A buried pipeline overvoltage protection method and system based on power transmission line layout optimization

Abstract

This invention relates to the field of oil and gas pipeline planning technology, and discloses a method and system for overvoltage protection of buried pipelines based on power transmission line layout optimization. The method includes collecting power transmission line parameters and buried oil and gas pipeline parameters within a target area; identifying key layout parameters that significantly affect the induced voltage of the pipeline from the design parameters of the power transmission lines; calculating the sensitivity coefficient of each layout parameter change to the maximum induced voltage of the pipeline using a parameter perturbation method and a three-dimensional electromagnetic coupling model; establishing a multi-objective layout optimization mathematical model with the objective function of minimizing the maximum induced voltage along the pipeline, and constraints such as the electrical performance constraints, structural safety constraints, engineering economic constraints, and the pipeline safety voltage threshold; and achieving a scientific quantitative determination of the electromagnetic environment impact of high-voltage power transmission lines on oil and gas pipelines. During the planning and design phase, electromagnetic interference is reduced through line layout optimization, thus reducing the cost of passive protection on the pipeline side.

Description

Technical Field

[0001] This invention relates to the field of oil and gas pipeline planning technology, and in particular to a method, system, equipment and medium for overvoltage protection of buried pipelines based on power transmission line layout optimization. Background Technology

[0002] With the construction and development of the national energy network, high-voltage overhead transmission lines and long-distance buried oil and gas pipelines inevitably have numerous spatial intersections or parallel proximity sections. The time-varying electromagnetic fields (including steady-state power frequency fields and transient electromagnetic fields) generated during the operation of transmission lines can induce longitudinal voltages and circulating currents in adjacent buried metal pipelines through electromagnetic induction, capacitive coupling, and conductive coupling. These induced voltages can lead to pipeline corrosion breakdown, accelerated corrosion, electric shock risks, equipment damage, and even, in extreme cases, fires or explosions.

[0003] Currently, most protective measures for this problem focus on the pipeline side and are passive or remedial technologies, such as grounding drainage, segmented insulation, and shielding. These methods have shortcomings such as high investment costs, complex maintenance, and difficulty in eradicating risks. Furthermore, there is a lack of a systematic approach to proactively optimize the layout during the transmission line planning and design phase, resulting in a lack of quantitative basis for protection decisions and making it difficult to control risks at their source. Summary of the Invention

[0004] This invention provides a method, system, equipment, and medium for overvoltage protection of buried pipelines based on power transmission line layout optimization, in order to solve the above-mentioned technical problems in the prior art.

[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or to describe the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0006] According to a first aspect of the present invention, a method for overvoltage protection of buried pipelines based on power transmission line layout optimization is provided.

[0007] In one embodiment, the buried pipeline overvoltage protection method based on transmission line layout optimization includes: S1. Basic Data Acquisition and 3D Scene Modeling: Collect parameters of power transmission lines, buried oil and gas pipelines, spatial relative position information of power transmission lines and buried oil and gas pipelines, and soil environmental parameters in the target area. Organize them into a dataset and construct an initial 3D electromagnetic coupling model containing power transmission lines, buried pipelines and surrounding soil environment through the dataset. S2. Identification and Sensitivity Measurement Analysis of Key Layout Parameters: From the design parameters of the transmission line, key layout parameters that significantly affect the induced voltage of the pipeline are identified. The sensitivity coefficient of each layout parameter change to the maximum induced voltage of the pipeline is calculated by using the parameter perturbation method and the three-dimensional electromagnetic coupling model. S3. Establish a multi-constraint layout optimization mathematical model: With minimizing the maximum induced voltage along the pipeline as the objective function, the key layout parameters identified in step S2 as optimization variables, and the electrical performance constraints, structural safety constraints, engineering economic constraints, and pipeline safety voltage threshold as constraints, a multi-objective layout optimization mathematical model is established. S4. Optimization and scheme generation based on intelligent algorithms: The optimization model established in step S3 is solved using a genetic algorithm to obtain several Pareto optimal transmission line layout schemes. For each scheme, the three-dimensional electromagnetic coupling model is used for verification calculation to ensure that it meets all constraints. S5. Protection Effect Evaluation and Scheme Recommendation: For each optimization scheme generated in step S4, evaluate its overvoltage suppression effect on the pipeline under typical working conditions, and conduct a comprehensive evaluation in combination with engineering modification costs and implementation difficulty, and output the recommended optimal layout optimization scheme and the corresponding expected induced voltage level of the pipeline.

[0008] The above technical solution enables the scientific quantification of the electromagnetic environment impact of high-voltage transmission lines on oil and gas pipelines. Standardized data processing ensures input accuracy, while optimization algorithms enable precise decision-making, taking into account constraints related to safety, electrical systems, structure, and economy, and providing a Pareto-optimal solution set.

[0009] Furthermore, the initial three-dimensional electromagnetic coupling model, including the transmission line, buried pipeline, and surrounding soil environment, in step S1 includes: Data preprocessing: unify all spatial coordinates to a coordinate system, unify them to the International System of Units (SI), remove outliers, and fill in missing values ​​using interpolation. Model selection: Professional multiphysics simulation software is used, which supports multiphysics coupling calculations of electromagnetic fields, circuits, and thermal fields; Establish geometric models: Using the collected data, model the power transmission lines, buried pipelines, soil environment, and spatial relationships respectively; Material property assignment: Assign material properties and typical values ​​to conductors, pipes, anti-corrosion coatings, soil, and air; Physics field settings: Set the excitation source, electromagnetic field module, and boundary conditions respectively; Mesh generation: Free tetrahedral mesh is used to adapt to complex geometries; Theoretical verification: The induced voltage in the pipeline under a simple scenario was calculated using the Nelson formula. The error was compared with the simulation results of the model. The error should be ≤5%. Typical sections that have been built were selected, and the induced voltage and electric field strength of the pipeline were measured. The average error was compared with the simulation results. The error should be ≤8%. If the error exceeds the tolerance, the material parameters or boundary conditions should be adjusted.

[0010] Furthermore, the key layout parameters in step S2 include at least: conductor phase sequence arrangement, horizontal distance of each phase conductor relative to the conduit, conductor suspension height above the ground, and tower location. Furthermore, the parameter perturbation method includes the following steps: S21. Determine the layout parameters to be analyzed and their range of variation: Based on industry design regulations and engineering practice experience, select layout parameters that have a significant impact on pipeline induced voltage and are adjustable in engineering. The selection criteria include: significant electromagnetic impact, engineering adjustability, economic feasibility, and safety compliance. S22, Parameter Discretization Sampling: Discretize each layout parameter within its range of variation using an equal-interval sampling method; S23. Single-parameter disturbance simulation calculation: Based on the three-dimensional electromagnetic coupling model, each layout parameter is set as its discrete sampling value in turn, while keeping other parameters as the reference value, and electromagnetic field simulation calculation is performed to extract the maximum value of induced voltage along the pipeline. S24. Calculate the sensitivity coefficient: Based on the simulation results, calculate the sensitivity coefficient of each layout parameter to the maximum induced voltage of the pipeline; S25. Sensitivity processing of discrete parameters: For discrete layout parameters, the range method is used to quantify their sensitivity. S26. Batch Automated Calculation Process: Build a computing system with a three-tier architecture of client-server-computing cluster to realize batch automated simulation and sensitivity calculation of parameters; S27. Sensitivity Ranking and Visualization: Based on the calculated sensitivity coefficients, the layout parameters are ranked and a sensitivity ranking chart, parameter-voltage response curve, Pareto front plot, and three-dimensional sensitivity distribution cloud map are generated.

[0011] Furthermore, in step S24, the sensitivity coefficient Defined as: ; in, : The change in the maximum induced voltage of the pipeline; Layout parameters The change in; To facilitate comparison of the effects of parameters with different dimensions, a normalized sensitivity coefficient is used:

[0012] Furthermore, the establishment of the multi-objective layout optimization mathematical model in step S3 includes: S31. Establish a mathematical model for optimizing the layout of power transmission lines, transforming the engineering problem into a mathematical optimization problem; S32. Determine key variables based on sensitivity analysis: Based on the sensitivity analysis results of step S2, select layout parameters that have a significant impact on pipeline induced voltage and are adjustable in engineering as optimization variables. S33. Objective function construction: Construct a dual objective function with minimizing the maximum induced voltage in the pipeline as the primary objective and the cost of line modification as the secondary objective; S34. Constraint Construction: Construct multiple types of constraints, including electrical performance constraints, structural safety constraints, engineering economic constraints, and pipeline safety voltage thresholds. S35. Multi-objective processing strategy: Use the weighted sum method to transform multi-objective optimization problems into single-objective or hierarchical optimization problems; S36. Organize into a mathematical model: Integrate the objective function and constraints into a complete mathematical optimization model; S37. Determining the parameters of the model: Determine the values ​​of various parameters in the model based on the actual engineering situation; S38. Implement mathematical models using Python code: Write a calculation program for the optimization model to achieve automated modeling and solving; S39. Model Validation and Sensitivity Analysis: Verify the accuracy of the model through random sampling and full 3D simulation comparison, and conduct parameter sensitivity analysis; S310. Model Output and Application: Output optimization results, including the Pareto optimal solution set, the objective function values ​​and constraint satisfaction of each scheme, and provide a visualization report.

[0013] Furthermore, the multi-objective layout optimization mathematical model established in step S3 is expressed as follows:

[0014] in, To optimize the variable vector, its components Key layout parameters that significantly affect the induced voltage of the pipeline are identified in step S2, including but not limited to the conductor phase sequence arrangement, the horizontal distance of each phase conductor relative to the pipeline, the conductor suspension height to the ground, and the tower location. The objective function vector represents the maximum induced voltage along the pipeline, which is calculated using the three-dimensional electromagnetic coupling model. : is the economic objective function, representing the cost of line modification caused by the layout adjustment; These inequality constraints together constitute the electrical performance constraints, structural safety constraints, engineering economic constraints, and pipeline safety voltage thresholds for transmission lines. : These are the lower and upper bound vectors of the optimization variable x, respectively, which are determined by engineering design specifications, safety standards, and engineering economic requirements.

[0015] Furthermore, the constraints include: Electrical constraints: The power frequency electric field strength and radio interference level of the line shall not exceed the standard limits; the changes in the inductance and capacitance parameters of the line shall be within the allowable range to ensure the correct operation of the relay protection. Structural constraints: Conductor sag, tower load, and safety distance meet the requirements of the regulations; Economic constraints: The additional costs caused by optimization, such as changes in route length, increased number of poles and towers, and use of special poles and towers, shall not exceed the budget threshold; Safety constraints: The induced voltage of the optimized pipeline must be lower than the breakdown voltage of its anti-corrosion layer or the safety limit specified in relevant standards.

[0016] Furthermore, the induced voltage in the pipeline was measured before and after the line was put into operation, and the results were compared with the simulation results to correct the model parameters.

[0017] In one embodiment, an overvoltage protection system for buried pipelines based on transmission line layout optimization is proposed, comprising: Data acquisition and modeling module: used to input or import basic data of transmission lines, pipelines, and environment, and automatically build an initial three-dimensional electromagnetic coupling simulation model; Sensitivity Analysis Module: This module is used to automatically identify key layout parameters from line parameters, perform batch calculations by calling simulation models, complete sensitivity analysis of each parameter, and output a sensitivity ranking report. Optimization model building module: This module automatically transforms engineering problems into mathematical optimization models based on user-defined optimization objectives and various constraints. Optimization Solving Engine Module: Integrates multiple optimization algorithms to automatically solve the constructed optimization model and output multiple feasible optimization solutions and their objective function values; Scheme Evaluation and Decision Support Module: This module performs electromagnetic simulation verification on the schemes output by the optimization solution engine, and combines the cost estimation model to conduct a comprehensive technical and economic evaluation of each scheme, providing decision support in the form of charts and reports. Database and knowledge base: Used to store basic parameters, simulation results, optimization schemes, historical cases, and knowledge such as line design specifications and pipeline safety standards, providing data support for each module; The system adopts a B / S architecture. The front end uses the Vue.js framework to provide a visual operation interface, while the back end is developed using Python. It integrates the APIs of commercial simulation software such as COMSOL or ANSYS for electromagnetic calculations. The optimization algorithm is based on PyGMO or a custom implementation. The system supports multi-user collaboration and project management.

[0018] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: This invention establishes a comprehensive technical system that scientifically quantifies the impact of high-voltage transmission lines on the electromagnetic environment of oil and gas pipelines. During the planning and design phase, electromagnetic interference is reduced through line layout optimization, decreasing passive protection costs on the pipeline side. Layout parameters and pipeline voltage quantification models, combined with optimization algorithms, enable precise decision-making, taking into account constraints related to safety, electrical systems, structure, and economy. This provides a Pareto optimal solution set and integrates data management, simulation analysis, optimization calculation, and evaluation decision-making, thereby improving the efficiency of engineering applications.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0021] Figure 1 This is a flowchart illustrating an overvoltage protection method for buried pipelines based on power transmission line layout optimization, according to an exemplary embodiment. Figure 2 This is a flowchart illustrating a method for calculating the sensitivity coefficient of the maximum induced voltage of a pipeline to changes in various layout parameters, according to an exemplary embodiment. Figure 3 This is one of the flowcharts illustrating the process of establishing a multi-objective layout optimization mathematical model; Figure 4 This is the second schematic diagram of the process for establishing a multi-objective layout optimization mathematical model; Figure 5 This is a structural block diagram illustrating an overvoltage protection system for buried pipelines based on power transmission line layout optimization, according to an exemplary embodiment. Detailed Implementation

[0022] The following description and accompanying drawings fully illustrate specific embodiments described herein to enable those skilled in the art to practice them. Some embodiments may include or substitute parts and features of other embodiments. The scope of the embodiments herein encompasses the entire scope of the claims and all available equivalents thereof. Throughout this document, the terms “first,” “second,” etc., are used only to distinguish one element from another without requiring or implying any actual relationship or order between the elements. Indeed, a first element can also be referred to as a second element, and vice versa. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure, apparatus, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a structure, apparatus, or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the structure, apparatus, or device that includes said element. The various embodiments described herein are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0023] The terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used in this document to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings. They are used solely for the convenience of describing the document and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description herein, unless otherwise specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two elements; they can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0024] In this document, unless otherwise stated, the term "multiple" means two or more.

[0025] In this article, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0026] In this article, the term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0027] It should be understood that although the steps in the flowchart are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order constraint on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the diagram may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0028] The modules in the apparatus or system of this application can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0029] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0030] Figures 1-4 An embodiment of the present invention is shown, which is a method for overvoltage protection of buried pipelines based on power transmission line layout optimization. In this embodiment, a planning scenario in which a 220kV high-voltage power transmission line and an X80 gas transmission pipeline are laid in parallel is applied.

[0031] In this optional embodiment, the buried pipeline overvoltage protection method based on transmission line layout optimization includes: S1. Basic Data Acquisition and 3D Scene Modeling: Obtain transmission line parameters within the target area from GIS and design drawings: voltage level, conductor type / number of splits / arrangement, span, height above ground, rated current, short-circuit current level (with a clearly defined calculation benchmark, such as 1000MVA), and operating frequency. Data sources include design drawings, short-circuit calculation reports, and industry standards. Parameter errors are required to be ≤±2%, and conductor height must be verified through on-site spot checks.

[0032] Buried oil and gas pipeline parameters include: material (steel grade, electrical conductivity, magnetic permeability), pipe diameter, wall thickness, burial depth, type and thickness / resistivity of anti-corrosion coating, and cathodic protection parameters (potential, current). Data sources include design drawings, material certificates, anti-corrosion coating test reports, and cathodic protection plans. Burial depth error must be ≤ ±5cm, and material parameters must be 100% accurate. Spatial relative position information of power transmission lines and buried oil and gas pipelines: including the length of parallel / overlapping sections of the lines and pipelines, minimum spatial clearance (from the lowest point of the conductor to the highest point of the pipeline), intersection angle, and three-dimensional coordinates (towers, pipeline turning points). Data sources include GIS data, GNSS field measurements (accuracy ≥ 1cm), and laser ranging, with clearance error required to be ≤ ±10cm and coordinate error ≤ ±0.5m.

[0033] Soil environmental parameters include soil stratified resistivity (measured using the four-electrode method to the pipe burial depth), soil moisture, topographic slope, and meteorological data (temperature and precipitation). Data sources include field sampling, environmental monitoring reports, and meteorological station data. The soil resistivity measurement error is required to be ≤±5%.

[0034] The above datasets are compiled and organized into a dataset. An initial three-dimensional electromagnetic coupling model, including transmission lines, buried pipelines, and the surrounding soil environment, is constructed using this dataset. Specifically, this includes: S11. Standardization: Unify all parameters to the International System of Units (SI); coordinate system to WGS84; standardize text descriptions; normalize proportional parameters (such as humidity) to the [0,1] range to ensure data format uniformity.

[0035] S11. Data preprocessing: Apply the 3σ criterion to remove outliers (such as unreasonable short-circuit current data), directly correct or remove logically erroneous data (such as negative parameters), supplement missing soil parameters using Kriging interpolation, and verify data consistency (error ≤ 1%).

[0036] S13. Association Mapping: Using "spatial coordinates + segment number" as key fields, a spatial relationship database is constructed using PostGIS to achieve accurate spatial association and rapid query analysis between line segments and pipeline segments, providing data association support for subsequent mechanism analysis and initial three-dimensional electromagnetic coupling model.

[0037] S14. Software platform selection: COMSOL Multiphysics 6.0 is preferred because it has powerful multiphysics coupling capabilities and a flexible user interface, which can accurately simulate the complex electromagnetic coupling process of "lines, pipes, and soil".

[0038] S15. Establish a geometric model: Based on the actual engineering situation, reasonable simplification is made. The wires are set as ideal conductors, the pipes are made of uniform steel material, and the soil is a uniform semi-infinite medium. Electromagnetic reflection of non-critical metal components is ignored, and the calculation efficiency is improved while ensuring the calculation accuracy.

[0039] Modeling steps: Geometry Import: Import the pre-processed spatial coordinate data of the lines and pipelines (supports DXF format) into the software to create accurate cylindrical conductors, pipeline models with anti-corrosion coatings, and soil-air calculation domains.

[0040] Material assignment: Based on the collected parameters, precise electromagnetic property parameters are assigned to conductors (aluminum / copper, high conductivity), pipes (steel, μr≈100), anti-corrosion layers (such as 3PE, εr≈2.5, high resistivity), soil (custom resistivity), etc.

[0041] S16. Physical field settings: The steady-state field setting is "Time-Harmonic Electromagnetic Field" (50Hz), which applies a three-phase sinusoidal current excitation (phase difference 120°) to the conductor; the transient field setting is "Transient Electromagnetic Field", which applies a pulse current (short circuit) or pulse voltage (operation) excitation; the "Electromagnetic Field-Circuit Coupling" module is enabled to connect the pipeline to the equivalent cathodic protection circuit to simulate the actual operating scenario.

[0042] S17. Mesh generation strategy: Adaptive free tetrahedral mesh is adopted to refine the mesh with high density in the area adjacent to the line and pipeline (<5m), the anti-corrosion layer, and the surface of the conductor (mesh size ≤0.2m, locally ≤0.05m), while the far field area is coarsened to balance computational efficiency while ensuring computational accuracy.

[0043] Boundary and Coupling Definitions: The spatial boundary is set as a cuboid computational domain, and absorbing boundary conditions are set at the boundary to reduce reflection; the interface satisfies the rules of tangential continuity and normal abrupt change of electromagnetic field; the interaction relationships of electromagnetic induction, capacitive coupling and conduction coupling are clearly defined to ensure the accuracy of the physical meaning of the model.

[0044] •S18. Theoretical verification: Select a typical cross-section and use the classical Nelson formula to calculate the theoretical value of the induced voltage in the pipeline. Compare it with the steady-state calculation results of the model and adjust the parameters to make the error ≤5%.

[0045] In the specific implementation process, it is also necessary to conduct actual measurement verification: set up measuring points in similar engineering sections that have been built, measure the induced voltage and electric field strength of the pipeline, compare them with the model simulation results, optimize the model parameters until the average error is ≤8%, and ensure the reliability and engineering applicability of the model.

[0046] S2. Identification and Sensitivity Measurement Analysis of Critical Layout Parameters: From the design parameters of transmission lines, critical layout parameters that significantly affect the induced voltage in pipelines are identified, specifically including: The Analytic Hierarchy Process (AHP) was used to invite 3-5 industry experts in electromagnetics, power systems, and pipeline engineering to score and determine the weights of four core factors: Line parameters (weight ~0.35): including voltage level, current magnitude, conductor phase sequence arrangement and splitting method.

[0047] Pipeline parameters (weight ~0.25): including burial depth, pipe diameter, and insulation performance of the anti-corrosion layer.

[0048] Spatial location parameters (weight ~0.25): including the horizontal distance, parallel length, crossing angle, conductor suspension height above the ground, and tower position of each phase conductor relative to the pipeline.

[0049] Environmental parameters (weight ~0.15): including soil resistivity and humidity.

[0050] Using the parametric perturbation method and the three-dimensional electromagnetic coupling model, the sensitivity coefficients of each layout parameter change to the maximum induced voltage of the pipeline are calculated, specifically including: S21. Determine the layout parameters to be analyzed and their range of variation: Based on industry design specifications and engineering practice experience, select layout parameters that significantly affect the induced voltage of the pipeline and are adjustable in engineering practice. Selection principles include: Significance of electromagnetic effects: Based on electromagnetic field theory, key geometric parameters affecting the strength of inductive coupling; Engineering adjustability: Parameters that allow for adjustment in the planning and design; Economic feasibility: Adjusted costs are within the limits of the project budget; Safety compliance: The adjusted system still meets the relevant safety standards.

[0051] For example: horizontal relative offset, height of side phase conductors, height of middle phase conductors, phase sequence arrangement, conductor phase distance and crossing angle; Taking the "horizontal relative offset" parameter as an example, the process for determining its range is as follows: Lower limit determined: Based on the constraint of the line corridor width, the line centerline is allowed to be offset by a maximum of 15m towards the pipeline side to avoid affecting other facilities; Upper limit determined: a maximum allowable offset of 15m away from the pipeline side to control the path growth within 5%; Reference value: The original design offset is 0m.

[0052] S22. Parameter Discretization Sampling: An equidistant sampling method is used, with 5 discrete points evenly selected for each parameter within its value range. Sampling point calculation formula:

[0053] Where N=5 is the number of sampling points, This represents the minimum value of the i-th parameter (the lower limit of the parameter's range of variation), and vice versa. It is the maximum value of the i-th parameter (the upper limit of the parameter's range of variation).

[0054] S23. Single-parameter disturbance simulation calculation: Baseline Model Loading: Load the pre-built 3D electromagnetic coupling baseline model (.mph file) of "220kV Line-X80 Pipeline" from COMSOL.

[0055] Parameter setting loop: For each parameter to be analyzed, set its sampling point value in turn, while keeping other parameters as the baseline value.

[0056] Electromagnetic field calculation: Analysis of harmonic electromagnetic fields during operation, frequency 50Hz, to solve for the induced voltage distribution along the pipeline.

[0057] Result Extraction: The induced voltage at 300 equally spaced points along the pipeline was extracted, and the maximum value was calculated. .

[0058] Data Record: Records the maximum value corresponding to the current parameter value. Information such as computation time and convergence status.

[0059] S24. Calculate the sensitivity coefficient: Based on the simulation results, calculate the sensitivity coefficient of each layout parameter to the maximum induced voltage in the pipeline. Defined as:

[0060] in, : The change in the maximum induced voltage of the pipeline; Layout parameters The change in; To facilitate comparison of the effects of parameters with different dimensions, a normalized sensitivity coefficient is used:

[0061] S25. Sensitivity processing of discrete parameters: The sensitivity of discrete parameters is quantified using the range method; S26. Batch Automated Calculation Process: The batch calculation system adopts a three-tier architecture of client-server-computing cluster. The client layer consists of a web interface used for task submission and result viewing. Server layer: task scheduling, data management, and result processing; Computing cluster layer: 4 computing nodes, each node is configured with 20 CPU cores, dedicated to performing COMSOL simulations; S27. Sensitivity Ranking and Visualization: Establish a comprehensive scoring system with four dimensions, such as voltage sensitivity, improvement potential, engineering feasibility, and cost impact, and conduct comprehensive scoring for each parameter, including phase sequence arrangement, horizontal offset, cross angle, middle phase height, side phase height, and phase distance.

[0062] For example: The system automatically generates the following visualizations: Sensitivity ranking bar chart: intuitively displays the overall score ranking of each parameter.

[0063] Parameter-voltage response curve: shows the trend of how changes in various parameters affect the voltage.

[0064] Pareto front plot (for multiple parameter combinations): shows the voltage-cost trade-offs for different parameter combinations.

[0065] Three-dimensional sensitivity distribution cloud map: showing the voltage response surface when two parameters change simultaneously.

[0066] like: Overall sensitivity score (out of 10) Phase sequence arrangement ██████████ 7.06 Horizontal offset ████████ 6.22 Cross angle ██████ 5.20 Mid-phase height █████ 4.67 Phase height ████ 4.28 Interphase distance ███ 3.60 0 5 10 S3. Establish a multi-constraint layout optimization mathematical model: With minimizing the maximum induced voltage along the pipeline as the objective function, the key layout parameters identified in step S2 as optimization variables, and the electrical performance constraints, structural safety constraints, engineering economic constraints, and pipeline safety voltage threshold as constraints, a multi-objective layout optimization mathematical model is established. The step S3 of establishing a multi-objective layout optimization mathematical model includes: S31. Establish a mathematical model for optimizing the layout of power transmission lines, transforming the engineering problem into a mathematical optimization problem. The multi-objective layout optimization mathematical model established in step S3 is expressed as follows:

[0067] in, To optimize the variable vector, its components Key layout parameters that significantly affect the induced voltage of the pipeline are identified in step S2, including but not limited to the conductor phase sequence arrangement, the horizontal distance of each phase conductor relative to the pipeline, the conductor suspension height to the ground, and the tower location. The objective function vector represents the maximum induced voltage along the pipeline, which is calculated using the three-dimensional electromagnetic coupling model. : is the economic objective function, representing the cost of line modification caused by the layout adjustment; These inequality constraints together constitute the electrical performance constraints, structural safety constraints, engineering economic constraints, and pipeline safety voltage thresholds for transmission lines. : These are the lower and upper bound vectors of the optimization variable x, respectively, which are determined by engineering design specifications, safety standards, and engineering economic requirements.

[0068] To address the electromagnetic interference problem between power transmission lines and pipelines, a dual-objective optimization model is adopted:

[0069] In the formula: Maximum induced voltage in the pipeline (safety target); Line upgrade cost (economic target); It contains 10 inequality constraints, covering four aspects: electrical, structural, economic, and safety.

[0070] S32. Key variables identified based on sensitivity analysis: Based on the sensitivity analysis results of step S2, select optimization variables according to the following principles: High sensitivity principle: Select parameters with normalized sensitivity > 0.2; The principle of engineering adjustability: Select parameters that are easy to adjust in actual engineering projects; Independence principle: Avoid using highly correlated parameters as variables simultaneously; Cost-benefit principle: Adjust parameters to match costs with improvements.

[0071] For example: Based on the sensitivity ranking of S2 and the above principles, four key parameters are selected as optimization variables:

[0072] Variable vector: .

[0073] Note: The edge phase height and phase-to-phase distance are not included in the optimization variables due to their low sensitivity and correlation with the middle phase height, and are maintained at the baseline values.

[0074] S33. Construction of the objective function: Safety objective: Minimize the maximum induced voltage in the pipeline. . The induced voltage distribution along the pipeline was calculated using a COMSOL three-dimensional electromagnetic model. Take N=100 calculation points at equal intervals along the length of the pipeline; Extract the maximum absolute value.

[0075] S34. Constraint Construction: The constraints include: Electrical constraints: The power frequency electric field strength and radio interference level of the line shall not exceed the standard limits; the changes in the inductance and capacitance parameters of the line shall be within the allowable range to ensure the correct operation of the relay protection. Structural constraints: Conductor sag, tower load, and safety distance meet the requirements of the regulations; Economic constraints: The additional costs caused by optimization, such as changes in route length, increased number of poles and towers, and use of special poles and towers, shall not exceed the budget threshold; Safety constraints: The induced voltage of the optimized pipeline must be lower than the breakdown voltage of its anti-corrosion layer or the safety limit specified in relevant standards.

[0076] Among these, for electrical constraints, electric field strength constraints include: In the formula, Calculations based on electromagnetic model (Maximum field strength offline).

[0077] Radio interference constraints: In the formula, (Good weather), calculations are performed using empirical formulas: In the formula , , This represents the distance between the traverse line and the measurement point.

[0078] For structural constraints, the ground distance constraint is: ,in (Residential area), conductor height (fixed), ; Safety clearance constraints: ,in, Minimum distance between the line and the pipeline, Given a combination of layout parameters x, this represents the minimum spatial distance between the conductors of the power transmission line and the buried oil and gas pipeline.

[0079] Tower load constraints: ,in, Design loads for the towers, It is the maximum combined load value that the tower can withstand under the optimized layout parameters x, and it consists of the following three components: Wind load: The horizontal load generated by wind pressure on conductors and tower structures.

[0080] Ice load: The load generated by the combined weight of ice on the conductor and wind pressure under icing conditions.

[0081] Additional load caused by parameter adjustment: The amount of load change caused by changes in line layout parameters (such as horizontal offset, suspension height, etc.).

[0082] Regarding economic constraints, the path growth constraint is: ,in, (Maximum growth rate of 5%).

[0083] Cost budget constraints: ,in, (This is the budget for this project).

[0084] For safety constraints, the steady-state voltage constraint is: ,in, .

[0085] Transient voltage constraints: ,in, (Impact withstand voltage of anti-corrosion layer). Pipeline transient overvoltage peak value = fault amplification factor × pipeline steady-state maximum induced voltage.

[0086] S35. Multi-target processing strategy: targeting security objectives and economic goals To address the conflicting characteristics, the following strategy is adopted: Pareto optimization: As the primary method, it searches for the Pareto front; ε-constraint method: Transforms economic objectives into constraints, focusing on safety optimization; Weighted sum method: used as an auxiliary method for specific preference scenarios; S36. Organize the objective function and constraints into a complete mathematical optimization model; S37. Model Parameter Determination: The values ​​of various parameters in the model are determined based on the actual engineering situation. The methods for parameter determination include: Field measurement verification: Select similar engineering projects to measure electric field strength and radio interference values; Design specification verification: All limits are compared with the latest national standards; Economic parameter audit: The cost engineer reviews the reasonableness of the cost parameters; Expert review and confirmation: Organize an expert review meeting to confirm the parameter values.

[0087] S38. Use Python code to implement mathematical models, write calculation programs to optimize models, and achieve automated modeling and solving; S39. Model Validation and Sensitivity Analysis: Randomly generate 1000 solutions, check the constraint satisfaction, select 10 typical schemes, compare the simplified model with the full 3D simulation results, and finally perform parameter sensitivity analysis. S310. Model Output and Application: Outputs optimization results, including the Pareto optimal solution set, the objective function values ​​and constraint satisfaction of each solution, and provides a visualization report. Specifically, the execution logic of the `generate_optimization_report` function first completes the initial configuration of optimization results, problem definition, and output path; then, it extracts the Pareto optimal solution set and the core data of the corresponding Pareto front; subsequently, it selects representative optimal solutions with engineering value based on the minimum voltage as the core optimization objective; at the same time, it verifies the accuracy of the objective function and the compliance of the constraints for all solutions; finally, it generates corresponding visual analysis charts. S4. Optimization and scheme generation based on intelligent algorithms: The optimization model established in step S3 is solved using a genetic algorithm to obtain several Pareto optimal transmission line layout schemes. For each scheme, the three-dimensional electromagnetic coupling model is used for verification calculation to ensure that it meets all constraints. S5. Protection Effect Evaluation and Scheme Recommendation: For each optimization scheme generated in step S4, evaluate its overvoltage suppression effect on the pipeline under typical working conditions, and conduct a comprehensive evaluation in combination with engineering modification costs and implementation difficulty, and output the recommended optimal layout optimization scheme and the corresponding expected induced voltage level of the pipeline.

[0088] Finally, the induced voltage in the pipeline was measured before and after the line was put into operation, and the results were compared with the simulation results to correct the model parameters.

[0089] Figure 5 An embodiment of the buried pipeline overvoltage protection system based on power transmission line layout optimization of the present invention is shown.

[0090] In this optional embodiment, the buried pipeline overvoltage protection system based on power transmission line layout optimization includes: Data acquisition and modeling module: used to input or import basic data of transmission lines, pipelines, and environment, and automatically build an initial three-dimensional electromagnetic coupling simulation model; Sensitivity Analysis Module: This module is used to automatically identify key layout parameters from line parameters, perform batch calculations by calling simulation models, complete sensitivity analysis of each parameter, and output a sensitivity ranking report. Optimization model building module: This module automatically transforms engineering problems into mathematical optimization models based on user-defined optimization objectives and various constraints. Optimization Solving Engine Module: Integrates multiple optimization algorithms to automatically solve the constructed optimization model and output multiple feasible optimization solutions and their objective function values; Scheme Evaluation and Decision Support Module: This module performs electromagnetic simulation verification on the schemes output by the optimization solution engine, and combines the cost estimation model to conduct a comprehensive technical and economic evaluation of each scheme, providing decision support in the form of charts and reports. Database and knowledge base: Used to store basic parameters, simulation results, optimization schemes, historical cases, and knowledge such as line design specifications and pipeline safety standards, providing data support for each module; The system adopts a B / S architecture. The front end uses the Vue.js framework to provide a visual operation interface, while the back end is developed using Python. It integrates the APIs of commercial simulation software such as COMSOL or ANSYS for electromagnetic calculations. The optimization algorithm is based on PyGMO or a custom implementation. The system supports multi-user collaboration and project management.

[0091] This invention is not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this invention is limited only by the appended claims.

Claims

1. A method for overvoltage protection of buried pipelines based on power transmission line layout optimization, characterized in that, include: S1. Basic Data Acquisition and 3D Scene Modeling: Collect parameters of power transmission lines, buried oil and gas pipelines, spatial relative position information of power transmission lines and buried oil and gas pipelines, and soil environmental parameters in the target area. Organize them into a dataset and construct an initial 3D electromagnetic coupling model containing power transmission lines, buried pipelines and surrounding soil environment through the dataset. S2. Identification and Sensitivity Measurement Analysis of Key Layout Parameters: From the design parameters of the transmission line, key layout parameters that significantly affect the induced voltage of the pipeline are identified. The sensitivity coefficient of each layout parameter change to the maximum induced voltage of the pipeline is calculated by using the parameter perturbation method and the three-dimensional electromagnetic coupling model. S3. Establish a multi-constraint layout optimization mathematical model: With minimizing the maximum induced voltage along the pipeline as the objective function, the key layout parameters identified in step S2 as optimization variables, and the electrical performance constraints, structural safety constraints, engineering economic constraints, and pipeline safety voltage threshold as constraints, a multi-objective layout optimization mathematical model is established. S4. Optimization and scheme generation based on intelligent algorithms: The optimization model established in step S3 is solved using a genetic algorithm to obtain several Pareto optimal transmission line layout schemes. For each scheme, the three-dimensional electromagnetic coupling model is used for verification calculation to ensure that it meets all constraints. S5. Protection Effect Evaluation and Scheme Recommendation: For each optimization scheme generated in step S4, evaluate its overvoltage suppression effect on the pipeline under typical working conditions, and conduct a comprehensive evaluation in combination with engineering modification costs and implementation difficulty, and output the recommended optimal layout optimization scheme and the corresponding expected induced voltage level of the pipeline.

2. The method for overvoltage protection of buried pipelines based on power transmission line layout optimization according to claim 1, characterized in that, The initial three-dimensional electromagnetic coupling model constructed in step S1, which includes the transmission line, buried pipeline, and surrounding soil environment, includes: Data preprocessing: unify all spatial coordinates to a coordinate system, unify them to the International System of Units (SI), remove outliers, and fill in missing values ​​using interpolation. Model selection: Professional multiphysics simulation software is used, which supports multiphysics coupling calculations of electromagnetic fields, circuits, and thermal fields; Establish geometric models: Using the collected data, model the power transmission lines, buried pipelines, soil environment, and spatial relationships respectively; Material property assignment: Assign material properties and typical values ​​to conductors, pipes, anti-corrosion coatings, soil, and air; Physics field settings: Set the excitation source, electromagnetic field module, and boundary conditions respectively; Mesh generation: Free tetrahedral mesh is used to adapt to complex geometries; Theoretical verification: The induced voltage in the pipeline under a simple scenario was calculated using the Nelson formula. The error was compared with the simulation results of the model. The error should be ≤5%. Typical sections that have been built were selected, and the induced voltage and electric field strength of the pipeline were measured. The average error was compared with the simulation results. The error should be ≤8%. If the error exceeds the tolerance, the material parameters or boundary conditions should be adjusted.

3. The method for overvoltage protection of buried pipelines based on power transmission line layout optimization according to claim 1, characterized in that, The key layout parameters in step S2 include at least: the phase sequence arrangement of the conductors, the horizontal distance of each phase conductor relative to the pipeline, the suspension height of the conductors above the ground, and the position of the tower.

4. The method for overvoltage protection of buried pipelines based on power transmission line layout optimization according to claim 1, characterized in that, The parameter perturbation method includes the following steps: S21. Determine the layout parameters to be analyzed and their range of variation: Based on industry design regulations and engineering practice experience, select layout parameters that have a significant impact on pipeline induced voltage and are adjustable in engineering. The selection criteria include: significant electromagnetic impact, engineering adjustability, economic feasibility, and safety compliance. S22, Parameter Discretization Sampling: Discretize each layout parameter within its range of variation using an equal-interval sampling method; S23. Single-parameter disturbance simulation calculation: Based on the three-dimensional electromagnetic coupling model, each layout parameter is set as its discrete sampling value in turn, while keeping other parameters as the reference value, and electromagnetic field simulation calculation is performed to extract the maximum value of induced voltage along the pipeline. S24. Calculate the sensitivity coefficient: Based on the simulation results, calculate the sensitivity coefficient of each layout parameter to the maximum induced voltage of the pipeline; S25. Sensitivity processing of discrete parameters: For discrete layout parameters, the range method is used to quantify their sensitivity. S26. Batch Automated Calculation Process: Build a computing system with a three-tier architecture of client-server-computing cluster to realize batch automated simulation and sensitivity calculation of parameters; S27. Sensitivity Ranking and Visualization: Based on the calculated sensitivity coefficients, the layout parameters are ranked and a sensitivity ranking chart, parameter-voltage response curve, Pareto front plot, and three-dimensional sensitivity distribution cloud map are generated.

5. The method for overvoltage protection of buried pipelines based on power transmission line layout optimization according to claim 4, characterized in that, The sensitivity coefficient in step S24 Defined as: ;in, : The change in the maximum induced voltage of the pipeline; Layout parameters The change in; To facilitate comparison of the effects of parameters with different dimensions, a normalized sensitivity coefficient is used: 。 6. The method for overvoltage protection of buried pipelines based on power transmission line layout optimization according to claim 1, characterized in that, The step S3 of establishing a multi-objective layout optimization mathematical model includes: S31. Establish a mathematical model for optimizing the layout of power transmission lines, transforming the engineering problem into a mathematical optimization problem; S32. Determine key variables based on sensitivity analysis: Based on the sensitivity analysis results of step S2, select layout parameters that have a significant impact on pipeline induced voltage and are adjustable in engineering as optimization variables. S33. Objective function construction: Construct a dual objective function with minimizing the maximum induced voltage in the pipeline as the primary objective and the cost of line modification as the secondary objective; S34. Constraint Construction: Construct multiple types of constraints, including electrical performance constraints, structural safety constraints, engineering economic constraints, and pipeline safety voltage thresholds. S35. Multi-objective processing strategy: Use Pareto optimization method, weighted sum method and ε-constraint method to transform multi-objective optimization problem into single-objective problem; S36. Organize into a mathematical model: Integrate the objective function and constraints into a complete mathematical optimization model; S37. Determining the parameters of the model: Determine the values ​​of various parameters in the model based on the actual engineering situation; S38. Implement mathematical models using Python code: Write a calculation program for the optimization model to achieve automated modeling and solving; S39. Model Validation and Sensitivity Analysis: Verify the accuracy of the model through random sampling and full 3D simulation comparison, and conduct parameter sensitivity analysis; S310. Model Output and Application: Output optimization results, including the Pareto optimal solution set, the objective function values ​​and constraint satisfaction of each scheme, and provide a visualization report.

7. A method for overvoltage protection of buried pipelines based on power transmission line layout optimization according to claim 6, characterized in that... The multi-objective layout optimization mathematical model established in step S3 is expressed as follows: ,in, To optimize the variable vector, its components Key layout parameters that significantly affect the induced voltage of the pipeline are identified in step S2, including but not limited to the conductor phase sequence arrangement, the horizontal distance of each phase conductor relative to the pipeline, the conductor suspension height to the ground, and the tower location. The objective function vector represents the maximum induced voltage along the pipeline, which is calculated using the three-dimensional electromagnetic coupling model. : is the economic objective function, representing the cost of line modification caused by the layout adjustment; These inequality constraints together constitute the electrical performance constraints, structural safety constraints, engineering economic constraints, and pipeline safety voltage thresholds for transmission lines. : These are the lower and upper bound vectors of the optimization variable x, respectively, which are determined by engineering design specifications, safety standards, and engineering economic requirements.

8. The method for overvoltage protection of buried pipelines based on power transmission line layout optimization according to claim 6, characterized in that, The constraints include: Electrical constraints: The power frequency electric field strength and radio interference level of the line shall not exceed the standard limits; the changes in the inductance and capacitance parameters of the line shall be within the allowable range to ensure the correct operation of the relay protection. Structural constraints: The conductor-to-ground distance, tower load, and safety distance meet the requirements of the regulations; Economic constraints: The additional costs caused by optimization, such as changes in route length, increased number of poles and towers, and use of special poles and towers, shall not exceed the budget threshold; Safety constraints: The induced voltage of the optimized pipeline must be lower than the breakdown voltage of its anti-corrosion layer or the safety limit specified in relevant standards.

9. A method for overvoltage protection of buried pipelines based on power transmission line layout optimization according to claim 1, characterized in that, The induced voltage in the pipeline was measured before and after the line was put into operation, and the results were compared with the simulation results to correct the model parameters.

10. A buried pipeline overvoltage protection system based on transmission line layout optimization, comprising the application of the buried pipeline overvoltage protection method based on transmission line layout optimization as described in claims 1-9, characterized in that, include: Data acquisition and modeling module: used to input or import basic data of transmission lines, pipelines, and environment, and automatically build an initial three-dimensional electromagnetic coupling simulation model; Sensitivity Analysis Module: This module is used to automatically identify key layout parameters from line parameters, perform batch calculations by calling simulation models, complete sensitivity analysis of each parameter, and output a sensitivity ranking report. Optimization model building module: This module automatically transforms engineering problems into mathematical optimization models based on user-defined optimization objectives and various constraints. Optimization Solving Engine Module: Integrates multiple optimization algorithms to automatically solve the constructed optimization model and output multiple feasible optimization solutions and their objective function values; Scheme Evaluation and Decision Support Module: This module performs electromagnetic simulation verification on the schemes output by the optimization solution engine, and combines the cost estimation model to conduct a comprehensive technical and economic evaluation of each scheme, providing decision support in the form of charts and reports. Database and knowledge base: Used to store basic parameters, simulation results, optimization schemes, historical cases, and knowledge such as line design specifications and pipeline safety standards, providing data support for each module; The system adopts a B / S architecture. The front end uses the Vue.js framework to provide a visual operation interface, while the back end is developed using Python. It integrates the APIs of commercial simulation software such as COMSOL or ANSYS for electromagnetic calculations. The optimization algorithm is based on PyGMO or a custom implementation. The system supports multi-user collaboration and project management.

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