Resistance reduction method for improving current diffusion efficiency of grounding body by additionally arranging grounding cloth

Abstract

The invention discloses a resistance reduction method for improving the current diffusion efficiency of a grounding body by additionally arranging grounding cloth. The method comprises the following steps: identifying a current injection point on the grounding body; planning a laying area of the grounding cloth by taking the current injection point as a reference; grounding cloth is selected, and the optimal vertical distance between the grounding cloth and the grounding body is calculated according to the thickness of the grounding cloth; digging a ground groove in a planned laying area, laying grounding cloth at the bottom of the ground groove, and erecting a grounding body according to the calculated optimal vertical distance; according to the method, the resistance reduction effect can be improved, and the grounding cloth and the grounding body can be in the optimal current diffusion state.

Description

Technical Field

[0001] This invention belongs to the field of power system grounding technology, and relates to a resistance reduction method that improves the current dissipation efficiency of the grounding body by adding grounding cloth. Background Technology

[0002] Grounding resistance, as one of the core parameters for measuring the safe and stable operation of a power system, directly affects the safety and reliability of electrical equipment when struck by lightning or experiencing a fault. Ensuring that the grounding resistance is within a reasonable range is a crucial prerequisite for preventing electrical accidents, ensuring personnel safety, and maintaining the normal operation of equipment in power system grounding design. Traditional metal grounding electrodes, such as galvanized steel and copper, have dominated for a long time, meeting the grounding requirements of power systems to a certain extent due to their excellent conductivity. However, with the continuous development of the power industry and increasingly stringent performance requirements for grounding systems, the limitations of traditional metal grounding electrodes have gradually become apparent.

[0003] The emergence of high-performance grounding electrodes (such as graphite) has brought about a new revolution in the field of grounding. Graphite, as a material with unique properties, possesses many characteristics superior to traditional metals. Firstly, its corrosion resistance is exceptional. In the complex chemical environment of soil, traditional metal grounding electrodes are easily corroded by various chemicals, leading to oxidation, rust, and increased resistance, even breakage, severely impacting the performance and lifespan of the grounding system. In contrast, graphite grounding electrodes can resist the erosion of acids, alkalis, salts, and other corrosive substances in the soil, maintaining stable physical and chemical properties over a long period, significantly extending the lifespan of the grounding electrode and reducing the risk of grounding faults caused by electrode damage.

[0004] Secondly, graphite grounding electrodes possess excellent flexibility. In the actual construction of grounding projects, grounding electrodes often need to be bent and laid according to different terrain and soil conditions. Traditional metal grounding electrodes, due to their hardness, are prone to cracking or even breaking during bending, causing significant inconvenience to construction and increasing construction costs and time. Graphite grounding electrodes, on the other hand, are flexible and can easily adapt to various complex construction environments, facilitating installation and laying by construction personnel, thus improving construction efficiency and quality.

[0005] However, despite the numerous advantages of high-performance graphite grounding electrodes, they still face some challenges in practical applications. Particularly in environments with high soil resistivity or complex soil structures, the limited current-dissipating area of ​​a single grounding electrode becomes a key factor restricting its performance. Soil resistivity is an important indicator of soil conductivity; the higher the soil resistivity, the worse the soil's conductivity, and the greater the resistance encountered by current propagation through the soil. In such cases, a single grounding electrode struggles to effectively distribute the current into the surrounding soil, causing most of the current to concentrate on the surface of the grounding electrode.

[0006] Meanwhile, the current dissipation process of a single grounding electrode is also significantly affected by the "end effect" and the "shielding effect." The "end effect" refers to the phenomenon where, when current is released at the ends of a grounding electrode, the release of current is more concentrated in the end region due to the special geometry and electric field distribution at the ends, while the current release in the middle of the grounding electrode is relatively less. This phenomenon is similar to a pipe open at both ends, where the water flow is more concentrated at the two outlets, while the flow in the middle of the pipe is relatively weaker. The "shielding effect" refers to the mutual influence between adjacent grounding electrodes when multiple grounding electrodes exist simultaneously. This interferes with the current distribution near the surface of the grounding electrode, and some current is "shielded" near the surface of the grounding electrode, unable to effectively diffuse into the surrounding soil. This effect is particularly pronounced in complex soil environments, because complex soils may contain soil layers, rocks, etc., with different conductivity properties. These factors further exacerbate the "shielding effect," causing the current to be released more concentratedly from the ends of the grounding electrode, further weakening the current dissipation capacity in the middle.

[0007] Due to the aforementioned factors, the overall resistance reduction effect of a single grounding electrode in environments with high soil resistivity or complex soil conditions is insufficient to meet stringent engineering requirements. In locations with extremely high requirements for power system safety and stability, such as large substations and nuclear power plants, grounding resistance needs to be controlled within an extremely low range to ensure that current can be quickly conducted to the ground in the event of a fault, preventing damage to electrical equipment and personal injury. In such cases, a single grounding electrode often cannot achieve the required resistance reduction effect, necessitating more effective measures to improve the performance of the grounding system.

[0008] While some existing technologies propose using grounding cloth to increase the current dissipation area, these studies lack a precise and quantitative engineering guidance method. Specifically, existing technologies have the following clear shortcomings: 1) The optimal relative positional relationship between the grounding cloth and the grounding electrode is unclear, and the arrangement is based solely on experience, leading to unstable resistance reduction effects, and sometimes even failure due to improper arrangement exacerbating the shielding effect; 2) The precise control of the vertical spacing between the grounding cloth and the grounding electrode is neglected, making it difficult to ensure that it is in the optimal current dissipation state during on-site construction. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for reducing resistance by adding grounding cloth to improve the current dissipation efficiency of the grounding body. This method can improve the resistance reduction effect and make the grounding cloth and the grounding body in the optimal current dissipation state.

[0010] To achieve the above objectives, this invention discloses a method for reducing resistance by adding grounding cloth to improve the current dissipation efficiency of the grounding electrode, comprising: Identify the current injection point on the grounding electrode; Based on the current injection point, plan the laying area of ​​the grounding cloth; Select a grounding cloth and calculate the optimal vertical distance between the grounding cloth and the grounding body based on the thickness of the grounding cloth; Excavate trenches in the planned laying area, lay the grounding cloth at the bottom of the trenches, and then install grounding electrodes according to the calculated optimal vertical distance. Connect the grounding electrode to the grounding wiring.

[0011] Furthermore, the current injection points include the connection point between the main lead wire and the horizontal grounding grid, as well as the key connection points between different horizontal grounding rays.

[0012] Furthermore, the planning area for laying the grounding cloth should meet the following requirements: ,in, X The horizontal distance between the geometric center of the grounding cloth and the target current injection point. R optimal The optimal layout radius is determined by this.

[0013] Furthermore, the optimal vertical spacing between the grounding cloth and the grounding electrode ,in, T Indicates the thickness of the grounding cloth; k This represents the interval coefficient.

[0014] Furthermore, k The optimal value range is 1.0-1.8.

[0015] Furthermore, based on the calculated optimal vertical distance, an insulating positioning device is used to erect the grounding electrode above the grounding cloth.

[0016] Furthermore, the grounding electrode is placed in the slot or support point of the insulating positioning component.

[0017] Furthermore, conductive clamps are used to electrically connect the grounding cloth to the grounding body.

[0018] Furthermore, the conductive clamps are made of copper alloy or stainless steel.

[0019] Furthermore, this also includes backfilling and compacting the grounding trench.

[0020] The present invention has the following beneficial effects: The resistance reduction method described in this invention, which improves the current dissipation efficiency of the grounding body by adding grounding cloth, involves planning the laying area of ​​the grounding cloth based on the current injection point, selecting the grounding cloth, calculating the optimal vertical distance between the grounding cloth and the grounding body based on the thickness of the grounding cloth, maximizing the current dissipation efficiency based on the laying area and the optimal vertical distance, effectively increasing the effective current dissipation area of ​​the grounding system, and providing an efficient, stable and reliable resistance reduction solution for power system grounding engineering. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram showing the relative positions and spacing of the grounding cloth and the grounding body. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0027] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0028] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0030] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0031] The resistance reduction method of the present invention, which improves the current dissipation efficiency of the grounding body by adding grounding cloth, includes the following steps: 1) Determine the reference point: Identify one or more current injection points on the grounding electrode; The location of the most concentrated current inflow in the grounding system is the primary factor determining the effectiveness of the grounding layout. Grounding electrodes exhibit an "end effect," meaning current tends to flow out from the ends of the grounding electrode (usually the current injection point). Therefore, deploying an increased current-dissipating area (grounding cloth) in the area with the highest current density can most effectively reduce grounding resistance.

[0032] Review the design drawings of the power grounding system to determine the main discharge paths for lightning current or fault current. For transmission line towers, there are typically 1-4 down conductors. Then, identify the injection points. On the horizontal grounding grid (or rays), the current injection point is defined as the physical connection point between the down conductor and the horizontal grounding electrode. Then, clearly mark all possible current injection points on the grounding design drawings. These current injection points typically include: the connection point between the main down conductor and the horizontal grounding grid; critical connection points between different horizontal grounding rays; and locations where lightning current is most likely to surge.

[0033] 2) Planning and layout area: Based on the current injection point, plan the area for laying the grounding cloth; Ensure that the grounding wire is deployed in the "hot spot" area where the current dissipation efficiency is highest to overcome the "end effect" of the grounding electrode.

[0034] For each current injection point that needs to be strengthened, an optimal arrangement radius is set with that point as the center. R optimal The geometric center of the grounding cloth should fall within this circular area.

[0035] Let the horizontal distance between the center of the grounding cloth and the target current injection point be... X To achieve the best results, the following must be met: ,in, X This is the horizontal distance between the geometric center of the grounding wire and the target current injection point, expressed in meters (m). In actual construction, this distance... X It should be as small as possible; ideally, the center of the grounding cloth should coincide with the injection point. R optimal The optimal placement radius was determined based on extensive simulation and experimental data, and its value is 0.1 meters (10 centimeters). This range ensures that the grounding cloth is placed in the "hot spot" area with the highest current dissipation efficiency.

[0036] When multiple injection points are close together and their optimal placement areas overlap, a larger grounding cloth can be placed in the overlapping area, or a separate grounding cloth can be used for each injection point. During construction, a measuring tape should be used to measure and position the grounding cloth to ensure the horizontal distance between the center of the grounding cloth and the marked current injection point. X No more than 0.1 meters.

[0037] 3) Calculate the optimal spacing: based on the thickness of the selected grounding cloth. T Calculate the optimal vertical spacing between it and the grounding electrode. D ; Distance between grounding cloth and grounding electrode D There exists an optimal range. If the distance is too small, the electric field shielding effect between the two is too strong, and the current will still preferentially be released from the grounding electrode surface, limiting the effect of the grounding cloth. If the distance is too large, the conduction path impedance between the grounding cloth and the grounding electrode increases, making it difficult for the current to effectively transition to the grounding cloth, thus weakening its auxiliary current dissipation effect. The goal is to find the optimal vertical distance that balances the "shielding effect" and the "conduction impedance," allowing the current to transition from the grounding electrode to the grounding cloth most effectively.

[0038] Measure or obtain the thickness of the grounding cloth to be used according to product specifications. T The unit is meters (m). For example, the thickness of common grounding cloth... T = 0.005 m (5 mm). Calculate the optimal vertical spacing using the following formula. D : ,in, D The vertical distance between the lower surface of the grounding electrode and the upper surface of the grounding cloth is measured in meters (m). T Indicates the thickness of the grounding cloth; k This represents the interval coefficient, which is a dimensionless constant with an optimal value range of 1.0-1.8.

[0039] coefficient k The selection principle is as follows: When the requirement for drag reduction effect is extremely high, and the soil conditions are good and not prone to collapse, the lower limit of the range can be selected (e.g., k = 1.0), to obtain the strongest coupling; when considering ease of construction, the possibility of slight sinking of the positioning component due to long-term soil pressure, or construction in uneven soil, it is recommended to select the upper-middle value of the interval (e.g., k =1.5), to reserve a safety margin and ensure long-term effectiveness; when k When the value exceeds this range, the drag reduction effect decreases significantly.

[0040] 4) Laying and fixing: The usable height is D The insulating positioning component places the grounding electrode above the grounding cloth; To accurately realize the spatial relationships determined in steps 2) and 3) at the construction site, the following operations are performed: 41) Excavation of trenches: Excavate grounding trenches according to the design drawings. The bottom of the trenches should be as flat as possible.

[0041] 42) Laying grounding cloth: Lay the grounding cloth flat at the bottom of the trench.

[0042] 43) Placement of positioning components: Place the pre-customized or selected insulating positioning components (such as "H"-shaped or "U"-shaped engineering plastic brackets) evenly on the grounding cloth at intervals of 0.5-1.0 meters. The height of the positioning components must be strictly equal to the value calculated in step 3). D value.

[0043] 44) Install the grounding electrode: Place the grounding electrode in the slot or support point of the insulating positioning component.

[0044] 45) Precise Positioning: Fine-tune the relative horizontal position of the grounding electrode and the grounding cloth to ensure that the requirements of step 2) are met, i.e., the center of the grounding cloth is within 0.1 meters of the current injection point. At this time, the insulating positioning components simultaneously ensure vertical spacing. D And the horizontal position is fixed.

[0045] 5) Electrical connection: Use conductive clamps to reliably connect the grounding cloth to the grounding electrode; Establish a low-impedance electrical path to ensure that current can be smoothly conducted from the grounding electrode to the grounding cloth.

[0046] Select conductive clamps resistant to soil corrosion; the material can be copper alloy or stainless steel. The conductive clamps should have sufficient mechanical pressure and conductive area. The connection point should be located in the overlapping area of ​​the grounding electrode and the grounding cloth, and as close as possible to the current injection point determined in step 1). Use bolts or other fasteners to tighten the clamps, ensuring tight contact between the grounding cloth and the grounding electrode surface. It is recommended to use at least two clamps on each grounding cloth to ensure reliable connection. After connection, the DC resistance at the connection point can be measured with a multimeter; it should be less than 10 milliohms.

[0047] 6) Backfilling: Backfill and compact the grounding trench; Restore the soil environment and ensure good contact between the grounding device and the surrounding soil to facilitate current dissipation.

[0048] First, backfill with fine soil (sieved soil, free of stones or construction waste), covering the grounding cloth and grounding electrode to a thickness of approximately 20-30 cm. This layer of fine soil is then manually compacted with moderate force to avoid over-compacting and damaging the insulation positioning components or grounding materials. Continue backfilling with the original soil to ground level, followed by final compaction. After backfilling is complete, use a grounding resistance tester (such as a clamp-on grounding resistance meter or a three-electrode tester) to measure the power frequency grounding resistance and compare the results with the data before the modification to verify the resistance reduction effect of this invention.

[0049] This invention has the following characteristics: Significantly improved resistance reduction effect: This invention maximizes the auxiliary current dissipation effect by forcibly configuring the grounding cloth in the area with the highest current density and controlling the optimal interval. The maximum resistance reduction rate can reach 37.8% under power frequency and up to 32% under impact.

[0050] Design and Construction Standardization: This invention provides precise quantitative criteria for "location" and "interval", eliminating blind design and arbitrary construction, and ensuring the consistency of project results.

[0051] High cost-effectiveness: This invention achieves a leap in performance simply by optimizing the configuration of low-cost grounding cloth and simple positioning components, avoiding expensive and complex grounding grid modifications.

[0052] Good long-term stability: The materials used in this invention are corrosion resistant and have stable mechanical connections, ensuring the long-term effectiveness of the drag reduction effect.

[0053] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0054] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0055] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for reducing resistance by adding grounding cloth to improve the current dissipation efficiency of the grounding electrode, characterized in that, include: Identify the current injection point on the grounding electrode; Based on the current injection point, plan the laying area of ​​the grounding cloth; Select a grounding cloth and calculate the optimal vertical distance between the grounding cloth and the grounding body based on the thickness of the grounding cloth; Excavate trenches in the planned laying area, lay the grounding cloth at the bottom of the trenches, and then install grounding electrodes according to the calculated optimal vertical distance. Connect the grounding electrode to the grounding wiring.

2. The resistance reduction method according to claim 1, which improves the current dissipation efficiency of the grounding electrode by adding grounding cloth, is characterized in that, The current injection points include the connection points between the main lead wire and the horizontal grounding grid, as well as the key connection points between different horizontal grounding rays.

3. The resistance reduction method according to claim 1, which improves the current dissipation efficiency of the grounding electrode by adding grounding cloth, is characterized in that... The planned area for laying grounding cloth should meet the following requirements: ,in, X The horizontal distance between the geometric center of the grounding cloth and the target current injection point. R optimal The optimal layout radius is determined by this.

4. The resistance reduction method according to claim 1, which improves the current dissipation efficiency of the grounding electrode by adding grounding cloth, is characterized in that, Optimal vertical spacing between grounding cloth and grounding electrode ,in, T Indicates the thickness of the grounding cloth; k This represents the interval coefficient.

5. The resistance reduction method according to claim 4, which improves the current dissipation efficiency of the grounding electrode by adding grounding cloth, is characterized in that... k The optimal value range is 1.0-1.

8.

6. The resistance reduction method according to claim 1, which improves the current dissipation efficiency of the grounding electrode by adding grounding cloth, is characterized in that, Based on the calculated optimal vertical distance, the grounding electrode is erected above the grounding cloth using an insulating positioning device.

7. The resistance reduction method according to claim 6, which improves the current dissipation efficiency of the grounding electrode by adding grounding cloth, is characterized in that, The grounding electrode is placed in the slot or support point of the insulating positioning component.

8. The resistance reduction method according to claim 1, which improves the current dissipation efficiency of the grounding electrode by adding grounding cloth, is characterized in that, Use conductive clamps to electrically connect the grounding cloth to the grounding electrode.

9. The resistance reduction method according to claim 1, which improves the current dissipation efficiency of the grounding electrode by adding grounding cloth, is characterized in that, The conductive clamp is made of copper alloy or stainless steel.

10. The resistance reduction method according to claim 1, which improves the current dissipation efficiency of the grounding electrode by adding grounding cloth, is characterized in that, Also includes: Backfill and compact the grounding trench.

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