hysteresis to obtain the insulating medium loss; When an induced electromotive force is generated in the metal sheath of the target cable joint model due to the alternating magnetic field, the circulating current loss is calculated; When the alternating magnetic field generates eddy current in the metal sheath, calculating the eddy current loss; Determining radial thermal resistance based on resistance to heat conduction from the cable conductor through the insulation material and the metal sheath to the outside; Determine the axial thermal resistance based on the resistance to heat conduction along the length of the cable; Determining the convective thermal resistance based on the convective heat transfer between the cable surface of the cable to be tested and the air surrounding the cable; Determining the radiation thermal resistance based on the radiation heat dissipation of the cable surface to the external environment; The Joule heat of the cable conductor, the insulation medium loss, the circulation loss, the eddy current loss, the radial thermal resistance, the axial thermal resistance, the convection thermal resistance and the radiation thermal resistance are input into a preset thermal circuit model to determine the temperature field distribution of the target cable joint model.

5. The cable joint temperature monitoring method according to claim 4, characterized in that: The constructing of an initial cable intermediate joint thermal circuit model based on the temperature field distribution of the target cable joint model and the thermal resistance branch of the cable joint topology structure includes: Establishing radial thermal resistance branches in each region according to the temperature field distribution of the target cable joint model and the thermal resistance branches of the cable joint topology structure; Based on the axial thermal resistance, the radial thermal resistance branches corresponding to the cable body and the cable intermediate joint of the cable to be tested are connected to generate a three-dimensional thermal path of the cable body and a three-dimensional thermal path of the cable intermediate joint; An initial cable intermediate joint thermal circuit model is constructed by using the three-dimensional thermal circuit of the cable body and the three-dimensional thermal circuit of the cable intermediate joint.

6. The cable joint temperature monitoring method according to claim 1, characterized in that: The comparing the effects of various cable body lengths on the cable joint temperature in the initial cable intermediate joint thermal circuit model, determining the optimal cable body length according to the comparison result, and updating the initial cable intermediate joint thermal circuit model to generate an updated cable intermediate joint thermal circuit model includes: Using a thermal circuit algorithm to calculate the cable joint temperatures corresponding to different cable body lengths of the initial cable intermediate joint thermal circuit model, to obtain multiple cable joint temperature calculation results; Based on the calculation results of the cable joint temperatures, the effects of the various cable body lengths in the initial cable intermediate joint thermal circuit model on the cable joint temperature are compared, and the optimal cable body length that meets the preset temperature threshold and preset performance requirements is determined according to the comparison results; The initial cable intermediate joint thermal circuit model is updated according to the optimal cable body length to generate an updated cable intermediate joint thermal circuit model.

7. The cable joint temperature monitoring method according to claim 1, characterized in that: The step of inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model for optimization according to the preset operation scenario to generate a target cable intermediate joint thermal circuit model includes: Inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model according to the preset operation scenario, and outputting predicted temperature data; Determining whether a difference between the predicted temperature data and the real-time temperature data is within a preset temperature error range; If yes, the updated cable intermediate joint thermal circuit model is used as the target cable intermediate joint thermal circuit model; If not, dynamically adjust the thermodynamic and model parameters of the updated cable intermediate joint thermal circuit model to generate a new updated cable intermediate joint thermal circuit model, and jump to execute the step of inputting the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model according to the preset operating scenario and outputting the predicted temperature data.

8. A cable joint temperature monitoring system, characterized in that: include: An acquisition module is used to obtain the cable intermediate joint information of the cable to be tested, and based on lightweight technology, build a target cable joint model according to the data of each device of the cable intermediate joint information; A first construction module is used to divide the area according to the geometric shape and internal material of the target cable joint model to construct a cable joint topology structure; A second construction module is configured to construct an initial cable intermediate joint thermal circuit model based on the temperature field distribution of the target cable joint model and the thermal resistance branch of the cable joint topology structure; a comparison module, configured to compare the effects of various cable body lengths in the initial cable intermediate joint thermal circuit model on the cable joint temperature, determine the optimal cable body length based on the comparison result, and update the initial cable intermediate joint thermal circuit model to generate an updated cable intermediate joint thermal circuit model; an optimization module, configured to input the real-time temperature data of the cable intermediate joint of the cable to be tested into the updated cable intermediate joint thermal circuit model for optimization according to a preset operation scenario, and generate a target cable intermediate joint thermal circuit model; The judgment module is used to perform early warning judgment on the real-time temperature of the cable intermediate joint of the cable to be tested through the target cable intermediate joint thermal circuit model, and generate early warning information according to the judgment result.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the cable joint temperature monitoring method according to any one of claims 1 to 7 is implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program stored on a non-transitory computer-readable storage medium, wherein the computer program comprises program instructions, wherein when the program instructions are executed by a computer, the computer is caused to execute the cable joint temperature monitoring method according to any one of claims 1 to 7.

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