In view of the positive trend for the wind farms in Fläming (Brandenburg, Germany), the existing grid infrastructure continues to be expanded on an ongoing basis since January 2017. A 110 kV cable connection has been installed from the Petkus transformer station to the grid connection point Schönewalde Süd. The grid operator opted in favour of the high-temperature resistant protective pipes ege-com® Macroduct High-T PP and PE.

The installation of an empty conduit system for a 110 kV cable HT 1270 from the Petkus transformer station (UW) to the grid connection point (NVP) Schönewalde Süd was executed by the laying company Bohlen & Doyen Wiesmoor using both open-trench and trenchless installation methods. A pipeline route over a length of 25 km was performed based on open-trench installation. The points were connected taking the planned route. The route consists of two protective layer pipes with a prepared and an installed cable system. Installation of the cable system is level-compounded, with three cables next to each other, while the empty conduit system gets installed in a triangle. For areas in which open-trench pipeline construction is not feasible, such as around creeks, ditches, roads and river crossings, the crossing is performed by means of HDD drilling. For the cable system installed in this case, a 110 kV cable HT 1270 by NKT is used which is inserted into the empty conduit system. The goal is to realise insertion lengths of up to 1,800 m.

Expansion phase 2: 2 Empty conduit systems in open-trench construction, 1 system with cable | Source: Bautechnische Erläuterungen HT 1270_2016_11_28


For open-trench installation, the ege-com® Macroduct High-T PP system including a 200 x 9.1 mm coupler is used. It is a protected pipe for high and extra-high voltage cables featuring enhanced heat stability in order to withstand high thermal stress. Its easy handling makes for economical installation. “As a result, the laying performance reached a maximum up to 300 m in combination, so 150 straight lengths per day. One positive aspect associated with construction was the easy and quick joint installation associated, where the depth insertion mark provided by the factory turned out to be very helpful”, explains site manager Paul Eirich. The long-sleeve coupler contributes to enhancing the safety level, which presents particular advantages in the context of bending effects.

The underpasses were executed using the HDD method. In this context, drilling lengths were up to a maximum of 220 m at depths of up to 7 m and a drilling radius measuring around 60 m. For the HDD drillings, the ege-com® Macroduct High-T PP pipes measuring 225×13.4 mm were connected via butt welding. In the course of the welding process, damage-free removal of the inside weld bead was performed to prevent the formation of any weld edges before inserting the power cables. All accessory components required were supplied by egeplast as a systems provider, including double couplers (long design), transition pieces, electrofusion couplers, slip-on couplers, end caps and sleeve caps as well as seamlessly drawn bends. Thanks to productive cooperation and smooth logistics, the project has been able to press ahead successfully.

Project data

Project description: 110 kV – cable HT 1270 UW Petkus – NVP Schönewalde Süd
Challenges: Installation of an empty conduit system for a 110 kV cable system
Solution: Application of ege-com® Macroduct High-T PP and PE made of modified raw material with enhanced heat stability
Installation: Open-trench construction and trenchless installation using the horizontal directional drilling method (HDD)
Pipe System:
Parties involved in
the project:
Client: e.dis Netz GmbH
Planning: Omexon
Installation: Bohlen & Doyen GmbH
HDD: Bohlen & Doyen GmbH
Cable: NKT GmbH & Co. KG



Dipl.-Ing. Günter Albers
Bohlen & Doyen GmbH
Abteilungsleiter Landkabelbau
Tel: +49 4944 301 344
B. Eng. Paul Eirich
Bohlen & Doyen GmbH
Bauleiter Landkabelbau
Tel: +49 4944 301 517
Dipl.-Ing. Ralf Wolter
egeplast international GmbH
Product Management Cable Protection Systems
Tel: +49 2575 9710 430

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