used to transmit power over great distances; another set of transformers is required to step it back down to safer or more usable voltage levels at destination.
Electric power transmission with underground cable. Here (1) is the conductor for heavy currents and (3) the insulation for high voltages.
Power transmission is usually performed with overhead lines as this is the most economical way to do so. Underground transmission by high-voltage cables is chosen in crowded urban areas and in high-voltage direct-current (HVDC) submarine connections.
Electrical power transmission has replaced mechanical power transmission in all but the very shortest distances.
From the 16th century through the
industrial revolution to the end of the 19th century, mechanical power transmission was the norm. The oldest long-distance power transmission technology involved systems of push-rods or jerker lines (stängenkunst or feldstängen) connecting waterwheels to distant mine-drainage and brine-well pumps.[1] A surviving example from 1780 exists at Bad Kösen that transmits power approximately 200 meters from a waterwheel to a salt well, and from there, an additional 150 meters to a brine evaporator.[2] This technology survived into the 21st century in a handful of oilfields in the US, transmitting power from a central pumping engine to the numerous pump-jacks in the oil field.[3]
Mechanical power may be transmitted directly using a solid structure such as a
Agricola, connecting a waterwheel to numerous ore-processing machines.[4] While the machines described by Agricola used geared connections from the shafts to the machinery, by the 19th century, drivebelts would become the norm for linking individual machines to the line shafts. One mid 19th century factory had 1,948 feet of line shafting with 541 pulleys.[5]
repair garages. A pneumatic wrench (for instance) is used to remove and install automotive tires far more quickly than could be done with standard manual hand tools. A pneumatic system was proposed by proponents of Edison'sdirect current as the basis of the power grid. Compressed air generated at Niagara Falls would drive far away generators of DC power. The war of the currents ended with alternating current
(AC) as the only means of long distance power transmission.
Thermal power
Thermal power can be transported in pipelines containing a high heat capacity fluid such as oil or water as used in district heating systems, or by physically transporting material items, such as bottle cars, or in the ice trade.
Chemicals and fuels
While not technically power transmission, energy is commonly transported by shipping
