A calculation method and system for the influence of stray current in urban rail transit on the cross-potential of pipelines

Abstract

The present invention discloses a calculation method and system for the influence of stray current in urban rail transit on the cross potential of pipelines. The method includes the following steps: S1: Place the spatial position of the target pipeline and the spatial position of the urban rail transit line in a three-dimensional space at the same time, and obtain the coordinate data of both to acquire the position information between them; S2: Then perform two-dimensional processing, and match the various parameters measured on the actual track of the urban rail transit line to the corresponding positions on the track in the two-dimensional image; S3: Construct an SSIM-V single-factor evaluation model for the influence of stray current on the ground potential. According to the principle of averaging, further obtain its potential information based on the fact that the leakage current is evenly distributed at each fastener of the rail within a fixed range d to generate stray current; S4: Estimate the total influence range of the potential of each fastener of the rail on the pipeline. The advantages of the present invention are: it is possible to view the size of the area affected by stray current in different sections, and reasonably plan the insulation protection distance before insulation protection treatment.

Description

Technical Field

[0001] The present invention relates to the field of rail transit, and specifically to a calculation method and system for the influence of stray current of urban rail on the cross - ground potential of pipelines. Background Art

[0002] Existing research on the influence of stray current is based on complex numerical simulation techniques to simulate the ground structure and line conditions, which is not convenient for simply estimating the insulation protection distance in the case of the intersection of the line and the pipeline. This also makes it difficult to conduct qualitative evaluation at the initial stage of project line selection, and increases the difficulty of subsequent stray current protection. This is also reflected in some current pipeline accidents such as perforation caused by the influence of urban rail transit. The occurrence of the above problems also increases the cost of subsequent stray current treatment.

[0003] For example, a method for protecting buried pipelines from subway stray current disclosed in the patent document with the publication number CN110752880A mainly lies in: based on the established dynamic characteristic model of stray current in subway buried metal pipelines, constructing a fitness function by using the set pipeline surface potential constraint conditions, and using an optimization algorithm to determine the optimal installation position of the potentiostat. Actually, it is to solve the point with the greatest influence on the potential, and it is to select the installation position of the potentiostat; a method for predicting pipeline corrosion under subway stray current based on partial least squares method disclosed in the patent document with the publication number CN 112989660A mainly lies in: densely selecting sensors at the locations where the leakage current is the largest in the acceleration and deceleration stages, and sparsely selecting sensors at the locations where the leakage current is smaller in the uniform speed stage;

[0004] The above methods lack the operation of the influence of urban rail stray current on the cross - ground potential of pipelines, and cannot obtain the insulation protection distance that should be provided for the pipeline in the case of the intersection of the track line and the pipeline on the horizontal plane; aiming at the above problems, the present invention proposes a calculation method for the influence of urban rail stray current on the cross - ground potential of pipelines. The present invention realizes rapid qualitative determination of the total influence range of stray current on the pipeline by establishing an analytical function, so as to further determine the length design of the insulation of the return rail near important pipelines. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art; for this purpose, the present invention proposes a calculation method and system for the influence of urban rail stray current on the cross - ground potential of pipelines, which is used to solve the technical problem that the prior art cannot obtain the insulation protection distance that should be provided for the pipeline in the case of the intersection of the track line and the pipeline on the horizontal plane.

[0006] To achieve the above object, the present invention provides a calculation method for the influence of urban rail stray current on the cross - ground potential of pipelines, including the following steps:

[0007] S1: Place the spatial position of the target pipeline and the spatial position of the urban rail transit line in a three-dimensional space at the same time, and obtain the coordinate data of both to obtain the position information between them.

[0008] S2: Then, discard the vertical height of the spatial position of the target pipeline and the spatial position of the urban rail transit line, perform a flat two-dimensional processing, and place the two in the same plane; then match the various parameters measured in the actual track of the urban rail transit line to the corresponding positions on the track in the two-dimensional image. The parameters specifically include: soil resistivity, the installation position and quantity of rail fasteners, the local insulation length and insulation level of the line.

[0009] S3: Construct an SSIM-V stray current single-factor ground potential influence evaluation model. According to the principle of averaging, further obtain its potential information based on the fact that the leakage current is evenly distributed at each rail fastener within a fixed range d to generate stray current.

[0010] S4: Estimate the total influence range of the potential of each rail fastener on the pipeline.

[0011] Furthermore: The specific principle of S1 is as follows:

[0012] Perform a spatial conversion of geographical coordinates and three-dimensional coordinates on the design drawings of the urban rail transit line and the pipeline simultaneously using coordinate transformation to obtain the relative distance between them.

[0013] Furthermore: The principle of S2 is as follows:

[0014] Continue to perform flat two-dimensional processing on the spatial position of the target pipeline and the spatial position of the urban rail transit line already in the three-dimensional space using coordinate transformation to obtain the included angle line information; then match the measured rail-to-ground transition resistance of the operating line, that is, the rail insulation level and the insulation level expected to be achieved in the preliminary design stage, the local insulation length and insulation level of the line in the model, the soil resistivity along the line between the target track and the target pipeline measured by geological exploration data, and the physical information of the fasteners on the target track rail; all are matched to the two-dimensional plan for easy operation and call.

[0015] Furthermore: In S3, the SSIM-V stray current single-factor ground potential influence evaluation model is as follows:

[0016] V(x, y, θ) = Vs(x, y, θ) + Vo(x, y, θ);

[0017] Among them, V(x, y, θ) represents the potential at a single fastener on the pipeline caused by the stray current of the track; V s(x, y, θ) represents the pipeline potential corresponding to the track with coordinates (x, y) on the two-dimensional plane under the condition that the current leakage is reduced after increasing the track insulation enhancement measures, as shown in the following formula:

[0018]

[0019] Among them,

[0020]

[0021] are, respectively, the same number of calculation points taken on both sides of the origin of the S-axis after the track insulation enhancement treatment, that is, the calculation points on the positive half-axis and the negative half-axis of the origin;

[0022] x represents the longitudinal distance along the pipeline;

[0023] y represents the vertical distance between the line and the pipeline;

[0024] d is the average distance between two adjacent fasteners;

[0025] n s represents the number of fasteners with insulation enhancement measures;

[0026] ρ is the soil resistivity;

[0027] I s is the current leakage before the insulation enhancement transformation;

[0028] V o (x, y, θ) represents the pipeline potential corresponding to the track with coordinates (x, y) on the two-dimensional plane under the condition that no track insulation enhancement is carried out, and the formula is as follows:

[0029]

[0030] Among them,

[0031]

[0032] are, respectively, the same number of calculation points taken on both sides of the origin of the S-axis without the track insulation enhancement treatment, that is, the calculation points on the positive half-axis and the negative half-axis of the origin;

[0033] I o is the current leakage before the insulation enhancement transformation.

[0034] Furthermore: The specific estimation method of the S4 is as follows:

[0035] According to the rail-to-ground insulation level set for urban rail transit lines, following the principle of averaging, within a fixed range, the leakage current is evenly distributed on the rail, and stray current is generated at each fastener on the rail. The specific range is: 0.5 km, 1 km, 1.5 km. For the stray current generated evenly at each fastener, the pipeline length corresponding to every two adjacent fasteners is regarded as a section, and the influence on the pipeline is accumulated in a segmented integration manner, solving the problem that the influences of each section cannot be conveniently superimposed due to different partition insulation levels and geological conditions.

[0036] The present invention also provides a calculation system for the influence of urban rail stray current on the cross potential of pipelines, including: a terminal device;

[0037] The terminal device includes a memory, a processor, and a computer program stored in the memory and executable on the processor;

[0038] When the processor executes the computer program, it implements the steps of the method described in any one of the above.

[0039] The advantages of the present invention are as follows: fully considering various factors between urban rails and target pipelines, the size of the area affected by stray current in different sections can be viewed, and the insulation protection distance can be reasonably planned before insulation protection treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention and the prior art, the following will briefly introduce the drawings required for description in the embodiments and the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 It is a flow chart of the present invention;

[0042] Figure 2 It is a flow chart of the ground potential prediction of the SSIM-V model of the present invention;

[0043] Figure 3 It is a schematic diagram of the influence of the vertical distance on the ground potential of the present invention;

[0044] Figure 4 It is a schematic diagram of the influence of the cross angle on the ground potential of the present invention;

[0045] Figure 5 It is a schematic diagram of the influence of the soil resistivity on the ground potential of the present invention;

[0046] Figure 6 It is a schematic diagram of the influence of the insulation length on the ground potential of the present invention;

[0047] Figure 7 This is a spatial schematic diagram of the spatial positions of the target pipeline and the urban rail transit line of the present invention. Specific embodiments

[0048] In order to make the objectives, technical solutions and advantages of the present application clearer, the following describes and explains the present application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0049] Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without making creative efforts, the present application can also be applied to other similar scenarios based on these drawings. In addition, it can also be understood that although the efforts made in this development process may be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some designs, manufacturing or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be understood that the content disclosed in the present application is insufficient.

[0050] If there is no special instruction, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0051] Please refer to Figure 1 , which is a flowchart of the present invention and includes the following steps:

[0052] S1: Place the spatial positions of the target pipeline and the urban rail transit line in a three-dimensional space at the same time, and obtain the coordinate data of both to obtain the position information between them;

[0053] Specifically, use coordinate transformation to perform spatial conversion between geographical coordinates and three-dimensional coordinates to obtain the relative distances of each point between them; to provide the distance between a certain point on the urban rail transit line and a certain point on the target pipeline required for subsequent calculations.

[0054] S2: Then discard the vertical height of the spatial positions of the target pipeline and the urban rail transit line, perform a flat two-dimensionalization process, and place the two in the same plane; then match the various parameters measured on the actual track of the urban rail transit line to the corresponding positions on the track in the two-dimensional image. The parameters specifically include: soil resistivity, the installation positions and quantities of rail fasteners, the local insulation length and insulation level of the line;

[0055] Specifically, continue to perform flat two-dimensional processing on the spatial positions of the target pipeline and the urban rail transit line already in the three-dimensional space using coordinate transformation. For example, Figure 7 As shown: Obtain the included angle line information, that is, the included angle information between the target pipeline and the urban rail transit line on the same horizontal plane; then match the measured rail-to-ground transition resistance of the operating line, that is, the rail insulation level and the insulation level expected to be achieved in the preliminary design stage, the line local insulation length and insulation level in the model, the soil resistivity along the line between the measured target track and the target pipeline in the geological exploration data, and the physical information of the fasteners on the target track rail; all to the corresponding positions on the two lines projected by the target pipeline and the urban rail transit line on the two-dimensional plane, so as to facilitate the calculation and call of various parameters of the selected position when calculating the selected position.

[0056] S3: Construct an SSIM-V stray current single-factor ground potential influence evaluation model. According to the principle of averaging, further obtain its potential information based on the fact that the leakage current is evenly distributed at each fastener on the rail within a fixed range d to generate stray current;

[0057] Specifically: The SSIM-V stray current single-factor ground potential influence evaluation model is as follows:

[0058] V(x, y, θ) = V s (x, y, θ) + V o (x, y, θ);

[0059] Among them, V(x, y, θ) represents the potential at a single fastener on the pipeline caused by the stray current of the track; V s (x, y, θ) represents the pipeline potential corresponding to the track with coordinates (x, y) on the two-dimensional plane under the condition that the current leakage amount is reduced after increasing the track insulation enhancement measures. Specifically, it is shown by the following formula:

[0060]

[0061] Among them,

[0062]

[0063] are, respectively, after performing track insulation enhancement treatment, the same number of calculation points are taken on both sides of the origin of the S axis, that is, the calculation points on the positive half-axis and the negative half-axis of the origin;

[0064] x represents the longitudinal distance along the pipeline;

[0065] y represents the vertical distance between the line and the pipeline;

[0066] d is the average distance between two adjacent fasteners;

[0067] n s represents the number of fasteners with insulation enhancement measures;

[0068] ρ is the soil resistivity;

[0069] I s is the current leakage after insulation transformation;

[0070] V o (x, y, θ) represents the pipeline potential corresponding to the track with coordinates (x, y) on the two-dimensional plane under the condition of no track insulation enhancement. The formula is as follows:

[0071]

[0072] where,

[0073]

[0074] are respectively the same number of calculation points taken on both sides of the origin of the S axis under the condition of no track insulation enhancement treatment, that is, the calculation points on the positive half-axis and negative half-axis of the origin;

[0075] I o is the current leakage before insulation transformation.

[0076] S4: Estimation of the total influence range of the pipeline according to the potentials of each fastener on the rail;

[0077] Specifically, according to the rail-to-ground insulation level set for the urban rail transit line, following the principle of averaging, the leakage current is evenly distributed on the rails at each fastener within a fixed range to generate stray current. The ranges are specifically: 0.5 km, 1 km, 1.5 km. For the stray current generated by the evenly distributed fasteners, the pipeline length corresponding to every two adjacent fasteners is regarded as a section, and the influence on the pipeline is accumulated by using the method of sectional integration, solving the problem that the influences of each section cannot be reasonably superimposed due to different partition insulation levels and geological conditions.

[0078] Please refer to Figure 2 , the ground potential prediction flowchart of the SSIM-V model of the present invention. The main purpose is to estimate the influence range through various parameters, so as to adjust the line design.

[0079] A specific embodiment provided by the present invention:

[0080] Select a sample where both the target pipeline and the urban rail transit line are 2 km long, the projection intersection of the two is located at the midpoint of their length directions, the vertical distance y between the target pipeline and the urban rail transit line is in the range of [10 m, 30 m], the rail transition resistance is about 1 Ω - 15 Ω, the traction current I = 1000 A, the soil resistivity is 100 Ω / m, and the current intensity at each pair of fasteners IS = 10 ÷ 1680 A ≈ 0.006 A, Io = 100 ÷ 1680 A ≈ 0.06 A;

[0081] As Figures 3 - 6 shown, it is the specific evaluation of the influence of each factor on the potential:

[0082] Among them, the abscissa represents the positive and negative distances of the pipeline from the origin, and the origin is the midpoint of the projection intersection of the above two located at the midpoint of their length directions;

[0083] Figure 3 It is a schematic diagram of the influence of the vertical distance on the ground potential;

[0084] It can be seen that the farther the vertical distance between the target pipeline and the urban rail transit line, the smaller the potential, that is, the smaller the influence. However, in actual situations, the vertical distance between the pipeline and the urban rail transit line is in the range of [10 m, 30 m]. Here, when we select the vertical distance between the two to be 20 m, we calculate the change of the ground potential along the axial direction of the pipeline under different included angle conditions.

[0085] As Figure 4 shown, it is a schematic diagram of the influence of the intersection included angle of the present invention on the ground potential;

[0086] It can be known that when the included angle is between 0° and 30°, the ground potential along the axial direction of the pipeline increases rapidly with the decrease of the included angle, and a maximum value appears near the end position of the enhancement section; while when the angle is between 45° and 90°, the ground potential decreases slowly with the increase of the angle, and the decreasing amplitude shows a downward trend; therefore, when designing the track line, the included angle between the track and the pipeline should be increased as much as possible, and the included angle range between 45° and 90° is preferred;

[0087] Under Figure 3 and Figure 4 the selected conditions, that is, when the vertical distance between the target pipeline and the urban rail transit line is 20 m and the included angle between the target pipeline and the urban rail transit line in the projection plane is 30°, the influence of different soil resistivities on the ground potential is further studied; the soil resistivity ρ is respectively selected as 100 Ω·km, 200 Ω·km, 300 Ω·km, 400 Ω·km and 500 Ω·km. It can be known that with the increase of the soil resistivity, the ground potential at the same location will increase significantly; the soil conditions also determine the value of the ground potential at the pipeline, which has an important impact on the anti-corrosion protection of the pipeline here.

[0088] UnderFigure 3 , Figure 4 and Figure 5 Under the selected conditions, that is, the vertical distance between the target pipeline and the urban rail transit line is 20 m, the included angle between the target pipeline and the urban rail transit line in the projection plane is 30°, and the soil resistivity is usually 300 Ω·km, so 300 Ω·km is selected here;

[0089] The distribution of the ground potential along the pipeline with different enhanced insulation lengths of ±L is calculated, that is, the influence of the insulation length on the ground potential. As Figure 6 shown, it can be seen that when the insulation section length increases from the range of ±105 m to the range of ±735 m, the ground potential at the intersection of the two decreases from 5.56 V to 1.78 V, with a decrease amplitude of 3.78 V and a decrease rate of 68.0%; when the insulation length further increases to the range of ±1050 m (at this time, all the calculated tracks have taken measures of enhanced insulation), the ground potential drops to 1.12 V. Compared with 1.78 V in the range of ±735 m, the absolute value only decreases by 0.66 V. Thus, it can be seen that when the length of the insulation enhancement section exceeds the range of ±735 m, the ground potential hardly changes significantly. It can be known that under the crossing conditions, when the length of the insulation enhancement section is not less than the range of ±700 m, it can meet the need to protect the pipeline.

[0090] The above has made a very detailed application description of one or more embodiments of the present invention, but the content described is only a specific example of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All other methods and changes proposed based on the content of the present invention shall fall within the scope of the patent protection of the present invention.

Claims

1. A calculation method for the influence of urban rail stray current on the cross potential of pipelines, characterized in that It includes the following steps: S1: Place the spatial position of the target pipeline and the spatial position of the urban rail transit line in a three-dimensional space at the same time, and obtain the coordinate data of both to obtain the position information between them; S2: Then, discard the vertical height of the spatial position of the target pipeline and the spatial position of the urban rail transit line, perform a flat two-dimensional processing, and place the two in the same plane; then match the various parameters measured in the actual track of the urban rail transit line to the corresponding positions on the track in the two-dimensional image. The parameters specifically include: soil resistivity, the installation position and quantity of rail fasteners, the local insulation length and insulation level of the line; S3: Construct an SSIM-V stray current single-factor ground potential influence evaluation model. According to the principle of averaging, further obtain its potential information based on the fact that the leakage current is evenly distributed at each rail fastener within a fixed range d to generate stray current; S4: Estimate the total influence range of the potential of each rail fastener on the pipeline; In S3, the SSIM-V stray current single-factor ground potential influence evaluation model is as follows: ； Among them, represents the potential at a single fastener on the pipeline caused by the stray current in the track; It represents the pipeline potential corresponding to the track with coordinates (x, y) on the two-dimensional plane under the condition that the current leakage is reduced after the track insulation enhancement measures are taken, as shown in the following formula: ； Among them, ; ； They are respectively the calculation points with the same quantity taken on both sides of the origin of the S axis after the track insulation enhancement treatment, that is, the calculation points on the positive half-axis and the negative half-axis of the origin; x represents the longitudinal distance along the pipeline; y represents the vertical distance between the line and the pipeline; d is the average distance between two adjacent fasteners; Indicates the number of fasteners with insulation enhancement measures; is the soil resistivity; is the current leakage of the insulation-reinforced line; It represents the pipeline potential corresponding to the orbit with coordinates (x, y) on the two-dimensional plane under the condition of no enhanced orbital insulation. The formula is as follows: ； Among them, ; ； They are respectively the calculation points with the same quantity taken on both sides of the origin of the S axis without the track insulation enhancement treatment, that is, the calculation points on the positive half-axis and the negative half-axis of the origin; The line current leakage of the line without insulation enhancement transformation.

2. The calculation method for the influence of urban rail stray current on the cross potential of pipelines according to claim 1, characterized in that The specific principle of S1 is: Use coordinate transformation to perform spatial conversion between geographical coordinates and three-dimensional coordinates on the design drawings of the urban rail transit line and the pipeline at the same time to obtain the relative distance between them.

3. The calculation method for the influence of stray current of urban rail on the cross potential of pipelines according to claim 1, characterized in that, The principle of S2 is: Use coordinate transformation to continue to perform flat two-dimensional processing on the spatial position of the target pipeline and the spatial position of the urban rail transit line that are already in the three-dimensional space to obtain the included angle line information; then match the measured rail-to-ground transition resistance of the operating line, that is, the rail insulation level and the insulation level expected to be achieved in the preliminary design stage, to the local insulation length and insulation level in the model, the soil resistivity along the line between the target track and the target pipeline measured by the geological exploration data, and the physical information of the fasteners on the target track rails; all are matched to the two-dimensional plan for convenient operation and call.

4. The calculation method for the influence of stray current of urban rail on the cross - ground potential of pipelines according to claim 1, wherein, For S4, the estimation method is specifically: According to the rail-to-ground insulation level set for the urban rail transit line, and in accordance with the principle of averaging, the leakage current is evenly distributed on each rail fastener within a fixed range to generate stray current. The range is specifically: 0.5 km, 1 km, 1.5 km. For the stray current generated by the even distribution at each fastener, regard the pipeline length corresponding to every two adjacent fasteners as a section, and use the method of segmented integration to accumulate the influence on the pipeline, solving the problem that the influence of each section cannot be conveniently superimposed due to different partition insulation levels and geological conditions.

5. A calculation system for the influence of urban rail stray current on the cross potential of pipelines, characterized in that, It includes: A terminal device; The terminal device includes a memory, a processor, and a computer program stored in the memory and operable on the processor; When the processor executes the computer program, the steps of the method according to any one of claims 1-4 are implemented.

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