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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.
This type of travelling can be extremely dangerous and even life-threatening, because there is a risk of death or serious injury due to falling off a moving train, electrocution by the power supply (overhead catenary wire, third rail, current collectors, resistors, etc.), colliding with railway infrastructure such as bridges, tunnels, station ...
For at least four years, one of Mexico's largest power plants violated an environmental safeguard that prevents emissions of deadly pollutants, according to documents seen by Reuters. The Tula ...
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.
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]
Seismic activity may displace transmission line support structures, disturbing the planned spacing of conductors and possibly producing a clash. Acts of vandalism targeted at power lines introduce another reason for conductor clashing. Deliberate acts of hurling objects at power lines can induce drooping and the subsequent collision of wires. [4]
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.