A Coordinate Processing Method for the Integrated Modeling of Rail Transit and Urban Power Grid Substations

Abstract

The present invention discloses a coordinate processing method for the integrated modeling of rail transit and urban power grid substations, including: obtaining a first position parameter and a second position parameter, where the first position parameter is used to represent the information of subway stations in urban rail transit, and the second position parameter is used to represent the information of substations in the urban power grid; constructing a model coordinate system, and determining the coordinate information of the subway station in the model coordinate system according to the first position parameter; determining the coordinate information of the substation in the model coordinate system according to the second position parameter, and completing the coordinate processing for the integrated modeling of rail transit and urban power grid substations. By establishing a model coordinate system for subway stations in urban rail transit and integrating the longitude and latitude of the substation into the model coordinate system, the present invention establishes a coordinate system including the coordinates of subway stations and substations, thereby being used to establish an integrated model of urban rail transit and urban power grid, facilitating the analysis of characteristics such as the distribution law and propagation characteristics of stray current in the power grid system.

Description

Technical Field

[0001] The present invention belongs to the field of data processing, and particularly relates to a coordinate processing method for the integrated modeling of rail transit and urban power grid substations. Background Technique

[0002] In a subway system with DC traction power supply, part of the current leaks from the rail to the ground, forming stray current. With the continuous development of the city, the scale of the subway system and the power grid system is getting larger and the connection is getting closer. More and more stray current invades the urban power grid through various channels, resulting in phenomena such as DC bias magnetization of transformers and corrosion of grounding grids. Long-term DC bias magnetization may cause situations such as loosening of fasteners and overheating of windings in transformers, seriously threatening the safe operation of main transformers.

[0003] Establishing an integrated model can explore the propagation law of stray current in the power grid to guide protection. However, there are few studies on establishing an integrated model of the subway and the power grid. Currently, most existing studies only establish a subway stray current calculation model or a distribution model of stray current in the power grid separately according to requirements. Compared with the integrated model, separate modeling cannot comprehensively reflect the circulation path and propagation characteristics of stray current invading the urban power grid, which is not convenient for research and analysis of the distribution law of stray current in the power grid. Therefore, the protection and treatment of stray current in the urban power grid are relatively blind and ineffective.

[0004] The CDEGS software can be used to establish an integrated model. However, the CDEGS software cannot directly input longitude and latitude. It is necessary to establish a coordinate system in the model and input coordinates based on this coordinate system. Currently, the commonly used format of substation location information is longitude and latitude, and it is necessary to convert the longitude and latitude of the substation and the model coordinates. At the same time, for the integrated modeling of rail transit and urban power grid, it is necessary to integrate the coordinates of the subway system and the power grid system. However, there is currently a lack of an effective method for integrating the coordinates of the subway model and the longitude and latitude of the power grid substation, and it is impossible to establish a good integrated model of stray current in urban rail transit and urban power grid. Summary of the Invention

[0005] The purpose of this application is to provide a coordinate processing method for the integrated modeling of rail transit and urban power grid substations, which solves the problem that when using the CDEGS software to establish an integrated model in the prior art, longitude and latitude cannot be input, resulting in the inability to establish a good integrated model of stray current in urban rail transit and urban power grid.

[0006] The present invention is realized through the following technical solutions:

[0007] A coordinate processing method for the integrated modeling of rail transit and urban power grid substations includes:

[0008] Obtain a first position parameter and a second position parameter, where the first position parameter is used to represent the information of subway stations of urban rail transit, and the second position parameter is used to represent the information of substations of the urban power grid;

[0009] Construct a model coordinate system, and determine the coordinate information of the subway station in the model coordinate system according to the first position parameter;

[0010] Determine the coordinate information of the substation in the model coordinate system according to the second position parameter, and complete the coordinate processing for the integrated modeling of rail transit and urban power grid substations.

[0011] In a possible implementation manner, the first position parameter includes the lines of urban rail transit, the subway stations on each line, and the geographical location information of the subway stations on each line.

[0012] In a possible implementation manner, the geographical location information of the subway stations on each line includes: the distance and direction between every two adjacent subway stations on the line.

[0013] In a possible implementation manner, the second position parameter includes the substations of the urban power grid and the longitude and latitude of the substations.

[0014] In a possible implementation manner, constructing a model coordinate system and determining the coordinate information of the subway station in the model coordinate system according to the first position parameter includes:

[0015] Construct a subway coordinate system corresponding to each line according to the subway stations on each line and the geographical location information of the subway stations;

[0016] Determine one subway coordinate system among the subway coordinate systems corresponding to all lines as the model coordinate system;

[0017] Determine the coordinate information of the subway stations in the model coordinate system according to the subway coordinate systems corresponding to all lines.

[0018] In a possible implementation manner, constructing a subway coordinate system corresponding to each line according to the subway stations on each line and the geographical location information of the subway stations includes:

[0019] Select the starting subway station on the i-th line as the coordinate origin of this line, and establish the coordinate system of this line with the due east as the positive direction of the horizontal axis and the due north as the positive direction of the vertical axis; i = 1, 2, …, I, where I represents the total number of lines in urban rail transit;

[0020] Determine the coordinates of all subway stations on the i-th line in sequence according to the distances and directions corresponding to the other subway stations on the i-th line except the starting subway station;

[0021] According to the above method, traverse all the lines in urban rail transit to obtain the subway coordinate system corresponding to each line.

[0022] In a possible implementation manner, according to the subway coordinate systems corresponding to all the lines, determine the coordinate information of subway stations in the model coordinate system, including:

[0023] Call a third-party map interface to determine the longitude and latitude of the coordinate origin in all the subway coordinate systems, and obtain the longitude and latitude of the coordinate origin in the subway coordinate system and the longitude and latitude of the coordinate origin in the model coordinate system;

[0024] According to the longitude and latitude of the coordinate origin in the subway coordinate system and the longitude and latitude of the coordinate origin in the model coordinate system, determine the distance and direction of the coordinate origin in the subway coordinate system relative to the coordinate origin in the model coordinate system;

[0025] According to the determined distance and direction, transform all the coordinate points in the subway coordinate system into the model coordinate system to obtain the coordinate information of the subway stations in the model coordinate system. <(

[0026] In a possible implementation manner, according to the determined distance and direction, transform all the coordinate points in the subway coordinate system into the model coordinate system to obtain the coordinate information of the subway stations in the model coordinate system, including:

[0027] Extract the coordinate origin in the subway coordinate system to obtain the coordinate points to be converted;

[0028] According to the determined direction, determine the orientation of the coordinate points to be converted in the model coordinate system;

[0029] According to the determined distance, determine the connection line between the coordinate points to be converted and the coordinate origin of the model coordinate system in the model coordinate system;

[0030] Map this connection line to the horizontal axis and vertical axis of the model coordinate system to obtain the coordinate information of the coordinate points to be converted in the model coordinate system;

[0031] According to the coordinate information of the coordinate points to be converted in the model coordinate system and the coordinate information of the coordinate points in the subway coordinate system, transform all the coordinate points in the subway coordinate system into the model coordinate system to obtain the coordinate information of the subway stations in the model coordinate system.

[0032] In a possible implementation manner, according to the coordinate information of the coordinate points to be converted in the model coordinate system and the coordinate information of the coordinate points in the subway coordinate system, transform all the coordinate points in the subway coordinate system into the model coordinate system, including:

[0033] " According to the coordinate information of the coordinate points to be converted in the model coordinate system, obtain the basic horizontal axis coordinates and the basic vertical axis coordinates;

[0034] According to the coordinate information of the coordinate points in the subway coordinate system, add the horizontal axis coordinate of the coordinate point in the subway coordinate system to the basic horizontal axis coordinate to obtain the horizontal axis coordinate of the coordinate point in the model coordinate system; add the vertical axis coordinate of the coordinate point in the subway coordinate system to the basic vertical axis coordinate to obtain the vertical axis coordinate of the coordinate point in the model coordinate system;

[0035] Use the obtained horizontal axis coordinate and vertical axis coordinate as the coordinate information of the subway station in the model coordinate system.

[0036] In a possible implementation manner, determining the coordinate information of the substation in the model coordinate system according to the second position parameter includes:

[0037] According to the longitude and latitude of the coordinate origin in the model coordinate system and the longitude and latitude of the substation, determine the distance and direction between the substation and the coordinate origin in the model coordinate system;

[0038] According to the distance and direction between the substation and the coordinate origin in the model coordinate system, determine the coordinate information of the substation in the model coordinate system;

[0039] Traverse all substations to obtain the coordinate information of all substations in the model coordinate system, and complete the coordinate processing for the integrated modeling of rail transit and urban power grid substations.

[0040] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0041] The present invention provides a coordinate processing method for the integrated modeling of rail transit and urban power grid substations. By establishing a model coordinate system for subway stations in urban rail transit and integrating the longitude and latitude of substations into the model coordinate system, a coordinate system including the coordinates of subway stations and substations is established, so as to be used to establish an integrated model of urban rail transit and urban power grid, which facilitates the analysis of characteristics such as the distribution law and propagation characteristics of stray current in the power grid system, and further provides a basis for the prevention and treatment of DC bias of transformers and corrosion of urban power grid structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts. In the drawings:

[0043] Figure 1 It is a flowchart of a coordinate processing method for the integrated modeling of rail transit and urban power grid substations provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] To make the objectives, technical solutions, and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings. The illustrative embodiments and descriptions thereof of the present invention are only used to explain the present invention and do not limit the present invention.

[0045] Embodiment

[0046] As Figure 1 shown, a coordinate processing method for the integrated modeling of rail transit and urban power grid substations includes:

[0047] S1. Obtain a first position parameter and a second position parameter. The first position parameter is used to represent the information of subway stations of urban rail transit, and the second position parameter is used to represent the information of substations of the urban power grid.

[0048] The basic parameters of the subway system can be obtained according to the design and construction drawings of the subway system to obtain the first position parameter, and the first position parameter can be multiple traffic lines, stations on the lines, and the distance and direction between adjacent two stations. The basic parameters of the urban power grid can be obtained according to the design plan, operation data, and ledger information of the urban power grid to obtain the second position parameter, and the second position parameter can be the number of substations and the longitude and latitude of each substation.

[0049] S2. Construct a model coordinate system, and determine the coordinate information of subway stations in the model coordinate system according to the first position parameter.

[0050] The model coordinate system can be constructed in the following way: Arbitrarily select a line, use the starting point of the line as the coordinate origin, and determine the coordinate points of each station according to the stations on the line and the distance and direction between adjacent two stations to obtain the model coordinate system. For example, there is line A, its starting station is B, the second station is C, the unit length in the coordinate system is 1KM, the direction of C relative to B is 45° east of north, and the distance of C relative to B is Then take B as the origin of the coordinate system corresponding to line A, take the due east as the positive direction of the horizontal axis, and take the due north as the positive direction of the vertical axis. Then it can be determined that the direction of C in the coordinate system is 45° from the positive direction of the horizontal axis to the positive direction of the vertical axis, and the length of the line connecting C and the coordinate origin B is Thus, the coordinate of C is obtained as (1, 1).

[0051] After establishing the coordinate systems corresponding to all lines, the direction and distance between each starting station and the starting station corresponding to the model coordinate system can be determined, and then according to this direction and distance, the coordinate points in the coordinate systems corresponding to all lines are converted into the model coordinate system.

[0052] S3. Determine the coordinate information of the substation in the model coordinate system according to the second position parameter, and complete the coordinate processing for the integrated modeling of the rail transit and the urban power grid substation.

[0053] The coordinate processing method provided by this application refers to the urban rail transit and the urban power grid topology map, and establishes a general coordinate system applicable to the CDEGS software and based on the subway system. Furthermore, using the map software, determine the model coordinates of the stations according to the geographical locations of the subway stations. Based on the actual longitude and latitude of the substation, convert them into model coordinates using the map software, and then more accurately obtain the integrated coordinates of the urban rail transit and the urban power grid substation in the CDEGS software.

[0054] The coordinate processing method provided by this application facilitates unifying and determining the station coordinates of two different systems, namely the subway and the power grid, in the CDEGS for establishing the integrated model of the urban rail transit and the urban power grid, which is convenient for analyzing characteristics such as the distribution law and propagation characteristics of stray current in the power grid system, and further provides a basis for the prevention and treatment of DC bias of transformers and corrosion of the urban power grid structure.

[0055] In a possible implementation manner, the first position parameter includes the lines of the urban rail transit, the subway stations on each line, and the geographical location information of the subway stations on each line.

[0056] In a possible implementation manner, the geographical location information of the subway stations on each line includes: the distance and direction between every two adjacent subway stations on the line.

[0057] In a possible implementation manner, the second position parameter includes the substations of the urban power grid and the longitude and latitude of the substations.

[0058] In a possible implementation manner, construct a model coordinate system, and determine the coordinate information of the subway stations in the model coordinate system according to the first position parameter, including:

[0059] Construct a subway coordinate system corresponding to each line according to the subway stations on each line and the geographical location information of the subway stations.

[0060] Determine one of the subway coordinate systems corresponding to all lines as the model coordinate system.

[0061] Optionally, in response to a computer editing instruction or a pre-stored determination instruction, determine one of the subway coordinate systems as the model coordinate system, or randomly determine one of the subway coordinate systems as the model coordinate system.

[0062] Determine the coordinate information of the subway stations in the model coordinate system according to the subway coordinate systems corresponding to all lines.

[0063] Determining the coordinate information of a subway station in the model coordinate system includes: converting each coordinate point in the subway coordinate system into a coordinate point in the model coordinate system, and then obtaining the coordinate information of the subway station in the model coordinate system.

[0064] In a possible implementation manner, according to the subway stations on each line and the geographical location information of the subway stations, constructing the subway coordinate system corresponding to each line includes:

[0065] Selecting the starting subway station on the i-th line as the coordinate origin of this line, and taking the due east as the positive direction of the horizontal axis and the due north as the positive direction of the vertical axis to establish the coordinate system of this line; i = 1, 2, …, I, where I represents the total number of lines in urban rail transit.

[0066] According to the distances and directions corresponding to the other subway stations on the i-th line except the starting subway station, and in the order of the subway stations, successively determining the coordinates of all subway stations on this line.

[0067] According to the above method, traversing all lines in urban rail transit to obtain the subway coordinate system corresponding to each line.

[0068] For example, there is a line A, and there are stations B, C, D, and E on this line A. First, taking B as the origin, according to the distance and direction between B and C, determine the coordinate of C. Then, according to the direction and distance between C and D, the distance and direction between D and B can be determined (triangle theorem, not elaborated here), and then according to the distance and direction between D and B, determine the coordinate of D, and so on.

[0069] In a possible implementation manner, according to the subway coordinate systems corresponding to all lines, determining the coordinate information of a subway station in the model coordinate system includes:

[0070] Invoking a third-party map interface to determine the longitude and latitude of the coordinate origin in all subway coordinate systems, obtaining the longitude and latitude of the coordinate origin in the subway coordinate system and the longitude and latitude of the coordinate origin in the model coordinate system (i.e., the coordinate origin of the model in the CDEGS software).

[0071] According to the longitude and latitude of the coordinate origin in the subway coordinate system and the longitude and latitude of the coordinate origin in the model coordinate system, determining the distance and direction of the coordinate origin in the subway coordinate system relative to the coordinate origin in the model coordinate system, that is, through the longitude and latitude between two points, converting the actual distance and relative direction between the two points.

[0072] According to the determined distance and direction, transforming all coordinate points in the subway coordinate system into the model coordinate system to obtain the coordinate information of the subway station in the model coordinate system.

[0073] In a possible implementation manner, according to the determined distance and direction, all coordinate points in the subway coordinate system are transformed into the model coordinate system to obtain the coordinate information of the subway station in the model coordinate system, including:

[0074] Extract the coordinate origin in the subway coordinate system to obtain the coordinate points to be transformed.

[0075] According to the determined direction, determine the orientation of the coordinate points to be transformed in the model coordinate system.

[0076] According to the determined distance, determine the connection line between the coordinate points to be transformed and the coordinate origin of the model coordinate system in the model coordinate system.

[0077] Map this connection line to the horizontal axis and vertical axis of the model coordinate system to obtain the coordinate information of the coordinate points to be transformed in the model coordinate system.

[0078] According to the coordinate information of the coordinate points to be transformed in the model coordinate system and the coordinate information of the coordinate points in the subway coordinate system, all coordinate points in the subway coordinate system are transformed into the model coordinate system to obtain the coordinate information of the subway station in the model coordinate system.

[0079] Assume that the determined direction is that the coordinate points to be transformed are due west of the coordinate origin of the model coordinate system, then the coordinate points to be transformed are located on the negative half-axis of the horizontal axis in the model coordinate system. Assume that the determined distance is 1 KM, and the unit distance on the model coordinate system represents 1 KM, then the coordinate points to be transformed are located at the position with a scale of 1 on the negative half-axis of the horizontal axis in the model coordinate system, that is, the coordinate information of the coordinate points to be transformed after being transformed into the model coordinate system is (-1, 0).

[0080] In a possible implementation manner, according to the coordinate information of the coordinate points to be transformed in the model coordinate system and the coordinate information of the coordinate points in the subway coordinate system, all coordinate points in the subway coordinate system are transformed into the model coordinate system, including:

[0081] According to the coordinate information of the coordinate points to be transformed in the model coordinate system, obtain the basic horizontal axis coordinate and the basic vertical axis coordinate.

[0082] According to the coordinate information of the coordinate points in the subway coordinate system, add the horizontal axis coordinate of the coordinate points in the subway coordinate system to the basic horizontal axis coordinate to obtain the horizontal axis coordinate of the coordinate points in the model coordinate system; add the vertical axis coordinate of the coordinate points in the subway coordinate system to the basic vertical axis coordinate to obtain the vertical axis coordinate of the coordinate points in the model coordinate system.

[0083] Use the obtained horizontal axis coordinate and vertical axis coordinate as the coordinate information of the subway station in the model coordinate system.

[0084] In a possible implementation manner, according to the second position parameter, determine the coordinate information of the substation in the model coordinate system, including:

[0085] According to the longitude and latitude of the coordinate origin in the model coordinate system and the longitude and latitude of the substation, determine the distance and direction between the substation and the coordinate origin in the model coordinate system.

[0086] According to the distance and direction between the substation and the coordinate origin in the model coordinate system, determine the coordinate information of the substation in the model coordinate system. This process is similar to the process of determining the corresponding coordinate information in the above-mentioned subway coordinate system and will not be elaborated here.

[0087] Traverse all substations to obtain the coordinate information of all substations in the model coordinate system, and complete the coordinate processing for the integrated modeling of rail transit and urban power grid substations.

[0088] The present invention provides a method for coordinate processing in the integrated modeling of rail transit and urban power grid substations. By establishing a model coordinate system for subway stations in urban rail transit and integrating the longitude and latitude of the substation into the model coordinate system, a coordinate system including the coordinates of subway stations and substations is established, so as to be used for establishing an integrated model of urban rail transit and urban power grid, which facilitates the analysis of characteristics such as the distribution law and propagation characteristics of stray current in the power grid system, and further provides a basis for the prevention and control of DC bias of transformers and corrosion of urban power grid structures.

[0089] The above-mentioned specific implementation manners further elaborate the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above-mentioned are only the specific implementation manners of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A coordinate processing method for the integrated modeling of rail transit and urban power grid substations, characterized in that, Including: Obtain a first position parameter and a second position parameter, where the first position parameter is used to characterize the information of subway stations in urban rail transit, and the second position parameter is used to characterize the information of substations in the urban power grid; Construct a model coordinate system, and determine the coordinate information of subway stations in the model coordinate system according to the first position parameter; Determine the coordinate information of substations in the model coordinate system according to the second position parameter, and complete the coordinate processing for the integration modeling of rail transit and urban power grid substations; The first position parameter includes the lines of urban rail transit, the subway stations on each line, and the geographical location information of the subway stations on each line; The geographical location information of the subway stations on each line includes: the distance and direction between every two adjacent subway stations on the line; The second position parameter includes the substations of the urban power grid and the longitude and latitude of the substations; Construct a model coordinate system, and determine the coordinate information of subway stations in the model coordinate system according to the first position parameter, including: Construct a subway coordinate system corresponding to each line according to the subway stations on each line and the geographical location information of the subway stations; Determine one subway coordinate system among all the subway coordinate systems corresponding to the lines as the model coordinate system; Determine the coordinate information of subway stations in the model coordinate system according to all the subway coordinate systems corresponding to the lines; Construct a subway coordinate system corresponding to each line according to the subway stations on each line and the geographical location information of the subway stations, including: Select the starting subway station in the i-th line as the coordinate origin of this line, and establish the coordinate system of this line with the due east as the positive direction of the horizontal axis and the due north as the positive direction of the vertical axis; i = 1, 2, …, I, where I represents the total number of lines in urban rail transit; Determine the coordinates of all subway stations on this line in sequence according to the distances and directions corresponding to the other subway stations on the i-th line except the starting subway station; Traverse all lines in urban rail transit according to the above method to obtain the subway coordinate system corresponding to each line; Determine the coordinate information of subway stations in the model coordinate system according to all the subway coordinate systems corresponding to the lines, including: Call a third-party map interface to determine the longitude and latitude of the coordinate origin in all subway coordinate systems, and obtain the longitude and latitude of the coordinate origin in the subway coordinate system and the longitude and latitude of the coordinate origin in the model coordinate system; Determine the distance and direction of the coordinate origin in the subway coordinate system relative to the coordinate origin in the model coordinate system according to the longitude and latitude of the coordinate origin in the subway coordinate system and the longitude and latitude of the coordinate origin in the model coordinate system; Transform all coordinate points in the subway coordinate system to the model coordinate system according to the determined distance and direction to obtain the coordinate information of subway stations in the model coordinate system; Transform all coordinate points in the subway coordinate system to the model coordinate system according to the determined distance and direction to obtain the coordinate information of subway stations in the model coordinate system, including: Extract the coordinate origin in the subway coordinate system to obtain the coordinate points to be transformed; Determine the orientation of the coordinate points to be transformed in the model coordinate system according to the determined direction; Determine the connection line between the coordinate points to be transformed and the coordinate origin of the model coordinate system in the model coordinate system according to the determined distance; Map the connection line to the horizontal and vertical axes of the model coordinate system to obtain the coordinate information of the coordinate points to be converted in the model coordinate system; According to the coordinate information of the coordinate points to be converted in the model coordinate system and the coordinate information of the coordinate points in the subway coordinate system, transform all the coordinate points in the subway coordinate system into the model coordinate system to obtain the coordinate information of the subway stations in the model coordinate system; According to the coordinate information of the coordinate points to be converted in the model coordinate system and the coordinate information of the coordinate points in the subway coordinate system, transform all the coordinate points in the subway coordinate system into the model coordinate system, including: According to the coordinate information of the coordinate points to be converted in the model coordinate system, obtain the basic horizontal axis coordinate and the basic vertical axis coordinate; According to the coordinate information of the coordinate points in the subway coordinate system, add the horizontal axis coordinate of the coordinate points in the subway coordinate system to the basic horizontal axis coordinate to obtain the horizontal axis coordinate of the coordinate points in the model coordinate system; add the vertical axis coordinate of the coordinate points in the subway coordinate system to the basic vertical axis coordinate to obtain the vertical axis coordinate of the coordinate points in the model coordinate system; Use the obtained horizontal axis coordinate and vertical axis coordinate as the coordinate information of the subway stations in the model coordinate system.

2. The coordinate processing method for integrated modeling of rail transit and urban power grid substation according to claim 1, wherein According to the second position parameter, determine the coordinate information of the substation in the model coordinate system, including: According to the longitude and latitude of the coordinate origin in the model coordinate system and the longitude and latitude of the substation, determine the distance and direction between the substation and the coordinate origin in the model coordinate system; According to the distance and direction between the substation and the coordinate origin in the model coordinate system, determine the coordinate information of the substation in the model coordinate system; Traverse all substations to obtain the coordinate information of all substations in the model coordinate system, and complete the coordinate processing of the integration modeling of rail transit and urban power grid substations.

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