Long cable electromagnetic coupling characteristic calculation simulation method based on transmission line model and related device

Abstract

The invention provides a long cable electromagnetic coupling characteristic calculation simulation method based on a transmission line model and a related device, and is realized based on a pre-constructed transmission line model, and the transmission line model takes a preset load type as a boundary condition. The mathematical model is used for describing an electromagnetic coupling effect of an external excitation source acting on the transmission line-ground coupling system; the method comprises the following steps: defining physical parameters of the transmission line-ground coupling system; defining physical parameters of an external excitation source; defining simulation calculation parameters; selecting a load type; and performing simulation calculation by using the transmission line model to obtain induced voltage data for describing electromagnetic coupling effect characteristics of the transmission line. According to the invention, the preset load type is taken as a boundary condition, the transmission line is utilized to accurately simulate the action process of the wire and the planar electromagnetic wave, the problem of slow calculation speed of the existing field method is solved, the calculation efficiency is effectively improved, and powerful technical support can be provided for electromagnetic protection of a power electronic system.

Description

Technical Field

[0001] The present invention belongs to the technical field of calculating the electromagnetic coupling effect of a strong electromagnetic pulse on a transmission cable, and in particular relates to a method and a related device for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model. Background Art

[0002] Power electronic systems occupy a pivotal position in modern society. They provide the necessary energy and information support for people's work and life, and are the key guarantee for the smooth development of national livelihood facilities. However, with the advancement of science and technology and the increasing complexity of the electromagnetic environment, strong external electromagnetic pulses have become a major threat to power electronic systems. Strong electromagnetic pulses can act on communication and power systems through two mechanisms: front-door coupling and back-door coupling. Front-door coupling directly affects the system receiving device, while back-door coupling mainly targets transmission cables. This coupling effect may cause serious interference or even permanent damage to the system. Therefore, in-depth research on the coupling effect between strong electromagnetic pulses and transmission cables is crucial to improving the protection capability and stability of power electronic systems, and is a difficult problem that needs to be overcome in the current field of power electronic technology.

[0003] When studying the electromagnetic coupling effect of strong electromagnetic pulses on cables, there are two main research ideas: field methods and equivalent path methods. Field methods such as FDTD (finite difference time domain method), TLM (transmission line matrix method), FUTD (finite integral method) and MOM (moment method) have problems such as complex calculation process and large consumption of computing resources, resulting in slow calculation speed and difficulty in meeting the needs of system analysis with high real-time requirements. Although the path method simplifies the coupling effect analysis by constructing an equivalent transmission line equation and using the relationship between cable transfer impedance and transfer admittance, the calculation speed is relatively fast. However, when simulating the plane electromagnetic wave irradiation overhead line, the model construction is not accurate enough and the cable and surrounding environment parameters are not considered carefully enough, resulting in a deviation between the final calculation results and the actual situation, and it is unable to provide sufficiently accurate and comprehensive data support for the protection of power electronic systems, which limits its effective application in complex practical scenarios. Summary of the invention

[0004] In view of this, the present invention provides a calculation and simulation method for the electromagnetic coupling characteristics of long cables based on a transmission line model and related devices, aiming to accurately simulate the interaction process between the wires laid on the ground and the incident plane electromagnetic waves through a method based on the transmission line model, thereby improving the calculation efficiency and practicality, so as to solve the slow calculation speed of the existing field method and the model and parameter problems when the path method simulates and calculates the relevant parameters of the transmission line, and provide effective technical support for the strong electromagnetic pulse protection of the power electronic system.

[0005] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model, which is implemented based on a pre-built transmission line model. The transmission line model is a mathematical model that uses a preset load type as a boundary condition to describe the electromagnetic coupling effect of an external excitation source on a transmission line-earth coupling system;

[0007] The computational simulation method includes the following steps:

[0008] Define the physical parameters of the transmission line-earth coupling system;

[0009] Define the physical parameters of the transmission line-earth coupling system acted by the external excitation source;

[0010] Define simulation calculation parameters;

[0011] Select the load type at both ends of the transmission line in the transmission line-ground coupling system;

[0012] Based on the defined parameters and load types, the transmission line model is used to perform simulation calculations to obtain induced voltage data for describing the electromagnetic coupling effect characteristics of the transmission line.

[0013] Furthermore, the mathematical expression of the transmission line model is as follows:

[0014]

[0015] In the formula, and Represents the position on the transmission line The voltage and current at and They represent the impedance and admittance per unit length of the transmission line respectively; Represents an equivalent voltage source, which is determined by the physical parameters of the transmission line-earth coupling system and the physical parameters of the external excitation source.

[0016] Furthermore, the impedance and admittance per unit length of the transmission line are determined as follows:

[0017]

[0018]

[0019] In the formula, is an imaginary unit, is the angular frequency, and are the inductance and capacitance per unit length of the transmission line, is the impedance per unit length of the earth, and are the dielectric constant and magnetic permeability constant in vacuum, is the propagation constant in the earth, is the transmission line conductor radius, is the height of the transmission line from the ground.

[0020] Furthermore, the propagation constant in the earth is determined as follows:

[0021]

[0022] In the formula, and are the relative permittivity and conductivity of the earth respectively.

[0023] Furthermore, the external excitation source adopts a plane wave, and the equivalent voltage source is determined according to the following formula:

[0024]

[0025] In the formula, is the amplitude of the electric field intensity of the plane wave, Indicated in coordinates The component of the electric field intensity at the location along the length of the transmission line, , and denote the polarization angle, elevation angle and azimuth angle of the incident plane wave, respectively. is an imaginary unit, is the wave constant in vacuum, is the position coordinate of the transmission line, and are the Fresnel reflection coefficients for vertical and horizontal polarizations, respectively.

[0026] Furthermore, the Fresnel reflection coefficient is determined according to the following formula:

[0027]

[0028] In the formula, and are the relative permittivity and conductivity of the earth, is the dielectric constant in vacuum.

[0029] Furthermore, the boundary conditions of the transmission line model are as follows:

[0030]

[0031] In the formula, , and , The transmission line is at the near end and at the far end. The voltage and current at and Load parameters determined for the load types at the near and far ends of the transmission line, respectively, and are the components of the electric field strength at the near end and far end of the transmission line in the length direction of the transmission line respectively; is the height of the transmission line from the ground, and are the equivalent voltage sources at the near and far ends of the transmission line respectively.

[0032] In a second aspect, the present invention provides a device for calculating and simulating electromagnetic coupling characteristics of a long cable based on a transmission line model, which is implemented based on the method for calculating and simulating electromagnetic coupling characteristics of a long cable based on a transmission line model as in the first aspect, and includes:

[0033] The parameter definition module is used to define the physical parameters of the transmission line-earth coupling system; it is also used to define the physical parameters of the external excitation source acting on the transmission line-earth coupling system; it is also used to define the simulation calculation parameters; it is also used to select the load type at both ends of the transmission line in the transmission line-earth coupling system;

[0034] The simulation calculation module is used to perform simulation calculations using a transmission line model based on various defined parameters and load types to obtain induced voltage data for describing the electromagnetic coupling effect characteristics of the transmission line.

[0035] In a third aspect, the present invention provides a computer device, the device comprising a processor and a memory:

[0036] The memory is used to store the computer program and send the instructions of the computer program to the processor;

[0037] The processor executes the method for calculating and simulating electromagnetic coupling characteristics of a long cable based on a transmission line model according to the instructions of the computer program according to the first aspect.

[0038] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model as in the first aspect.

[0039] In summary, the present invention provides a method and related device for calculating and simulating the electromagnetic coupling characteristics of long cables based on a transmission line model, which is implemented based on a pre-built transmission line model. The transmission line model is a mathematical model for describing the electromagnetic coupling effect of an external excitation source acting on a transmission line-earth coupling system with a preset load type as a boundary condition; the method includes defining the physical parameters of the transmission line-earth coupling system; defining the physical parameters of the external excitation source acting on the transmission line-earth coupling system; defining simulation calculation parameters; selecting the load type at both ends of the transmission line in the transmission line-earth coupling system; based on the defined parameters of each type and load type, using the transmission line model for simulation calculation, and obtaining induced voltage data for describing the electromagnetic coupling effect characteristics of the transmission line. The present invention uses the preset load type as a boundary condition, and uses the transmission line to accurately simulate the action process of the conductor and the plane electromagnetic wave, which solves the problem of slow calculation speed of the existing field method, effectively improves the calculation efficiency, and by defining various types of parameters of the model, solves the problems existing in the path method when simulating and calculating the transmission line parameters, which can provide strong technical support for the electromagnetic protection of power electronic systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0041] Figure 1 A flow chart of a method for calculating and simulating electromagnetic coupling characteristics of a long cable based on a transmission line model provided in an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of the structure of a transmission line-earth coupling system of a 10kV overhead transmission line using a plane wave as an external excitation source provided by an embodiment of the present invention;

[0043] Figure 3 A diagram showing a connection method for selecting a load connection method at both ends of a wire (resistance in series with inductance) and a connection method for connecting a capacitor in parallel provided by an embodiment of the present invention;

[0044] Figure 4 Plane wave incident parameters provided by the embodiment of the present invention , the typical waveform of the induced voltage at both ends of the cable when the end of a 10kV overhead transmission line with a height of 6.5m and a length of 1000m is connected to a matching impedance;

[0045] Figure 5 A block diagram of a device for calculating and simulating electromagnetic coupling characteristics of a long cable based on a transmission line model provided in an embodiment of the present invention;

[0046] Figure 6 A block diagram of a computer device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] See also Figure 1 An embodiment of the present invention provides a method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model. The method is implemented based on a pre-constructed transmission line model. The transmission line model is a mathematical model based on a preset load type as a boundary condition to describe the electromagnetic coupling effect of an external excitation source on a transmission line-earth coupling system.

[0049] This embodiment is implemented based on a pre-built transmission line model, which uses a preset load type as a boundary condition, that is, when establishing the transmission line equation, the load conditions at both ends of the transmission line (such as the values ​​and connection methods of resistance, capacitance, and inductance) will be taken into consideration as boundary conditions, making the model closer to the actual application scenario and improving the practicality and accuracy of the model. The purpose of this model is to describe the electromagnetic coupling effect when an external excitation source (such as a plane wave) acts on the transmission line-earth coupling system. It can be achieved by equating the electromagnetic coupling to an equivalent voltage source in the transmission line equation.

[0050] The above calculation simulation method based on the transmission line model includes the following steps:

[0051] Step 1: Define the physical parameters of the transmission line-ground coupling system.

[0052] It should be noted that the transmission line-earth coupling system is an interactive system consisting of a transmission line (such as an overhead cable) and the earth. In this system, there is an electromagnetic coupling relationship between the transmission line and the earth, that is, the electromagnetic field is mutually

[0053] The various parameters of the transmission line-earth coupling system (such as the electrical parameters of the transmission line and the electromagnetic parameters of the earth) play a key role in determining the characteristics of the electromagnetic coupling effect. For example, the inductance and capacitance per unit length of the transmission line will affect the propagation speed and attenuation characteristics of the induced voltage and current on the transmission line; the conductivity of the earth will affect the reflection and refraction of the electromagnetic field in the earth, thereby changing the electromagnetic field distribution around the transmission line, and ultimately affecting the intensity and frequency characteristics of the electromagnetic coupling.

[0054] Therefore, this step first defines its physical parameters for subsequent calculation and analysis.

[0055] Step 2: Define the physical parameters of the transmission line-earth coupling system acted by the external excitation source.

[0056] It should be noted that the external excitation source has a variety of physical parameters, such as electric field intensity amplitude, polarization angle, pitch angle, azimuth angle, etc. These parameters describe the characteristics and propagation direction of the external excitation source. When the external excitation source acts on the transmission line-earth coupling system, different parameter settings will lead to different electromagnetic coupling effects.

[0057] This step defines the physical parameters of these external excitation sources, which helps to accurately simulate the interaction process between the external excitation sources and the transmission line-earth coupling system.

[0058] Step 3: Define simulation calculation parameters.

[0059] It should be noted that the definition of simulation calculation parameters such as simulation time, space step, and calculation accuracy requirements is to control the process and results of simulation calculation. Among them, the simulation time determines the time range covered by the simulation calculation. A longer simulation time can more comprehensively observe the changes of electromagnetic coupling effects over a longer period of time, but it will also increase the amount of calculation. The space step is used to divide the discrete points of the transmission line in space. A smaller space step can more accurately describe the changes in electromagnetic characteristics along the transmission line, but it will also increase the amount of calculation. The calculation accuracy requirements specify the accuracy of the calculation results. Higher accuracy requirements may require more complex calculation algorithms and more computing resources.

[0060] By reasonably setting these simulation calculation parameters, the calculation efficiency can be improved while ensuring the accuracy of the calculation results to meet the needs of different application scenarios.

[0061] Step 4: Select the load type at both ends of the transmission line in the transmission line-ground coupling system.

[0062] It should be noted that the load type at both ends of the transmission line (such as resistance, capacitance, inductance or their combination) will directly affect the voltage and current relationship at both ends of the transmission line, that is, it will participate in the calculation of the transmission line model as a boundary condition. Different load types have different effects on the electromagnetic coupling effect. For example, resistive loads will consume electrical energy according to Ohm's law, so that the current and voltage satisfy a simple linear relationship; capacitive loads will produce a large capacitive reactance for high-frequency signals, affecting the distribution and size of the induced voltage and current at the transmission line terminal; inductive loads will hinder the changing current and also change the voltage and current distribution at both ends of the transmission line. By selecting the appropriate load type, the working state of the transmission line in the actual application scenario can be more accurately simulated, and the electromagnetic coupling effect can be analyzed more accurately.

[0063] Step 5: Based on the defined parameters and load types, a transmission line model is used to perform simulation calculations to obtain induced voltage data for describing the electromagnetic coupling effect characteristics of the transmission line.

[0064] It should be noted that the physical parameters of the transmission line-earth coupling system defined in the previous steps, the physical parameters of the transmission line-earth coupling system acted on by the external excitation source, the simulation calculation parameters, and the load types at both ends of the selected transmission line are all substituted into the transmission line model.

[0065] By solving the transmission line model, the voltage and current distribution along the transmission line and at both ends can be obtained, and the focus is on obtaining the induced voltage data used to describe the electromagnetic coupling effect characteristics of the transmission line. These induced voltage data can reflect important information such as the strength and frequency characteristics of electromagnetic coupling, thereby providing a basis for evaluating electromagnetic interference and designing protective measures.

[0066] Steps 1 to 4 involved in this embodiment do not need to be performed strictly in numerical order during actual operation.

[0067] This embodiment provides a method for calculating and simulating the electromagnetic coupling characteristics of long cables based on a transmission line model. The method based on the transmission line model is adopted. Compared with the field method, the transmission line model focuses on the transmission line itself and the coupling relationship with the earth, which simplifies the calculation of the electromagnetic field. By focusing on the voltage and current changes along the transmission line, the complex calculation of the electromagnetic field in the entire space in the field method is avoided, thereby greatly improving the calculation speed. Compared with the existing method, a more complete and accurate transmission line model is constructed by defining the physical parameters of the transmission line-earth coupling system, the physical parameters of the external excitation source acting on the transmission line-earth coupling system, and the simulation calculation parameters, and using the precise load type as the boundary condition. In this way, when calculating the relevant parameters of the transmission line (such as induced voltage and current), these parameters can be obtained more accurately, which solves the shortcomings of the existing method in terms of models and parameters, and provides reliable data support for the protection design of power electronic systems.

[0068] In one embodiment, a transmission line model is provided, and the mathematical expression of the model is as follows:

[0069]

[0070] In the formula, and Represents the position on the transmission line The voltage and current at and They represent the impedance and admittance per unit length of the transmission line respectively; Represents an equivalent voltage source, which is determined by the physical parameters of the transmission line-earth coupling system and the physical parameters of the external excitation source.

[0071] Based on the transmission line model provided in the foregoing embodiment, in a further embodiment, a method for calculating the impedance and admittance per unit length of a transmission line is provided as follows:

[0072]

[0073]

[0074] In the formula, is an imaginary unit, is the angular frequency, and are the inductance and capacitance per unit length of the transmission line, is the impedance per unit length of the earth, and are the dielectric constant and magnetic permeability constant in vacuum, is the propagation constant in the earth, is the transmission line conductor radius, is the height of the transmission line from the ground.

[0075] Based on the calculation method of the impedance and admittance per unit length of the transmission line provided in the above-mentioned embodiment, in a further embodiment, a calculation method of the propagation constant in the earth is provided as follows:

[0076]

[0077] In the formula, and are the relative permittivity and conductivity of the earth respectively.

[0078] In one embodiment, the external excitation source may be a plane wave, and the equivalent voltage source is determined according to the following formula:

[0079]

[0080] In the formula, is the amplitude of the electric field intensity of the plane wave, Indicated in coordinates The component of the electric field intensity at the location along the length of the transmission line, , and denote the polarization angle, elevation angle and azimuth angle of the incident plane wave, respectively. is an imaginary unit, is the wave constant in vacuum, is the position coordinate of the transmission line, and are the Fresnel reflection coefficients for vertical and horizontal polarizations, respectively.

[0081] like Figure 2 As shown, Figure 2 The structure of a transmission line-earth coupling system of a 10kV overhead transmission line with a plane wave as an external excitation source is shown. The figure uses a three-dimensional rectangular coordinate system, and the incident plane wave is represented by the vector Indicates that it contains horizontal polarization components and the vertical polarization component The cable is located slightly to the right of the center of the figure, with a length of L and a height of h. Its position is represented by the coordinate O and extends along the x-axis. The ground at the bottom of the figure acts as a reflection plane, reflecting the incident wave, and the reflected wave is emitted from the reflection plane on the right side of the cable. The polarization angle of the plane wave is , the pitch angle is , the azimuth is .

[0082] Based on the equivalent voltage source calculation method provided in the foregoing embodiment, in a further embodiment, the Fresnel reflection coefficient is determined according to the following formula:

[0083]

[0084] In the formula, and are the relative permittivity and conductivity of the earth, is the dielectric constant in vacuum.

[0085] In one embodiment, the boundary conditions of the transmission line model are as follows:

[0086]

[0087] In the formula, , and , The transmission line is at the near end and at the far end. The voltage and current at and Load parameters determined for the load types at the near and far ends of the transmission line, respectively, and are the components of the electric field strength at the near end and far end of the transmission line in the length direction of the transmission line respectively; is the height of the transmission line from the ground, and are the equivalent voltage sources at the near and far ends of the transmission line respectively.

[0088] The calculation simulation method proposed in the above embodiment is introduced below with reference to a calculation example.

[0089] 1. Define the main parameters of the cable (including conductor radius, conductor length and height above the ground) and the ground parameters (including ground conductivity and relative dielectric constant).

[0090] In this example, the structure of the 10kV overhead transmission line is as follows: Figure 2 As shown in the figure, the wire radius is set to 0.01m, the wire length is 1000m, the wire height from the ground is 6.5m, the earth conductivity is set to 0.005 S / m, and the relative dielectric constant is set to 10.

[0091] 2. Define the plane wave parameters, including the plane wave incident angles such as polarization angle, elevation angle and azimuth angle.

[0092] The polarization angle of a plane wave is , the pitch angle is , the azimuth is , so the plane wave incident angle is defined as .

[0093] 3. Define simulation calculation parameters.

[0094] The simulation duration is defined as 6 μs, the spatial step is defined as 0.5 m, and the error control parameter is defined as 1E-4.

[0095] 4. Select the load type.

[0096] The load connection method at both ends of the wire is "(resistance in series with inductance) parallel with capacitance". The connection method is as follows Figure 3 As shown, the capacitor LL = 0H, CL = 0F, and RL is the matching load of the 10kV overhead transmission line, which is 430Ω.

[0097] 5. Based on the calculation expression provided in the above embodiment, simulation calculation is performed to obtain the induced voltage waveform at both ends of the overhead line, such as Figure 4 As shown, these waveforms reflect the time-varying state of the induced voltage generated at both ends of the overhead line when the overhead line is subjected to external electromagnetic excitation.

[0098] Based on the same inventive concept, the embodiment of the present application also provides a long cable electromagnetic coupling characteristic calculation simulation device based on a transmission line model for implementing the above-mentioned long cable electromagnetic coupling characteristic calculation simulation method based on a transmission line model. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in the embodiment of the long cable electromagnetic coupling characteristic calculation simulation device based on a transmission line model provided below can refer to the limitations of the long cable electromagnetic coupling characteristic calculation simulation method based on a transmission line model above, and will not be repeated here.

[0099] See also Figure 5 The embodiment of the present invention further provides a device for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model, which is implemented based on the method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model as in the first aspect, and includes:

[0100] The parameter definition module is used to define the physical parameters of the transmission line-earth coupling system; it is also used to define the physical parameters of the external excitation source acting on the transmission line-earth coupling system; it is also used to define the simulation calculation parameters; it is also used to select the load type at both ends of the transmission line in the transmission line-earth coupling system;

[0101] The simulation calculation module is used to perform simulation calculations using a transmission line model based on various defined parameters and load types to obtain induced voltage data for describing the electromagnetic coupling effect characteristics of the transmission line.

[0102] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0103] Reference Figure 6 An embodiment of the present invention further provides a computer device, comprising: a memory and a processor and a computer program stored in the memory. When the computer program is executed on the processor, a method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model as described in any one of the above methods is implemented.

[0104] The computer device may be a desktop computer, a notebook, a PDA, a cloud server or other computing device. The computer device may include, but is not limited to, a processor and a memory. Those skilled in the art will understand that Figure 6 It is only an example of a computer device and does not constitute a limitation of the computer device. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, it may also include input and output devices, network access devices, etc.

[0105] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0106] In some embodiments, the memory may be an internal storage unit of the computer device, such as a hard disk or memory of the computer device. In other embodiments, the memory may also be an external storage device of the computer device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the computer device. Further, the memory may include both an internal storage unit and an external storage device of the computer device. The memory is used to store an operating system, an application program, a boot loader (BootLoader), data, and other programs, such as the program code of the computer program. The memory may also be used to temporarily store data that has been output or is to be output.

[0107] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model as described in any one of the above methods is implemented.

[0108] In this embodiment, if the integrated unit is implemented in the form of 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 present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium can at least include: any entity or device that can carry the computer program code to the camera / terminal device, recording medium, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. For example, USB flash drive, mobile hard disk, disk or optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0109] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0110] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0111] In the embodiments disclosed in the present application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, 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 through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0112] 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 the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model, characterized in that: The transmission line model is implemented based on a pre-built transmission line model, wherein the transmission line model is a mathematical model for describing the electromagnetic coupling effect of an external excitation source on a transmission line-earth coupling system with a preset load type as a boundary condition; The computational simulation method comprises the following steps: defining physical parameters of the transmission line-earth coupling system; defining physical parameters of the transmission line-earth coupling system acted upon by the external excitation source; Define simulation calculation parameters; Selecting the load types at both ends of the transmission line in the transmission line-earth coupling system; Based on the defined parameters of various types and the load type, the transmission line model is used to perform simulation calculations to obtain induced voltage data for describing the electromagnetic coupling effect characteristics of the transmission line.

2. The method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model according to claim 1, characterized in that: The mathematical expression of the transmission line model is as follows: In the formula, and Represents the position on the transmission line The voltage and current at and They represent the impedance and admittance per unit length of the transmission line respectively; represents an equivalent voltage source, and the equivalent voltage source is determined by the physical parameters of the transmission line-earth coupling system and the physical parameters of the external excitation source.

3. The method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model according to claim 2, characterized in that: The impedance and admittance per unit length of the transmission line are determined as follows: In the formula, is an imaginary unit, is the angular frequency, and are the inductance and capacitance per unit length of the transmission line, is the impedance per unit length of the earth, and are the dielectric constant and magnetic permeability constant in vacuum, is the propagation constant in the earth, is the transmission line conductor radius, is the height of the transmission line from the ground.

4. The method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model according to claim 3, characterized in that: The propagation constant in the earth is determined as follows: In the formula, and are the relative permittivity and conductivity of the earth respectively.

5. The method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model according to claim 2, characterized in that: The external excitation source adopts a plane wave, and the equivalent voltage source is determined according to the following formula: In the formula, is the amplitude of the electric field intensity of the plane wave, Indicated in coordinates The component of the electric field intensity at the location along the length of the transmission line, , and denote the polarization angle, elevation angle and azimuth angle of the incident plane wave, respectively. is an imaginary unit, is the wave constant in vacuum, is the position coordinate of the transmission line, and are the Fresnel reflection coefficients for vertical and horizontal polarizations, respectively.

6. The method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model according to claim 5, characterized in that: The Fresnel reflection coefficient is determined according to the following formula: In the formula, and are the relative permittivity and conductivity of the earth, is the dielectric constant in vacuum.

7. The method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model according to claim 2, characterized in that: The boundary conditions of the transmission line model are as follows: In the formula, , and , The transmission line is at the near end and at the far end. The voltage and current at and Load parameters determined for the load types at the near and far ends of the transmission line, respectively, and are the components of the electric field strength at the near end and far end of the transmission line in the length direction of the transmission line respectively; is the height of the transmission line from the ground, and are the equivalent voltage sources at the near and far ends of the transmission line respectively.

8. A device for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model, characterized in that: The method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model as claimed in any one of claims 1 to 7 comprises: A parameter definition module, used to define the physical parameters of the transmission line-earth coupling system; also used to define the physical parameters of the external excitation source acting on the transmission line-earth coupling system; also used to define simulation calculation parameters; and also used to select the load type at both ends of the transmission line in the transmission line-earth coupling system; The simulation calculation module is used to perform simulation calculation using the transmission line model based on the defined parameters of various types and the load type, so as to obtain induced voltage data for describing the electromagnetic coupling effect characteristics of the transmission line.

9. A computer device, characterized in that: The device comprises a processor and a memory: The memory is used to store a computer program and send instructions of the computer program to the processor; The processor executes a method for calculating and simulating electromagnetic coupling characteristics of a long cable based on a transmission line model according to any one of claims 1 to 7 according to the instructions of the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, a method for calculating and simulating the electromagnetic coupling characteristics of a long cable based on a transmission line model as described in any one of claims 1 to 7 is implemented.

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