A method and system for lightning induced overvoltage analysis of a photovoltaic array
By establishing an electromagnetic transient coupling model of the photovoltaic array, the induced voltage between the photovoltaic support and the battery string is calculated, which solves the problem of insufficient accuracy in calculating the lightning-induced overvoltage of the photovoltaic array in the existing technology, and realizes high-precision and rapid assessment of lightning-induced overvoltage.
Patent Information
- Application Number
- CN202611552031.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-10-09
- Publication Date
- 2026-11-06
AI Technical Summary
Existing assessment models for lightning-induced overvoltage of photovoltaic arrays fail to fully consider the electromagnetic coupling effect of multi-branch conductors in photovoltaic arrays, resulting in insufficient calculation accuracy and making it difficult to provide reliable basis for selecting parameters of lightning protection equipment.
An electromagnetic transient coupling model between the photovoltaic support structure, battery strings, and DC cables is established. The incident lightning electromagnetic field is calculated using the exponential decay modified transmission line model and the dipole method. The photovoltaic support structure and module frame are decomposed into multiple independent loops. An RL equivalent circuit is established to calculate the induced current and scattered field. The total magnetic field is obtained by vector superposition, and the lightning-induced overvoltage is accurately calculated.
It significantly improves the calculation accuracy of lightning-induced overvoltage of photovoltaic arrays, reduces calculation time, is suitable for rapid evaluation of large-scale photovoltaic arrays, and provides a theoretical basis for parameter selection.
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Figure CN123046472A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lightning protection technology for photovoltaic power generation systems, and particularly relates to a method and system for analyzing lightning-induced overvoltages in photovoltaic arrays. Background Technology
[0002] With the rapid development of the photovoltaic industry, the total installed capacity of photovoltaic power generation continues to grow, making the safe and stable operation of photovoltaic arrays a key challenge. Photovoltaic arrays are typically installed in open outdoor areas, occupying a large area, with high spatial exposure and a high proportion of metal structures, making them extremely vulnerable to lightning strikes. Unlike wind turbines, photovoltaic arrays are installed at lower heights, making them significantly more susceptible to induced lightning strikes than direct lightning strikes. The strong electromagnetic pulse generated during a lightning strike can induce lightning surges in the DC circuit of nearby photovoltaic arrays, with overvoltage amplitudes reaching thousands of volts.
[0003] Existing photovoltaic (PV) array lightning-induced overvoltage assessment models only consider the electromagnetic induction between the lightning electromagnetic field and the array circuit, neglecting the electromagnetic effects of other metal structures within the array. The electromagnetic coupling mechanism between the support structure and the battery strings and DC cables remains unclear. PV arrays contain numerous thin-diameter conductors within their internal wiring, and the complex structure, numerous branches, and varying spatial arrangements of the PV support structure further complicate the electromagnetic coupling mechanism between cables, supports, and frames. Traditional overhead line "field-line" coupling models are ill-suited for the complex structure of PV arrays. A new "field-line" coupling model for the lightning electromagnetic field on the multi-branch conductor structure of the PV array is needed, one that can consider the electromagnetic transient coupling effects of multiple conductors, enabling accurate assessment of lightning-induced overvoltage in PV arrays.
[0004] Therefore, there is an urgent need for a lightning strike induced overvoltage analysis method and system that can take into account the electromagnetic transient coupling effect of multi-branch conductors in photovoltaic arrays, so as to improve the calculation accuracy of lightning strike induced overvoltage of photovoltaic arrays and provide a reliable theoretical basis for the parameter selection of lightning protection equipment for photovoltaic systems. Summary of the Invention
[0005] This invention provides a method and system for analyzing lightning-induced overvoltage in photovoltaic arrays. By establishing an electromagnetic transient coupling model between the photovoltaic support, battery strings, and DC cables, the coupling effect of multiple conductors in the photovoltaic array during the electromagnetic transient process of lightning strikes is fully considered, significantly improving the calculation accuracy of lightning-induced overvoltage in photovoltaic arrays.
[0006] In a first aspect, the present invention provides a method for analyzing lightning-induced overvoltage in photovoltaic arrays, comprising: Obtain the geometric parameters of the photovoltaic array, the branch conductor layout of the photovoltaic support and module frame, and the lightning return stroke current parameters; A lightning discharge channel model is established based on the geometry of the lightning discharge channel; On the lightning discharge channel defined by the lightning discharge channel model, the lightning return stroke current is represented by the exponential decay modified transmission line model. The current element on the lightning discharge channel is used as the dipole source. Based on the dipole method, the radiation component of the lightning electromagnetic field is ignored. The time and space are discretized to calculate the incident lightning electromagnetic field at any point in the space near the photovoltaic array. The photovoltaic bracket and module frame are decomposed into multiple independent loops, and an RL equivalent circuit is established for each independent loop. The lightning flux passing through each independent loop is calculated based on the incident lightning electromagnetic field. The induced electromotive force of each independent loop is obtained by differentiating the lightning flux with respect to time. The induced electromotive force is substituted into the RL equivalent circuit as a voltage source to solve for the induced current of each independent loop. Using the induced current on each independent loop conductor as a linear excitation source, the scattered field generated by each conductor at any point in space is calculated. The scattered fields generated by all conductors are vector superimposed to obtain the scattered field generated by the multi-branch conductor structure of the photovoltaic array. The incident electromagnetic field and the scattered field are vector-superimposed to obtain the total spatial magnetic field; The magnetic flux of the total spatial magnetic field passing through the DC cable loop of the photovoltaic array is calculated, and the lightning-induced overvoltage of the DC loop of the photovoltaic array is calculated based on the magnetic flux.
[0007] Secondly, the present invention provides a lightning-induced overvoltage analysis system for photovoltaic arrays, comprising: The acquisition module is configured to acquire the geometric structural parameters of the photovoltaic array, the branch conductor layout of the photovoltaic support and module frame, and the lightning return stroke current parameters. The module is configured to build a lightning discharge channel model based on the geometry of the lightning discharge channel; The calculation module is configured to use an exponentially decaying modified transmission line model to represent the lightning return stroke current on the lightning discharge channel defined by the lightning discharge channel model, take the current element on the lightning discharge channel as a dipole source, ignore the radiation component of the lightning electromagnetic field based on the dipole method, discretize the time and space, and calculate the incident lightning electromagnetic field at any point in the space near the photovoltaic array. The solution module is configured to decompose the photovoltaic bracket and module frame into multiple independent loops, establish the RL equivalent circuit of each independent loop, calculate the lightning flux passing through each independent loop based on the incident lightning electromagnetic field, obtain the induced electromotive force of each independent loop by differentiating the lightning flux with respect to time, and substitute the induced electromotive force as a voltage source into the RL equivalent circuit to solve for the induced current of each independent loop. The first superposition module is configured to use the induced current on each independent loop conductor as a linear excitation source to calculate the scattered field generated by each conductor at any point in space, and to perform vector superposition of the scattered fields generated by all conductors to obtain the scattered field generated by the multi-branch conductor structure of the photovoltaic array. The second superposition module is configured to vector superimpose the incident electromagnetic field and the scattered field to obtain the total spatial magnetic field. The module is configured to calculate the magnetic flux of the total spatial magnetic field passing through the DC cable loop of the photovoltaic array, and to calculate the lightning-induced overvoltage of the DC loop of the photovoltaic array based on the magnetic flux.
[0008] Thirdly, an electronic device is provided, comprising: at least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the steps of the lightning-induced overvoltage analysis method for a photovoltaic array according to any embodiment of the present invention.
[0009] Fourthly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the program instructions are executed by a processor, the processor performs the steps of the lightning-induced overvoltage analysis method for photovoltaic arrays according to any embodiment of the present invention.
[0010] The lightning-induced overvoltage analysis method and system for photovoltaic arrays proposed in this application fully consider the influence of multi-branch conductors of the photovoltaic array on the spatial electromagnetic field, thereby improving the calculation accuracy of the lightning-induced voltage of the photovoltaic array. The "field-line" coupling model can avoid the huge computational load of conventional electromagnetic transient calculation methods on the metal conductor mesh, significantly reducing the calculation time, and is suitable for rapid evaluation of lightning-induced overvoltage of large-scale photovoltaic arrays. Attached Figure Description
[0011] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0012] Figure 1 A flowchart of a lightning-induced overvoltage analysis method for photovoltaic arrays provided in an embodiment of the present invention; Figure 2 This is a structural block diagram of a lightning strike induced overvoltage analysis system for a photovoltaic array, provided in one embodiment of the present invention. Figure 3This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation
[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0014] Please see Figure 1 The diagram shows a flowchart of a lightning-induced overvoltage analysis method for photovoltaic arrays according to this application.
[0015] like Figure 1 As shown, the method for analyzing lightning-induced overvoltage in photovoltaic arrays specifically includes the following steps: Step S101: Obtain the geometric structure parameters of the photovoltaic array, the branch conductor layout of the photovoltaic support and module frame, and the lightning return stroke current parameters.
[0016] In this step, the geometric parameters of the photovoltaic array include the size, tilt angle, and array arrangement of the photovoltaic modules. The branch conductor layout of the photovoltaic support structure and module frame includes the spatial position, length, and connection relationship of each branch conductor of the photovoltaic support structure, as well as the size and shape of the module frame. Lightning return current parameters include the lightning current amplitude, return velocity, and current decay constant.
[0017] Step S102: Establish a lightning discharge channel model based on the geometry of the lightning discharge channel.
[0018] In this step, the lightning discharge channel is equivalent to a straight channel perpendicular to the ground. A cylindrical coordinate system is established, with the plane where the photovoltaic array is located as the Oxy plane and the direction perpendicular to the plane where the photovoltaic array is located as the z-axis direction. The return stroke height of the lightning discharge channel is determined, and the return stroke height varies with time, expressed as: , In the formula, Let be the return stroke height of the lightning current at time t. The return stroke velocity of the lightning current. The speed at which electromagnetic waves propagate in a vacuum. Let be the axial coordinates of the field point in the cylindrical coordinate system. Lightning current element Arrival Point distance, The radial coordinates of the field point in the cylindrical coordinate system; A lightning discharge channel model is established based on the return stroke height, the return stroke velocity, and the spatial position of the straight channel.
[0019] Step S103: On the lightning discharge channel defined by the lightning discharge channel model, the lightning return stroke current is represented by the exponential decay modified transmission line model. The current element on the lightning discharge channel is used as the dipole source. Based on the dipole method, the radiation component of the lightning electromagnetic field is ignored. The time and space are discretized to calculate the incident lightning electromagnetic field at any point in the space near the photovoltaic array.
[0020] In this step, the lightning return stroke current is represented by an exponentially decaying modified transmission line model on the lightning discharge channel defined by the lightning discharge channel model, and the expression is: , In the formula, The lightning current is distributed along the lightning discharge channel. Lightning current element height, Let be the current decay constant. The return stroke velocity of the lightning current. For the bottom of the lightning discharge channel at a certain time Lightning current; The lightning discharge channel is discretized along the height direction into multiple current elements. Each current element is used as a dipole source. Based on the dipole method, the radiation component of the lightning electromagnetic field is ignored. The time and space are discretized to calculate the incident lightning electromagnetic field at any point in space near the photovoltaic array at time t. The expression is: , In the formula, As a venue The incident electromagnetic field of the lightning at time t, Let be the radial coordinates of the field point in the cylindrical coordinate system. Let be the axial coordinates of the field point in the cylindrical coordinate system. Let be the unit direction vector of the tangential coordinate axis in cylindrical coordinates. Let be the return stroke height of the lightning current at time t. Lightning current element Arrival Point distance, Lightning current element During the delay time The lightning current below, The speed at which electromagnetic waves propagate in a vacuum. is the angular constant of a spherical solid.
[0021] Step S104: Decompose the photovoltaic bracket and module frame into multiple independent loops, establish the RL equivalent circuit for each independent loop, calculate the lightning flux passing through each independent loop based on the incident lightning electromagnetic field, obtain the induced electromotive force of each independent loop by differentiating the lightning flux with respect to time, substitute the induced electromotive force as a voltage source into the RL equivalent circuit, and solve for the induced current of each independent loop.
[0022] In this step, the photovoltaic module frame is formed into a separate frame loop, and the photovoltaic support is divided into a first loop, a second loop, a third loop, a fourth loop, and a fifth loop. The first loop includes branches a, i, f, e, d, k, g, and j; the second loop includes branches a, i, b, and j; the third loop includes branches b, f, c, and g; the fourth loop includes branches c, e, d, and k; and the fifth loop includes branches a, i, f, c, g, and j. For each independent loop among the boundary loop, the first loop, the second loop, the third loop, the fourth loop, and the fifth loop, the mathematical expression of the independent loop is determined by the normal vector of the plane containing the independent loop and any point on the independent loop: , In the formula, For the independent loop, point on the Oxy plane The corresponding z-coordinate at that location Points on an independent loop z-coordinate Let x be the x-direction component of the normal vector of the plane containing the independent loop. Let y be the y-direction component of the normal vector of the plane containing the independent loop. Let z be the z-direction component of the normal vector of the plane containing the independent loop. Points on an independent loop x-coordinate, Points on an independent loop The y-coordinate, The x-coordinate on the Oxy plane. The coordinates in the y-direction on the Oxy plane; The lightning flux passing through the independent loop is determined by the following expression: , In the formula, For the lightning flux passing through the independent loop, The magnetic permeability of the medium through which the electromagnetic field of lightning propagates in space. The tilt angle of the photovoltaic array. Let be the angular constant of the spherical solid, and z be the z-direction coordinate on the plane of the independent loop. For lightning current, The speed at which electromagnetic waves propagate in a vacuum. and This represents the y-direction projection boundary of an independent loop in the Oxy plane. These are integral infinitesimal elements in the z, x, and y directions, respectively. By differentiating the lightning flux through the photovoltaic array circuit with respect to time, the induced electromotive force generated by the lightning incident field in the circuit is determined. Establish the RL equivalent circuit for each independent loop. The mathematical model of the RL equivalent circuit is as follows: , , In the formula, The equivalent inductance of the independent circuit is... This refers to the induced current in an independent circuit. Let be the derivative of the induced current with respect to time in an independent circuit. The equivalent resistance of an independent circuit. This refers to the induced electromotive force in an independent circuit. The permeability of free space, The loop length of an independent loop. The conductivity of an independent loop conductor; The C-shaped conductor of the frame support is equivalent to a cylindrical conductor. The expression for the equivalent radius of the cylindrical conductor is: , In the formula, The equivalent radius of a C-type conductor when it is equivalent to a cylindrical conductor. The thickness of the C-type conductor. The width of the C-type conductor. The length of the C-type conductor, Pi; The expression for calculating the induced current on the branch conductors of the photovoltaic support is: , In the formula, For the inductor matrix of the support branch, Let be the induced current in branch a. Let be the induced current in branch b. Let be the induced current in branch c. Let be the induced current in branch d. The induced current in branch e, Let f be the induced current in branch f. For the resistance matrix of the support branch, This represents the induced electromotive force of the first circuit. This is the induced electromotive force of the second circuit. This is the induced electromotive force of the third circuit. This is the induced electromotive force of the fourth circuit. This is the induced electromotive force of the fifth circuit.
[0023] Step S105: Using the induced current on each independent loop conductor as a linear excitation source, calculate the scattered field generated by each conductor at any point in space, and perform vector superposition of the scattered fields generated by all conductors to obtain the scattered field generated by the multi-branch conductor structure of the photovoltaic array.
[0024] In this step, a cylindrical coordinate system is established with each branch conductor of the photovoltaic array as the Z-axis and the center of the conductor as the origin; Using the induced current in the conductor as the excitation source, the scattered field caused by the conductor in space is solved, and the expression is: , In the formula, For the k-th conductor at the field point The scattered field generated at time t Let be the radial coordinates of the field point in the cylindrical coordinate system. Let be the axial coordinates of the field point in the cylindrical coordinate system. Let be the unit direction vector of the tangential coordinate axis in cylindrical coordinates. Let k be the length of the k-th conductor. For the current element on the k-th conductor During the delay time The induced current under, Let the height of the current element on the k-th conductor be . For the current element on the k-th conductor to the field point distance, The speed at which electromagnetic waves propagate in a vacuum. Let the current element be the k-th conductor. It is the angular constant of a spherical solid; The scattered fields generated by the branch conductors of all the frame supports are vector superimposed to obtain the scattered field generated by the multi-conductor structure of the photovoltaic array.
[0025] Step S106: The incident electromagnetic field and the scattered field are vector superimposed to obtain the total spatial magnetic field.
[0026] Step S107: Calculate the magnetic flux of the total spatial magnetic field passing through the DC cable loop of the photovoltaic array, and calculate the lightning-induced overvoltage of the DC loop of the photovoltaic array based on the magnetic flux.
[0027] In this step, the total magnetic field in space is double-integrated over the area enclosed by the DC cable loop of the photovoltaic array to obtain the magnetic flux passing through the DC cable loop of the photovoltaic array, expressed as: , In the formula, The magnetic flux passing through the DC cable loop of the photovoltaic array. The area enclosed by the DC cable loops of the photovoltaic array. Indicates the area A double integral over an area, where the object of integration is an area. The entire area of the micro-element, The total magnetic field in space, It is an area differential element vector. The direction is the normal direction of the area enclosed by the DC cable loops of the photovoltaic array. Represents the total magnetic field in space In the area integral differential element vector Components in direction and differential vectors of area The product; Differentiating the magnetic flux passing through the DC cable loop of the photovoltaic array with respect to time and taking the negative value yields the lightning-induced overvoltage of the DC loop of the photovoltaic array, expressed as: , In the formula, This refers to the lightning-induced overvoltage in the DC circuit of the photovoltaic array. The sign indicates that the time derivative is taken, and the negative sign indicates that the direction of the lightning-induced overvoltage conforms to Lenz's law.
[0028] In summary, the method of this application obtains the geometric parameters of the photovoltaic array, the layout of the branch conductors, and the parameters of the lightning return stroke current; establishes a lightning discharge channel model; uses an exponentially decaying modified transmission line model to represent the lightning return stroke current, and calculates the incident lightning electromagnetic field based on the dipole method; decomposes the photovoltaic support and module frame into multiple independent loops, establishes an RL equivalent circuit, and solves for the induced current in each loop; calculates the scattered field using the induced current as the excitation source, and obtains the total spatial magnetic field by vector superposition with the incident lightning electromagnetic field; calculates the magnetic flux of the total spatial magnetic field through the DC cable loop to obtain the lightning-induced overvoltage; fully considers the electromagnetic transient coupling effect of multiple branch conductors, improves the calculation accuracy, and significantly reduces the calculation time, making it suitable for rapid evaluation of large-scale photovoltaic arrays.
[0029] Please see Figure 2 The diagram shows a structural block diagram of a lightning-induced overvoltage analysis system for a photovoltaic array according to this application.
[0030] like Figure 2As shown, the lightning-induced overvoltage analysis system 200 includes an acquisition module 210, a construction module 220, a calculation module 230, a solution module 240, a first superposition module 250, a second superposition module 260, and a determination module 270.
[0031] The acquisition module 210 is configured to acquire the geometric structural parameters of the photovoltaic array, the branch conductor layout of the photovoltaic support and module frame, and the lightning return stroke current parameters; the construction module 220 is configured to establish a lightning discharge channel model based on the geometry of the lightning discharge channel; the calculation module 230 is configured to use an exponentially decaying modified transmission line model to represent the lightning return stroke current on the lightning discharge channel defined by the lightning discharge channel model, using the current element on the lightning discharge channel as a dipole source, ignoring the radiation component of the lightning electromagnetic field based on the dipole method, discretizing the time and space, and calculating the incident lightning electromagnetic field at any point in the space near the photovoltaic array; the solution module 240 is configured to decompose the photovoltaic support and module frame into multiple independent loops, establish the RL equivalent circuit of each independent loop, and calculate the penetration voltage based on the incident lightning electromagnetic field. The lightning electromagnetic flux through each independent loop is used to induced electromotive force (EMF) of each independent loop by differentiating the lightning electromagnetic flux with respect to time. The induced EMF is then substituted into the RL equivalent circuit as a voltage source to solve for the induced current of each independent loop. The first superposition module 250 is configured to use the induced current on the conductor of each independent loop as a linear excitation source to calculate the scattered field generated by each conductor at any point in space. The scattered fields generated by all conductors are vector superimposed to obtain the scattered field generated by the multi-branch conductor structure of the photovoltaic array. The second superposition module 260 is configured to vector superimpose the incident lightning electromagnetic field and the scattered field to obtain the total spatial magnetic field. The determination module 270 is configured to calculate the magnetic flux of the total spatial magnetic field through the DC cable loop of the photovoltaic array and calculate the lightning-induced overvoltage of the DC loop of the photovoltaic array based on the magnetic flux.
[0032] It should be understood that Figure 2 The modules and references described in the document Figure 1 The steps described in the text correspond to those in the method described above. Therefore, the operations, features, and corresponding technical effects described above also apply to the method described in the text. Figure 2 The various modules in the document will not be described in detail here.
[0033] In other embodiments, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the program instructions are executed by a processor, the processor performs the lightning-induced overvoltage analysis method for photovoltaic arrays in any of the above method embodiments. In one embodiment, the computer-readable storage medium of the present invention stores computer-executable instructions, which are configured as follows: Obtain the geometric parameters of the photovoltaic array, the branch conductor layout of the photovoltaic support and module frame, and the lightning return stroke current parameters; A lightning discharge channel model is established based on the geometry of the lightning discharge channel; On the lightning discharge channel defined by the lightning discharge channel model, the lightning return stroke current is represented by the exponential decay modified transmission line model. The current element on the lightning discharge channel is used as the dipole source. Based on the dipole method, the radiation component of the lightning electromagnetic field is ignored. The time and space are discretized to calculate the incident lightning electromagnetic field at any point in the space near the photovoltaic array. The photovoltaic bracket and module frame are decomposed into multiple independent loops, and an RL equivalent circuit is established for each independent loop. The lightning flux passing through each independent loop is calculated based on the incident lightning electromagnetic field. The induced electromotive force of each independent loop is obtained by differentiating the lightning flux with respect to time. The induced electromotive force is substituted into the RL equivalent circuit as a voltage source to solve for the induced current of each independent loop. Using the induced current on each independent loop conductor as a linear excitation source, the scattered field generated by each conductor at any point in space is calculated. The scattered fields generated by all conductors are vector superimposed to obtain the scattered field generated by the multi-branch conductor structure of the photovoltaic array. The incident electromagnetic field and the scattered field are vector-superimposed to obtain the total spatial magnetic field; The magnetic flux of the total spatial magnetic field passing through the DC cable loop of the photovoltaic array is calculated, and the lightning-induced overvoltage of the DC loop of the photovoltaic array is calculated based on the magnetic flux.
[0034] Computer-readable storage media may include a stored program area and a stored data area, wherein the stored program area may store an operating system and an application program required for at least one function; the stored data area may store data created based on the use of the lightning-induced overvoltage analysis system for photovoltaic arrays, etc. Furthermore, the computer-readable storage medium may include high-speed random access memory, and may also include memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, the computer-readable storage medium may optionally include memory remotely configured relative to a processor, which can be connected to the lightning-induced overvoltage analysis system for photovoltaic arrays via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.
[0035] Figure 3 This is a schematic diagram of the structure of the electronic device provided in the embodiment of the present invention, such as... Figure 3As shown, the device includes a processor 310 and a memory 320. The electronic device may also include an input device 330 and an output device 340. The processor 310, memory 320, input device 330, and output device 340 can be connected via a bus or other means. Figure 3 Taking a bus connection as an example, the memory 320 is the computer-readable storage medium described above. The processor 310 executes various server functions and data processing by running non-volatile software programs, instructions, and modules stored in the memory 320, thereby implementing the lightning-induced overvoltage analysis method for photovoltaic arrays described in the above method embodiment. The input device 330 can receive input digital or character information and generate key signal inputs related to user settings and function control of the lightning-induced overvoltage analysis system for photovoltaic arrays. The output device 340 may include a display screen or other display device.
[0036] The aforementioned electronic device can execute the method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in the method provided in the embodiments of the present invention.
[0037] In one implementation, the aforementioned electronic device is applied to the aforementioned lightning-induced overvoltage analysis system for photovoltaic arrays, serving as a client, and includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to: Obtain the geometric parameters of the photovoltaic array, the branch conductor layout of the photovoltaic support and module frame, and the lightning return stroke current parameters; A lightning discharge channel model is established based on the geometry of the lightning discharge channel; On the lightning discharge channel defined by the lightning discharge channel model, the lightning return stroke current is represented by the exponential decay modified transmission line model. The current element on the lightning discharge channel is used as the dipole source. Based on the dipole method, the radiation component of the lightning electromagnetic field is ignored. The time and space are discretized to calculate the incident lightning electromagnetic field at any point in the space near the photovoltaic array. The photovoltaic bracket and module frame are decomposed into multiple independent loops, and an RL equivalent circuit is established for each independent loop. The lightning flux passing through each independent loop is calculated based on the incident lightning electromagnetic field. The induced electromotive force of each independent loop is obtained by differentiating the lightning flux with respect to time. The induced electromotive force is substituted into the RL equivalent circuit as a voltage source to solve for the induced current of each independent loop. Using the induced current on each independent loop conductor as a linear excitation source, the scattered field generated by each conductor at any point in space is calculated. The scattered fields generated by all conductors are vector superimposed to obtain the scattered field generated by the multi-branch conductor structure of the photovoltaic array. The incident electromagnetic field and the scattered field are vector-superimposed to obtain the total spatial magnetic field; The magnetic flux of the total spatial magnetic field passing through the DC cable loop of the photovoltaic array is calculated, and the lightning-induced overvoltage of the DC loop of the photovoltaic array is calculated based on the magnetic flux.
[0038] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of various embodiments or some parts of embodiments.
[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for lightning induced overvoltage analysis of a photovoltaic array, characterized by, include: Obtain the geometric parameters of the photovoltaic array, the branch conductor layout of the photovoltaic support and module frame, and the lightning return stroke current parameters; A lightning discharge channel model is established based on the geometry of the lightning discharge channel; On the lightning discharge channel defined by the lightning discharge channel model, the lightning return stroke current is represented by the exponential decay modified transmission line model. The current element on the lightning discharge channel is used as the dipole source. Based on the dipole method, the radiation component of the lightning electromagnetic field is ignored. The time and space are discretized to calculate the incident lightning electromagnetic field at any point in the space near the photovoltaic array. The photovoltaic bracket and module frame are decomposed into multiple independent loops, and an RL equivalent circuit is established for each independent loop. The lightning flux passing through each independent loop is calculated based on the incident lightning electromagnetic field. The induced electromotive force of each independent loop is obtained by differentiating the lightning flux with respect to time. The induced electromotive force is substituted into the RL equivalent circuit as a voltage source to solve for the induced current of each independent loop. Using the induced current on each independent loop conductor as a linear excitation source, the scattered field generated by each conductor at any point in space is calculated. The scattered fields generated by all conductors are vector superimposed to obtain the scattered field generated by the multi-branch conductor structure of the photovoltaic array. The incident electromagnetic field and the scattered field are vector-superimposed to obtain the total spatial magnetic field; The magnetic flux of the total spatial magnetic field passing through the DC cable loop of the photovoltaic array is calculated, and the lightning-induced overvoltage of the DC loop of the photovoltaic array is calculated based on the magnetic flux.
2. A method for lightning-induced overvoltage analysis of a photovoltaic array according to claim 1, characterized in that, The process of establishing a lightning discharge channel model based on the geometry of the lightning discharge channel includes: The lightning discharge channel is equivalent to a straight channel perpendicular to the ground. A cylindrical coordinate system is established, with the plane where the photovoltaic array is located as the Oxy plane and the direction perpendicular to the plane where the photovoltaic array is located as the z-axis direction. The return stroke height of the lightning discharge channel is determined, and the return stroke height varies with time, expressed as: ， wherein is the return stroke height of the lightning current at time t, is the return stroke velocity of the lightning current, is the propagation velocity of electromagnetic waves in vacuum, is the axial coordinate of the field point in the cylindrical coordinate system, is the distance from the lightning current element to the field point , is the radial coordinate of the field point in the cylindrical coordinate system. A lightning discharge channel model is established based on the return stroke height, the return stroke velocity, and the spatial position of the straight channel.
3. The method for analyzing lightning-induced overvoltage in photovoltaic arrays according to claim 1, characterized in that, In the lightning discharge channel defined by the lightning discharge channel model, the lightning return stroke current is represented by an exponentially decaying modified transmission line model. The current element in the lightning discharge channel is used as a dipole source. Based on the dipole method, the radiation component of the lightning electromagnetic field is ignored. Time and space are discretized to calculate the incident lightning electromagnetic field at any point in space near the photovoltaic array, including: In the lightning discharge channel defined by the lightning discharge channel model, the lightning return stroke current is represented by an exponentially decaying modified transmission line model. The lightning discharge channel is discretized into multiple current elements along the height direction. Each current element is used as a dipole source. Based on the dipole method, the radiation component of the lightning electromagnetic field is ignored. The time and space are discretized to calculate the incident lightning electromagnetic field at any point in the space near the photovoltaic array at time t.
4. The method for analyzing lightning-induced overvoltage in photovoltaic arrays according to claim 1, characterized in that, The process involves decomposing the photovoltaic support and module frame into multiple independent loops, establishing an RL equivalent circuit for each independent loop, calculating the lightning flux passing through each independent loop based on the incident lightning electromagnetic field, obtaining the induced electromotive force (EMF) of each independent loop by differentiating the lightning flux with respect to time, and substituting the induced EMF as a voltage source into the RL equivalent circuit to solve for the induced current in each independent loop. The photovoltaic module frames are arranged into separate frame loops, and the photovoltaic support is divided into a first loop, a second loop, a third loop, a fourth loop, and a fifth loop. The first loop includes branches a, i, f, e, d, k, g, and j; the second loop includes branches a, i, b, and j; the third loop includes branches b, f, c, and g; the fourth loop includes branches c, e, d, and k; and the fifth loop includes branches a, i, f, c, g, and j. For each independent loop among the boundary loop, the first loop, the second loop, the third loop, the fourth loop, and the fifth loop, the mathematical expression of the independent loop is determined by the normal vector of the plane containing the independent loop and any point on the independent loop: ， In the formula, For the independent loop, point on the Oxy plane The corresponding z-coordinate at that location Points on an independent loop z-coordinate Let x be the x-direction component of the normal vector of the plane containing the independent loop. Let y be the y-direction component of the normal vector of the plane containing the independent loop. Let z be the z-direction component of the normal vector of the plane containing the independent loop. Points on an independent loop x-coordinate, Points on an independent loop The y-coordinate, The x-coordinate on the Oxy plane. The coordinates in the y-direction on the Oxy plane; The lightning flux passing through the independent loop is determined by the following expression: ， In the formula, For the lightning flux passing through the independent loop, The magnetic permeability of the medium through which the electromagnetic field of lightning propagates in space. The tilt angle of the photovoltaic array. Let be the angular constant of the spherical solid, and z be the z-direction coordinate on the plane of the independent loop. For lightning current, The speed at which electromagnetic waves propagate in a vacuum. and This represents the y-direction projection boundary of an independent loop in the Oxy plane. These are integral infinitesimal elements in the z, x, and y directions, respectively. By differentiating the lightning flux through the photovoltaic array circuit with respect to time, the induced electromotive force generated by the lightning incident field in the circuit is determined. Establish the RL equivalent circuit for each independent loop. The mathematical model of the RL equivalent circuit is as follows: ， ， In the formula, The equivalent inductance of the independent circuit is... This refers to the induced current in an independent circuit. Let be the derivative of the induced current with respect to time in an independent circuit. The equivalent resistance of an independent circuit. This refers to the induced electromotive force in an independent circuit. The permeability of free space, The loop length of an independent loop. The conductivity of an independent loop conductor; The C-shaped conductor of the frame support is equivalent to a cylindrical conductor. The expression for the equivalent radius of the cylindrical conductor is: ， In the formula, The equivalent radius of a C-type conductor when it is equivalent to a cylindrical conductor. The thickness of the C-type conductor. The width of the C-type conductor. The length of the C-type conductor, Pi; The expression for calculating the induced current on the branch conductors of the photovoltaic support is: ， In the formula, For the inductor matrix of the support branch, Let be the induced current in branch a. Let be the induced current in branch b. Let be the induced current in branch c. Let be the induced current in branch d. The induced current in branch e, Let f be the induced current in branch f. For the resistance matrix of the support branch, This represents the induced electromotive force of the first circuit. This is the induced electromotive force of the second circuit. This is the induced electromotive force of the third circuit. This is the induced electromotive force of the fourth circuit. This is the induced electromotive force of the fifth circuit.
5. The method for analyzing lightning-induced overvoltage in photovoltaic arrays according to claim 1, characterized in that, The method involves using the induced current on each independent loop conductor as a linear excitation source to calculate the scattered field generated by each conductor at any point in space. The scattered fields generated by all conductors are then vector-superimposed to obtain the scattered field generated by the multi-branch conductor structure of the photovoltaic array, which includes: A cylindrical coordinate system is established with each branch conductor of the photovoltaic array as the Z-axis and the center of the conductor as the origin. Using the induced current in the conductor as the excitation source, the scattered field caused by the conductor in space is solved, and the expression is: ， In the formula, For the k-th conductor at the field point The scattered field generated at time t Let be the radial coordinates of the field point in the cylindrical coordinate system. Let be the axial coordinates of the field point in the cylindrical coordinate system. Let be the unit direction vector of the tangential coordinate axis in cylindrical coordinates. Let k be the length of the k-th conductor. For the current element on the k-th conductor During the delay time The induced current under, Let the height of the current element on the k-th conductor be . For the current element on the k-th conductor to the field point distance, The speed at which electromagnetic waves propagate in a vacuum. Let the current element be the k-th conductor. It is the angular constant of a spherical solid; The scattered fields generated by the branch conductors of all the frame supports are vector superimposed to obtain the scattered field generated by the multi-conductor structure of the photovoltaic array.
6. The method for analyzing lightning-induced overvoltage in photovoltaic arrays according to claim 1, characterized in that, The calculation of the magnetic flux of the total spatial magnetic field passing through the DC cable loop of the photovoltaic array, and the calculation of the lightning-induced overvoltage of the DC loop of the photovoltaic array based on the magnetic flux, include: By performing a double integral over the area enclosed by the DC cable loop of the photovoltaic array, the magnetic flux passing through the DC cable loop of the photovoltaic array is obtained, and its expression is: ， In the formula, The magnetic flux passing through the DC cable loop of the photovoltaic array. The area enclosed by the DC cable loops of the photovoltaic array. Indicates the area A double integral over an area, where the object of integration is an area. The entire area of the micro-element, The total magnetic field in space, It is an area differential element vector. The direction is the normal direction of the area enclosed by the DC cable loops of the photovoltaic array. Represents the total magnetic field in space In the area integral differential element vector Components in direction and differential vectors of area The product; Differentiating the magnetic flux passing through the DC cable loop of the photovoltaic array with respect to time and taking the negative value yields the lightning-induced overvoltage of the DC loop of the photovoltaic array, expressed as: ， In the formula, This refers to the lightning-induced overvoltage in the DC circuit of the photovoltaic array. The sign indicates that the time derivative is taken, and the negative sign indicates that the direction of the lightning-induced overvoltage conforms to Lenz's law.
7. A lightning-induced overvoltage analysis system for photovoltaic arrays, characterized in that, include: The acquisition module is configured to acquire the geometric structural parameters of the photovoltaic array, the branch conductor layout of the photovoltaic support and module frame, and the lightning return stroke current parameters. The module is configured to build a lightning discharge channel model based on the geometry of the lightning discharge channel; The calculation module is configured to use an exponentially decaying modified transmission line model to represent the lightning return stroke current on the lightning discharge channel defined by the lightning discharge channel model, take the current element on the lightning discharge channel as a dipole source, ignore the radiation component of the lightning electromagnetic field based on the dipole method, discretize the time and space, and calculate the incident lightning electromagnetic field at any point in the space near the photovoltaic array. The solution module is configured to decompose the photovoltaic bracket and module frame into multiple independent loops, establish the RL equivalent circuit of each independent loop, calculate the lightning flux passing through each independent loop based on the incident lightning electromagnetic field, obtain the induced electromotive force of each independent loop by differentiating the lightning flux with respect to time, and substitute the induced electromotive force as a voltage source into the RL equivalent circuit to solve for the induced current of each independent loop. The first superposition module is configured to use the induced current on each independent loop conductor as a linear excitation source to calculate the scattered field generated by each conductor at any point in space, and to perform vector superposition of the scattered fields generated by all conductors to obtain the scattered field generated by the multi-branch conductor structure of the photovoltaic array. The second superposition module is configured to vector superimpose the incident electromagnetic field and the scattered field to obtain the total spatial magnetic field. The module is configured to calculate the magnetic flux of the total spatial magnetic field passing through the DC cable loop of the photovoltaic array, and to calculate the lightning-induced overvoltage of the DC loop of the photovoltaic array based on the magnetic flux.
8. An electronic device, characterized in that, include: At least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 6.
9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, it implements the method described in any one of claims 1 to 6.