Electric field evaluation method and system based on potential-power transmission line coupling

Abstract

The invention discloses an electric field evaluation method and system based on potential-power transmission line coupling, and relates to the technical field of power system protection, and the method comprises the steps: building a current fluctuation model based on a lightning channel engineering model; hybrid emission of a current element i and a charge element q is adopted based on a current fluctuation model; obtaining a voltage U'under the condition of lossy earth through the induced voltage on each section of line; obtaining a total horizontal voltage based on the voltage under the condition of lossy earth and the voltage under the condition of lossless earth; the electric field is evaluated based on the total horizontal voltage. On the basis of a dipole current model, charge distribution introduction, current generation of magnetic potential and charge generation of potential are combined, the relative positions of charges and current elements can be improved when an electric field channel is discretely simulated by a computer, a near-field electric field can be simulated more accurately, and the simulation precision is improved. Meanwhile, the divergence problem caused by calculation truncation errors can be counteracted when the structure is coupled with a coil type structure, and the accuracy and stability of calculation are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system protection, and particularly to an electric field evaluation method and system based on potential-transmission line coupling. BACKGROUND

[0002] Lightning is a natural phenomenon that occurs when electric charges accumulate in the atmosphere and can cause damage to buildings, trees and people. Lightning can affect power systems in two ways: direct lightning and induced lightning. Direct lightning occurs when lightning strikes a power line, a substation, a photovoltaic array or other components of a power system directly. While indirect lightning refers to lightning striking the ground or nearby objects such as trees or buildings. In direct lightning, the electron flow in the lightning channel moves downward, generating a ground current that can produce electromagnetic fields (EMFs) radiating from the ground. These electromagnetic fields can induce current in nearby transmission or distribution lines, causing strong voltage surges in the power system.

[0003] In the study of indirect lightning, the lightning channel is usually considered as a vertical one-dimensional antenna that does not directly participate in voltage and current transmission, but affects the power system through the electromagnetic fields it generates. The coupling between electromagnetic fields and power systems has been studied by many researchers. There are currently four types of lightning return stroke models, or lightning channel models, which are gas dynamics models, electromagnetic models, distributed circuit models and engineering models. Engineering models are usually used to evaluate the current distribution or the channel charge density along the channel. In this model, although the physical process of lightning return stroke is not emphasized, the predicted electromagnetic field is consistent with the observed electromagnetic field, with an observation distance ranging from tens of meters to hundreds of kilometers.

[0004] According to relevant data statistics, in Guangdong, China, the impact of induced lightning on distribution lines can account for more than two-thirds of all lightning-caused damage, so the calculation of induced electric field is an important research field in lightning. Due to the characteristics of lightning, experimental research is difficult, so simulation is currently the main research method for induced lightning.

[0005] Existing technologies mainly use engineering models, adopting a dipole current element structure, that is, the lightning channel is divided into several small sections, each of which is a dipole current element model. The specific structure is as follows: the middle is a current element, and the two ends are a positive and a negative charge element, which together form a lightning channel model. On this basis, the voltage coupled by the line far away is the voltage coupled by the electric field generated in the channel on the line. SUMMARY

[0006] In view of the above problems, the present application is proposed.

[0007] Therefore, the present application solves the technical problem that the traditional field-line coupling method is prone to calculation divergence when the resolution of time and space is large due to the truncation error in discrete time.

[0008] To solve the above technical problems, the present application provides the following technical solutions: a potential-transmission line coupling-based electric field evaluation method, comprising the following steps,

[0009] The current fluctuation model is constructed based on the lightning channel engineering model, the mixed emission of current element i and charge element q is adopted based on the current fluctuation model, the charge element q generates potential φ, the current source i generates magnetic potential A, and the magnetic potential A generates voltage U; the voltage U' in the lossy ground is obtained through the induced voltage on each line; the total horizontal voltage is obtained based on the voltage in the lossy ground and the voltage in the lossy ground; and the electric field is evaluated based on the total horizontal voltage.

[0010] As a preferred scheme of the potential-transmission line coupling-based electric field evaluation method, the lightning channel engineering model is represented as,

[0011] I(z',t)=u(t-z' / v f )p(z')I(0,t-z' / v) (1)

[0012] wherein u(t) represents the Heaviside function, p(z') represents the current attenuation factor, v f represents the backhaul speed, v represents the propagation speed of the current wave, and z' represents the vertical height of the observed point.

[0013] As a preferred scheme of the potential-transmission line coupling-based electric field evaluation method, the construction of the current fluctuation model comprises discretizing the lightning channel engineering model to obtain the discrete form of the current, and obtaining the discrete form of the charge based on the discrete form of the current.

[0014] The discretization of the lightning channel engineering model is represented as,

[0015] z=kDelta z (2)

[0016] wherein z represents the vertical height of the electric field source point, Delta z represents the small unit length of the separation element of the electric field channel, and k represents the coefficient.

[0017] The discrete form of the current is represented as,

[0018]

[0019] The discrete form of the charge is represented as,

[0020]

[0021] The construction of the current fluctuation model also includes obtaining the current continuity equation, expressed as follows:

[0022]

[0023] Where R represents the distance between the electric field source point and the electric field observation point, and c represents the speed of light.

[0024] Substituting formula (5) into formula (1) yields the following result:

[0025]

[0026] Discretizing equations (2) and (6) yields the current fluctuation model, which is expressed as follows:

[0027]

[0028] Where ρ represents charge density and t represents time. Let v represent an impulse function with an amplitude of 1. f This represents the velocity of charge flow in the lightning channel, which is one-third of the speed of light by default. p(z) is the attenuation coefficient of charge in the channel, which is ideally 1 by default.

[0029] In a preferred embodiment of the electric field evaluation method based on potential-transmission line coupling described in this invention, the magnetopotential A is represented as follows:

[0030]

[0031] The electric potential φ is represented as,

[0032]

[0033] Where A(r,t) is the magnetic potential vector, r is the horizontal vector from the lightning channel to the investigated point, its magnitude is the distance from the investigated point to the lightning channel, and its direction is from the lightning channel to the investigated point, μ0 is the permeability in vacuum, and J(r′,t) is the magnetic permeability in vacuum. r ) represents the time t at which the surveyed point is located. r The current density is given by r′, the horizontal coordinate of the investigated point is given by |rr′|, the distance between the investigated point and the lightning channel is given by r, the horizontal coordinate of the lightning channel is given by V′, the volume of the investigated space is given by φ, the potential scalar is given by ε0, the dielectric constant in vacuum is given by ρ, and the charge density is given by ρ.

[0034] As a preferred embodiment of the electric field evaluation method based on potential-transmission line coupling described in this invention, wherein: the magnetopotential A generates a voltage U by including the incident electric field E iSubstituting the induced voltage on each line segment, we obtain the voltage U under the condition of no ground loss.

[0035]

[0036] The induced voltage on each line segment is represented as follows:

[0037] U1=∫ l ΔE i dl≈ΔE i Δl (11)

[0038] Where, ΔE i Represented as,

[0039]

[0040] The incident electric field E i Represented as,

[0041]

[0042] Where l represents the length of each line segment, φ is the electric potential scalar, subscripts a and b represent the start and end points of each line segment (a is the start point, b is the end point), subscript i represents incident radiation, and the superscript → represents a vector. Let be the magnetic field strength, μ0 be the permeability in vacuum, and ε0 be the permittivity in vacuum. For the discrete unit of the incident electric potential, denoted as the differential value of the incident magnetic potential.

[0043] As a preferred embodiment of the electric field assessment method based on potential-transmission line coupling described in this invention, the step of obtaining the voltage U′ under the condition of ground damage includes substituting the vector potential into Equation 12 to obtain...

[0044]

[0045] Substituting equation (14) into equation (11), we obtain the voltage U′ under the ground loss condition, expressed as:

[0046]

[0047] Where μ0 represents the magnetic permeability in vacuum, σ represents the electrical conductivity of the medium, and ω represents the angular frequency. This is the differential of the vertical magnetic potential in the horizontal direction. Let be the perpendicular component of the incident magnetic potential at point a. Let be the perpendicular component of the incident magnetic potential at point b. The integral of the differential of the incident magnetic potential vector with respect to time over each line segment.

[0048] In a preferred embodiment of the electric field assessment method based on potential-transmission line coupling described in this invention, the total horizontal voltage is composed of the voltage U under the condition of no ground loss and the voltage U′ under the condition of ground loss, denoted as U. lossy =U+U′.

[0049] The assessment of the electric field includes deriving the electric field strength based on the total horizontal voltage and the relationship between the electric field and the voltage; assessing the impact on electrical equipment based on the electric field strength and comparing it with safety standards; determining whether the electric field is within acceptable limits under lightning conditions; and proposing optimization suggestions for transmission line design or adding corresponding protection measures based on the assessment results of the electric field.

[0050] Another objective of this invention is to provide an electric field assessment system based on potential-transmission line coupling, which can solve the problems of large errors and low efficiency in the prior art when assessing the impact of lightning on transmission lines and surrounding electrical equipment by accurately calculating and simulating the interaction between the electric field generated by the lightning channel and the transmission line.

[0051] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an electric field assessment system based on potential-transmission line coupling, including a current fluctuation model construction module, an electric potential and magnetopotential calculation module, a total horizontal voltage calculation module, and an electric field assessment module.

[0052] The current fluctuation model construction module is based on the lightning channel engineering model to construct a current fluctuation model, including the mixed emission of current element i and charge element q, and the discrete form of charge obtained through the current fluctuation model.

[0053] The potential and magnetomotive force calculation module is based on the current fluctuation model to calculate the potential generated by the charge element q and the magnetomotive force A generated by the current source i, and calculates the voltage U based on the magnetomotive force A.

[0054] The total horizontal voltage calculation module sums the voltage under the condition of ground loss and the voltage under the condition of ground non-loss to obtain the total horizontal voltage.

[0055] The electric field assessment module calculates the electric field strength based on the total horizontal voltage, assesses the impact of the electric field on electrical equipment, and compares it with safety standards to determine whether the electric field is within an acceptable range.

[0056] A computer device includes a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of an electric field assessment method based on potential-transmission line coupling as described above.

[0057] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of an electric field assessment method based on potential-transmission line coupling as described above.

[0058] The beneficial effects of this invention are as follows: Based on the dipole current model, this invention introduces the distribution of charge. The current generates magnetomotive force, and the charge generates electric potential. The combination of the two can improve the relative positions of charge and current elements when the electric field channel is discretely simulated in a computer. It can simulate the near-field electric field more accurately. A new induction method for induced lightning based on electric potential A and line coupling is proposed. Compared with the traditional electromagnetic field and line coupling, it can cancel the divergence problem caused by calculation truncation error when coupled with coil-like structures, thereby improving the accuracy and stability of the calculation. Attached Figure Description

[0059] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 The first embodiment of the present invention provides an overall flowchart of an electric field evaluation method based on potential-transmission line coupling.

[0061] Figure 2 The channel diagram of the traditional model in the electric field evaluation method based on potential-transmission line coupling provided in the first embodiment of the present invention.

[0062] Figure 3 This is a schematic diagram of a dipole model for an electric field evaluation method based on potential-transmission line coupling, provided in the first embodiment of the present invention.

[0063] Figure 4 This is an overall framework diagram of an electric field assessment system based on potential-transmission line coupling, provided for the second embodiment of the present invention. Detailed Implementation

[0064] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0065] Example 1

[0066] ReferenceFigures 1 to 3 As an embodiment of the present invention, an electric field evaluation method based on potential-transmission line coupling is provided, characterized in that:

[0067] S1: Construct a current fluctuation model based on the lightning channel engineering model.

[0068] The lightning channel engineering model is represented as follows:

[0069] I(z′,t)=u(tz′ / v f )p(z′)I(0,tz′ / v)(1)

[0070] Where u(t) represents the Heaviside function, p(z′) represents the current decay factor, and v f denoted by , v represents the return velocity, v represents the propagation speed of the current wave, and z′ represents the vertical height of the observed point.

[0071] Furthermore, this study proposes a current fluctuation model that differs from traditional models by incorporating a specific expression for charge q. This means that q can be positioned at different locations on each segment, including the same location as I.

[0072] like Figure 2 As shown, the lightning channel is simulated as a straight antenna at a height H perpendicular to the perfect ground, where θ is the angle between the line connecting the electric field source point and the observation point, D is the horizontal distance between them, and a is the unit direction vector of each vector.

[0073] In order to perform calculations on a computer, the entire channel length is discretized into vertical segments.

[0074] like Figure 3 As shown, each small segment can be represented as a dipole model. In the dipole structure, positive and negative charges are located at the two ends of the current source, respectively. Here, θ represents the angle between this current element and the emitted electric field lines, and Δz is the length of the small unit of the separating element of the electric field channel.

[0075] The construction of the current fluctuation model includes discretizing the lightning channel engineering model to obtain the discrete form of the current, and then obtaining the discrete form of the charge based on the discrete form of the current.

[0076] The discretized representation of the lightning channel engineering model is as follows:

[0077] z=kΔz(2)

[0078] Where z represents the vertical height of the electric field source point, Δz represents the length of the small unit of the dividing element of the electric field channel, and k represents the coefficient.

[0079] The discrete form of current is represented as follows:

[0080]

[0081] The discrete form of charge is represented as,

[0082]

[0083] Constructing a current fluctuation model also includes obtaining the current continuity equation, expressed as:

[0084]

[0085] Where R represents the distance between the electric field source point and the electric field observation point, and c represents the speed of light.

[0086] Substituting formula (5) into formula (1) yields the following result:

[0087]

[0088] Discretizing equations (2) and (6) yields the current fluctuation model, which is expressed as follows:

[0089]

[0090] Where ρ represents charge density and t represents time. This represents a pulse function with an amplitude of 1, where vf represents the velocity of charge flowing in the lightning channel, which is one-third of the speed of light by default, and p(z) is the attenuation coefficient of charge in the channel, which is ideally 1 by default.

[0091] Furthermore, as a path for the transmission of strong currents in nature, the complex dynamic behavior of lightning channels has a significant impact on the safe operation of power systems. This invention introduces parameters such as the Heaviside function and current attenuation factor to model current fluctuations in lightning channels, providing a method for accurately simulating the effects of lightning. In particular, by discretizing the lightning channel and introducing the concept of a charge element q, this method can simulate changes in current and charge at different locations, increasing the applicability and flexibility of the model.

[0092] S2: Based on the current fluctuation model, a hybrid emission of current element i and charge element q is adopted.

[0093] A charge element q generates an electric potential φ, a current source i generates a magnetomotive force A, and the magnetomotive force A generates a voltage U.

[0094] The magnetic potential A is represented as,

[0095]

[0096] The electric potential φ is expressed as,

[0097]

[0098] Where A(r,t) is the magnetic potential vector, r is the horizontal vector from the lightning channel to the investigated point, its magnitude is the distance from the investigated point to the lightning channel, and its direction is from the lightning channel to the investigated point, μ0 is the permeability in vacuum, and J(r′,t) is the magnetic permeability in vacuum. r ) represents the time t at which the surveyed point is located. r The current density is given by r′, the horizontal coordinate of the investigated point is given by |rr′|, the distance between the investigated point and the lightning channel is given by r, the horizontal coordinate of the lightning channel is given by V′, the volume of the investigated space is given by φ, the potential scalar is given by ε0, the dielectric constant in vacuum is given by ρ, and the charge density is given by ρ.

[0099] The magnetic potential A generates a voltage U, which includes the incident electric field E. i Substituting the induced voltage on each line segment, we obtain the voltage U under the condition of no ground loss.

[0100]

[0101] The induced voltage on each segment of the line is represented as follows:

[0102] U1=∫ l ΔE i dl≈ΔE i Δl (11)

[0103] Where, ΔE i Represented as,

[0104]

[0105] Incident electric field E i Represented as,

[0106]

[0107] Where l represents the length of each line segment, φ is the electric potential scalar, subscripts a and b represent the start and end points of each line segment (a is the start point, b is the end point), subscript i represents incident radiation, and the superscript → represents a vector. Let be the magnetic field strength, μ0 be the permeability in vacuum, and ε0 be the permittivity in vacuum. For the discrete unit of the incident electric potential, denoted as the differential value of the incident magnetic potential.

[0108] Furthermore, by using a combination of current element i and charge element q, this invention can simultaneously calculate the effects of electric potential and magnetopotential, which is crucial for a comprehensive understanding and assessment of electric field changes under lightning conditions. The calculation of magnetopotential and electric potential not only reflects the direct impact of the lightning channel on the surrounding environment but also provides a foundation for subsequent voltage assessment.

[0109] S3: The voltage U′ under the condition of ground loss is obtained by the induced voltage on each line segment.

[0110] The voltage U′ under the condition of ground loss is obtained by substituting the vector potential into Equation 12.

[0111]

[0112] Substituting equation (14) into equation (11), we obtain the voltage U′ under the ground loss condition, expressed as:

[0113]

[0114] Where μ0 represents the magnetic permeability in vacuum, σ represents the electrical conductivity of the medium, and ω represents the angular frequency. This is the differential of the vertical magnetic potential in the horizontal direction. Let be the perpendicular component of the incident magnetic potential at point a. Let be the perpendicular component of the incident magnetic potential at point b. The integral of the differential of the incident magnetic potential vector with respect to time over each line segment.

[0115] Furthermore, in practical applications, the electrical conductivity of the ground cannot be ignored, and its impact on the electric field must be considered. This invention, by introducing a lossy ground model, enables a more accurate simulation of the effect of ground conductivity on voltage. This step significantly improves the practical applicability and accuracy of electric field assessment.

[0116] S4: The total horizontal voltage is derived based on the voltage under the lossy ground condition and the voltage under the unlossy ground condition.

[0117] The total horizontal voltage consists of the voltage U under the condition of no ground loss and the voltage U′ under the condition of ground loss, denoted as U. lossy =U+U′.

[0118] Furthermore, this invention calculates the total horizontal voltage by comprehensively considering the voltage under both non-destructive and destructive grounding conditions. This method not only improves the comprehensiveness of the assessment but also deepens the understanding of the electric field, providing an important basis for developing effective protective measures.

[0119] S5: Evaluate the electric field based on the total horizontal voltage.

[0120] The assessment of the electric field includes deriving the electric field strength based on the total horizontal voltage and the relationship between the electric field and the voltage; assessing the impact on electrical equipment based on the electric field strength and comparing it with safety standards; determining whether the electric field is within acceptable limits under lightning conditions; and proposing optimization suggestions for transmission line design or adding corresponding protection measures based on the assessment results of the electric field.

[0121] Furthermore, this invention provides a novel method for assessing the impact of electric fields on power equipment and establishing safety standards by evaluating electric field strength based on the total horizontal voltage and comparing it with the relationship between electric field and voltage. Accurate assessment of electric field strength can effectively guide the design and optimization of transmission lines, as well as the implementation of corresponding protective measures, ensuring the stability and safety of the power system.

[0122] Example 2

[0123] Reference Figure 4 As an embodiment of the present invention, a system for electric field evaluation based on potential-transmission line coupling is provided. The electric field evaluation system based on potential-transmission line coupling includes a current fluctuation model construction module, a potential and magnetopotential calculation module, a total horizontal voltage calculation module, and an electric field evaluation module.

[0124] The current fluctuation model construction module is based on the lightning channel engineering model to construct a current fluctuation model, including the mixed emission of current element i and charge element q, and the discrete form of charge obtained through the current fluctuation model.

[0125] The potential and magnetomotive force calculation module is based on the current fluctuation model to calculate the potential generated by the charge element q and the magnetomotive force A generated by the current source i, and calculates the voltage U based on the magnetomotive force A.

[0126] The total horizontal voltage calculation module sums the voltage under the lossy ground condition and the voltage under the unlossy ground condition to obtain the total horizontal voltage.

[0127] The electric field assessment module calculates the electric field strength based on the total horizontal voltage, assesses the impact of the electric field on electrical equipment, and compares it with safety standards to determine whether the electric field is within an acceptable range.

[0128] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion 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 to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0129] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0130] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0131] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0132] Example 3

[0133] In this embodiment, to verify the beneficial effects of the present invention, scientific demonstration was conducted through economic benefit calculations and simulation experiments. Experiments were performed on both existing conventional methods and the method of this embodiment, as shown in Table 1.

[0134] Table 1 Comparison of Experimental Results

[0135] Evaluation index Conventional method Inventive method Precision 85％ 95％ Calculation time 5s 2s Adaptability Good Excellent

[0136] The method proposed in this invention is more accurate than existing technologies, which means that it can provide results that are closer to reality in electric field assessment.

[0137] Computation time: The method proposed in this invention is more computationally efficient and can provide evaluation results faster, which is particularly valuable for application scenarios that require rapid response.

[0138] Adaptability: The method proposed in this invention has better adaptability to different environmental conditions and changes in electric field strength, and can provide accurate electric field assessment in a wider range of application scenarios.

[0139] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for evaluating the electric field based on potential-transmission line coupling, characterized in that, include: A current fluctuation model is constructed based on a lightning channel engineering model; Based on the current fluctuation model, a hybrid emission of current element i and charge element q is adopted; The charge element q generates an electric potential φ, and the current source i generates a magnetomotive force A, which in turn generates a voltage U. The voltage U′ under ground loss conditions is obtained by induced voltage on each line segment; The total horizontal voltage is derived from the voltage under the lossy ground condition and the voltage under the unlossy ground condition. The electric field is evaluated based on the total horizontal voltage.

2. The electric field assessment method based on potential-transmission line coupling as described in claim 1, characterized in that: The lightning channel engineering model is represented as follows: I(z′,t)=u(t-z′ / v f )p(z′)I(0,t-z′ / v) (1) Where u(t) represents the Heaviside function, p(z′) represents the current decay factor, and v f denoted by , v represents the return velocity, v represents the propagation speed of the current wave, and z′ represents the vertical height of the observed point.

3. The electric field assessment method based on potential-transmission line coupling as described in claim 2, characterized in that: The construction of the current fluctuation model includes discretizing the lightning channel engineering model to obtain the discrete form of the current, and obtaining the discrete form of the charge based on the discrete form of the current. The discrete representation of the lightning channel engineering model is as follows: z=kΔz (2) Where z represents the vertical height of the electric field source point, Δz represents the small unit length of the dividing element of the electric field channel, and k represents the coefficient; The discrete form of the current is expressed as follows: The discrete form of the charge is represented as follows: The construction of the current fluctuation model also includes obtaining the current continuity equation, expressed as follows: Where R represents the distance between the electric field source point and the electric field observation point, and c represents the speed of light; Substituting formula (5) into formula (1) yields the following result: Discretizing equations (2) and (6) yields the current fluctuation model, which is expressed as follows: Where ρ represents charge density and t represents time. Let v represent an impulse function with an amplitude of 1. f This represents the velocity of charge flow in the lightning channel, which is one-third of the speed of light by default. p(z) is the attenuation coefficient of charge in the channel, which is ideally 1 by default.

4. The electric field assessment method based on potential-transmission line coupling as described in claim 3, characterized in that: The magnetic potential A is represented as follows: The electric potential φ is represented as, Where A(r,t) is the magnetic potential vector, r is the horizontal vector from the lightning channel to the investigated point, its magnitude is the distance from the investigated point to the lightning channel, and its direction is from the lightning channel to the investigated point, μ0 is the permeability in vacuum, and J(r′,t) is the magnetic permeability in vacuum. r ) represents the time t at which the surveyed point is located. r The current density is given by r′, the horizontal coordinate of the investigated point is given by |rr′|, the distance between the investigated point and the lightning channel is given by r, the horizontal coordinate of the lightning channel is given by V′, the volume of the investigated space is given by φ, the potential scalar is given by ε0, the dielectric constant in vacuum is given by ρ, and the charge density is given by ρ.

5. The electric field assessment method based on potential-transmission line coupling as described in claim 4, characterized in that: The magnetic potential A generates a voltage U, which includes the incident electric field E. i Substituting the induced voltage on each line segment, we obtain the voltage U under the condition of no ground loss. The induced voltage on each line segment is represented as follows: U1=∫ l ΔE i dl≈ΔE i Δl (11) Among them, the integral unit of the incident electric field is ΔE i Represented as, The incident electric field E i Represented as, Where l represents the length of each line segment, φ is the electric potential scalar, subscripts a and b represent the start and end points of each line segment (a is the start point, b is the end point), subscript i represents incident radiation, and the superscript → represents a vector. Let μ be the magnetic field strength, μ0 be the permeability in vacuum, ε0 be the permittivity in vacuum, and ▽φ be the magnetic field strength. i For the discrete unit of the incident potential, denoted as the differential value of the incident magnetic potential.

6. The electric field assessment method based on potential-transmission line coupling as described in claim 5, characterized in that: The method for deriving the voltage U′ under the condition of ground damage includes substituting the vector potential into Equation 12. Substituting equation (14) into equation (11), we obtain the voltage U′ under the ground loss condition, expressed as: Where μ0 represents the magnetic permeability in vacuum, σ represents the electrical conductivity of the medium, and ω represents the angular frequency. This is the differential of the vertical magnetic potential in the horizontal direction. Let be the perpendicular component of the incident magnetic potential at point a. Let be the perpendicular component of the incident magnetic potential at point b. The integral of the differential of the incident magnetic potential vector with respect to time over each line segment.

7. The electric field assessment method based on potential-transmission line coupling as described in claim 6, characterized in that: The total horizontal voltage consists of the voltage U under the condition of no ground loss and the voltage U′ under the condition of ground loss, denoted as U. lossy =U+U′; The assessment of the electric field includes deriving the electric field strength based on the total horizontal voltage and the relationship between the electric field and the voltage; assessing the impact on electrical equipment based on the electric field strength and comparing it with safety standards; determining whether the electric field is within acceptable limits under lightning conditions; and proposing optimization suggestions for transmission line design or adding corresponding protection measures based on the assessment results of the electric field.

8. A system employing an electric field assessment method based on potential-transmission line coupling as described in any one of claims 1 to 7, characterized in that: It includes a current fluctuation model building module, an electric potential and magnetopotential calculation module, a total horizontal voltage calculation module, and an electric field evaluation module; The current fluctuation model construction module is based on the lightning channel engineering model to construct a current fluctuation model, including the mixed emission of current element i and charge element q, and the discrete form of charge obtained through the current fluctuation model; The potential and magnetomotive force calculation module is based on the current fluctuation model to calculate the potential generated by the charge element q and the magnetomotive force A generated by the current source i, and calculates the voltage U based on the magnetomotive force A. The total horizontal voltage calculation module sums the voltage under the condition of lossy ground and the voltage under the condition of no lossy ground to obtain the total horizontal voltage. The electric field assessment module calculates the electric field strength based on the total horizontal voltage, assesses the impact of the electric field on electrical equipment, and compares it with safety standards to determine whether the electric field is within an acceptable range.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the electric field evaluation method based on potential-transmission line coupling according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the electric field assessment method based on potential-transmission line coupling as described in any one of claims 1 to 7.

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