Detection method of coupling relationship between subway and oil and gas pipeline

Abstract

The invention discloses a method for detecting the coupling relationship between a subway and an oil and gas pipeline, comprising the steps of: acquiring parameters of the subway and the oil and gas pipeline; arranging detection points, copper sulfate reference electrodes, auxiliary voltage electrodes, and voltage measurement leads, and calculating the inductive coupling coefficient between the subway and the oil and gas pipeline and the coupling coefficient of the voltage withstanding voltage of the oil and gas pipeline insulation coating according to the acquired voltage; the method can acquire the relationship between the subway traction current and the interference voltage on the oil and gas pipeline, and can not only measure the interference degree of the subway on the oil and gas pipeline at the current stage, but also be used to estimate the interference voltage generated on the oil and gas pipeline under different subway loads.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic compatibility, and in particular relates to a method for detecting the coupling relationship between a subway and an oil and gas pipeline. Background Art

[0002] With the rapid development of my country's economy, the distribution of urban subway networks in my country is becoming more and more extensive. Since the subway traction power supply system uses rails and the earth as the return path, there will be stray currents in the ground during normal operation. The power supply system can also interfere with the adjacent buried pipelines through electromagnetic coupling in space and resistive coupling through the earth. When the DC transmission system or subway is in operation, if a part of the current flows into the earth, it will cause changes in the surface potential distribution, interfere with the cathodic protection system of the oil and gas pipeline, and in severe cases, damage to the pipeline insulation coating and metal corrosion of the pipeline wall. The AC system can also generate induced voltage on the pipeline, affecting the normal operation of the cathodic protection system, and may also cause damage to the pipeline insulation coating. In recent years, DC or low-frequency bias voltages have been measured on oil and gas pipelines near subways, which have adverse effects on the stable operation, economic benefits and personnel safety of the pipeline system. However, there is still a lack of measurement and evaluation methods to evaluate the degree of coupling between subways and oil and gas pipelines. Summary of the invention

[0003] In order to overcome the above technical defects, the present invention provides a method for detecting the coupling relationship between a subway and an oil and gas pipeline, which can detect the coupling relationship between a subway and an oil and gas pipeline.

[0004] In order to solve the above problems, the present invention adopts the following solutions:

[0005] A method for detecting the coupling relationship between a subway and an oil and gas pipeline comprises the following steps:

[0006] Get the parameters of subways and oil and gas pipelines;

[0007] Selecting a pipeline voltage test pile as the first detection point and the second detection point of the coupling relationship, and setting a copper sulfate reference electrode at the first detection point and the second detection point respectively;

[0008] A vertical line of the subway line is made from the first detection point, and a vertical line of the subway line is made from the second detection point; auxiliary voltage electrodes are arranged on the extension lines in the opposite directions of the two vertical lines, and voltage measurement leads are arranged from the first detection point and the second detection point to the auxiliary voltage electrodes;

[0009] Obtain a first voltage and a second voltage from the auxiliary voltage pole to the pipeline voltage test pile, and obtain a third voltage and a fourth voltage from the test pile to the copper sulfate reference electrode;

[0010] In a first time period, a plurality of maximum first voltages and a plurality of maximum second voltages are screened out, a first average value of the first voltage and a first average value of the second voltage are calculated, and a first actual induced voltage of the oil and gas pipeline is calculated by the first average value of the first voltage and the first average value of the second voltage;

[0011] In the second time period, a plurality of maximum first voltages and a plurality of maximum second voltages are screened out, a second average value of the first voltage and a second average value of the second voltage are calculated, and a second actual induced voltage of the oil and gas pipeline is calculated by the second average value of the first voltage and the second average value of the second voltage;

[0012] In the second time period, the maximum load current of the traction substation is obtained, and the inductive coupling coefficient between the subway and the oil and gas pipeline is calculated according to the maximum load current, the first actual induced voltage of the oil and gas pipeline, and the second actual induced voltage of the oil and gas pipeline;

[0013] In a first time period, a plurality of maximum third voltages and a plurality of maximum fourth voltages are screened out, and a first average value of the third voltage and a first average value of the fourth voltage are calculated;

[0014] In the second time period, a plurality of maximum third voltages and a plurality of maximum fourth voltages are screened out, and a second average value of the third voltages and a second average value of the fourth voltages are calculated;

[0015] The coupling coefficient of the voltage withstanding voltage of the insulating coating of the oil and gas pipeline is calculated according to the second average value of the third voltage and the second average value of the fourth voltage.

[0016] As a further improvement of the present invention, the parameters include: the location of the subway and the oil and gas pipeline, the buried depth of the oil and gas pipeline, and the buried depth of the subway line tunnel. The location of the subway line and the oil and gas pipeline, and the location of the nearest point of the oil and gas pipeline to the subway are marked on the map.

[0017] As a further improvement of the present invention, the step of selecting the pipeline voltage test pile as the first detection point and the second detection point of the coupling relationship, and setting a copper sulfate reference electrode at the first detection point and the second detection point respectively, comprises the following steps:

[0018] Search from the point where the oil and gas pipeline is closest to the subway to both sides, and find the location point where the oil and gas pipeline is 1 km away from the subway on both sides. Select a nearby pipeline voltage test pile for each location point as the first detection point and the second detection point for coupling relationship detection;

[0019] A copper sulfate reference electrode is arranged within 1 meter of the first detection point and the second detection point.

[0020] As a further improvement of the present invention, a wave recording device is used to obtain the first voltage and the second voltage from the auxiliary voltage pole to the pipeline voltage test pile, and to obtain the third voltage and the fourth voltage from the test pile to the copper sulfate reference electrode.

[0021] As a further improvement of the present invention, when the oil and gas pipeline is perpendicular to the subway line, the voltage measurement leads from the first detection point and the second detection point to the auxiliary voltage pole are at an angle of 45° to the oil and gas pipeline and are set in a direction away from the subway line with a length greater than or equal to 1 km.

[0022] As a further improvement of the present invention, the maximum load current of the traction substation is: the maximum load current of the traction substation at the time corresponding to a plurality of maximum first voltage values ​​and a plurality of second voltage values ​​in the second time period.

[0023] Compared with the prior art, the present invention has the following beneficial effects: the relationship between the subway traction current and the interference voltage on the oil and gas pipeline can be obtained, which can not only measure the interference degree of the subway on the oil and gas pipeline at the current stage, but also be used to estimate the interference voltage generated on the oil and gas pipeline under different subway loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0025] Figure 1 The measurement wiring diagram of the detection method described in Example 1;

[0026] Figure 2 This is a schematic diagram of a section of oil and gas running parallel to a subway line in Example 1;

[0027] Figure 3 for Figure 2 Distribution diagram of induced voltage on the pipeline in the middle section;

[0028] Figure 4 for Figure 2 Ground potential distribution diagram of pipeline in the middle section;

[0029] Figure 5 for Figure 2 Voltage distribution diagram of pipeline coating in the middle section.

[0030] Marking instructions: 1. Railway line; 2. Oil and gas pipeline; 3. Boundary of 1km from subway line; 4. Voltage test pile; 5. Copper sulfate reference electrode; 6. Auxiliary voltage electrode; 7. Voltage measurement lead; 8. Wave recording device. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0032] Example 1

[0033] According to Article 4.1.1 of GB / T 50698-2011 Technical Standard for AC Interference Protection of Buried Steel Pipelines, "When the distance between the pipeline and the high-voltage AC transmission line or AC electrified railway is greater than 1000m, no interference investigation test is required; when the pipeline is close to a 110kV or higher high-voltage AC transmission line, whether an interference investigation test is required can be determined according to the relative relationship diagram between the extreme proximity section length and the distance between the pipeline and the high-voltage AC transmission line". Therefore, this embodiment is used to detect the coupling coefficient of the oil and gas pipeline within 1000m of the distance between the subway line.

[0034] Through research, it is found that the electromagnetic influence of AC transmission lines on buried metal pipelines can be divided into three categories from the mechanism point of view: inductive coupling influence, resistive coupling influence and capacitive coupling influence.

[0035] Inductive coupling means that when an alternating current flows through a transmission line, an alternating magnetic field will be generated around the conductor, and this magnetic field exists in both the air and the earth. When a buried metal pipeline and a transmission line are close, the alternating magnetic field will generate a longitudinal electromotive force on the pipeline through electromagnetic induction.

[0036] Resistive coupling means that if a transmission line is short-circuited to the ground, part of the short-circuit current will flow into the earth. The current diffuses to infinity in the soil, and when passing through the buried metal pipeline, a certain potential rise will also be generated on the pipeline.

[0037] Capacitive coupling means that voltage is applied to the conductor of the high-voltage AC transmission line, and there is an electric field around it. Due to electrostatic induction or capacitive coupling, a ground potential will be induced on the pipeline.

[0038] Considering that the subway line is located underground, the soil is conductive and has a good shielding effect on the electric field. Therefore, the capacitive coupling effect between the subway and the oil and gas pipeline is ignored in the present invention. Only the inductive coupling and resistive coupling between the subway and the oil and gas pipeline are considered. The induced voltage caused by the subway on the oil and gas pipeline and the voltage on the coating are detected, and the induced voltage coupling coefficient K is calculated. 1 and the voltage withstand coefficient K on the coating 2 .

[0039] The technical principle of this embodiment to achieve the above purpose is to use the distribution law of the induced voltage on the oil and gas pipeline and the generation mechanism of the voltage on the coating.

[0040] A method for detecting a coupling relationship between a subway and an oil and gas pipeline in this embodiment includes the following steps:

[0041] S1. Obtain parameters of the subway and the oil and gas pipeline, wherein the parameters include: the location of the subway and the oil and gas pipeline, the buried depth of the oil and gas pipeline, and the buried depth of the subway line tunnel. Mark the location of the subway line and the oil and gas pipeline, and the location of the oil and gas pipeline to the subway at the nearest point on the map. In this embodiment, the parallel length of the subway and the oil and gas pipeline is 600m, the left side gradually moves away from the subway line, and the right side is perpendicular to the subway line. The oil and gas pipeline to the subway at the nearest point is a 600m parallel section.

[0042] S2. Select a pipeline voltage test pile as the first detection point and the second detection point of the coupling relationship, and set a copper sulfate reference electrode at the first detection point and the second detection point respectively.

[0043] Specifically, Figure 1 As shown, search from the point where the oil and gas pipeline is closest to the subway to both sides, and find the location points on both sides where the oil and gas pipeline is 1 km away from the subway. For each location point, select a nearby pipeline voltage test pile as the first detection point and the second detection point for coupling relationship detection; arrange a copper sulfate reference electrode within 1 meter of the first detection point and the second detection point.

[0044] exist Figure 1 A line with a distance of 1 km from the subway has been drawn. The line has two intersections with the oil and gas pipeline. The left intersection is the first detection point of this embodiment, and the right intersection is the second detection point of this embodiment. A copper sulfate reference electrode is arranged at a position 1m away from each of the two detection points.

[0045] S3, such as Figure 2 As shown (the vertical axis in the figure is the induced voltage on the pipeline, the unit is: V, the horizontal axis is Figure 1 The left end of the middle pipeline is taken as point 0, and the length of the right pipeline to point 0 is measured in meters. A vertical line of the subway line is made from the first detection point, and a vertical line of the subway line is made from the second detection point. Auxiliary voltage electrodes are arranged on the opposite extension lines of the two vertical lines at a distance of 1 km from the first detection point and the second detection point, and voltage measurement leads are arranged from the first detection point and the second detection point to the auxiliary voltage electrodes. Among them, the auxiliary voltage electrode is a metal probe with a length of not less than 40 cm and a diameter of not less than 1.2 cm, and the depth of the probe driven into the ground is not less than 20 cm.

[0046] When the oil and gas pipeline is perpendicular to the subway line, the voltage measurement leads from the first detection point and the second detection point to the auxiliary voltage pole have an angle of 45° with the oil and gas pipeline and are set in a direction away from the subway line with a length greater than or equal to 1 km.

[0047] S4. Obtaining the first voltage U from the auxiliary voltage pole to the pipeline voltage test pile 11 , the second voltage U 21 , obtain the third voltage U from the test pile to the copper sulfate reference electrode 12, the fourth voltage U 22 .

[0048] In step S4, a wave recording device may be used to obtain a first voltage U from the auxiliary voltage pole to the pipeline voltage test pile. 11 , the second voltage U 21 , obtain the third voltage U from the test pile to the copper sulfate reference electrode 12 , the fourth voltage U 22 .

[0049] Each recording device is timed by satellite, and the clock error of each recording device is no more than 1ms. The recording device used is required to be able to continuously record voltage waveforms, with a measurement bandwidth ≥20M, a recording sampling frequency of no less than 4kHz, no less than 2 recording channels, and a recording storage time of no less than 24 hours. The bandwidth of the voltage attenuation probe used is ≥20M, which can meet the requirements when the sampling frequency is no less than 4kHz, and the voltage resistance level is no less than 2000V.

[0050] S5. In the time period from 6:00 to 23:00, select the three largest first voltages U 11 , the three largest second voltages U 21 , calculate the first average value of the first voltage a first average value of the second voltage The first average value of the first voltage a first average value of the second voltage Calculate the first actual induced voltage U of the oil and gas pipe 1 ,like Figure 3 As shown (the vertical axis is the ground potential at the pipeline, the unit is: V, the horizontal axis is Figure 1 The left end of the pipeline has a zero point position, and the right end of the pipeline has a degree from the zero point position, in meters, U 1 Calculated by the following formula:

[0051]

[0052] In this embodiment, and is 21V and 13V, with a phase difference of 180°, so U 1 It is 34V.

[0053] S6. In the time period from 1:00 to 4:00, select several maximum first voltages U 11 , several maximum second voltages U 21 , calculate the second average value of the first voltage a second average value of the second voltage The second average value of the first voltage a second average value of the second voltage Calculate the second actual induced voltage U of the oil and gas pipe 1 ',like Figure 3 As shown, U′ 1 Calculated by the following formula:

[0054]

[0055] In this embodiment, and It is about 6V and 4V, the phase difference is 0°, and U′ is calculated 1 is 2V.

[0056] S7. In the time period from 1:00 to 4:00, the maximum load current I of the traction substation is obtained. According to the maximum load current I and the first actual induced voltage U of the oil and gas pipeline, 1 and the second actual induced voltage U′ of the oil and gas pipe 1 , calculate the inductive coupling coefficient K between the subway and the oil and gas pipeline 1 .

[0057] K 1 =(U 1 -U′ 1 ) / I

[0058] The maximum load current I of the traction substation is: By looking up the subway operation data of the day, the three largest first voltage values ​​U in the time period from 1:00 to 4:00 11 , three second voltage values ​​U 21 The maximum load current of the traction substation at the corresponding time.

[0059] In this embodiment, the maximum load current of the traction substation is I=1200A, and the inductive coupling coefficient K is calculated. 1 =0.0267. According to this coefficient, when the future maximum load current rises to 2000A, it can be estimated that the maximum induced voltage at this time is about 55.4V.

[0060] S8. In the time period from 6:00 to 23:00, select several largest third voltages U 12 , the maximum fourth voltage U 22 , calculate the third voltage U 12 , the fourth voltage U 22 The first average value U 2 ,like Figure 5 As shown (the vertical axis is the voltage that the pipeline coating withstands, the unit is: V, the horizontal axis is Figure 1 The left end of the pipeline is the 0-point position, and the length of the right pipeline to the 0-point position is in meters. In this embodiment, U 2 =26V.

[0061] S9. In the time period from 1:00 to 4:00, select the three largest third voltages U 12 , the three largest fourth voltages U 22 , calculate the third voltage U 12 , the fourth voltage U 22 The second average value U 2 ′ In this embodiment, U 2 ′ =2V.

[0062] S10, according to the first average value U 2 , the second average value U 2 ′ , calculate the coupling coefficient K of the voltage withstanding of the oil and gas pipeline insulation coating 2 :

[0063] K 2 =(U 2 -U′ 2 ) / I

[0064] K is calculated by the above formula 2 =0.02. According to this coefficient, when the long-term maximum load current rises to 2000A, it can be estimated that the maximum pipeline insulation coating withstand voltage is about 40V.

[0065] Through the above method, the coupling coefficient between the oil and gas pipeline and the subway line, as well as the electromagnetic interference intensity generated by the subway line in the oil and gas pipeline can be directly detected, including the induced voltage amplitude generated on the oil and gas pipeline, and the voltage amplitude borne by the insulation layer of the oil and gas pipeline wall caused by the subway.

[0066] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for detecting the coupling relationship between subway and oil and gas pipeline, It is characterized in that Includes steps: Obtain parameters of subways and oil and gas pipelines; Search from the point where the oil and gas pipeline is closest to the subway to both sides, and find the location point where the oil and gas pipeline is 1 km away from the subway on both sides. For each location point, select a nearby oil and gas pipeline voltage test pile as the first detection point and the second detection point for coupling relationship detection, and set a copper sulfate reference electrode at the first detection point and the second detection point; Draw a perpendicular line of the subway line from the first detection point, and draw a perpendicular line of the subway line from the second detection point; Auxiliary voltage electrodes are arranged on the extension lines in the opposite directions of the two vertical lines, and voltage measurement leads from the first detection point and the second detection point to the auxiliary voltage electrodes are arranged respectively; Obtaining a first voltage and a second voltage from the auxiliary voltage pole to the oil and gas pipeline voltage test pile, and obtaining a third voltage and a fourth voltage from the test pile to the copper sulfate reference electrode; In a first time period, a plurality of maximum first voltages and a plurality of maximum second voltages are screened out, a first average value of the first voltages and a first average value of the second voltages are calculated, and a first actual induced voltage of the oil and gas pipeline is calculated by the first average value of the first voltages and the first average value of the second voltages; In a second time period, a plurality of maximum first voltages and a plurality of maximum second voltages are screened out, a second average value of the first voltages and a second average value of the second voltages are calculated, and a second actual induced voltage of the oil and gas pipeline is calculated by the second average value of the first voltages and the second average value of the second voltages; In the second time period, the maximum load current of the traction substation is obtained, and the inductive coupling coefficient between the subway and the oil and gas pipeline is calculated according to the maximum load current, the first actual induced voltage of the oil and gas pipeline, and the second actual induced voltage of the oil and gas pipeline; In a first time period, a plurality of maximum third voltages and a plurality of maximum fourth voltages are screened out, and a first average value of the third voltage and the fourth voltage is calculated; In the second time period, a plurality of maximum third voltages and a plurality of maximum fourth voltages are screened out, and a second average value of the third voltage and the fourth voltage is calculated; The coupling coefficient of the voltage withstanding of the insulating coating of the oil and gas pipeline is calculated according to the first average value and the second average value.

2. The detection method according to claim 1, It is characterized in that Parameters include: The location of the subway and the oil and gas pipeline, the buried depth of the oil and gas pipeline, and the buried depth of the subway line tunnel. Mark the location of the subway line and the oil and gas pipeline, and the nearest point of the oil and gas pipeline to the subway on the map.

3. The detection method according to claim 2, It is characterized in that The copper sulfate reference electrode is respectively provided at the first detection point and the second detection point, specifically: A copper sulfate reference electrode is arranged within 1 meter of the first detection point and the second detection point.

4. The detection method according to claim 1, It is characterized in that A wave recording device is used to obtain a first voltage and a second voltage from the auxiliary voltage electrode to the oil and gas pipeline voltage test pile, and a third voltage and a fourth voltage from the test pile to the copper sulfate reference electrode.

5. The detection method according to claim 1, It is characterized in that When the oil and gas pipeline is perpendicular to the subway line, the voltage measurement leads from the first detection point and the second detection point to the auxiliary voltage pole have an angle of 45° with the oil and gas pipeline and are set in a direction away from the subway line with a length greater than or equal to 1 km.

6. The detection method according to claim 1, It is characterized in that The maximum load current of the traction substation is: the maximum load current of the traction substation at the time corresponding to a plurality of maximum first voltage values ​​and a plurality of second voltage values ​​in the second time period.

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