Joint lightning protection safety protection method for offshore platform

Abstract

The invention discloses an offshore platform combined lightning protection safety protection method, which comprises the following steps of: establishing a lightning stroke model of ocean platform induction thunder by adopting a common mode method, determining the frequency and the intensity of lightning activities according to historical data of the lightning activities, and obtaining a peak value of transient current generated by the maximum lightning stroke; and calculating the impulse voltage at the expected lightning stroke position through the lightning current model, inputting the impulse voltage into an electrical equipment insulation model in the ocean platform, simulating the insulation resistance change of an insulation material in the electrical equipment under different lightning protection methods, and obtaining the lightning protection methods used by different electrical equipment. According to the invention, a traditional power grid lightning protection mode and an REO comprehensive resistance reduction grounding technology are combined, so that safe operation of the offshore platform in a thunder and lightning environment is ensured; the lightning protection effect is comprehensively evaluated through simulation analysis, and the effectiveness and stability of the lightning protection method are ensured.

Description

Technical Field

[0001] The present invention relates to a safety protection method for an offshore platform, and particularly to a lightning protection safety protection method for an offshore platform. Background Art

[0002] In response to environments such as offshore high-voltage co-construction platforms or drilling platforms that are vulnerable to lightning strikes, traditional lightning protection methods usually use lightning rods, lightning protection belts, etc. Although they can reduce the impact of lightning on the platform to a certain extent, limited by geological, site and other conditions, their effects are often not satisfactory. In recent years, the REO (rare earth element oxide) comprehensive resistance reduction grounding technology (specifically, see: Research Results of "Research and Application of REO Comprehensive Resistance Reduction Lightning Protection Technology" by the School of Energy, Power and Mechanical Engineering of North China Electric Power University on December 1, 2017 in Engineering Science and Technology II) as a new type of lightning protection technology, has received extensive attention due to its excellent electrical conductivity and resistance reduction effect. However, using the REO comprehensive resistance reduction grounding technology alone cannot fully meet the requirements of lightning protection safety for offshore platforms, and it is also necessary to combine traditional ground grid technology and lightning current models for combined protection. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a combined lightning protection safety protection method for an offshore platform. By using this method, the lightning protection effect of the offshore platform is optimized, and the safety protection performance is improved.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] A combined lightning protection safety protection method for an offshore platform of the present invention includes the following steps:

[0006] Step 1: Use the common mode method to establish a lightning strike model for induced lightning on an offshore platform, decompose the lightning strike transient process of induced lightning on the offshore platform, and use an exponential function to describe the impulse voltage at the position where lightning strikes occur. The formula of the lightning strike model is as follows:

[0007]

[0008] In the formula, V p (t) is the impulse voltage at the position where lightning strikes occur, t is the time when the lightning strike transient current rises, I p1 is the transient impulse current at the position where lightning strikes occur, R GND_i is the DC resistance of the grounding system, τ1 is the time constant of the lightning strike transient current rise, i is the i-th lightning strike, M is the total number of lightning strikes, and k is the lightning strike coefficient;

[0009] Step 2: Comprehensively collect relevant data on the environment where the offshore platform is located. Based on the historical data of lightning activities, including the frequency, intensity, and seasonal distribution of lightning occurrences, determine the frequency and intensity of lightning activities, and obtain the peak value of the transient current generated by the maximum lightning strike.

[0010] Step 3: Substitute the peak value of the lightning transient current collected in Step 2 into the lightning current model, and calculate the impulse voltage V p (t) at the expected lightning strike location.

[0011] Step 4: Based on the impulse voltage V p (t) obtained in Step 3, establish an insulation model for electrical equipment within the offshore platform. The insulation model for electrical equipment is:

[0012]

[0013] In the formula, R is the insulation resistance of the insulation material within the electrical equipment, ρ1 is the resistivity of the insulation material, d is the thickness of the insulation material, k1 and k2 are the environmental temperature and humidity correlation coefficients of the insulation material in the marine environment respectively, k3 and k4 are the environmental temperature and humidity correlation coefficients of the insulation material under breakdown conditions respectively, and ε is the dielectric constant of the insulation material.

[0014] Step 5: Through Step 4, establish a simulation model of the combined lightning protection system for the offshore platform in the power system electromagnetic transient simulation software, conduct a simulation analysis on the lightning protection effect of the offshore platform, input the impulse voltage V p (t) at the expected lightning strike location obtained in Step 3, and simulate the change in the insulation resistance of the insulation material within the electrical equipment under different lightning protection methods through the power system electromagnetic transient simulation software.

[0015] Step 6: Establish the grounding grid and REO comprehensive resistance reduction lightning protection system for the offshore platform lightning protection system, set the lightning protection threshold. When the insulation resistance of the insulation material within the electrical equipment is lower than the set grounding grid lightning protection threshold of 50 kΩ, use the grounding grid method for lightning protection. When the insulation resistance of the insulation material within the electrical equipment is within 50 kΩ ≤ lightning protection threshold ≤ 200 kΩ, use the REO comprehensive resistance reduction method for lightning protection. When the insulation resistance of the insulation material within the electrical equipment is higher than 200 kΩ, use the combined resistance reduction method of the grounding grid and REO comprehensive resistance reduction for lightning protection.

[0016] Step 7: Return to Step 1, readjust the transient impulse current I p1 at different lightning strike locations, recalculate the insulation resistance of the insulation material within different electrical equipment, and repeat Steps 1 to 6 to obtain the lightning protection methods used for different electrical equipment.

[0017] Step 8: Output the lightning protection schemes for all equipment of the offshore platform for actual use on the offshore platform.

[0018] The beneficial effects of the present invention are as follows:

[0019] By establishing an electric lightning current model and collecting environmental data, the method of the present invention realizes the accurate prediction and quantitative analysis of lightning activities, providing a scientific basis for the selection of lightning protection measures; combining traditional power grid lightning protection methods and REO comprehensive resistance reduction grounding technology ensures the safe operation of offshore platforms in a lightning environment; through simulation analysis, the lightning protection effect is comprehensively evaluated to ensure the effectiveness and stability of the lightning protection method; it has the advantages of high efficiency and reliability, providing a strong safety guarantee for the operation of offshore platforms. Brief Description of the Drawings

[0020] Figure 1 It is a flowchart of a combined lightning protection and safety protection method for an offshore platform of the present invention. Detailed Embodiments

[0021] The present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0022] As Figure 1 shown, a combined lightning protection and safety protection method for an offshore platform of the present invention includes the following steps:

[0023] Step 1: Use the common-mode method (specifically refer to: "Analysis Method of Direct Lightning Strike Protection for Ships Based on the Leader Development Model" in the 45th Volume, No. 7, 2024 of the Journal of Harbin Engineering University) to establish a lightning strike model for induced lightning on an offshore platform, decompose the lightning strike transient process of induced lightning on the offshore platform, and use an exponential function to describe the impulse voltage at the lightning strike location when lightning strikes. The formula of the lightning strike model is as follows:

[0024]

[0025] In the formula, V p (t) is the impulse voltage at the lightning strike location, t is the time when the lightning strike transient current rises, I p1 is the transient impulse current at the lightning strike location, R GND_i is the DC resistance of the grounding system (measurable), τ1 is the time constant of the lightning strike transient current rise, which is set according to the protection level of the offshore platform. When the protection level is level 1, it is set to 5 - 10 μs in 3D software. When the protection level is level 2, it is set to 0.25 - 1.5 μs in 3D software. i is the i-th lightning strike, M is the total number of lightning strikes, and k is the lightning strike coefficient (the values of k in different situations are specified in the "Code for Design of Lightning Protection of Buildings" GB50057 - 2010 in China).

[0026] Step 2: Comprehensively collect relevant data on the environment where the offshore platform is located. Based on historical data of lightning activities, including the frequency, intensity, and seasonal distribution of lightning occurrences, determine the frequency and intensity of lightning activities, and obtain the peak value of the transient current generated by the maximum lightning strike.

[0027] Step 3: Substitute the peak value of the lightning strike transient current collected in Step 2 into the lightning current model, and calculate the impulse voltage V(t) at the expected lightning strike position through calculation. The lightning strike intensity can be judged by the impulse voltage and can be used as a basis for formulating lightning protection strategies. p (t). The lightning strike intensity can be judged by the impulse voltage and can be used as a basis for formulating lightning protection strategies.

[0028] Step 4: Based on the impulse voltage V(t) at the expected lightning strike position obtained in Step 3, establish an insulation model for electrical equipment in the offshore platform. To prevent overvoltage breakdown or overcurrent damage of electrical equipment, the electrical equipment insulation model is: p (t), establish an insulation model for electrical equipment in the offshore platform. To prevent overvoltage breakdown or overcurrent damage of electrical equipment, the electrical equipment insulation model is:

[0029]

[0030] In the formula, R is the insulation resistance of the insulating material inside the electrical equipment, ρ1 is the resistivity of the insulating material, d is the thickness of the insulating material, k1 and k2 are the environmental temperature and humidity correlation coefficients of the insulating material in the marine environment respectively, k3 and k4 are the environmental temperature and humidity correlation coefficients of the insulating material under breakdown conditions respectively, k1, k2, k3, and k4 are obtained through insulation resistance tests and environmental temperature and humidity correlation tests, and ε is the dielectric constant of the insulating material, which is obtained by looking up the material handbook.

[0031] Step 5: Through Step 4, establish a simulation model of the combined lightning protection system for the offshore platform in the power system electromagnetic transient simulation software, conduct a simulation analysis of the lightning protection effect of the offshore platform, input the impulse voltage V(t) at the expected lightning strike position obtained in Step 3, and simulate the change of the insulation resistance of the insulating material inside the electrical equipment under different lightning protection methods through the power system electromagnetic transient simulation software; p (t), and simulate the change of the insulation resistance of the insulating material inside the electrical equipment under different lightning protection methods through the power system electromagnetic transient simulation software;

[0032] Step 6: Establish a grounding grid and REO comprehensive resistance reduction lightning protection system for the offshore platform lightning protection system, set the lightning protection threshold. When the insulation resistance of the insulating material inside the electrical equipment is lower than the set grounding grid lightning protection threshold (such as it can be set to 50 kΩ), use the grounding grid method for lightning protection. When the insulation resistance of the insulating material inside the electrical equipment is between 50 kΩ ≤ lightning protection threshold ≤ 200 kΩ, use the REO comprehensive resistance reduction method for lightning protection. When the insulation resistance of the insulating material inside the electrical equipment is higher than 200 kΩ, use the combined resistance reduction method of the grounding grid and REO comprehensive resistance reduction for lightning protection;

[0033] Step 7: Return to Step 1 and readjust the transient impulse current I at different lightning strike positions. p1, recalculate the insulation resistance of the insulating materials in different electrical equipment, and repeat steps 1 to 6 to obtain the lightning protection methods used by different electrical equipment.

[0034] Step 8: Output the lightning protection schemes for all the equipment on the offshore platform for actual use on the offshore platform.

Claims

1. A combined lightning protection method for offshore platforms, characterized in that The following steps are involved: Step 1: Use the common mode method to establish the lightning strike model of the offshore platform induced lightning, decompose the transient process of the offshore platform induced lightning, and use the exponential function to describe the impulse voltage at the location of the lightning strike when the lightning strike occurs. The formula of the lightning strike model is as follows: Where V p (t) is the impulse voltage at the location struck by lightning, t is the time it takes for the instantaneous current to rise during lightning strike, I p1 is the transient impulse current at the location struck by lightning, R GND_i is the DC resistance of the grounding system, τ1 is the time constant of the instantaneous current rise of lightning strike, i is the i-th lightning strike, M is the total number of lightning strikes, and k is the lightning strike coefficient; Step 2: Comprehensively collect relevant data on the environment of the offshore platform, determine the frequency and intensity of lightning activity based on historical data on lightning activity, including the frequency, intensity, and seasonal distribution of lightning, and obtain the peak value of the transient current generated by the maximum lightning strike; Step 3: Substitute the peak value of the lightning transient current collected in step 2 into the lightning current model, and calculate the expected impulse voltage V at the lightning strike location. p (t); Step 4: The impulse voltage V at the expected lightning strike position obtained in step 3 p (t) Establish the insulation model of electrical equipment in the offshore platform. The insulation model of electrical equipment is: Where R is the insulation resistance of the insulating material in the electrical equipment, ρ1 is the resistivity of the insulating material, d is the thickness of the insulating material, k1 and k2 are the correlation coefficients of the ambient temperature and humidity of the insulating material under the marine environment, k3 and k4 are the correlation coefficients of the ambient temperature and humidity of the insulating material under the breakdown condition, and ε is the dielectric constant of the insulating material; Step 5: Establish a joint lightning protection system simulation model of the offshore platform in the power system electromagnetic transient simulation software through step 4, simulate and analyze the lightning protection effect of the offshore platform, and input the impulse voltage V at the expected lightning strike position obtained in step 3. p (t) Simulate the insulation resistance changes of insulating materials in electrical equipment under different lightning protection methods through power system electromagnetic transient simulation software; Step 6: Establish the grounding grid and REO comprehensive resistance reduction lightning protection system of the offshore platform lightning protection system, set the lightning protection threshold, when the insulation resistance of the insulating material in the electrical equipment is lower than the set grounding grid lightning protection threshold of 50kΩ, use the grounding grid to avoid lightning, when the insulation resistance of the insulating material in the electrical equipment is 50kΩ≤lightning protection threshold≤200kΩ, use REO comprehensive resistance reduction to avoid lightning, when the insulation resistance of the insulating material in the electrical equipment is higher than 200kΩ, use the grounding grid and REO comprehensive resistance reduction combined resistance reduction method to avoid lightning; Step 7: Return to step 1 and readjust the transient impulse current I at different lightning strike locations. p1 , recalculate the insulation resistance of the insulating materials in different electrical equipment, repeat steps 1 to 6, and obtain the lightning protection methods used by different electrical equipment; Step 8: Output the lightning protection scheme for all equipment on the offshore platform for actual use on the offshore platform.

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