A fan foundation attached grounding grid and a construction method thereof

Abstract

The application is a fan foundation attached grounding net and a construction method thereof. The grounding net comprises a grounding body, a top voltage equalizing ring, a graphite-based flexible grounding wire, a first non-metallic conductive coiled material, an upper anchor plate, and a second non-metallic conductive coiled material. The grounding body, the top voltage equalizing ring, the graphite-based flexible grounding wire, the first non-metallic conductive coiled material, and the second non-metallic conductive coiled material form a lightning protection grounding system together with the ground. The grounding net is simple to construct, can improve the durability of the grounding conductor of the fan foundation, is easy to ensure the low impedance characteristics of the grounding net, and is not affected by the earthwork operation around the fan foundation.

Description

Technical Field

[0001] This invention relates to the technical field of wind turbine foundation grounding, and in particular to an attached grounding grid for wind turbine foundations and its construction method. Background Technology

[0002] Wind power, as a crucial component of clean and renewable energy, has experienced rapid development globally. Wind turbines are typically installed in open, exposed areas, such as mountaintops, plains, or near the coast, making them high-risk targets for lightning strikes. Lightning strikes can severely damage the electrical and control systems of wind turbines, causing significant direct economic losses and downtime, and may also trigger fires and threaten personnel safety. The wind turbine grounding system, through a deeply buried foundation grounding grid, safely and rapidly discharges lightning current into the ground, making it a critical element in ensuring the safe and stable operation of wind turbines.

[0003] The conventional practice for wind turbine foundation grounding grids involves installing several equipotential rings inside the wind turbine foundation. These rings are connected by galvanized flat steel, with conductors connecting the upper part of each ring to an upper anchor plate, and galvanized flat steel extending from the lower part. Horizontal grounding rings made of copper or galvanized steel are laid below the frost depth around the wind turbine foundation, forming an electrical path through conductors connected to the leads from the equipotential rings. To reduce resistivity, several radial conductors are evenly laid along the circumference of the horizontal grounding rings, or connected to grounding electrodes such as copper-clad steel rods or carbonized grounding blocks, and covered with resistivity-reducing clay material. In recent years, some projects have attempted to use steel mesh as a natural grounding electrode, with connection points leading to external grounding devices. However, due to the long-term burial of the grounding grid in a humid environment, the grounding conductor is susceptible to corrosion, leading to a reduction in conductor cross-sectional area and an increase in resistance. Corrosion can also cause connection failures at grounding grid joints, resulting in high maintenance and replacement costs. Furthermore, earthwork operations around the wind turbine foundation can easily damage the grounding grid.

[0004] Therefore, there is an urgent need for a durable, low-impedance, and easy-to-construct grounding method for wind turbine foundations to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] The present invention aims to address the shortcomings of the prior art by providing a wind turbine foundation attached grounding grid and its construction method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a wind turbine foundation attached grounding grid, comprising:

[0007] The grounding electrode is installed inside the wind turbine foundation;

[0008] The top equalizing ring is installed at the top of the wind turbine foundation and connected to the grounding electrode.

[0009] A graphite-based flexible grounding wire, with one end connected to the grounding electrode and the other end led out to the wind turbine foundation;

[0010] The first non-metallic conductive roll is pasted around the wind turbine foundation and reliably connected to the graphite-based flexible grounding wire;

[0011] The upper anchor plate is installed on top of the wind turbine foundation and connected to the top equalizing ring via a wire.

[0012] The second non-metallic conductive roll is pasted on the outside of the first non-metallic conductive roll, and the graphite-based flexible grounding wire is fixed between the first non-metallic conductive roll and the second non-metallic conductive roll.

[0013] The grounding electrode, the top equalizing ring, the graphite-based flexible grounding wire, the first non-metallic conductive roll, the second non-metallic conductive roll, and the earth together form a lightning protection grounding system.

[0014] Specifically, the grounding electrode includes an inner equipotential ring, an outer equipotential ring, radial flat steel bars, and lead-out flat steel bars. The inner and outer equipotential rings are concentrically set at the bottom of the wind turbine foundation. Several radial flat steel bars are welded between the inner and outer equipotential rings. The outer equipotential ring extends to the edge of the wind turbine foundation through the radial flat steel bars and connects to the graphite-based flexible grounding wire, which is then led out by the graphite-based flexible grounding wire. The inner equipotential ring is led out of the wind turbine foundation column and connected to the top equipotential ring through four lead-out flat steel bars.

[0015] Specifically, the portion of the flat steel exposed on the fan foundation is hot-dip galvanized and connected by annular galvanized flat steel to form a top equalizing ring.

[0016] Specifically, the inner ring equalizing ring, the outer ring equalizing ring, and the radial flat steel are spot-welded to the foundation steel bars at the bottom of the wind turbine foundation, using the foundation steel mesh as a natural grounding body.

[0017] Specifically, a flat steel pressure plate is provided above the extended end of the radial flat steel. One end of the graphite-based flexible grounding wire extends into the wind turbine foundation and is placed between the radial flat steel and the flat steel pressure plate. The flat steel pressure plate is connected to the radial flat steel by metal bolts and presses and fixes the graphite-based flexible grounding wire.

[0018] Specifically, it also includes waterproof adhesive and conductive adhesive. The wind turbine foundation is provided with an anti-corrosion coating. The first non-metallic conductive membrane is glued and fixed to the outside of the anti-corrosion coating and located below the frost line by waterproof adhesive. The overlapping section of the first non-metallic conductive membrane is glued and fixed by conductive adhesive. The first non-metallic conductive membrane is in contact with the backfill soil of the foundation pit and is used to conduct the lightning current to the ground.

[0019] Specifically, it also includes non-metallic fasteners. The second non-metallic conductive roll is bonded and fixed to the first non-metallic conductive roll by a conductive adhesive, and is pressed and connected to the graphite-based flexible grounding wire by a number of non-metallic fasteners.

[0020] Specifically, the first and second non-metallic conductive rolls are made of graphite paper, and their outer surfaces are roughened to form a honeycomb structure.

[0021] In particular, in geological environments with high resistivity, the contact area between the first and second non-metallic conductive rolls and the foundation soil is filled with a resistance-reducing agent or low-resistivity soil to increase the length of the graphite-based flexible grounding wire and increase the contact area between the graphite-based flexible grounding wire and the first and second non-metallic conductive rolls.

[0022] A construction method for an attached grounding grid for wind turbine foundations includes the following steps:

[0023] S1. When binding the wind turbine foundation reinforcement, an inner ring and an outer ring are arranged on the upper surface of the bottom reinforcement of the wind turbine foundation. The inner ring and the outer ring are connected by several radial flat steel welds and extend to the edge of the wind turbine foundation. The extended end of the radial flat steel is connected to one end of the graphite-based flexible grounding wire by pressing it with a flat steel pressure plate and then by metal bolts. The other end of the graphite-based flexible grounding wire is led out from the top of the wind turbine foundation steel formwork. Four lead-out flat steels are led out from the inner ring equipotential ring. The lead-out flat steels exceed the column by a certain height and are fixed.

[0024] S2. When pouring concrete for the wind turbine foundation, the vibrator must not come into direct contact with the inner and outer equipotential rings to avoid affecting the joints of the grounding body inside the wind turbine foundation.

[0025] S3. After the concrete pouring of the wind turbine foundation is completed, curing and demolding are carried out. An anti-corrosion coating is sprayed on the outer surface of the wind turbine foundation and allowed to dry. After the anti-corrosion coating is dry, the surface of the anti-corrosion coating is cleaned, a waterproof adhesive is applied, and a first non-metallic conductive membrane is pasted on the side of the wind turbine foundation below the frost line. When pasting, ensure that the membrane is undamaged. When overlapping the membrane, use conductive adhesive to bond the overlap position. The overlap length can ensure that the conductivity between the membranes is not affected.

[0026] S4. Cut a second non-metallic conductive roll to a suitable size, bond it to the graphite-based flexible grounding wire with conductive adhesive in the center and let it dry. Then, press the connection with non-metallic fasteners. Next, bond the second non-metallic conductive roll to the first non-metallic conductive roll on the side of the wind turbine foundation with conductive adhesive and let it dry. When bonding, ensure that the graphite-based flexible grounding wire is located between the first and second non-metallic conductive rolls. The size of the cut second non-metallic conductive roll is not less than the overlap length of the first non-metallic conductive roll.

[0027] S5. Backfilling and compaction of the wind turbine foundation pit. Backfill material is backfill soil. In environments with high resistivity, the contact area between the first non-metallic conductive roll and the foundation soil is filled with a resistance-reducing agent or low resistivity soil to increase the length of the graphite-based flexible grounding wire and increase the contact area between the graphite-based flexible grounding wire and the first and second non-metallic conductive rolls.

[0028] S6. The exposed parts of the four lead-out flat steels of the lead-out column are connected by annular galvanized flat steel to form a top equalizing ring, and are connected to the upper anchor plate through wires to form a complete wind turbine foundation grounding network.

[0029] The beneficial effects of this invention are:

[0030] The wind turbine foundation attached grounding grid proposed in this invention has a grounding electrode that, except for the portion of the flat steel lead-out column, is entirely encased in the foundation concrete. All grounding conductors and connecting fasteners in contact with the soil are made of non-metallic materials, providing excellent corrosion resistance. The non-metallic conductive roll is attached to the side surface of the wind turbine foundation, resulting in a large contact area with the soil and high efficiency in discharging lightning current into the ground. Furthermore, it is unaffected by subsequent earthwork construction around the foundation. This low-impedance grounding grid is easy to construct, durable, and ensures high construction quality, offering significant comprehensive benefits and promising application prospects. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the grounding grid structure of the present invention;

[0032] Figure 2 This is a schematic diagram of the connection node between the radial flat steel and the graphite-based flexible grounding wire of the present invention.

[0033] Figure 3 This is a schematic diagram of the connection node between the graphite-based flexible grounding wire and the second non-metallic conductive roll material according to the present invention.

[0034] Figure 4 This is a schematic diagram showing the connection between the first non-metallic conductive roll and the second non-metallic conductive roll of the present invention.

[0035] In the diagram: 1-Wind turbine foundation; 11-Anti-corrosion coating; 2-Grounding electrode; 21-Inner ring equalizing ring; 22-Outer ring equalizing ring; 23-Radial flat steel; 24-Lead-out flat steel; 3-Top equalizing ring; 4-Graphite-based flexible grounding wire; 41-Flat steel pressure plate; 42-Metal bolt; 5-First non-metallic conductive membrane; 6-Upper anchor plate; 7-Second non-metallic conductive membrane; 8-Waterproof adhesive; 9-Conductive adhesive; 10-Non-metallic fastener;

[0036] The following will describe in detail, with reference to the accompanying drawings, embodiments of the present invention. Detailed Implementation

[0037] The present invention will be further described below with reference to embodiments:

[0038] like Figures 1-4 As shown, a wind turbine foundation attached grounding grid includes:

[0039] Grounding electrode 2 is installed inside the wind turbine foundation 1;

[0040] The top equalizing ring 3 is installed on the top of the wind turbine foundation 1 and connected to the grounding body 2;

[0041] The graphite-based flexible grounding wire 4 is a grounding conductor led out from inside the wind turbine foundation 1, with one end connected to the grounding body 2 and the other end led out of the wind turbine foundation 1;

[0042] The first non-metallic conductive roll 5 is pasted around the wind turbine foundation 1 and reliably connected to the graphite-based flexible grounding wire 4;

[0043] The upper anchor plate 6 is set on the top of the wind turbine foundation 1 and connected to the top equalizing ring 3 through a wire;

[0044] The second non-metallic conductive roll 7 is pasted on the outside of the first non-metallic conductive roll 5 and the graphite-based flexible grounding wire 4 is fixed between the first non-metallic conductive roll 5 and the second non-metallic conductive roll 7.

[0045] The grounding electrode 2, the top equalizing ring 3, the graphite-based flexible grounding wire 4, the first non-metallic conductive roll 5, the second non-metallic conductive roll 7, together with the earth, form a lightning protection grounding system.

[0046] Reference Figure 1 The grounding body 2 includes an inner ring equalizing ring 21, an outer ring equalizing ring 22, radial flat steel 23, and lead-out flat steel 24. The inner ring equalizing ring 21 and the outer ring equalizing ring 22 are concentrically arranged at the bottom of the wind turbine foundation 1. Several radial flat steels 23 are welded between the inner ring equalizing ring 21 and the outer ring equalizing ring 22. The outer ring equalizing ring 22 extends to the edge of the wind turbine foundation 1 through the radial flat steel 23 and connects to the graphite-based flexible grounding wire 4, and is led out through the graphite-based flexible grounding wire 4. The inner ring equalizing ring 21 is led out through four lead-out flat steels 24 and connected to the top equalizing ring 3 of the wind turbine foundation 1.

[0047] The inner ring equalizing ring 21, the outer ring equalizing ring 22, and the radial flat steel 23 are spot welded to the foundation steel bars at the bottom of the wind turbine foundation 1, using the foundation steel mesh as a natural grounding body to increase conductivity.

[0048] The portion of the flat steel 24 exposed on the fan foundation 1 is hot-dip galvanized and connected by annular galvanized flat steel to form a top equalizing ring 3.

[0049] Reference Figure 2A flat steel pressure plate 41 is provided above the extended end of the radial flat steel 23. One end of the graphite-based flexible grounding wire 4 extends into the wind turbine foundation 1 and is placed between the radial flat steel 23 and the flat steel pressure plate 41. The flat steel pressure plate 41 is connected to the radial flat steel 23 by metal bolts 42 and presses and fixes the graphite-based flexible grounding wire 4, and the graphite-based flexible grounding wire 4 is led out.

[0050] Reference Figure 4 The wind turbine foundation attached grounding grid also includes a waterproof adhesive 8 and a conductive adhesive 9. The wind turbine foundation 1 is provided with an anti-corrosion coating 11, such as epoxy asphalt paint. The first non-metallic conductive roll 5 is pasted and fixed to the outside of the anti-corrosion coating 11 by the waterproof adhesive 8 and is located below the frost line. The overlapping section of the first non-metallic conductive roll 5 is pasted and fixed by the conductive adhesive 9. The first non-metallic conductive roll 5 is in contact with the backfill soil of the foundation pit and is used to conduct the lightning current to the ground.

[0051] Reference Figure 3 The wind turbine foundation attached grounding grid also includes non-metallic fasteners 10, which are made of corrosion-resistant materials such as plastic. The second non-metallic conductive roll 7 is bonded and fixed to the first non-metallic conductive roll 5 by conductive adhesive 9, and is pressed and connected to the graphite-based flexible grounding wire 4 by several non-metallic fasteners 10.

[0052] The first non-metallic conductive roll 5 and the second non-metallic conductive roll 7 are graphite paper. Their outer surfaces are roughened to form a honeycomb structure to increase the contact area and adsorption performance between the non-metallic conductive roll and water in the soil. Graphite paper is a paper-like composite roll material based on graphite. It is soft, flexible, and has good corrosion resistance and conductivity. It can adapt to various corrosive soil environments. When used as a grounding conductor, its contact area with the soil is much larger than that of conventional grounding wires.

[0053] In geological environments with high resistivity, the contact area between the first non-metallic conductive membrane 5 and the foundation soil is filled with a resistance-reducing agent or low-resistivity soil. The length of the graphite-based flexible grounding wire 4 can also be increased to enlarge the contact area between the graphite-based flexible grounding wire 4 and the first non-metallic conductive membrane 5 and the second non-metallic conductive membrane 7, thereby improving the conductivity of the grounding grid.

[0054] A construction method for an attached grounding grid for wind turbine foundations includes the following steps:

[0055] S1. When binding the reinforcing bars of the wind turbine foundation 1, an inner ring equalizing ring 21 and an outer ring equalizing ring 22 are arranged on the upper surface of the bottom reinforcing bars of the wind turbine foundation 1. The inner ring equalizing ring 21 and the outer ring equalizing ring 22 are connected by several radial flat steels 23 and extend to the edge of the wind turbine foundation 1. The extended end of the radial flat steels 23 is connected to one end of the graphite-based flexible grounding wire 4 by pressing it with a flat steel pressure plate 41 and then by metal bolts 42. The other end of the graphite-based flexible grounding wire 4 is led out from the top of the steel formwork of the wind turbine foundation 1. Four lead-out flat steels 24 are led out from the inner ring equalizing ring 21. The lead-out flat steels 24 extend beyond the column to a certain height and are fixed.

[0056] S2. When pouring concrete for the wind turbine foundation, the vibrator must not come into direct contact with the inner ring equalizing ring 21 and the outer ring equalizing ring 22 to avoid affecting the joints of the grounding body 2 inside the wind turbine foundation 1.

[0057] S3. After the concrete pouring of the wind turbine foundation is completed, curing and demolding are carried out. Anti-corrosion coating 11 (such as epoxy asphalt paint) is sprayed on the outer surface of the wind turbine foundation 1 and dried. After the anti-corrosion coating 11 is dried, the surface of the anti-corrosion coating 11 is cleaned, and waterproof adhesive 8 is applied. A first non-metallic conductive roll 5 is pasted on the side of the wind turbine foundation 1 below the frost line. When pasting, ensure that the roll is undamaged. When the roll is overlapped, the overlap position is bonded with conductive adhesive 9. The overlap length can ensure that the conductivity between the rolls is not affected.

[0058] S4. Cut the second non-metallic conductive roll 7 to a suitable size, bond it to the graphite-based flexible grounding wire 4 with conductive adhesive 9 in the middle and let it dry. Then, use non-metallic fasteners 10 (made of corrosion-resistant materials such as plastic) to tighten the connection. Next, bond the second non-metallic conductive roll 7 to the first non-metallic conductive roll 5 on the side of the wind turbine foundation 1 with conductive adhesive 9 and let it dry. When bonding, ensure that the graphite-based flexible grounding wire 4 is located between the first non-metallic conductive roll 5 and the second non-metallic conductive roll 7. The size of the cut second non-metallic conductive roll 7 is not less than the overlap length of the first non-metallic conductive roll 5.

[0059] S5. Backfilling and compaction of the foundation pit for the wind turbine: The backfill material shall be backfill soil (such as sand, clay, silt or small-particle gravel). Construction waste, rubble, large-particle gravel and other materials are strictly prohibited to avoid damage to the non-metallic conductive membrane. In environments with high resistivity, the contact area between the first non-metallic conductive membrane 5 and the second non-metallic conductive membrane 7 and the foundation soil shall be filled with a resistance-reducing agent or low-resistivity soil to increase the length of the graphite-based flexible grounding wire 4 and the contact area between the graphite-based flexible grounding wire 4 and the first non-metallic conductive membrane 5 and the second non-metallic conductive membrane 7.

[0060] S6. The exposed portions of the four lead-out flat steels 24 of the lead-out column are connected by annular galvanized flat steel to form a top equalizing ring 3, and are connected to the upper anchor plate 6 through wires to form a complete wind turbine foundation grounding network.

[0061] The wind turbine foundation attached grounding grid proposed in this invention, except for the part of the grounding electrode led out by the flat steel 24 leading out of the column, is completely wrapped in the foundation concrete. All grounding conductors and connecting fasteners in contact with the soil are made of non-metallic materials, which have good corrosion resistance. The non-metallic conductive roll is attached to the surface of the wind turbine foundation 1, with a large contact area with the soil, resulting in high efficiency of lightning current discharge to the ground. It is also unaffected by the subsequent earthwork construction around the foundation. It is a low-impedance grounding grid that is easy to construct, durable, and easy to ensure construction quality, with significant comprehensive benefits and good application prospects.

[0062] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0063] Furthermore, 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 at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0065] The present invention has been described above by way of example. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or direct application to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A wind turbine foundation-attached grounding grid, characterized in that, include: Grounding electrode (2) is installed inside the wind turbine foundation (1); The top equalizing ring (3) is set on the top of the wind turbine foundation (1) and connected to the grounding body (2); A graphite-based flexible grounding wire (4) is connected at one end to the grounding body (2) and at the other end to the wind turbine foundation (1); The first non-metallic conductive roll (5) is pasted around the wind turbine foundation (1) and reliably connected to the graphite-based flexible grounding wire (4); The upper anchor plate (6) is set on the top of the wind turbine foundation (1) and connected to the top equalizing ring (3) through a wire; The second non-metallic conductive roll (7) is pasted on the outside of the first non-metallic conductive roll (5) and the graphite-based flexible grounding wire (4) is fixed between the first non-metallic conductive roll (5) and the second non-metallic conductive roll (7); The grounding electrode (2), the top equalizing ring (3), the graphite-based flexible grounding wire (4), the first non-metallic conductive roll (5), the second non-metallic conductive roll (7) together with the earth form a lightning protection grounding system.

2. The wind turbine foundation attached grounding grid according to claim 1, characterized in that, The grounding body (2) includes an inner ring equalizing ring (21), an outer ring equalizing ring (22), radial flat steel (23), and lead-out flat steel (24). The inner ring equalizing ring (21) and the outer ring equalizing ring (22) are concentrically set at the bottom of the wind turbine foundation (1). Several radial flat steels (23) are welded between the inner ring equalizing ring (21) and the outer ring equalizing ring (22). The outer ring equalizing ring (22) extends to the edge of the wind turbine foundation (1) through the radial flat steel (23) and connects to the graphite-based flexible grounding wire (4), and is led out by the graphite-based flexible grounding wire. The inner ring equalizing ring (21) is led out of the wind turbine foundation (1) column and connected to the top equalizing ring (3) through four lead-out flat steels (24).

3. The wind turbine foundation attached grounding grid according to claim 2, characterized in that, The portion of the flat steel (24) exposed on the fan foundation (1) is hot-dip galvanized and connected by annular galvanized flat steel to form a top equalizing ring (3).

4. The wind turbine foundation attached grounding grid according to claim 3, characterized in that, The inner ring equalizing ring (21), the outer ring equalizing ring (22), and the radial flat steel (23) are spot welded to the foundation steel bars at the bottom of the wind turbine foundation (1), and the foundation steel mesh is used as a natural grounding body.

5. The wind turbine foundation attached grounding grid according to claim 4, characterized in that, A flat steel plate (41) is provided above the extended end of the radial flat steel (23). One end of the graphite-based flexible grounding wire (4) extends into the wind turbine foundation (1) and is placed between the radial flat steel (23) and the flat steel plate (41). The flat steel plate (41) is connected to the radial flat steel (23) by metal bolts (42) and presses and fixes the graphite-based flexible grounding wire (4).

6. The wind turbine foundation attached grounding grid according to claim 5, characterized in that, It also includes a waterproof adhesive (8) and a conductive adhesive (9). The wind turbine foundation (1) is provided with an anti-corrosion coating (11) on the outside. The first non-metallic conductive roll (5) is pasted and fixed to the outside of the anti-corrosion coating (11) by the waterproof adhesive (8) and is located below the frost line. The overlapping section of the first non-metallic conductive roll (5) is pasted and fixed by the conductive adhesive (9). The first non-metallic conductive roll (5) is in contact with the backfill soil of the foundation pit and is used to conduct the lightning current to the ground.

7. A wind turbine foundation attached grounding grid according to claim 6, characterized in that, It also includes non-metallic fasteners (10), the second non-metallic conductive roll (7) is bonded and fixed to the first non-metallic conductive roll (5) by conductive adhesive (9), and is pressed and connected to the graphite-based flexible grounding wire (4) by several non-metallic fasteners (10).

8. The wind turbine foundation attached grounding grid according to claim 7, characterized in that, The first non-metallic conductive roll (5) and the second non-metallic conductive roll (7) are graphite paper, and their outer surfaces are roughened to form a honeycomb structure network.

9. A wind turbine foundation attached grounding grid according to claim 8, characterized in that, In geological environments with high resistivity, the contact area between the first non-metallic conductive roll (5) and the second non-metallic conductive roll (7) and the foundation soil is filled with a resistance-reducing agent or low-resistivity soil to increase the length of the graphite-based flexible grounding wire (4) and increase the contact area between the graphite-based flexible grounding wire (4) and the first non-metallic conductive roll (5) and the second non-metallic conductive roll (7).

10. A construction method for an attached grounding grid for a wind turbine foundation according to claim 9, characterized in that, Includes the following steps: S1. When binding the reinforcing bars of the wind turbine foundation (1), an inner ring equalizing ring (21) and an outer ring equalizing ring (22) are arranged on the upper surface of the bottom reinforcing bars of the wind turbine foundation (1). The inner ring equalizing ring (21) and the outer ring equalizing ring (22) are connected by several radial flat steels (23) and extend to the edge of the wind turbine foundation (1). The extended end of the radial flat steels (23) is pressed with one end of the graphite-based flexible grounding wire (4) by a flat steel pressure plate (41) and then connected by a metal bolt (42). The other end of the graphite-based flexible grounding wire (4) is led out from the top of the steel template of the wind turbine foundation (1). Four lead-out flat steels (24) are led out from the inner ring equalizing ring (21). The lead-out flat steels (24) extend beyond the column to a certain height and are fixed. S2. When pouring concrete for the wind turbine foundation, the vibrator must not come into direct contact with the inner ring equalizing ring (21) and the outer ring equalizing ring (22) to avoid affecting the joints of the grounding body (2) inside the wind turbine foundation (1). S3. After the concrete pouring of the wind turbine foundation is completed, it is cured and the formwork is removed. The anti-corrosion coating (11) is sprayed on the outer surface of the wind turbine foundation (1) and dried. After the anti-corrosion coating (11) is dried, the surface of the anti-corrosion coating (11) is cleaned and waterproof adhesive (8) is applied. A first non-metallic conductive roll (5) is pasted on the side of the wind turbine foundation (1) below the frost line. When pasting, ensure that the roll is undamaged. When the roll is overlapped, the overlap position is bonded with conductive adhesive (9). The overlap length can ensure that the conductivity between the rolls is not affected. S4. Cut a second non-metallic conductive roll (7) to a suitable size, bond it to the graphite-based flexible grounding wire (4) with conductive adhesive (9) in the middle and let it dry. Then, press it tightly with non-metallic fasteners (10). Next, bond the second non-metallic conductive roll (7) to the first non-metallic conductive roll (5) on the side of the wind turbine foundation (1) with conductive adhesive (9) and let it dry. When bonding, ensure that the graphite-based flexible grounding wire (4) is located between the first non-metallic conductive roll (5) and the second non-metallic conductive roll (7). The size of the cut second non-metallic conductive roll (7) is not less than the overlap length of the first non-metallic conductive roll (5). S5, wind turbine foundation (1) backfilling and compaction of foundation pit. Backfill material is backfill soil. For environments with high resistivity, the contact parts of the first non-metallic conductive roll (5) and the second non-metallic conductive roll (7) with the foundation soil are filled with resistance reducing agent or low resistivity soil to increase the length of the graphite-based flexible grounding wire (4) and increase the contact area between the graphite-based flexible grounding wire (4) and the first non-metallic conductive roll (5) and the second non-metallic conductive roll (7). S6. The exposed parts of the four lead-out flat steels (24) of the lead-out column are connected by annular galvanized flat steel to form a top equalizing ring (3), and are connected to the upper anchor plate (6) through wires to form a complete wind turbine foundation grounding network.

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