Line current-carrying capacity calculation method, system, equipment, medium and product

Abstract

The invention relates to the technical field of power lines, and discloses a line current-carrying capacity calculation method, system and device, a medium and a product, and the method comprises the steps: constructing an equivalent circuit model of a target line, thereby precisely quantifying the current distribution of the target line, determining the current distribution of each layer of conductor of the target line through the equivalent circuit model, and calculating the current-carrying capacity of the target line. The alternating current resistance of the target line is determined according to the current distribution of each layer of conductor, interpolation fitting is carried out on the current distribution and the alternating current resistance of each layer of conductor under different working conditions to obtain a continuous function relationship, a heat balance equation of the target line is constructed, and the target line is obtained according to the heat balance equation and the continuous function relationship. And the maximum current-carrying capacity of the target line is determined, so that the accuracy of the current-carrying capacity calculation method is improved, and the deviation between the current-carrying capacity calculation value and the actual value is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power lines, and in particular to a method, system, equipment, medium and product for calculating line current carrying capacity. Background Art

[0002] Ampacity is one of the key parameters determining the safe and stable operation of power lines. Accurately calculating line ampacity is crucial for ensuring the safety and stability of power grids. With rising global energy demand and the large-scale integration of renewable energy, transmission lines are often required to operate near their thermal limits, placing stringent demands on the accuracy of ampacity calculations.

[0003] At present, the accuracy of traditional current-carrying capacity calculation methods is poor, resulting in a large deviation between the calculated current-carrying capacity and the actual value. Summary of the Invention

[0004] In view of this, the present invention provides a method, system, device, medium and product for calculating line current carrying capacity, which solves the technical problem that the traditional current carrying capacity calculation method has poor accuracy, resulting in a large deviation between the calculated current carrying capacity value and the actual value.

[0005] A first aspect of the present invention provides a method for calculating line current carrying capacity, comprising:

[0006] constructing an equivalent circuit model of the target circuit according to structural parameters of the target circuit;

[0007] Determining the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determining the AC resistance of the target circuit according to the current distribution of each layer of conductors;

[0008] Performing interpolation fitting on the current distribution of the conductors in each layer and the AC resistance under different working conditions to obtain a continuous function relationship;

[0009] A heat balance equation for the target circuit is constructed, and a maximum current carrying capacity of the target circuit is determined based on the heat balance equation and the continuous function relationship.

[0010] Preferably, constructing an equivalent circuit model of the target circuit according to the structural parameters of the target circuit includes:

[0011] Acquiring structural parameters of the target circuit;

[0012] Based on Kirchhoff's voltage law, construct equivalent circuit equations for each layer of the target circuit according to the structural parameters of the target circuit;

[0013] An equivalent circuit model of the target circuit is determined according to the equivalent circuit equations of each layer of the target circuit.

[0014] Preferably, the target line is a single-layer aluminum conductor;

[0015] Accordingly, determining the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determining the AC resistance of the target circuit according to the current distribution of each layer of conductors, includes:

[0016] Determining the current magnetic field strength of each layer of conductors based on the current current distribution of each layer of conductors in the equivalent circuit model;

[0017] Correcting the current magnetic field strength of each layer of conductors according to the twist pitch parameter to obtain corrected magnetic field strength of each layer of conductors;

[0018] Updating the equivalent circuit model using the corrected magnetic field strength of each layer of conductor to obtain an updated equivalent circuit model;

[0019] Determining the current distribution of conductors in each layer after current update according to the updated equivalent circuit model;

[0020] Determining whether the current distribution of the conductors in each layer after the current update has reached a preset convergence condition;

[0021] If it is determined that the currently updated current distribution of the conductors of each layer does not meet the preset convergence condition, updating the currently updated current distribution of the conductors of each layer to the current current distribution of the conductors of each layer, switching to the current current distribution of the conductors of each layer according to the equivalent circuit model, determining the current magnetic field strength of the conductors of each layer, until it is determined that the currently updated current distribution of the conductors of each layer meets the preset convergence condition, and outputting the final current distribution of the conductors of each layer;

[0022] Determining the final magnetic field strength of each layer of the target circuit according to the current distribution of each layer of conductor of the target circuit;

[0023] The AC resistance of the target circuit is determined according to the final magnetic field strength of each layer of the target circuit.

[0024] Preferably, the target circuit is a three-layer aluminum conductor;

[0025] Accordingly, determining the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determining the AC resistance of the target circuit according to the current distribution of each layer of conductors, includes:

[0026] Constructing nonlinear equations corresponding to the conductors of each layer according to the equivalent circuit model, and determining a nonlinear equation group of the target circuit according to the nonlinear equations corresponding to the conductors of each layer;

[0027] linearizing the nonlinear equations using a Newton iteration method, and determining a solution to the nonlinear equations to obtain a current distribution of each layer of conductors of the target circuit;

[0028] Determining the final magnetic field strength of each layer of the target circuit according to the current distribution of each layer of conductor of the target circuit;

[0029] The AC resistance of the target circuit is determined according to the final magnetic field strength of each layer of the target circuit.

[0030] Preferably, performing interpolation fitting on the current distribution of the conductors in each layer and the AC resistance under different working conditions to obtain a continuous function relationship includes:

[0031] Obtaining the current distribution of the conductors in each layer and the AC resistance under different working conditions to construct a discrete data set;

[0032] A cubic spline interpolation algorithm is used to perform parameter fitting on the discrete data set to obtain the continuous function relationship; wherein the continuous function relationship is used to characterize the mapping relationship between the current distribution and the AC resistance.

[0033] Preferably, constructing a heat balance equation for the target circuit and determining the maximum current carrying capacity of the target circuit according to the heat balance equation and the continuous function relationship includes:

[0034] Acquiring environmental parameters of the target line, and determining Joule heat of solar radiation absorption, Joule heat of conductor radiation dissipation, and Joule heat of conductor convection dissipation of the target line according to the environmental parameters;

[0035] The Joule heat of the conductor resistance of the target circuit is determined according to the continuous function relationship by the following formula; wherein the Joule heat of the conductor resistance is:

[0036]

[0037] Where, is the Joule heat of the wire resistance, is a continuous function relationship, is the maximum current carrying capacity;

[0038] A heat balance equation for the target circuit is constructed based on the Joule heat absorbed by solar radiation, the Joule heat dissipated by radiation of the conductor, the Joule heat dissipated by convection of the conductor, and the Joule heat of resistance of the conductor. The heat balance equation is solved to obtain the maximum current carrying capacity of the target circuit.

[0039] In a second aspect, the present invention further provides a line current carrying capacity calculation system, comprising:

[0040] An equivalent model building module, configured to build an equivalent circuit model of the target circuit according to structural parameters of the target circuit;

[0041] a resistance determination module, configured to determine the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determine the AC resistance of the target circuit according to the current distribution of each layer of conductors;

[0042] An interpolation fitting module, configured to perform interpolation fitting on the current distribution of the conductors in each layer and the AC resistance under different working conditions to obtain a continuous function relationship;

[0043] The current carrying capacity calculation module is used to construct a heat balance equation for the target circuit and determine the maximum current carrying capacity of the target circuit according to the heat balance equation and the continuous function relationship.

[0044] In a third aspect, the present invention further provides an electronic device comprising a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the line current carrying capacity calculation method as described in the first aspect.

[0045] In a fourth aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the steps of the line current carrying capacity calculation method as described in the first aspect.

[0046] In a fifth aspect, the present invention also provides a computer program product, comprising 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 executes the steps of the line current carrying capacity calculation method as described in the first aspect.

[0047] As can be seen from the above technical solutions, the present invention accurately quantifies the current distribution of the target circuit by constructing an equivalent circuit model of the target circuit, and determines the current distribution of each layer of conductors of the target circuit through the equivalent circuit model, and determines the AC resistance of the target circuit based on the current distribution of each layer of conductors. By interpolating and fitting the current distribution and AC resistance of each layer of conductors under different working conditions, a continuous function relationship is obtained, and a thermal balance equation of the target circuit is constructed. Based on the thermal balance equation and the continuous function relationship, the maximum current-carrying capacity of the target circuit is determined, thereby improving the accuracy of the current-carrying capacity calculation method and greatly reducing the deviation between the calculated current-carrying capacity and the actual value. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] 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.

[0049] Figure 1 A diagram illustrating an application environment of a line current carrying capacity calculation method provided by an embodiment of the present invention;

[0050] Figure 2 A flow chart of a method for calculating line current carrying capacity provided by an embodiment of the present invention;

[0051] Figure 3 A schematic structural diagram of a line current carrying capacity calculation system provided by an embodiment of the present invention;

[0052] Figure 4 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments 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 efforts shall fall within the scope of protection of the present invention.

[0054] The circuit current carrying capacity calculation method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. Among them, the terminal 101 communicates with the server 102 through the network. The data storage system can store the data that the server 102 needs to process. The data storage system can be integrated on the server 102, or it can be placed on the cloud or other network servers. The terminal 101 or the server 102 constructs an equivalent circuit model of the target line according to the structural parameters of the target line; determines the current distribution of each layer of conductors of the target line according to the equivalent circuit model, and determines the AC resistance of the target line according to the current distribution of each layer of conductors; interpolates and fits the current distribution and AC resistance of each layer of conductors under different working conditions to obtain a continuous function relationship; constructs the thermal balance equation of the target line, and determines the maximum current carrying capacity of the target line according to the thermal balance equation and the continuous function relationship.

[0055] The terminal 101 may be, but is not limited to, various personal computers, laptops, smart phones, tablet computers, and the like.

[0056] The server 102 may be an independent physical server, a server cluster or a distributed system composed of multiple physical servers, or a cloud server that provides cloud computing services.

[0057] like Figure 2 As shown, the embodiment of the present application provides a method for calculating the current carrying capacity of a line, and the method is applied to Figure 1 The terminal 101 or the server 102 in the example is used to illustrate the method, which includes the following steps S1 to S4.

[0058] Step S1: construct an equivalent circuit model of the target circuit according to the structural parameters of the target circuit.

[0059] Among them, the structural parameters of the target line include the outer diameter of the conductor, the geometric dimensions of the aluminum layer and steel core, the twist pitch, etc.

[0060] The equivalent circuit model of the target line is a mathematical model used to simulate the current distribution and resistance characteristics of the target line. Based on the actual structural parameters of the target line, such as the outer diameter of the conductor, the geometric dimensions of the aluminum layer and steel core, and the stranding pitch, this model accurately reflects the current flow and resistance changes in the line.

[0061] Step S2: determining the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determining the AC resistance of the target circuit according to the current distribution of each layer of conductors.

[0062] The current distribution of each conductor layer refers to the magnitude and direction of the current carried by conductors at different levels in the equivalent circuit model. Using this equivalent circuit model, the current distribution of each conductor layer can be accurately calculated, thereby determining the total impedance and AC resistance of the target line. AC resistance is the equivalent resistance after accounting for factors such as the skin effect and proximity effect caused by AC current in the conductor. It reflects the energy consumption characteristics of the line when transmitting AC power.

[0063] Step S3: performing interpolation fitting on the current distribution and AC resistance of each layer of conductors under different working conditions to obtain a continuous function relationship.

[0064] Operating conditions refer to the current distribution of each conductor layer under different currents, temperatures, and frequencies. Through interpolation fitting technology, we can transform discrete data points (i.e., the current distribution and AC resistance of each conductor layer under different operating conditions) into a continuous, smooth functional relationship. This functional relationship accurately describes the trends of current distribution and AC resistance as the operating conditions change. During the interpolation fitting process, we employ advanced algorithms, such as cubic spline interpolation, to ensure the accuracy and stability of the fitting results.

[0065] Step S4: construct a heat balance equation for the target circuit, and determine the maximum current carrying capacity of the target circuit based on the heat balance equation and the continuous function relationship.

[0066] Joule heating due to conductor resistance refers to the heat generated by the conductor's inherent resistance when current passes through it. When determining the target line's maximum current carrying capacity, this Joule heating factor is combined with the continuous function relationship derived through interpolation and fitting. This continuous function reflects the changing trends in the target line's current distribution and AC resistance under different operating conditions. By combining these two factors, we can more accurately assess the target line's heat dissipation when transmitting different currents, thereby determining the maximum current that can be carried while ensuring safe and stable operation.

[0067] It should be noted that the embodiment of the present application constructs an equivalent circuit model of the target circuit to accurately quantify the current distribution of the target circuit, and determines the current distribution of each layer of conductors of the target circuit through the equivalent circuit model, and determines the AC resistance of the target circuit based on the current distribution of each layer of conductors. By interpolating and fitting the current distribution and AC resistance of each layer of conductors under different working conditions, a continuous function relationship is obtained, and a thermal balance equation of the target circuit is constructed. According to the thermal balance equation and the continuous function relationship, the maximum current-carrying capacity of the target circuit is determined, thereby improving the accuracy of the current-carrying capacity calculation method and greatly reducing the deviation between the calculated current-carrying capacity and the actual value.

[0068] In some embodiments, constructing an equivalent circuit model of the target circuit according to structural parameters of the target circuit includes:

[0069] Step S101: Acquire structural parameters of a target circuit.

[0070] Among them, the target line is a steel core conductor, and the structural parameters include the outer diameter of the conductor, the geometric dimensions of the aluminum layer and the steel core, and the twist pitch.

[0071] Step S102 : Based on Kirchhoff's voltage law and according to the structural parameters of the target circuit, equivalent circuit equations of each layer of the target circuit are constructed.

[0072] Among them, the equivalent circuit equations of each layer of the target circuit are established by Kirchhoff's voltage law:

[0073]

[0074] Where V is the voltage, is the interlayer mutual inductance, is the angular frequency, is the k-th layer circuit current, is the resistance of the k-th layer circuit, is the self-inductance of the k-th layer circuit, j is the imaginary unit, It is the current of each circuit loop except the k layer, and is also the magnetizing current of the steel core.

[0075] The self-inductance element in the equivalent circuit captures the circumferential magnetic field distribution of the conductor, the mutual inductance element analyzes the cross-layer coupling effect of the axial magnetic field, the frequency-dependent impedance element dynamically tracks the current distribution offset caused by the skin effect, and the temperature coupling coefficient quantifies the temperature dependence of the steel core magnetization intensity. These four parameters respond in a coordinated manner through a multi-physics coupling framework, enabling coordinated dynamic modeling of magnetic field, conductivity, and thermodynamic properties.

[0076] Step S103: Determine the equivalent circuit model of the target circuit according to the equivalent circuit equations of each layer of the target circuit.

[0077] It can be understood that the embodiments of the present application can accurately reflect the current distribution and AC resistance characteristics of the target circuit under different working conditions by constructing an equivalent circuit model.

[0078] In some embodiments, the target line is a single layer aluminum conductor.

[0079] Single-layer aluminum conductors, with their outer layer made of aluminum, offer excellent conductivity and corrosion resistance. When constructing equivalent circuit models, special consideration must be given to the current distribution characteristics of the aluminum layer and the electromagnetic coupling between the aluminum layer and the inner conductor (such as the steel core). Accurately modeling these effects can further improve the accuracy of the equivalent circuit model, enabling more accurate calculation of the target line's maximum current carrying capacity. Furthermore, for single-layer aluminum conductors, attention must be paid to their heat dissipation under various operating conditions to ensure safe and stable line operation.

[0080] Accordingly, the current distribution of each layer of conductors of the target circuit is determined according to the equivalent circuit model, and the AC resistance of the target circuit is determined according to the current distribution of each layer of conductors, including:

[0081] Step S201: Determine the current magnetic field strength of each layer of conductors according to the current current distribution of each layer of conductors in the equivalent circuit model.

[0082] Among them, the longitudinal magnetic field strength of a single-layer aluminum stranded conductor is calculated by the following formula:

[0083]

[0084] Where, is the longitudinal magnetic field strength, is the radius of the steel core.

[0085] Step S202: Correct the current magnetic field strength of each layer of conductors according to the twist pitch parameter to obtain a corrected magnetic field strength of each layer of conductors.

[0086] The twist pitch parameter refers to the distance between two adjacent turns of a conductor during the twisting process. This parameter significantly affects the electromagnetic properties and current distribution of the conductor. By introducing the twist pitch parameter, the actual operating conditions of the conductor can be more accurately simulated, further improving the accuracy of the equivalent circuit model. The corrected magnetic field strength of each conductor layer can more realistically reflect the electromagnetic field distribution of the conductor under different operating conditions.

[0087] To compensate for this magnetic field cancellation effect, a magnetic flux attenuation factor is introduced into the equivalent circuit model. The magnetic flux attenuation factor is associated with the twist pitch parameter and is used to quantitatively correct the calculated longitudinal magnetic field strength. The magnetic flux attenuation factor is:

[0088]

[0089] in, is the flux attenuation factor, is the distance variable, is the characteristic attenuation length of the material.

[0090] in,

[0091]

[0092] Where, is the twist pitch, is the angular variable of magnetic field propagation.

[0093]

[0094] in, is the angular frequency ( ), is the magnetic permeability of the material, is the electrical conductivity of the material.

[0095] The current magnetic field strength of each layer of conductor is corrected by the magnetic flux attenuation factor, and the result is:

[0096]

[0097] Where, is the corrected longitudinal magnetic field strength.

[0098] Step S203: updating the equivalent circuit model using the corrected magnetic field strength of each layer of conductors to obtain an updated equivalent circuit model.

[0099] Among them, in the equivalent circuit model, the function Used to describe the effect of the corrected longitudinal magnetic field strength on the inductance and mutual inductance. The function can be expressed as:

[0100] For the self-inductance term:

[0101]

[0102] For the mutual inductance term:

[0103]

[0104] in, and It is the influence coefficient of specific wire model on inductance and mutual inductance.

[0105] The correction formulas for the inductance and mutual inductance terms in the equivalent circuit model are:

[0106] Self-inductive element:

[0107]

[0108] Mutual inductance element:

[0109]

[0110] in and are the reference self-inductance and mutual inductance respectively.

[0111] In addition, the steel core magnetizing current I is introduced into the equivalent circuit model. m As independent variables:

[0112]

[0113] in, is the steel core magnetic circuit length, take the conductor length. is the total current of the aluminum layer, is the coupling coefficient of the aluminum layer current to the steel core magnetic field (related to the twisting pitch and the number of layers).

[0114] Therefore, the corrected magnetic field strength is fed back to the equivalent circuit model to update the steel core magnetizing current, self-inductance and mutual inductance.

[0115] Step S204: Determine the current distribution of conductors in each layer after the current update based on the updated equivalent circuit model.

[0116] The updated equivalent circuit model allows for more accurate calculation of the current distribution within each conductor layer. This approach, based on the combined application of electromagnetic field theory and circuit theory, continuously updates and modifies the equivalent circuit model to more accurately reflect the physical characteristics of actual circuits, thereby improving the accuracy of current distribution calculations.

[0117] Step S205: Determine whether the current distribution of each layer of conductors after the current update has reached a preset convergence condition.

[0118] An iterative algorithm is used to solve the current distribution. The iteration process continues and repeats until the change in the current distribution falls below a pre-set threshold. At this point, the convergence condition is considered met and the iteration process terminates. This is achieved by comparing the difference between the current distributions calculated from two consecutive iterations. When this difference falls below a pre-set minimum, the current distribution is considered to have reached the pre-set convergence condition and no further iterations are performed.

[0119] Step S206: If it is determined that the currently updated current distribution of the conductors in each layer does not meet the preset convergence condition, the current current distribution of the conductors in each layer is updated using the currently updated current distribution of the conductors in each layer, and the current current distribution of the conductors in each layer is switched to the current current distribution of the conductors in each layer according to the equivalent circuit model to determine the current magnetic field strength of the conductors in each layer until it is determined that the currently updated current distribution of the conductors in each layer meets the preset convergence condition, and then the final current distribution of the conductors in each layer is output.

[0120] Step S207: Determine the final magnetic field strength of each layer of the target circuit according to the current distribution of each layer of conductors of the target circuit.

[0121] The current in each conductor layer satisfies Kirchhoff's current law, and the magnetic field strength of each layer is an important parameter reflecting the electromagnetic characteristics of the target line. When determining the magnetic field strength of each layer, the current distribution of each conductor layer, the geometric dimensions of the wire, and the electromagnetic characteristics of the material are comprehensively considered. The magnetic field strength of each layer is accurately calculated. The process of calculating the magnetic field strength of each layer is as follows:

[0122]

[0123] Step S208: Determine the AC resistance of the target circuit according to the final magnetic field strength of each layer of the target circuit.

[0124] The calculation formula for AC resistance is:

[0125]

[0126] in, is the AC resistance, is the DC resistance, is the temperature coefficient of resistance, is the temperature change, is the correlation coefficient with the longitudinal magnetic field strength.

[0127] In some embodiments, the target line is a three-layer aluminum conductor.

[0128] A three-layer aluminum conductor is composed of three layers of aluminum, each separated by insulating material. Compared to a single-layer aluminum conductor, a three-layer aluminum conductor has higher electrical conductivity and better heat dissipation capabilities. When constructing an equivalent circuit model, it is necessary to consider the current distribution characteristics of each layer of aluminum material and the electromagnetic coupling effect between the layers of aluminum material. Accordingly, the current distribution of each layer of conductor of the target circuit is determined based on the equivalent circuit model, and the AC resistance of the target circuit is determined based on the current distribution of each layer of conductor. This includes:

[0129] Step S211: construct nonlinear equations corresponding to each layer of conductors according to the equivalent circuit model, and determine the nonlinear equation group of the target circuit according to the nonlinear equations corresponding to each layer of conductors.

[0130] Among them, the nonlinear equation of each layer of conductor is established according to the equivalent circuit model:

[0131]

[0132] in, is the voltage of the kth layer, is the interlayer mutual inductance, is the angular frequency, is the k-th layer circuit current, is the resistance of the k-th layer circuit, is the self-inductance of the k-th layer circuit.

[0133] Among them, each layer of the wire corresponds to a nonlinear equation, wherein the nonlinear equation group includes the current variables and circuit parameters (resistance, inductance, mutual inductance, etc.) of the conductors of each layer, and each layer of the wire corresponds to a nonlinear equation to form a nonlinear equation group of the target line.

[0134] Step S212: linearize the nonlinear equations using the Newton iteration method, determine the solution of the nonlinear equations, and obtain the current distribution of each layer of conductors in the target circuit.

[0135] Here, the initial current value x (0) is set, and for the current current value, Compute the residual for each equation:

[0136]

[0137] in, Indicates the The equation in The residual error at iteration .

[0138] Determine whether the residual is zero. If the residual is zero, the current solution is used as the solution to the nonlinear circuit equations and the iteration is terminated. Otherwise, the Jacobian matrix of the nonlinear equation at the current value is calculated, and its elements are:

[0139]

[0140] Establish and solve a linear system of equations based on the Jacobian matrix and circuit equations:

[0141]

[0142] Get the correction amount , and go on to calculate the residuals of each equation, and calculate the new residuals:

[0143]

[0144] Solve the linear equations according to the above equations to obtain the current correction value, update the current value until the residual is zero, and obtain the final solution as the current distribution of each layer of conductors in the target line.

[0145] Step S213: Determine the final magnetic field strength of each layer of the target circuit according to the current distribution of each layer of conductors of the target circuit.

[0146] The current in each conductor layer satisfies Kirchhoff's current law, and the magnetic field strength of each layer is an important parameter reflecting the electromagnetic characteristics of the target line. When determining the magnetic field strength of each layer, the current distribution of each conductor layer, the geometric dimensions of the wire, and the electromagnetic characteristics of the material are comprehensively considered. The magnetic field strength of each layer is accurately calculated. The process of calculating the magnetic field strength of each layer is as follows:

[0147]

[0148] Step S14: determining the AC resistance of the target circuit according to the final magnetic field strength of each layer of the target circuit.

[0149] The calculation formula for AC resistance is:

[0150]

[0151] in, is the AC resistance, is the DC resistance, is the temperature coefficient of resistance, is the temperature change, is the correlation coefficient with the longitudinal magnetic field strength.

[0152] In some embodiments, the current distribution and AC resistance of each layer of conductors under different working conditions are interpolated and fitted to obtain a continuous function relationship, including:

[0153] Step S301: Obtain the current distribution and AC resistance of each layer of conductors under different working conditions to construct a discrete data set.

[0154] By changing different working conditions such as temperature and frequency, the current distribution of each layer of conductor under different working conditions is determined, and the corresponding AC resistance is determined by the current distribution of each layer of conductor under different working conditions according to the above steps, so as to calculate the multiple Values ​​and their corresponding operating parameters (current, temperature, frequency ) into a discrete data set.

[0155] Step S302 : Using a cubic spline interpolation algorithm to perform parameter fitting on the discrete data set to obtain a continuous function relationship; wherein the continuous function relationship is used to characterize the mapping relationship between current distribution and AC resistance.

[0156] Among them, the cubic spline interpolation method is used to construct a continuous function relationship. The process of constructing the interpolation function for each variable is as follows:

[0157] For current, temperature, frequency These three variables construct a cubic polynomial interpolation function that is consistent with the value of the discrete data set at each data point and guarantees the continuity of the first and second order derivatives.

[0158] The general form of cubic spline interpolation:

[0159]

[0160] in (k=0, 1, 2, ..., 12) is the unknown coefficient, and i is the number of data points.

[0161] In some embodiments, constructing a heat balance equation for a target circuit and determining the maximum current carrying capacity of the target circuit based on the heat balance equation and a continuous function relationship includes:

[0162] Step S401: Acquire environmental parameters of a target line, and determine Joule heat of solar radiation absorption, Joule heat of conductor radiation dissipation, and Joule heat of conductor convection dissipation of the target line according to the environmental parameters.

[0163] Among them, environmental parameters include real-time ambient temperature, solar radiation intensity and wind speed dynamic parameters.

[0164] The calculation formula for the Joule heat absorbed by solar radiation is as follows:

[0165]

[0166] Where: is the heat absorption coefficient of the conductor surface, which is generally equal to the radiation coefficient, and the typical value is 0.5; is the wire diameter, is the sunlight intensity, W / m 2 .

[0167] The calculation formula for the Joule heat dissipated by wire radiation is as follows:

[0168]

[0169] Where, The emissivity of the conductor surface is 0.23~0.43 for new bright wires and 0.90~0.95 for old wires or wires coated with black preservatives. is the Stefan-Boltzmann constant, , , Indicates the temperature of the conductor itself; Indicates the ambient temperature of the conductor.

[0170] The heat dissipation by convection of the conductor is related to the air flow. It can be expressed by the Reynolds number, a dimensionless number that characterizes the fluid flow. The calculation method is as follows:

[0171]

[0172] Where, Indicates wind speed; Represents the air viscosity coefficient.

[0173] Step S402: Determine the Joule heat of the conductor resistance of the target circuit according to the continuous function relationship using the following formula; wherein the Joule heat of the conductor resistance is:

[0174]

[0175] Where, is the Joule heat of the wire resistance, is a continuous function relationship, is the maximum current carrying capacity;

[0176] Step S403: construct a heat balance equation for the target line based on the Joule heat absorbed by solar radiation, the Joule heat dissipated by conductor radiation, the Joule heat dissipated by conductor convection, and the Joule heat dissipated by conductor resistance, and solve the heat balance equation to obtain the maximum current carrying capacity of the target line.

[0177] The heat balance equation is:

[0178]

[0179] Where, It is understood that by substituting the known Joule heat of solar radiation absorption, Joule heat of wire radiation dissipation, and Joule heat of wire convection dissipation into the heat balance equation, the Joule heat of wire resistance can be determined according to the above heat balance equation, and the maximum current carrying capacity can be calculated through the relationship between the Joule heat of wire resistance and the known continuous function. .

[0180] It is understandable that the embodiment of the present application can accurately calculate the current distribution, AC resistance and maximum current carrying capacity of the target circuit under different operating conditions by constructing an equivalent circuit model and combining nonlinear equation solving, interpolation fitting and thermal balance equation analysis. This method not only improves the accuracy of the calculation, but also provides an important theoretical basis for circuit design and operation. In the specific implementation process, by obtaining the environmental parameters of the target circuit, such as real-time ambient temperature, solar radiation intensity and wind speed, the thermal effect of the circuit can be further analyzed. These environmental parameters have a direct impact on the current carrying capacity of the circuit. Therefore, when designing and evaluating the current carrying capacity of the circuit, the influence of these factors must be fully considered. In addition, this method can also be applied to different types of conductor lines, such as copper conductors, aluminum conductors, etc., and it is only necessary to adjust the equivalent circuit model and nonlinear equations accordingly according to the material properties and geometric dimensions of the specific conductor.

[0181] Based on the same inventive concept, an embodiment of the present application also provides a line current carrying capacity calculation system for implementing the above-mentioned line current carrying capacity calculation method.

[0182] The implementation solution provided by the system to solve the problem is similar to the implementation solution described in the above method. Therefore, the specific limitations in one or more line current carrying capacity calculation system embodiments provided below can refer to the limitations on the line current carrying capacity calculation method above and will not be repeated here.

[0183] like Figure 3 As shown, an embodiment of the present application provides a line current carrying capacity calculation system, including:

[0184] An equivalent model building module 100 is used to build an equivalent circuit model of the target circuit according to the structural parameters of the target circuit;

[0185] The resistance determination module 200 is used to determine the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determine the AC resistance of the target circuit according to the current distribution of each layer of conductors;

[0186] The interpolation fitting module 300 is used to perform interpolation fitting on the current distribution and AC resistance of each layer of conductors under different working conditions to obtain a continuous function relationship;

[0187] The current carrying capacity calculation module 400 is used to construct a heat balance equation for the target circuit and determine the maximum current carrying capacity of the target circuit based on the heat balance equation and the continuous function relationship.

[0188] In some embodiments, the equivalent model building module 100 is used to:

[0189] Obtain the structural parameters of the target line;

[0190] Based on Kirchhoff's voltage law, the equivalent circuit equations of each layer of the target circuit are constructed according to the structural parameters of the target circuit;

[0191] According to the equivalent circuit equations of each layer of the target circuit, the equivalent circuit model of the target circuit is determined.

[0192] In some embodiments, the target line is a single aluminum layer conductor;

[0193] Accordingly, the resistance determination module 200 is configured to:

[0194] Determine the current magnetic field strength of each layer of conductors based on the current current distribution of each layer of conductors in the equivalent circuit model;

[0195] Correcting the current magnetic field strength of each layer of conductors according to the twist pitch parameter to obtain the corrected magnetic field strength of each layer of conductors;

[0196] The equivalent circuit model is updated by using the corrected magnetic field strength of each layer of conductor to obtain an updated equivalent circuit model;

[0197] Determine the updated current distribution of conductors in each layer according to the updated equivalent circuit model;

[0198] Determine whether the current distribution of each layer of conductors after the current update has reached the preset convergence condition;

[0199] If it is determined that the current distribution of the conductors of each layer after the current update does not meet the preset convergence condition, the current current distribution of the conductors of each layer is updated to the current current distribution of the conductors of each layer, and the current current distribution of the conductors of each layer according to the equivalent circuit model is switched to determine the current magnetic field strength of the conductors of each layer, until it is determined that the current current distribution of the conductors of each layer after the current update meets the preset convergence condition, and the final current distribution of the conductors of each layer is output;

[0200] Determine the final magnetic field strength of each layer of the target circuit based on the current distribution of each layer of conductors of the target circuit;

[0201] The AC resistance of the target circuit is determined according to the final magnetic field strength of each layer of the target circuit.

[0202] In some embodiments, the target circuit is a three-layer aluminum conductor;

[0203] Accordingly, the resistance determination module 200 is configured to:

[0204] According to the equivalent circuit model, the nonlinear equations corresponding to each layer of conductors are constructed, and the nonlinear equation group of the target circuit is determined according to the nonlinear equations corresponding to each layer of conductors;

[0205] The Newton iteration method is used to linearize the nonlinear equations and determine the solutions to the nonlinear equations to obtain the current distribution of each layer of conductors in the target line.

[0206] Determine the final magnetic field strength of each layer of the target circuit based on the current distribution of each layer of conductors of the target circuit;

[0207] The AC resistance of the target circuit is determined according to the final magnetic field strength of each layer of the target circuit.

[0208] In some embodiments, the interpolation fitting module 300 is configured to:

[0209] Obtain the current distribution and AC resistance of each layer of conductors under different working conditions and construct a discrete data set;

[0210] The cubic spline interpolation algorithm is used to perform parameter fitting on discrete data sets to obtain a continuous function relationship. The continuous function relationship is used to characterize the mapping relationship between current distribution and AC resistance.

[0211] In some embodiments, the current carrying capacity calculation module 400 is used to:

[0212] Obtaining environmental parameters of the target line, and determining Joule heat absorbed by solar radiation, Joule heat dissipated by conductor radiation, and Joule heat dissipated by conductor convection of the target line based on the environmental parameters;

[0213] The Joule heat of the conductor resistance of the target line is determined by the following formula based on the continuous function relationship; where the Joule heat of the conductor resistance is:

[0214]

[0215] Where, is the Joule heat of the wire resistance, is a continuous function relationship, is the maximum current carrying capacity;

[0216] Based on the Joule heat absorbed by solar radiation, the Joule heat dissipated by conductor radiation, the Joule heat dissipated by conductor convection, and the Joule heat of conductor resistance, a heat balance equation for the target line is constructed and solved to obtain the maximum current carrying capacity of the target line.

[0217] like Figure 4 As shown, an embodiment of the present application provides an electronic device, the electronic device 10 includes a memory 20 and a processor 30, the memory 20 stores a computer program, and when the computer program is executed by the processor 30, the processor 30 executes the steps of the line current carrying capacity calculation method in the above embodiment.

[0218] An embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed, the steps of the line current carrying capacity calculation method in the above embodiment are implemented.

[0219] An embodiment of the present application provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer executes the steps of the line current carrying capacity calculation method described in the above embodiment.

[0220] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, electronic devices, computer storage media, and computer program products can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0221] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatuses.

[0222] It should be understood that, although the various steps in the flowcharts involved in the above embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily performed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0223] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, electronic devices, computer storage media, computer program products 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.

[0224] 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.

[0225] 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.

[0226] 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 executing all or part of the steps of the method described in each embodiment of the present invention via a computer device (which can be a personal computer, server, or network device, etc.). 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.

[0227] 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 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. 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 various embodiments of the present invention.

Claims

1. A method for calculating line current carrying capacity, characterized in that: include: constructing an equivalent circuit model of the target circuit according to structural parameters of the target circuit; Determining the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determining the AC resistance of the target circuit according to the current distribution of each layer of conductors; Performing interpolation fitting on the current distribution of the conductors in each layer and the AC resistance under different working conditions to obtain a continuous function relationship; A heat balance equation for the target circuit is constructed, and a maximum current carrying capacity of the target circuit is determined based on the heat balance equation and the continuous function relationship.

2. The method for calculating line current carrying capacity according to claim 1, characterized in that: The step of constructing an equivalent circuit model of the target circuit according to the structural parameters of the target circuit includes: Acquiring structural parameters of the target circuit; Based on Kirchhoff's voltage law, construct equivalent circuit equations for each layer of the target circuit according to the structural parameters of the target circuit; An equivalent circuit model of the target circuit is determined according to the equivalent circuit equations of each layer of the target circuit.

3. The method for calculating line current carrying capacity according to claim 2, characterized in that: The target circuit is a single-layer aluminum conductor; Accordingly, determining the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determining the AC resistance of the target circuit according to the current distribution of each layer of conductors, includes: Determining the current magnetic field strength of each layer of conductors based on the current current distribution of each layer of conductors in the equivalent circuit model; Correcting the current magnetic field strength of each layer of conductors according to the twist pitch parameter to obtain corrected magnetic field strength of each layer of conductors; Updating the equivalent circuit model using the corrected magnetic field strength of each layer of conductor to obtain an updated equivalent circuit model; Determining the current distribution of conductors in each layer after current update according to the updated equivalent circuit model; Determining whether the current distribution of the conductors in each layer after the current update has reached a preset convergence condition; If it is determined that the currently updated current distribution of the conductors of each layer does not meet the preset convergence condition, updating the currently updated current distribution of the conductors of each layer to the current current distribution of the conductors of each layer, switching to the current current distribution of the conductors of each layer according to the equivalent circuit model, determining the current magnetic field strength of the conductors of each layer, until it is determined that the currently updated current distribution of the conductors of each layer meets the preset convergence condition, and outputting the final current distribution of the conductors of each layer; Determining the final magnetic field strength of each layer of the target circuit according to the current distribution of each layer of conductor of the target circuit; The AC resistance of the target circuit is determined according to the final magnetic field strength of each layer of the target circuit.

4. The method for calculating line current carrying capacity according to claim 2, characterized in that: The target circuit is a three-layer aluminum conductor; Accordingly, determining the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determining the AC resistance of the target circuit according to the current distribution of each layer of conductors, includes: Constructing nonlinear equations corresponding to the conductors of each layer according to the equivalent circuit model, and determining a nonlinear equation group of the target circuit according to the nonlinear equations corresponding to the conductors of each layer; linearizing the nonlinear equations using a Newton iteration method, and determining a solution to the nonlinear equations to obtain a current distribution of each layer of conductors of the target circuit; Determining the final magnetic field strength of each layer of the target circuit according to the current distribution of each layer of conductor of the target circuit; The AC resistance of the target circuit is determined according to the final magnetic field strength of each layer of the target circuit.

5. The method for calculating line current carrying capacity according to claim 1, characterized in that: The interpolation fitting of the current distribution of the conductors in each layer and the AC resistance under different working conditions to obtain a continuous function relationship includes: Obtaining the current distribution of the conductors in each layer and the AC resistance under different working conditions to construct a discrete data set; A cubic spline interpolation algorithm is used to perform parameter fitting on the discrete data set to obtain the continuous function relationship; wherein the continuous function relationship is used to characterize the mapping relationship between the current distribution and the AC resistance.

6. The method for calculating line current carrying capacity according to any one of claims 1 to 5, characterized in that: The step of constructing a heat balance equation for the target circuit and determining the maximum current carrying capacity of the target circuit according to the heat balance equation and the continuous function relationship includes: Acquiring environmental parameters of the target line, and determining Joule heat of solar radiation absorption, Joule heat of conductor radiation dissipation, and Joule heat of conductor convection dissipation of the target line according to the environmental parameters; The Joule heat of the conductor resistance of the target circuit is determined according to the continuous function relationship by the following formula; wherein the Joule heat of the conductor resistance is: Where, is the Joule heat of the wire resistance, is a continuous function relationship, is the maximum current carrying capacity; A heat balance equation for the target circuit is constructed based on the Joule heat absorbed by solar radiation, the Joule heat dissipated by radiation of the conductor, the Joule heat dissipated by convection of the conductor, and the Joule heat of resistance of the conductor. The heat balance equation is solved to obtain the maximum current carrying capacity of the target circuit.

7. A line current carrying capacity calculation system, characterized in that: include: An equivalent model building module, configured to build an equivalent circuit model of the target circuit according to structural parameters of the target circuit; a resistance determination module, configured to determine the current distribution of each layer of conductors of the target circuit according to the equivalent circuit model, and determine the AC resistance of the target circuit according to the current distribution of each layer of conductors; An interpolation fitting module, configured to perform interpolation fitting on the current distribution of the conductors in each layer and the AC resistance under different working conditions to obtain a continuous function relationship; The current carrying capacity calculation module is used to construct a heat balance equation for the target circuit and determine the maximum current carrying capacity of the target circuit according to the heat balance equation and the continuous function relationship.

8. An electronic device, characterized in that: The electronic device includes a memory and a processor, wherein a computer program is stored in the memory. When the computer program is executed by the processor, the processor executes the steps of the line current carrying capacity calculation method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the steps of the line current carrying capacity calculation method according to any one of claims 1 to 6 are implemented.

10. A computer program product, characterized in that The computer program product includes a computer program stored on a non-transitory computer-readable storage medium, wherein the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer is caused to perform the steps of the line current carrying capacity calculation method according to any one of claims 1 to 6.

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