An electrical insulator is a material in which electric current does not flow freely. The atoms of the insulator have tightly bound electrons which cannot readily move. Other materials—semiconductors and conductors—conduct electric current more easily. The property that distinguishes an insulator is its resistivity; insulators have higher resistivity than semiconductors or conductors. The most common examples are non-metals.
A transmission tower is a tall structure, usually a lattice tower made of steel that is used to support an overhead power line. In electrical grids, transmission towers carry high-voltage transmission lines that transport bulk electric power from generating stations to electrical substations, from which electricity is delivered to end consumers; moreover, utility poles are used to support lower-voltage sub-transmission and distribution lines that transport electricity from substations to electricity customers.
The HVDC Volgograd–Donbass is a 475 kilometres (295 mi) long bipolar ±400 kV high voltage direct current powerline used for transmitting electric power from Volga Hydroelectric Station at Volgograd in Russia to Donbas in eastern Ukraine and vice versa.
HVDC Vancouver Island is a de-energized high-voltage direct current interconnection owned by BC Hydro that runs between Arnott Substation (ARN) in Delta, British Columbia at 49°5′31″N123°2′31″W on the Canadian mainland, and the Vancouver Island Terminal (VIT) in Duncan, British Columbia on Vancouver Island at 48°49′39″N123°42′55″W. It went into operation in 1968 and was extended in 1977. HVDC Vancouver Island consists of three overhead line sections with a total length of 42 kilometres and two submarine cable sections with a length of 33 kilometres. Pole 1 ceased operation in 2014, and Pole 2 ceased operation in 2016. The infrastructure remains in place and portions may be re-used in the future.
The Pylons of Messina are two free-standing steel towers, the Sicilian one in Torre Faro and the Calabrian one in Villa San Giovanni. They were used from 1955 to 1994 to carry a 220 kilovolt power line across the Strait of Messina, between the Scilla substation in Calabria on the Italian mainland at 38°14′42″N15°40′59″E and the Messina-Santo substation in Sicily at 38°15′57″N15°39′04″E.
The Pylons of Cádiz, also known as the Towers of Cádiz, are two 158 m (518 ft)-tall pylons supporting a double-circuit 132 kV three-phase AC powerline over the bay of Cádiz, Spain, running from Puerto Real Substation to the substation of the former Cádiz Thermal Power Station, situated on the peninsula upon which the city of Cádiz stands.
An overhead line crossing is the crossing of an obstacle—such as a traffic route, a river, a valley or a strait—by an overhead power line. The style of crossing depends on the local conditions and regulations at the time the power line is constructed. Overhead line crossings can sometimes require extensive construction and can also have operational issues. In such cases, those in charge of construction should consider whether a crossing of the obstacle would be better accomplished by an underground or submarine cable.
An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy along large distances. It consists of one or more conductors suspended by towers or poles. Since the surrounding air provides good cooling, insulation along long passages, and allows optical inspection, overhead power lines are generally the lowest-cost method of power transmission for large quantities of electric energy.
The Suez Canal overhead powerline crossing is a major electrical power line built across the Suez Canal in 1998, located near Suez, Egypt. It is designed for two 500 kV circuits.
Bosporus overhead line crossings refers to the three transmission line crossings of the Bosporus, the strait in Istanbul, Turkey.
The Berlin 380 kV electric line is a 38.3-km double-circuit high-voltage electric three-phase power line in Berlin. An unusual system for a municipality, it was installed by the West Berlin Bewag utility company during the division of the city. Since 1951, West Berlin had been cut off from the East Berlin and East German power networks, and maintained an independent power generation capacity that was not connected to any other power grid. Berlin was connected to the western European power grid in 1994, following German reunification, by extending the 380 kV line.
A traction network or traction power network is an electricity grid for the supply of electrified rail networks. The installation of a separate traction network generally is done only if the railway in question uses alternating current (AC) with a frequency lower than that of the national grid, such as in Germany, Austria and Switzerland.
In an electric power transmission line, a suspension tower is where the conductors are simply suspended from the tower, the mechanical tension being the same on each side.
Transposition is the periodic swapping of positions of the conductors of a transmission line, in order to reduce crosstalk and otherwise improve transmission. In telecommunications this applies to balanced pairs whilst in power transmission lines three conductors are periodically transposed.
The Yangtze River power line crossings are overhead power lines that cross the Yangtze River in China. There are at least three power line crossings on the Yangtze River at Jiangyin, Nanjing, and Wuhu. The towers of the crossing in Jiangyin are among the highest in the world.
A strain insulator is an electrical insulator that is designed to work in mechanical tension (strain), to withstand the pull of a suspended electrical wire or cable. They are used in overhead electrical wiring, to support radio antennas and overhead power lines. A strain insulator may be inserted between two lengths of wire to isolate them electrically from each other while maintaining a mechanical connection, or where a wire attaches to a pole or tower, to transmit the pull of the wire to the support while insulating it electrically. Strain insulators were first used in telegraph systems in the mid 19th century.
GKK Etzenricht, an abbreviation of Gleichstromkurzkupplung Etzenricht, meaning Etzenricht HVDC-back-to-back station, was an HVDC back-to-back facility near Etzenricht in the district of Neustadt an der Waldnaab in Bavaria, Germany. It was built on the site of the Etzenricht substation, a 380 kV/220 kV/110 kV-substation, which went into service in 1970 and expanded afterwards several times. The facility was used between 1993 and 1995 for the exchange of power between Germany and the Czech Republic, operated by Bayernwerk AG.
The Rzeszów–Khmelnytskyi powerline is an electrical power transmission line between Ukraine and Poland. It is the only 750 kV-powerline in Poland, and one of a few in the European Union.
The Vetrino–Isaccea–Yuzhnoukrainsk powerline is the third 750 kilovolts powerline running from Ukraine to the European Union.
In the United Kingdom, powerlines cross rivers and estuaries either in the form of overhead lines or with cables carried in tunnels. Overhead power lines are supported on towers which are usually significantly taller than overland pylons and are more widely spaced to cross the river in a single span. Tall pylons ensure that the electricity cables which they support provide an adequate safety clearance for river traffic.
