Expansion of the European Energy Network

Amprion and the Belgian transmission system operator Elia built the first direct power connection between Germany and Belgium. The approximately 90 km long direct current underground cable is named ALEGrO (Aachen Liège Electricity Grid Overlay) and was included in the European Union’s list of PCI projects (Projects of Common Interest). Amprion recently expanded the power grid using egeplast protective pipes for high-voltage cables.

As part of the expansion of the European energy network, a direct current underground cable was built starting in October 2018. For this purpose, a 320 kV connection from Oberzier (Germany) to Liège (Belgium) was established by November 2020. The grid operator Amprion uses the high-temperature resistant egeplast Power Protect with a low-friction and abrasion-resistant bright inner layer. During the establishment of a conduit system for a 320 kV cable from Oberzier to the Belgian border, the Installation was carried out by the AAA consortium, comprising Klaus Stewering (Borken), Heitkamp & Hülscher (Stadtlohn), Ulrich Bogenstahl (Legden), and RN Rohrleitungsbau Niederrhein (Krefeld). The grid operator Elia was responsible for the expansion of the route on the Belgian side.
Of the approximately 90 km, about 40 km are on the German side. These were installed using open-trench (cable trench) and trenchless methods (HDD, pipe jacking). The power system consists of two parallel installed cable protection pipes.

30 km of this were implemented using the open-trench method. For Installation using the open-trench method, the egeplast Power Protect with a push-fit socket system in the dimension 250 x 11.4 mm was used for straight route sections. For curved sections, the 250 x 11.4 mm pipe is used in combination with a High-T PE electrofusion coupler.
It is a protective pipe for high and extra-high voltage cables, which features increased thermal stability to withstand high thermal stresses. Excellent fitting accuracy during the production of the socket connections enables easy handling and achieves a high Installation speed. The inspection-friendly bright inner layer is low-friction and abrasion-resistant, thus offering optimal conditions for cable pulling.

“The chosen construction method allowed for Installation rates of up to 100 m in combination, or 18 pipe lengths per day. A positive aspect during construction was the very easy and quick assembly of the pipe sockets, where the factory-set insertion depth marking proved to be very helpful,” explains Manuel Schneidereit, Senior Site Manager of the Amprion ALEGrO Aachen (AAA) consortium. The long socket design offers increased safety.

Underpasses beneath motorways and ICE lines were carried out using the pipe jacking method. Drilling lengths were up to 80 m at a depth of up to 8 m. For the installed cable system, a 320 kV cable is used, which is pulled into the cable protection pipe system. The goal is to achieve pulling lengths of up to 1,140 m.

All necessary accessory components were supplied by egeplast as a system provider – these include double push-fit sockets (long version), transition pieces, electrofusion couplers, end caps, socket covers, and rental tools (internal bead removers and butt welding machines).