Pile foundation external application device, grounding pile foundation and grounding system

Abstract

The invention discloses a pile foundation external application device, a grounding pile foundation and a grounding system, the pile foundation external application device is cylindrical and comprises a base body layer, a transition layer and an external coating layer, the transition layer is wrapped by the external coating layer, the base body layer is wrapped by the transition layer, and the resistance of the transition layer is in index attenuation distribution from the resistivity of the base body layer to the resistivity of the external coating layer. Therefore, the substrate layer, the transition layer and the outer coating layer form a gradient conductive structure, the resistivity of the pile foundation external application device is in gradient distribution, the interface potential barrier is effectively inhibited, and the pile foundation grounding resistance is effectively reduced after the pile foundation external application device is externally applied to a grounding pile foundation, so that the grounding resistance of a grounding system is reduced, and the diversion performance of the grounding system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of lightning protection and grounding technology, and more specifically, to a pile foundation external application device, a grounding pile foundation, and a grounding system. Background Art

[0002] In power systems, the performance of the grounding system is crucial to ensuring the safe and stable operation of equipment. Reducing grounding resistance and improving grounding conductivity have become key requirements.

[0003] When handling high-amplitude lightning currents, traditional galvanized steel grounding electrodes are prone to melting due to local overheating, rendering the grounding system ineffective. Furthermore, when high-frequency lightning currents pass through, the skin effect causes uneven current distribution within the grounding electrode, significantly increasing transient impedance and severely weakening overvoltage suppression capabilities.

[0004] Therefore, how to design a material device for reducing grounding resistance to reduce the grounding resistance of the grounding system, improve the current conduction performance of the grounding system, and provide strong support for the safe, stable and efficient operation of the power system is an issue that needs attention. Summary of the Invention

[0005] In view of the above problems, the present application provides a pile foundation external application device, a grounding pile foundation, and a grounding system to reduce the grounding resistance of the grounding system and improve the conductivity performance of the grounding system.

[0006] In order to achieve the above objectives, the following specific plans are proposed:

[0007] A pile foundation external coating device, the pile foundation external coating device is cylindrical and comprises a base layer, a transition layer and an outer coating layer;

[0008] The outer covering layer wraps the transition layer, and the transition layer wraps the base layer;

[0009] The resistance of the transition layer satisfies the following formula:

[0010]

[0011] in, is the resistance of the transition layer, is the radial coordinate variable, is the inner radius of the transition layer, is the outer radius of the transition layer, is an exponentially decaying distribution function that transitions from the resistivity of the substrate layer to the resistivity of the outer coating layer.

[0012] Optionally, the base layer comprises high silicon chromium iron alloy;

[0013] The high-silicon ferrochromium alloy has a silicon content of 3 wt%-4 wt%, a chromium content of 12 wt%-13 wt%, and a carbon content of 2 wt%-3 wt%.

[0014] Optionally, the transition layer is a gradient ferroferric oxide semiconductor layer, and the gradient ferroferric oxide semiconductor layer comprises an outer layer and an inner layer;

[0015] The resistivity distribution from the inner layer to the outer layer is from 10 -2 Ω•cm to 10 2 Continuous distribution of Ω•cm.

[0016] Optionally, the inner layer is composed of pure ferrosoferric oxide, and the outer layer is composed of ferrous aluminate.

[0017] Optionally, the saturation magnetization of the inner layer is greater than 80emu / g, and the Curie temperature of the inner layer is greater than 580°C.

[0018] Optionally, the outer coating comprises a graphene film, the thickness of the graphene film is 2nm-5nm, and the in-plane conductivity of the graphene film is greater than 10 7 S / m.

[0019] Optionally, a nickel-copper composite layer is deposited on the surface of the gradient ferroferric oxide semiconductor layer, so that when the copper of the nickel-copper composite layer diffuses to the ferroferric oxide grain boundary to reduce the diffusion activation energy, the nickel of the nickel-copper composite layer and the graphene form nickel carbide for improving the bonding strength between the transition layer and the outer coating.

[0020] Optionally, the outer coating further includes a buffer layer, and the buffer layer is used to reduce the interface defect density between the transition layer and the outer coating.

[0021] A grounding pile foundation is provided, wherein the pile foundation external application device as described above is applied externally on the grounding pile foundation in a spirally wound manner.

[0022] A grounding system comprising a connecting conductor and a plurality of grounding piles as described above, wherein the grounding piles comprise lead-out conductors;

[0023] Each of the grounding piles forms a cage structure, and the connecting wire connects the lead-out wires of each of the grounding columns according to the cage structure.

[0024] By utilizing the above-described technical solution, the pile foundation external coating device of the present application is cylindrical and includes a base layer, a transition layer, and an outer coating. The outer coating wraps the transition layer, which in turn wraps the base layer. The resistance of the transition layer exhibits an exponentially decaying distribution, transitioning from the resistivity of the base layer to the resistivity of the outer coating. Thus, the base layer, transition layer, and outer coating form a gradient conductive structure. The resistivity of the pile foundation external coating device exhibits a gradient distribution, effectively suppressing interfacial potential barriers. When the pile foundation external coating device is applied to a grounded pile foundation, it significantly reduces the grounding resistance of the pile foundation, thereby reducing the grounding resistance of the grounding system and improving the current conduction performance of the grounding system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0026] Figure 1 A schematic structural diagram of a pile foundation external application device provided in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of a grounding system implemented based on a pile foundation external application device provided in an embodiment of the present application;

[0028] Figure 3 A schematic diagram of a traditional grounding system provided in an embodiment of the present application;

[0029] Figure 4 A schematic diagram of a flow chart for implementing grounding system simulation calculations provided in an embodiment of the present application;

[0030] Figure 5 A schematic diagram of the amplitude of an impulse current provided in an embodiment of the present application;

[0031] Figure 6 A graph showing the change in the impact resistance of a conventional grounding system provided in an embodiment of the present application;

[0032] Figure 7 This is a graph showing the change in impact resistance of a grounding system implemented based on a pile foundation external application device according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] Figure 1 An optional structure of the pile foundation external application device provided in the embodiment of the present application, such as Figure 1 As shown, the pile foundation external coating device can be cylindrical. The pile foundation external coating device can include: a base layer, a transition layer and an outer covering layer.

[0035] The outer covering layer wraps the transition layer, and the transition layer wraps the base layer.

[0036] Understandably, the stable cylindrical structure and three-layer wrapping design enable the pile foundation external application device to maintain excellent performance in a variety of environments. Whether in areas with complex soil conditions or under external forces, it can maintain its structural integrity and conductivity, ensuring the stable operation of the grounding system and reducing grounding performance fluctuations caused by environmental factors.

[0037] The resistance of the transition layer satisfies the following formula:

[0038]

[0039] in, is the resistance of the transition layer, is the radial coordinate variable, is the inner radius of the transition layer, is the outer radius of the transition layer, This is the exponentially decaying distribution function for the transition from the resistivity of the base layer to the resistivity of the outer layer. This exponentially decaying resistivity distribution reduces the contact resistance between the device and the soil. This exponential decay allows the current to better adapt to the soil's conductivity as it diffuses from the device to the soil, dispersing it more evenly and expanding its diffusion range. This effectively reduces grounding resistance and improves the overall performance of the grounding system. This exponentially decaying resistivity distribution allows the device to better adapt to soils of varying resistivity.

[0040] In high-resistivity soil, the exponentially decaying resistivity distribution helps the current break through the high-resistance areas of the soil and find a path that is more conducive to diffusion; in low-resistivity soil, it can also ensure uniform current diffusion, avoiding the occurrence of local excessive current, and improving the adaptability of the grounding system in different soil environments.

[0041] It is understandable that the cylindrical pile foundation external coating device makes the current conduction more uniform in all directions. When current is introduced, there will be no current concentration or poor conduction due to the irregular shape. The layered structure of the base layer, transition layer and outer layer, as well as the exponential decay distribution function of the resistivity transition from the base layer to the outer layer, creates a smooth conductive gradient, allowing the current to smoothly conduct along this gradient from the base layer with lower resistivity to the outer layer, reducing the obstacles to current transmission between layers and ensuring efficient current conduction.

[0042] In terms of anti-corrosion performance, the structure of the outer covering layer wrapping the transition layer and the transition layer wrapping the base layer provides multiple protections for the base layer. The outer covering layer and the transition layer can be made of materials with good anti-corrosion properties, such as graphene, which can effectively prevent the erosion of the base layer by moisture, acid and alkali substances in the soil, thereby extending the service life of the pile foundation external application device and ensuring the long-term and stable operation of the grounding system.

[0043] Based on the three-layer structure of the pile foundation external coating device and the gradient resistivity distribution, the first interlayer contact resistance between the base layer and the transition layer can be obtained as:

[0044]

[0045] in, is the first interlayer contact resistance, is the effective resistivity of the material of the transition layer at the first interlayer surface between the base layer and the transition layer, is the effective contact radius between the base layer and the transition layer, is the interface state density of the first interlayer surface, is the tunneling distance of the first interlayer surface.

[0046] The second interlayer contact resistance between the transition layer and the outer cover is:

[0047]

[0048] in, is the second inter-layer contact resistance, is the composite value of the resistivity of the material of the transition layer and the resistivity of the material of the outer covering layer, is the interface state density at the second interlayer between the transition layer and the outer coating, is the tunneling distance of the second interlayer surface.

[0049] When the pile foundation external application device is in contact with the target soil, the total grounding resistance of the pile foundation external application device is:

[0050]

[0051] in, is the total grounding resistance, is the resistance of the substrate layer itself, is the first optimal thickness ratio determined by finite element simulation of the effective contact area of the first interlayer surface, is the second optimal thickness ratio determined by finite element simulation of the effective contact area of the second interlayer surface, is the stray resistance of the target soil.

[0052] The pile foundation external coating device provided in this embodiment is cylindrical and includes a base layer, a transition layer, and an outer coating. The outer coating wraps the transition layer, which in turn wraps the base layer. The resistance of the transition layer exhibits an exponentially decaying distribution, transitioning from the resistivity of the base layer to the resistivity of the outer coating. Thus, the base layer, transition layer, and outer coating form a gradient conductive structure. The resistivity of the pile foundation external coating device exhibits a gradient distribution, effectively suppressing interfacial potential barriers. When applied to a grounded pile foundation, the pile foundation external coating device significantly reduces the grounding resistance of the pile foundation, thereby reducing the grounding resistance of the grounding system and improving the grounding system's conductivity.

[0053] In some embodiments of the present application, the substrate layer mentioned in the above embodiments is further described. The substrate layer may include a high-silicon ferrochrome alloy having a silicon content of 3 wt%-4 wt%, a chromium content of 12 wt%-13 wt%, and a carbon content of 2 wt%-3 wt%. This alloy can promote carbide formation to enhance hardness while preventing embrittlement of the substrate caused by excessive carbon.

[0054] Furthermore, 0.5-1.0 wt% nickel can be added to improve the ductility of the high silicon ferrochrome alloy and avoid brittle fracture caused by high silicon.

[0055] It is understandable that silicon can improve the electrical conductivity of high-silicon ferrochrome alloy. A silicon content of 3 wt%-4 wt% optimizes the electron conduction path while ensuring other properties of the alloy, making the high-silicon ferrochrome alloy have good electrical conductivity and enabling the current to be conducted quickly in the matrix layer, providing an efficient conductive foundation for the grounding system, reducing losses during current transmission, lowering grounding resistance, and improving grounding conductivity.

[0056] Chromium is a key element in improving the alloy's corrosion resistance. A chromium content of 12-13 wt% forms a dense oxide film on the alloy surface. This film effectively blocks external corrosive media, such as soil moisture and acids and bases, from contacting the alloy matrix. This significantly enhances the matrix's corrosion resistance, extending the life of the grounding device and ensuring the long-term stable operation of the grounding system.

[0057] Controlling the carbon content between 2 wt% and 3 wt% promotes the formation of carbides. The presence of carbides effectively enhances the alloy's hardness and strength, preventing brittle fracture caused by high silicon content. This allows the matrix layer to maintain structural integrity when subjected to external forces, such as soil compression and impact, preventing deformation and fracture. This ensures the physical stability of the grounding device and, consequently, the proper functioning of the grounding system.

[0058] The reasonable combination of the three elements of silicon, chromium and carbon enables the high-silicon ferrochromium alloy to achieve a good balance between conductivity, corrosion resistance and mechanical strength, avoiding the adverse effects of excessively high or low content of a single element on the alloy performance, ensuring that the matrix layer can fully play its role in the grounding device, and providing a reliable material foundation for the stable operation of the entire grounding system.

[0059] Specifically, in the preparation process of the matrix layer, during the raw material processing, copper slag, chromite powder, and a carbonaceous reducing agent (such as coke) can be mixed and crushed to a size of less than 200 mesh. A binder (such as starch) is added to form pellets. During the sintering and smelting process, spark plasma sintering can be used at a temperature of 1200°C and a pressure of 50 MPa to control the grain size to less than 10 μm to improve the strength and toughness of the matrix layer.

[0060] In some embodiments of the present application, the transition layer mentioned in the above embodiments is further introduced, and the transition layer is a gradient ferrosoferric oxide semiconductor layer.

[0061] It can be understood that the gradient ferroferric oxide semiconductor layer of the transition layer has a gradient resistivity change, which realizes a smooth transition from the base layer to the outer covering layer, effectively reduces the contact resistance between the layers, and avoids the current transmission obstruction caused by the sudden change of resistivity. When the current is conducted from the base layer to the transition layer, it can smoothly diffuse to the low resistivity area according to its gradient change characteristics, thereby improving the overall conductive efficiency and reducing the grounding resistance. In the event of a large current shock such as a lightning current, this smooth conductive transition can ensure that the current passes through the grounding device quickly and stably, reducing energy loss.

[0062] Ferroferric oxide is magnetic and can absorb high-frequency components through the magnetic loss mechanism when lightning current strikes. The structure of the gradient ferroferric oxide semiconductor layer further enhances this characteristic, enabling the grounding device to better absorb and suppress the high-frequency part of the lightning current. It not only reduces the impact impedance, but also reduces the risk of damage to equipment caused by overvoltage generated by lightning strikes, thereby improving the lightning protection performance of the grounding system.

[0063] The gradient ferroferric oxide semiconductor layer acts as a barrier, preventing corrosive media from eroding the base layer. Its relatively dense structure slows the ingress of moisture, acids, and bases, thereby extending the lifespan of the grounding system. The gradient ferroferric oxide semiconductor layer, combined with the outer coating, forms a multi-layered anti-corrosion defense, ensuring long-term stable operation of the grounding system in harsh environments.

[0064] The gradient ferrosoferric oxide semiconductor layer may include an outer layer and an inner layer.

[0065] The resistivity distribution from the inner layer to the outer layer can be from 10 -2 Ω•cm to 10 2 Continuous distribution of Ω•cm.

[0066] It can be understood that the low resistivity of the inner layer (10 -2 Ω•cm) to the outer layer with high resistivity (10 2 The continuous distribution of resistivity (Ω•cm) creates a smooth conductive gradient. When current flows from the low-resistance base layer to the high-resistance outer layer, this gradual resistivity gradient guides the current to spread evenly, preventing current concentration in localized areas and reducing losses during current transmission. For example, at the moment of a lightning strike, the lightning current can pass through the transition layer more orderly, reducing energy reflection caused by sudden resistance changes and improving the conductive efficiency of the grounding system.

[0067] In a high-frequency current environment, regions with different resistivity exhibit different response characteristics to electromagnetic interference. The inner, low-resistivity region quickly guides high-frequency current, while the outer, high-resistivity region inhibits further spread of high-frequency current, acting similarly to an electromagnetic shield. The inner and outer layer structure helps reduce the electromagnetic interference of the grounding device on surrounding electronic equipment, while also improving its own resistance to external electromagnetic interference, ensuring the stable operation of the power system. Furthermore, when subjected to a surge current, the inner and outer layer structure automatically adjusts the current distribution based on the current's magnitude and frequency. Smaller surge currents are rapidly discharged primarily through the inner, low-resistance region, while larger surge currents, after passing through the inner layer, gradually diffuse through the outer, high-resistance region, effectively reducing the instantaneous impact of the surge current on equipment and improving the surge tolerance of the grounding system.

[0068] The inner layer may be made of pure ferrosoferric oxide, have a saturation magnetization greater than 80 emu / g, and a Curie temperature greater than 580° C. The outer layer may be made of ferrous metaaluminate.

[0069] Understandably, the inner layer of pure ferroferric oxide has a saturation magnetization greater than 80 emu / g and a Curie temperature greater than 580°C. During a lightning strike, this high saturation magnetization enables the inner layer to more effectively absorb the high-frequency components of the lightning current through magnetic loss mechanisms. Meanwhile, the high Curie temperature ensures that the magnetic properties and related properties of ferroferric oxide remain stable even under the transient high temperatures of the lightning current, preventing it from losing its ability to absorb high-frequency currents due to excessive temperatures. This helps reduce impulse impedance, minimize damage to equipment caused by lightning strikes, and enhance the lightning protection effectiveness of the grounding system.

[0070] The resistivity of the inner layer of pure ferroferric oxide is relatively low ( ), providing an excellent conduction path for current. The outer layer of ferrous metaaluminate has a high resistivity (~10²Ω·cm), which, while maintaining a certain degree of conductivity, forms a gradient conductive structure with the inner layer. This structure optimizes the conduction of current from the inner layer to the outer layer, ensuring a more even current distribution, avoiding current concentration, reducing ground resistance, and improving grounding conductivity.

[0071] The outer layer of ferrous aluminate acts as a protective layer, reducing the erosion of corrosive substances on the inner layer of pure ferroferric oxide and the base layer. Its structure and composition prevent moisture, acids, and bases from coming into direct contact with the inner and base layers, extending the life of the grounding device and ensuring the long-term stable operation of the grounding system.

[0072] Specifically, in the preparation process of the transition layer, plasma assisted oxidation can be used: at 400 ° C, 10 -2 In an oxygen atmosphere of 104 Pa, pulsed laser oxidation (power density 104 W / cm², pulse width 100 ns) was performed, with a controlled oxidation rate of 0.2 μm / h and a thickness accuracy of ±3%. Magnetron sputtering was then used to pre-deposit a 50 nm iron nanolayer onto the substrate surface, improving oxidation uniformity and reducing thickness fluctuations (compared to ±15% in conventional processes).

[0073] In some embodiments of the present application, the outer coating layer mentioned in the above embodiment is introduced. The outer coating layer may include a graphene film. The thickness of the graphene film may be 2nm-5nm. The in-plane conductivity of the graphene film is greater than 10 7 S / m.

[0074] It is understandable that the graphene film is extremely thin but has in-plane conductivity Its high conductivity provides an extremely efficient conduction path for current. In a grounding system, when current reaches the outer coating, the graphene film allows the current to spread quickly and evenly within its plane, significantly reducing contact resistance. Its excellent conductivity further reduces grounding resistance, allowing the grounding device to more quickly conduct lightning or fault currents to the earth, improving grounding conductivity, reducing overvoltage and other problems caused by poor current flow, and ensuring the safety of power equipment.

[0075] Graphene membranes offer excellent chemical stability and a dense structure. Despite their thin thickness of 2-5nm, they effectively isolate corrosive substances from the outside world, such as moisture, oxygen, and acid and alkali ions in the soil. This effectively prevents these substances from chemically reacting with the inner layer material, thereby slowing the corrosion rate of the inner layer material, extending the service life of the grounding device and ensuring the long-term stable operation of the grounding system.

[0076] High currents flowing through grounding devices generate heat. Graphene has excellent thermal conductivity. When current flows through the graphene film, the generated heat is quickly conducted and dissipated, preventing local overheating that could degrade or damage the grounding device. This is crucial for maintaining the proper functioning of the grounding device under high current conditions, such as lightning strikes, and further ensures the reliability of the grounding system.

[0077] Based on this, a nickel-copper composite layer can be deposited on the surface of the gradient ferroferric oxide semiconductor layer. When the copper in the nickel-copper composite layer diffuses to the ferroferric oxide grain boundary to reduce the diffusion activation energy, the nickel in the nickel-copper composite layer and the graphene form nickel carbide to enhance the bonding strength between the transition layer and the outer coating. Specifically, it can be prepared by hot isostatic pressing process. The hot isostatic pressing process temperature is 300℃, pressure is 5MPa, time is 30min, interface shear strength is >60MPa, contact resistance is <10 -6 Ω·cm.

[0078] It is understood that in the nickel-copper composite layer, copper diffuses into the ferroferric oxide grain boundaries, reducing the diffusion activation energy and promoting atomic diffusion and interpenetration between the two materials, resulting in a tight bond between the ferroferric oxide semiconductor layer and the nickel-copper composite layer. Simultaneously, nickel and graphene form nickel carbide, establishing a strong chemical bond between the transition layer and the outer coating. This significantly enhances the bonding strength between the transition layer and the outer coating, preventing delamination and shedding between the layers during use, ensuring a stable grounding structure and maintaining good grounding performance.

[0079] Copper diffuses into the ferroferric oxide grain boundaries, changing the electronic structure there, reducing resistance to electron transmission and optimizing the electron transmission path within the transition layer. Nickel carbide, formed by nickel and graphene, creates an efficient electron conduction bridge between the transition layer and the overcoat, enabling electrons to transfer more smoothly between layers. This helps reduce interlayer contact resistance, further improving the conductivity of the grounding system and ensuring rapid and stable current flow through the grounding device.

[0080] The nickel-copper composite layer itself possesses a certain degree of corrosion resistance, providing additional protection for the gradient ferroferric oxide semiconductor layer. Copper diffusion into the ferroferric oxide grain boundaries enhances the structural stability of the ferroferric oxide, making it more resistant to external corrosive media. Simultaneously, the nickel carbide formed by nickel and graphene strengthens the bond between the overcoat and transition layer, preventing the intrusion of corrosive media, extending the service life of the grounding device and ensuring the long-term stable operation of the grounding system.

[0081] In addition, the outer coating layer may further include a buffer layer, which may be used to reduce the interface defect density between the transition layer and the outer coating layer.

[0082] Specifically, the outer coating can be prepared by plasma enhanced chemical vapor deposition. As the gas source, graphene is grown at 400℃ to avoid High temperature phase change (>600℃ decomposition into ), and then introduced two layers of hexagonal boron nitride (h-BN) as a buffer layer to reduce the interface defect density to Below, the electron mobility is increased to .

[0083] It is understandable that due to the difference in material properties between the transition layer and the outer coating, direct contact is prone to produce many interface defects, affecting the grounding performance. The presence of two layers of hexagonal boron nitride buffer layer can effectively fill these potential defects. The atomic structure of hexagonal boron nitride can form a good match with the atoms of the transition layer and the outer coating, reducing the lattice mismatch and reducing the interface defect density to 10 10 cm -2 The following provides a more stable path for current transmission, reduces contact resistance, and improves the conductivity of the grounding system.

[0084] Hexagonal boron nitride (HBN) has a unique crystal structure and high electron mobility. Introducing it as a buffer layer between the transition layer and the overcoat layer allows for smoother electron transfer between layers, helping to improve overall electron mobility. The electron mobility in the overcoat graphene layer has been raised to >2500 cm² / (V·s). When lightning or fault currents pass through, electrons conduct more efficiently, quickly conducting the current to the ground, reducing energy loss and overvoltage.

[0085] In actual applications, the grounding device will be subjected to external forces such as soil pressure and vibration. The buffer layer can effectively prevent the transition layer from separating from the outer cover, maintain the structural stability of the grounding device, and ensure long-term reliable grounding performance.

[0086] In the following embodiments, a grounding pile foundation is provided, and the grounding pile foundation can be externally coated with the pile foundation external coating device mentioned in the above embodiments.

[0087] refer to Figure 2 The pile foundation external application device can be applied on the grounded pile foundation in a spiral winding manner.

[0088] Understandably, the spiral winding method maximizes the contact area between the pile foundation external application device and the grounding pile foundation. Compared to other simpler attachment methods, the spiral shape increases the number of contact points and contact length between the two, ensuring a close connection between the external application device and the grounding pile foundation. This facilitates efficient current conduction between the two, reduces contact resistance, and thus improves the conductivity of the grounding system, allowing lightning or fault current to diffuse more smoothly from the grounding pile foundation through the external application device and into the surrounding soil.

[0089] Furthermore, the unique spiral winding structure provides diverse diffusion paths for current. As current flows from the grounding pile to the external application device, it diffuses along the spiral path over a wider area. This multidirectional diffusion method distributes current more evenly in the soil, preventing current concentration in localized areas. This effectively reduces grounding resistance and enhances the stability and reliability of the grounding system.

[0090] The spiral winding method gives the entire structure greater mechanical stability. The external application device is tightly wrapped around the ground pile foundation, which can better disperse stress when facing soil compression, vibration, or other external forces, preventing displacement and deformation of the ground pile foundation. This helps maintain the structural integrity of the grounding system and ensures that the grounding performance is not disturbed by external factors.

[0091] In some of the following embodiments, a grounding system is provided. The grounding system may include a connecting wire and a plurality of grounding piles mentioned in the above embodiments.

[0092] refer to Figure 2 The number of grounding piles can be 4, and the grounding piles can include lead wires. Each grounding pile can form a cage structure, and the connecting wires connect the lead wires of each grounding column according to the cage structure.

[0093] Next, we can respectively Figure 2 The grounding system shown and Figure 3 The grounding system shown in the figure (each grounding pile is not wrapped with a pile foundation external device) is simulated for current impulse to compare the impact grounding resistance of the two. The simulation process is as follows Figure 4 As shown, this may include:

[0094] Step S110: Obtain component parameters and topology parameters of the grounding system.

[0095] Specifically, the component parameters of the grounding system may include size parameters and material parameters of each component.

[0096] Examples of component parameters include ground pile height, ground pile (if cylindrical) radius, ground pile material, ground pile material conductivity, vertical ground body height, vertical ground body radius, vertical ground body material, vertical ground body material conductivity, horizontal ground body shape, horizontal ground body size, horizontal ground body material, horizontal ground body material conductivity, ground down conductor length, and ground down conductor burial depth. Figure 2 The component parameters of the grounding system shown may also include base layer parameters, transition layer parameters and outer covering layer parameters.

[0097] The topology parameters may include the relative position relationship between various components of the grounding system and the connection relationship between various components.

[0098] Step S120: construct an environmental simulation model of the grounding system according to component parameters and topology parameters, as well as environmental parameters of the grounding system.

[0099] The environmental simulation model may include a soil environment layer and a grounding system mechanism simulation model.

[0100] Step S130: determining an impact current for impacting the mechanism simulation model based on a contact area between the soil environment layer and the mechanism simulation model.

[0101] The contact area between the soil environment layer and the mechanism simulation model may include the contact area between the grounded pile foundation and the surrounding soil. Figure 2 The contact area of the grounding system shown may also include the contact area between the spiral wire and the soil environment layer.

[0102] In addition, the inrush current can be determined by customizing the inrush current peak value, peak time, and half-peak time.

[0103] Step S140 : applying an impulse current to the mechanism simulation model, and calculating the impulse grounding resistance of the mechanism simulation model under the impulse current.

[0104] Specifically, examples such as Figure 5A lightning impulse current of 8 / 20μs and an amplitude of 1kA impacts the mechanism simulation model. The mechanism simulation model calculates the current conduction capacity based on its own component parameters and topological structure parameters, and calculates the impulse grounding resistance under the impact of the impulse current in combination with the maximum ground potential rise near the mechanism simulation model.

[0105] For Figure 3 The grounding system shown in Figure 5 Under the impact current shown, the following can be obtained: Figure 6 The impulse grounding resistance shown; for Figure 2 The grounding system shown in Figure 5 Under the impact current shown, the following can be obtained: Figure 7 The impulse grounding resistance is shown in the figure. It can be seen that the impulse grounding resistance of the grounding system without the pile foundation external coating device is 12Ω under the impulse current impact, while the impulse grounding resistance of the grounding system with the pile foundation external coating device is a lower 9Ω under the impulse current impact. Therefore, the pile foundation external coating device can reduce the grounding resistance of the grounding system and improve the current conduction performance of the grounding system.

[0106] Furthermore, for the grounding system wrapped with the pile foundation external application device ( Figure 2 ), it can be further determined whether the impulse grounding resistance is greater than a preset resistance threshold. If so, the component parameters of the grounding system can be adjusted with the reduction of the impulse grounding resistance as the optimization goal.

[0107] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0108] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referenced to each other.

[0109] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one 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 present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pile foundation external application device, characterized in that: The pile foundation external coating device is cylindrical and comprises a base layer, a transition layer and an outer coating layer; The outer covering layer wraps the transition layer, and the transition layer wraps the base layer; The resistance of the transition layer satisfies the following formula: in, is the resistance of the transition layer, is the radial coordinate variable, is the inner radius of the transition layer, is the outer radius of the transition layer, is an exponentially decaying distribution function that transitions from the resistivity of the substrate layer to the resistivity of the outer coating layer.

2. The pile foundation external application device according to claim 1, characterized in that: The base layer comprises a high silicon chromium iron alloy; The high-silicon ferrochromium alloy has a silicon content of 3 wt%-4 wt%, a chromium content of 12 wt%-13 wt%, and a carbon content of 2 wt%-3 wt%.

3. The grounding material according to claim 1, characterized in that The transition layer is a gradient ferroferric oxide semiconductor layer, and the gradient ferroferric oxide semiconductor layer comprises an outer layer and an inner layer; The resistivity distribution from the inner layer to the outer layer is from 10 -2 Ω•cm to 10 2 Continuous distribution of Ω•cm.

4. The pile foundation external application device according to claim 3, characterized in that: The inner layer is composed of pure ferrosoferric oxide, and the outer layer is composed of ferrous metaaluminate.

5. The pile foundation external application device according to claim 4, characterized in that: The saturation magnetization of the inner layer is greater than 80emu / g, and the Curie temperature of the inner layer is greater than 580°C.

6. The pile foundation external application device according to claim 3, characterized in that: The outer coating layer includes a graphene film, the thickness of the graphene film is 2nm-5nm, and the in-plane conductivity of the graphene film is greater than 10 7 S / m.

7. The pile foundation external application device according to claim 3, characterized in that: A nickel-copper composite layer is deposited on the surface of the gradient ferroferric oxide semiconductor layer, so that when the copper in the nickel-copper composite layer diffuses to the ferroferric oxide grain boundary to reduce the diffusion activation energy, the nickel in the nickel-copper composite layer and the graphene form nickel carbide for improving the bonding strength between the transition layer and the outer coating.

8. The pile foundation external application device according to claim 6, characterized in that: The outer coating layer further includes a buffer layer, and the buffer layer is used to reduce the interface defect density between the transition layer and the outer coating layer.

9. A ground pile foundation, characterized in that: The grounding pile foundation is externally coated with the pile foundation external coating device according to claim 1, and the pile foundation external coating device is externally coated on the grounding pile foundation in a spirally wound manner.

10. A grounding system, characterized in that: comprising a connecting wire and a plurality of ground piles as claimed in claim 9, wherein the ground piles comprise lead wires; Each of the grounding piles forms a cage structure, and the connecting wire connects the lead-out wires of each of the grounding columns according to the cage structure.

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