A method for identifying and preventing corrosion hot spots in pipelines affected by high-speed rail

Abstract

The present invention provides a method for identifying and preventing corrosion hotspots in pipelines affected by high-speed railways. In view of the unclear key parameters of dynamic AC interference corrosion risk, the high-frequency peak AC current density is determined as the key parameter of corrosion risk, and the data analysis method of high-speed railway interference parameters is clarified; in view of the lack of equivalent processing methods for numerical simulation calculations, based on electrical calculations and corrosion theory, and by mutual correction of numerical simulation calculation results with field data, an equivalent processing flow for the pipeline end and anti-corrosion layer is determined; in view of the difficulty in determining the installation position of the drainage bed interfered by the high-speed railway, an interference law analysis is performed based on field monitoring data, and a drainage bed selection method is refined; in view of the unsystematic and imperfect drainage system of the high-speed railway interference, a full-process high-speed railway interference corrosion risk solution from data monitoring, interference analysis, prevention and control optimization, to effect evaluation is constructed based on interference laws, interference characteristics and corrosion laws.

Description

Technical Field

[0001] The present invention relates to the field of computer technology, and in particular to a method for identifying and preventing pipeline corrosion hotspots affected by high-speed railways. Background Art

[0002] With the rapid development of the energy and transportation industries, there are more and more cases where gas pipelines are parallel or intersecting with high-speed rail lines, and buried pipelines are increasingly seriously disturbed by stray currents. Taking Beijing as an example, by the end of 2022, Beijing Gas had more than 17,000 kilometers of buried steel pipelines in service. In addition, Beijing is the largest railway hub in the country, with many railway trunk lines such as the Beijing-Guangzhou Line, Beijing-Shanghai Line, Beijing-Kowloon Line, Beijing-Baotou Line, and Beijing-Tong Line radiating to all parts of the country. The huge rail transit and power network and gas pipeline network are densely distributed in the Beijing area, and the risk of stray current interference is becoming more and more serious.

[0003] Due to the limitations of space resources and geographical environment, high-speed railways and buried steel pipelines are often built in parallel or across long distances in "public corridors", which makes the stray current interference problem faced by the pipelines very serious. Many cases of perforation and leakage caused by stray current corrosion on electrified railways have been reported at home and abroad, making the corrosion problem caused by AC electrified railways a focus of attention.

[0004] For city gas, there are three common types of stray current interference, namely steady-state AC interference caused by high-voltage AC transmission lines, dynamic DC interference caused by subway rail transit, and dynamic AC interference caused by high-speed rail. With the construction and commissioning of more and more electrified railways and pipelines, the interference problem of electrified railways on pipelines is becoming increasingly serious. However, the corrosion behavior of pipelines under dynamic AC interference is still unknown. Is the corrosion behavior under dynamic AC interference similar to that under steady-state AC interference, or is there a difference? How to accurately assess the corrosion risk under dynamic AC interference has become an urgent need for actual production. Therefore, the study of the corrosion behavior of buried metal pipelines under dynamic AC interference of electrified railways, especially the identification of interference hotspots and drainage locations, drainage optimization design and implementation, and the safe operation of pipelines near high-speed railways in actual projects, has important reference and guiding significance.

[0005] The stray current interference faced by the above three types of city gas is different in interference characteristics, corrosion laws, drainage prevention and control, evaluation indicators, digital model calculation, etc. The main differences are as follows:

[0006] First, unlike the steady-state AC interference caused by high-voltage AC transmission lines on buried pipelines, high-speed railways produce pulsed dynamic AC interference on nearby pipelines. The AC and DC parameters on the pipelines are in a dynamic fluctuation state, and their interference characteristics are closely related to the locomotive traction power supply mode, locomotive operating status, etc.; due to the frequent fluctuations in the interference parameters of high-speed railways, data analysis, corrosion laws and evaluation are different from the interference caused by high-voltage AC transmission lines.

[0007] Second, the dynamic DC interference caused by subway rail transit to buried pipelines is different from that caused by high-speed rail, which mainly produces AC interference, thus affecting the cathodic protection potential of the pipelines; the interference form is mainly inductive coupling, so the drainage position is different from the subway interference, and the drainage bed is not at the intersection of the pipeline and rail transit or relatively close to it; in addition, due to the differences in the DC and AC interference signals generated, the drainage methods are different. Summary of the invention

[0008] The present invention aims to provide a method for identifying and preventing corrosion hot spots in pipelines affected by high-speed railways, which overcomes the above problems or at least partially solves the above problems.

[0009] To achieve the above object, the technical solution of the present invention is specifically implemented as follows:

[0010] The present invention provides a method for identifying and preventing corrosion hot spots in pipelines affected by high-speed railways, comprising:

[0011] Get basic information;

[0012] Calculate the terminal equivalent impedance and the corrected surface resistivity of the anti-corrosion layer according to the basic information;

[0013] Determine the best interference drainage location;

[0014] Obtain data to be analyzed and determine prevention and control indicators;

[0015] Determine drainage design plan.

[0016] The basic information includes:

[0017] Basic information of pipelines, including at least: pipeline material, pipe resistivity, pipe relative magnetic permeability, pipeline outer diameter, pipeline wall thickness, anti-corrosion layer resistivity, soil resistivity, and pipeline direction;

[0018] High-speed rail basic information: at least including: power supply mode, traction network and positive feeder distribution, traction substation power supply type, traction network longitudinal resistance, positive feeder longitudinal resistance, rail longitudinal resistance, railway leakage resistance, high-speed rail direction;

[0019] The power-off potential along the pipeline is obtained by a power-off potential testing method, wherein the power-off potential testing method includes: based on a test piece method, using a cathodic protection test pile to detect the power-off potential along the pipeline.

[0020] The step of calculating the terminal equivalent impedance according to the basic information includes:

[0021] The longitudinal impedance r of the pipeline per kilometer is calculated using formula (1):

[0022]

[0023] Where ρ is the metal resistivity; L is the length of the pipeline; R out is the outer radius of the pipe; R in is the inner radius of the pipe;

[0024] The leakage conductance per kilometer of pipeline is calculated using formula (2):

[0025]

[0026] Where R is the resistivity of the anti-corrosion layer;

[0027] The pipeline attenuation coefficient α is calculated using formula (3):

[0028]

[0029] The characteristic impedance of the pipeline is calculated using formula (4):

[0030]

[0031] Where r is the longitudinal impedance of the pipeline per km, Ω; g is the leakage conductance of the pipeline per km, S;

[0032] Use formula (5) to calculate the equivalent impedance:

[0033] Z r =R G coth(αx)(5)

[0034] Among them, Z r is the equivalent impedance, Ω; R G is the characteristic impedance, Ω; α is the attenuation coefficient; x is the length of the equivalent pipeline, km.

[0035] Wherein, calculating the corrected surface resistivity of the anti-corrosion layer according to the basic information includes:

[0036] Use formula (6) to calculate the fault grounding resistance:

[0037]

[0038] Among them, R defect is the defect resistance, Ω; d is the defect diameter, m; ρ soil is soil resistivity, Ω·m;

[0039] The relationship between the actual resistance of the anti-corrosion layer and the actual surface resistance between two adjacent defects is calculated using formula (7):

[0040]

[0041] Among them, R coating is the actual resistance of the anti-corrosion layer, Ω; r coating is the actual surface resistivity of the anti-corrosion layer, Ω·m; D is the outer diameter of the pipeline, mm; L0 is the defect spacing, m;

[0042] The relationship between the corrected resistance of the anti-corrosion layer and the defect resistance is calculated using formula (8):

[0043]

[0044] Among them, R equivalent Corrected resistance of the anti-corrosion layer, Ω; R coating is the actual resistance of the anti-corrosion layer, Ω; R defect is the defect resistance, Ω;

[0045] The corrected surface resistivity of the anti-corrosion layer is calculated using formula (9):

[0046]

[0047] Among them, r equivalent Corrected surface resistivity of the anti-corrosion layer, Ω·m 2 ; r coating is the actual surface resistivity of the anti-corrosion layer, Ω·m 2 ; D is the outer diameter of the pipe, mm; L0 is the defect spacing, m; ρ soil is the soil resistivity, Ω·m, and d is the defect diameter, m.

[0048] Wherein, determining the optimal interference drainage position includes:

[0049] Simultaneously monitoring the AC interference voltage along the interfered pipeline and making a first graph, wherein the abscissa of the first graph is the pipeline mileage and the ordinate of the graph is the AC interference voltage;

[0050] Filter the maximum point in the first graph, and determine that the closest point of the maximum point to the high-speed railway is the traction substation and AT station of the high-speed railway;

[0051] The traction substation, the AT station and the midpoint between the two are determined as the optimal interference drainage position, and the optimal interference drainage position is the drainage bed installation position.

[0052] Wherein, determining the optimal interference drainage position includes:

[0053] On-site survey to determine the location of the high-speed rail traction substation and AT station;

[0054] Mark the closest point to the traction substation and the AT station on the pipeline;

[0055] The marked point and the midpoint of the marked point are determined as the optimal interference drainage position, and the optimal interference drainage position is the drainage bed installation position.

[0056] Wherein, obtaining the data to be analyzed and determining the prevention and control indicators include:

[0057] Install remote transmission devices or data monitoring recorders to obtain data to be analyzed;

[0058] Draw a second graph, count all peak values ​​according to the second graph, the abscissa of the second graph is time, and the ordinate of the second graph is the AC interference parameter;

[0059] Set fixed interval value;

[0060] Filter all peaks with the largest number of peaks or the largest proportion in the fixed interval;

[0061] The average value of all peak values ​​is calculated and determined as a prevention and control index, where the prevention and control index is a high-frequency peak AC interference parameter.

[0062] Wherein, determining the drainage design scheme includes:

[0063] Establishing a calculation model according to the basic information, and correcting the calculation model;

[0064] Determining an optimal drainage position according to the optimal interference drainage position;

[0065] Identify mitigation options.

[0066] The method also includes: on-site application and effect evaluation.

[0067] Wherein, the on-site application and effect evaluation include:

[0068] Statistics of high-frequency peak AC interference parameters, output drainage effect evaluation and prevention and control compliance evaluation.

[0069] It can be seen that through the pipeline corrosion hotspot identification technology and prevention and control method provided by the present invention, in view of the unclear key parameters of dynamic AC interference corrosion risk, the correlation between various interference parameters and corrosion risk is established through a large amount of field data and simulation experimental data, and finally the high-frequency peak AC current density is determined as the key parameter of corrosion risk, and the data analysis method of high-speed rail interference parameters is clarified; in view of the lack of equivalent processing methods for numerical simulation calculations, based on electrical calculations and corrosion theory, and by mutual correction of numerical simulation calculation results with field data, the equivalent processing flow of the pipeline end and the anti-corrosion layer is determined; in view of the difficulty in determining the installation position of the high-speed rail interference drainage bed, the interference law analysis is carried out based on the field monitoring data, and the drainage bed selection method is refined; in view of the problem that the high-speed rail interference drainage system is not systematic and imperfect, a full-process high-speed rail interference corrosion risk solution from data monitoring, interference analysis, prevention and control optimization, and effect evaluation is constructed based on interference laws, interference characteristics and corrosion laws. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0071] Figure 1 A flow chart of a method for identifying and preventing corrosion hot spots in pipelines affected by high-speed railways provided in an embodiment of the present invention;

[0072] Figure 2 A flow chart of a method for determining an optimal interference drainage position provided by an embodiment of the present invention;

[0073] Figure 3 A flow chart of another method for determining an optimal interference drainage position provided by an embodiment of the present invention;

[0074] Figure 4 A flowchart of obtaining data to be analyzed and determining prevention and control indicators provided by an embodiment of the present invention;

[0075] Figure 5 A schematic diagram of AC interference parameters provided by an embodiment of the present invention;

[0076] Figure 6 A wiring diagram provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0077] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0078] The core of the present invention is:

[0079] The data analysis method of high-speed rail interference parameters was clarified, and the key parameters of corrosion risk were proposed, namely, the high-frequency peak AC interference parameters have the greatest correlation with interference risk. This improved the accuracy of corrosion law analysis and risk assessment, and provided a key basis for drainage location screening and the establishment of prevention and control technical indicators.

[0080] The terminal equivalent and anti-corrosion layer equivalent methods involved in digital-analog calculations were proposed, which provided a simplified solution for carrying out digital-analog calculations and improved the matching of the combination of digital-analog calculations and field measured data.

[0081] The basis for selecting high-speed rail interference hotspots was obtained, which can guide enterprises to quickly and accurately determine the installation location of the drainage bed, form an optimized design of the drainage plan, improve work efficiency and achieve precise prevention and control.

[0082] A complete system for identifying and preventing dynamic AC interference hotspots of high-speed railways is summarized, which involves a standardized process of basic information investigation, model equivalent processing, determination of interference drainage locations, data collection and establishment of prevention and control indicators, determination and optimization of drainage design schemes, on-site application and effect evaluation. This can better solve the problem of corrosion risk of urban gas pipelines affected by high-speed railways.

[0083] Figure 1 A flowchart of a method for identifying and preventing corrosion hot spots in pipelines affected by high-speed rail provided in an embodiment of the present invention is shown. Figure 1 The embodiment of the present invention provides a method for identifying and preventing pipeline corrosion hot spots affected by high-speed rail, including:

[0084] S1, obtain basic information.

[0085] Specifically, the present invention first investigates basic information, including:

[0086] Basic information includes:

[0087] Basic information of pipelines, including at least: pipeline material, pipe resistivity, pipe relative magnetic permeability, pipeline outer diameter, pipeline wall thickness, anti-corrosion layer resistivity, soil resistivity, and pipeline direction;

[0088] High-speed rail basic information: at least including: power supply mode, traction network and positive feeder distribution, traction substation power supply type, traction network longitudinal resistance, positive feeder longitudinal resistance, rail longitudinal resistance, railway leakage resistance, high-speed rail direction;

[0089] The power-off potential along the pipeline is obtained by a power-off potential testing method, wherein the power-off potential testing method includes: based on the test piece method, using the cathodic protection test pile to detect the power-off potential along the pipeline.

[0090] S2, calculate the terminal equivalent impedance and the corrected surface resistivity of the anti-corrosion layer based on the basic information.

[0091] Specifically, this step is a model equivalent processing step, which mainly includes terminal equivalent and anti-corrosion layer equivalent. Terminal equivalent means that when performing simulation calculations, the focus is on the pipelines close to the transmission line section. For pipelines at a large distance from the transmission line, equivalent processing can be performed to meet the electrical calculation requirements; the anti-corrosion layer equivalent is to eliminate the influence of coating defects on the resistivity of the anti-corrosion layer surface. Usually, the anti-corrosion layer correction resistance and defect resistance are defaulted to a parallel structure, so that the anti-corrosion layer correction surface resistivity is calculated through electrical formulas.

[0092] As an optional implementation of the embodiment of the present invention, calculating the terminal equivalent impedance according to the basic information includes:

[0093] The longitudinal impedance r of the pipeline per kilometer is calculated using formula (1):

[0094]

[0095] Where ρ is the metal resistivity; L is the length of the pipeline; R out is the outer radius of the pipe; R in is the inner radius of the pipe;

[0096] The leakage conductance per kilometer of pipeline is calculated using formula (2):

[0097]

[0098] Where R is the resistivity of the anti-corrosion layer;

[0099] The pipeline attenuation coefficient α is calculated using formula (3):

[0100]

[0101] The characteristic impedance of the pipeline is calculated using formula (4):

[0102]

[0103] Where r is the longitudinal impedance of the pipeline per km, Ω; g is the leakage conductance of the pipeline per km, S;

[0104] Use formula (5) to calculate the equivalent impedance:

[0105] Z r =R G coth(αx)(5)

[0106] Among them, Z r is the equivalent impedance, Ω; R G is the characteristic impedance, Ω; α is the attenuation coefficient; x is the length of the equivalent pipeline, km.

[0107] As an optional implementation of the embodiment of the present invention, calculating the corrected surface resistivity of the anti-corrosion layer according to the basic information includes:

[0108] Use formula (6) to calculate the fault grounding resistance:

[0109]

[0110] Among them, R defect is the defect resistance, Ω; d is the defect diameter, m; ρ soil is soil resistivity, Ω·m;

[0111] The relationship between the actual resistance of the anti-corrosion layer and the actual surface resistance between two adjacent defects is calculated using formula (7):

[0112]

[0113] Among them, R coating is the actual resistance of the anti-corrosion layer, Ω; r coating is the actual surface resistivity of the anti-corrosion layer, Ω·m; D is the outer diameter of the pipeline, mm; L0 is the defect spacing, m;

[0114] The relationship between the corrected resistance of the anti-corrosion layer and the defect resistance is calculated using formula (8):

[0115]

[0116] Among them, R equivalent Corrected resistance of the anti-corrosion layer, Ω; R coating is the actual resistance of the anti-corrosion layer, Ω; R defect is the defect resistance, Ω;

[0117] The corrected surface resistivity of the anti-corrosion layer is calculated using formula (9):

[0118]

[0119] Among them, r equivalent Corrected surface resistivity of the anti-corrosion layer, Ω·m 2 ; r coatingis the actual surface resistivity of the anti-corrosion layer, Ω·m 2 ; D is the outer diameter of the pipe, mm; L0 is the defect spacing, m; ρ soil is the soil resistivity, Ω·m, and d is the defect diameter, m.

[0120] S3, determine the best interference drainage position.

[0121] Specifically, in order to explore the interference law of high-speed rail on buried pipelines, numerical simulation was performed using CDEGS software to determine the correlation between pipeline interference value and high-speed rail. Through numerical simulation calculation and analysis, the following two important laws were obtained:

[0122] First, the distribution law of the maximum interference value along the pipeline at the same time section was obtained, and the interference peaks were determined to be the traction substation, AT station, locomotive location, and the start and end positions of the parallel section;

[0123] Secondly, the location of the maximum interference value along the pipeline within a certain operating cycle was obtained, and the maximum interference value was determined to be the traction substation, AT station and the midpoint between the two. This location is the optimal drainage location for installing the drainage bed.

[0124] Therefore, when determining the best interference drainage position, the interference rules summarized above can be used to complete the selection of the best interference drainage position. There are two selection methods:

[0125] See also Figure 2 As an optional implementation of an embodiment of the present invention, determining the best interference drainage position includes: synchronously monitoring the AC interference voltage along the interfered pipeline and making a first graph, the horizontal axis of the first graph is the pipeline mileage, and the vertical axis of the graph is the AC interference voltage; screening the maximum point in the first graph, and determining that the maximum point is closest to the high-speed rail as the traction substation and AT station of the high-speed rail; determining the traction substation and AT station and the midpoint between the two as the best interference drainage position, and the best interference drainage position is the drainage bed installation position. Specifically, when it is impossible to conduct on-site investigation and survey to obtain the specific location of the traction substation and AT station along the high-speed rail, it is necessary to conduct a short-term synchronous monitoring along the pipeline, and by analyzing the interference maximum value under the section at the same time, infer the traction substation and AT station, so as to determine the interference maximum value and the midpoint of the extreme value as the best interference drainage position.

[0126] See also Figure 3As an optional implementation of an embodiment of the present invention, determining the best interference drainage position includes: determining the location of the traction substation and AT station of the high-speed railway through on-site investigation; marking the closest point to the traction substation and AT station on the pipeline; determining the marked point and the midpoint of the marked point as the best interference drainage position, and the best interference drainage position is the installation position of the drainage bed. Specifically, through on-site investigation and investigation of the specific locations of the traction substation and AT station along the high-speed railway, the closest point to the traction substation and AT station is then marked on the pipeline, and the closest point and the midpoint between the two are the best interference drainage positions.

[0127] S4, obtain the data to be analyzed and determine the prevention and control indicators.

[0128] Specifically, see Figure 4 , obtain the data to be analyzed, and determine the prevention and control indicators, including: installing a remote transmission device or a data monitoring recorder to obtain the data to be analyzed; making a second graph, counting all peak values ​​according to the second graph, the horizontal axis of the second graph is time, and the vertical axis of the second graph is the AC interference parameter; setting a fixed interval value; screening all peak values ​​with the largest number of peaks or the largest proportion in the fixed interval; calculating the average value of all peak values ​​to determine as the prevention and control indicator, and the prevention and control indicator is the high-frequency peak AC interference parameter.

[0129] Among them, the real-time transmission of parameters is realized by installing remote transmission, and the parameters include on-off potential, AC current density, and AC interference voltage. The remote transmission device avoids the problems of poor timeliness and large errors in manual detection. The data collected by the remote transmission device has two key uses: one is to complete the interference risk assessment and the step-by-step design of the optimal drainage plan through remote transmission data collection; the other is to complete the effect evaluation after the interference drainage application.

[0130] The cathodic protection remote transmission device is installed at the best interference drainage position to collect the cathodic protection on-off potential, AC interference voltage and AC current density in real time. The collection frequency is 1s / time, and the monitoring is carried out for at least 24 hours. The fixed interval value is generally set to 30A / m 2 .

[0131] When analyzing data and determining prevention and control indicators, the AC interference parameters on pipelines near high-speed railways show pulse fluctuation characteristics. The interference parameters rise rapidly in a short period of time and fall rapidly after a period of time. The entire monitoring period is composed of multiple AC interference pulse peaks. In order to obtain the most critical parameters of high-speed railway interference risk, the high peak AC interference parameters and high frequency peak AC interference parameters are counted respectively. Figure 5 ,The results show that the high-frequency peak AC interference parameters are most ,correlated with the interference risk.

[0132] The high frequency in the high frequency peak AC interference parameter is defined as the ratio of the number of peaks in a fixed interval to the number of peaks in the entire interval is relatively large, and then the average value of the peaks in the fixed interval is the high frequency peak AC interference parameter.

[0133] According to the above analysis, the formulation of prevention and control indicators (AC interference voltage and current density) and the evaluation of drainage effect are also based on high-frequency peak AC interference parameters.

[0134] S5, determine the drainage design plan.

[0135] Specifically, determining the drainage design plan includes: establishing a calculation model based on basic information and correcting the calculation model; determining the best drainage position based on the best interference drainage position; and determining a mitigation plan.

[0136] The calculation model is established based on the basic information and the calculation model is corrected. The specific implementation is divided into two steps:

[0137] The first step is to establish a calculation model based on the basic information, position relationship, terminal equivalence, anti-corrosion layer equivalence, etc. of the pipeline and high-speed rail, and calculate the AC interference parameters along the pipeline according to the geometric model;

[0138] Specific calculation method: The engineering theory and physical model used in numerical simulation technology are fundamentally based on Maxwell's equations in the form of integration or calculus. At present, there are many methods for solving Maxwell's equations. The numerical simulation software used in this project is based on the method of moments for solution. This calculation uses professional numerical simulation software (CDEGS) for computer simulation, which is based on the method of moments for calculation and solution. This method is to transform a continuous equation into a discrete algebraic equation set through two processes of discretization and verification, and then obtain the target electric field or magnetic field distribution by solving the discrete matrix equation, so as to obtain the corresponding voltage and current values ​​through numerical calculation of the electric field.

[0139] The second step is to verify the accuracy of the calculation model. The field test results are compared with the calculation results. If the relative error between the two exceeds ±10%, the parameters of the terminal equivalent and the anti-corrosion layer equivalent are adjusted until the relative error between the two is within ±10%.

[0140] When determining the optimal drainage position, the above two methods are used to determine the optimal interference drainage position; then the drainage position is surveyed, and the drainage bed forms at different locations are preliminarily determined according to the surrounding environment and space, including deep well bed, distributed bed, strip bed, etc.

[0141] When determining the specific implementation of the mitigation plan, after determining the location and form of the drainage bed, the drainage bed specifications (such as zinc belt length, number of anodes, etc.) are gradually increased, and the CDEGS numerical simulation software is used to obtain the interference parameter values ​​in each case; when the interference parameter values ​​along the pipeline are within the prevention and control indicators, the drainage mitigation plan is optimal and can be used as a basis for on-site construction.

[0142] As an optional implementation of the embodiment of the present invention, the pipeline corrosion hotspot identification technology and prevention and control method provided by the embodiment of the present invention affected by high-speed rail also include:

[0143] S6, on-site application and effect evaluation.

[0144] Specifically, on-site application and effect evaluation include: statistical high-frequency peak AC interference parameters, output drainage effect evaluation and prevention and control compliance evaluation.

[0145] In the specific implementation, the on-site construction is completed based on the drainage design plan. During the construction, the position of the drainage bed needs to be fine-tuned according to the actual situation on site to avoid the drainage bed being in the rock area and to maintain a certain construction safety distance from the buried pipeline or underground grounding material.

[0146] in accordance with Figure 6 The wiring is done as shown in the schematic diagram to complete the drainage effect evaluation. The AC interference drainage flow is monitored by uDL1, and the AC interference voltage and AC current density are monitored by uDL2. The high-frequency peak AC interference parameters are calculated according to the above data analysis method.

[0147] The first step is to evaluate the drainage effect, and analyze the parameters before and after the implementation of the drainage plan. When collecting data, the measurement points, monitoring time periods, reading time intervals, measurement methods and instrument equipment should be unified.

[0148] The second step is to evaluate the compliance of prevention and control. The interference parameters of the test piles near the drainage point are measured, and it is analyzed whether they are within the prevention and control index range. During data collection, the high-frequency peak parameters should be monitored and extracted for at least 24 hours.

[0149] It can be seen that the pipeline corrosion hotspot identification and prevention and control method affected by high-speed rail provided by the embodiment of the present invention, in response to the problem of unclear key parameters of dynamic AC interference corrosion risk, the correlation between various interference parameters and corrosion risk is established through a large amount of field data and simulation experimental data, and finally the high-frequency peak AC current density is determined as the key parameter of corrosion risk, and the data analysis method of high-speed rail interference parameters is clarified; in response to the problem of missing equivalent processing methods for numerical simulation calculations, based on electrical calculations and corrosion theory, and by mutual correction of numerical simulation calculation results with field data, the equivalent processing flow of the pipeline end and the anti-corrosion layer is determined; in response to the problem of difficulty in determining the installation position of the high-speed rail interference drainage bed, the interference law analysis is carried out based on the field monitoring data, and the drainage bed selection method is refined; in response to the problem that the high-speed rail interference drainage system is unsystematic and imperfect, a full-process high-speed rail interference corrosion risk solution from data monitoring, interference analysis, prevention and control optimization, and effect evaluation is constructed based on interference laws, interference characteristics and corrosion laws.

[0150] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for identifying and preventing corrosion hot spots in pipelines affected by high-speed railways, characterized in that: include: Get basic information; Calculate the terminal equivalent impedance and the corrected surface resistivity of the anti-corrosion layer according to the basic information; Determine the best interference drainage location; Obtain data to be analyzed and determine prevention and control indicators; Determine drainage design plan; in: Calculating the terminal equivalent impedance according to the basic information includes: The longitudinal impedance r of the pipeline per kilometer is calculated using formula (1): Where ρ is the metal resistivity; L is the length of the pipeline; R out is the outer radius of the pipe; R in is the inner radius of the pipe; Ac is the cross-sectional area of ​​the pipe; The leakage conductance per kilometer of pipeline is calculated using formula (2): Among them, R is the resistivity of the anti-corrosion layer, and A is the surface area of ​​the pipeline; The pipeline attenuation coefficient α is calculated using formula (3): The characteristic impedance of the pipeline is calculated using formula (4): Where r is the longitudinal impedance of the pipeline per km, Ω; g is the leakage conductance of the pipeline per km, S; Use formula (5) to calculate the equivalent impedance: Z r =R G coth(αx)(5) Among them, Z r is the equivalent impedance, Ω; R G is the characteristic impedance, Ω; α is the attenuation coefficient; x is the length of the equivalent pipeline, km; Calculating the corrected surface resistivity of the anti-corrosion layer according to the basic information includes: Use formula (6) to calculate the fault grounding resistance: Among them, R defect is the defect resistance, Ω; d is the defect diameter, m; ρ soil is soil resistivity, Ω·m; The relationship between the actual resistance of the anti-corrosion layer and the actual surface resistance between two adjacent defects is calculated using formula (7): Among them, R coating is the actual resistance of the anti-corrosion layer, Ω; r coating is the actual surface resistivity of the anti-corrosion layer, Ω·m; D is the outer diameter of the pipeline, mm; L0 is the defect spacing, m; The relationship between the corrected resistance of the anti-corrosion layer and the defect resistance is calculated using formula (8): Among them, R equivalent Corrected resistance of the anti-corrosion layer, Ω; R coating is the actual resistance of the anti-corrosion layer, Ω; R defect is the defect resistance, Ω; The corrected surface resistivity of the anti-corrosion layer is calculated using formula (9): Among them, r equivalent Corrected surface resistivity of the anti-corrosion layer, Ω·m 2 ; r coating is the actual surface resistivity of the anti-corrosion layer, Ω·m 2 ; D is the outer diameter of the pipe, mm; L0 is the defect spacing, m; ρ soil is soil resistivity, Ω·m, d is defect diameter, m; The obtaining of data to be analyzed and determining the prevention and control indicators include: Install remote transmission devices or data monitoring recorders to obtain data to be analyzed; Draw a second graph, count all peak values ​​according to the second graph, the abscissa of the second graph is time, and the ordinate of the second graph is the AC interference parameter; Set fixed interval value; Filter all peaks with the largest number of peaks or the largest proportion in the fixed interval; Calculate the average value of all peak values ​​and determine it as a prevention and control index, wherein the prevention and control index is a high-frequency peak AC interference parameter; Determining the drainage design scheme includes: Establishing a calculation model according to the basic information, and correcting the calculation model; Determining an optimal drainage position according to the optimal interference drainage position; Identify mitigation options; The establishing of a calculation model according to the basic information and correcting the calculation model comprises: A calculation model is established based on the basic information, position relationship, terminal equivalence, and anti-corrosion layer equivalence of the pipeline and high-speed rail, and the AC interference parameters along the pipeline are calculated based on the geometric model; To verify the accuracy of the calculation model, compare the field test results with the calculation results. If the relative error between the two exceeds ±10%, adjust the parameters of the terminal equivalent and anti-corrosion layer equivalent until the relative error between the two is within ±10%.

2. The method according to claim 1, characterized in that The basic information includes: Basic information of pipelines, including at least: pipeline material, pipe resistivity, pipe relative magnetic permeability, pipeline outer diameter, pipeline wall thickness, anti-corrosion layer resistivity, soil resistivity, and pipeline direction; High-speed rail basic information: at least including: power supply mode, traction network and positive feeder distribution, traction substation power supply type, traction network longitudinal resistance, positive feeder longitudinal resistance, rail longitudinal resistance, railway leakage resistance, high-speed rail direction; The power-off potential along the pipeline is obtained by a power-off potential testing method, wherein the power-off potential testing method includes: based on a test piece method, using a cathodic protection test pile to detect the power-off potential along the pipeline.

3. The method according to claim 1, characterized in that Determining the optimal interference drainage position includes: Simultaneously monitoring the AC interference voltage along the interfered pipeline and making a first graph, wherein the abscissa of the first graph is the pipeline mileage and the ordinate of the graph is the AC interference voltage; Filter the maximum point in the first graph, and determine that the closest point of the maximum point to the high-speed railway is the traction substation and AT station of the high-speed railway; The traction substation, the AT station and the midpoint between the two are determined as the optimal interference drainage position, and the optimal interference drainage position is the drainage bed installation position.

4. The method according to claim 1, characterized in that: Determining the optimal interference drainage position includes: On-site survey to determine the location of the high-speed rail traction substation and AT station; Mark the closest point to the traction substation and the AT station on the pipeline; The marked point and the midpoint of the marked point are determined as the optimal interference drainage position, and the optimal interference drainage position is the drainage bed installation position.

5. The method according to claim 1, characterized in that Also includes: On-site application and effect evaluation.

6. The method according to claim 5, characterized in that The field application and effect evaluation include: Statistics of high-frequency peak AC interference parameters, output drainage effect evaluation and prevention and control compliance evaluation.

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