An overhead power line is an electric power transmission line suspended by towers or utility poles. Since most of the insulation is provided by air, overhead power lines are generally the lowest-cost method of transmission for large quantities of electric energy. Towers for support of the lines are made of wood (as-grown or laminated), steel (either lattice structures or tubular poles), concrete, aluminum, and occasionally reinforced plastics. The bare wire conductors on the line are generally made of aluminum (either plain or reinforced with steel, or sometimes composite materials), though some copper wires are used in medium-voltage distribution and low-voltage connections to customer premises. A major goal of overhead power line design is to maintain adequate clearance between energized conductors and the ground so as to prevent dangerous contact with the line. Today overhead lines are routinely operated at voltages exceeding 765,000 volts between conductors, with even higher voltages possible in some cases.
Read more about Overhead Power Line: Classification By Operating Voltage, Structures, Insulators, Conductors, Compact Transmission Lines, Low Voltage, Train Power, Further Applications, Use of Area Under Overhead Power Lines, History
Famous quotes containing the words overhead, power and/or line:
“What a fog! Plane been buzzin’ around overhead for the last half hour. Must be like trying to find your way through the inside of a cow. I never did see such a country. Even the birds are walkin’.”
—Dalton Trumbo (1905–1976)
“It has been the struggle between privileged men who have managed to get hold of the levers of power and the people in general with their vague and changing aspirations for equality, for justice, for some kind of gentler brotherhood and peace, which has kept that balance of forces we call our system of government in equilibrium.”
—John Dos Passos (1896–1970)
“A line will take us hours maybe;
Yet if it does not seem a moment’s thought,
Our stitching and unstitching has been naught.”
—William Butler Yeats (1865–1939)