Search results
Results from the WOW.Com Content Network
An overhead cable is a cable for the transmission of information, laid on utility poles. Overhead telephone and cable TV lines are common in North America. These poles sometimes carry overhead power lines for the supply of electric power. Power supply companies may also use them for an in-house communication network.
The first overhead power line was built from Necaxa to Mexico City and El Oro de Hidalgo in 1905, when the hydroelectric plant in Necaxa opened. This 60 kV power line also was the world's longest power line in 1905. Despite the age, parts of the power line are still in service. [22] Around 1930, central Mexico already had an interconnected grid.
High- and medium-voltage power lines in Łomża, Poland Extra high-voltage overhead line 750 kV. Overhead power transmission lines are classified in the electrical power industry by the range of voltages: Low voltage (LV) – less than 1000 Volts, used for connection between a residential or small commercial customer and the utility.
Bare-hand, or potential working involves placing the worker in direct electrical contact with an energized overhead line. The worker might work alongside the lines, from a platform that is suspended from them, or may sit or stand directly on the line itself. [3] In all cases, the worker's body is maintained at the same voltage as the line.
Overhead power lines range from 1kV for local distribution to 1,150 kV for ultra high voltage lines. These can produce electric fields up to 10kV/m on the ground directly underneath, but 50 m to 100 m away these levels return to approximately ambient. [20] Metal equipment must be maintained at a safe distance from energized high-voltage lines. [21]
A utility pole, commonly referred to as a transmission pole, telephone pole, telecommunication pole, power pole, hydro pole, telegraph pole, or telegraph post, is a column or post used to support overhead power lines and various other public utilities, such as electrical cable, fiber optic cable, and related equipment such as transformers and ...
This is a potentially dangerous fault condition. With ABC, a simultaneous disconnection of all conductors is more likely. In moister climates, tree growth is a significant problem for overhead power lines. ABC will not arc over if touched by tree branches. Although persistent rubbing is still a problem, tree-trimming costs can be reduced.
Corona discharges on the 380kV overhead power line over the Albula Pass (Switzerland) in foggy weather conditions (30 second long exposure) Coronas can generate audible and radio-frequency noise, particularly near electric power transmission lines. Therefore, power transmission equipment is designed to minimize the formation of corona discharge.