A lightning protection and grounding design method and system for soil-covered vertical oil tanks

Abstract

The present invention relates to the technical field of lightning protection and grounding for petroleum storage tanks, and specifically to a lightning protection and grounding design method and system for earth-covered vertical oil tanks. By comprehensively considering the environmental equipment factors of the tank area, simulating the actual engineering scene, preliminarily determining the layout form and size of the lightning protection and grounding facilities based on the grounding resistance calculation formula, and then further designing and adjusting the layout plan in combination with the simulation software, the optimal layout plan that meets the lightning protection and grounding requirements of the earth-covered vertical oil tank is obtained; by burying a ring conductor with an outer contour that matches the tank body in the earth layer and cooperating with a lightning protection grid to form a reliable lightning protection, the structure is compact, and material costs are saved; by connecting the lightning protection system of the top earth layer, the grounding system inside the tank room, the grounding system in the underground pipe trench between the oil tanks, and the tank area grounding system, the entire tank area is completely protected by lightning protection and grounding, saving the land acquisition area of ​​the project, and convenient maintenance, safe and reliable.

Description

Technical Field

[0001] The invention relates to the technical field of lightning protection and grounding of petroleum storage tanks, and in particular to a lightning protection and grounding design method and system for a soil-covered vertical oil tank. Background Art

[0002] Since earth-covered oil tanks can reduce the evaporation loss of stored oil, delay the deterioration of oil products, and have a certain air concealment effect and safety protection capabilities, more and more reserve oil depots have begun to adopt earth-covered oil tanks. However, accidents of oil tank explosions and fires caused by lightning occur from time to time, causing serious losses to oil depots. Therefore, lightning protection and grounding of earth-covered oil tanks are an important task to ensure the safe operation of oil tanks.

[0003] Most common metal oil tanks for ground storage can be directly used as lightning protection objects because the thickness of the tank top plate reaches 6mm, without the need to consider setting up separate lightning protection facilities. Only the grounding system of the oil tank needs to be considered. However, vertical metal oil tanks placed in reinforced concrete tank rooms cannot use their tank top plates as lightning protection objects. Therefore, it is necessary to comprehensively consider the lightning protection and grounding of the oil tank area according to the project requirements, especially how to set up the lightning protection system is particularly important.

[0004] There is little research on the lightning protection and grounding system of earth-covered vertical oil tanks in the existing technology. There are also inconsistent practices at home and abroad. In addition, the factors considered in the design and implementation are not comprehensive enough, making it difficult to meet the actual engineering safety needs. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a lightning protection and grounding design method for an earth-covered vertical oil tank, which can comprehensively consider the tank area environment, equipment, and material factors, so that the designed lightning protection and grounding system meets the actual engineering safety requirements. At the same time, a lightning protection and grounding system for an earth-covered vertical oil tank is provided, which can meet the lightning protection and grounding requirements of the earth-covered vertical oil tank, and has a compact structure, and is safe and reliable.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a lightning protection and grounding design method for a soil-covered vertical oil tank, comprising the following steps:

[0007] S1, collect and organize the structural parameters and material electrical parameters of the earth-covered vertical oil tank project;

[0008] S2, performing three-dimensional modeling of the earth-covered vertical oil tank according to the engineering structure parameters and material electrical parameters, and importing the three-dimensional model into simulation analysis software;

[0009] S3, based on the actual safety grounding resistance value required by the project and the grounding resistance calculation formula, preliminarily determine the layout and size of the lightning protection and grounding system of the covered vertical oil tank;

[0010] S4, combining the three-dimensional model and the initially determined layout form and size of the lightning protection and grounding system of the earth-covered vertical oil tank, and analyzing the lightning protection effect of the initially determined lightning protection and grounding system through simulation analysis software;

[0011] S5, by adjusting the object positioning and numerical settings of the simulation software, comparing the simulation results, the optimal layout and size of the lightning protection and grounding system are obtained, and the simulation software is used to output the result report required for the project.

[0012] Furthermore, the engineering structural parameters include the size of the oil storage tank, the depth of the tank room, and the size of the tank room shell top structure; the material electrical parameters include the steel plate of the oil storage tank, the steel bars and concrete of the tank room, the selection parameters of the lightning protection and grounding materials, and the soil resistivity parameters of the project site.

[0013] Furthermore, the grounding resistance calculation formula is as follows:

[0014] R n =a1×R e

[0015] Where: R n is the safe grounding resistance value actually required by the project, R e is the theoretical grounding resistance value, and a1 is the actual engineering correction coefficient.

[0016] Furthermore, the theoretical grounding resistance value R e And the calculation formula of the actual engineering correction coefficient a1 is as follows:

[0017]

[0018]

[0019]

[0020] Where: S is the total area of ​​the grounding grid, d is the diameter of the grounding body or the equivalent diameter, h is the buried depth of the grounding body, L0 is the total length of the outer edge of the grounding grid, and L is the total length of the grounding body.

[0021] A lightning protection and grounding system for a soil-covered vertical oil tank is obtained according to the above design method, and includes a lightning protection system for the top soil layer, a grounding system inside the tank room, a grounding system in the underground pipe trench between the oil tanks, and an overall grounding system for the oil tank area;

[0022] The soil layer lightning protection system is arranged in the soil layer at the top of the soil-covered vertical oil tank, and includes a ring conductor 1. The arrangement path of the ring conductor 1 is adapted to the outer contour of the metal tank body 5 below it, and the radius of the ring conductor 1 is larger than the radius of the metal tank body 5. A lightning protection grid 2 is installed in the ring conductor 1;

[0023] The tank chamber internal grounding system is arranged on the tank chamber wall of the earth-covered vertical oil tank, and comprises a horizontal conductor 3, the horizontal conductor 3 is fixedly connected to the metal tank body 5 through a connection point 4, and the metal tank body 5 is electrically connected to the breathing valve 6 and the oil measuring hole 7 arranged on the upper part of the metal tank body 5 through a grounding wire I15;

[0024] The grounding system in the underground trench between the oil tanks is arranged in the underground trench 8 between the vertical oil tanks covered with soil, and a connecting grounding body 9 is arranged in the underground trench 8, and the connecting grounding body 9 is electrically connected to the oil pipe 10, valve 11 and instrument 12 arranged in the underground trench 8 through the grounding wire II 16;

[0025] The overall grounding system of the oil tank area includes a horizontal grounding body 13 and a vertical grounding body 14 connected together, and the number of the horizontal grounding body 13 and the vertical grounding body 14 is calculated according to the requirements of the engineering grounding resistance value;

[0026] The annular conductor 1 is connected to the vertical grounding body 14 via the horizontal grounding body 13 , and the horizontal conductor 3 is connected to the horizontal grounding body 13 via the connecting grounding body 9 .

[0027] Furthermore, the lightning protection grid 2 is a square grid, and the size is not greater than 7m×7m; the buried depth of the annular conductor 1 and the lightning protection grid 2 in the soil layer on the top of the oil tank is 0.3m.

[0028] Furthermore, the horizontal conductor 3 is openly installed along the inner wall of the tank room, and the installation height is 0.5m from the floor of the tank room; there are multiple connection points 4, and the distance between any two connection points 4 along the circumference direction of the metal tank body 5 is not greater than 30m.

[0029] Furthermore, the connection grounding body 9 is openly installed along the inner wall of the underground trench 8, and the installation height is 0.5m from the floor height of the trench.

[0030] Furthermore, the horizontal grounding electrodes 13 are arranged along the outer contour of the oil tank area, and the middle parts of the horizontal grounding electrodes 13 are connected to form a square grid with a size not greater than 40m×40m, and the buried depth of the horizontal grounding electrodes 13 underground in the oil tank area is 0.6m; the vertical grounding electrodes 14 are arranged along the horizontal grounding electrodes 13, and the spacing between adjacent vertical grounding electrodes 14 is not less than 5m and not greater than 30m, and the buried depth of the vertical grounding electrodes 14 underground in the oil tank area is 0.6m.

[0031] Furthermore, the materials of the annular conductor 1, the lightning protection grid 2, the horizontal conductor 3, and the contact grounding body 9 are 40mm×4mm hot-dip galvanized flat steel;

[0032] The material of the horizontal grounding body 13 is hot-dip galvanized round steel with a diameter of 16 mm;

[0033] The vertical grounding body 14 is made of hot-dip galvanized angle steel of ∠50mm×50mm×5mm and has a length of 2.5m;

[0034] The grounding conductor I15 and the grounding conductor II16 are made of a material with a cross-sectional area of ​​25 mm 2 Copper core PVC insulated soft wire.

[0035] Compared with the prior art, the present invention has the following main advantages:

[0036] 1. By comprehensively considering the tank area environment, equipment, and material factors, simulating the actual engineering scenario, and preliminarily determining the layout form and size of the lightning protection grounding facilities based on the grounding resistance calculation formula, and then further designing and adjusting the layout of the lightning protection grounding facilities in combination with the simulation software, the optimal layout plan that meets the lightning protection grounding requirements of the covered vertical oil tank can be obtained more efficiently and accurately;

[0037] 2. By burying a ring conductor with an outer contour that matches the tank body in the soil layer on the top of each vertical oil tank, together with a lightning protection grid, the vertical oil tank can obtain sufficient and reliable lightning protection, while ensuring a compact structure and saving material costs;

[0038] 3. By connecting the lightning protection system of the top soil layer, the internal grounding system of the tank room, the grounding system in the underground pipe trench between the oil tanks and the tank area grounding system, a hierarchical and structural grounding network covering the entire tank area is formed, which provides complete lightning protection and grounding for the entire tank area, can save the land acquisition area of ​​the project, and is easy to maintain, safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of a lightning protection and grounding design method for a soil-covered vertical oil tank of the present invention;

[0040] Figure 2 This is a schematic diagram of the top soil cover lightning protection system of the present invention;

[0041] Figure 3 It is a schematic diagram of the internal grounding system of the tank chamber of the present invention;

[0042] Figure 4 This is a schematic diagram of the grounding system in the underground pipe trench connecting the oil tanks of the present invention;

[0043] Figure 5 This is a schematic diagram of the overall grounding system of the oil tank area of ​​the present invention;

[0044] Figure 6 It is a schematic diagram of three-dimensional modeling of the simulation software of the present invention;

[0045] Figure 7 It is a schematic diagram of inputting parameters of the simulation software of the present invention;

[0046] Figure 8 This is a diagram of the ground resistance analysis results output by the simulation software of the present invention.

[0047] In the figure: 1. Ring conductor; 2. Lightning protection grid; 3. Horizontal conductor; 4. Connection point; 5. Metal tank; 6. Breathing valve; 7. Oil measuring hole; 8. Underground trench; 9. Connection grounding electrode; 10. Oil pipeline; 11. Valve; 12. Instrument; 13. Horizontal grounding electrode; 14. Vertical grounding electrode; 15. Grounding wire I; 16. Grounding wire II. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0049] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0050] 1. A lightning protection and grounding design method for vertical oil tanks covered with soil

[0051] like Figure 1 As shown, a lightning protection and grounding design method for earth-covered vertical oil tanks implemented according to the present invention can simulate actual engineering scenarios, preliminarily determine the layout and size of lightning protection and grounding facilities based on the grounding resistance calculation formula, and then further design and adjust the layout of lightning protection and grounding facilities in combination with simulation software to meet the needs of lightning protection for earth-covered vertical oil tanks, achieve actual engineering safety conditions, and reduce engineering risks.

[0052] The specific steps include:

[0053] S1, collect and organize the structural parameters and material electrical parameters of earth-covered vertical oil tank engineering.

[0054] The engineering structural parameters include the size of the oil storage tank, the depth of the tank chamber, and the size of the tank chamber shell top structure;

[0055] The material electrical parameters include the steel plates of the metal oil storage tanks, the steel bars and concrete of the tank chambers, the selection parameters of lightning protection and grounding materials, and the soil resistivity parameters of the project site;

[0056] S2, based on the engineering structural parameters and material electrical parameters of the earth-covered vertical oil tank, three-dimensional modeling of the earth-covered vertical oil tank is performed, and the three-dimensional model is imported into the simulation analysis software (in this example, the HIFREQ and FFTSES modules in the power system grounding analysis software CDEGS).

[0057] S3, based on the actual safety grounding resistance value required by the project (the grounding resistance in this example is not more than 4Ω), and based on the grounding resistance calculation formula, preliminarily determine the layout and size of the lightning protection and grounding system of the covered vertical oil tank;

[0058] The ground resistance calculation formula is as follows:

[0059] R n =a1×R e

[0060] Where: R n is the safe grounding resistance value actually required by the project, R e is the theoretical grounding resistance value, and a1 is the actual engineering correction coefficient.

[0061] The R e The calculation formulas for a1 are as follows:

[0062]

[0063]

[0064]

[0065] Where: S is the total area of ​​the grounding grid, d is the diameter of the grounding body or the equivalent diameter, h is the buried depth of the grounding body, L0 is the total length of the outer edge of the grounding grid, and L is the total length of the grounding body.

[0066] S4, based on the layout and size and shape of the lightning protection and grounding system preliminarily determined, combined with the three-dimensional model of the earth-covered vertical oil tank, the lightning protection and grounding system simulation analysis is performed through the simulation software to maximize the engineering simulation and analyze the lightning protection effect of the preliminarily determined lightning protection and grounding system.

[0067] S5, by adjusting the object positioning and numerical settings of the simulation software, comparing the simulation results, the optimal layout and size shape of the lightning protection and grounding system are obtained, and the simulation software is used to output the result report required for the project to meet the standard specifications for engineering design and engineering acceptance.

[0068] 2. A lightning protection and grounding system for vertical oil tanks covered with soil

[0069] Based on the same inventive concept, the embodiment of the present application also provides a lightning protection and grounding system for an earth-covered vertical oil tank. The lightning protection and grounding design method for an earth-covered vertical oil tank is used, which is suitable for oil tank areas with limited storage areas and high requirements for storage medium safety protection levels, and can meet the lightning protection and grounding requirements of earth-covered vertical oil tanks (the capacity of the earth-covered vertical oil tank in this example is 2000m 3 The dimensions are 19000mm in diameter × 7524mm in height. There are 4 earth-covered vertical oil tanks in the oil tank area).

[0070] Specifically, it includes the top cover lightning protection system, the internal grounding system of the tank room, the grounding system in the underground pipe trench between oil tanks, and the overall grounding system of the oil tank area.

[0071] 1. Top cover layer lightning protection system

[0072] like Figure 2 As shown, a top soil layer lightning protection system is provided in the top soil layer of each vertical oil tank, and the top soil layer lightning protection system includes a ring conductor 1 (specifically, a ring grounding wire) and a lightning protection grid 2 (specifically, a grid-shaped metal conductor).

[0073] The center of the annular conductor 1 corresponds vertically to the center of the earth-covered vertical oil tank below it, and the radius of the annular conductor 1 is larger than the radius of the earth-covered vertical oil tank (specifically, it can be 3m larger than the radius of the earth-covered vertical oil tank).

[0074] A lightning protection grid 2 is installed in the annular conductor 1. The lightning protection grid 2 is a square grid, and the size of the lightning protection grid 2 is not greater than 7m×7m.

[0075] The buried depth of the annular conductor 1 and the lightning protection grid 2 in the soil layer on the top of the oil storage tank is 0.3 m, and the buried depth is independent of the thickness of the soil layer.

[0076] The annular conductor 1 is connected to a horizontal grounding body 13 covering the entire tank area.

[0077] 2. Internal grounding system of tank room

[0078] like Figure 3 As shown, an internal grounding system is provided in the tank chamber of each earth-covered vertical oil tank, and the internal grounding system includes a horizontal conductor 3 (specifically, a ring grounding wire). The horizontal conductor 3 is openly laid along the inner wall of the tank chamber, and the installation height is 0.5m from the floor of the tank chamber.

[0079] At the same time, the horizontal conductor 3 is fixedly connected to the metal tank body 5 through a connection point 4 (specifically, it can be welded). There are multiple connection points 4, and the distance between any two connection points 4 along the circumference direction of the metal tank body 5 is not greater than 30m.

[0080] The metal tank body 5 is electrically connected to the breathing valve 6 and the oil measuring hole 7 arranged on the top of the oil storage tank through the grounding wire I.

[0081] The horizontal conductor 3 is connected to a horizontal grounding body 13 covering the entire tank area through a contact grounding body 9 arranged in an underground pipe trench 8 of the tank room.

[0082] 3. Grounding system in underground trench between oil tanks

[0083] like Figure 4 As shown, a connecting grounding body 9 is arranged in the underground trench 8 between the oil tanks. The connecting grounding body 9 is exposedly laid along the inner wall of the underground trench 8, and the installation height is 0.5m from the floor height of the trench. The connecting grounding body 9 is connected to the horizontal conductor 3 in each tank room.

[0084] At the same time, the contact grounding body 9 is electrically connected to the oil pipe 10, valve 11 and instrument 12 arranged in the underground pipe trench 8 through the grounding wire II.

[0085] The connection grounding body 9 is connected to a horizontal grounding body 13 covering the entire tank area.

[0086] 4. Overall grounding system of oil tank area

[0087] like Figure 5 As shown, horizontal grounding electrodes 13 and vertical grounding electrodes 14 connected together are provided in the entire oil tank area, and the number of the horizontal grounding electrodes 13 and the vertical grounding electrodes 14 is calculated based on the test value of the regional soil resistivity and the requirement of the engineering grounding resistance value (not greater than 4Ω).

[0088] Specifically, the horizontal grounding electrodes 13 are arranged along the outer contour of the oil tank area, and the middle parts of the horizontal grounding electrodes 13 are connected to form a square grid with a size not greater than 40m×40m. The horizontal grounding electrodes 13 are buried at a depth of 0.6m.

[0089] The vertical grounding electrodes 14 are arranged along the horizontal grounding electrodes 13, the interval between adjacent vertical grounding electrodes 14 is not less than 5m and not more than 30m, and the vertical grounding electrodes 14 are buried at a depth of 0.6m.

[0090] At the same time, the horizontal grounding body 13 is connected to the annular conductor 1 of each earth-covered vertical oil tank in the oil tank area and the connecting grounding body 9 arranged in the underground trench 8.

[0091] At this point, the top soil cover lightning protection system in the entire oil tank area, the internal grounding system of the tank room, and the grounding system in the underground trench between oil tanks are connected through the ring conductor 1, the lightning protection grid 2, the horizontal conductor 3, the connection point 4, the metal tank body 5, the connecting grounding body 9, the grounding wire I, the grounding wire II, the horizontal grounding body 13 and the vertical grounding body 14 to form a complete lightning protection and grounding system, and the grounding resistance is not more than 4Ω.

[0092] The annular conductor 1, the lightning protection grid 2, the horizontal conductor 3, and the connecting grounding body 9 can be specifically made of 40×4 (mm) hot-dip galvanized flat steel;

[0093] The horizontal grounding body 13 can be specifically made of hot-dip galvanized round steel with a diameter of 16 mm;

[0094] The grounding wire I and the grounding wire II may specifically have a cross-sectional area of ​​25 mm 2 Copper core PVC insulated flexible wire;

[0095] The vertical grounding body 14 can be specifically a hot-dip galvanized angle steel of ∠50×50×5 (mm) and a length of 2.5m.

[0096] 5. Effect verification

[0097] The lightning protection and grounding system of the above-mentioned earth-covered vertical oil tank is simulated by using simulation analysis software (in this example, the HIFREQ and FFTSES modules in the power system grounding analysis software CDEGS).

[0098] like Figures 6-7 As shown in the figure, according to the engineering structural parameters and material electrical parameters of the earth-covered vertical oil tank, a three-dimensional model of the earth-covered vertical oil tank is built. According to the layout and size shape of the lightning protection and grounding system of the earth-covered vertical oil tank, combined with the three-dimensional model of the earth-covered vertical oil tank, a lightning protection and grounding system simulation analysis is carried out. The analysis results are shown in Figure 8 shown.

[0099] from Figure 8 It can be seen that the overall grounding resistance value (Impedance of Grounding System) of this system is 0.9406224Ω, which meets the lightning protection grounding resistance value requirements of the covered vertical oil tank, and further verifies the rationality of the technical solution, which can be used as a reference for the implementation of actual projects.

[0100] The system was applied in a certain project - oil security facility project. The oil depot project is geographically sensitive and has special properties. There are few standards and specifications to follow, and the safety protection level of the storage medium is required to be high. Under the premise of meeting most standards and specifications, considering that the safety level of this type of project is higher than that of ordinary commercial oil storage depots, and under the premise of meeting the operability of the project, this system is adopted.

[0101] After the system is applied, a complete lightning protection and grounding system can be established, which optimizes the land acquisition area of ​​the project, improves the reliability of the project's safe operation, reduces the safety risks of the project's production and operation, and improves the project's operability and safety benefits.

[0102] In summary, the above-mentioned lightning protection and grounding design method and system for earth-covered vertical oil tanks is adopted. By comprehensively considering the tank area environment, equipment, and material factors, simulating the actual engineering scenario, and preliminarily determining the layout form and size of the lightning protection and grounding facilities based on the grounding resistance calculation formula, and then further designing and adjusting the layout of the lightning protection and grounding facilities in combination with the simulation software, the optimal layout plan that meets the lightning protection and grounding requirements of the earth-covered vertical oil tank can be obtained more efficiently and accurately.

[0103] By burying a ring conductor with an outer contour matching the tank body in the soil layer on the top of each vertical oil tank, together with a lightning protection grid, the vertical oil tank can obtain sufficient and reliable lightning protection, while ensuring a compact structure and saving material costs;

[0104] By connecting the lightning protection system of the top soil layer, the internal grounding system of the tank room, the grounding system in the underground pipe trench between oil tanks and the tank area grounding system, a hierarchical and clearly structured grounding network covering the entire tank area is formed, providing complete lightning protection and grounding for the entire tank area, which can save land acquisition area for the project, and is easy to maintain, safe and reliable.

[0105] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A lightning protection and grounding system for a vertical oil tank covered with soil, which is designed using a lightning protection and grounding design method for a vertical oil tank covered with soil, and is characterized in that: It includes the top soil cover lightning protection system, the tank room internal grounding system, the underground pipe trench grounding system between oil tanks and the overall grounding system of the oil tank area; The soil layer lightning protection system is arranged in the soil layer at the top of the soil-covered vertical oil tank, and comprises a ring conductor (1). The arrangement path of the ring conductor (1) is adapted to the outer contour of the metal tank body (5) below it, and the radius of the ring conductor (1) is greater than the radius of the metal tank body (5). A lightning protection grid (2) is installed in the ring conductor (1); The tank chamber internal grounding system is arranged on the tank chamber inner wall of the earth-covered vertical oil tank, and comprises a horizontal conductor (3). The horizontal conductor (3) is fixedly connected to a metal tank body (5) via a connection point (4). The metal tank body (5) is electrically connected to a breathing valve (6) and an oil measuring hole (7) arranged on the upper part of the metal tank body (5) via a grounding conductor I (15). The grounding system in the underground trench for connecting oil tanks is arranged in the underground trench (8) between each of the earth-covered vertical oil tanks. A connecting grounding body (9) is arranged in the underground trench (8). The connecting grounding body (9) is electrically connected to the oil pipe (10), valve (11) and instrument (12) arranged in the underground trench (8) through a grounding conductor II (16); The oil tank area integral grounding system comprises a horizontal grounding body (13) and a vertical grounding body (14) connected together, and the number of the horizontal grounding body (13) and the vertical grounding body (14) is calculated according to the requirements of the engineering grounding resistance value; The annular conductor (1) is connected to a vertical grounding body (14) via a horizontal grounding body (13), and the horizontal conductor (3) is connected to a horizontal grounding body (13) via a connecting grounding body (9); The design method comprises the following steps: S1, collect and organize the structural parameters and material electrical parameters of the earth-covered vertical oil tank project; S2, performing three-dimensional modeling of the earth-covered vertical oil tank according to the engineering structure parameters and material electrical parameters, and importing the three-dimensional model into simulation analysis software; S3, based on the actual safety grounding resistance value required by the project and the grounding resistance calculation formula, preliminarily determine the layout and size of the lightning protection and grounding system of the covered vertical oil tank; S4, combining the three-dimensional model and the initially determined layout form and size of the lightning protection and grounding system of the earth-covered vertical oil tank, and analyzing the lightning protection effect of the initially determined lightning protection and grounding system through simulation analysis software; S5, by adjusting the object positioning and value setting of the simulation software, comparing the simulation results, obtaining the optimal layout and size of the lightning protection and grounding system, and using the simulation software to output the result report required for the project; The engineering structural parameters include the size of the oil storage tank, the depth of the tank room, and the size of the tank room shell top structure; the material electrical parameters include the steel plate of the oil storage tank, the steel bars and concrete of the tank room, the selection parameters of the lightning protection and grounding materials, and the soil resistivity parameters of the project site; The grounding resistance calculation formula is as follows: R n =a1×R e Where: R n is the safe grounding resistance value actually required by the project, R e is the theoretical grounding resistance value, a1 is the actual engineering correction coefficient; The theoretical grounding resistance value R e And the calculation formula of the actual engineering correction coefficient a1 is as follows: Where: S is the total area of ​​the grounding grid, d is the diameter of the grounding body or the equivalent diameter, h is the buried depth of the grounding body, L0 is the total length of the outer edge of the grounding grid, and L is the total length of the grounding body.

2. The lightning protection and grounding system for a vertical oil tank covered with earth according to claim 1 is characterized in that: The lightning protection grid (2) is a square grid with a size not greater than 7m×7m; the buried depth of the annular conductor (1) and the lightning protection grid (2) in the soil layer on the top of the oil tank is 0.3m.

3. The lightning protection and grounding system for a vertical oil tank covered with earth according to claim 1 is characterized in that: The horizontal conductor (3) is openly installed along the inner wall of the tank chamber, and the installation height is 0.5m from the floor of the tank chamber; there are multiple connection points (4), and the distance between any two connection points (4) along the circumference direction of the metal tank body (5) is not greater than 30m.

4. The lightning protection and grounding system for a vertical oil tank covered with earth according to claim 1 is characterized in that: The connection grounding body (9) is openly installed along the inner wall of the underground pipe trench (8), and the installation height is 0.5m from the floor height in the pipe trench.

5. The lightning protection and grounding system for a vertical oil tank covered with earth according to claim 1 is characterized in that: The horizontal grounding electrodes (13) are arranged along the outer contour of the oil tank area, and the middle parts of the horizontal grounding electrodes (13) are connected to form a square grid with a size not greater than 40m×40m, and the buried depth of the horizontal grounding electrodes (13) underground in the oil tank area is 0.6m; the vertical grounding electrodes (14) are arranged along the horizontal grounding electrodes (13), and the spacing between adjacent vertical grounding electrodes (14) is not less than 5m and not greater than 30m, and the buried depth of the vertical grounding electrodes (14) underground in the oil tank area is 0.6m.

6. The lightning protection and grounding system for a vertical oil tank covered with earth according to claim 1 is characterized in that: The materials of the annular conductor (1), the lightning protection grid (2), the horizontal conductor (3) and the connecting grounding body (9) are 40 mm×4 mm hot-dip galvanized flat steel; The material of the horizontal grounding body (13) is hot-dip galvanized round steel with a diameter of 16 mm; The vertical grounding body (14) is made of hot-dip galvanized angle steel of ∠50mm×50mm×5mm and has a length of 2.5m; The grounding conductor I (15) and the grounding conductor II (16) are made of a material having a cross-sectional area of ​​25 mm 2 Copper core PVC insulated soft wire.

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