Method, device and equipment for calculating cable armor layer stray current and storage medium

Abstract

The application relates to a cable armor layer stray current calculation method and device, computer equipment and a storage medium. The method comprises the following steps: obtaining metro line power parameters and power grid line power parameters; constructing a metro leakage current distribution model according to the metro line power parameters; constructing a cable armor layer stray current distribution model according to the power grid line power parameters; simulating the leakage current distribution of the metro according to the metro leakage current distribution model, and determining the stray current of the cable armor layer under the leakage current distribution according to the cable armor layer stray current distribution model. The above method constructs a simulation model according to the topological structure and power parameters of the actual urban rail transit and urban power grid, simulates the longitudinal current of the cable armor layer based on the accurate conductor distribution, accurately reflects the current flow direction and current distribution in each part of the cable armor layer of the power grid, and the parameters used can be obtained through measurement and calculation in the actual project, and the method is more convenient and effective compared with the analytic method.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of urban rail transit, and in particular to a cable armor layer stray current calculation method and device, computer equipment and a storage medium. BACKGROUND

[0002] In the current rail transit system, the contact network transmits the power output from the positive side of the traction substation to the power transmission system of the locomotive through the pantograph, and then the power flows back to the negative side of the traction substation through the steel rail. However, due to the resistance of the steel rail itself and the fact that the steel rail and the ground cannot be completely insulated, part of the current leaks from the steel rail to the ground, forming stray current. The stray current can flow into the transformer neutral point, buried metal pipelines and urban power grid grounding cable armor layer through the ground, and then spread into the urban power grid from the above-mentioned positions, causing transformer DC bias and pipeline cable fire, which greatly affects the safe operation of the power grid.

[0003] With the development of urban rail transit and urban power grid modeling technology, the traditional solution is to calculate the stray current of the subway system using analytical method to obtain the distribution of the stray current on the subway side. However, the research mainly focuses on geomagnetic storms or high-voltage direct current transmission, and there is currently no effective means for calculating the stray current distribution in the cable armor layer of the urban power grid. SUMMARY

[0004] Therefore, it is necessary to provide a cable armor layer stray current calculation method, device, computer equipment and computer readable storage medium capable of effectively calculating the stray current in the cable armor layer.

[0005] In a first aspect, the present application provides a cable armor layer stray current calculation method. The method comprises:

[0006] obtaining metro line power parameters and power grid line power parameters;

[0007] constructing a metro leakage current distribution model according to the metro line power parameters;

[0008] constructing a cable armor layer stray current distribution model according to the power grid line power parameters;

[0009] According to the metro leakage current distribution model, the leakage current distribution of the metro is simulated, and the stray current of the cable armor layer under the leakage current distribution is determined according to the cable armor layer stray current distribution model.

[0010] In one embodiment, the metro line power parameters include traction power supply system parameters, line parameters, stray current corrosion protection system parameters and soil resistivity.

[0011] In one of the embodiments, the traction power supply system parameters include contact line parameters, locomotive system parameters and traction substation parameters; the line parameters include urban rail transit line length, line number, rail cross-sectional area, rail unit length resistance and rail to ground transition resistance; the stray current corrosion protection system parameters include drainage system parameters and grounding system parameters.

[0012] In one of the embodiments, the constructing a subway leakage current distribution model according to the subway line power parameters includes:

[0013] constructing a soil medium layer according to the soil resistivity;

[0014] constructing a contact line, a rail, a drainage network, a grounding system and a traction substation of the subway in the soil medium layer to form a subway leakage current distribution model; wherein the contact line is determined by the urban rail transit line length and the contact line parameters, the rail is determined by the rail cross-sectional area, the rail unit length resistance and the rail to ground transition resistance, the drainage network is determined by the drainage system parameters, the grounding system is determined by the grounding system parameters, and the traction substation is determined by the traction substation parameters.

[0015] In one of the embodiments, the simulating a leakage current distribution of the subway according to the subway leakage current distribution model includes:

[0016] simulating a leakage current distribution of the subway according to the locomotive system parameters injecting current excitation in the contact line and the rail.

[0017] In one of the embodiments, the power grid line power parameters include transformer system parameters and transmission system parameters, the transformer system parameters include power grid substation location, substation level and transformer each winding DC equivalent resistance, and the transmission system parameters include transmission line type and length, line number, transmission conductor radius and transmission conductor resistivity; wherein the transmission line type includes overhead transmission line and cable transmission line.

[0018] In one of the embodiments, the constructing a cable armor layer stray current distribution model according to the power grid line power parameters includes:

[0019] The substation grounding grid and the transformer grounding line, the cable armor grounding line and the overhead grounding line connected with the substation grounding grid are constructed in the soil medium layer to form a cable armor layer stray current distribution model; wherein the substation grounding grid is determined by the power grid substation position, the substation level and the direct current equivalent resistance of each winding of the transformer, and the transformer grounding line, the cable armor grounding line and the overhead grounding line are determined by the power transmission line type and length, the line number, the radius of the power transmission conductor and the resistivity of the power transmission conductor.

[0020] In a second aspect, the present application also provides a cable armor layer stray current calculation device. The device comprises:

[0021] An acquisition module is configured to acquire metro line power parameters and power grid line power parameters;

[0022] A construction module is configured to construct a metro leakage current simulation model according to the metro line power parameters and construct a cable armor layer stray current simulation model according to the power grid line power parameters;

[0023] A simulation module is configured to simulate a metro leakage current distribution according to the metro leakage current distribution model and determine the stray current of the cable armor layer under the leakage current distribution according to the cable armor layer stray current distribution model.

[0024] In a third aspect, the present application also provides a computer device. The computer device comprises a memory and a processor, the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0025] In a fourth aspect, the present application also provides a computer readable storage medium. The computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the above method.

[0026] The above cable armor layer stray current calculation method, device, computer device and computer readable storage medium construct a simulation model according to the topological structure and power parameters of the actual urban rail transit and urban power grid, simulate the longitudinal current of the cable armor layer based on the accurate conductor distribution, accurately reflect the current flow direction and current distribution in each part of the cable armor layer of the power grid, and the parameters used can be obtained by measurement and calculation in the actual project. Compared with the analytical method, the method is more convenient and effective, and provides a basis for solving the transformer direct current magnetic bias, the prevention and treatment of urban power grid structure corrosion. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is an application environment diagram of the cable armor layer stray current calculation method in one embodiment;

[0028] Figure 2 A flowchart of a method for calculating the cable armor layer stray current in an embodiment;

[0029] Figure 3 A flowchart of a step of simulating the subway leakage current distribution in an embodiment;

[0030] Figure 4 A block diagram of a structure of a cable armor layer stray current calculation device in an embodiment;

[0031] Figure 5 An internal structure diagram of a computer device in an embodiment. DETAILED DESCRIPTION

[0032] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0033] The cable armor layer stray current calculation method provided by the embodiments of the present application can be applied in the application environment as shown in Figure 1 . The terminal 102 communicates with the server 104 through the network. The data storage system can store the data required to be processed by the server 104. The data storage system can be integrated on the server 104, or placed on the cloud or other network servers. Specifically, the terminal 102 can obtain the subway line power parameters and the power grid line power parameters. The server 104 constructs a subway leakage current distribution model according to the subway line power parameters obtained by the terminal 102, and constructs a cable armor layer stray current distribution model according to the power grid line power parameters. Finally, the server 104 simulates the leakage current distribution of the subway according to the subway leakage current distribution model, and determines the stray current of the cable armor layer under the leakage current distribution according to the cable armor layer stray current distribution model. The terminal 102 can be, but is not limited to, various personal computers, notebook computers, smart phones, tablet computers, Internet of Things devices and portable wearable devices. The Internet of Things device can be a smart speaker, a smart television, a smart air conditioner, a smart vehicle device, etc. The portable wearable device can be a smart watch, a smart bracelet, a head-mounted device, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers.

[0034] In an embodiment, as shown in Figure 2 , a cable armor layer stray current calculation method is provided. Taking the server 104 in Figure 1 as an example, the method includes the following steps:

[0035] Step 202: Obtain metro line power parameters and power grid line power parameters.

[0036] The metro line power parameters represent the line structure and power parameters in the running process of the metro rail transit system. The above metro line power parameters can be used to simulate and calculate the leakage current distribution in the metro rail transit system more accurately. Specifically, the data in the above metro line power parameters can be obtained in various ways. Some of the structural parameters of the metro line can be obtained from the design and construction drawings of the metro system. In addition, the data related to the power parameters of the metro running can be obtained by the acquisition device during the metro running test.

[0037] In addition, the power grid line power parameters represent the related parameters of the power transmission system and the grounding system of the urban power grid. The metro rail transit system and the urban power grid are not only directly connected through the power transmission line of the power transmission system, but also indirectly connected through the land and the grounding system on both sides. Using the above power grid line power parameters and the simulated leakage current distribution in the metro rail transit system, the stray current in the cable armor layer of the urban power grid can be obtained. Specifically, the data in the above power grid line power parameters can also be obtained in various ways according to the specific source of the data, such as the design planning, operation data, and account information of the urban power grid.

[0038] Step 204: Construct a metro leakage current distribution model according to the metro line power parameters.

[0039] Specifically, first, the soil medium layer is constructed according to the soil resistivity. Then, the contact line, steel rail, drainage network, grounding system, and traction substation of the metro are constructed in the soil medium layer to form a metro leakage current distribution model; wherein the contact line is determined by the length of the urban rail transit line and the contact line parameters, the steel rail is determined by the steel rail cross-sectional area, the steel rail unit length resistance, and the steel rail to ground transition resistance, the drainage network is determined by the drainage system parameters, the grounding system is determined by the grounding system parameters, and the traction substation is determined by the traction substation parameters.

[0040] Step 206: Construct a cable armor layer stray current distribution model according to the power grid line power parameters.

[0041] Specifically, the transformer grounding wire, cable armor grounding wire, and overhead grounding wire connected to the transformer grounding wire of the substation grounding network are constructed in the above soil medium layer to form a cable armor layer stray current distribution model; wherein the substation grounding network is determined by the location of the power grid substation, the grade of the substation, and the direct current equivalent resistance of each winding of the transformer, and the transformer grounding wire, cable armor grounding wire, and overhead grounding wire are determined by the type and length of the power transmission line, the number of lines, the radius of the power transmission conductor, and the resistivity of the power transmission conductor.

[0042] Step 208: According to the subway leakage current distribution model, the leakage current distribution of the subway is simulated, and the stray current of the cable armor layer under the leakage current distribution is determined according to the cable armor layer stray current distribution model.

[0043] First, the leakage current distribution of the subway is simulated according to the current excitation injected into the contact line and the rail according to the locomotive system parameters. Specifically, according to the position of each locomotive, the current excitation A is injected into the corresponding position of each contact line equivalent conductor; at the same time, the current excitation B opposite to the direction of the current excitation A is injected into the corresponding position of each rail equivalent conductor. The amplitudes of the current excitation A and the current excitation B are the locomotive traction current in the obtained locomotive system parameters. Further, the resistance conductor network in the above-mentioned constructed subway leakage current distribution model is affected by the injected traction current, and the leakage current distribution of the subway is simulated.

[0044] Then, since the subway leakage current distribution model and the cable armor layer stray current distribution model are constructed in the same soil medium layer, the leakage current of the subway will flow into the cable armor layer conductor connected to the equivalent grid of the grounding grid of the transformer substation, forming a stray current. Therefore, after the leakage current distribution of the subway is simulated by using the injected traction current to affect the resistance conductor network in the above-mentioned constructed subway leakage current distribution model, the stray current of the cable armor layer under the leakage current distribution can be determined by detecting or calculating the current in the cable armor layer.

[0045] The method of obtaining the stray current in the cable armor layer is not unique. It can be obtained by measuring the current in the cable armor layer using a stray current detection module; or by analyzing the flow path of the stray current flowing into the grounding grid after passing through the cable armor layer, writing KVL (Kirchhoff Voltage Law) equations for each current loop, and then solving. It can be understood that the method of obtaining the stray current in the cable armor layer can also be other methods recognized by those skilled in the art based on the above-constructed subway leakage current distribution model and cable armor layer stray current distribution model, and this embodiment will not be described in detail.

[0046] In the above cable armor layer stray current calculation method, a simulation model is built according to the topological structure and power parameters of the actual urban rail transit and urban power grid, based on accurate conductor distribution, the longitudinal current of the cable armor layer is simulated, the current flow direction and current distribution in each part of the cable armor layer of the power grid are accurately reflected, and the parameters used can be obtained by measurement and calculation in actual engineering, which is more convenient and effective than the analytical method.

[0047] In one embodiment, the metro line power parameters include traction power supply system parameters, line parameters, stray current corrosion protection system parameters, and soil resistivity.

[0048] In one embodiment, the metro line power parameters include traction power supply system parameters, line parameters, stray current corrosion protection system parameters, and soil resistivity.

[0049] In one embodiment, the metro line power parameters include traction power supply system parameters, line parameters, stray current corrosion protection system parameters, and soil resistivity.

[0050] In one embodiment, the metro line power parameters include traction power supply system parameters, line parameters, stray current corrosion protection system parameters, and soil resistivity.

[0051] In one embodiment, the metro line power parameters include traction power supply system parameters, line parameters, stray current corrosion protection system parameters, and soil resistivity.

[0052] In one embodiment, the metro line power parameters include traction power supply system parameters, line parameters, stray current corrosion protection system parameters, and soil resistivity.

[0053] In one embodiment, such as Figure 3 As shown, step 204, which involves constructing a subway leakage current distribution model based on the subway line's electrical parameters, includes:

[0054] Step 302: Construct a soil medium layer based on the soil resistivity.

[0055] Specifically, since the ground between the rails and the city's grounding system is considered a uniform conductor, the soil is set as uniform soil when constructing the soil medium layer. Its parameters include soil resistivity, which can be taken as 200 Ω·m, the standard soil resistivity for loess in a dry environment, without limitation. Furthermore, the thickness of the soil medium layer is not limited, as long as it ensures the connection between the rails and the city's grounding system.

[0056] Step 304: Construct the subway's contact wire, rails, drainage network, grounding system, and traction substation in the soil medium layer to form a subway leakage current distribution model; wherein, the contact wire is determined by the length of the urban rail transit line and the contact wire parameters, the rail is determined by the rail cross-sectional area, the rail resistance per unit length, and the rail-to-ground transition resistance, the drainage network is determined by the drainage system parameters, the grounding system is determined by the grounding system parameters, and the traction substation is determined by the traction substation parameters.

[0057] Specifically, in the soil medium layer, a multi-layer resistive conductor network model is established according to the actual location sequence in the subway rail transit system, including the contact wire, rail, drainage network, grounding system and traction substation, to form a subway leakage current distribution model.

[0058] First, from the upper surface of the soil medium layer downwards a n Construct n L at meter location n Parallel circular conductors of steel rails, equivalent to the rails of a subway rail transit system. Specifically, n is the number of urban rail transit lines; L n The length of the nth urban rail transit line can be determined based on the actual line conditions; a n Let a be the depth of the rail of the nth urban rail transit line. n The value range of is not fixed and can be set between n and n-1. Furthermore, to avoid contact between different lines, the rail depth of each urban rail transit line is set at equal intervals, with an interval of 1 meter, i.e., a. n With a n-1 The spacing between them is 1 meter. Furthermore, resistance parameters are constructed for the equivalent conductors of each rail, with the longitudinal resistance per unit length being... , radius is A 0.01-meter-thick outer layer with a resistivity of [missing information] is constructed on the outer layer of the equivalent conductor of each rail. The coating. This assumes the locomotive is running at the center of the rails. It is half the resistance per unit length of the rail; It is obtained from the cross-sectional area of ​​the rail; R is the rail-to-ground transition resistance.

[0059] Then, downwards from the upper surface of the soil medium layer a n +b meters and a n Construct n L lines at a distance of -b meters. n A circular conductor, parallel to the equivalent conductor of the rail, represents the up and down contact wires of the equivalent subway rail transit system. Specifically, 'b' represents the interval between the rail and the contact wire, which can be set according to the actual situation. Additionally, resistance parameters need to be established for each contact wire's equivalent conductor. A fully insulating coating with an insulation coefficient needs to be constructed on the outer layer of each contact wire's equivalent conductor, and the resistance per unit length of each contact wire's equivalent conductor should be set according to the resistance per unit length of the contact wire.

[0060] Then, downwards from the upper surface of the soil medium layer a n Construct n L at +c meters. n A circular conductor, parallel to the equivalent conductor of the rail, represents the drainage network of an equivalent subway rail transit system. Specifically, c is the interval between the rail and the drainage network, which can be set according to actual conditions; the radius of each drainage network's equivalent conductor is r. c Rice, and r c =n p r p n p With r p These represent the number and radius of the actual drainage networks. Furthermore, resistance parameters are constructed for the equivalent conductors of each drainage network, setting the resistance per unit length of the equivalent conductor of each drainage network to... And R c =R SCCS / n p , where R SCCS The longitudinal resistance per unit length of the drainage network.

[0061] Next, downwards from the upper surface of the soil medium layer a n Construct n L at +d meters. n A circular conductor, parallel to the equivalent conductor of the rail, represents the grounding system of the equivalent subway rail transit system. Specifically, d is the interval between the rail and the grounding system, which can be set according to the actual situation; the radius of the equivalent conductor of each grounding system is r. d Rice, and r d =n j r j n j With r j These represent the number and radius of conductors in the actual grounding system. Furthermore, resistance parameters are constructed for the equivalent conductors of each grounding system, setting the resistance per unit length of the equivalent conductor in each drainage network to... , and R d = R j / n p , wherein R j is the longitudinal unit length resistance of the grounding system.

[0062] The following is explained and described by taking the open cut method subway structure as an example, taking the depth a1 of the first rail as 0.2 meters, taking the interval b between the rail and the catenary as 0.15 meters, taking the interval c between the rail and the drainage net as 0.3 meters, taking the interval d between the rail and the grounding system as 0.5 meters, and constructing a subway leakage current distribution model. A first equivalent rail is constructed at a depth of 0.2 meters below the upper surface of the soil medium layer, a first pair of upper and lower running contact wires parallel to the first equivalent rail are constructed at depths of 0.05 meters and 0.35 meters, a first equivalent drainage net parallel to the first equivalent rail is constructed at a depth of 0.5 meters, and a first equivalent grounding system parallel to the first equivalent rail is constructed at a depth of 0.7 meters. It can be understood that the depth a2 of the second rail is 1.2 meters, and the equivalent conductors of other subway leakage current distribution models are sequentially similar and are not described herein.

[0063] Further, according to the traction substation location and the equivalent resistance value of the traction substation in the traction substation parameters, two circular conductors with a length of e are constructed, which are equivalent to the positive and negative output ends of the traction substation. It can be understood that the positive traction substation equivalent conductor is connected to each contact wire equivalent conductor, and the negative traction substation equivalent conductor is connected to each rail equivalent conductor, which is equivalent to the power supply loop of the subway rail transit system. Specifically, e is the conductor length of the traction substation, which can be set according to the actual situation, for example, it can be set to 0.15 meters. In addition, resistance parameters also need to be constructed for the two traction substation equivalent conductors, an insulating coating with a complete insulation coefficient is constructed on the outer layer of the two traction substation equivalent conductors, and the unit length resistance of the two traction substation equivalent conductors is set to R q , and R q = 2R s / 0.15, wherein R s is the equivalent resistance value of the traction substation obtained.

[0064] In one embodiment, the leakage current distribution of the subway obtained in step 208 according to the subway leakage current distribution model includes: simulating the leakage current distribution of the subway according to the current injection excitation of the contact wire and the rail in the locomotive system parameters.

[0065] Wherein, according to the locomotive system parameters, it is assumed that there are y locomotives running on each urban rail transit line, and each locomotive corresponds to a required traction current. Specifically, according to the position of each locomotive, the current excitation A is injected into the equivalent conductor of each contact line corresponding to the position; at the same time, the current excitation B opposite to the direction of the current excitation A is injected into the equivalent conductor of each rail corresponding to the position. Wherein, the amplitude of the current excitation A and the current excitation B is the locomotive traction current in the obtained locomotive system parameters.

[0066] Further, the injected traction current acts on the resistance conductor network in the above-mentioned constructed subway leakage current distribution model to simulate the leakage current distribution of the subway. Wherein, the method of obtaining the leakage current distribution of the subway is not unique, which can be obtained by detecting each part of the resistance conductor network using the leakage current detection module and then combining it; or it can be directly constructed as a distribution function with track position, injected traction current as independent variable, and leakage current fitting value as dependent variable, that is, the calculation formula of the leakage current at the current time can be obtained, and the traction current at different positions is substituted into the distribution function, and the leakage current distribution of the subway can be simulated. It can be understood that the method of obtaining the leakage current distribution of the subway can also be other ways recognized by those skilled in the art based on the above-mentioned constructed subway leakage current distribution model, and this embodiment will not be repeated.

[0067] In one embodiment, the power grid line power parameters include power transformation system parameters and power transmission system parameters, the power transformation system parameters include power grid substation position, substation level and DC equivalent resistance of each winding of the transformer, and the power transmission system parameters include power transmission line type and length, line number, radius of power transmission conductor and resistivity of power transmission conductor; wherein, the power transmission line type includes overhead power transmission line and cable power transmission line.

[0068] Specifically, the urban power grid supplies power for the subway rail transit system and other urban power equipment. The urban power grid can be understood as including two parts of power transformation system and power transmission system, the power transformation system is to boost or step down the voltage to a suitable amplitude through the transformer and other equipment in the substation, and then the power transmission system is to transmit the boosted or stepped down power to each power equipment through the power transmission line.

[0069] The power grid system parameters can include power grid substation locations, substation levels, and direct current equivalent resistances of each winding of a transformer. The substation levels can include 500 kV substations, 220 kV substations, and 110 kV substations, etc. The power transmission system parameters include power transmission line types and lengths, line numbers, radii of power transmission conductors, and resistivities of power transmission conductors. The power transmission line types include overhead power transmission lines and cable power transmission lines. For the overhead power transmission lines, the power transmission system parameters can include numbers of overhead ground wires, metal resistivities of the overhead ground wires, radii of the overhead ground wires, and cross-sectional areas of the overhead ground wires, etc. For the cable power transmission lines, the power transmission system parameters can include numbers of cables, metal resistivities of cable armor layers, radii of the cable armor layers, and thicknesses of the cable armor layers, etc.

[0070] Further, the urban power grid delivers the traction current required by the locomotive in the subway rail transit system to the traction substation through a cable. In addition, the leakage current in the subway rail transit system also flows into the grounding point of the transformer and the cable armor layer of the urban power grid through the ground.

[0071] In one embodiment, step 206 constructs a cable armor layer stray current distribution model according to the power grid line power parameters, including:

[0072] The transformer grounding wire, the cable armor grounding wire, and the overhead grounding wire connected to the substation grounding network are respectively constructed in the soil medium layer to form a cable armor layer stray current distribution model. The substation grounding network is determined by the power grid substation locations, the substation levels, and the direct current equivalent resistances of each winding of the transformer. The transformer grounding wire, the cable armor grounding wire, and the overhead grounding wire are determined by the power transmission line types and lengths, the line numbers, the radii of the power transmission conductors, and the resistivities of the power transmission conductors.

[0073] Specifically, in the same soil medium layer as the subway leakage current distribution model, a multi-layer resistance conductor network model is respectively established according to the actual position of the grounding network of the urban power grid, including the transformer and the grounding of the substation in the urban power grid, and the power transmission line connected to the transformer and the grounding network, to form a cable armor layer stray current distribution model.

[0074] First, a circular conductor vertically upward is constructed at a depth of f meters below the upper surface of the soil medium layer, which is equivalent to the grounding point of the transformer winding of the substation in the urban power grid. Specifically, f is the grounding point depth of the transformer winding, which can be set according to the actual situation, but needs to be guaranteed to be greater than the depth a of the steel rail of the nth urban rail transit line. n Further, for different substation levels, the resistance parameters of the transformer are set. For the 500 kV substation, the equivalent conductor length of the transformer winding grounding point of the substation is 2 meters, and the resistance of the equivalent conductor part at a depth of 14~13 meters is set to 0.0001 Ω / m. , the equivalent conductor part corresponding to the depth of 14~13 meters is set to have a resistance of , and are 1 / 3 of the equivalent resistance of the medium voltage DC and the high voltage DC of the 500 kV transformer, respectively. For the 220 kV transformer substation, the equivalent conductor length of the transformer winding of the substation is 1 meter, and the equivalent conductor part corresponding to the depth of 14~13 meters is set to have a resistance of , which is 1 / 3 of the equivalent resistance of the high voltage DC of the 220 kV transformer.

[0075] Then, the L meter conductor grid is constructed on the plane at the depth of f meters below the surface of the soil medium layer, which is equivalent to the grounding grid of the substation. Specifically, the equivalent conductor of the grounding point of the traction substation, the transformer winding and other electrical equipment connected to the lower right corner of the equivalent grid of the substation grounding grid. L is the length of each conductor in the grounding grid, which can be valued according to the actual situation and is different for different substation levels, for example, for the 500 kV substation, L is 300 meters; for the 220 kV substation, L is 200 meters; for the 110 kV substation, L is 100 meters. The L meter conductor grid can be constructed by vertically intersecting and equally spacing, and the grid spacing g is not fixed, which is set according to the actual equivalent resistance value, for example, the grid spacing g in this embodiment is 50 meters. The radius of the equivalent conductor in the grounding grid is 0.01 meters, and the resistance per unit length is , which is the obtained substation grounding resistance.

[0076] Then, the power transmission line conductor is constructed between the equivalent conductor of the transformer and the grounding point of the transformer winding placed on the surface of the soil medium layer for the 500 kV or 220 kV transformer, and the outer layer is constructed with a coating layer having a complete insulation coefficient. Specifically, the resistance of the equivalent conductor of the power transmission line is R L = ρ l L l / 3S l N l C, wherein ρ l is the obtained resistivity of the power transmission line, L l is the obtained length of the power transmission line, S l is the obtained cross-sectional area of a single power transmission line, N l is the obtained number of power transmission lines, and C is the number of power transmission line branches.

[0077] Finally, the grounding lines of each electrical equipment (including traction substation) placed on the surface of the soil medium layer are connected with the equivalent mesh of the substation grounding grid to build an overhead ground wire or a cable armor layer conductor, and a coating with a complete insulation coefficient is also built on the outer layer. Specifically, for the overhead ground wire equivalent conductor, the conductor resistance is R w = p w L w / S w N w , where p w is the obtained direct current resistivity of the overhead ground wire equivalent conductor, L w is the obtained length of the overhead ground wire, S w is the obtained cross-sectional area of a single overhead ground wire, and N w is the obtained number of overhead ground wire conductors. For the cable armor layer equivalent conductor, the conductor resistance is R c = p c L c / 2 p r c h c N c , where p c is the obtained metal resistivity of the cable armor layer, L c is the obtained length of the cable, r c is the obtained radius of the cable armor layer, h c is the obtained thickness of the cable armor layer, and N c is the obtained number of cables.

[0078] In one embodiment, to implement the technical solution of the present application, the soil module in the MALZ module of the CDEGS software and the SesCAD tool can be used to build the above-mentioned subway leakage current distribution model and the cable armor layer stray current distribution model.

[0079] Specifically, the soil medium layer can be built using the soil module, and the multi-layer resistance conductor network model of the contact line, the steel rail, the drainage network, the grounding system, and the traction substation in the leakage current distribution model, and the resistance conductor network model of the substation grounding grid and the transformer grounding line connecting the substation grounding grid, the cable armor grounding line, and the overhead grounding line in the cable armor layer stray current distribution model can be built using the SesCAD tool.

[0080] The CDEGS software can simulate the metal pipe with exposed and external insulation layer, closed pipeline, cable system and various complex soil structures, analyze and calculate the current distribution of the charged conductor at any position on the ground or underground and the conductor position distribution in the network topology structure composed of the conductor. Then the corresponding current excitation can be injected at any position on the conductor to obtain the current distribution in the constructed resistance conductor model. The specific process can be performed by a person skilled in the art according to the software related operation steps and the model structure data provided in the present application, and will not be described here.

[0081] It should be understood that, although each step in the flowchart involved in each embodiment as described above is displayed in sequence according to the arrow, these steps are not necessarily executed in the order indicated by the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other orders. Moreover, at least part of the steps in the flowchart involved in each embodiment as described above can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily sequential, but can be alternately or alternately executed with at least part of other steps or steps or stages in other steps.

[0082] Based on the same inventive concept, the present application also provides a cable armor layer stray current calculation device for implementing the above-mentioned cable armor layer stray current calculation method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more cable armor layer stray current calculation device embodiments provided below can refer to the limitations of the cable armor layer stray current calculation method in the above text, which will not be described here.

[0083] In one embodiment, as shown in FIG. 4, Figure 4 a cable armor layer stray current calculation device is provided, comprising an acquisition module 410, a construction module 420 and a simulation module 430, wherein:

[0084] The acquisition module 410 is configured to acquire metro line power parameters and power grid line power parameters.

[0085] The metro line power parameter represents the line structure of the metro rail transit system and the power parameter in the running process. The metro line power parameter can be used to simulate and calculate the leakage current distribution in the metro rail transit system more accurately. Specifically, the data in the metro line power parameter can be obtained in various ways. Some of the structural parameters of the metro line can be obtained from the design and construction drawings of the metro system. In addition, the data related to the power parameter of the metro running can be obtained by the acquisition device during the metro running test.

[0086] In addition, the power grid line power parameter represents the related parameters of the power transmission system and the grounding system of the urban power grid. The metro rail transit system and the urban power grid are not only directly connected through the power transmission line of the power transmission system, but also indirectly connected through the land and the grounding system on both sides. Using the power grid line power parameter and the simulated leakage current distribution in the metro rail transit system, the stray current in the cable armor layer of the urban power grid can be obtained. Specifically, the data in the power grid line power parameter can also be obtained in various ways according to the specific source of the data, such as the design planning, operation data and account information of the urban power grid.

[0087] The construction module 420 is configured to construct a metro leakage current simulation model according to the metro line power parameter, and construct a cable armor layer stray current simulation model according to the power grid line power parameter.

[0088] Specifically, first, the soil medium layer is constructed according to the soil resistivity. Then, the contact line, the rail, the drainage network, the grounding system and the traction substation of the metro are constructed in the soil medium layer respectively to form a metro leakage current distribution model; wherein the contact line is determined by the length of the urban rail transit line and the contact line parameter, the rail is determined by the rail cross-sectional area, the rail unit length resistance and the rail to ground transition resistance, the drainage network is determined by the drainage system parameter, the grounding system is determined by the grounding system parameter, and the traction substation is determined by the traction substation parameter.

[0089] Further, the transformer grounding line connected to the substation grounding net, the cable armor grounding line and the overhead grounding line are constructed in the soil medium layer to form a cable armor layer stray current distribution model; wherein the substation grounding net is determined by the power grid substation location, the substation level and the direct current equivalent resistance of each winding of the transformer, the transformer grounding line, the cable armor grounding line and the overhead grounding line are determined by the type and length of the power transmission line, the number of lines, the radius of the power transmission conductor and the resistivity of the power transmission conductor.

[0090] The simulation module 430 is configured to simulate the leakage current distribution of the metro according to the metro leakage current distribution model, and determine the stray current of the cable armor layer under the leakage current distribution according to the cable armor layer stray current distribution model.

[0091] Wherein, firstly, the metro leakage current distribution is simulated by injecting current excitation into the contact line and the steel rail according to the locomotive system parameters. Specifically, according to the position of each locomotive, the current excitation A is injected into the equivalent conductor of each contact line corresponding to the position; at the same time, the current excitation B opposite to the direction of the current excitation A is injected into the equivalent conductor of each steel rail corresponding to the position. Wherein, the amplitude of the current excitation A and the current excitation B is the locomotive traction current in the obtained locomotive system parameters. Further, the resistance conductor network in the above constructed metro leakage current distribution model is affected by the injected traction current, and the metro leakage current distribution is simulated.

[0092] Then, since the metro leakage current distribution model and the cable armor layer stray current distribution model are constructed in the same soil medium layer, the metro leakage current will flow into the cable armor layer conductor connected to the equivalent grid of the substation grounding grid, forming a stray current. Then, after the metro leakage current distribution is simulated by affecting the resistance conductor network in the above constructed metro leakage current distribution model by the injected traction current, the stray current of the cable armor layer under the leakage current distribution can be determined by detecting or calculating the current in the cable armor layer.

[0093] Wherein, the method of obtaining the stray current in the cable armor layer is not unique, which can be obtained by measuring the current in the cable armor layer by using the stray current detection module; or by analyzing the flow path of the stray current flowing into the grounding grid after passing through the cable armor layer, the KVL (Kirchhoff Voltage Law) equation of the current loop is written respectively, and then solved. It can be understood that the method of obtaining the stray current in the cable armor layer can also be other ways recognized by those skilled in the art based on the above constructed metro leakage current distribution model and the cable armor layer stray current distribution model, and this embodiment will not be repeated.

[0094] Each module in the above cable armor layer stray current calculation device can be realized by software, hardware and their combination. The above modules can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory in the computer device in software form, so as to call and execute the operation corresponding to each module by the processor.

[0095] In one embodiment, a computer device is provided, which can be a server, and the internal structure diagram thereof can be as shown in Figure 5As shown in the figure. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The database of the computer device is used to store data such as metro line power parameters and power grid line power parameters. The network interface of the computer device is used to communicate with external terminals through network connection. The computer program is executed by the processor to realize a cable armor layer stray current calculation method.

[0096] Those skilled in the art can understand that, Figure 5 The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0097] In one embodiment, a computer device is provided, comprising a memory and a processor, the memory storing a computer program, and the processor executing the computer program to realize the following steps:

[0098] Step 202: Obtain metro line power parameters and power grid line power parameters.

[0099] Step 204: Construct a metro leakage current distribution model according to the metro line power parameters.

[0100] Step 206: Construct a cable armor layer stray current distribution model according to the power grid line power parameters.

[0101] Step 208: According to the metro leakage current distribution model, the leakage current distribution of the metro is simulated, and the stray current of the cable armor layer under the leakage current distribution is determined according to the cable armor layer stray current distribution model.

[0102] In one embodiment, a computer readable storage medium is provided, which stores a computer program, and the computer program is executed by a processor to realize the following steps:

[0103] Step 202: Obtain metro line power parameters and power grid line power parameters.

[0104] Step 204: Construct a metro leakage current distribution model according to the metro line power parameters.

[0105] Step 206: Construct a cable armor layer stray current distribution model according to the power grid line power parameters.

[0106] Step 208: According to the subway leakage current distribution model, the leakage current distribution of the subway is simulated, and the cable armor layer is determined according to the cable armor layer leakage current distribution model. It should be noted that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties.

[0107] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. Any reference to memory, database or other medium used in the embodiments provided by the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided by the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without limitation. The processor involved in the embodiments provided by the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without limitation.

[0108] Any technical features in the above embodiments can be combined, and for the sake of brevity, not all possible combinations are described above, however, as long as the combinations of technical features do not have contradictions, they shall be considered within the scope of the present disclosure.

[0109] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it shall not be understood as a limitation on the patent scope of the present application. It shall be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these shall be within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A method of calculating the straying current of a cable armor layer, characterized by, The method comprises: acquiring metro line power parameters and power grid line power parameters, the power grid line power parameters comprising substation system parameters and transmission system parameters, wherein, for a cable transmission line, the transmission system parameters comprise cable quantity, cable armor layer metal resistivity, cable armor layer radius and cable armor layer thickness; in the same soil medium layer, constructing a metro leakage current distribution model according to the metro line power parameters and constructing a cable armor layer stray current distribution model according to the power grid line power parameters; simulating a metro leakage current distribution according to the metro leakage current distribution model; based on the cable armor layer stray current distribution model, analyzing a flow path of stray current flowing into a grounding grid after passing through the cable armor layer, respectively writing KVL equations for current loops in the flow path, and solving stray current of the cable armor layer under the leakage current distribution.

2. The method of claim 1, wherein, The metro line power parameters comprise traction power supply system parameters, line parameters, stray current corrosion protection system parameters and soil resistivity.

3. The method of claim 2, wherein, The traction power supply system parameters comprise contact line parameters, locomotive system parameters and traction substation parameters; the line parameters comprise urban rail transit line length, line quantity, steel rail cross-sectional area, steel rail unit length resistance and steel rail to ground transition resistance; the stray current corrosion protection system parameters comprise drainage system parameters and grounding system parameters.

4. The method of claim 3, wherein, The construction of the metro leakage current distribution model according to the metro line power parameters comprises: constructing a soil medium layer according to the soil resistivity; constructing a contact line, a steel rail, a drainage network, a grounding system and a traction substation of the metro in the soil medium layer to form a metro leakage current distribution model, wherein the contact line is determined by the urban rail transit line length and the contact line parameters, the steel rail is determined by the steel rail cross-sectional area, the steel rail unit length resistance and the steel rail to ground transition resistance, the drainage network is determined by the drainage system parameters, the grounding system is determined by the grounding system parameters, and the traction substation is determined by the traction substation parameters.

5. The method of claim 4, wherein, The simulation of the metro leakage current distribution according to the metro leakage current distribution model comprises: simulating a metro leakage current distribution according to current excitation of the contact line and the steel rail by the locomotive system parameters.

6. The method of claim 5, wherein, The substation system parameters comprise power grid substation position, substation grade and direct current equivalent resistance of each winding of a transformer, and the transmission system parameters comprise transmission line type and length, line quantity, radius of a transmission conductor and resistivity of the transmission conductor; for an overhead transmission line, the transmission system parameters comprise overhead ground wire quantity, overhead ground wire metal resistivity, overhead ground wire radius and overhead ground wire cross-sectional area.

7. The method of claim 6, wherein, The construction of the cable armor layer stray current distribution model according to the power grid line power parameters comprises: The substation grounding grid and the transformer grounding line, the cable armor grounding line and the overhead grounding line connected with the substation grounding grid are constructed in the soil medium layer respectively to form a cable armor layer stray current distribution model; wherein the substation grounding grid is determined by the power grid substation position, the substation level and the direct current equivalent resistance of each winding of the transformer, and the transformer grounding line, the cable armor grounding line and the overhead grounding line are determined by the power transmission line type and length, the line number, the radius of the power transmission conductor and the resistivity of the power transmission conductor.

8. A cable armor layer stray current calculation device characterized by comprising: The device comprises: An acquisition module is configured to acquire metro line power parameters and power grid line power parameters, wherein the power grid line power parameters comprise substation system parameters and power transmission system parameters, and the power transmission system parameters comprise the number of cables, the metal resistivity of the cable armor layer, the radius of the cable armor layer and the thickness of the cable armor layer. A construction module is configured to construct a metro leakage current simulation model according to the metro line power parameters and a cable armor layer stray current simulation model according to the power grid line power parameters in the same soil medium layer. An analog module is configured to simulate the leakage current distribution of the metro according to the metro leakage current distribution model, and to solve the stray current of the cable armor layer under the leakage current distribution by analyzing the flow path of the stray current flowing into the grounding grid after flowing through the cable armor layer, writing KVL equations for the current loop respectively, and based on the cable armor layer stray current distribution model. 9.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-8 when the computer program is executed by the processor. The processor executes the computer program to implement the steps of the method of any one of claims 1 to 7.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method of any one of claims 1 to 7.

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