Distribution line conductor critical ice melting current calculation method, device, equipment and medium

Abstract

The invention discloses a distribution line conductor critical ice-melting current calculation method and device, equipment and a medium. The method comprises the following steps: acquiring a first parameter of a distribution line ice-coated conductor in a target application environment and a second parameter of an air environment; establishing a heat balance control model of the iced conductor under the critical ice melting condition; based on the first parameter and the second parameter, determining a heat exchange coefficient between the outer surface of the ice layer of the ice-coated wire and the air environment; and importing the heat exchange coefficient of the outer surface of the ice layer of the iced conductor and the air environment, the first parameter and the second parameter into a heat balance control model, and solving the critical ice melting current of the iced conductor. Accurate solution of the critical ice melting current is realized, hidden dangers of insufficient ice melting or excessive ice melting are effectively eliminated, and the operation safety and reliability of the distribution line are ensured while the ice melting efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ice melting in distribution networks, and in particular to a method, device, equipment and medium for calculating critical ice melting current of distribution line conductors. Background Art

[0002] In related technologies, the selection of critical ice-melting current for ice-covered distribution lines primarily relies on ice-melting tests or theoretical ice-melting models. However, actual engineering applications face complex operating conditions involving the dynamic coupling of multiple parameters, such as ambient temperature, wind speed, and ice thickness. Traditional single tests or models fail to fully cover these conditions, resulting in insufficient accuracy in critical ice-melting current selection and the inability to achieve precise ice-melting control on iced conductors. Summary of the Invention

[0003] The present invention provides a method, device, electronic equipment and medium for calculating the critical ice-melting current of distribution line conductors, so as to solve the technical problem that traditional single test or model method is difficult to fully cover, resulting in insufficient accuracy in selecting the critical ice-melting current and inability to achieve precise ice-melting control of ice-covered conductors.

[0004] In a first aspect, a method for calculating the critical ice melting current of a distribution line conductor is provided, comprising:

[0005] Obtaining a first parameter of an ice-covered conductor of a distribution line under a target application environment and a second parameter of an air environment;

[0006] Establish a thermal balance control model for ice-covered conductors under critical ice melting conditions;

[0007] Determining a heat transfer coefficient between an outer surface of an ice layer of the ice-covered conductor and an air environment based on the first parameter and the second parameter;

[0008] The heat transfer coefficient, the first parameter and the second parameter between the outer surface of the ice layer of the ice-covered conductor and the air environment are introduced into the thermal balance control model to solve the critical ice melting current of the ice-covered conductor.

[0009] In a second aspect, a device for calculating critical ice melting current of a distribution line conductor is provided, comprising:

[0010] An acquisition module, configured to acquire a first parameter of an ice-covered conductor of a power distribution line in a target application environment and a second parameter of an air environment;

[0011] A construction module for establishing a thermal balance control model for ice-covered conductors under critical ice melting conditions;

[0012] a determination module, configured to determine a heat transfer coefficient between an outer surface of an ice layer of an ice-covered conductor and an air environment based on a first parameter and a second parameter;

[0013] The calculation module is used to import the heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment, the first parameter and the second parameter into the heat balance control model to solve the critical ice melting current of the ice-covered conductor.

[0014] In a third aspect, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above-mentioned method for calculating the critical ice melting current of the distribution line conductor are implemented.

[0015] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned method for calculating the critical ice-melting current of the distribution line conductor are implemented.

[0016] The solution implemented by the aforementioned method, device, electronic device, and storage medium for calculating the critical ice-melting current of distribution line conductors accurately calculates the comprehensive heat transfer coefficient between the outer surface of the ice layer and the air medium by collecting the structural characteristic parameters and environmental operating conditions of ice-covered conductors in real time. A dynamic heat balance control model based on the principles of thermodynamic equilibrium is established. This model deeply integrates the dynamic characteristics of the conductors, real-time environmental data, and the heat transfer coefficient field to accurately determine the critical ice-melting current, effectively eliminating the risks of under-melting or over-melting, improving ice-melting efficiency while ensuring the safe and reliable operation of distribution lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. 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 labor.

[0018] Figure 1 1 is a flow chart of a method for calculating critical ice melting current of a distribution line conductor in one embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the cross-sectional structure of a current-carrying conductor in a specific embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the cross-sectional structure of an elliptical ice-covered conductor in a specific embodiment of the present invention;

[0021] Figure 4 Schematic diagram of the relationship between the thickness of the ice layer and the temperature of the outer surface of the ice layer in a specific embodiment of the present invention;

[0022] Figure 5 Schematic diagram showing the effect of ice thickness on critical ice melting current in a specific embodiment of the present invention;

[0023] Figure 6 1 is a schematic structural diagram of a device for calculating critical ice-melting current of a distribution line conductor in one embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, 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. It should be understood that the drawings in the present invention are only for the purpose of illustration and description and are not used to limit the scope of protection of the present invention.

[0025] In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in the present invention illustrate operations implemented according to some embodiments of the present invention. It should be understood that the operations in the flowcharts may be implemented out of sequence, and steps that do not have a logical contextual relationship may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the present disclosure, may add one or more other operations to the flowcharts, or may remove one or more operations from the flowcharts.

[0026] In addition, the embodiments described in the present invention are only some of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0027] It should be noted that the term "comprising" will be used in the embodiments of the present invention to indicate the presence of the features subsequently claimed, but does not preclude the addition of other features. It should also be noted that similar reference numerals and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures.

[0028] The following is a detailed description of this case with reference to the relevant drawings in the specification.

[0029] In the embodiments of this specification, distribution lines are prone to icing under low-temperature, rainy, and snowy weather conditions, which is particularly pronounced in winter. Icing can have a serious impact on transmission equipment, causing safety hazards such as mechanical overload and electrical failure. Among the technical solutions for anti-icing and de-icing of distribution lines, the Short-Circuit Current Ice-Melting (SCCIM) method has become the preferred solution in engineering practice due to its technical reliability and economic advantages. However, when applying this technology, how to accurately determine the critical ice-melting current based on specific meteorological conditions and line parameters remains a key technical problem that needs to be solved urgently.

[0030] Traditional methods, lacking empirical data, rely primarily on ice-melting tests and theoretical models to determine ice-melting currents. However, in actual engineering applications, the dynamic coupling of multiple parameters, such as ambient temperature, wind speed, ice thickness, and morphology, leads to problems such as low efficiency and excessive energy consumption. Furthermore, theoretical models fail to fully account for key factors such as the interfacial characteristics of distribution network conductors, microclimate variations, and the evolution of ice eccentricity, making them difficult to directly apply to distribution line scenarios.

[0031] To address these issues, this application proposes a method for calculating the critical current of distribution network line conductors based on environmental conditions. By studying the geometric morphology of ice-covered conductors, a quantitative description system for their shape parameters is established. Based on the principle of thermodynamic equilibrium, the boundary conditions for short-circuit ice melting are thoroughly analyzed, and a precise calculation model for the critical ice-melting current is established. Furthermore, the impact of key parameters such as wind speed, ambient temperature, ice thickness, and cross-sectional shape on the ice-melting effect is quantitatively evaluated. This method provides a reliable theoretical basis and data support for evaluating the icing status of transmission equipment, predicting development trends, and making operational and maintenance decisions.

[0032] See also Figure 1 This embodiment of the present invention provides a method for calculating the critical ice melting current of a distribution line conductor, the method specifically comprising the following steps:

[0033] S10: Obtain a first parameter of an ice-covered conductor of a distribution line in a target application environment and a second parameter of an air environment.

[0034] It is understandable that the execution subject of the present invention may be a distribution line conductor critical ice melting current calculation device, or a terminal or a server, which is not limited here. The embodiment of the present invention is described by taking a server as the execution subject as an example.

[0035] In this step, the target application environment is an operating environment that meets the basic requirements of short-circuit de-icing technology. For example, the target application environment is a sub-zero icing environment of -5°C to 0°C. When the actual operating conditions of the distribution line meet the application conditions of short-circuit de-icing technology, the characteristic parameters of the iced conductors (first parameters) and the characteristic parameters of the air environment (second parameters) are simultaneously collected.

[0036] By using the above method, the characteristic parameters of the ice-covered conductors and the characteristics of the air environment are collected simultaneously. The required ice-melting current can be accurately calculated according to the actual situation, and a more scientific and reasonable ice-melting plan can be formulated to improve the ice-melting efficiency and avoid incomplete or excessive ice-melting due to improper parameter settings.

[0037] S20: Establish a thermal balance control model for ice-covered conductors under critical ice melting conditions.

[0038] Thermodynamic analysis surface. Under sub-zero ambient conditions, the energized conductor system presents a typical three-layer temperature distribution structure, such as Figure 2 The figure shows the cross-sectional structure of the energized conductor, where the conductor temperature T c = ice surface temperature T in > Ice surface temperature T i >Ambient temperature T a This temperature field distribution forms two key heat transfer gradient fields: the internal conduction gradient ΔT1 = T in -T i , and the ice-air interface heat transfer gradient ΔT2 = T i -T a . These two gradient fields together constitute the thermodynamic driving force system of the ice melting process, in which the internal temperature gradient ΔT1 dominates the ice layer phase change dynamics process, while the external gradient ΔT2 determines the heat exchange intensity between the system and the environment. By establishing a thermal balance control model, the thermodynamic characteristics of ice-covered conductors under critical ice melting conditions can be accurately analyzed, the degree of ice coverage of the conductors can be evaluated in real time, and theoretical support can be provided for the calculation of critical ice melting current. This model effectively solves the problem of electric energy waste in the traditional fixed power mode. By comprehensively considering key parameters such as the actual ice thickness of the conductor, ambient temperature and wind speed, the optimal critical ice melting current is dynamically calculated to achieve precise regulation of the ice melting power, thereby significantly improving ice melting efficiency and reducing energy consumption.

[0039] In one embodiment of the present application, a specific heat transfer coefficient calculation scheme is provided. In S20, a heat balance control model of an ice-covered conductor under critical ice melting conditions is established, specifically including the following steps S21-S24:

[0040] S21: Establish a Joule heat calculation model.

[0041] In this step, the heat energy of the wire melting process mainly comes from the Joule heating effect generated when the current passes through, that is:

[0042] q j =I 2 R T ;

[0043] Among them, q j is the Joule heat flow, in W; I is the wire current; R T It is the resistivity of the conductor at ambient temperature, in Ω / m.

[0044] This heat is transferred from the conductor surface through the ice layer to the ice-air interface (the outer surface of the ice layer) by heat conduction. Based on this heat transfer mechanism, a coupled calculation model of Joule heating and ice layer conduction can be established.

[0045] Specifically, the Joule heat calculation model is:

[0046]

[0047] Where I is the conductor current; R T is the conductor resistivity at ambient temperature; T in is the surface temperature of the ice layer; T i (θ) is the outer surface temperature of the ice layer corresponding to the contact angle θ between the ice layer and the wire; R q (θ) is the thermal resistance of the ice layer corresponding to the micro-angle element d(θ); d(θ) is the micro-angle element.

[0048] It should be noted that R T is the conductor resistivity at the current ambient temperature (T°C). When establishing a thermal balance model for an elliptical ice-covered conductor, the contact angle θ between the ice layer and the conductor is an essential parameter. This thermal balance model must account for multiple factors, including heat conduction within the conductor, convective heat transfer with the surrounding air, and radiative heat transfer with the external environment. By incorporating the contact angle θ between the ice layer and the conductor cylinder, these factors can be precisely quantified and analyzed at different locations, leading to a more accurate thermal balance model and providing strong support for predicting conductor temperature changes and ice melting processes.

[0049] S22: Establish a calculation model for the heat loss value on the outer surface of the ice layer.

[0050] In this step, a convection-radiation coupled heat loss calculation model is established based on the heat loss characteristics of the outer surface of the ice layer to quantitatively characterize the comprehensive heat dissipation process at the ice-air interface.

[0051] Specifically, the calculation model for the heat loss value on the outer surface of the ice layer is:

[0052]

[0053] Among them, q i is the heat loss value of the outer surface of the ice layer; h is the heat exchange coefficient between the outer surface of the ice layer and the air environment; T i (θ) is the outer surface temperature of the ice layer at the contact angle θ between the ice layer and the wire; T a is the ambient temperature; r c is the wire radius; d i (θ) is the ice thickness at the contact angle θ between the ice layer and the wire; dθ is the micro-angle element.

[0054] S23: Assume that the critical ice melting conditions are: the cross-section of the ice-covered conductor is an ideal circle, the temperature of the inner surface of the ice layer is 0, and the Joule heat power and the heat dissipation power of the outer surface of the ice layer reach a dynamic equilibrium.

[0055] In this step, to simplify the calculation process of the critical ice-melting current and optimize the configuration of ice-melting equipment parameters in actual engineering applications, a thermal balance control model was established based on the ideal circular cross-section assumption. This simplified model significantly improves engineering applicability and computational efficiency while maintaining accuracy.

[0056] Through the above method, the necessary and sufficient conditions for critical ice melting at short-circuit current are established, the surface temperature of the ice layer is maintained at 0°C, and the balance between Joule heat and surface heat loss is ensured. The ice melting process can be accurately controlled, so that the conductors and ice layer are in the optimal ice melting state, avoiding unnecessary energy consumption and equipment damage.

[0057] Furthermore, when the temperature of the inner surface of the ice layer reaches the critical point of phase transition (0°C), and the Joule heat output and the heat dissipation power of the outer surface of the ice layer reach dynamic equilibrium, the Joule heat output and the heat loss from the outer surface of the ice layer are exactly opposite, indicating that the ice layer is in a critical melting state. This equilibrium state represents the threshold condition between ice maintenance and melting.

[0058] S24: Combine the Joule heat calculation model and the ice layer outer surface heat loss calculation model to establish the heat balance control equation of the heat balance control model.

[0059] In this step, the Joule heat calculation model accurately characterizes the heat generation characteristics of the conductor when energized, while the heat loss calculation model quantifies the convection and radiation heat dissipation of the conductor to the environment. By establishing the thermal balance control equations for the two and comprehensively considering key parameters such as ice thickness, ambient temperature, and wind speed, the optimal current value required for the ice-covered conductor to reach the critical ice-melting state can be dynamically solved. Based on the real-time monitoring and feedback adjustment mechanism of this model, precise closed-loop control of the ice-melting process can be achieved, effectively avoiding under-melting or over-melting, and significantly improving ice-melting efficiency and safety.

[0060] Specifically, the heat balance governing equation is:

[0061]

[0062] S30: Determine a heat transfer coefficient between an outer surface of the ice layer of the ice-covered conductor and an air environment based on the first parameter and the second parameter.

[0063] In this step, the ice melting process is essentially a coupled process of energy transfer and phase change conversion. The Joule heat generated by the current flowing through the conductor must meet two thermodynamic requirements at the same time: providing the latent heat of the ice layer phase change and compensating for the heat convection loss of the conductor to the air. The heat transfer coefficient is a key parameter to characterize the heat transfer intensity of the conductor-air interface. Accurately determining the heat transfer coefficient can improve the accuracy of the ice melting current calculation, avoid energy waste or equipment damage due to excessive current, and prevent incomplete ice melting due to too small current. To this end, the present application proposes to calculate the heat exchange efficiency of the ice layer-air interface based on the multi-dimensional characteristic parameters of the ice-covered conductor and the environmental characteristic parameters, which can more realistically reflect the heat exchange process between the ice-covered conductor and the air under actual working conditions, thereby providing a reliable basis for the calculation of the ice melting current.

[0064] In one embodiment of the present application, a specific heat transfer coefficient calculation scheme is provided. In S30, the heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment is determined based on the first parameter and the second parameter. The scheme specifically includes the following steps S31-S33:

[0065] S31: establishing a dimensionless calculation model, importing the first parameter and the second parameter into the dimensionless calculation model, and solving dimensionless numbers, wherein the dimensionless numbers include: Lagashov number, Prandtl number, and Reynolds number.

[0066] In this step, dimensionless numbers are unitless pure numbers composed of multiple physical quantities, including the Lashof number (Gr), which represents the ratio of buoyancy to viscous forces; the Prandtl number (Pr), which reflects the ratio of momentum diffusion to heat diffusion; and the Reynolds number (Re), which describes the ratio of inertial force to viscous force. A dimensionless calculation model is constructed based on similarity theory, which can standardize and reconstruct the structural characteristic parameters (first parameter) and environmental operating condition parameters (second parameter) of ice-covered conductors. Through dimensional homogenization analysis, the multidimensional physical quantities are systematically converted into dimensionless numbers that represent the thermal-fluid-solid coupling characteristics.

[0067] Specifically, the dimensionless calculation model is:

[0068]

[0069] Where Gr is the Grashof number; g is the gravitational constant; T i is the outer surface temperature of the ice layer; T a is the ambient temperature; r eqThe equivalent ice-covered conductor radius corresponding to the ice-covered cross section of the elliptical ice-covered conductor is an equivalent circular cross section; d i is the thickness of the ice layer; Pr is the Prandtl number; μ is the air viscosity coefficient; Ca is the specific heat capacity of air; λ a is the thermal conductivity of air; Re is the Reynolds number; ν a is the wind speed; ρ a is the air density.

[0070] S32: Determine, based on the dimensionless number, a first Nusselt number of the ice-covered conductor under natural convection conditions and a second Nusselt number of the ice-covered conductor under forced convection conditions.

[0071] In this step, the Nusselt number characterizes the ratio of the convective heat transfer intensity to the pure thermal conductivity. Determining the Nusselt number (Nu) based on the dimensionless number can realize the quantitative evaluation of the heat dissipation characteristics of ice-covered conductors under the combined conditions of natural convection and forced convection.

[0072] In one embodiment of the present application, a specific Nusselt number determination scheme is provided. In S32, the heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment is determined based on the first parameter and the second parameter. The scheme specifically includes the following steps S321-S323:

[0073] S321: Establish a first Nusselt calculation model for ice-covered conductors under natural convection conditions, import the Grashof number and Prandtl number into the first Nusselt calculation model, and solve the first Nusselt number of ice-covered conductors under natural convection conditions.

[0074] In this step, a first-type Nusselt number calculation model for ice-covered conductors under natural convection conditions is constructed. By introducing the Grashof number (Gr) and the Prandtl number (Pr) as input parameters, the characteristic Nusselt number of ice-covered conductors under pure natural convection conditions is obtained.

[0075] The first Nusselt calculation model is:

[0076] Nu n =B×(Gr×Pr) b ;

[0077] Among them, Nu n is the first Nusselt number; B is a constant; Gr is the Grashof number; Pr is the Prandtl number; b is a constant.

[0078] S322: Determine a first convection coefficient and a second convection coefficient based on the Reynolds number.

[0079] In this step, the first and second convection coefficients, dominated by forced convection, are determined based on the Reynolds number flow regime criterion. These two convection coefficients can be used as correction factors to adjust the heat transfer coefficients subsequently calculated based on the dimensionless number and Nusselt number, thereby improving the accuracy of the calculated results.

[0080] Optionally, the mapping relationship between the Reynolds number and the first convection coefficient and the second convection coefficient is shown in Table 1.

[0081] Table 1

[0082]

[0083]

[0084] S323: Establish a second Nusselt calculation model for ice-covered conductors under forced convection conditions, import the Reynolds number, Prandtl number, first convection coefficient and second convection coefficient into the second Nusselt calculation model, and solve the second Nusselt number of the ice-covered conductors under forced convection conditions.

[0085] In this step, a Nusselt number calculation model for ice-covered conductors under forced convection conditions is constructed. By coupling the Reynolds number (Re), Prandtl number (Pr) and bimodal convection coefficient, the characteristic Nusselt number of ice-covered conductors under forced convection-dominated conditions is accurately solved.

[0086] The second Nusselt calculation model is:

[0087]

[0088] Among them, Nu f is the second Nusselt number; C is the first convection coefficient; Re is the Reynolds number; n is the second convection coefficient; Pr is the Prandtl number.

[0089] S33: Determine a heat transfer coefficient between an outer surface of the ice layer of the ice-covered conductor and an air environment based on the dimensionless number, the first Nusselt number, the second Nusselt number, the first parameter, and the second parameter.

[0090] In this step, a heat transfer coefficient calculation model between the outer surface of the ice layer on the conductor and the surrounding air environment can be established using specific dimensionless numbers, the Nusselt number, the structural characteristic parameters of the ice-covered conductor, and the actual operating parameters. The calculation results of this model can accurately reflect the heat exchange characteristics of the ice-covered conductor and provide a reliable theoretical basis for optimizing the ice melting parameters.

[0091] In one embodiment of the present application, a specific heat transfer coefficient calculation scheme is provided. In S33, the heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment is determined based on the dimensionless number, the first Nusselt number, the second Nusselt number, the first parameter, and the second parameter. The scheme specifically includes the following steps S331-S333:

[0092] S331: A calculation model for the convective heat transfer coefficient of the ice layer on the surface of the ice-covered conductor is established. The equivalent ice-covered conductor radius, air thermal conductivity, ice layer thickness, first Nusselt number and second Nusselt number corresponding to the ice-covered conductor having an equivalent circular cross-section are introduced into the calculation model for the convective heat transfer coefficient of the ice layer on the surface of the ice-covered conductor to solve the convective heat transfer coefficient of the ice layer on the surface.

[0093] In this step, a calculation model for the convective heat transfer coefficient on the outer surface of the ice layer is established, assuming an elliptical ice-covered conductor has an equivalent circular cross-section. This model incorporates key parameters such as the equivalent ice-covered conductor radius, air thermal conductivity, ice layer thickness, and the first and second Nusselt numbers to accurately determine the convective heat transfer coefficient on the outer surface of the ice layer.

[0094] Specifically, the calculation model for the convective heat transfer coefficient of the ice layer on the surface of the ice-covered conductor is:

[0095]

[0096] Among them, h c is the convection heat transfer coefficient on the outer surface of the ice layer; a is the thermal conductivity of air; Nu n is the first Nusselt number; Nu f is the second Nusselt number; r eq d is the equivalent ice-covered conductor radius corresponding to the equivalent circular cross-section of the ice-covered conductor; i is the thickness of the ice layer.

[0097] S332: Establish a calculation model for the radiation heat transfer coefficient of the outer surface of the ice layer, import the emissivity of the outer surface of the ice layer and the ambient temperature into the calculation model for the radiation heat transfer coefficient of the outer surface of the ice layer, and solve the radiation heat transfer coefficient of the outer surface of the ice layer.

[0098] In this step, a calculation model for the radiation heat coefficient of the outer surface of the ice layer is constructed. The surface emissivity of the ice layer and the ambient temperature are comprehensively considered, and the accurate radiation heat transfer coefficient of the outer surface of the ice layer is obtained through numerical solution, providing a reliable theoretical basis for the calculation of the heat load of the ice melting process of the de-ice conductor.

[0099] Specifically, the calculation model of the radiation heat transfer coefficient of the outer surface of the ice layer is:

[0100] h r =4εσ(T a +273.15) 3;

[0101] Among them, h r is the radiation heat transfer coefficient of the outer surface of the ice layer; ε is the emissivity of the outer surface of the ice layer; σ is the radiation constant; T a is the ambient temperature.

[0102] S333: Add the convection heat transfer coefficient of the outer surface of the ice layer and the radiation heat transfer coefficient of the outer surface of the ice layer to obtain the heat transfer coefficient between the outer surface of the ice layer and the air environment.

[0103] In this step, during the actual heat transfer process of the ice-covered conductor, the heat transfer between the outer surface of the ice layer and the surrounding air environment is carried out simultaneously by convection and radiation. Convective heat transfer is the heat exchange caused by the flow of air, while radiation heat transfer is the heat transfer in the form of electromagnetic waves. By linearly superimposing the calculated convection heat transfer coefficient and radiation heat transfer coefficient, the heat transfer coefficient between the outer surface of the ice layer and the air environment is obtained, which can fully characterize the combined effect of the two heat transfer modes, thereby more accurately describing the actual heat transfer characteristics of the outer surface of the ice layer. Therefore, the convection heat transfer coefficient h of the outer surface of the ice layer is taken as c and the radiation heat transfer coefficient h on the outer surface of the ice layer r Adding them together, we can get the heat transfer coefficient h between the outer surface of the ice layer and the air environment.

[0104] Through the above method, the two heat transfer modes of convection and radiation are comprehensively considered, which reduces the uncertainty caused by ignoring a certain heat transfer mode and improves the credibility and accuracy of the calculation results.

[0105] S40: The heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment, the first parameter, and the second parameter are introduced into a heat balance control model to solve the critical ice melting current value of the ice-covered conductor.

[0106] In this step, by constructing a thermal balance control model, the dynamic characteristic parameters of the ice-covered conductor and the real-time environmental parameters are fully integrated. Through multi-physical field coupling calculations, the optimal current value of the ice-covered conductor under critical ice melting conditions can be accurately solved, ensuring that the calculation results are dynamically matched with the actual operating conditions.

[0107] In one embodiment of the present application, a specific critical ice-melting current value calculation scheme is provided. In S40, the heat exchange coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment, the first parameter, and the second parameter are introduced into the heat balance control model to solve the critical ice-melting current value of the ice-covered conductor. The scheme specifically includes the following steps:

[0108] The ice layer thermal resistance expression is established as:

[0109]

[0110] Among them, R qis the thermal resistance of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; λ Q1 is the thermal conductivity of the ice layer;

[0111] Substituting the ice layer thermal resistance expression into the heat balance control equation, the calculation model of the ice layer outer surface temperature is obtained:

[0112]

[0113] Among them, T i is the outer surface temperature of the ice layer; Q1 is the thermal conductivity of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; h is the heat transfer coefficient between the outer surface of the ice layer and the air environment; T a is the ambient temperature;

[0114] Substituting the ice layer outer surface temperature calculation model into the Joule heat calculation model, the critical ice melting current calculation model is obtained;

[0115] The critical ice melting current calculation model is:

[0116]

[0117] Among them, I c is the critical ice melting current; Q1 is the thermal conductivity of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; h is the heat transfer coefficient between the outer surface of the ice layer and the air environment; T a is the ambient temperature; R T is the conductor resistivity at ambient temperature;

[0118] The first parameter, the second parameter, and the heat transfer coefficient between the outer surface of the ice layer and the air environment are introduced into the critical ice melting current calculation model to solve the critical ice melting current of the ice-covered conductor.

[0119] In this embodiment, the ice flatness of the ice-covered conductor is set to 0 and the ice eccentricity is set to 0, that is, the cross section of the ice-covered conductor is an ideal circle. i 、r i 、R q is a constant, the thermal resistance of the cylindrical ice layer R q The expression is:

[0120]

[0121] Among them, R q is the thermal resistance of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; λQ1 is the thermal conductivity of the ice layer.

[0122] Substituting the ice layer thermal resistance calculation model into the heat balance control equation, we can obtain:

[0123]

[0124] Among them, T i is the outer surface temperature of the ice layer; Q1 is the thermal conductivity of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; h is the heat transfer coefficient between the outer surface of the ice layer and the air environment; T a is the ambient temperature.

[0125] Through the above expression, the calculation model of the outer surface temperature of the ice layer is converted into:

[0126]

[0127] Furthermore, under critical ice melting conditions, the Joule heat calculation model can be converted to:

[0128]

[0129] Among them, I c is the critical ice melting current; R T is the conductor resistivity at ambient temperature; T i is the outer surface temperature of the ice layer; Q1 is the thermal conductivity of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius.

[0130] Then, the ice layer outer surface temperature calculation model is substituted into the converted Joule heat calculation model to solve the critical ice melting current under critical ice melting conditions:

[0131]

[0132] Among them, I c is the critical ice melting current; Q1 is the thermal conductivity of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; h is the heat transfer coefficient between the outer surface of the ice layer and the air environment; T a is the ambient temperature; R T is the conductor resistivity at ambient temperature.

[0133] Through the above method, the actual ice thickness of the conductor, ambient temperature, wind speed and other key parameters are comprehensively considered, the optimal critical ice-melting current is dynamically calculated, and the ice-melting power is precisely regulated, thereby significantly improving the ice-melting efficiency and reducing energy consumption.

[0134] In one embodiment of the present application, a specific de-icing solution is provided, that is, after introducing the heat transfer coefficient, the first parameter, and the second parameter into a heat balance control model and solving the critical de-icing current of the ice-covered conductor, the following steps are also included:

[0135] Based on the critical ice melting current, the short-circuit conductor current ice melting technology is used to melt the ice-covered conductors of the distribution lines.

[0136] In this embodiment, based on the critical ice-melting current, the short-circuit current ice-melting technology is used to efficiently melt ice-covered conductors of the distribution line.

[0137] In actual application scenarios, an intelligent ice melting device is connected under power outage conditions to build a controllable short-circuit ice melting circuit. By dynamically calculating the critical ice melting current threshold under different environmental parameter combinations, adaptive and precise ice melting of ice-covered conductors can be achieved. Figure 3 Figure 1 shows a schematic diagram of the cross-sectional structure of an elliptical ice-covered conductor. The system includes the ice layer Q1, the conductor body Q2, and the conductor interior Q3. When a critical ice-melting current is applied, the Joule heat generated inside the conductor is transferred to the ice layer through heat conduction. At the same time, a composite heat transfer process of radiation and convection is formed at the boundary Γ01 on the outer surface of the ice layer. Before the onset of phase change, the conductor-ice layer interface always maintains a thermodynamic equilibrium state (i.e., the conductor surface temperature T c = ice surface temperature T in =0℃), this ice melting mechanism based on internal heat source conduction makes the ice layer present a unique phase change feature of gradually melting from the inner surface to the outside.

[0138] As can be seen, in the above scheme, the structural characteristic parameters and environmental operating parameters of ice-covered conductors are collected in real time to accurately calculate the comprehensive heat transfer coefficient between the outer surface of the ice layer and the air medium. Based on the principle of thermodynamic equilibrium, a dynamic heat balance control model is established. Based on this model, the dynamic characteristics of the conductors, real-time environmental data, and the heat transfer coefficient field are deeply integrated to accurately solve the critical ice melting current, effectively eliminating the risks of under-melting or over-melting, improving ice melting efficiency while ensuring the safe and reliable operation of the distribution line.

[0139] In one embodiment of the present application, a method for calculating critical current of a distribution network line conductor based on environmental conditions is provided, which specifically includes the following steps:

[0140] The heat of melting ice on the conductor comes from Joule heat, that is:

[0141] q j =I 2 R T ; (1)

[0142] Among them, q jis the Joule heat flow, in W; I is the wire current; R T It is the resistivity of the conductor at ambient temperature, in Ω / m.

[0143] On the surface of the conductor (i.e. Figure 3 Γ13), the Joule heat is conducted through the ice layer to the outer surface of the ice layer ( Figure 3 Γ01), that is:

[0144]

[0145] Where I is the conductor current; R T is the conductor resistivity at ambient temperature; T in is the surface temperature of the ice layer; T i (θ) is the outer surface temperature of the ice layer corresponding to the contact angle θ between the ice layer and the wire, in degrees Celsius; R q (θ) is the thermal resistance of the ice layer corresponding to the micro-angle element d(θ), and the unit is W / (m.℃); d(θ) is the micro-angle element.

[0146] For an elliptical ice-covered conductor, due to the uneven thickness of the ice layer, Ti(θ) and Rq(θ) are both functions of θ.

[0147] On the outer surface of the ice layer, the heat lost through convection and radiation is:

[0148]

[0149] Among them, q i is the heat loss value of the outer surface of the ice layer, h is the heat exchange coefficient between the outer surface of the ice layer and the air environment; T i (θ) is the outer surface temperature of the ice layer at the contact angle θ between the ice layer and the conductor; T a is the ambient temperature; r c is the wire radius; d i (θ) is the ice thickness at angle θ; dθ is the micro-angle element.

[0150] The heat transfer coefficient between the outer surface of the ice layer and the air environment can be expressed as:

[0151] h=h c +h r ; (4)

[0152] Among them, h c is the convection heat transfer coefficient of the outer surface of the ice layer, in W / (m2.℃); hr is the radiation heat transfer coefficient of the outer surface of the ice layer, in W / (m2.℃).

[0153] h c and h r They can be expressed as:

[0154]

[0155] Where ε is the emissivity of the outer surface of the ice layer, ε = 0.9; σ is the radiation constant, σ = 5.67 × 10-8 W / m2.℃; λ a is the thermal conductivity of air, in W / (m.℃); Nu n 、Nu f The Nusselt numbers, which represent the natural convection and forced convection characteristics of ice-covered conductors, are calculated as follows:

[0156]

[0157] Among them, Pr, Gr, Re are Prandlt number, Grashof number and Reynolds number respectively, and their calculation formulas are:

[0158]

[0159] Where g is the gravity constant, g = 9.8m / s2; ν is the kinematic viscosity of air, ν = 1.328×10-5m2 / s; μ is the dynamic viscosity coefficient of air, μ = 1.72×10-5kg / (ms); C a is the specific heat capacity of air, C a =1005J / kg·℃;ρ a is the air density, ρ a =1.293kg / m3;v a is the wind speed, in m / s; d i is the ice thickness. For elliptical ice-covered conductors, r eq -r c Approximately replace d i , unit is m.

[0160] Optionally, in formula (6): B and b are coefficients determined by Gr, and under ice-covered environment conditions of the transmission line, 1.43×104≤Gr≤5.67×108, B=0.48, b=0.25; C and n are coefficients determined by Reynolds (Re) number.

[0161] Joule heat melting ice must meet two conditions at the same time: (1) the surface temperature of the ice layer reaches the melting point, that is, T in = 0℃; (2) The Joule heat is greater than the heat loss from the outer surface of the ice layer, that is, q j >q i The ice melting conditions and their corresponding ice melting states are shown in Table 2.

[0162] Table 2

[0163] Ice melting conditions Melting state <![CDATA[T in <0℃]]> Cannot melt <![CDATA[T in =0℃;q j <q i ]]> Cannot melt <![CDATA[T in =0℃;q j >q i ]]> Energy Integration <![CDATA[T in =0℃;q j =q i ]]> Critical melting state

[0164] It can be seen from Table 2 that when the inner surface temperature of the ice layer is T in = 0℃, and when the Joule heat is exactly equal to the heat loss on the outer surface of the ice layer, the ice layer will be in a critical state between melting and not melting. Let the critical melting current be I c According to formulas (2) and (3), the heat balance equation of the critical state is:

[0165]

[0166] For elliptical or eccentric circular iced conductors, due to the ice thickness d i is a function of θ, r i 、R q 、T i They are all functions of θ, and it is difficult to obtain the analytical solution of equation (8). Therefore, the ice flatness (used to describe the ellipticity of the ice-covered conductor) δ = 0 and the ice eccentricity (used to describe the degree to which the conductor deviates from the center of the ice layer) ζ = 0 are set, so that the ice-covered conductor is an unbiased circular ice-covered conductor. i is a constant, r i 、R q It is also a constant, the thermal resistance of the cylindrical ice layer R q It can be expressed as:

[0167]

[0168] Among them, λ Q1 is the thermal conductivity of the ice layer, λ Q1 =2.22W / (m.℃); r i is the radius of the ice-covered conductor, in meters.

[0169] Substituting formula (9) into formula (8) yields:

[0170]

[0171] The outer surface temperature of the ice layer T can be obtained by formula (10): i for:

[0172]

[0173] When δ = 0 and ζ = 0, formula (2) can be expressed as:

[0174]

[0175] Among them, I c is the critical ice melting current, in A.

[0176] Substituting formula (11) into formula (12), the critical ice melting current when δ = 0 and ζ = 0 can be obtained as:

[0177]

[0178] For formula (13), only when the ambient temperature T a ≤0℃, there is a real number solution, that is, only when T a When the temperature is less than 0℃, the critical ice melting current will exist. a When the temperature is >0℃, there is no critical ice melting current.

[0179] When the conductor ice is a non-deflected circular ice (i.e., when δ = 0, ζ = 0), the critical ice melting current I can be obtained according to formulas (4)-(7) and (13): c .

[0180] Based on the above content, we can know that the factors affecting the critical ice melting current of ice-covered conductors are wind speed (v a ), ambient temperature (T a ) and ice thickness (d i In addition, from formula (11), we can know that the wind speed (v a ), ambient temperature (T a ) and ice thickness (d i ) also affects the outer surface temperature of the ice layer (T i ) has an impact.

[0181] Furthermore, based on the calculation results of formulas (11) and (13), the influence of wind speed on the ice surface temperature and critical ice-melting current can be summarized as follows: 1) The ice surface temperature is negatively correlated with wind speed, and this cooling effect shows a clear nonlinear saturation characteristic as wind speed increases; 2) The critical ice-melting current is positively correlated with wind speed, and its growth trend also shows a characteristic of gradual saturation. Specifically, when the wind speed exceeds the critical value, its influence on both parameters gradually weakens.

[0182] Furthermore, based on the calculation results of formulas (11) and (13), the influence of ambient temperature on the thermodynamic parameters of the ice layer can be expressed as follows: 1) The ice layer surface temperature and the ambient temperature are significantly positively linearly correlated; 2) The critical ice melting current is negatively correlated with the ambient temperature, and this effect exhibits a clear nonlinear characteristic—when the ambient temperature is below a certain threshold, its current regulation effect gradually weakens and tends to saturation. Specifically, the increase in the critical ice melting current caused by a 1°C decrease in ambient temperature decreases as the temperature decreases.

[0183] Furthermore, based on the calculation results of formula (11) and formula (13), the influence of ice thickness on the thermodynamic parameters of the system is as follows: 1) the surface temperature of the ice layer is negatively correlated with the thickness; 2) the critical ice melting current shows only a weak positive correlation with the increase of ice thickness. This phenomenon is due to the dual antagonistic effect of ice thickness on thermal balance: the positive effect is reflected in the ice radius r i The increase in ice thickness leads to an increase in heat transfer area, thereby increasing surface heat loss; the reverse effect is that the thickening of the ice layer causes the outer surface temperature to approach the ambient temperature, resulting in a decrease in radiation and convection heat transfer. The mutual cancellation of these two competing mechanisms ultimately makes the effect of ice thickness on the critical ice melting current show a weak sensitivity. Figure 4 The figure shows the relationship between the thickness of the ice layer and the temperature of the outer surface of the ice layer. a =-5℃, wind speed v a =5m / s), the relationship between the ice layer thickness and the outer surface temperature of the ice layer for four different types of conductors (JTMII-120, CTMII-150, LGI-400, LGI-240). The vertical axis in the figure is the outer surface temperature of the ice layer (unit: ℃), and the horizontal axis is the ice layer thickness. The figure shows that the outer surface temperature of the ice layer of all conductor types decreases with the increase of ice layer thickness, showing a clear negative correlation. Further, as Figure 5 The figure shows the relationship between ice thickness and critical ice melting current. a =5℃, wind speed v a =5m / s). The figure shows the effect of ice thickness on the critical ice-melting current for four conductor types (LGJ-400, LGJ-240, CTMH-150, and JTMH-120). The vertical axis represents the critical ice-melting current, and the horizontal axis represents ice thickness. The figure shows that the critical ice-melting current increases monotonically with increasing ice thickness for all conductor types.

[0184] The embodiment of the present application realizes adaptive and precise control of critical ice melting under complex environmental conditions by constructing a dynamic ice melting model integrating multiple physical fields, thereby significantly improving the ice melting efficiency and safety under different icing conditions.

[0185] In one embodiment, a device for calculating the critical ice melting current of a distribution line conductor is provided. The device for calculating the critical ice melting current of a distribution line conductor corresponds one-to-one to the method for calculating the critical ice melting current of a distribution line conductor in the above embodiment. Figure 6 As shown, the distribution line conductor critical ice melting current calculation device 100 includes: an acquisition module 101, a construction module 102, a determination module 103 and a calculation module 104. The functional modules are described in detail as follows:

[0186] An acquisition module 101 is configured to acquire a first parameter of an ice-covered conductor of a power distribution line and a second parameter of an air environment in a target application environment;

[0187] A construction module 102 is used to establish a thermal balance control model for ice-covered conductors under critical ice melting conditions;

[0188] A determination module 103 is configured to determine a heat transfer coefficient between an outer surface of the ice layer of the ice-covered conductor and an air environment based on the first parameter and the second parameter;

[0189] The calculation module 104 is used to import the heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment, the first parameter and the second parameter into the heat balance control model to solve the critical ice melting current of the ice-covered conductor.

[0190] In one embodiment, the construction module 102 is specifically configured to:

[0191] Establish a Joule heat calculation model;

[0192] The Joule heat calculation model is:

[0193]

[0194] Where I is the conductor current; R T is the conductor resistivity at T degrees Celsius; T in is the surface temperature of the ice layer; T i (θ) is the outer surface temperature of the ice layer corresponding to the contact angle θ between the ice layer and the wire; R q (θ) is the thermal resistance of the ice layer corresponding to the micro-angle element d(θ); d(θ) is the micro-angle element;

[0195] Establish a calculation model for the heat loss value on the outer surface of the ice layer;

[0196] The calculation model of heat loss value on the outer surface of the ice layer is:

[0197] q i =∫0 2π h[T i (θ)-T a ]×[r c +d i (θ)]dθ;

[0198] Among them, q i is the heat loss value of the outer surface of the ice layer; h is the heat exchange coefficient between the outer surface of the ice layer and the air environment; T i (θ) is the outer surface temperature of the ice layer at the contact angle θ between the ice layer and the wire; T a is the ambient temperature; r c is the wire radius; d i (θ) is the ice thickness at the contact angle θ between the ice layer and the wire; dθ is the micro-angle element;

[0199] The critical ice melting conditions are: the cross section of the ice-covered conductor is an ideal circle, the inner surface temperature of the ice layer is 0 degrees Celsius, and the Joule heat power and the heat dissipation power of the outer surface of the ice layer reach a dynamic equilibrium;

[0200] Combine the Joule heat calculation model and the ice layer outer surface heat loss calculation model to establish the heat balance control equation of the heat balance control model;

[0201] The heat balance governing equation is:

[0202]

[0203] In one embodiment, the determination module 103 is specifically configured to:

[0204] Establishing a dimensionless calculation model, importing the first parameter and the second parameter into the dimensionless calculation model, and solving the dimensionless number, wherein the dimensionless number includes: Lagashov number, Prandtl number, and Reynolds number;

[0205] Based on dimensionless numbers, the first Nusselt number of ice-covered conductors under natural convection conditions and the second Nusselt number of ice-covered conductors under forced convection conditions are determined.

[0206] A heat transfer coefficient between an outer surface of an ice layer of an ice-covered conductor and an air environment is determined based on the dimensionless number, the first Nusselt number, the second Nusselt number, the first parameter, and the second parameter.

[0207] In one embodiment, the determination module 103 is further configured to:

[0208] A first Nusselt calculation model for ice-covered conductors under natural convection conditions is established. The Grashof number and Prandtl number are introduced into the first Nusselt calculation model to calculate the first Nusselt number of ice-covered conductors under natural convection conditions.

[0209] The first Nusselt calculation model is:

[0210] Nu n =B×(Gr×Pr) b ;

[0211] Among them, Nu n is the first Nusselt number; B is a constant; Gr is the Grashof number; Pr is the Prandtl number; b is a constant;

[0212] determining a first convection coefficient and a second convection coefficient based on the Reynolds number;

[0213] A second Nusselt calculation model for ice-covered conductors under forced convection conditions was established. The Reynolds number, Prandtl number, first convection coefficient, and second convection coefficient were imported into the second Nusselt calculation model to calculate the second Nusselt number of ice-covered conductors under forced convection conditions.

[0214] The second Nusselt calculation model is:

[0215]

[0216] Among them, Nu f is the second Nusselt number; C is the first convection coefficient; Re is the Reynolds number; n is the second convection coefficient; Pr is the Prandtl number.

[0217] In one embodiment, the determination module 103 is further configured to:

[0218] A calculation model for the convective heat transfer coefficient of the ice layer on the surface of an ice-covered conductor is established. The equivalent ice-covered conductor radius, air thermal conductivity, ice layer thickness, first Nusselt number, and second Nusselt number corresponding to an equivalent circular cross-section of the ice-covered conductor are introduced into the calculation model to calculate the convective heat transfer coefficient of the ice layer on the surface of the ice-covered conductor.

[0219] The calculation model of the convective heat transfer coefficient of the ice layer on the surface of the ice-covered conductor is:

[0220]

[0221] Among them, h c is the convection heat transfer coefficient on the outer surface of the ice layer; a is the thermal conductivity of air; Nu n is the first Nusselt number; Nu f is the second Nusselt number; r eq d is the equivalent ice-covered conductor radius corresponding to the equivalent circular cross-section of the ice-covered conductor; i is the thickness of the ice layer;

[0222] Establish a calculation model for the radiation heat transfer coefficient of the outer surface of the ice layer, import the emissivity of the outer surface of the ice layer and the ambient temperature into the calculation model of the radiation heat transfer coefficient of the outer surface of the ice layer, and solve the radiation heat transfer coefficient of the outer surface of the ice layer;

[0223] The calculation model of the radiation heat transfer coefficient of the outer surface of the ice layer is:

[0224] h r =4εσ(T a +273.15) 3 ;

[0225] Among them, h r is the radiation heat transfer coefficient of the outer surface of the ice layer; ε is the emissivity of the outer surface of the ice layer; σ is the radiation constant; T a is the ambient temperature;

[0226] The heat transfer coefficient between the outer surface of the ice layer and the air environment is obtained by adding the convection heat transfer coefficient of the outer surface of the ice layer and the radiation heat transfer coefficient of the outer surface of the ice layer.

[0227] In one embodiment, the calculation module 104 is specifically configured to:

[0228] The ice layer thermal resistance expression is established as:

[0229]

[0230] Among them, R q is the thermal resistance of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; λ Q1 is the thermal conductivity of the ice layer;

[0231] Substituting the ice layer thermal resistance expression into the heat balance control equation, the calculation model of the ice layer outer surface temperature is obtained:

[0232]

[0233] Among them, T i is the outer surface temperature of the ice layer; Q1 is the thermal conductivity of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; h is the heat transfer coefficient between the outer surface of the ice layer and the air environment; T a is the ambient temperature;

[0234] Substituting the ice layer outer surface temperature calculation model into the Joule heat calculation model, the critical ice melting current calculation model is obtained;

[0235] The critical ice melting current calculation model is:

[0236]

[0237] Among them, I c is the critical ice melting current; Q1 is the thermal conductivity of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; h is the heat transfer coefficient between the outer surface of the ice layer and the air environment; T a is the ambient temperature; R t is the conductor resistivity at ambient temperature;

[0238] The first parameter, the second parameter, and the heat transfer coefficient between the outer surface of the ice layer and the air environment are introduced into the critical ice melting current calculation model to solve the critical ice melting current of the ice-covered conductor.

[0239] In one embodiment, the apparatus further comprises:

[0240] The processing module is used to melt ice-covered conductors of the distribution line by using a short-circuit conductor current ice melting technology based on a critical ice melting current.

[0241] The present invention provides a device 100 for calculating the critical ice-melting current of distribution line conductors. This device accurately calculates the comprehensive heat transfer coefficient between the outer surface of the ice layer and the air medium by collecting structural characteristic parameters and environmental operating condition parameters of ice-covered conductors in real time. Based on the principle of thermodynamic equilibrium, a dynamic heat balance control model is established. This model deeply integrates the dynamic characteristics of the conductors, real-time environmental data, and the heat transfer coefficient field to accurately determine the critical ice-melting current, effectively eliminating the risks of under-melting or over-melting, improving ice-melting efficiency while ensuring the safe and reliable operation of distribution lines.

[0242] The specific limitations of the distribution line conductor critical ice-melting current calculation device can be found in the limitations of the distribution line conductor critical ice-melting current calculation method described above and will not be further elaborated here. Each module within the aforementioned distribution line conductor critical ice-melting current calculation device can be implemented in whole or in part via software, hardware, or a combination thereof. Each of these modules can be embedded in or independent of a processor within an electronic device in hardware form, or stored in memory within the electronic device in software form, allowing the processor to invoke and execute the corresponding operations of each module.

[0243] In one embodiment, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the following steps are performed:

[0244] Obtaining a first parameter of an ice-covered conductor of a distribution line under a target application environment and a second parameter of an air environment;

[0245] Establish a thermal balance control model for ice-covered conductors under critical ice melting conditions;

[0246] Determining a heat transfer coefficient between an outer surface of an ice layer of the ice-covered conductor and an air environment based on the first parameter and the second parameter;

[0247] The heat transfer coefficient, the first parameter and the second parameter between the outer surface of the ice layer of the ice-covered conductor and the air environment are introduced into the thermal balance control model to solve the critical ice melting current of the ice-covered conductor.

[0248] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0249] Obtaining a first parameter of an ice-covered conductor of a distribution line under a target application environment and a second parameter of an air environment;

[0250] Establish a thermal balance control model for ice-covered conductors under critical ice melting conditions;

[0251] Determining a heat transfer coefficient between an outer surface of an ice layer of the ice-covered conductor and an air environment based on the first parameter and the second parameter;

[0252] The heat transfer coefficient, the first parameter and the second parameter between the outer surface of the ice layer of the ice-covered conductor and the air environment are introduced into the thermal balance control model to solve the critical ice melting current of the ice-covered conductor.

[0253] It should be noted that the above functions or steps that can be implemented by the computer-readable storage medium or electronic device can be referred to the relevant descriptions on the server side and the client side in the aforementioned method embodiment. To avoid repetition, they will not be described one by one here.

[0254] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0255] Those skilled in the art will clearly understand that for the sake of convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0256] The embodiments described above 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. 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 various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method for calculating the critical ice melting current of distribution network line conductors, characterized in that: include: Obtaining a first parameter of an ice-covered conductor of a distribution line under a target application environment and a second parameter of an air environment; Establishing a thermal balance control model for the ice-covered conductor under critical ice melting conditions; determining a heat transfer coefficient between an outer surface of the ice layer of the ice-covered conductor and an air environment based on the first parameter and the second parameter; The heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment, the first parameter, and the second parameter are introduced into the heat balance control model to solve the critical ice melting current of the ice-covered conductor.

2. The method according to claim 1, characterized in that The step of establishing a thermal balance control model for the ice-covered conductor under critical ice melting conditions specifically includes: Establish a Joule heat calculation model; The Joule heat calculation model is: Where I is the conductor current; R T is the conductor resistivity at T degrees Celsius; T in is the surface temperature of the ice layer; T i (θ) is the outer surface temperature of the ice layer corresponding to the contact angle θ between the ice layer and the wire; R q (θ) is the thermal resistance of the ice layer corresponding to the micro-angle element d(θ); d(θ) is the micro-angle element; Establish a calculation model for the heat loss value on the outer surface of the ice layer; The calculation model for the heat loss value on the outer surface of the ice layer is: q i =∫0 2π h[T i (θ)-T a ]×[r c +d i (θ)]dθ; Among them, q i is the heat loss value of the outer surface of the ice layer; h is the heat exchange coefficient between the outer surface of the ice layer and the air environment; T i (θ) is the outer surface temperature of the ice layer at the contact angle θ between the ice layer and the wire; T a is the ambient temperature; r c is the wire radius; d i (θ) is the ice thickness at the contact angle θ between the ice layer and the wire; dθ is the micro-angle element; Assume that the critical ice melting conditions are: the cross-section of the ice-covered conductor is an ideal circle, the inner surface temperature of the ice layer is 0 degrees Celsius, and the Joule heat power and the heat dissipation power of the outer surface of the ice layer reach a dynamic equilibrium; The Joule heat calculation model and the ice layer outer surface heat loss value calculation model are combined to establish a heat balance control equation of a heat balance control model; The heat balance control equation is:

3. The method according to claim 1, characterized in that The step of determining the heat exchange coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment based on the first parameter and the second parameter specifically includes: Establishing a dimensionless calculation model, importing the first parameter and the second parameter into the dimensionless calculation model, and solving dimensionless numbers, wherein the dimensionless numbers include: Lagashov number, Prandtl number, and Reynolds number; Determining, based on the dimensionless number, a first Nusselt number of the ice-covered conductor under natural convection conditions and a second Nusselt number of the ice-covered conductor under forced convection conditions; A heat transfer coefficient between an outer surface of the ice layer of the ice-covered conductor and an air environment is determined based on the dimensionless number, the first Nusselt number, the second Nusselt number, the first parameter, and the second parameter.

4. The method according to claim 3, characterized in that The step of determining a first Nusselt number of the ice-covered conductor under natural convection conditions and a second Nusselt number of the ice-covered conductor under forced convection conditions based on the dimensionless number specifically includes: establishing a first Nusselt calculation model for an ice-covered conductor under natural convection conditions, importing the Grashof number and the Prandtl number into the first Nusselt calculation model, and solving for the first Nusselt number of the ice-covered conductor under natural convection conditions; The first Nusselt calculation model is: Not n =B×(Gr×Pr) b ; Among them, Nu n is the first Nusselt number; B is a constant; Gr is the Grashof number; Pr is the Prandtl number; b is a constant; determining a first convection coefficient and a second convection coefficient based on the Reynolds number; establishing a second Nusselt calculation model for the ice-covered conductor under forced convection conditions, importing the Reynolds number, the Prandtl number, the first convection coefficient, and the second convection coefficient into the second Nusselt calculation model, and solving for the second Nusselt number of the ice-covered conductor under forced convection conditions; The second Nusselt calculation model is: Among them, Nu f is the second Nusselt number; C is the first convection coefficient; Re is the Reynolds number; n is the second convection coefficient; Pr is the Prandtl number.

5. The method according to claim 3, characterized in that The step of determining the heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment based on the dimensionless number, the first Nusselt number, the second Nusselt number, the first parameter, and the second parameter specifically includes: Establish a calculation model for the convective heat transfer coefficient of the ice layer on the surface of the ice-covered conductor, import the equivalent ice-covered conductor radius, air thermal conductivity, ice layer thickness, first Nusselt number, and second Nusselt number corresponding to the ice-covered conductor's ice-covered cross-section being an equivalent circular cross-section into the calculation model to solve for the convective heat transfer coefficient of the ice layer on the surface of the ice-covered conductor; The calculation model of the convective heat transfer coefficient of the ice layer on the surface of the ice-covered conductor is: Among them, h c is the convection heat transfer coefficient on the outer surface of the ice layer; a is the thermal conductivity of air; Nu n is the first Nusselt number; Nu f is the second Nusselt number; r eq d is the equivalent ice-covered conductor radius corresponding to the equivalent circular cross-section of the ice-covered conductor; i is the thickness of the ice layer; Establishing a calculation model for the radiation heat transfer coefficient of the outer surface of the ice layer, importing the emissivity of the outer surface of the ice layer and the ambient temperature into the calculation model for the radiation heat transfer coefficient of the outer surface of the ice layer, and solving the radiation heat transfer coefficient of the outer surface of the ice layer; The calculation model of the radiation heat transfer coefficient of the outer surface of the ice layer is: h r =4εσ(T a +273.15) 3 ; Among them, h r is the radiation heat transfer coefficient of the outer surface of the ice layer; ε is the emissivity of the outer surface of the ice layer; σ is the radiation constant; T a is the ambient temperature; The heat transfer coefficient between the outer surface of the ice layer and the air environment is obtained by adding the convection heat transfer coefficient of the outer surface of the ice layer and the radiation heat transfer coefficient of the outer surface of the ice layer.

6. The method according to claim 1, characterized in that The step of importing the heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment, the first parameter, and the second parameter into the heat balance control model to solve the critical ice melting current of the ice-covered conductor specifically includes: The ice layer thermal resistance expression is established as: Among them, R q is the thermal resistance of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; λ Q1 is the thermal conductivity of the ice layer; Substituting the ice layer thermal resistance expression into the heat balance control equation, the calculation model of the ice layer outer surface temperature is obtained: Among them, T i is the outer surface temperature of the ice layer; Q1 is the thermal conductivity of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; h is the heat transfer coefficient between the outer surface of the ice layer and the air environment; T a is the ambient temperature; Substituting the ice layer outer surface temperature calculation model into the Joule heat calculation model to obtain the critical ice melting current calculation model; The critical ice melting current calculation model is: Among them, I c is the critical ice melting current; Q1 is the thermal conductivity of the ice layer; r i is the radius of the ice-covered conductor; r c is the wire radius; h is the heat transfer coefficient between the outer surface of the ice layer and the air environment; T a is the ambient temperature; R T is the conductor resistivity at ambient temperature; The first parameter, the second parameter, and the heat exchange coefficient between the outer surface of the ice layer and the air environment are introduced into the critical ice melting current calculation model to solve the critical ice melting current of the ice-covered conductor.

7. The method according to any one of claims 1 to 6, characterized in that After importing the heat transfer coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment, the first parameter, and the second parameter into the heat balance control model to solve the critical ice melting current of the ice-covered conductor, the method further includes: Based on the critical ice melting current, the short-circuit conductor current ice melting technology is used to melt the ice-covered conductors of the distribution lines.

8. A device for calculating the critical ice melting current of distribution network line conductors, characterized in that: include: An acquisition module, configured to acquire a first parameter of an ice-covered conductor of a power distribution line in a target application environment and a second parameter of an air environment; A construction module is used to establish a thermal balance control model of the ice-covered conductor under critical ice melting conditions; a determination module, configured to determine a heat transfer coefficient between an outer surface of the ice layer of the ice-covered conductor and an air environment based on the first parameter and the second parameter; A calculation module is used to import the heat exchange coefficient between the outer surface of the ice layer of the ice-covered conductor and the air environment, the first parameter and the second parameter into the thermal balance control model to solve the critical ice melting current of the ice-covered conductor.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method for calculating the critical ice melting current of a distribution network line conductor are implemented as claimed in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for calculating the critical ice melting current of a distribution network line conductor are implemented as claimed in any one of claims 1 to 7.

Images