To make the design of overhead cable transmission lines safe, reliable, and economical, it is necessary to conduct a comprehensive and detailed investigation and study of the conditions of the lines in order to properly select the path plan of the line.
The purpose of the route selection is to choose the most reasonable line route that is in line with the national construction guidelines and policies between the starting and ending points of the line. Therefore, line selection personnel should follow various guidelines and policies when selecting route routes, comprehensively consider factors such as safe operation, economical efficiency and convenient construction, and then make a comprehensive comparison to select a technically and economically reasonable route route. . Line selection is generally divided into two situations: selection on the indoor map and on-site selection.
1. Indoor line selection
The map selection line is performed on a 50,000 or 100,000 map. If necessary, a topographic map with a scale greater than 50,000 can also be used. The steps are as follows:
(1) Mark the starting point and the necessary point of the line on the map first, and then, based on the collected data, avoid some facilities and the scope of influence, taking into account factors such as terrain and traffic conditions, and give the shortest route route principle. Several programs, after comparison, retain two better solutions.
(2) According to the system's long-range plan, calculate the short-circuit current, verify the impact on important telecommunication lines, and propose correction schemes or protective measures for the routes.
After all the above tasks, a reasonable plan was selected through technical and economic comparison.