Wind turbine generator grounding geology and soil exploration analysis method

Abstract

The invention provides a wind turbine generator grounding geology and soil exploration analysis method, and belongs to the field of wind turbine geological exploration. The method mainly comprises the following steps: firstly, selecting a proper exploration site for field observation; then, testing the soil resistivity at different positions and directions by adopting a Wenner quadrupole method to obtain sufficient test data; and finally, the collected measurement data and the fitting function are utilized to inversely calculate the distribution conditions of the soil in the vertical and horizontal directions, and an accurate soil structure model is constructed. Moreover, the method can also perform correction processing on test data so as to adapt to the influence of factors such as seasonal variation on the test result. The method has the advantages of being easy to operate, accurate in result, high in adaptability and the like, the problems existing in the prior art can be effectively solved, and the accuracy and scientificity of wind turbine generator grounding design are greatly improved.

Description

Technical Field

[0001] The invention belongs to the field of wind turbine geological exploration, and more specifically relates to a grounding geology and soil exploration and analysis method for a wind turbine set. Background Art

[0002] Wind power generation is a clean energy source that has developed rapidly in recent years. Wind turbines are the main equipment in wind power generation systems, and the correct grounding method plays a vital role in ensuring the safe operation of equipment and the stability of power system operation. At the same time, soil resistivity is an important parameter in grounding grid design, which affects the resistance value of the grounding grid and the distribution of grounding resistance.

[0003] In traditional geological exploration and analysis, soil resistivity test data is usually used for exploration and analysis, and the grounding design plan is adjusted according to the test results. However, because soil resistivity is affected by many factors, such as soil water content, soil type, underground mineral distribution, and seasonal changes, the soil resistivity in different places and seasons can vary greatly.

[0004] In addition, traditional geological exploration and analysis methods also have some limitations. First, the test results depend on the selection of the test point location and the performance of the test instrument; second, the traditional method focuses on single-point measurement and cannot provide a detailed description of the three-dimensional distribution of the soil; finally, simply conducting grounding design based on experience may lead to a large discrepancy between the design results and the actual situation.

[0005] Especially in karst geological environments, where underground limestone is severely eroded, the landforms are complex, and there are large differences in soil types and resistivity. Traditional exploration and analysis methods often find it difficult to accurately depict the actual soil conditions in such areas and cannot fully meet the requirements of wind turbine grounding design.

[0006] Therefore, it is urgently necessary to develop a geological and soil exploration and analysis method that can model the soil around wind turbines in complex geological environments and more accurately predict soil resistivity. Summary of the invention

[0007] The present invention aims to solve the problem faced by the prior art in exploring and analyzing the soil around wind turbines in complex geological environments, such as karst geological environments, so as to more accurately obtain the soil resistivity, help design a grounding network that conforms to the actual situation, and ensure the safe and reliable operation of the wind turbines.

[0008] In order to achieve the above object, the present invention is implemented by adopting the following technical scheme: the method comprises:

[0009] Step 1: determine the surrounding environment of the wind turbine that needs to be explored and analyzed, and conduct field surveys at the selected locations;

[0010] Step 2: Use the Wenner quadrupole method to test and collect data on soil resistivity at different locations and orientations;

[0011] Step three, use the soil apparent resistivity measurement data at different test intervals to establish a fitting function, and use the optimization method to invert and infer the soil distribution in the horizontal and vertical directions, the resistivity and thickness of each layer to construct a soil structural model.

[0012] In one embodiment, step two includes performing forward and reverse tests in a cross-arrangement test orientation.

[0013] In one embodiment, in step three, the soil structure model constructed is based on the characteristics of the peaks, valleys, bottoms and karst geological environment.

[0014] In one embodiment, the method includes determining the most suitable land for laying the resistance reduction grounding grid based on preliminary analysis.

[0015] In one embodiment, the determination of the land most suitable for laying the resistance-reducing grounding grid is accomplished by performing a preliminary analysis of apparent soil resistivity test data.

[0016] In one embodiment, the method includes calculating the thickness of the upper layer and the resistivity of the upper and lower layers of the soil based on test data and an approximate formula for soil resistivity.

[0017] In one embodiment, the method is based on soil resistivity test data and uses a seasonal factor to correct the resistivity.

[0018] In one aspect, the method includes inverting soil resistivity test data to determine the resistivity and thickness of each layer in a soil exhibiting a two-layer structure.

[0019] In one embodiment, the Wenner quadrupole method measures at intervals of 1m, 2m, 3m, 5m, 10m, and 20m, and is used to detect soil at a depth of about 15m underground.

[0020] In one solution, the resistivity of the upper and lower soil layers is calculated using a double-layer soil refractive index calculation formula.

[0021] Beneficial effects of the present invention:

[0022] 1) Accurate measurement: This method uses the Wenner quadrupole method to test and collect data on soil resistivity at different locations and orientations, which can more accurately obtain resistivity information of the soil around the wind turbine. In addition, this method can also more comprehensively understand the resistivity distribution of the soil by conducting forward and reverse tests.

[0023] 2) Model fitting: This method uses the soil apparent resistivity measurement data at different test intervals to establish a fitting function, infer the distribution of soil in the horizontal and vertical directions, and construct an accurate soil structure model, providing accurate data support for grounding grid design.

[0024] 3) Strong adaptability: This method has strong adaptability to karst geological conditions and can accurately complete the measurement and analysis of soil resistivity even in complex geological environments.

[0025] 4) Improve work efficiency: Compared with traditional exploration methods, this method can improve work efficiency and reduce the consumption of manpower and material resources.

[0026] 5) Maintain equipment safety: By assisting in the design of a grounding network that meets actual conditions, equipment safety hazards caused by poor grounding can be effectively prevented, ensuring the safe and reliable operation of wind turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of the present invention;

[0028] Figure 2 This is a soil resistivity test data diagram of Plot 1 of the present invention;

[0029] Figure 3 This is the soil resistivity test data diagram of Plot 2 of the present invention. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Typical embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in the present invention. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0031] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the present invention in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Typical embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in the present invention. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0032] like Figure 1 As shown, the grounding geology and soil exploration and analysis method of the wind turbine generator set includes:

[0033] Step 1: Determine the surrounding environment of the wind turbine that needs to be explored and analyzed, and conduct a field survey at the selected location.

[0034] Usually, exploration is carried out at the bottom of peaks and valleys where the soil layer is thicker. In the karst geological environment, due to soil erosion, more soil is deposited at the bottom of peaks and valleys.

[0035] Step 2: Use the Wenner quadrupole method to test and collect data on soil resistivity at different locations and orientations.

[0036] The Wenner quadrupole method is used to measure soil resistivity. Soil resistance is measured at different locations and orientations to collect test data. Generally, a cross-shaped test orientation should be used. Forward and reverse tests can analyze soil distribution in all directions. However, due to terrain restrictions, measurements can often only be made in one direction along the valley bottom.

[0037] Two plots were selected in the valley between the two units, identified as Plot 1# and Plot 2#, which are about 350 meters apart along the valley bottom road. Soil resistivity tests were conducted on Plot 1# and Plot 2# respectively, using the equidistant Wenner quadrupole method to measure soil resistivity in the forward and reverse directions, with spacings of 1m, 2m, 3m, 5m, 10m, and 20m. Six sets of data were collected, which can detect an underground depth of about 15m.

[0038] (1) Soil resistivity test data of plot 1#ρ a =f(a) curve description is as follows Figure 2 As shown. The curve is relatively smooth, with a jump at a spacing of 10m. Analysis shows that the soil of this plot is distributed in a double-layer structure above 15m in the vertical direction, and the resistivity of the lower layer of soil is relatively high; the forward and reverse test data curves are almost overlapped, indicating that the forward and reverse consistency of the test current field is good, and the analysis shows that the soil is evenly distributed in the horizontal direction.

[0039] (2) Soil resistivity test data ρ of plot 2# a=f(a) curve description is as follows Figure 3 As shown. The test spacing is 1m-10m, and the curve is relatively flat. At the spacing of 20m, there is a significant jump. Analysis shows that the soil of this plot is distributed in a double-layer structure above 15m in the vertical direction, and the resistivity of the lower soil is very high; the forward and reverse test data curves are obviously bifurcated at a spacing of 20m, indicating that the test current field is distorted within a range of 15m-30m from the center point. Analysis shows that the deep soil layer of this plot is heterogeneous in the horizontal direction, and there is a possibility of geological faults (karst caves) in the lateral direction of the test direction.

[0040] (3) Based on the above analysis, a preliminary assessment was conducted to determine that Plot 1# is more suitable for laying and installing a resistance-reducing grounding grid.

[0041] Step three, use the soil apparent resistivity measurement data at different test intervals to establish a fitting function, and use the optimization method to invert and infer the soil distribution in the horizontal and vertical directions, the resistivity and thickness of each layer to construct a soil structural model.

[0042] (1) Thickness of upper soil layer s

[0043] After preliminary analysis of plot 1#, the soil distribution is a double-layer structure, and the Wennar equidistant quadrupole method soil resistivity approximate formula is:

[0044] ρ a =ρ2-(ρ2-ρ1)е -a / b (2-е -a / b ) (Formula 4.1)

[0045] Where ρ1: apparent soil resistivity of the surface, Ω·m;

[0046] ρ2: deep apparent soil resistivity, Ω·m;

[0047] a: test spacing, m;

[0048] b: Constant determined by the thickness of the topsoil, m.

[0049] Inverse calculation:

[0050] k=(ρ2-ρ a ) / (ρ2-ρ1)

[0051] When the condition 0﹤k≤1 is met, the following formula can be used for calculation:

[0052]

[0053] From this calculation, we can get: b = 9.6m

[0054] According to Table 1, δ is taken as 5.

[0055] Table 1 δ values ​​used to determine apparent resistivity curve coefficients

[0056]

[0057] Therefore, the thickness of the upper soil layer is: s = b / δ = 1.92m

[0058] (2) Upper soil resistivity ρ1:

[0059] Apparent soil resistivity ρ of plot 1# a =f(a) curve intersects with the vertical axis, and it can be determined that the resistivity ρ1 of the upper soil is 500Ω·m.

[0060] (3) Lower soil resistivity ρ2:

[0061] The double-layer soil refractive index is calculated using the formula:

[0062] K=(ρ2-ρ1) / (ρ2+ρ1) (Formula 4.4)

[0063] The calculated K = 0.76

[0064] Using the formula:

[0065] ρ2=ρ1(1+K) / (1-K)(Formula 4.5)

[0066] The calculated resistivity ρ2 of the lower soil is 3666Ω·m.

[0067] Plot soil structure model

[0068] The soil is evenly distributed horizontally along the peak-to-valley direction; the vertical section above 15m is a double-layer structure, with an average soil resistivity of 500Ω·m and an average thickness of 1.9m in the upper layer, and an average soil resistivity of 3666Ω·m in the lower layer.

[0069] Considering that it was rainy and snowy the day before the soil resistivity test of this plot, and the soil was relatively moist, soil resistivity correction should be made during the design and calculation of the resistance reduction project. This plot is humus clay, and the seasonal coefficient ψ can be taken as 1.2, and the soil resistivity ρ value should be multiplied by ψ.

[0070] Influence of soil structure on grounding grid

[0071] Luxi Yongsan, Kongzhaopu wind farms and other similar karst geology and landforms, the shallow soil (above 20m) is basically a double-layer structure. The upper soil has a low resistivity due to the deposition of humus soil. The installation of horizontal grounding electrodes has a better resistance reduction effect, while the resistivity of the second layer of soil is extremely high. The resistance reduction effect of laying vertical grounding electrodes is not obvious. Therefore, the main grounding grid and resistance reduction grounding grid of wind farms under karst geological conditions are mainly based on the installation of horizontal grounding electrodes.

[0072] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM).

[0073] It should be understood that the detailed description of the technical solutions of the present invention by means of the preferred embodiments is illustrative rather than restrictive. A person skilled in the art may modify the technical solutions described in the embodiments, or replace some of the technical features by equivalents, based on reading the specification of the present invention; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for grounding geology and soil exploration and analysis of wind turbines, characterized in that: The method includes: Step 1: determine the surrounding environment of the wind turbine that needs to be explored and analyzed, and conduct field surveys at the selected locations; Step 2: Use the Wenner quadrupole method to test and collect data on soil resistivity at different locations and orientations; Step three, use the soil apparent resistivity measurement data at different test intervals to establish a fitting function, and use the optimization method to invert and infer the soil distribution in the horizontal and vertical directions, the resistivity and thickness of each layer to construct a soil structural model.

2. A method for grounding geology and soil exploration and analysis of a wind turbine according to claim 1, characterized in that: The step 2 includes performing forward and reverse tests in a cross-arranged test orientation.

3. A method for grounding geology and soil exploration and analysis of a wind turbine according to claim 1, characterized in that: In the step three, the soil structure model constructed is based on the characteristics of the peak valley bottom and karst geological environment.

4. A method for grounding geology and soil exploration and analysis of a wind turbine according to any one of claims, characterized in that: The method includes determining the most suitable land for laying the resistance reduction grounding grid based on preliminary analysis.

5. A method for grounding geology and soil exploration and analysis of wind turbines according to claim 4, characterized in that: The determination of the land most suitable for laying the resistance-reducing grounding grid is accomplished by conducting a preliminary analysis of the apparent soil resistivity test data.

6. A method for grounding geology and soil exploration and analysis of a wind turbine according to claim 1, characterized in that: The method comprises calculating the thickness of the upper layer and the resistivity of the upper and lower layers of the soil according to the test data and the approximate formula of the soil resistivity.

7. A method for grounding geology and soil exploration and analysis of a wind turbine according to claim 1, characterized in that: The method is based on soil resistivity test data and uses a seasonal coefficient to correct the resistivity.

8. A method for grounding geology and soil exploration and analysis of a wind turbine according to claim 1, characterized in that: The method includes inverting soil resistivity test data to determine the resistivity and thickness of each layer in the soil exhibiting a double-layer structure.

9. A method for grounding geology and soil exploration and analysis of a wind turbine according to claim 1, characterized in that: The Wenner quadrupole method has measurement intervals of 1m, 2m, 3m, 5m, 10m, and 20m, and is used to detect soil at a depth of about 15m underground.

10. A method for grounding geology and soil exploration and analysis of a wind turbine according to claim 9, characterized in that: The resistivity of the upper and lower soil layers is calculated using the double-layer soil refractive coefficient calculation formula.

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