A lightning strike point voltage waveform inversion identification method and device, a terminal device, and a storage medium

Abstract

The application discloses a lightning stroke point voltage waveform inversion identification method and device, terminal equipment and a storage medium, and belongs to the technical field of power system relay protection. The method is as follows: incident waves and reflected waves at a CVT port and an overhead transmission line port, and discrete time domain voltage data of a CVT secondary side during lightning stroke are acquired to calculate a voltage transmission characteristic inverse function; then, according to the voltage transmission characteristic inverse function and a preset fitting order, optimal poles and optimal remainders are calculated, and a time domain voltage state space equation set is constructed; finally, the time domain voltage state space equation set is converted into a discrete state space equation, and lightning stroke point discrete time domain voltage data is calculated. Through implementation of the application, the problem that the accuracy of lightning fault voltage information directly obtained from the CVT is low due to the distortion of the secondary side output signal of the CVT under the action of lightning impulse voltage in the prior art can be solved.

Description

Technical Field

[0001] This invention relates to the field of power system relay protection technology, and in particular to a method, device, terminal equipment and storage medium for identifying voltage waveforms at lightning strike points. Background Technology

[0002] In high-voltage transmission line faults in power systems, faults caused directly or indirectly by lightning strikes account for approximately 40%–70% of the total number of faults. In other words, lightning strikes are one of the main causes of transmission line faults, which may damage the insulation and electrical equipment of the transmission lines, and even cause power outages and unsafe accidents.

[0003] In the existing technology, CVT (capacitive voltage transformer) is commonly used as a voltage measurement device widely used in power systems. However, under the action of high-frequency, high-amplitude lightning impulse voltage, the output signal on its secondary side is affected by the voltage transmission characteristics and will be distorted, resulting in the problem of low accuracy of lightning fault voltage information obtained directly from CVT in the existing technology. Summary of the Invention

[0004] This invention provides a method, apparatus, terminal equipment, and storage medium for identifying lightning strike point voltage waveform inversion, which can solve the problem in the prior art where the secondary side output signal of the CVT will be distorted under the action of lightning impulse voltage, resulting in low accuracy of lightning fault voltage information obtained directly from the CVT.

[0005] An embodiment of the present invention provides a method for inverting and identifying voltage waveforms at a lightning strike point, comprising: Acquire the first incident wave and the first reflected wave at the CVT port, the second incident wave and the second reflected wave at the overhead transmission line port, and the discrete time-domain voltage data of the CVT secondary side during a lightning strike. Based on the first incident wave, the first reflected wave, the second incident wave, and the second reflected wave, the inverse function of the voltage transmission characteristics of the preset port cascade model is calculated; wherein, the preset port cascade model is obtained by cascading the CVT and the overhead transmission line, and the overhead transmission line is located between the primary side of the CVT and the lightning strike point. Based on the inverse function of the voltage transfer characteristic and the preset fitting order, the optimal poles and the optimal residues are calculated. Based on the optimal poles, optimal residues, and a preset fitting order, construct the time-domain voltage state-space equations of the inverse function of the voltage transfer characteristic. The above time-domain voltage state-space equations are transformed into discrete state-space equations. Based on the above discrete time-domain voltage data of the CVT secondary side and the above discrete state-space equations, the discrete time-domain voltage data at the lightning strike point is calculated. Then, the lightning strike point voltage waveform is generated based on the above discrete time-domain voltage data at the lightning strike point.

[0006] Furthermore, based on the first incident wave, the first reflected wave, the second incident wave, and the second reflected wave, the inverse function of the voltage transfer characteristic of the preset port cascade model is calculated, including: Based on the first incident wave and the first reflected wave, the inverse function of CVT voltage transmission characteristics is constructed. Based on the second incident wave and the second reflected wave, the inverse function of the voltage transmission characteristics of the transmission line is constructed. The product of the above-mentioned inverse function of CVT voltage transmission characteristics and the above-mentioned inverse function of transmission line voltage transmission characteristics is taken as the above-mentioned inverse function of voltage transmission characteristics.

[0007] Furthermore, based on the first incident wave and the first reflected wave, the inverse function of the CVT voltage transfer characteristic is constructed, including: Based on the first incident wave and the first reflected wave, a first scattering parameter matrix is ​​constructed; Based on the first scattering parameter matrix mentioned above, a positive function of CVT voltage transfer characteristics is constructed. The reciprocal of the positive function of the CVT voltage transfer characteristic is taken as the inverse function of the CVT voltage transfer characteristic.

[0008] Furthermore, based on the second incident wave and the second reflected wave, the inverse function of the transmission line voltage transmission characteristics is constructed, including: Based on the second incident wave and the second reflected wave, construct the second scattering parameter matrix; Based on the second scattering parameter matrix mentioned above, a positive function of the voltage transmission characteristics of the transmission line is constructed. The reciprocal of the positive function of the voltage transmission characteristics of the above transmission lines is taken as the inverse function of the voltage transmission characteristics of the above transmission lines.

[0009] Furthermore, based on the aforementioned inverse function of voltage transfer characteristics and a preset fitting order, the optimal poles and optimal residues are calculated, including: Obtain a preset number of initial poles and a preset number of initial residues for the fitting order; wherein, all initial poles are conjugate poles; Based on the above-mentioned preset fitting order, all initial poles, all initial residues, and the above-mentioned inverse voltage transfer characteristic function, the function solution operation is repeated until the current complex frequency domain function converges. The current pole and the current residue are then taken as the optimal pole and the optimal residue. The above function solving operations include: Obtain the current pole and the current residue; where the initial pole is the initial pole mentioned above, and the initial residue is the initial residue mentioned above; Based on the current poles, current residues, the inverse function of the voltage transfer characteristic, and the preset fitting order, the current complex frequency domain function corresponding to the inverse function of the voltage transfer characteristic is constructed. Based on the current poles, current residues, and the preset fitting order, the value of the current complex frequency domain function is calculated, and the convergence of the current complex frequency domain function is determined based on the value of the current complex frequency domain function. If the current complex frequency domain function does not converge, the current auxiliary function corresponding to the voltage transfer characteristic inverse function is constructed based on the current pole, the current residue, the voltage transfer characteristic inverse function and the preset fitting order. Based on the current auxiliary function and the current complex frequency domain function, the updated poles and the updated residues are calculated.

[0010] Furthermore, based on the current auxiliary function and the current complex frequency domain function, the updated poles and updated residues are calculated, including: The updated poles are calculated based on the current auxiliary function; The updated residues are calculated based on the updated poles and the current complex frequency domain function.

[0011] Based on the above method embodiments, the present invention provides a corresponding terminal device embodiment; The present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the lightning strike point voltage waveform inversion and identification method described in any embodiment of the present invention.

[0012] Based on the above method embodiments, the present invention provides a corresponding storage medium embodiment; The present invention provides a storage medium including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the lightning strike point voltage waveform inversion and identification method described in any embodiment of the present invention.

[0013] The embodiments of the present invention have the following beneficial effects: This invention provides a method, apparatus, and terminal device for identifying voltage waveforms at lightning strike points. The method includes: acquiring a first incident wave and a first reflected wave at a CVT port, a second incident wave and a second reflected wave at an overhead transmission line port, and discrete time-domain voltage data of the CVT secondary side at the time of a lightning strike; subsequently, based on the first incident wave, the first reflected wave, the second incident wave, and the second reflected wave, calculating the inverse function of the voltage transfer characteristic of a preset port cascade model; wherein the preset port cascade model is based on the cascading of the CVT and the overhead transmission line, and the overhead transmission line is located at one of the CVT's... Between the secondary side and the lightning strike point; then, based on the aforementioned inverse voltage transfer characteristic function and the preset fitting order, the optimal poles and optimal residues are calculated; subsequently, based on the optimal poles, optimal residues, and the preset fitting order, a time-domain voltage state-space equation set of the aforementioned inverse voltage transfer characteristic function is constructed; finally, the aforementioned time-domain voltage state-space equation set is transformed into a discrete state-space equation, and based on the aforementioned CVT secondary side discrete time-domain voltage data and the aforementioned discrete state-space equation, the discrete time-domain voltage data at the lightning strike point is calculated, and then the lightning strike point voltage waveform is generated based on the aforementioned discrete time-domain voltage data at the lightning strike point. Therefore, this invention determines the poles and residues of the time-domain voltage state-space equation set based on the inverse function of the voltage transfer characteristics of the pre-constructed port cascaded model. Subsequently, the time-domain voltage state-space equation set is discretized and then the discrete time-domain voltage data of the CVT secondary side is input to solve the problem, thereby obtaining the discrete time-domain voltage data at the lightning strike point. Thus, by constructing the time-domain voltage state-space equation set and combining it with the discrete time-domain voltage data of the CVT secondary side, this invention enables the solution of the discrete time-domain voltage data at the lightning strike point even when the discrete time-domain voltage data of the CVT secondary side has been distorted, thereby improving the accuracy of obtaining lightning fault voltage information. Attached Figure Description

[0014] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a flowchart illustrating a lightning strike point voltage waveform inversion and identification method provided in an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of a preset port cascading model provided in an embodiment of the present invention.

[0017] Figure 3 This is a schematic diagram of the structure of a lightning strike point voltage waveform inversion and identification device provided in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0020] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0023] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0024] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0025] See Figure 1 To address the problem in existing technologies where the secondary output signal of a CVT is distorted under lightning impulse voltage, resulting in low accuracy of lightning fault voltage information directly obtained from the CVT, an embodiment of the present invention provides a method for lightning strike point voltage waveform inversion and identification, comprising: Step S101: Obtain the first incident wave and the first reflected wave at the CVT port, the second incident wave and the second reflected wave at the overhead transmission line port, and the discrete time-domain voltage data of the CVT secondary side during lightning strike. Specifically, the two ports of the vector network analyzer are connected to the primary and secondary ports of the CVT, respectively. The test frequency band is set, scattered waves are injected into the two ports of the CVT, and the first incident wave and the first reflected wave are obtained by scanning and measuring.

[0026] Specifically, the two ports of the vector network analyzer are connected to the primary and secondary ports of an overhead transmission line of length L, respectively. The test frequency band is set, scattered waves are injected into the two ports of the line, and the second incident wave and the second reflected wave are obtained by scanning and measuring.

[0027] Step S102: Based on the first incident wave, the first reflected wave, the second incident wave, and the second reflected wave, calculate the inverse function of the voltage transmission characteristics of the preset port cascade model; wherein, the preset port cascade model is obtained by cascading the CVT and the overhead transmission line, and the overhead transmission line is located between the primary side of the CVT and the lightning strike point. Specifically, disregarding the mutual influence between internal components, the overhead transmission line of length L connecting the CVT, its primary side, and the lightning strike point is represented by the aforementioned pre-defined port cascade model. A schematic diagram of the pre-defined port cascade model is shown below. Figure 2 As shown, Figure 2 "in "This represents the current flowing out of the overhead transmission line port corresponding to U1(s)," "This represents the current flowing into the overhead transmission line port corresponding to U2(s)," "U3(s)" represents the current flowing into the CVT two-port network, "Port 1" is the primary side port of the CVT, and "Port 2" is the secondary side port of the CVT. The expression for the preset port cascade model is: In the formula, s represents the variable in the Laplace transform, and represents the complex variable in the complex plane. This represents the voltage waveform at the lightning strike point in the frequency domain. This represents the voltage waveform on the primary side of the CVT in the frequency domain. This represents the inverse function of the voltage transmission characteristics of a transmission line. This represents the inverse function of CVT voltage transfer characteristics. This represents the voltage waveform on the secondary side of the CVT in the frequency domain.

[0028] In a preferred embodiment, the calculation of the inverse voltage transfer characteristic function of the preset port cascade model based on the first incident wave, the first reflected wave, the second incident wave, and the second reflected wave includes: Based on the first incident wave and the first reflected wave, the inverse function of CVT voltage transmission characteristics is constructed. Based on the second incident wave and the second reflected wave, the inverse function of the voltage transmission characteristics of the transmission line is constructed. The product of the above-mentioned inverse function of CVT voltage transmission characteristics and the above-mentioned inverse function of transmission line voltage transmission characteristics is taken as the above-mentioned inverse function of voltage transmission characteristics.

[0029] Specifically, after obtaining the inverse function of CVT voltage transmission characteristics and the inverse function of transmission line voltage transmission characteristics, multiplying the two point-to-point yields the aforementioned inverse function of voltage transmission characteristics for the entire preset port cascade model.

[0030] Preferably, this embodiment decomposes the complex cascaded system comprising a CVT and an overhead transmission line, constructing separate inverse functions for the CVT voltage transfer characteristics and the transmission line voltage transfer characteristics. This approach decomposes the original problem of solving the inverse function of a high-order, strongly coupled, and nonlinear cascaded system into two relatively independent sub-problems with clear physical meaning and lower order. By performing targeted inverse modeling of the electromagnetic transient processes within the CVT and the traveling wave propagation process of the transmission line, the numerical instability and computational explosion problems caused by directly performing high-dimensional matrix inversion or complex frequency domain fitting on the entire cascaded system are avoided, significantly reducing the complexity of the algorithm implementation and the difficulty of programming. Furthermore, since CVTs and transmission lines typically exhibit pole and zero distributions of different orders of magnitude in the frequency domain—for example, CVTs mainly exhibit low- to mid-frequency resonant characteristics, while transmission lines exhibit wide-band traveling wave propagation characteristics—if they are directly approximated as a single system using rational functions, the state-space matrix is ​​prone to ill-conditioned problems due to the excessively dispersed distribution of poles in the complex plane. This scheme obtains two sub-inverse functions of lower order and relatively concentrated frequency bands, and then synthesizes the overall inverse function through multiplication. In the subsequent construction of the time-domain voltage state-space equations, it effectively avoids the numerical ill-conditioning problem of high-order matrices, ensures the numerical stability of the discrete state-space equations in the iterative solution process, and makes the reconstruction result of the lightning strike voltage waveform smoother and more convergent.

[0031] In this preferred embodiment, the inverse function of voltage transmission characteristics is obtained by multiplying the inverse function of CVT voltage transmission characteristics with the inverse function of transmission line voltage transmission characteristics point-to-point.

[0032] In another preferred embodiment, the above-mentioned construction of the inverse function of CVT voltage transfer characteristics based on the first incident wave and the first reflected wave includes: Based on the first incident wave and the first reflected wave, a first scattering parameter matrix is ​​constructed; Specifically, the first scattering parameter matrix is ​​constructed using the following formula: In the formula, This represents the reflected wave emitted from the primary side port of the CVT. This represents the reflected wave emitted from the secondary side port of the CVT. This represents one of the sub-incident waves of the first incident wave. The reflection component at the primary side port of the CVT. This represents another sub-incident wave of the first incident wave. The component was successfully transmitted to the primary side port of the CVT. This represents another sub-incident wave of the first incident wave. The component was successfully transmitted to the secondary side port of the CVT. This represents one of the sub-incident waves of the first incident wave. The reflection component at the secondary side port of the CVT. and These represent the two sub-incident waves in the first incident wave. This represents the first scattering parameter matrix.

[0033] Based on the first scattering parameter matrix mentioned above, a positive function of CVT voltage transfer characteristics is constructed. Specifically, the positive function of CVT voltage transfer characteristics is constructed using the following formula: In the formula, This represents a positive function of the voltage transfer characteristics of a CVT.

[0034] The reciprocal of the positive function of the CVT voltage transfer characteristic is taken as the inverse function of the CVT voltage transfer characteristic.

[0035] Specifically, the inverse function of the CVT voltage transfer characteristic is obtained through the following formula: In this preferred embodiment, the inverse function of CVT voltage transfer characteristics is constructed based on the first incident wave and the first reflected wave.

[0036] In another preferred embodiment, the above-mentioned construction of the inverse function of the transmission line voltage transmission characteristics based on the second incident wave and the second reflected wave includes: Based on the second incident wave and the second reflected wave, construct the second scattering parameter matrix; Specifically, similar to the construction process of the first scattering parameter matrix, the elements in the second scattering parameter matrix can be calculated based on the two sub-incident waves in the second incident wave, and then the second scattering parameter matrix can be obtained.

[0037] Based on the second scattering parameter matrix mentioned above, a positive function of the voltage transmission characteristics of the transmission line is constructed. Specifically, the positive function of voltage transmission characteristics of transmission lines is expressed by the following formula: In the formula, This represents a positive function of the voltage transmission characteristics of a transmission line. This represents the reflection component of one of the sub-incident waves of the second incident wave at the primary side port of the overhead transmission line. This indicates the component of the second incident wave that successfully reaches the primary side port of the overhead transmission line. This indicates the component of the second incident wave that successfully reaches the secondary side port of the overhead transmission line. This represents the reflection component of one of the sub-incident waves of the second incident wave at the secondary side port of the overhead transmission line.

[0038] The reciprocal of the positive function of the voltage transmission characteristics of the above transmission lines is taken as the inverse function of the voltage transmission characteristics of the above transmission lines.

[0039] Specifically, the inverse function of the voltage transmission characteristic of the transmission line is obtained through the following formula: In this preferred embodiment, an inverse function of the voltage transmission characteristics of the transmission line is constructed based on the second incident wave and the second reflected wave.

[0040] Step S103: Based on the above inverse voltage transfer characteristic function and the preset fitting order, calculate the optimal poles and the optimal residues; Specifically, the preset fitting order is related to the number of waveform resonance points of the data being fitted.

[0041] In a preferred embodiment, the calculation of the optimal poles and optimal residues based on the inverse function of the voltage transfer characteristic and a preset fitting order includes: Obtain a preset number of initial poles and a preset number of initial residues for the fitting order; wherein, all initial poles are conjugate poles; Specifically, to ensure fitting accuracy, within a given frequency range, the preset fitting order should be greater than the total number of resonant points in the frequency response. All initial poles are set as conjugate poles to ensure the fitted function curve is smooth, with both its real and imaginary parts exhibiting a logarithmic frequency distribution within the range of 50Hz to 1MHz.

[0042] Based on the above-mentioned preset fitting order, all initial poles, all initial residues, and the above-mentioned inverse voltage transfer characteristic function, the function solution operation is repeated until the current complex frequency domain function converges. The current pole and the current residue are then taken as the optimal pole and the optimal residue. The above function solving operations include: Obtain the current pole and the current residue; where the initial pole is the initial pole mentioned above, and the initial residue is the initial residue mentioned above; Based on the current poles, current residues, the inverse function of the voltage transfer characteristic, and the preset fitting order, the current complex frequency domain function corresponding to the inverse function of the voltage transfer characteristic is constructed. Specifically, the obtained inverse voltage transfer characteristic function is actually a discrete data point with different values ​​at different frequencies. It cannot be directly used to solve the time-domain voltage. The vector matching method is required to fit the inverse voltage transfer characteristic function into the corresponding complex frequency domain function.

[0043] Specifically, after fitting using the vector matching method, the inverse function of the voltage transfer characteristic is... The corresponding complex frequency domain function is expressed as follows: In the formula, This indicates the preset fitting order, where k represents the k-th fitting order. This represents the residue corresponding to the k-th order of fitting. Let represent the poles corresponding to the k-th order of fitting, and d represent the constant term.

[0044] Based on the current poles, current residues, and the preset fitting order, the value of the current complex frequency domain function is calculated, and the convergence of the current complex frequency domain function is determined based on the value of the current complex frequency domain function. If the current complex frequency domain function does not converge, the current auxiliary function corresponding to the voltage transfer characteristic inverse function is constructed based on the current pole, the current residue, the voltage transfer characteristic inverse function and the preset fitting order. Specifically, firstly, based on the same residues and poles as the complex frequency domain function, a new unknown function is constructed. : In the formula, express The residue, express and The expressions have the same initial poles.

[0045] Then, by approximating the above equation, we obtain the auxiliary function mentioned above: Based on the current auxiliary function and the current complex frequency domain function, the updated poles and the updated residues are calculated.

[0046] In this preferred embodiment, the optimal residue and the optimal pole are obtained by iteratively solving the complex frequency domain function until the function converges.

[0047] In another preferred embodiment, the above-mentioned calculation of the updated poles and updated residues based on the current auxiliary function and the current complex frequency domain function includes: The updated poles are calculated based on the current auxiliary function; Specifically, by substituting a set of measured discrete data points into an auxiliary function, an overdetermined linear optimization problem can be constructed. Solving for the unknown parameters using the least squares method yields a new set of poles for the rational function expression in the complex frequency domain. The measured discrete data points are obtained by measuring the incident and reflected waves at the CVT break point and the overhead transmission line break point, calculating the inverse voltage transfer characteristic function values ​​for the overhead transmission line and the CVT, and then multiplying the two values.

[0048] The updated residues are calculated based on the updated poles and the current complex frequency domain function.

[0049] Specifically, by substituting the new set of poles obtained in the previous step into the complex frequency domain function, another overdetermined linear optimization problem can be constructed based on the measured voltage transfer characteristic data. The least squares method can then be used to solve for a new set of residues.

[0050] In this preferred embodiment, the updated poles and the updated residues are calculated by computing the auxiliary function and the complex frequency domain function.

[0051] Step S104: Construct the time-domain voltage state-space equations of the inverse function of the voltage transfer characteristic based on the optimal poles, optimal residues, and preset fitting order. Specifically, based on the optimal poles, optimal residues, and a preset fitting order, the inverse function of the voltage transfer characteristic is rewritten in matrix form: In the formula, C represents 1× A row vector of order I, whose elements are the optimal poles, where I represents the identity matrix and A represents the... A diagonal matrix of order B, where the diagonal elements are the optimal residues. A column vector of order ×1, with all elements being 1, where D=d, represents a linear term.

[0052] Subsequently, the above matrix form is compared with... Simultaneous equations, and the introduction of state variables. By performing a Laplace transform, the above matrix form can be presented as a continuous time-domain voltage state-space equation set: In the formula, Represents state variables Regarding time The first derivative of , where x represents the introduced state variable. This represents continuous CVT secondary-side voltage data in the time domain. This represents the actual voltage data at the lightning strike point of a continuous overhead transmission line in the time domain.

[0053] Step S105: Transform the above time-domain voltage state-space equations into discrete state-space equations, and calculate the discrete time-domain voltage data at the lightning strike point based on the above CVT secondary side discrete time-domain voltage data and the above discrete state-space equations. Then, generate the lightning strike point voltage waveform based on the above discrete time-domain voltage data at the lightning strike point.

[0054] Specifically, to enable the data to be processed and calculated in the actual simulation system, the central difference method is used to transform the continuous time-domain voltage state-space equations into discrete state-space equations. The input is the discrete time-domain voltage data of the CVT secondary side, and new state variables are defined. The output is the discrete-time voltage data at the lightning strike point, which realizes the inversion of the voltage waveform on the secondary side of the CVT equipment in the substation to obtain the actual voltage waveform at the lightning strike point of the overhead transmission line with a distance L from the primary side of the CVT. The discrete state-space equation after discretization is: In the formula, This represents the newly defined state variable, and k' represents the time step, k'=1, 2, 3, ... , , and These are all intermediate quantities in the calculation process. Indicates the unit sampling time. This represents the discrete-time voltage data at the point of lightning strike. This represents the discrete time-domain voltage data of the CVT secondary side.

[0055] Specifically, after obtaining the discrete time-domain voltage data at the lightning strike point, the corresponding voltage waveform can be further obtained, which is the inverted lightning strike point voltage waveform.

[0056] Preferably, after obtaining the discrete time-domain voltage data at the lightning strike point, analyzing the overvoltage information (such as amplitude, steepness, oscillation frequency, etc.) is of profound significance for optimizing the coordination of surge arresters and insulation, improving the design of grounding devices, enhancing the lightning protection level of power systems, strengthening fault diagnosis and accident tracing capabilities, supporting the study of power system transient processes, promoting intelligent monitoring and big data applications, and ensuring the safe and economical operation of the power grid.

[0057] Preferably, this invention synchronously acquires multidimensional traveling wave data (including incident and reflected waves) from CVT ports and overhead transmission line ports, and constructs an accurate inverse function of voltage transmission characteristics based on a physical model of the cascaded CVT and overhead transmission line. Compared to traditional methods that rely solely on data from a single measurement point or ignore the complex electromagnetic coupling effects between the line and the CVT, this invention fully considers the reflection and refraction process of the traveling wave along the transmission path and the broadband transmission characteristics within the CVT, using the inverse function to accurately compensate for amplitude attenuation and phase distortion from the lightning strike point to the secondary side measurement point. By calculating the optimal poles and residues, a high-precision time-domain state-space equation set is constructed, ensuring that the final reconstructed voltage waveform at the lightning strike point closely approximates the actual physical process in terms of amplitude accuracy, wavefront steepness, and waveform characteristics, providing a reliable data foundation for the accurate analysis of lightning strike faults.

[0058] Based on the above method embodiments, the present invention provides corresponding apparatus embodiments.

[0059] like Figure 3 As shown, an embodiment of the present invention provides a lightning strike point voltage waveform inversion and identification device, comprising: Data acquisition module, inverse function construction module, pole and residue identification module, equation system construction module, and lightning strike point voltage calculation module; The aforementioned data acquisition module is used to acquire the first incident wave and the first reflected wave at the CVT port, the second incident wave and the second reflected wave at the overhead transmission line port, and the discrete time-domain voltage data of the CVT secondary side during a lightning strike. Specifically, the two ports of the vector network analyzer are connected to the primary and secondary ports of the CVT, respectively. The test frequency band is set, and scattered waves are injected into the two ports of the CVT. The first incident wave and the first reflected wave are obtained by scanning and measuring based on the data acquisition module.

[0060] Specifically, the two ports of the vector network analyzer are connected to the primary and secondary ports of an overhead transmission line of length L, respectively. The test frequency band is set, scattered waves are injected into the two ports of the line, and the second incident wave and the second reflected wave are obtained by scanning and measuring based on the data acquisition module.

[0061] The aforementioned inverse function construction module is used to calculate the voltage transmission characteristic inverse function of the preset port cascade model based on the first incident wave, the first reflected wave, the second incident wave, and the second reflected wave; wherein, the aforementioned preset port cascade model is obtained by cascading the CVT and the aforementioned overhead transmission line, and the aforementioned overhead transmission line is located between the primary side of the CVT and the lightning strike point; Specifically, disregarding the mutual influence between internal components, the overhead transmission line of length L connecting the CVT, its primary side, and the lightning strike point is represented by the aforementioned preset port cascade model. The expression for the preset port cascade model is: In the formula, s represents the variable in the Laplace transform, and represents the complex variable in the complex plane. This represents the voltage waveform at the lightning strike point in the frequency domain. This represents the voltage waveform on the primary side of the CVT in the frequency domain. This represents the inverse function of the voltage transmission characteristics of a transmission line. This represents the inverse function of CVT voltage transfer characteristics. This represents the voltage waveform on the secondary side of the CVT in the frequency domain.

[0062] The aforementioned pole and residue identification module is used to calculate the optimal pole and the optimal residue based on the inverse function of the voltage transfer characteristic and the preset fitting order. Specifically, the preset fitting order is related to the number of waveform resonance points of the data being fitted.

[0063] The above equation construction module is used to construct the time-domain voltage state-space equations of the inverse function of the voltage transfer characteristic based on the optimal poles, the optimal residues, and the preset fitting order. Specifically, based on the optimal poles, optimal residues, and a preset fitting order, the inverse function of the voltage transfer characteristic is rewritten in matrix form: In the formula, C represents 1× A row vector of order I, whose elements are the optimal poles, where I represents the identity matrix and A represents the... A diagonal matrix of order B, where the diagonal elements are the optimal residues. A column vector of order ×1, with all elements being 1, where D=d, represents a linear term.

[0064] Subsequently, the above matrix form is compared with... Simultaneous equations, and the introduction of state variables. By performing a Laplace transform, the above matrix form can be presented as a continuous time-domain voltage state-space equation set: In the formula, Represents state variables Regarding time The first derivative of , where x represents the introduced state variable. This represents continuous CVT secondary-side voltage data in the time domain. This represents the actual voltage data at the lightning strike point of a continuous overhead transmission line in the time domain.

[0065] The aforementioned lightning strike point voltage calculation module is used to transform the aforementioned time-domain voltage state-space equations into discrete state-space equations, and calculate the discrete time-domain voltage data at the lightning strike point based on the aforementioned CVT secondary side discrete time-domain voltage data and the aforementioned discrete state-space equations. Then, it generates the lightning strike point voltage waveform based on the aforementioned discrete time-domain voltage data at the lightning strike point.

[0066] Specifically, to enable the data to be processed and calculated in the actual simulation system, the central difference method is used to transform the continuous time-domain voltage state-space equations into discrete state-space equations. The input is the discrete time-domain voltage data of the CVT secondary side, and new state variables are defined. The output is the discrete-time voltage data at the lightning strike point, which realizes the inversion of the voltage waveform on the secondary side of the CVT equipment in the substation to obtain the actual voltage waveform at the lightning strike point of the overhead transmission line with a distance L from the primary side of the CVT. The discrete state-space equation after discretization is: In the formula, This represents the newly defined state variable, and k' represents the time step, k'=1, 2, 3, ... , , and These are all intermediate quantities in the calculation process. Indicates the unit sampling time. This represents the discrete-time voltage data at the point of lightning strike. This represents the discrete time-domain voltage data of the CVT secondary side.

[0067] Specifically, after obtaining the discrete time-domain voltage data at the lightning strike point, the corresponding voltage waveform can be further obtained, which is the inverted lightning strike point voltage waveform.

[0068] Preferably, after obtaining the discrete time-domain voltage data at the lightning strike point, analyzing the overvoltage information (such as amplitude, steepness, oscillation frequency, etc.) is of profound significance for optimizing the coordination of surge arresters and insulation, improving the design of grounding devices, enhancing the lightning protection level of power systems, strengthening fault diagnosis and accident tracing capabilities, supporting the study of power system transient processes, promoting intelligent monitoring and big data applications, and ensuring the safe and economical operation of the power grid.

[0069] In a preferred embodiment, the inverse function construction module includes: The CVT voltage transfer characteristic inverse function construction unit, the transmission line voltage transfer characteristic inverse function construction unit, and the voltage transfer characteristic inverse function calculation unit; The aforementioned CVT voltage transmission characteristic inverse function construction unit is used to construct the CVT voltage transmission characteristic inverse function based on the aforementioned first incident wave and first reflected wave. The aforementioned inverse function construction unit for transmission line voltage transmission characteristics is used to construct the inverse function for transmission line voltage transmission characteristics based on the aforementioned second incident wave and second reflected wave. The aforementioned voltage transmission characteristic inverse function calculation unit is used to take the product of the aforementioned CVT voltage transmission characteristic inverse function and the aforementioned transmission line voltage transmission characteristic inverse function as the aforementioned voltage transmission characteristic inverse function.

[0070] Specifically, after obtaining the inverse function of CVT voltage transmission characteristics and the inverse function of transmission line voltage transmission characteristics, multiplying the two point-to-point yields the aforementioned inverse function of voltage transmission characteristics for the entire preset port cascade model.

[0071] Preferably, this embodiment decomposes the complex cascaded system including CVT and overhead transmission line into two sub-problems. The inverse function of CVT voltage transmission characteristics and the inverse function of transmission line voltage transmission characteristics are constructed separately. The original problem of solving the inverse function of the high-order, strongly coupled, and nonlinear cascaded system is decomposed into two relatively independent sub-problems with clear physical meaning and lower order. This avoids the numerical instability and computational explosion caused by directly performing high-dimensional matrix inversion or complex frequency domain fitting on the whole cascaded system, and greatly reduces the complexity of algorithm implementation and programming difficulty.

[0072] In another preferred embodiment, the above-mentioned CVT voltage transfer characteristic inverse function construction unit includes: The first scattering parameter matrix constructs the sub-unit, the positive function of CVT voltage transfer characteristics constructs the sub-unit, and the inverse function of CVT voltage transfer characteristics determines the sub-unit; The aforementioned first scattering parameter matrix construction sub-unit is used to construct the first scattering parameter matrix based on the aforementioned first incident wave and first reflected wave; Specifically, the first scattering parameter matrix is ​​constructed using the following formula: In the formula, This represents the reflected wave emitted from the primary side port of the CVT. This represents the reflected wave emitted from the secondary side port of the CVT. This represents one of the sub-incident waves of the first incident wave. The reflection component at the primary side port of the CVT. This represents another sub-incident wave of the first incident wave. The component was successfully transmitted to the primary side port of the CVT. This represents another sub-incident wave of the first incident wave. The component was successfully transmitted to the secondary side port of the CVT. This represents one of the sub-incident waves of the first incident wave. The reflection component at the secondary side port of the CVT. and These represent the two sub-incident waves in the first incident wave. This represents the first scattering parameter matrix.

[0073] The aforementioned CVT voltage transfer characteristic positive function construction subunit is used to construct the CVT voltage transfer characteristic positive function based on the aforementioned first scattering parameter matrix; Specifically, the positive function of CVT voltage transfer characteristics is constructed using the following formula: In the formula, This represents a positive function of the voltage transfer characteristics of a CVT.

[0074] The aforementioned CVT voltage transmission characteristic inverse function determination subunit is used to take the reciprocal of the aforementioned CVT voltage transmission characteristic positive function as the aforementioned CVT voltage transmission characteristic inverse function.

[0075] Specifically, the inverse function of the CVT voltage transfer characteristic is obtained through the following formula: In another preferred embodiment, the above-mentioned inverse function construction unit for transmission line voltage transmission characteristics includes: The second scattering parameter matrix is ​​used to construct sub-units, the positive function of the voltage transmission characteristic of the transmission line is used to construct sub-units, and the inverse function of the voltage transmission characteristic of the transmission line is used to determine sub-units; The aforementioned second scattering parameter matrix construction sub-unit is used to construct the second scattering parameter matrix based on the aforementioned second incident wave and second reflected wave; Specifically, similar to the construction process of the first scattering parameter matrix, the elements in the second scattering parameter matrix can be calculated based on the two sub-incident waves in the second incident wave, and then the second scattering parameter matrix can be obtained.

[0076] The aforementioned sub-unit for constructing the positive function of voltage transmission characteristics of transmission lines is used to construct the positive function of voltage transmission characteristics of transmission lines based on the aforementioned second scattering parameter matrix; Specifically, the positive function of voltage transmission characteristics of transmission lines is expressed by the following formula: In the formula, This represents a positive function of the voltage transmission characteristics of a transmission line. This represents the reflection component of one of the sub-incident waves of the second incident wave at the primary side port of the overhead transmission line. This indicates the component of the second incident wave that successfully reaches the primary side port of the overhead transmission line. This indicates the component of the second incident wave that successfully reaches the secondary side port of the overhead transmission line. This represents the reflection component of one of the sub-incident waves of the second incident wave at the secondary side port of the overhead transmission line.

[0077] The aforementioned inverse function determination subunit for the voltage transmission characteristics of the transmission line is used to take the reciprocal of the positive function of the voltage transmission characteristics of the transmission line as the inverse function of the voltage transmission characteristics of the transmission line.

[0078] Specifically, the inverse function of the voltage transmission characteristic of the transmission line is obtained through the following formula: In another preferred embodiment, the pole and residue identification module includes: Initial data acquisition unit and function solving unit; The aforementioned initial data acquisition unit is used to acquire a preset number of initial poles and a preset number of initial residues of a predetermined fitting order; wherein, all initial poles are conjugate poles; Specifically, to ensure fitting accuracy, within a given frequency range, the preset fitting order should be greater than the total number of resonant points in the frequency response. All initial poles are set as conjugate poles to ensure the fitted function curve is smooth, with both its real and imaginary parts exhibiting a logarithmic frequency distribution within the range of 50Hz to 1MHz.

[0079] The function solving unit described above is used to repeatedly perform the function solving operation based on the preset fitting order, all initial poles, all initial residues, and the inverse function of the voltage transfer characteristic, until the current complex frequency domain function converges, and the current poles and current residues are taken as the optimal poles and optimal residues. The above function solving operations include: Obtain the current pole and the current residue; where the initial pole is the initial pole mentioned above, and the initial residue is the initial residue mentioned above; Based on the current poles, current residues, the inverse function of the voltage transfer characteristic, and the preset fitting order, the current complex frequency domain function corresponding to the inverse function of the voltage transfer characteristic is constructed. Specifically, the obtained inverse voltage transfer characteristic function is actually a discrete data point with different values ​​at different frequencies. It cannot be directly used to solve the time-domain voltage. The vector matching method is required to fit the inverse voltage transfer characteristic function into the corresponding complex frequency domain function.

[0080] Specifically, after fitting using the vector matching method, the inverse function of the voltage transfer characteristic is... The corresponding complex frequency domain function is expressed as follows: In the formula, This indicates the preset fitting order, where k represents the k-th fitting order. This represents the residue corresponding to the k-th order of fitting. Let represent the poles corresponding to the k-th order of fitting, and d represent the constant term.

[0081] Based on the current poles, current residues, and the preset fitting order, the value of the current complex frequency domain function is calculated, and the convergence of the current complex frequency domain function is determined based on the value of the current complex frequency domain function. If the current complex frequency domain function does not converge, the current auxiliary function corresponding to the voltage transfer characteristic inverse function is constructed based on the current pole, the current residue, the voltage transfer characteristic inverse function and the preset fitting order. Based on the current auxiliary function and the current complex frequency domain function, the updated poles and the updated residues are calculated.

[0082] Specifically, firstly, based on the same residues and poles as the complex frequency domain function, a new unknown function is constructed. : In the formula, express The residue, express and The expressions have the same initial poles.

[0083] Then, by approximating the above equation, we obtain the auxiliary function mentioned above: Based on the current auxiliary function and the current complex frequency domain function, the updated poles and the updated residues are calculated.

[0084] In another preferred embodiment, the above-mentioned function solving unit includes: Pole update sub-unit and residue update sub-unit; The aforementioned pole update subunit is used to calculate the updated poles based on the current auxiliary function; Specifically, by substituting a set of measured discrete data points into an auxiliary function, an overdetermined linear optimization problem can be constructed. Solving for the unknown parameters using the least squares method yields a new set of poles for the rational function expression in the complex frequency domain. The measured discrete data points are obtained by measuring the incident and reflected waves at the CVT break point and the overhead transmission line break point, calculating the inverse voltage transfer characteristic function values ​​for the overhead transmission line and the CVT, and then multiplying the two values.

[0085] The aforementioned residue update sub-unit is used to calculate the updated residue based on the updated poles and the current complex frequency domain function.

[0086] Specifically, by substituting the new set of poles obtained in the previous step into the complex frequency domain function, another overdetermined linear optimization problem can be constructed based on the measured voltage transfer characteristic data. The least squares method can then be used to solve for a new set of residues.

[0087] It should be noted that the device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationship between modules indicates that they have a communication connection, which can be implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without creative effort. The above schematic diagram is merely an example of a lightning strike point voltage waveform inversion and identification device and does not constitute a limitation on a lightning strike point voltage waveform inversion and identification device. It may include more or fewer components than shown, or combine certain components, or use different components.

[0088] Based on the above method embodiments, the present invention provides corresponding terminal device embodiments.

[0089] Another embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the lightning strike point voltage waveform inversion and identification method described in any embodiment of the present invention.

[0090] For example, in this embodiment, the computer program can be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the device. The aforementioned terminal devices may be computing devices such as desktop computers, laptops, handheld computers, and cloud servers. These devices may include, but are not limited to, processors and memory. The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. This processor is the control center of the device, connecting various parts of the device via various interfaces and lines. The aforementioned memory can be used to store the aforementioned computer programs and / or modules. The aforementioned processor implements various functions of the aforementioned device by running or executing the computer programs and / or modules stored in the aforementioned memory, and by calling data stored in the memory. The aforementioned memory may mainly include a program storage area and a data storage area, wherein the program storage area may store the operating system, at least one application program required for a function, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0091] Based on the above method embodiments, the present invention provides corresponding storage medium embodiments.

[0092] Another embodiment of the present invention provides a storage medium including a stored computer program, wherein, when the computer program is running, it controls the device where the storage medium is located to execute the lightning strike point voltage waveform inversion and identification method described in any embodiment of the present invention.

[0093] In this embodiment, the storage medium is a computer-readable storage medium, and the computer program includes computer program code, which may be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium may include any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0094] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for identifying and retrieving voltage waveforms at a lightning strike point, characterized in that, include: Acquire the first incident wave and the first reflected wave at the CVT port, the second incident wave and the second reflected wave at the overhead transmission line port, and the discrete time-domain voltage data of the CVT secondary side during a lightning strike. Based on the first incident wave, the first reflected wave, the second incident wave, and the second reflected wave, the inverse function of the voltage transmission characteristic of the preset port cascade model is calculated; wherein, the preset port cascade model is obtained by cascading the CVT and the overhead transmission line, and the overhead transmission line is located between the primary side of the CVT and the lightning strike point; Based on the inverse function of the voltage transfer characteristic and the preset fitting order, the optimal poles and the optimal residues are calculated. The time-domain voltage state-space equations of the inverse function of the voltage transfer characteristic are constructed based on the optimal poles, the optimal residues, and the preset fitting order. The time-domain voltage state-space equations are transformed into discrete state-space equations. Based on the discrete time-domain voltage data of the CVT secondary side and the discrete state-space equations, the discrete time-domain voltage data at the lightning strike point is calculated. Then, the lightning strike point voltage waveform is generated based on the discrete time-domain voltage data at the lightning strike point.

2. The lightning strike point voltage waveform inversion and identification method according to claim 1, characterized in that, The step of calculating the inverse function of the voltage transfer characteristic of the preset port cascade model based on the first incident wave, the first reflected wave, the second incident wave, and the second reflected wave includes: Based on the first incident wave and the first reflected wave, the inverse function of CVT voltage transmission characteristics is constructed; Based on the second incident wave and the second reflected wave, the inverse function of the voltage transmission characteristics of the transmission line is constructed; The product of the inverse function of the CVT voltage transmission characteristic and the inverse function of the transmission line voltage transmission characteristic is taken as the inverse function of the voltage transmission characteristic.

3. The method for inverting and identifying the voltage waveform at a lightning strike point according to claim 2, characterized in that, The step of constructing the inverse function of CVT voltage transfer characteristics based on the first incident wave and the first reflected wave includes: Based on the first incident wave and the first reflected wave, a first scattering parameter matrix is ​​constructed; A positive function of CVT voltage transfer characteristics is constructed based on the first scattering parameter matrix; The reciprocal of the positive function of the CVT voltage transfer characteristic is taken as the inverse function of the CVT voltage transfer characteristic.

4. The lightning strike point voltage waveform inversion and identification method according to claim 3, characterized in that, The step of constructing the inverse function of the transmission line voltage transmission characteristics based on the second incident wave and the second reflected wave includes: Based on the second incident wave and the second reflected wave, construct the second scattering parameter matrix; A positive function of voltage transmission characteristics of the transmission line is constructed based on the second scattering parameter matrix; The reciprocal of the positive function of the voltage transmission characteristic of the transmission line is taken as the inverse function of the voltage transmission characteristic of the transmission line.

5. The lightning strike point voltage waveform inversion and identification method according to claim 4, characterized in that, The step of calculating the optimal poles and optimal residues based on the inverse function of the voltage transfer characteristic and a preset fitting order includes: Obtain a preset number of initial poles and a preset number of initial residues for the fitting order; wherein, all initial poles are conjugate poles; Based on the preset fitting order, all initial poles, all initial residues, and the inverse function of the voltage transfer characteristic, the function solving operation is repeated until the current complex frequency domain function converges. The current pole and the current residue are then taken as the optimal pole and the optimal residue. The function solving operation includes: Obtain the current pole and the current residue; wherein, the initial pole is the initial pole and the initial residue is the initial residue; Based on the current poles, current residues, the inverse function of the voltage transfer characteristic, and the preset fitting order, the current complex frequency domain function corresponding to the inverse function of the voltage transfer characteristic is constructed. The value of the current complex frequency domain function is calculated based on the current pole, the current residue, and the preset fitting order. The convergence of the current complex frequency domain function is then determined based on the value of the current complex frequency domain function. If the current complex frequency domain function does not converge, the current auxiliary function corresponding to the voltage transfer characteristic is constructed based on the current pole, the current residue, the inverse voltage transfer characteristic function, and the preset fitting order. Based on the current auxiliary function and the current complex frequency domain function, the updated poles and the updated residues are calculated.

6. The lightning strike point voltage waveform inversion and identification method according to claim 5, characterized in that, The step of calculating the updated poles and updated residues based on the current auxiliary function and the current complex frequency domain function includes: The updated poles are calculated based on the current auxiliary function; The updated residues are calculated based on the updated poles and the current complex frequency domain function.

7. A device for inverting and identifying voltage waveforms at a lightning strike point, characterized in that, include: Data acquisition module, inverse function construction module, pole and residue identification module, equation system construction module, and lightning strike point voltage calculation module; The data acquisition module is used to acquire the first incident wave and the first reflected wave at the CVT port, the second incident wave and the second reflected wave at the overhead transmission line port, and the discrete time-domain voltage data of the CVT secondary side during lightning strike. The inverse function construction module is used to calculate the inverse voltage transmission characteristic function of the preset port cascade model based on the first incident wave, the first reflected wave, the second incident wave, and the second reflected wave; wherein the preset port cascade model is obtained by cascading the CVT and the overhead transmission line, and the overhead transmission line is located between the primary side of the CVT and the lightning strike point; The pole and residue identification module is used to calculate the optimal pole and the optimal residue based on the inverse function of the voltage transfer characteristic and a preset fitting order. The equation construction module is used to construct the time-domain voltage state-space equations of the inverse function of the voltage transfer characteristic based on the optimal poles, the optimal residues, and the preset fitting order. The lightning strike point voltage calculation module is used to transform the time-domain voltage state-space equations into discrete state-space equations, and calculate the discrete time-domain voltage data at the lightning strike point based on the discrete time-domain voltage data of the CVT secondary side and the discrete state-space equations, and then generate the lightning strike point voltage waveform based on the discrete time-domain voltage data at the lightning strike point.

8. The lightning strike point voltage waveform inversion and identification device according to claim 7, characterized in that, The inverse function construction module includes: The CVT voltage transfer characteristic inverse function construction unit, the transmission line voltage transfer characteristic inverse function construction unit, and the voltage transfer characteristic inverse function calculation unit; The CVT voltage transmission characteristic inverse function construction unit is used to construct the CVT voltage transmission characteristic inverse function based on the first incident wave and the first reflected wave. The inverse function construction unit for the voltage transmission characteristics of the transmission line is used to construct the inverse function for the voltage transmission characteristics of the transmission line based on the second incident wave and the second reflected wave. The voltage transmission characteristic inverse function calculation unit is used to take the product of the CVT voltage transmission characteristic inverse function and the transmission line voltage transmission characteristic inverse function as the voltage transmission characteristic inverse function.

9. A terminal device, characterized in that, The system includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements a lightning strike point voltage waveform inversion and identification method as described in any one of claims 1 to 6.

10. A storage medium, characterized in that, The storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device where the storage medium is located to perform a lightning strike point voltage waveform inversion and identification method as described in any one of claims 1 to 6.

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