A subway stray current testing system and method

Abstract

The present invention discloses a subway stray current test system and method thereof, the current test system comprises: a track bed simulation part, used to simulate the subway track bed; an adjustable resistor, whose first end is connected to the track bed simulation part, used to simulate the resistance value when the track bed length changes in the actual field environment; a DC adjustable power supply, whose first end is connected to the second end of the adjustable resistor, used to provide a test power supply; a current test component, whose first end is connected to the second end of the DC adjustable power supply, and the second end of the current test component is connected to the track bed simulation part, used to measure the current value flowing through the track bed simulation part; a voltage test component, whose first end is connected to the second end of the current test component, and the second end of the voltage test component is connected to the first end of the adjustable resistor, used to measure the voltage value at both ends of the track bed simulation part. It can highly simulate the subway field environment, and is convenient for testing the subway stray current leakage and corrosion risk.

Description

Technical Field

[0001] The invention belongs to the technical field of stray current corrosion and protection, and in particular relates to a subway stray current testing system and method. Background Art

[0002] Stray current refers to current that flows outside the specified circuit or intention. In the DC traction system of the subway, stray current is widely present and has a relatively serious negative impact. Relevant studies have shown that stray current will cause electrochemical corrosion to metal structures such as steel bars in the concrete main structure of the subway system and metal pipelines buried underground, which will not only shorten the service life of the metal structure, but also reduce the strength and durability of the main structure in the subway system, and even cause serious accidents. Therefore, it is necessary to effectively and accurately evaluate the level of stray current leakage and its corrosion risk at the subway site.

[0003] Due to the complex on-site environment of the subway, many key parameters are difficult to measure or accurately measure. It is necessary to build an experimental system that can simulate the on-site environment of the subway to test the level of stray current leakage and its corrosion risk. Summary of the invention

[0004] In order to overcome the above technical defects, the present invention provides a subway stray current testing method and system, which can highly simulate the subway on-site environment and facilitate the testing of subway stray current leakage and corrosion risk.

[0005] In order to solve the above problems, the present invention is implemented according to the following technical solutions:

[0006] A subway stray current testing system, comprising:

[0007] Track bed simulation parts, used to simulate subway track bed;

[0008] An adjustable resistor, a first end of which is connected to the ballast simulation component and is used to simulate the resistance value when the ballast length changes in an actual field environment;

[0009] A DC adjustable power supply, a first end of which is connected to the second end of the adjustable resistor, for providing a test power supply;

[0010] A current test component, a first end of which is connected to the second end of the DC adjustable power supply, and a second end of the current test component is connected to the ballast bed simulation component, for measuring the current value flowing through the ballast bed simulation component;

[0011] A voltage testing component, a first end of which is connected to the second end of the current testing component, and a second end of which is connected to the first end of the adjustable resistor, is used to measure the voltage value at both ends of the track bed simulation component.

[0012] Compared with the prior art, the test system of the present invention has the following beneficial effects: a roadbed simulation component is used to simulate the height of the subway roadbed in the actual subway site environment; and with the adjustable resistor, the resistance change when the length of the roadbed changes in the actual site environment can be simulated to meet the simulation of subway roadbeds at various lengths; when the reading of the voltage test component is consistent with the voltage at both ends of the actual subway roadbed, the current value obtained by the current test component can provide data support for the stray current leakage level and corrosion assessment.

[0013] As a further improvement of the present invention, the roadbed simulation component comprises: a concrete layer, a rail group, a drainage net and an insulating fastener device;

[0014] The drainage net is arranged in the concrete layer, and the rail set is fixed above the concrete layer by the insulating fastener device.

[0015] As a further improvement of the present invention, the current testing assembly includes: a first ammeter, the rail group includes a first rail and a second rail, the first end of the adjustable resistor is connected to the first end of the first rail and the first end of the second rail, the first end of the first ammeter is connected to the second end of the DC adjustable power supply, and the second end of the first ammeter is connected to the second end of the first rail and the second end of the second rail.

[0016] As a further improvement of the present invention, the current testing assembly includes: a second ammeter, the drainage network is provided with a busbar extending to the outside of the supporting layer, the first end of the second ammeter is connected to the second end of the DC adjustable power supply, and the second end of the second ammeter is connected to the busbar.

[0017] As a further improvement of the present invention, the current testing component includes: a third ammeter, the concrete layer is provided with a current measuring terminal extending outward, the first end of the third ammeter is connected to the second end of the DC adjustable power supply, and the second end of the third ammeter is connected to one of the measuring terminals.

[0018] As a further improvement of the present invention, the voltage testing component is a voltmeter, and a plurality of voltage testing terminals are also provided on the concrete layer;

[0019] The first end of the voltmeter is connected to the second end of the first ammeter, and the second end of the voltmeter is connected to the first end of the adjustable resistor;

[0020] Or the first end of the voltmeter is connected to the second end of the first ammeter, and the second end of the voltmeter is connected to the voltage test terminal.

[0021] In addition, the present invention also provides a subway stray current testing method, including the above-mentioned testing system, and the testing method includes the following steps:

[0022] S1. Key parameters of test trackbed simulation parts;

[0023] S2. Calculate the potential distribution law of the subway rails according to the key parameters;

[0024] S3, selecting a first length of the actual track bed at the subway site as an experimental interval;

[0025] S4, calculating the potential values ​​at both ends of the experimental interval;

[0026] S5, adjusting the DC adjustable power supply and the adjustable resistor so that the reading of the voltage test component is equal to the potential value;

[0027] S6. Read the current value of the current testing component.

[0028] As a further improvement of the present invention, after step S6, the present invention further comprises the following steps:

[0029] S7, changing the connection position between the second end of the voltage testing component and the track bed simulation component, and sequentially acquiring a plurality of the voltage values;

[0030] S8. Calculate the potential gradient according to the multiple voltage values.

[0031] As a further improvement of the present invention, the track bed simulation component is provided with a plurality of spring bars, baffle seats, and rubber pads, and after step S8, the following steps are also included:

[0032] S91, replace the elastic bars, the baffle seats, and the rubber pads with different resistivities in sequence, repeat steps S6 to S8, and calculate the current value and potential gradient when the resistivity of the insulating fastener changes.

[0033] As a further improvement of the present invention, the roadbed simulation part has a concrete layer, and after step S8, the following steps are further included:

[0034] S92, spraying water onto the concrete layer to change the humidity of the concrete layer, repeating steps S6 to S8, and calculating the current value and potential gradient when the resistivity of the insulating fastener changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0036] Figure 1 This is a schematic diagram of the overall structure of the test system described in Example 1;

[0037] Figure 2 Another schematic diagram of the overall structure of the test system described in Example 1;

[0038] Figure 3 This is a schematic structural diagram of the insulating fastener device described in Example 1;

[0039] Figure 4 This is a schematic diagram of the structure of the drainage network described in Example 1;

[0040] Figure 5 This is a schematic diagram of the potential gradient test described in Example 2.

[0041] Marking instructions: 1. Ballast bed simulation; 11. Concrete layer; 111. Hydraulic bearing layer; 112. Cement emulsified asphalt mortar adjustment layer; 113. Track plate layer; 12. Rail group; 121. First rail; 122. Second rail; 13. Drainage net; 131. Transverse reinforcement; 132. Longitudinal reinforcement; 133. Bus bar; 14. Insulating fastener device; 141. Pad; 142. Spring bar; 143. First fixing piece; 144. Baffle seat; 145. Second fixing piece; 15. Current measuring terminal; 16. Voltage measuring terminal; 2. Adjustable resistor; 3. DC adjustable power supply; 4. Current test assembly; 41. First ammeter; 42. Second ammeter; 43. Third ammeter; 5. Voltmeter. DETAILED DESCRIPTION

[0042] 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.

[0043] Example 1

[0044] This embodiment discloses a system for testing subway stray current leakage level and corrosion risk. Figure 1 As shown, it includes: a track bed simulation component 1, an adjustable resistor 2, a DC adjustable power supply 3, a current test component 4 and a voltage test component, wherein the track bed simulation component 1 is used to simulate the subway track bed; the first end of the adjustable resistor 2 is connected to the track bed simulation component 1, and is used to simulate the resistance change when the track bed length changes in the actual field environment; the negative pole of the DC adjustable power supply 3 is connected to the second end of the adjustable resistor 2, and is used to provide a test power supply, and the voltage adjustment range of the DC adjustable power supply 3 is 0-200V, and the current adjustment range is 0-20A; the positive terminal of the current test component 4 is connected to the positive pole of the DC adjustable power supply 3, and the negative terminal of the current test component 4 is connected to the track bed simulation component 1, and is used to measure the current value flowing through the track bed simulation component 1; the first end of the voltage test component is connected to the second end of the current test component 4, and the second end of the voltage test component is connected to the first end of the adjustable resistor 2, and is used to measure the voltage value at both ends of the track bed simulation component 1.

[0045] In the above embodiment, the roadbed simulation component 1 includes: a concrete layer 11, a rail group 12, a drainage net 13 and an insulating fastener device 14; wherein, the concrete layer 11 includes: a hydraulic supporting layer 111, a cement emulsified asphalt mortar adjustment layer 112 and a track plate layer 113, the cement emulsified asphalt mortar adjustment layer 112 is arranged on the hydraulic supporting layer, the drainage net 13 is arranged inside the hydraulic supporting layer 111, and the rail group 12 is arranged on the track plate layer 113.

[0046] Furthermore, the length of the concrete layer 11 is 5.5 meters, the height of the hydraulic support layer 111 is 300 mm, the height of the cement emulsified asphalt mortar adjustment layer 112 is 30 mm, and the height of the track plate is 240 mm.

[0047] In the above embodiment, the current test assembly 4 includes: a first ammeter 41, a rail group 12 includes a first rail 121 and a second rail 122, a first end of the adjustable resistor 2 is connected to a first end of the first rail 121 and a first end of the second rail 122, a first end of the first ammeter 41 is connected to a second end of the DC adjustable power supply 3, and a second end of the first ammeter 41 is connected to a second end of the first rail 121 and a second end of the second rail 122 to form a loop, and the first ammeter 41 is used to measure the loop current Ia. In the entire loop, since the resistivity of the rail is very low, the high-power adjustable resistor 2 simulates the voltage drop value of the rail potential on the corresponding length in the actual subway site environment.

[0048] More specifically, the first rail 121 and the second rail 122 are both 60 rails with a length of 5 m, and the gauge of the two rails is 1445 m.

[0049] In the above embodiment, the current testing assembly 4 includes: a second ammeter 42, the drainage network 13 is provided with a busbar 133 extending to the outside of the supporting layer, the first end of the second ammeter 42 is connected to the second end of the DC adjustable power supply 3, the second end of the second ammeter 42 is connected to the busbar 133, and the second ammeter 42 is used to measure the current Ib collected by the drainage network 13.

[0050] In the above embodiment, the current testing assembly 4 includes: a third ammeter 43, a current measuring terminal 15 extending outward is provided on the hydraulic supporting layer 111, a first end of the third ammeter 43 is connected to the second end of the DC adjustable power supply 3, and a second end of the third ammeter 43 is connected to one of the measuring terminals, and the third ammeter 43 is used to measure the uncollected stray current Ic; at the same time, the measuring terminal is also used to measure the surface potential gradient near the rail along the direction of the rail, so as to perform corrosion risk assessment.

[0051] Based on this, the stray current leakage of the experimental section and the collection efficiency of the drainage net 13 can be calculated by measuring the loop current Ia, the current collected by the drainage net 13 Ib and the uncollected stray current Ic, providing a reference for the stray current leakage level under the actual working conditions corresponding to the simulated environment. The stray current leakage is Ib+Ic, and the collection efficiency of the drainage net 13 can be expressed as:

[0052]

[0053] In the above embodiment, the voltage testing component is a voltmeter 5 , a first end of the voltmeter 5 is connected to a second end of the first ammeter 41 , and a second end of the voltmeter 5 is connected to a first end of the adjustable resistor 2 .

[0054] After obtaining the measurement loop current Ia, the current Ib collected by the drainage network 13, and the uncollected stray current Ic, the reserved voltage measurement terminal 116 can be used to measure the surface potential gradient along the rail direction. At this time, the first end of the voltmeter 5 is connected to the second end of the first ammeter 41, and the second end of the voltmeter 5 is connected to the voltage measurement terminal 116. Figure 2 shown.

[0055] In the above embodiment, if Figure 3 As shown, the insulating fastener includes: a pad 141, an elastic bar 142, a first fixing member 143, a baffle seat 144 and a second fixing member 145; the pad 141 is arranged between the track group and the concrete layer 11, the elastic bar 142 is flippably arranged on the track group, the baffle seat 144 is arranged on the pad 141 through the first fixing member 143 and is located beside the track group, the second fixing member 145 penetrates the elastic bar 142 and is connected to the baffle seat 144 to press the track group onto the concrete layer 11, and this embodiment uses 7 groups of insulating fasteners.

[0056] In the above embodiment, if Figure 4 As shown, the drainage net 13 includes: a plurality of transverse steel bars 131 and a plurality of longitudinal steel bars 132, the transverse steel bars 131 and the longitudinal steel bars 132 are cross-arranged to form a drainage net 13 with a mesh structure; 1329 longitudinal steel bars 13, with a diameter of 15mm, 1317 transverse steel bars 13, with a diameter of 25mm, the longitudinal steel bars 132 are spaced 220mm apart, and the transverse steel bars 131 are spaced 300mm apart.

[0057] Example 2

[0058] This embodiment provides a method for testing subway stray current leakage level and corrosion risk, using the subway stray current testing system of Embodiment 1. The specific structure thereof is shown in Embodiment 1 and will not be described in detail here. The testing method includes the following steps:

[0059] S1. Before testing, test the key parameters of the ballast simulation component 1, including the resistivity of the insulating fastener, the rail-to-ground transition resistance, the longitudinal resistance of the rail, the resistivity of the concrete, and other key parameters; during the test, adjust the resistance value of the adjustable resistor 2 to the maximum, and the resistivity of the concrete can be measured by the reserved measurement terminals using the four-pole method;

[0060] S2. Calculate the potential distribution of the rails at the subway site based on key parameters;

[0061] S3. Select 5 meters of the actual track bed at the subway site as the experimental section;

[0062] S4, calculated potential values ​​at both ends of the 5-meter experimental interval;

[0063] S5, adjusting the DC adjustable power supply 3 and the adjustable resistor 2 so that the reading of the voltage test component is equal to the potential value, that is, under this condition, the track bed simulation component 1 highly simulates the subway site environment;

[0064] S6 , reading the current value of the current testing component 4 .

[0065] In the above embodiment, after step S6, the following steps are also included:

[0066] S7. Change the connection position between the second end of the voltage test component and the trackbed simulation component 1, and obtain multiple voltage values ​​in sequence. Specifically, the voltmeter 5 is connected to different measuring terminals. On the same column of measuring terminals, assuming that the spacing between the measuring terminals is 1, the measured potentials are V1, V2, and V3 respectively. When the spacing between the measuring terminals is 21, the measured potentials are V4 and V5. When the spacing between the measuring terminals is 31, the measured potential is V6. Then the surface potential gradient grad in this direction can be expressed as:

[0067] grad1=(V1 / l+V2 / l+V3 / l) / 3

[0068] grad2=(V4 / 2l+V5 / 2l) / 2

[0069] grad3=V6 / 3l

[0070] grad=(grad1+grad2+grad3) / 3;

[0071] S8. Calculate the potential gradient according to V1 to V6 in step S7.

[0072] In order to test the subway stray current in an all-round way, in this embodiment, after step S8, the following steps are also included:

[0073] S91. Replace the spring bars 142, baffle seats 144 and rubber pads 141 with different resistivities in sequence, so that the resistivity of the entire ballast simulation component 1 changes, repeat steps S6 to S8, and calculate the current value and potential gradient when the resistivity of the insulating fastener changes.

[0074] Alternatively, in the above embodiment, after step S8, the following steps may also be included:

[0075] S92. Spray water onto the concrete layer 11 to change the humidity of the concrete layer 11 so that the resistivity of the entire roadbed simulation component 1 changes. Repeat steps S6 to S8 to calculate the current value and potential gradient when the resistivity of the insulating fastener changes.

[0076] 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 subway stray current testing system, characterized in that: include: Track bed simulation parts, used to simulate subway track bed; An adjustable resistor, a first end of which is connected to the ballast simulation component and is used to simulate the resistance value when the ballast length changes in an actual field environment; A DC adjustable power supply, a first end of which is connected to the second end of the adjustable resistor, for providing a test power supply; A current test component, a first end of which is connected to the second end of the DC adjustable power supply, and a second end of the current test component is connected to the ballast bed simulation component, for measuring the current value flowing through the ballast bed simulation component; A voltage testing component, a first end of which is connected to the second end of the current testing component, and a second end of which is connected to the first end of the adjustable resistor, is used to measure the voltage value at both ends of the track bed simulation component.

2. The subway stray current testing system according to claim 1, characterized in that: The ballast bed simulation component includes: a concrete layer, a rail group, a drainage net and an insulating fastener device; The drainage net is arranged in the concrete layer, and the rail set is fixed above the concrete layer by the insulating fastener device.

3. The subway stray current testing system according to claim 2, characterized in that: The current testing assembly includes: a first ammeter, the rail group includes a first rail and a second rail, the first end of the adjustable resistor is connected to the first end of the first rail and the first end of the second rail, the first end of the first ammeter is connected to the second end of the DC adjustable power supply, and the second end of the first ammeter is connected to the second end of the first rail and the second end of the second rail.

4. The subway stray current testing system according to claim 2, characterized in that: The current testing assembly includes: a second ammeter, the drainage network is provided with a busbar extending to the outside of the concrete layer, the first end of the second ammeter is connected to the second end of the DC adjustable power supply, and the second end of the second ammeter is connected to the busbar.

5. The subway stray current testing system according to claim 2, characterized in that: The current testing assembly includes: a third ammeter, the concrete layer is provided with a current measuring terminal extending outward, the first end of the third ammeter is connected to the second end of the DC adjustable power supply, and the second end of the third ammeter is connected to one of the measuring terminals.

6. The subway stray current testing system according to claim 3, characterized in that: The voltage testing component is a voltmeter, and a plurality of voltage testing terminals are also provided on the concrete layer; The first end of the voltmeter is connected to the second end of the first ammeter, and the second end of the voltmeter is connected to the first end of the adjustable resistor; or the first end of the voltmeter is connected to the second end of the first ammeter, and the second end of the voltmeter is connected to the voltage test terminal; The first steel rail and the second steel rail are both 60 gauge.

7. A subway stray current testing method, characterized in that: The test system according to any one of claims 1 to 6, wherein the test method comprises the following steps: S1. Key parameters of test trackbed simulation parts; S2. Calculate the potential distribution law of the subway rails according to the key parameters; S3, selecting a first length of the actual roadbed at the subway site as the experimental interval; S4, calculating the potential values ​​at both ends of the experimental interval; S5, adjusting the DC adjustable power supply and the adjustable resistor so that the reading of the voltage test component is equal to the potential value; S6. Read the current value of the current testing component.

8. The subway stray current testing method according to claim 7, characterized in that: After step S6, the following steps are also included: S7, changing the connection position between the second end of the voltage testing component and the track bed simulation component, and sequentially acquiring a plurality of the voltage values; S8. Calculate the potential gradient according to the multiple voltage values.

9. The subway stray current testing method according to claim 8, characterized in that: The track bed simulation component is provided with a plurality of spring bars, baffle seats, and rubber pads. After step S8, the following steps are also included: S91, replace the elastic bars, the baffle seats, and the rubber pads with different resistivities in sequence, repeat steps S6 to S8, and calculate the current value and potential gradient when the resistivity of the insulating fastener changes.

10. The subway stray current testing method according to claim 8, characterized in that: The roadbed simulation part has a concrete layer, and after step S8, the following steps are also included: S92, spraying water onto the concrete layer to change the humidity of the concrete layer, repeating steps S6 to S8, and calculating the current value and potential gradient when the resistivity of the insulating fastener changes.

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