Fir tree pole

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The Christmas tree mast is an overhead line mast for the arrangement of conductor cables in three levels (three-level arrangement ), in which the lowest crossbeam has a larger span than the middle one and this has a larger span than the upper one.

use

Particularly in the early days of the supra-regional network in the 1920s and 1930s, many lines were erected on Christmas tree poles in Germany, independently of energy supply companies. Most of the 110 kV lines that were being built in the RWE network area at that time were laid on such masts, as were the two-circuit 110 kV lines of the Bayernwerk and the joint stock company Sächsische Werke . In many places where the line poles have been renewed, fir tree poles have also been built to replace them. The 60 kV network of PreußenElektra was also laid on fir tree poles; these lines were almost completely dismantled in the course of the voltage change from 60 kV to 110 kV in the supply area.

In Austria, too, this type of mast was used on the first 110 kV line sections, for example on the Ernsthofen - Gresten - Vienna and Hessenberg - Ternitz - Ebenfurth lines .

The RWE's 220-kV transmission network, which expanded from the late 1920s to the mid-1940s, used fir tree poles in slightly larger dimensions. Such masts can also be found on some of the remaining sections of a 220 kV line built during the Second World War from the Brauweiler substation to Jupille , Belgium , which also ran through the Netherlands .

In very isolated cases, four circuits were laid on masts with a double Christmas tree arrangement, for example the line between the Essen-Karnap power plant and Duisburg-Hamborn or the Rhine crossing at Duisburg-Rheinhausen. When the Harbke – Spandau and Zschornewitz – Spandau lines, which ran between the state of Brandenburg and the (West) Berlin urban area, were changed after the construction of the Berlin Wall , they were both on a common route at Schönwalde-Glien in the immediate vicinity of the wall strip laid, which was laid on masts with a double Christmas tree arrangement, i.e. six trusses. Presumably in order to keep the line route as narrow as possible, this unusual design was used here.

Some lines from the 1920s in Saxony were equipped with an additional earth cable traverse on fir tree poles (e.g. Niederwartha - Dresden -Süd and Dresden-Süd - Hirschfelde power station ). In addition, some lines in the central German network, which extended from the Zschornewitz power station , had fir tree poles with the opposite arrangement, with the widest traverse at the top.

Since around the 1960s, new overhead lines in Germany have generally no longer been built on fir tree poles, but on Danube or barrel masts . Danube masts offer a compromise between mast height and route width and barrel masts require a less wide route, but higher masts.

  • Fir tree poles near Hamm

  • Older Christmas tree mast of RWE: left circuit 110 kV, right 220 kV

  • Older Christmas tree mast from RWE for 110 kV

  • Fir tree pole in Italy

  • 110 kV Christmas tree mast with earth rope horns for two earth ropes

  • Fir tree mast on one side of a medium-voltage line in Silesia

  • Fir tree mast of a medium voltage line near Dresden with standing insulators

modification

Fir tree masts for overhead lines with two three-phase circuits (i.e. a total of 6 conductor cables) carry a conductor cable at the ends of each traverse. In four phase circuits (12 conductor cables), the upper two cross-members on each page together form a three-phase circuit (corresponding to the wire ropes at the two-level pylon ). The second three-phase circuit on each side is then carried by the lowest traverse.

  • Older Christmas tree mast with an extra traverse for earth ropes near Hirschfelde

  • Fir tree poles with the reverse arrangement at Bolesławiec ; this line originally came from the Trattendorf power station and is now part of the Polish network

  • Six-level mast of the Rheinhausen overhead line crossing for 220/110 kV, systems for 110 kV removed

  • Six-level mast in inverted Christmas tree arrangement in Poland

  • Construction in Japan with 9 levels for a total of 6 systems

  • Fir tree mast for 4 systems (110 kV) near Wiesbaden

  • Fir tree pole for 4 systems

Individual evidence

  1. ↑ 110 kV line in the rear-view mirror , Gresten-Land community, July 6, 2016
  2. ↑ On aerial photos from 1953, the two lines can be seen in their original course, pictures from 2000 still show the line (which no longer exists) later with double Christmas tree poles.
  3. ↑ In this video the line can be seen at about 9:40 minutes
  4. ↑ Lecture notes high voltage technology FS09, Part Apparate II ( Memento of the original from April 27, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. ETH Zurich (PDF file, accessed on February 13, 2011; 9.5 MB), in particular slide 9 @1@ 2Template: Webachiv / IABot / www.eeh.ee.ethz.ch