The conductor consists of seven strands of steel surrounded by four layers of aluminium.
Construction[ edit ] A man working on powerlines in Nauru Towers for support of the lines are made of wood as-grown or Power transmission line projectsteel or aluminum either lattice structures or tubular polesconcrete, and occasionally reinforced plastics.
The bare wire conductors on the line are generally made of aluminum either plain or reinforced with steelor composite materials such as carbon and glass fiberthough 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, and to provide reliable support for the conductors, resilience to storms, ice loads, earthquakes and other potential damage causes.
Low voltage LV — less than volts, used for connection between a residential or small commercial customer and the utility. Medium voltage MV; distribution — between volts 1 kV and 69 kV, used for distribution in urban and rural areas.
Ultra high voltage UHV — higher than kV. The Financial Times reported UHV lines are a "game changer", making a global electricity grid potentially feasible. StateGrid said that compared to conventional lines, UHV enables the transmission of five time more power, over six times the distance.
Transmission tower Structures for overhead lines take a variety of shapes depending on the type of line. Structures may be as simple as wood poles directly set in the earth, carrying one or more cross-arm beams to support conductors, or "armless" construction with conductors supported on insulators attached to the side of the pole.
Tubular steel poles are typically used in urban areas. High-voltage lines are often carried on lattice-type steel towers or pylons. For remote areas, aluminum towers may be placed by helicopters.
Each structure must be designed for the loads imposed on it by the conductors. Where conductors are in a straight line, towers need only resist the weight since the tension in the conductors approximately balances with no resultant force on the structure.
Flexible conductors supported at their ends approximate the form of a catenaryand much of the analysis for construction of transmission lines relies on the properties of this form.
Depending on the design criteria for a particular line, semi-flexible type structures may rely on the weight of the conductors to be balanced on both sides of each tower.
More rigid structures may be intended to remain standing even if one or more conductors is broken. Such structures may be installed at intervals in power lines to limit the scale of cascading tower failures. Each structure may be stabilized considerably by the use of guy wires to counteract some of the forces applied by the conductors.
In some cases the lines are buried to avoid this, but this " undergrounding " is more expensive and therefore not common. For a single wood utility pole structure, a pole is placed in the ground, then three crossarms extend from this, either staggered or all to one side.
The insulators are attached to the crossarms.
For an "H"-type wood pole structure, two poles are placed in the ground, then a crossbar is placed on top of these, extending to both sides. The insulators are attached at the ends and in the middle. Lattice tower structures have two common forms. One has a pyramidal base, then a vertical section, where three crossarms extend out, typically staggered.
The strain insulators are attached to the crossarms. Another has a pyramidal base, which extends to four support points.The Kusile power station project, which is located near the existing Kendal power station, in the Nkangala district of Mpumalanga, will comprise six units, each rated at an MW installed capacity for a total capacity of 4 MW.
Manchester Newspapers: Power project may ease taxes in local towns A monumental clean-energy project may shift some of the tax burden from Washington County taxpayers. Details about the Champlain Hudson Power Express, including routing and impact upon the local area, were presented at a Putnam town meeting last Thursday by Josh Bagnato, vice president of project development for Transmission.
CPS Energy has several smart, easy ways to help you save energy and money and become more energy efficient - for both residential and commercial customers. The TransWest Express Transmission Project is a high-voltage interregional electric transmission system developed by TransWest Express LLC.
The TWE Project is critical new infrastructure that will deliver electricity generated by renewable resources and will strengthen the power grid that serves the Western United States.
A project map from American Transmission Company (ATC), dated August , is available here. Stated Purpose: The purpose of this line is to address electric system reliability issues--both locally and in the Midwest--while enabling the transfer of renewable energy from wind farms in .
The Boardman to Hemingway Transmission Line Project is proposed by Idaho Power to construct, operate and maintain a new electric transmission line, consisting of approximately miles of single circuit kilovolt transmission line. Idaho Power proposes to build the kV transmission line from Boardman, Oregon to the Hemingway Substation being constructed near Melba, Idaho.