Simulation model, method, equipment and medium of photovoltaic array grounding system

Abstract

The invention provides a simulation model, method and device of a photovoltaic array grounding system and a medium. The simulation model comprises a photovoltaic support model, a cable model, a surge protection device model and a simulation calculation module. The photovoltaic support model is provided with a plurality of photovoltaic assembly models which are connected with a ground screen through a grounding down lead. Simulation cables in the cable model form a closed loop, and the closed loop is connected to a simulation combiner box and a simulation inverter through cables; two analog surge protection devices of the surge protection device model are respectively located at an analog combiner box and an analog inverter, and grounding shunting is carried out when a potential difference is detected to exceed a preset action threshold value; when lightning current is injected into the photovoltaic module models, the simulation calculation module calculates the potential difference between the photovoltaic support model and the simulation cable along the line, and calculates the current and potential distribution of each photovoltaic module model during lightning stroke. The simulation model can accurately predict the condition of the system so as to provide technical support for dynamic adjustment of the system.

Description

Technical Field

[0001] The present invention belongs to the technical field of high voltage protection of photovoltaic arrays, and in particular relates to a simulation model, method, equipment and medium of a photovoltaic array grounding system. Background Art

[0002] Photovoltaic arrays efficiently utilize solar energy and convert it into electricity to meet daily and industrial electricity needs. At present, the commonly used lightning protection measures are to use the metal frame of the solar panel as a lightning rod, connect the aluminum alloy frame around the solar panel to the bracket, and ground it through equipotential connection. When a direct lightning strike occurs, if the lightning energy is quickly discharged into the ground through the aluminum frame, the solar panel can be protected from direct lightning damage. However, the wiring of the photovoltaic array is complex, with many branches, long distances, and a large area. Due to the small capacity of the photovoltaic power generation system, lightning protection and grounding technology has not received enough attention. However, with the continuous expansion of the scale and area of ​​​​the photovoltaic power station, lightning poses a major threat to its safe operation. When lightning directly hits the solar panel, it will cause serious damage to the photovoltaic equipment and even cause the system to fail. Therefore, the grounding and lightning protection technology of the photovoltaic power station has become a key factor in its reliable and safe operation.

[0003] As an improvement, in order to study the impact of lightning strikes on photovoltaic power stations, it is necessary to build a corresponding simulation analysis model. Although electromagnetic field simulation software can construct an electromagnetic field model of a three-dimensional grounding system network, due to the high complexity of the electromagnetic field model of the photovoltaic power station, the amount of calculation is too large when performing lightning protection grounding calculations, making it difficult to carry out effective and accurate simulation research. When calculating the lightning protection grounding of a photovoltaic power station, it is necessary to fully consider the electrical connection status of photovoltaic brackets, photovoltaic panels, cables, etc. under lightning strikes, as well as the response of surge protection devices in each part. It is crucial to maintain coordination and connectivity between all components to ensure that the simulation results can truly reflect the actual situation of the photovoltaic power station after lightning strikes, and provide a reliable reference for subsequent lightning protection grounding design. In the prior art, the photovoltaic module model is usually greatly simplified, and only a simple photovoltaic bracket structure is constructed for calculation and analysis. The potential distribution near the photovoltaic panel cannot be calculated, and the phenomenon of direct burial of cables through pipes and the discharge breakdown and surge protection device action that may be caused by lightning strikes are not considered. Therefore, in summary, the existing simulation model of the photovoltaic array is too simplified and cannot accurately calculate the potential distribution near the photovoltaic panel; in addition, the existing model does not fully consider the insulation breakdown phenomenon that may occur after a lightning strike and the response of the surge protection device, resulting in a large deviation between the simulation results and the actual operating status. Summary of the invention

[0004] The present invention provides a simulation model, method, device and medium for a photovoltaic array grounding system, aiming to solve the problem that the existing photovoltaic array simulation model is too simplified and cannot accurately calculate the potential distribution near the photovoltaic panel; the existing model does not fully consider the insulation breakdown phenomenon that may occur after a lightning strike and the response of the surge protection device, resulting in a large deviation between the simulation result and the actual operating state.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] The present invention provides a simulation model of a photovoltaic array grounding system, the simulation model comprising a photovoltaic support model, a cable model, a surge protection device model and a simulation calculation module; wherein:

[0007] The photovoltaic support model includes columns, inclined beams and cross beams; several photovoltaic module models are simulated and set in the photovoltaic support model, and the photovoltaic support model is connected to the ground grid through the grounding lead;

[0008] In the cable model, the simulated cable passes through the crossbeam of the photovoltaic support model to form a closed loop; the closed loop extends to the outside of the photovoltaic support model through the cable and is connected to the simulated junction box and the simulated inverter;

[0009] The surge protection device model includes two simulated surge protection devices, which are respectively located at the simulated combiner box and the simulated inverter. The surge protection device model is used to perform grounding shunt when it is detected that the potential difference exceeds a preset action threshold.

[0010] The simulation calculation module is used to calculate the potential difference between the photovoltaic bracket model and the simulated cable along the line when a lightning current is injected into a photovoltaic module model, and simulate the discharge breakdown phenomenon and the action of the surge protection device model, and calculate the current and potential distribution of each photovoltaic module model in the simulation model when struck by lightning.

[0011] In some embodiments, in the cable model, the photovoltaic panel is regarded as an equipotential metal plate, and the potential of the photovoltaic panel is represented by the loop potential formed by simulating the cable around the photovoltaic support model along the line.

[0012] In some embodiments, a surge protection device action judgment module is also included. The surge protection device action judgment module is used to calculate the potential difference between the simulated surge protection device and the nearby cables at the simulated junction box and the simulated inverter. When the potential difference exceeds the action threshold of the simulated surge protection device, the simulated surge protection device performs grounding shunting through an added conductor.

[0013] In some embodiments, a simulation result display module is further included, and the simulation result display module is used to display the current and potential distribution of each photovoltaic component model in the simulation model when struck by lightning and the action status of the surge protection device model.

[0014] In some embodiments, in the photovoltaic support model, the crossbeam is modeled as round steel, and the columns are modeled as short columns and long columns. The dimensions of the columns, inclined beams and crossbeams in the photovoltaic support model are equivalently simulated and set based on the physical model.

[0015] In some embodiments, the simulation model is constructed based on electromagnetic field simulation software.

[0016] In some implementations, in the simulation calculation module, the moment method is used to calculate the distribution of current and potential of each photovoltaic module model in the simulation model when struck by lightning.

[0017] The present invention also provides a simulation method for a photovoltaic array grounding system, comprising the following steps:

[0018] S1. Based on the simulation model, inject lightning current into a photovoltaic module model;

[0019] S2, the simulation calculation module calculates the potential difference between the photovoltaic support model and the simulated cables along the line, finds the potential breakdown point and simulates the breakdown phenomenon;

[0020] S3, the simulation calculation module calculates the potential difference between the simulated surge protection device at the simulated combiner box and the simulated inverter and the nearby simulated cable to determine whether the simulated surge protection device is actuated;

[0021] S4. Output simulation results, including the current and potential distribution of each component of the photovoltaic array and the action results of the simulated surge protection device.

[0022] The present invention also provides a computer device, comprising a memory, a processor and a computer program stored and running on the memory, and the processor implements the steps of the simulation method of the photovoltaic array grounding system when executing the computer program.

[0023] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the simulation method for a photovoltaic array grounding system are implemented.

[0024] Compared with the prior art, the simulation model, method, device and medium of a photovoltaic array grounding system of the present invention have the following beneficial effects:

[0025] The present invention provides a simulation model of a photovoltaic array grounding system, the simulation model comprises a photovoltaic support model, a cable model, a surge protection device model and a simulation calculation module; wherein: the photovoltaic support model comprises a column, an inclined beam and a cross beam; a plurality of photovoltaic component models are simulated and set in the photovoltaic support model, and the photovoltaic support model is connected to a ground grid through a grounding down conductor; in the cable model, a simulated cable passes through the cross beam of the photovoltaic support model to form a closed loop, the closed loop is extended to the outside of the photovoltaic support model through the cable, and is connected to a simulated junction box and a simulated inverter; the surge protection device model comprises two simulated surge protection devices, the two simulated surge protection devices are respectively located at the positions of the simulated junction box and the simulated inverter, and the surge protection device model is used for grounding shunting when it is detected that the potential difference exceeds a preset action threshold; the simulation calculation module is used for calculating the potential difference between the photovoltaic support model and the simulated cable along the line when a lightning current is injected into a photovoltaic component model, simulating the discharge breakdown phenomenon and the action of the surge protection device model, and calculating the distribution of the current and potential of each photovoltaic component model in the simulation model when struck by lightning. Based on the above content, the present invention introduces a method of surrounding the photovoltaic bracket model with simulated cables along the line, and the potential distribution near the photovoltaic panel can be obtained by using the potential results on the simulated cable. The present invention merges the buried steel pipe with the photovoltaic bracket model to jointly assume the diversion function, and at the same time separates the steel pipe from the simulated cable core. An insulating layer is added to the simulated cable core and laid parallel to the steel pipe, thereby solving the problem that the cable cannot be directly buried in the pipe. When the potential difference between the photovoltaic bracket model and the simulated cable along the line exceeds the withstand voltage value of the equipment, a discharge breakdown phenomenon will occur, resulting in lightning current transmission. In addition, if it is detected that the potential difference between the simulated junction box or the simulated inverter and the simulated cable exceeds the action threshold of the simulated surge protection device, the surge protection device will immediately act to ground. The present invention takes into account the multi-level protection of the photovoltaic power station, not only considering the conduction between the photovoltaic bracket and the cable, but also calculating the potential difference between the simulated junction point and the simulated inverter to the nearby photovoltaic component model, and judging whether the surge protection device is actuated. By dynamically adjusting the simulation model of the photovoltaic array grounding system, it can be more in line with the actual situation, improve the accuracy of the simulation model and the accuracy of the calculation results, and thus is expected to reduce equipment damage caused by lightning strikes and reduce subsequent maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0027] Figure 1 A schematic diagram of a simulation model, method, device and medium of a photovoltaic array grounding system of the present invention;

[0028] Figure 2 A side view schematic diagram of a simulation model, method, device and medium of a photovoltaic array grounding system of the present invention;

[0029] Figure 3 A schematic diagram of the overall arrangement of a simulation model, method, device and photovoltaic component model in a medium of a photovoltaic array grounding system according to the present invention;

[0030] Figure 4 A schematic diagram of a simulation model, method, device and a single photovoltaic module model in a medium of a photovoltaic array grounding system of the present invention;

[0031] Figure 5 A schematic diagram of a breakdown condition of a photovoltaic bracket in a simulation model, method, device and medium of a photovoltaic bracket model of a photovoltaic array grounding system of the present invention;

[0032] Figure 6 A schematic diagram of a simulation model, method, device and simulated surge protection device at a simulated confluence point in a medium of a photovoltaic array grounding system according to the present invention;

[0033] Figure 7 The present invention is a schematic diagram of a simulation model, method, device and a simulated surge protection device at a simulated inverter in a simulation model of a photovoltaic array grounding system. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0037] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0038] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0039] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] How to solve the problem of difficulty in calculating the potential near photovoltaic panels in the simulation construction of photovoltaic array grounding systems, and how to solve the problem of inability to build direct buried cables through pipes, thereby improving the accuracy and reliability of simulation calculation and analysis of photovoltaic array grounding systems.

[0041] like Figure 1 and Figure 2 As shown, the present invention provides a simulation model of a photovoltaic array grounding system, the simulation model includes a photovoltaic support model, a cable model, a surge protection device model and a simulation calculation module; wherein:

[0042] The photovoltaic support model includes columns, inclined beams and cross beams; several photovoltaic module models are simulated and set in the photovoltaic support model, and the photovoltaic support model is connected to the ground grid through the grounding lead;

[0043] In the cable model, the simulated cable passes through the crossbeam of the photovoltaic support model to form a closed loop; the closed loop extends to the outside of the photovoltaic support model through the cable and is connected to the simulated junction box and the simulated inverter;

[0044] The surge protection device model includes two simulated surge protection devices, which are respectively located at the simulated combiner box and the simulated inverter. The surge protection device model is used to perform grounding shunt when it is detected that the potential difference exceeds a preset action threshold.

[0045] The simulation calculation module is used to calculate the potential difference between the photovoltaic bracket model and the simulated cable along the line when a lightning current is injected into a photovoltaic module model, and simulate the discharge breakdown phenomenon and the action of the surge protection device model, and calculate the current and potential distribution of each photovoltaic module model in the simulation model when struck by lightning.

[0046] Since the existing photovoltaic module model is greatly simplified, only a simple photovoltaic bracket structure is constructed for calculation and analysis, and the potential distribution near the photovoltaic panel cannot be calculated, and the phenomenon of direct burial of cables through pipes and the possible discharge breakdown after lightning strikes and the action of surge protection devices are not considered. Based on the above problems, the present invention designs a simulation model by constructing models of key components such as photovoltaic brackets, cables, and surge protection devices, and uses a simulation calculation module to simulate the electrical behavior of the photovoltaic array under lightning strikes. The photovoltaic bracket model simulates the layout of the columns, inclined beams, cross beams and photovoltaic modules in detail, the cable model simulates the path and closed loop of the cable in the photovoltaic bracket, and the surge protection device model is used to simulate the grounding shunt when the potential difference exceeds the preset threshold. Through the simulation model of the present invention, the electrical behavior of the photovoltaic array during lightning strikes can be predicted before actual installation, and potential risk points can be identified. Based on the simulation results, the grounding system, cable layout, and configuration of the surge protection device of the photovoltaic array can be optimized to improve the safety and reliability of the system.

[0047] In actual working conditions, photovoltaic panels are an important part of photovoltaic modules, responsible for converting solar energy into electrical energy. They are usually made of multiple layers of materials, with solar cells sandwiched between two layers of tempered glass. The tempered glass is an insulator, and the surrounding aluminum alloy frame is a conductor. This complex structure makes it relatively difficult to accurately model it in electromagnetic field simulation software. Considering that the existing model only builds a simple photovoltaic bracket, it is impossible to effectively calculate the potential at the photovoltaic panel.

[0048] Cables are usually buried directly in the soil through pipes, connecting photovoltaic panels in series and connecting each photovoltaic module in parallel to a junction box, ultimately delivering electricity to the inverter. However, it is difficult to accurately simulate the phenomenon of cables being buried directly in pipes during the modeling process. There is a certain gap between the cable core and the buried steel pipe, which makes it impossible to simply regard it as a single conductor with a coating, which increases the complexity of model construction.

[0049] When a photovoltaic bracket is struck by lightning, the electrical connection status between the photovoltaic bracket, cable and photovoltaic panel is crucial. Discharge breakdown may occur between the photovoltaic bracket and the cable due to excessive potential difference, and the lightning current is therefore transmitted to the remote end through the cable. In addition, the surge protection device (SPD) at the junction box and inverter may also be activated due to excessive potential difference, and grounding shunt is performed to achieve protection. Therefore, when simulating and modeling the photovoltaic array grounding system, it is necessary to consider the possible breakdown phenomenon after lightning strike and the action of the surge protection device, so as to better fit the actual operating status of the photovoltaic power station.

[0050] The photovoltaic array of the present invention is composed of a plurality of photovoltaic components, including photovoltaic brackets, cables, junction boxes, inverters, surge protection devices and ground grids. The present invention makes the simulation model closer to the actual photovoltaic bracket structure through equivalent simulation, thereby improving the accuracy of the simulation results.

[0051] like Figure 5 As shown, when the photovoltaic bracket and the cables along the line are broken down due to the potential difference exceeding the withstand voltage value, the present invention adds a conductor at the breakdown point to make the two conductive, so that the lightning current can be transmitted to the far end through the cable. When the potential difference between the SPD and the cable exceeds its action value, the SPD will act to ground, and a conductor will be drawn out from the cable to connect to the SPD, and the lightning current can be dispersed into the ground here.

[0052] In the simulation model of the photovoltaic array grounding system of the present invention, in the circuit simulation, each photovoltaic panel is simulated as a DC voltage source, which is connected in series through cables to send out a sufficiently high voltage. Since the DC voltage source is equivalent to a short circuit under AC, these photovoltaic panels actually form a path under transient conditions, and can be regarded as metal plates with equal potential due to the extremely small potential difference during lightning strikes. When constructing the electromagnetic field simulation model of the photovoltaic array, in order to obtain the potential at the photovoltaic panel, the cable is guided along the channel steel led by the photovoltaic bracket to form a loop, and the potential of the metal plate is close to that of the cable. Cable ( Figure 2 The steel pipe (on the right side in the figure) is usually buried directly in the ground through a pipe. It cannot be simply regarded as a conductor plus coating construction method in the electromagnetic field simulation software. Since the steel pipe plays the same role of conducting current in the circuit as the photovoltaic bracket, it can be modeled as a part of the photovoltaic bracket. There is no electrical connection between the core wire of the cable and the steel pipe, so an insulating coating is provided on the outside of the core wire and placed parallel to the steel pipe. During the modeling process, the cable is wrapped around the photovoltaic bracket channel steel, while ensuring that the distance between the cable and the steel pipe is about one centimeter, so as to more accurately simulate the actual situation. The present invention simplifies the calculation process of the potential of the photovoltaic panel and improves the efficiency of the simulation through the assumption of equipotential.

[0053] The present invention uses the moment method to perform calculations during simulation calculations. The moment method divides the grounding grid into small units, firstly calculates the mutual impedance coefficient and the self-impedance coefficient between the small units, and obtains the following equation based on the assumption of the total leakage current:

[0054]

[0055] According to the boundary condition (2), the electrode potential (i.e., ground potential rise) is have to:

[0056]

[0057] Therefore, the (n+1)-order simultaneous equation system composed of equations (1) and (3) is:

[0058]

[0059] The simplified form is

[0060]

[0061] Among them, [1] is the column vector of unit leakage current; [R] is the resistance coefficient matrix. Assuming that the total leakage current of the ground grid is a known value, the total leakage current is the sum of the leakage currents of each unit, and then the leakage current of each unit and the potential rise of the ground grid can be solved from the matrix.

[0062] like Figure 6 and Figure 7 As shown, the present invention can obtain the potential difference between the photovoltaic bracket and the cables along the line through numerical calculation and simulation analysis, so as to find potential weak points and simulate possible breakdown phenomena. When the photovoltaic bracket and the cable are conductive, the lightning current will be transmitted to the far end through the cable and finally converged to the junction box. Next, the potential difference between the junction point, the inverter and the nearby cables is calculated. When the potential difference exceeds the action threshold of the surge protection device (SPD), the SPD will trigger the grounding shunt to achieve protection for the system. The present invention detects and responds to the potential difference changes caused by lightning strikes in real time, protects key equipment from damage in time, reduces the impact of lightning strikes on the overall operation of the photovoltaic array through timely shunting, and improves the stability and reliability of the system.

[0063] The simulation model, method, device and medium of a photovoltaic array grounding system of the present invention are further described in detail below through specific embodiments.

[0064] The simulation model of the photovoltaic array grounding system of the present invention performs lightning protection grounding calculations on photovoltaic power stations and studies the potential distribution of the power stations.

[0065] The present invention first establishes a photovoltaic bracket model, which includes columns, inclined beams and cross beams. The entire photovoltaic bracket is made of steel and connected to the ground grid. The specific parameters are as follows: the short column is 0.6m high, the long column is 2.9m high, and a 0.3m long concrete pile is installed at the bottom of each column; the inclined beam is 3.3m long, and the cross beam uses a 22m long channel steel. In the modeling process, the channel steel is equivalent to a round steel with a radius of 0.045m. The photovoltaic bracket is connected to the ground grid through a grounding down conductor.

[0066] In the present invention, the cable passes through the beam channel steel to form a closed loop, and its potential is close to the potential of the photovoltaic panel. The cables of each photovoltaic array are directly buried underground with a depth of 0.8m. The cables of each photovoltaic module are connected in parallel at the junction box and further connected to the inverter cabinet. SPDs are installed near the junction box and the inverter, and all modules are connected to the photovoltaic grounding system.

[0067] Inject lightning current into one end of one of the photovoltaic modules, calculate the ground potential rise of the photovoltaic support and the corresponding conductor segment of the cable along the line by the moment method, and calculate the potential difference between the photovoltaic support and the cable along the line by subtracting the ground potential rise. Select the point with the largest potential difference and compare it with the withstand voltage design standard of the nearby photovoltaic support to find the breakdown position under lightning strike, and set a conductor at the breakdown point to connect the photovoltaic support and the cable along the line. Calculate the voltage difference between the SPD at the confluence point and the inverter and the nearby components. When the potential difference exceeds the SPD action value, the SPD will act to ground and shunt, which plays a protective role.

[0068] like Figure 3 and Figure 4 As shown in the figure, taking the specification data of a certain simulation as an example, there are six groups of photovoltaic module models, numbered 1-6 from left to right and top to bottom, and a 100kA 1.2 / 50μs lightning current waveform is injected into the end of the No. 1 photovoltaic module model. The maximum potential difference between the channel steel and the cable in each photovoltaic module model is calculated. The results are shown in Table 1. It can be concluded that the No. 1 and No. 4 photovoltaic module models in the photovoltaic array are broken down by the cables along the line, and conductors need to be added to make the two conductive.

[0069] Table 1 Maximum potential difference between channel steel and cable in each photovoltaic module model

[0070] PV module number Maximum potential difference between channel steel and cable (kV) 1 45.19 2 2.11 3 0.93 4 6.39 5 3.18 6 3.25

[0071] Calculate whether the surge protection device (SPD) at the combiner box and the inverter is activated. Under normal circumstances, the SPD remains open. The potential difference between the SPD and the cables along the line is shown in Table 2. The values ​​are all greater than the SPD action value, so it is necessary to add a conductor at the SPD to ground it for shunt.

[0072] Table 2 Potential difference between SPD and cables along the line

[0073] Potential difference (kV) SPD1 at combiner box 7.92 SPD2 at inverter 13.07

[0074] The present invention simplifies the photovoltaic module model by using a method in which the cable along the line is wrapped around the photovoltaic bracket channel steel. The simplified model can calculate the potential distribution of each part of the photovoltaic panel, connect the steel pipe with the photovoltaic bracket to play a diversion role, and build the cable core with insulation coating in parallel with the steel pipe, so that the cable can be directly buried in the soil through the pipe in the electromagnetic field simulation software.

[0075] In summary, the present invention provides a simulation model, method, device and medium for a photovoltaic array grounding system, which constructs a simulation model including photovoltaic brackets, cables, and surge protection devices, and uses electromagnetic field simulation software to relatively accurately simulate the electrical behavior under lightning strikes. The present invention can not only predict risks in advance, but also understand the current, potential distribution and surge protection device operation in real time through simulation results, providing technical support for real-time maintenance of photovoltaic arrays.

[0076] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the specification and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. The simulation model of the photovoltaic array grounding system is characterized by: The simulation model includes a photovoltaic support model, a cable model, a surge protection device model and a simulation calculation module; wherein: The photovoltaic support model includes columns, inclined beams and cross beams; a number of photovoltaic component models are simulated and set in the photovoltaic support model, and the photovoltaic support model is connected to the ground grid through a grounding lead; In the cable model, the simulated cable passes through the crossbeam of the photovoltaic support model to form a closed loop; the closed loop extends to the outside of the photovoltaic support model through the cable and is connected to the simulated junction box and the simulated inverter; The surge protection device model includes two simulated surge protection devices, which are respectively located at the simulated combiner box and the simulated inverter. The surge protection device model is used to perform grounding shunting when it is detected that the potential difference exceeds a preset action threshold; The simulation calculation module is used to calculate the potential difference between the photovoltaic support model and the simulated cable along the line when a lightning current is injected into a photovoltaic component model, and simulate the discharge breakdown phenomenon and the action of the surge protection device model, and calculate the distribution of current and potential of each photovoltaic component model in the simulation model when struck by lightning.

2. The simulation model of the photovoltaic array grounding system according to claim 1, characterized in that: In the cable model, the photovoltaic panels are regarded as equipotential metal plates, and the potential of the photovoltaic panels is represented by the loop potential formed by the simulated cable surrounding the photovoltaic support model along the line.

3. The simulation model of the photovoltaic array grounding system according to claim 1, characterized in that: It also includes a surge protection device action judgment module, which is used to calculate the potential difference between the simulated surge protection device and the nearby cables at the simulated junction box and the simulated inverter. When the potential difference exceeds the action threshold of the simulated surge protection device, the simulated surge protection device performs grounding shunting through an added conductor.

4. The simulation model of the photovoltaic array grounding system according to claim 1, characterized in that: It also includes a simulation result display module, which is used to display the current and potential distribution of each photovoltaic component model in the simulation model when struck by lightning and the action status of the surge protection device model.

5. The simulation model of the photovoltaic array grounding system according to claim 1, characterized in that: In the photovoltaic support model, the crossbeam is modeled as round steel, and the columns are modeled as short columns and long columns. Based on the physical model, the sizes of the columns, inclined beams and crossbeams in the photovoltaic support model are equivalently simulated and set.

6. The simulation model of the photovoltaic array grounding system according to claim 1, characterized in that: The simulation model is constructed based on electromagnetic field simulation software.

7. The simulation model of the photovoltaic array grounding system according to claim 1, characterized in that: In the simulation calculation module, the moment method is used to calculate the distribution of current and potential of each photovoltaic module model in the simulation model when struck by lightning.

8. A simulation method for a simulation model of a photovoltaic array grounding system according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Based on the simulation model, injecting lightning current into a photovoltaic module model in the simulation model; S2, the simulation calculation module calculates the potential difference between the photovoltaic support model and the simulated cables along the line, finds the potential breakdown point and simulates the breakdown phenomenon; S3, the simulation calculation module calculates the potential difference between the simulated surge protection device at the simulated combiner box and the simulated inverter and the nearby simulated cable to determine whether the simulated surge protection device is actuated; S4. Output simulation results, including the current and potential distribution of each component of the photovoltaic array and the action results of the simulated surge protection device.

9. A computer device comprising a memory, a processor and a computer program stored and executed on the memory, characterized in that: When the processor executes the computer program, the steps of the simulation method of the photovoltaic array grounding system according to claim 8 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the simulation method of the photovoltaic array grounding system as claimed in claim 8 are implemented.

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