# Special powerlines



## Obelixx (Apr 14, 2005)

Are there special powerlines in your country?

With special powerlines, I mean powerline not used for three phase AC current, which is the most common form of electric power used for transmission.

Here are some pictures

*HVDC*

In Germany there are two HVDC powerlines, the Baltic-Cable ( http://en.wikipedia.org/wiki/Baltic_Cable ) and the Kontek ( http://en.wikipedia.org/wiki/Kontek ). HVDC Kontek is built in its whole length as underground cable, while Baltic-Cable has an overhead powerline section in Sweden. In Germany there is no HVDC powerline.









Overhead powerline of Baltic-Cable in Sweden. Both conductors are parallelized. The other pole consists of an underground cable and the Baltic Sea!









HVDC static inverter station Kruseborg of Baltic-Cable in Sweden

Between 1993 and 1995 there was an HVDC back-to-back station at Etzenricht ( http://en.wikipedia.org/wiki/Kontek ). It is now obsolete, because the powergrids of Germany and Czech are synchronised.









Etzenricht HVDC-back to back station









Very special pylons of an HVDC powerline in Zaire ( http://www.abb.com/global/abbzh/abb...e=us&m=9F2&c=C1256D71001E0037C1256C7D00387939 )

*Traction Current*

In Germany, Austria, Norway, Sweden and Switzerland most electric trains uses single phase AC with a frequency of 16.67 Hertz and a voltage of 15 kV.
In Norway, Sweden and some parts of Eastern Germany the three phase AC power is converted in the substations of the railway by rotating machines or electronic frequency converters in single phase AC with a frequency of 16.67 Hertz and a voltage of 15 kV. However in the most parts of Germany, Switzerland and Austria the railway companies have their own high-voltage grid. It is run with 110 kV in Germany and Austria and with 66 kV and 132 kV in Switzerland.
Powerlines for the railway companies can be find out very easily, because the numbers of conductors on the pylons are 2, 4 (most common) or 8, while on standard powerlines they are 3 or 6 (powerlines with 12 conductors can be as well powerlines for the public power grid or for the grid of the railways. However if insulators have different length or if there are branches with 3 or 6 conductors, they are for the public grid).
Sometimes circuits for traction current and for the public grid are mounted on the same pylon. For these pylons the number of conductors is in most cases 10 ( 4 conductors for traction current, 6 conductors for current for the public grid)
Because there are and were no HVDC overhead powerlines in Germany, Switzerland and Austria, there is no danger of confusion of powerlines for traction current and HVDC in these countries.









Most common pylon type used for traction current in Germany.
Powerlines for traction current run in most cases not in the neighboorhood of railway lines!


*Feeder lines of high power transmitters*

Sometimes the antennas of high power transmitters in the longwave, mediumwave or shortwave range are fed by overhead powerlines of special type.









Powerline for feeding the antenna at Topolna longwave transmitter, Czech









Powerline for feeding the antenna at Wilsdruff mediumwave transmitter, Germany (not in use any more)

Interestingly such lines were sometimes built even at new facilities as the longwave transmitter Solec Kujawski in Poland









Powerline for feeding the antennas at Solec Kujawski longwave transmitter in Poland. The facility was built in 1998/99!


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