Substation electrical secondary cable shortest laying path planning and length automatic statistics method

Abstract

The invention discloses a substation electrical secondary cable shortest laying path planning and length automatic statistical method, which comprises the following steps: drawing an electrical secondary cable laying path tree diagram on a substation layout diagram, extracting three-dimensional coordinates of key nodes of cable laying paths, and obtaining three-dimensional coordinates of intersection points of the cable laying paths; calculating the projection distance from the electrical equipment to each path line according to the extracted coordinate values, obtaining the nearest path line adjacent to the electrical equipment and the corresponding projection distance and projection three-dimensional coordinates, and obtaining the shortest laying path from the starting point equipment to the terminal point equipment; considering the design margin, the cable inlet and outlet channel position height difference and the shortest laying path from the starting point equipment to the terminal point equipment to obtain the actual laying length between the starting point equipment and the terminal point equipment; by designing the shortest laying path planning algorithm, the manual counting time and labor cost of the length of the electrical secondary cable of the transformer substation are greatly saved, human errors are reduced, the total length of cable laying is reduced, and the construction cost is saved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electrical secondary digitization, and particularly relates to a shortest laying path planning and length automatic statistics method for electrical secondary cables in a substation. BACKGROUND

[0002] Primary cables refer to power cables, i.e. cables for providing power supply for electrical equipment. Secondary cables refer to cables for control, signal transmission and feedback, such as motor operating column control cables, metering, protection and electrical communication cables, which all belong to secondary cables.

[0003] At present, the method for a traditional designer to statistically calculate the length of electrical secondary cables is to manually draw a connecting polyline from a starting point device to a terminal point device in a CAD plane layout, and then calculate the cable length in a cable list after considering a certain design margin. This method not only has a large workload, but also has a large error in the cable length calculated manually, which directly leads to a situation that the cable length in actual construction does not match the cable length for purchase. However, the electrical secondary cables have a long purchase time period, and the construction period is tight. Repeated purchase of cables not only delays the construction period, but also leads to waste of cable purchase.

[0004] Through investigation, there are few related researches on the shortest laying path planning and length automatic statistics of electrical secondary cables at home and abroad. SUMMARY

[0005] The present application aims at the deficiencies of the prior art, and provides a shortest laying path planning and length automatic statistics method for electrical secondary cables in a substation, which can accurately and quickly statistically calculate the purchase length of electrical secondary cables in the substation and design the shortest path for cable laying.

[0006] To achieve the above object, the technical scheme of the present application is as follows. A shortest laying path planning and length automatic statistics method for electrical secondary cables in a substation, which comprises the following steps: drawing a tree diagram of electrical secondary cable laying paths on a substation layout; respectively marking electrical primary devices, electrical secondary devices and cable inlet and outlet passages in the substation layout, and making the device marking names consistent with the device names in a list; extracting three-dimensional coordinates of key nodes of the cable laying paths, the key nodes being inflection points on the laying paths, and obtaining three-dimensional coordinates of intersection points of the cable laying paths; extracting three-dimensional coordinates of positions of the electrical primary devices, the electrical secondary devices and the cable inlet and outlet passages; matching starting point and terminal point device names in a list with device marking names in the substation layout, and assigning device types and device three-dimensional coordinates to the devices in the list; Calculate the projection distance of each electrical equipment to each path line, obtain the nearest path line of the electrical equipment and the corresponding projection distance and projection three-dimensional coordinates; According to the obtained nearest path line of the electrical equipment, and according to the three-dimensional coordinates of the intersection points of each laying path line, obtain the shortest laying path from the starting point equipment to the terminal equipment; Considering the design margin, the height difference of the cable inlet and outlet passage position, the projection distance of the electrical equipment to the adjacent path line, and the shortest laying path from the starting point equipment to the terminal equipment, obtain the actual laying length between the starting point equipment and the terminal equipment.

[0007] Further, the drawing of the electrical secondary cable laying path tree diagram on the substation layout includes: drawing n1 multi-segment lines from the starting point of the outdoor cable trench to the cable inlet position, and drawing n2 multi-segment lines from the cable trench outlet to the back of the electrical secondary equipment screen.

[0008] Further, the calculation of the projection distance of the electrical equipment to each path line, the obtaining of the nearest path line of the electrical equipment and the corresponding projection distance and projection three-dimensional coordinates includes: after calculating the projection distance of the electrical equipment to each segment of all path lines in CAD, recording the nearest distance value and the corresponding path line and the number of segments on the path line, and recording the three-dimensional coordinates of the projection point of the electrical equipment on the nearest path line.

[0009] Further, after calculating the projection distance of the electrical equipment to each path line in CAD, recording the nearest distance value and the corresponding path line includes: the cable laying path is divided into multiple segments by the inflection points on the laying path, when there are n inflection points on the cable laying path, the cable laying path is divided into n+1 segments; the projection distance of the electrical equipment to each segment of the cable laying path is divided into vertical projection distance and inclined projection distance, when the vertical projection point of the electrical equipment is located on the nth segment of the path line, the projection distance of the electrical equipment to the nth segment of the path line is the vertical projection distance of the electrical equipment to the nth segment; when the vertical projection point of the electrical equipment is not on the nth segment of the path line, the projection distance of the electrical equipment to the nth segment is the inclined projection distance of the electrical equipment to the nth segment, the inclined projection distance is the distance from the electrical equipment to the left end point or the right end point of the nth segment, and the inclined projection distance takes the smaller value of the distance from the electrical equipment to the left end point or the right end point of the nth segment; after calculating the projection distance of the electrical equipment to each segment of the cable laying path in CAD, record the nearest distance value and the position of the corresponding path segment, and record the three-dimensional coordinates of the projection point of the electrical equipment on the corresponding path segment.

[0010] Further, the shortest laying path planning from the starting point equipment to the terminal equipment includes: Construct the obtained three-dimensional intersection coordinates into a three-dimensional intersection coordinate matrix; Setting the cable laying path set from the starting device to the ending device as an empty set R; Judging whether the starting device and the ending device are on the same laying path line; if yes, inputting the laying path line into the cable laying path set, and the shortest cable laying path is the laying path line, ending, otherwise, obtaining the laying path lines intersecting with the ending device projection line segment as set A and obtaining the projection line segment corresponding to the starting device and the laying path lines intersecting with the projection line segment as set B according to the cable laying path intersection matrix; Obtaining all intersections existing between set B and set A, and obtaining the cable laying path where the intersection point is located according to the intersection, and placing the obtained cable laying path in set R; S76: calculating the cable laying length under the corresponding cable laying path according to the obtained cable laying path set, and obtaining the shortest length and the corresponding laying path.

[0011] Further, the setting of the cable laying path set from the starting device to the ending device as an empty set R comprises: determining the starting device and the ending device corresponding to the starting device according to the inventory device, and setting the coordinates of all inflection points between the starting device and the ending device, the cable inlet and outlet coordinates as an empty set R.

[0012] Further, the laying distance statistics between the starting device and the ending device comprises: Comparing the starting device and the ending device types; If the starting device and the ending device types are consistent, the actual cable laying length is , wherein is the device and laying path projection distance, is the device internal cable connection length, and is the calculated shortest laying path length , is the design margin; If the starting device and the ending device types are inconsistent, the shortest distance between the device and the cable channel inlet position is calculated , = , the shortest distance between the secondary device screen cabinet and the cable channel outlet is , , and the calculation method of is the same, the height difference between the cable inlet channel and the cable outlet channel is , and the actual cable laying length is .

[0013] The present application has the following beneficial effects: The application extracts three-dimensional coordinates of electrical equipment of a transformer substation, three-dimensional coordinates of cable import and export positions, three-dimensional coordinates of laying paths, and proposes a shortest cable laying path planning algorithm, so that the cable inventory cable length can be quickly and accurately counted, human errors are avoided, the cable length counting accuracy and efficiency are improved, the shortest connection path between electrical equipment is provided, the cable laying length is reduced, and the application has significant engineering, practical and popularization values. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The application discloses a transformer substation electrical secondary cable shortest laying path planning and length automatic counting method flowchart.

[0015] Figure 2 The application discloses a transformer substation outdoor cable laying path schematic diagram.

[0016] Figure 3 The application discloses a secondary equipment indoor cable laying path schematic diagram.

[0017] Figure 4 The application discloses a device three-dimensional coordinate extraction module schematic diagram.

[0018] Figure 5 The application discloses a laying path key node extraction module schematic diagram. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the application clearer, the application is further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application and do not limit the application.

[0020] The application discloses a transformer substation electrical secondary cable shortest laying path planning and length automatic counting method, which obtains three-dimensional coordinates of key nodes of a cable laying path in a transformer substation layout diagram, three-dimensional coordinates of electrical equipment and cable channel import and export positions, and accurately and automatically obtains electrical secondary cable purchase length by using a shortest path planning algorithm. The method comprises the following steps: S1: drawing an electrical secondary cable laying path tree diagram on a transformer substation CAD layout diagram.

[0021] The cable laying path tree diagram is a graphical tool for representing a cable laying path, which clearly shows the cable direction, branch condition and relationship between nodes through a tree structure.

[0022] S2: marking electrical primary equipment, electrical secondary equipment and cable import and export channels in the transformer substation CAD layout diagram, and the equipment marking names are consistent with the inventory equipment names. S3: Extract the key node three-dimensional coordinates of the cable laying path, the key node is the inflection point on the cable path, and the intersection three-dimensional coordinates of each cable laying path are obtained. The three-dimensional coordinates of each point are displayed in CAD; S4: Extract the three-dimensional coordinates of the electrical primary equipment, electrical secondary equipment and cable import and export position. The three-dimensional coordinates of the cable import and export are displayed in CAD; S5: Match the start and end device names of the inventory equipment with the substation device tag names, and assign the inventory equipment type and device three-dimensional coordinates in CAD; S6: Calculate the projection distance of each electrical equipment to each path line, obtain the nearest path line adjacent to the electrical equipment and the corresponding projection distance and projection three-dimensional coordinates; Regarding the projection distance of the equipment to the nearest path line, after calculating the projection distance of the electrical equipment to each path line in CAD, the nearest distance value and the corresponding path line are recorded, and the three-dimensional coordinates of the projection point of the electrical equipment on the nearest path line are recorded.

[0023] S7: According to the obtained nearest path line adjacent to the electrical equipment, and according to the intersection three-dimensional coordinates of each laying path line, a cable shortest laying path planning algorithm is proposed to obtain the shortest laying path from the start device to the end device; S8: Considering a certain design margin and the height difference of the cable import and export channel position, the laying distance between the start device and the end device is obtained. The design margin is determined by experience based on the number of inflection points on the cable laying path.

[0024] The S1 step includes: S11: Draw n1 polyline from the start point of the outdoor cable trench to the cable import position, wherein the value of n1 is determined according to actual needs.

[0025] S12: Draw n2 polyline from the cable trench exit to the back of the electrical secondary equipment, wherein the value of n2 is determined according to actual needs.

[0026] In the S5 step, the inventory equipment and the electrical primary equipment name and electrical secondary equipment name extracted in CAD are compared. If the names are consistent, the inventory equipment type and device three-dimensional coordinate value are assigned in CAD.

[0027] The S6 step includes: S61: Loop to calculate the projection distance and projection three-dimensional coordinates of the electrical equipment to each segment of the cable laying path; The cable laying path is divided into multiple sections by the inflection points on the laying path, and when there are n inflection points on the cable laying path, the cable laying path is divided into n+1 sections.

[0028] In the present application, the projection distance of the electrical equipment to each section of the cable laying path is divided into vertical projection distance and oblique projection distance, and when the vertical projection point of the electrical equipment is located on the n section of the path line, the projection distance of the electrical equipment to the n section of the path line is the vertical projection distance of the electrical equipment to the n section.

[0029] After the projection distance of the electrical equipment to each section of the cable laying path is calculated in CAD, the nearest distance value and the position of the corresponding path section are recorded, and the three-dimensional coordinates of the projection point of the electrical equipment on the corresponding path section are recorded.

[0030] In the present application, whether the vertical projection point of the electrical equipment is located on the n section of the path line is determined by the coordinate value of the vertical projection point of the electrical equipment.

[0031] The S7 step is the shortest laying path planning step, which comprises the following steps: S71: The three-dimensional intersection point coordinates obtained in the S3 step are constructed into a three-dimensional intersection point coordinate matrix; S72: The cable laying path set from the starting point equipment to the terminal point equipment is set as an empty set R; In the S72 step, the starting point equipment and the terminal point equipment corresponding to the starting point equipment can be informed from the inventory equipment, and the S72 step records the coordinates of all inflection points between the starting point equipment and the terminal point equipment, the cable inlet and outlet coordinates, and sets the set of all inflection point coordinates and cable inlet and outlet coordinates as an empty set R.

[0032] S73: Whether the starting point equipment and the terminal point equipment are on the same laying path line is determined by the coordinate value, and if yes, the laying path line is input into the cable laying path set, the shortest cable laying path is the laying path line, and the process is ended, otherwise, the step S74 is entered; S74: According to the cable laying path intersection point matrix, the laying path line set A intersecting with the projection line segment of the terminal point equipment is obtained, the projection line segment corresponding to the starting point equipment and the laying path line intersecting with the projection line segment are obtained, and the laying path line is placed in set B; for example, the terminal point equipment is closest to the d path line, and the points where the d path line intersects with other path lines are set as set A; the starting point equipment is closest to the e path line, and the points where the e path line intersects with other path lines are set as set B.

[0033] S75: Obtain all intersections of set B and set A, and obtain the cable laying path where the intersection point is located according to the intersection, and place the cable laying path where the intersection point is located in set R; S76: According to the intersection point set of the cable laying path, calculate the cable laying length under the corresponding cable laying path, and obtain the shortest length and the corresponding laying path.

[0034] The steps of the S8 step cable length automatic counting method are: S81: Compare the types of the starting point device and the ending point device; S82: If the types of the starting point device and the ending point device are consistent, then according to the projection three-dimensional coordinates of the device on the laying path, the projection distance , the internal cable connection length of the device , the shortest laying path length obtained , according to the number of nodes on the laying path line, consider the size of the cable turning radius, and consider the design margin accordingly , output the final cable length as ; S83: If the types of the starting point device and the ending point device are inconsistent, then use the method of step S82 to calculate the shortest distance from the device to the cable channel inlet position , = , the shortest distance from the second device screen cabinet to the cable channel outlet , The calculation method of is the same, the height difference between the cable inlet channel and the cable outlet channel , and the final cable length is output as .

[0035] In the embodiment of the application, the technical scheme is described with a 220kV substation project, as shown in the drawings, a shortest laying path planning and length automatic counting method for electrical secondary cables of a substation includes the following steps: drawing an outdoor cable laying path in a CAD plane layout of the substation, as shown in the drawings, five polyline segments are drawn from the starting point position of the cable trench to two cable inlet positions; drawing an outdoor cable laying path in the plane layout of the substation, as shown in the drawings, four polyline segments are drawn from the cable outlet position around the electrical secondary device screen cabinet. As shown in the drawings, according to the developed module, the outdoor cable laying path and the indoor cable laying path are respectively framed; and the three-dimensional coordinates of the key nodes of the polyline segments are obtained. Figure 1 Figure 2 Figure 3 Figure 4

[0036] As​​​​Figure 2 and 3 As shown in the figure, the name is marked at the primary equipment, the secondary equipment and the cable inlet and outlet in the substation CAD plan layout respectively, the name is consistent with the cable inventory equipment name, the electrical primary equipment, the electrical secondary equipment and the cable inlet and outlet passage position are framed respectively, and the corresponding three-dimensional coordinate values are obtained; The inventory equipment name is matched with the electrical equipment name extracted from the CAD, the equipment type and the corresponding three-dimensional coordinate values are given; The projection distance of the equipment to the corresponding nearest laying path and the projection three-dimensional coordinate are calculated, and the specific steps are as follows: 1) The projection distance of each electrical equipment to each section of cable laying path and the projection three-dimensional coordinate are calculated; 2) Whether the projection three-dimensional coordinate is in the section is judged, if not, the distance of the electrical equipment to the section is the distance between the three-dimensional coordinate of the electrical equipment and the three-dimensional coordinate of the starting point of the section; otherwise, the projection distance, the projection three-dimensional coordinate and the projection position are output.

[0037] 3) The minimum projection distance is taken, and the corresponding laying path line, the corresponding projection three-dimensional coordinate and the position in the multiple sections are obtained.

[0038] The shortest laying path from the starting point equipment to the terminal point equipment is obtained by the following method: 1) A three-dimensional intersection coordinate matrix is constructed according to the three-dimensional intersection coordinate obtained in step 3 of claim (1); 2) The cable laying path set from the starting point equipment to the terminal point equipment is set as an empty set R; 3) Whether the starting point equipment and the terminal point equipment are on the same laying path line is judged; if yes, the laying path line is input into the cable laying path set, the shortest cable laying path is the laying path line, and the process is ended, otherwise, step 3 is entered; 3) According to the cable laying path intersection matrix, the laying path line set A intersecting with the projection section of the terminal point equipment is obtained, the projection section corresponding to the starting point equipment and the laying path line intersecting with the projection section are obtained, and the laying path line is placed in set B; 4) All intersections existing between set B and set A are obtained, and the corresponding cable laying path is obtained according to the intersection, and the obtained cable laying path is placed in set R; 5) According to the obtained cable laying path set, the cable laying length under the corresponding cable laying path is calculated, and the shortest length and the corresponding laying path are obtained.

[0039] The cable length between the starting point equipment and the terminal point equipment is automatically obtained by the following method: 1) The types of the starting point equipment and the terminal point equipment are compared; 2) If the starting device and the ending device are of the same type, the projected distance is calculated according to the three-dimensional coordinates of the projection of the device on the laying path , the internal cable connection length of the device , the shortest laying path length is obtained according to the obtained shortest laying path length , the cable turning radius is considered according to the number of nodes on the laying path line, and the design margin is considered accordingly , and the final cable length is output as ; 3) If the starting device and the ending device are of different types, the shortest distance from the device to the cable channel inlet position is calculated by the method of step 2 , the shortest distance from the device screen cabinet to the cable channel outlet , the height difference between the cable inlet channel and the cable outlet channel , and the final cable length is output as .

[0040] The accuracy of the program is verified by an actual project case. The distances from the primary device to the secondary device, from the primary device to the primary device, and from the secondary device to the secondary device are respectively calculated in the figure and compared with the calculation results of the present application. The distance from the grounding transformer switch cabinet 1GP to the main transformer protection A screen TPA is calculated. First, determine the device type from the primary device to the secondary device, then identify the path from 1GP to the cable inlet channel position F H IN, F H D IN, the cable laying path from the cable outlet to TPA is OUT 2 3, the shortest cable laying path is automatically obtained as F 4 3 2, the shortest cable laying path is automatically obtained as F H IN OUT 2 3, the distance from the grounding transformer switch cabinet 1GP to the main transformer protection A screen TPA is measured in the figure as 95 meters, and the automatically calculated distance of the present application is 95.26 meters, which is basically consistent with the length manually counted in the figure. The laying path from the grounding transformer switch cabinet 1GP to the fan inlet cabinet 3GP is F H, the distance between the starting device and the ending device is measured in the figure as 14 meters, and the automatically calculated distance of the present application is 14.23 meters, which is basically consistent with the length manually counted in the figure. The path from CP to DCP1 in the figure has 2 6 5, 2 3 5, The shortest path of the cable laying obtained by the application is 2 3 5, The measured distance between the starting device and the terminal device on the path is 21 meters, and the calculated distance by the application is 21.04 meters, which is basically consistent with the length manually counted on the drawing. Therefore, the application can quickly and accurately count the cable length.

[0041] The cable length counted manually by the project is 26 km, and the cable length counted by the application through the shortest path planning algorithm is 23 km, saving 3 km of cable length. The application only needs 10 minutes from starting to mark the device coordinates, laying the path line to obtaining the cable laying path and length, while the traditional manual counting needs 6 hours.

Claims

1. A method for planning the shortest laying path and automatically calculating the length of secondary electrical cables in substations, characterized in that, The method includes: Draw a tree diagram of the electrical secondary cable laying path on the substation layout plan; The primary electrical equipment, secondary electrical equipment, and cable inlet / outlet channels are marked on the substation layout diagram, and the equipment marking names are consistent with the equipment names in the inventory. Extract the three-dimensional coordinates of key nodes in the cable laying path, where the key nodes are inflection points on the laying path, and obtain the three-dimensional coordinates of the intersection points of each cable laying path. Extract the three-dimensional coordinates of the primary electrical equipment, secondary electrical equipment, and cable inlet / outlet positions; Match the starting and ending equipment names in the inventory with the equipment label names in the substation layout diagram, and assign equipment types and three-dimensional coordinates to the equipment in the inventory. Calculate the projected distance from each electrical device to each path line, and obtain the nearest adjacent path line of each electrical device, as well as the corresponding projected distance and projected 3D coordinates; Based on the nearest adjacent path of the electrical equipment and the three-dimensional coordinates of the intersection of each laying path, the shortest laying path from the starting device to the ending device is obtained. The actual laying length between the starting and ending devices is obtained by considering design margin, height difference between cable inlet and outlet channels, projected distance from electrical equipment to adjacent path lines, and the shortest laying path from the starting device to the ending device.

2. The method for planning the shortest laying path and automatically calculating the length of secondary electrical cables in a substation according to claim 1, characterized in that, The step of drawing a tree diagram of the electrical secondary cable laying path on the substation layout diagram includes: drawing n1 polylines from the starting point of the outdoor cable trench to the cable inlet, and drawing n2 polylines from the outlet of the cable trench to the back of the electrical secondary equipment panel.

3. The method for planning the shortest laying path and automatically calculating the length of secondary electrical cables in a substation according to claim 1, characterized in that, The calculation of the projected distance from the electrical equipment to each path line, and the acquisition of the nearest adjacent path line of the electrical equipment and the corresponding projected distance and projected three-dimensional coordinates, include: calculating the projected distance from the electrical equipment to each segment of all path lines in CAD, recording the nearest distance value and the corresponding path line and the number of segments on the path line, and recording the three-dimensional coordinates of the projection point of the electrical equipment on the nearest adjacent path line.

4. The method for planning the shortest laying path and automatically calculating the length of secondary electrical cables in a substation according to claim 3, characterized in that, After calculating the projected distances from the electrical equipment to each path in the CAD, the closest distance value and the corresponding path are recorded. This includes: the cable laying path is divided into segments by inflection points; when there are n inflection points on the cable laying path, the cable laying path is divided into n+1 segments; the projected distances from the electrical equipment to each segment of the cable laying path are divided into vertical projected distances and oblique projected distances; when the vertical projection point of the electrical equipment is located on the nth segment of the path, the projected distance from the electrical equipment to the nth segment of the path is the vertical projected distance from the electrical equipment to the nth segment; when the electrical equipment... When the vertical projection point of the equipment is not on the nth segment of the path, the projection distance from the electrical equipment to the nth segment is the oblique projection distance from the electrical equipment to the nth segment. The oblique projection distance is the distance from the electrical equipment to the left or right end point of the nth segment, and the oblique projection distance is the smaller value between the distance from the electrical equipment to the left or right end point of the nth segment. After calculating the projection distance from the electrical equipment to each segment of the cable laying path in CAD, record the closest distance value and the position of the corresponding path segment, and record the three-dimensional coordinates of the projection point of the electrical equipment on the corresponding path segment.

5. The method for planning the shortest laying path and automatically calculating the length of secondary electrical cables in a substation according to claim 1, characterized in that, The shortest laying path planning from the starting point equipment to the ending point equipment includes: The obtained 3D intersection point coordinates are constructed into a 3D intersection point coordinate matrix; Set the set of cable laying paths from the starting device to the ending device as an empty set R; Determine whether the starting device and the ending device are on the same laying path; if so, input the laying path into the cable laying path set, the shortest cable laying path is the laying path, and end; otherwise, according to the cable laying path intersection matrix, obtain the laying path lines that intersect with the projection line segment of the ending device as set A, and obtain the projection line segment corresponding to the starting device and the laying path line that intersects with it as set B. Obtain all intersections between set B and set A, and based on the intersections, obtain the cable laying paths where the intersection points are located, and place the obtained cable laying paths into set R; S76: Based on the obtained set of cable laying paths, calculate the cable laying length under the corresponding cable laying path, and obtain the shortest length. And the corresponding laying path.

6. The method for planning the shortest laying path and automatically calculating the length of secondary electrical cables in a substation according to claim 5, characterized in that, Setting the set of cable laying paths from the starting device to the ending device as an empty set R includes: determining the starting device and the corresponding ending device based on the list of devices, and setting the set of coordinates of all inflection points, cable inlet and outlet coordinates between the starting device and the ending device as an empty set R.

7. The method for planning the shortest laying path and automatically calculating the length of secondary electrical cables in a substation according to claim 5, characterized in that, The statistics on the laying distance between the starting point equipment and the ending point equipment include: Compare the types of the starting and ending devices; If the starting and ending equipment types are the same, the actual cable laying length is: ,in This refers to the projected distance between the equipment and the laying path. Here, represents the internal cable connection length of the equipment, and represents the calculated shortest laying path length. , For design margin; If the starting and ending equipment types are different, calculate the shortest distance from the equipment to the cable channel inlet. , = The shortest distance from the secondary equipment cabinet to the cable channel outlet , and The calculation method is the same, and the height difference between the cable inlet channel and the cable outlet channel is the same. The actual cable laying length is .

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