Design method of oil tank grounding system considering seasonal environmental factor

Abstract

The present application relates to the technical field of oil tank grounding, in particular to a kind of oil tank grounding system design method considering seasonal environmental factor influence.Through comprehensively considering the grounding system of oil tank and environmental seasonal factor, simulating engineering actual scene, the voltage requirement of grounding system is initially determined based on contact voltage and step voltage calculation formula, then the important performance parameters of grounding grid under the influence of various seasonal factors are comprehensively analyzed by combining simulation software, the design of oil tank grounding system is optimized and adjusted, which conforms to engineering practice;The present application can also be applicable to permafrost regions such as high cold and high altitude, and summarizes an efficient and reliable design method for oil tank grounding system in special seasons and special geological conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil tank grounding, in particular to a design method of oil tank grounding system considering seasonal environmental factor influence. BACKGROUND

[0002] The safe storage of oil products in large oil depots is one of the main factors affecting China's national economy and social stability, and how to ensure the safe and stable operation of oil tank facilities plays a very important role in large oil and gas projects. The grounding system is recognized as one of the four facilities for safe operation of oil tanks. How to efficiently avoid short circuit, fire and other accidents in large oil depots affected by the environment has been one of the important problems in the field of petroleum industry.

[0003] Because the accident of oil depot (oil tank) facilities has a large hazard range, it is generally located in areas with very sparse population, and the soil environment is greatly affected by seasonal climate. China is in a monsoon climate area, and the four seasons change very obviously, which puts higher requirements on the design of oil depot grounding system.

[0004] Rainy season and winter are the two seasons with the most obvious changes in soil. The high precipitation in the rainy season and the large area of frozen soil formed in the northern and high-altitude areas in winter will cause great changes in soil resistivity. The oil tank grounding system designed by the conventional standard may not meet the engineering design standard in special seasons, and the intrinsic safety of the project cannot be realized.

[0005] The existing technology has less analysis and research on the influence of seasonal factors on the safety performance of oil depot grounding system. In areas with large seasonal climate changes, the safety performance of the oil tank grounding system designed by the traditional method is difficult to guarantee, and the safety requirements of the actual project cannot be met. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a design method of oil tank grounding system considering seasonal environmental factor influence, which can comprehensively consider the influence of weather and environmental factors of oil tank grounding system, so that the designed oil tank grounding system is more safe and reliable, and meets the use requirements in the case of large seasonal climate changes.

[0007] To solve the above technical problems, the technical scheme adopted by the present application is:

[0008] A design method of oil tank grounding system considering seasonal environmental factor influence, specifically comprising the following steps:

[0009] S1, collecting and arranging the engineering structure parameters and material electrical parameters of the oil tank grounding system and the soil environmental parameters of the oil tank site;

[0010] S2, according to the engineering structure parameters and material electrical parameters, a three-dimensional model of the oil tank grounding system is established, and the model is simulated and analyzed by using a grounding analysis software;

[0011] S3, based on the contact voltage and step voltage calculation formula, the required safety grounding voltage value of the oil tank grounding system is determined;

[0012] S4, based on the grounding analysis software, the influence of different seasonal environmental factors on the contact voltage and step voltage of the oil tank grounding system is simulated by changing the soil environmental parameters;

[0013] S5, the oil tank grounding system is improved, and the simulation results of each improvement scheme are compared, and the improvement scheme with the highest safety grounding voltage value is obtained as the optimal scheme, and the simulation software output result report is used;

[0014] S6, according to the result report, the design of the oil tank grounding system is carried out.

[0015] Further, in step S1, the engineering structure parameters include the size of the oil tank, the height 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 tank, the steel and concrete of the tank room, and the resistance parameters of the grounding material; the soil environmental parameters include the soil resistivity parameters of the place where the oil tank is located and the seasonal environmental parameters.

[0016] Further, in step S2, the oil tank grounding system includes a horizontal grounding body 1 and a vertical grounding body 2; the horizontal grounding body 1 constitutes a 100m*100m uniform grounding net with a grid spacing of 10m and a buried depth of 0.6m; the number and length parameters of the vertical grounding body 2 are adjustable.

[0017] Further, in step S3, the calculation formula of the contact voltage E touch50 and the step voltage E step50 is as follows:

[0018]

[0019]

[0020]

[0021] In the formula, ρ s is the resistivity of the upper soil, ρ is the resistivity of the lower soil, unit is Ω·m; h s is the thickness of the upper soil, unit is m; t is the fault current duration, unit is s; C s is the surface attenuation coefficient.

[0022] Further, in step S3, the safety voltage value takes the minimum value of the contact voltage and the step voltage.

[0023] Further, in step S4, the different seasonal environmental factors specifically include sunny environmental, rainy environmental and winter environmental.

[0024] The sunny environmental adopts the uniform soil environment of 200Ω·m to simulate the influence on the oil tank grounding system.

[0025] The rainy environmental adopts the double-layer soil environment to simulate the influence on the oil tank grounding system, and the lower layer soil resistivity is not changed, the upper layer soil resistivity is taken in the range of 20-200Ω·m, and the thickness is taken in the range of 0-1.6m to simulate different rainfall in the rainy season.

[0026] The winter environmental adopts the double-layer soil environment to simulate the influence on the oil tank grounding system, and the lower layer soil resistivity is not changed, the upper layer soil resistivity is taken in the range of 200-8000Ω·m, and the thickness is taken in the range of 0-1.6m to simulate the frozen soil environment in different periods of winter.

[0027] Further, in step S5, the improvement scheme includes adding granite material on the ground surface of the oil tank area and changing the number and length of the vertical grounding bodies.

[0028] Further, in step S6, the result report includes the length and number of the vertical grounding bodies corresponding to the optimal scheme.

[0029] Further, the horizontal grounding body 1 material is hot-dip galvanized round steel with a diameter of 16mm, and the vertical grounding body 2 material is hot-dip galvanized angle steel with ∠50mm*50mm*5mm.

[0030] Compared with the prior art, the present application has the following main advantages:

[0031] 1. By comprehensively considering the grounding system of the oil tank and the environmental seasonal factors, simulating the actual engineering scene, preliminarily determining the voltage requirement of the grounding system based on the contact voltage and the step voltage calculation formula, then comprehensively analyzing the important performance parameters of the grounding net under the influence of various seasonal factors, optimizing and adjusting the design of the oil tank grounding system, which conforms to the engineering practice.

[0032] 2. According to the influence principle of the seasonal factors on the grounding system, the double-layer soil structure with variable upper layer soil thickness and resistivity is adopted to simulate various typical seasonal conditions, and the change rules of the grounding resistance, the contact voltage and the step voltage are analyzed and summarized, which more truly and comprehensively reflects the influence of the seasonal factors on the oil tank grounding system.

[0033] 3、The application can also be applied to permafrost regions such as high-cold and high-altitude regions, and is suitable for grounding systems of oil tank regions under special seasons and special geological conditions. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A flow chart of the oil tank grounding system design method considering the influence of seasonal environmental factors according to the application;

[0035] Figure 2 A three-dimensional modeling schematic diagram of the simulation software according to the application;

[0036] Figure 3 A trend chart of the parameter change influence of the oil tank grounding grid in the rainy season;

[0037] Figure 4 A trend chart of the parameter change influence of the oil tank grounding grid in the winter frozen soil;

[0038] Figure 5 A parameter input schematic diagram of the simulation software according to the application;

[0039] Figure 6 A grounding resistance analysis result chart output by the simulation software according to the application.

[0040] In the figure: 1, horizontal grounding body; 2, vertical grounding body. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the application clearer and more apparent, the application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application and do not limit the application. In addition, the technical features involved in each embodiment of the application described below can be combined with each other as long as they do not conflict with each other.

[0042] It should be pointed out that according to the needs of implementation, each step / component described in the present application can be split into more steps / components, or two or more steps / components or part of the operations of the steps / components can be combined into a new step / component to achieve the purpose of the application.

[0043] One, a design method of an oil tank grounding system considering the influence of seasonal environmental factors

[0044] As shown in Figure 1 The design method of an oil tank grounding system considering the influence of seasonal environmental factors according to the application can simulate the actual engineering scene, preliminarily determine the required safety grounding voltage of the oil tank grounding system based on the step voltage and contact voltage calculation formula, and then further design and improve the arrangement of the oil tank grounding grid in combination with the simulation software to achieve the actual engineering safety condition and reduce the engineering risk.

[0045] Specifically comprising the following steps:

[0046] S1, collecting and arranging engineering structure parameters and material electrical parameters of the oil tank grounding system and soil environment parameters of the oil tank site.

[0047] The engineering structure parameters include the size of the oil storage tank, the height of the tank chamber, and the size of the tank chamber shell top structure; the material electrical parameters include the resistance selection parameters of the steel plate of the oil storage tank, the steel reinforcement and concrete of the tank chamber, and the grounding material; and the soil environment parameters include the soil resistivity parameters and seasonal environmental parameters of the oil tank site.

[0048] S2, according to the engineering structure parameters and material electrical parameters, performing three-dimensional modeling on the oil tank grounding system (such as Figure 2 The oil tank grounding system includes a horizontal grounding body 1 and a vertical grounding body 2), and using grounding analysis software to perform simulation analysis on the model (in this example, the SESCAD module in the grounding analysis software CDEGS is used for modeling, and the MALZ module is used for simulation analysis).

[0049] S3, determining the required safety voltage value of the oil tank grounding system based on the calculation formulas of the touch voltage and the step voltage.

[0050] The calculation formulas of the touch voltage E touch50 and the step voltage E step50 are as follows:

[0051]

[0052]

[0053]

[0054] In the formula, ρ s is the resistivity of the upper soil, ρ is the resistivity of the lower soil, the unit is Ω·m; h s is the thickness of the upper soil, the unit is m; t is the fault current duration, the unit is s; C s is the surface attenuation coefficient;

[0055] The safety voltage value is the minimum value of the touch voltage E touch50 and the step voltage E step50 .

[0056] S4, according to the initially determined safety voltage value required by the oil tank grounding system, combining the three-dimensional model and the influence of seasonal environmental factors, and through the simulation analysis software, the working conditions of the oil tank grounding system under the influence of different seasonal environmental factors are analyzed and studied.

[0057] S5, simulate different improvement schemes by adjusting the object positioning and numerical setting of the simulation software, compare the simulation results corresponding to each improvement scheme, and obtain the optimal grounding arrangement scheme (the improvement scheme with the highest safe grounding voltage value), and output the simulation software result report.

[0058] S6, design the oil tank grounding system according to the result report, so that the grounding system design is economically optimal under the premise of meeting safety requirements.

[0059] Further, the oil tank grounding system design method considering the influence of seasonal environmental factors is suitable for oil tank areas in seasonal environments with variable or high altitudes, and can obtain an improvement scheme for the oil tank grounding grid in extremely harsh soil environments to meet the safety requirements of actual engineering.

[0060] II. Influence of seasonal environmental factors on oil tank grounding system

[0061] As shown in Table 1, the seasonal environmental factors considered in the present example include sunny day, rainy season and winter environment, and the influence of the improvement schemes of the two grounding grids on the oil tank grounding system is analyzed:

[0062] Table 1: Oil tank grounding grid parameters under the influence of different seasonal environmental factors

[0063]

[0064] 1. Influence of environment on oil tank grounding system

[0065] The sunny day environment uses a 200Ω·m uniform soil environment to simulate its influence on the grounding grid. The simulation research data is shown in Table 1, and the data in the table is the grounding resistance, contact voltage and step voltage value of the 100m*100m uniform grounding grid in this soil environment. This table data is used as a reference group to compare with the parameters under the influence of rainy season and winter environment, and summarize the influence law of the environment.

[0066] 2. Influence of environment on oil tank grounding system

[0067] The rainy season environment uses a double-layer soil environment to simulate its influence on the grounding grid, and the lower layer soil resistivity is not changed, the upper layer soil resistivity is valued in the range of 20-200Ω·m, and the thickness is valued in the range of 0-1.6m to simulate different rainfall in the rainy season.

[0068] As Figure 3 shown, the greater the thickness of the upper layer soil in the rainy season, the smaller the grounding resistance, and the influence intensifies with the decrease of the soil resistivity; the contact voltage and step voltage decrease with the increase of the thickness of the upper layer soil, and eventually reach a stable value.

[0069] 3. Effect of winter environment on oil tank grounding system

[0070] The winter environment, using a double-layer soil environment to simulate its effect on the grounding grid, sets the lower soil resistivity unchanged, the upper soil resistivity in the range of 200-8000 Ω·m, and the thickness in the range of 0-1.6 m, simulating the frozen soil environment in different periods of winter.

[0071] As shown in Figure 4 In winter, only when the upper soil thickness is greater than the grounding grid burial depth, the oil tank grounding system will be affected by the season, at this time, the grounding resistance increases rapidly and eventually tends to be flat with the increase of thickness; the touch voltage and the step voltage also appear a jump stage, which increases rapidly and eventually tends to be stable.

[0072] 4. Effect of improvement scheme on oil tank grounding system

[0073] The improvement scheme includes adding granite material on the surface of the oil tank area and improving the length of the deep well grounding electrode (vertical grounding body 2).

[0074] As shown in Table 1, adding granite material can significantly improve the touch voltage and step voltage limits, and simulation analysis shows that the scheme is feasible.

[0075] As shown in the following Table 2 data, the vertical grounding body 2 has a very obvious effect on reducing the touch voltage and step voltage, and using deep well grounding method can significantly improve the safety level of the oil tank grounding system.

[0076] The vertical grounding body 2 material in this example is a hot-dip galvanized angle steel with an angle of 50 mm x 50 mm x 5 mm.

[0077] Table 2, oil tank grounding grid parameters after vertical grounding body improvement

[0078]

[0079] III. Software analysis and verification

[0080] The simulation analysis software (SESCAD and MALZ modules in the power system grounding analysis software CDEGS) is used to simulate the oil tank grounding grid.

[0081] As shown in Figure 5 According to the oil tank grounding system engineering structure parameters and material electrical parameters and soil environment parameters, a three-dimensional model of the oil tank grounding grid and working environment is established, and the oil tank grounding system simulation analysis is carried out, and the result report output by the simulation software is as shown in Figure 6 The result report includes the length and number of the vertical grounding body 2 corresponding to the optimal improvement scheme.

[0082] Through simulation analysis, it can be seen that the scheme for improving the grounding system in the present research can achieve certain margin under the requirement of safe voltage, is more safe and reliable, and verifies the rationality of the technical scheme, and can be used as a reference scheme for actual engineering implementation.

[0083] In summary, by using the above-mentioned method for studying the seasonal factors on the performance of the oil tank grounding system, by comprehensively considering the tank farm environment, equipment and material factors, simulating the actual engineering scene, preliminarily determining the safety limit value of the grounding system based on the voltage calculation formula, and then further improving and optimizing the layout scheme of the oil tank grounding system in combination with the simulation software, the method for realizing the voltage reduction of the oil tank grounding system through the deep well grounding method can save the engineering land area, and is more stable, safe and reliable in work.

[0084] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for designing an oil tank grounding system considering the influence of seasonal environmental factors, characterized in that, The method comprises the following steps: S1, collecting and arranging engineering structure parameters and material electrical parameters of an oil tank grounding system and soil environment parameters of a location of the oil tank; S2, according to the engineering structure parameters and the material electrical parameters, performing three-dimensional modeling on the oil tank grounding system, and performing simulation analysis on the model by using a grounding analysis software; S3, determining a required safety grounding voltage value of the oil tank grounding system based on a contact voltage and a step voltage calculation formula; S4, based on the grounding analysis software, simulating influences of different seasonal environment factors on the contact voltage and the step voltage of the oil tank grounding system by changing the soil environment parameters; The different seasonal environment factors specifically include a sunny day environment, a rainy season environment and a winter environment; The sunny day environment adopts a 200Ω·m uniform soil environment to simulate influences of the sunny day environment on the oil tank grounding system; The rainy season environment adopts a double-layer soil environment to simulate influences of the rainy season environment on the oil tank grounding system, and the lower layer soil resistivity is not changed, the upper layer soil resistivity is valued in a range of 20-200Ω·m, and the thickness is valued in a range of 0-1.6m to simulate different rainfall amounts in the rainy season; The winter environment adopts a double-layer soil environment to simulate influences of the winter environment on the oil tank grounding system, and the lower layer soil resistivity is not changed, the upper layer soil resistivity is valued in a range of 200-8000Ω·m, and the thickness is valued in a range of 0-1.6m to simulate frozen soil environments in different periods of the winter; S5, improving the oil tank grounding system, comparing simulation results corresponding to the improvement schemes, obtaining an improvement scheme with the highest safety grounding voltage value as an optimal scheme, and outputting a result report by using the simulation software; The improvement schemes include adding granite materials on a ground surface of the oil tank area and changing numbers and lengths of vertical grounding bodies; S6, designing the oil tank grounding system according to the result report.

2. The method for designing grounding system of oil tank considering seasonal environmental factors according to claim 1, characterized in that In step S1, the engineering structure parameters include sizes of oil storage tanks, tank room heights, and tank room shell top structure sizes; the material electrical parameters include resistance parameters of steel plates of the oil storage tanks, steel bars and concrete of the tank room, and grounding materials; and the soil environment parameters include soil resistivity parameters and seasonal environment parameters of a location of the oil tank.

3. The method for designing grounding system of oil tank considering seasonal environmental factors according to claim 1, characterized in that In step S2, the oil tank grounding system includes horizontal grounding bodies (1) and vertical grounding bodies (2); the horizontal grounding bodies (1) form a 100m*100m uniform grounding net with a grid spacing of 10m and a buried depth of 0.6m; and numbers and length parameters of the vertical grounding bodies (2) are adjustable.

4. The method for designing grounding system of oil tank considering seasonal environmental factors according to claim 1, characterized in that In step S3, the contact voltage E touch50 and the step voltage E step50 are calculated according to the following formulas: In the formula, p s is the resistivity of the upper layer of soil, p is the resistivity of the lower layer of soil, and the unit is Ω·m; h s is the thickness of the upper layer of soil, and the unit is m; t is the duration of the fault current, and the unit is s; C s is the surface layer attenuation coefficient.

5. The method for designing grounding system of oil tank considering seasonal environmental factors according to claim 1, characterized in that In step S3, the safety grounding voltage value is the minimum value of the contact voltage and the step voltage.

6. The method for designing grounding system of oil tank considering seasonal environmental factors according to claim 1, characterized in that In step S6, the result report includes lengths and numbers of the vertical grounding bodies corresponding to the optimal scheme.

7. The method for designing grounding system of oil tank considering seasonal environmental factors according to claim 3, characterized in that, The horizontal grounding bodies (1) are made of hot-dip galvanized round steel with a diameter of 16mm; and the vertical grounding bodies (2) are made of hot-dip galvanized angle steel with an angle of 50mm*50mm*5mm.

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