A method and system for determining the length of a vertical terrestrial device

Abstract

The application provides a vertical grounding device length determination method, comprising the following steps: S1. According to the Winner quadrupole method, the soil resistivity of the area where the wind power plant is located is obtained; S2. According to the preset electrode spacing and the soil resistivity, the soil horizontal layering is inverted to obtain soil structure parameters; S3. According to the soil structure parameters, the vertical grounding device length value range is set, and the length value of the vertical grounding device is determined from the vertical grounding device length value range according to a preset mode; wherein the soil resistivity comprises an actual soil resistivity and a theoretical soil resistivity. The application also provides a vertical grounding device length determination system, which has the same beneficial effects.

Description

Technical Field

[0001] This invention relates to the technical field of wind turbine generators in wind farms, and in particular to a method and system for determining the length of a vertical grounding device. Background Technology

[0002] Studies have found a strong correlation between the grounding resistance of wind turbines and their lightning attraction capabilities. The lightning attraction capability of wind turbines increases with rising impulse grounding resistance. Therefore, enhancing the grounding characteristics of wind turbines and reducing impulse grounding resistance are crucial for improving turbine operational efficiency and resistance to damage.

[0003] Currently, the commonly used resistance reduction measures in engineering are essentially about reducing resistivity or expanding the grounding area. Methods for reducing resistivity include deep burial of grounding devices, soil replacement, and adding resistance-reducing agents. Expanding the grounding area involves connecting the main grounding grid to an auxiliary grounding grid in a low soil resistivity area to increase the size of the grounding grid, or expanding the grounding grid area through natural grounding electrodes. Natural grounding electrodes are frequently used in engineering due to their ease of application, obvious effects, long service life, and low cost. However, their disadvantage is the difficulty of secondary manual modifications after the project is completed. Soil replacement is very expensive and difficult to construct, so it is rarely used in engineering. Adding resistance-reducing agents is based on their stable resistance reduction effect, reasonable cost, and ease of operation; they can be used before foundation construction or later to reduce resistance. However, their disadvantages include susceptibility to rainwater erosion, a relatively short service life, and the need for periodic replacement. While these resistance reduction measures can reduce the impact grounding resistance of wind turbine grounding devices to a certain extent, they cannot simultaneously achieve resistance reduction, economy, and ease of construction.

[0004] Grounding resistance is a crucial parameter in wind turbine grounding design. The primary factor influencing the grounding resistance is the soil resistivity at the location of the wind turbine grounding device. Due to the complexity of geological conditions in mountainous areas where wind turbines are located, it is difficult to describe the actual soil conditions using a single soil model. Existing grounding standards calculate grounding resistance based on uniform soil and a single soil resistivity. In areas with complex soil conditions, the calculated results will deviate significantly from the measured results.

[0005] Therefore, providing a method and system for determining the length of a vertical grounding device that can solve the above problems is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for determining the length of a vertical grounding device. This method is logically clear, safe, effective, reliable, and easy to operate. It can accurately determine the optimal length of the vertical grounding device based on the complex conditions of the actual soil.

[0007] Based on the above objectives, the technical solution provided by the present invention is as follows:

[0008] A method for determining the length of a vertical grounding device includes the following steps:

[0009] The soil resistivity of the wind farm area was obtained using the Winner four-electrode method.

[0010] Soil horizontal stratification is inverted based on the preset electrode spacing and the soil resistivity to obtain soil structure parameters;

[0011] The length range of the vertical grounding device is set according to the soil structure parameters, and the length of the vertical grounding device is determined from the length range of the vertical grounding device according to a preset method.

[0012] The soil resistivity includes: actual soil resistivity and theoretical soil resistivity.

[0013] Preferably, the step of inverting the soil horizontal stratification based on the preset electrode spacing and the soil resistivity to obtain soil structure parameters includes the following steps:

[0014] The first function is established based on the soil resistivity and the least squares method;

[0015] Substitute the first function variable to obtain the second function;

[0016] The soil horizontal stratification is inverted according to the second function to obtain the soil thickness of each layer and the corresponding soil resistivity of each layer.

[0017] The soil structure parameters include: the number of soil layers, the soil thickness, and the soil resistivity of each layer.

[0018] Preferably, the first function is specifically:

[0019]

[0020]

[0021] Where, ρ c ρ represents the actual soil resistivity. m ρ is the theoretical soil resistivity. i Let h be the resistivity of the i-th soil layer. i Let be the thickness of the i-th soil layer.

[0022] Preferably, the substitution of the first function variable to obtain the second function specifically involves:

[0023] make:

[0024] Then the second function is:

[0025]

[0026] Preferably, the soil horizontal stratification is inverted based on the second function, specifically as follows:

[0027] Get ρ in the second function i ′ and h i The minimum value of ′;

[0028] According to ρ in the second function i ′ and h i The minimum value of ′ and the minimum value of the preset polarity are used to invert the horizontal soil stratification to obtain the soil thickness of each layer and the corresponding soil resistivity of each layer.

[0029] Preferably, the step of setting the range of vertical grounding device length values ​​according to the soil structure parameters, and determining the length value of the vertical grounding device from the range of vertical grounding device length values ​​according to a preset method, includes the following steps:

[0030] The vertical grounding device is set to meet the first preset condition according to the soil structure parameters, so as to obtain the first length range of the vertical grounding device.

[0031] The second length range is obtained by determining whether the impulse grounding resistance value corresponding to the length value in the first length range of the vertical grounding device meets the second preset condition.

[0032] The length of the vertical grounding device is determined based on the second length range and the preset formula.

[0033] Preferably, the preset formula is as follows:

[0034]

[0035] Where η is the length utilization rate of the vertical grounding device, R0 is the impulse grounding resistance value without the addition of the vertical grounding device, R is the impulse grounding resistance value after the addition of the vertical grounding device, L is the length of a single vertical grounding device, and n is the total number of vertical grounding devices.

[0036] A system for determining the length of a vertical grounding device includes: a soil resistivity module, a soil structure parameter module, and a length determination module;

[0037] The soil resistivity module is used to obtain the soil resistivity of the area where the wind farm is located according to the Winner four-electrode method.

[0038] The soil structure parameter module is used to invert the horizontal stratification of soil based on the preset electrode spacing and the soil resistivity to obtain soil structure parameters.

[0039] The length determination module is used to set the length range of the vertical grounding device according to the soil structure parameters, and to determine the length value of the vertical grounding device from the length range of the vertical grounding device according to a preset method.

[0040] The soil resistivity includes: actual soil resistivity and theoretical soil resistivity.

[0041] The method for determining the length of a vertical grounding device provided by this invention involves obtaining the soil resistivity of the wind farm area using the Winner four-electrode method; performing inversion on the horizontal soil stratification using a preset electrode spacing and the obtained soil resistivity to obtain soil structure parameters; setting a range of values ​​for the length of the vertical grounding device based on the soil structure parameters; and determining the length value from this range according to a preset method. The soil resistivity includes both actual soil resistivity and theoretical soil resistivity.

[0042] Compared with existing technologies, this invention takes into account the error between actual soil resistivity and theoretical soil resistivity, and constructs a multi-factor soil model to describe the actual soil conditions. Specifically, it obtains soil structure parameters, sets the range of values ​​for the length of the vertical grounding device based on the soil structure parameters, and determines the length of the vertical grounding device from the range of values ​​through a preset method, thereby accurately determining the optimal length of the vertical grounding device.

[0043] The vertical grounding device length determination system also provided by this invention has the same technical concept and solves the same technical problem as the vertical grounding device length determination method, and should therefore have the same beneficial effects, so it will not be described in detail here. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A flowchart illustrating a method for determining the length of a vertical grounding device according to an embodiment of the present invention;

[0046] Figure 2 A flowchart of step S2 provided in an embodiment of the present invention;

[0047] Figure 3This is a flowchart of the inversion method in step S2 provided in an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the inversion results provided in an embodiment of the present invention;

[0049] Figure 5 A flowchart of step S3 provided in an embodiment of the present invention;

[0050] Figure 6 A schematic diagram showing the calculation results of impulse grounding resistance for different lengths of the vertical grounding device provided in the embodiments of the present invention;

[0051] Figure 7 A schematic diagram illustrating the relationship between the utilization rate per unit length and the length of the vertical grounding device, provided for an embodiment of the present invention.

[0052] Figure 8 This is a schematic diagram of a vertical grounding device length determination system provided in an embodiment of the present invention. Detailed Implementation

[0053] 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, and 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.

[0054] The embodiments of this invention are written in a progressive manner.

[0055] This invention provides a method and system for determining the length of a vertical grounding device. It primarily addresses the technical problem in the prior art where the calculated length of the vertical grounding device is inaccurate due to a single soil model.

[0056] like Figure 1 As shown, a method for determining the length of a vertical grounding device includes the following steps:

[0057] S1. Obtain the soil resistivity of the area where the wind farm is located using the Winner four-electrode method;

[0058] S2. Invert the horizontal soil stratification based on the preset electrode spacing and soil resistivity to obtain soil structure parameters;

[0059] S3. Set the length range of the vertical grounding device according to the soil structure parameters, and determine the length of the vertical grounding device from the length range according to the preset method;

[0060] Soil resistivity includes both actual soil resistivity and theoretical soil resistivity.

[0061] In step S1, the Winner four-electrode method is a commonly used method for measuring soil resistivity, such as... Figure 2 As shown, a is the distance between adjacent electrodes, and h is the electrode burial depth. Figure 2 The outer pair of electrodes are current electrodes, and the inner pair are voltage electrodes. Keeping the current I constant, changing the value of a yields a series of voltage values. When the value of a is very small, most of the current flows through the surface soil. As the value of a increases, the current penetrates deeper into the soil in both vertical and horizontal directions, and more and more current flows through the deeper soil layers. The deeper soil layers will affect the apparent resistivity. Therefore, the relationship between voltage and current when the electrode spacing changes can reflect the geostratification model and parameters. The soil resistivity of the wind farm area can be obtained using the Winner four-electrode method.

[0062] In this embodiment, a 1.5m long and 3cm diameter steel pipe grounding electrode was driven into the high soil resistivity mountainous area where the wind farm is located. The apparent soil resistivity of the area was measured using the Wenner equidistant four-electrode method. The measurement data are shown in Table 1.

[0063] Table 1 Actual soil resistivity measurement data

[0064]

[0065] In step S2, inversion is a theoretical method for inferring physical system model parameters from measured data. The soil horizontal stratification is inverted using preset interpole spacing and soil resistivity to obtain the soil structural parameters.

[0066] In step S3, when the length of the vertical grounding device is too long, the current dissipation capacity of the vertical grounding device will reach saturation, and its resistance reduction effect will tend to slow down, and it will also cause waste of construction materials. Therefore, when selecting the optimal length of the vertical grounding device, the following two points should be considered: (1) The primary goal is to improve the resistance reduction effect of the grounding device so that it meets the target value; (2) After achieving the resistance reduction target value, it is also necessary to analyze its technical and economic benefits beyond resistance reduction, so as to reduce the difficulty of on-site construction and avoid waste of tower grounding materials. Based on this, a preset formula is defined to determine the length of the vertical grounding device from the range of vertical grounding device length values.

[0067] like Figure 2 As shown, preferably, step S2 includes the following steps:

[0068] A1. Establish the first function based on soil resistivity and the least squares method;

[0069] A2. Substitute the variables of the first function to obtain the second function;

[0070] A3. Invert the soil horizontal stratification according to the second function to obtain the soil thickness of each layer and the corresponding soil resistivity of each layer;

[0071] Among them, soil structure parameters include: number of soil layers, soil thickness, and soil resistivity of each layer.

[0072] In steps A1 to A3, the inversion calculation of the horizontal N-layer soil structure is essentially an optimization problem with 2N-1 variables. By changing the interelectrode spacing a, M apparent resistivity measurements P of the soil are obtained. m Calculate the corresponding M soil apparent resistivity values ​​P c Using the principle of the complex image method, the actual calculated values ​​P of the corresponding M soil apparent resistivity can be obtained. m The least squares method is used to model the calculated values ​​of M soil resistivity and then constraints are added. The constrained optimization problem is transformed into an unconstrained optimization problem by variable substitution. Then, the unconstrained optimization method is used to inversely derive the number of equivalent horizontally stratified soil layers, the soil resistivity of each layer, and the thickness.

[0073] Preferably, the first function is:

[0074]

[0075]

[0076] Where, ρ c ρ represents the actual soil resistivity. m ρ is the theoretical soil resistivity. i Let h be the resistivity of the i-th soil layer. i Let be the thickness of the i-th soil layer.

[0077] In this embodiment, the first function is obtained by modeling using the least squares method as shown in the above formula, and constraints are added as shown in the above formula;

[0078] Preferably, the first function variable is substituted to obtain the second function, specifically as follows:

[0079] make:

[0080] The second function is:

[0081]

[0082] In this embodiment, the constraints on the unknowns in the first function are removed, and the nonlinear optimization problem with constraints is transformed into an unconstrained nonlinear optimization problem, resulting in the second function as shown in the above equation.

[0083] like Figure 3 As shown, preferably, the inversion in step S2 specifically includes:

[0084] B1. Obtain ρ′ from the second function i and h′ i The minimum value;

[0085] B2. Based on ρ′ in the second function i and h′ i The minimum value and the minimum value among the preset inter-electrode spacing are used to invert the soil horizontal stratification to obtain the soil thickness of each layer and the corresponding soil resistivity of each layer.

[0086] In steps B1 to B2, the minimum values ​​of the soil resistivity and soil thickness of the i-th layer in the second function and the minimum value of the preset inter-electrode spacing are obtained by calculating and inverting the soil horizontal stratification to obtain the soil thickness and corresponding soil resistivity of each layer.

[0087] Specifically, the measured interelectrode spacing and the measured apparent resistivity of the soil are plotted as a curve, and the number of soil layers n is equal to the number of points in the curve of apparent resistivity changing with interelectrode spacing that cause fluctuations in the curve (including extreme points and non-extreme points that cause fluctuations in the curve).

[0088] Following the measurement order from smallest to largest interelectrode spacing, other points causing curve fluctuations (excluding the first and last points of the curve) correspond to the 2nd to (n-1th)th soil layers. The initial value of the resistivity of the i-th soil layer is taken as the resistivity measurement value at that fluctuation point. For the thickness of each soil layer, let h′... i If the initial value h of each soil layer is equal to the interpolar spacing corresponding to the i-th point that causes curve fluctuation (i = 2, 3, ..., n-1), then... i =(h′) i -h′ i-1 )

[0089] The apparent resistivity of the soil measured when the electrode spacing is at its minimum is taken as the initial value of the resistivity of the first soil layer, and the minimum electrode spacing is its initial thickness. The last measured value, that is, the apparent resistivity of the soil measured when the electrode spacing is at its maximum, is taken as the initial value of the resistivity of the last soil layer, and the initial value of the thickness is obtained by the method described above.

[0090] In this embodiment, soil horizontal stratification is inverted based on the measured interelectrode spacing and corresponding apparent soil resistivity. The steepest descent method is used to calculate the RMS error between the experimentally measured soil resistivity and the theoretically calculated soil resistivity curves. The optimal combination is selected, and the inversion result is as follows: Figure 4 As shown;

[0091] After performing soil horizontal stratification inversion, the specific structure of the soil in this area can be clearly understood. The soil stratification inversion map shows that the soil in this area is divided into three layers, and the specific thickness and soil resistivity of each layer are shown in Table 2.

[0092] Table 2 Specific parameter values ​​for soil layer inversion

[0093]

[0094] like Figure 5 As shown, preferably, step S3 includes the following steps:

[0095] C1. Set the vertical grounding device to meet the first preset condition according to the soil structure parameters, so as to obtain the first length range of the vertical grounding device;

[0096] C2. The impulse grounding resistance value corresponding to the length value in the first length range of the vertical grounding device satisfies the second preset condition, so as to obtain the second length range;

[0097] C3. Determine the length of the vertical grounding device based on the second length range and the preset formula.

[0098] Preferably, the preset formula is as follows:

[0099]

[0100] Where η is the length utilization rate of the vertical grounding device, R0 is the impulse grounding resistance value without the addition of the vertical grounding device, R is the impulse grounding resistance value after the addition of the vertical grounding device, L is the length of a single vertical grounding device, and n is the total number of vertical grounding devices.

[0101] Before steps C1 to C3, the optimal length utilization rate is defined as a measure of the resistance reduction efficiency of the vertical grounding device, thereby determining the optimal length of the vertical grounding device.

[0102] In steps C1 to C3, the vertical grounding device is set to meet the first preset condition by setting the land structure parameters, thereby obtaining the first length value range. The impulse grounding resistance value corresponding to the length value is obtained to meet the second preset condition, thereby obtaining the second length value range. The length value of the vertical grounding device is determined in the second length value range by using a preset formula.

[0103] Specifically, based on the actual soil stratification structure of the wind farm in the mountainous area obtained by soil stratification inversion, the length range of the vertical grounding device is initially set so that it can contact the low resistivity soil layer, because in areas with low soil resistivity, the vertical grounding device can achieve a better current dissipation effect.

[0104] In the middle of a soil layer with low soil resistivity, the length of the vertical grounding device is changed, and the corresponding impulse grounding resistance value of the transmission tower grounding device is calculated to further determine the length range of the vertical grounding device that makes the overall grounding device resistance reduction effect significant.

[0105] Within a length range where resistance reduction is significant, the optimal length utilization rate is used as a measure of the resistance reduction efficiency of the vertical grounding device. The variation law of the optimal length utilization rate of the vertical grounding device with its length is analyzed to determine the optimal length of the vertical grounding device, so that the vertical grounding device can achieve optimal technical and economic benefits while meeting the resistance reduction effect.

[0106] In this embodiment, CDEGS electromagnetic simulation software will be used to model the wind turbine grounding device. In CDEGS software, a horizontal circular ring is represented by a regular octagon. The radius of the horizontal grounding ring is 16m, and the side length of the regular octagon is 12.5m. Eight vertical grounding devices are installed on the equipotential ring, spaced approximately every 12m. The grounding device is buried at a depth of 0.8m.

[0107] Based on the thickness of each soil layer under the three-layer geological structure in Table 2, the range of values ​​for the length of the vertical grounding device is set to [3 5 8 10 12 15 18 20]. The calculation results of the impulse grounding resistance for different lengths of the vertical grounding device are as follows: Figure 6 As shown;

[0108] The utilization rate per unit length of the vertical grounding device is used as the basis for finally determining the length of the vertical grounding device. Figure 6 Substituting the calculated result of the impulse grounding resistance into the above preset formula, the relationship between the utilization rate per unit length and the length of the vertical grounding electrode is obtained, as follows: Figure 7 As shown;

[0109] Within the range of vertical grounding device lengths that significantly reduce the overall resistance of the grounding system, the utilization rate per unit length is relatively high when the vertical grounding device length is between 5m and 10m; among them, the utilization rate per unit length is highest when the length is 8m. This is because when the vertical grounding device is shorter, the resistance reduction effect is not obvious; while when the vertical grounding device is longer, the soil participating in current dissipation tends to be saturated, and an excessively long vertical grounding device leads to material waste.

[0110] In summary, considering both resistance reduction and the optimal utilization rate of the vertical grounding device, the optimal length of the vertical grounding device is determined to be 8m.

[0111] like Figure 8 As shown, a vertical grounding device length determination system includes: a soil resistivity module, a soil structure parameter module, and a length determination module;

[0112] The soil resistivity module is used to obtain the soil resistivity of the area where the wind farm is located according to the Winner four-electrode method.

[0113] The soil structure parameter module is used to invert the horizontal soil stratification based on the preset electrode spacing and soil resistivity to obtain soil structure parameters.

[0114] The length determination module is used to set the length range of the vertical grounding device according to the soil structure parameters, and to determine the length of the vertical grounding device from the length range according to a preset method.

[0115] Soil resistivity includes both actual soil resistivity and theoretical soil resistivity.

[0116] In practical application, the soil resistivity module obtains the soil resistivity of the wind farm area according to the Winner four-electrode method and sends the soil resistivity to the soil structure parameter module. The soil structure parameter module performs inversion on the horizontal soil stratification according to the preset electrode spacing and soil resistivity to obtain soil structure parameters, and sends the soil structure parameters to the length determination module. The length determination model sets the length range of the vertical grounding device according to the soil structure parameters, and determines the length value of the vertical grounding device from the vertical grounding device length range according to the preset method.

[0117] In the embodiments provided in this application, it should be understood that the disclosed methods and systems can be implemented in other ways. The system embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple modules or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, and can be electrical, mechanical, or other forms.

[0118] Furthermore, in the various embodiments of the present invention, each functional module can be fully integrated into a processor, or each module can be a separate device, or two or more modules can be integrated into a device; each functional module in the various embodiments of the present invention can be implemented in hardware or in the form of hardware plus software functional units.

[0119] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by program instructions and related hardware. The aforementioned program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, they perform the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.

[0120] It should be understood that the use of terms such as "system," "device," "unit," and / or "module" in this application is merely one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0121] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0122] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more.

[0123] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0124] If a flowchart is used in this application, it is used to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0125] The foregoing has provided a detailed description of a method and system for determining the length of a vertical grounding device according to the present invention. The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the length of a vertical grounding device, characterized in that, Includes the following steps: The soil resistivity of the wind farm area was obtained using the Winner four-electrode method. Soil horizontal stratification is inverted based on the preset electrode spacing and the soil resistivity to obtain soil structure parameters; The length range of the vertical grounding device is set according to the soil structure parameters, and the length of the vertical grounding device is determined from the length range of the vertical grounding device according to a preset method. The soil resistivity includes: actual soil resistivity and theoretical soil resistivity; The step of inverting the soil horizontal stratification based on the preset electrode spacing and the soil resistivity to obtain soil structure parameters includes the following steps: The first function is established based on the soil resistivity and the least squares method; Substitute the first function variable to obtain the second function; The soil horizontal stratification is inverted according to the second function to obtain the soil thickness of each layer and the corresponding soil resistivity of each layer. The soil structure parameters include: number of soil layers, soil thickness, and soil resistivity of each layer; The first function is specifically: ； ; in, This represents the actual soil resistivity. Theoretical soil resistivity; Let be the resistivity of the i-th soil layer. Let be the thickness of the i-th soil layer; The substitution of the first function variable to obtain the second function specifically involves: make: ; Then the second function is: ； The soil horizontal stratification is inverted based on the second function, specifically as follows: Get the second function and The minimum value; According to the second function and The minimum value of the soil layer and the minimum value of the preset inter-electrode spacing are used to invert the soil horizontal stratification in order to obtain the soil thickness of each layer and the corresponding soil resistivity of each layer. The step of setting the length range of the vertical grounding device according to the soil structure parameters, and determining the length of the vertical grounding device from the length range according to a preset method, includes the following steps: The vertical grounding device is set to meet the first preset condition according to the soil structure parameters, so as to obtain the first length range of the vertical grounding device. The second length range is obtained by determining whether the impulse grounding resistance value corresponding to the length value in the first length range of the vertical grounding device meets the second preset condition. The length of the vertical grounding device is determined based on the second length range and the preset formula. The preset formula is specifically as follows: ； Where η is the length utilization rate of the vertical grounding device, R0 is the impulse grounding resistance value without the addition of the vertical grounding device, R is the impulse grounding resistance value after the addition of the vertical grounding device, L is the length of a single vertical grounding device, and n is the total number of vertical grounding devices.

2. A system for determining the length of a vertical grounding device, applied to the method for determining the length of a vertical grounding device as described in claim 1, characterized in that, include: Soil resistivity module, soil structure parameter module, and length determination module; The soil resistivity module is used to obtain the soil resistivity of the area where the wind farm is located according to the Winner four-electrode method. The soil structure parameter module is used to invert the horizontal stratification of soil based on the preset electrode spacing and the soil resistivity to obtain soil structure parameters. The length determination module is used to set the length range of the vertical grounding device according to the soil structure parameters, and to determine the length value of the vertical grounding device from the length range of the vertical grounding device according to a preset method. The soil resistivity includes: actual soil resistivity and theoretical soil resistivity.

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