Expansion of the European energy grid

Amprion and Belgium’s electricity transmission system operator Elia are in the process of creating the fi rst direct power connection between Germany and Belgium. This direct current underground cable, which is approx. 90 km long, has been named ALEGrO (Aachen Lüttich Electricity Grid Overlay) and has been registered as a PCI project (Projects of Common Interest) of the European Union. Amprion has taken on the expansion of the electricity grid using egeplast conduits for high-voltage cables.
As part of the ongoing expansion of the European energy grid, a DC underground cable connection is being constructed since October 2018. For this purpose, a 320-kV-connection from Oberzier (Germany) to Liège (Belgium) is to be installed by 2020. Transmission system operator Amprion decided to use the egeplast
ege-com® Macroduct High-T PE with a low-friction and abrasion-resistant light-coloured inner layer which is also resistant to high temperatures.
In establishing an empty conduit system for a 320-kV cable from Oberzier to the Belgian border, the installation is carried out by the AAA working committee consisting of the following fi rms: Klaus Stewering (Borken), Heitkamp & Hülscher (Stadtlohn), Ulrich Bogenstahl (Legden) and RN Rohrleitungsbau Niederrhein (Krefeld). The expansion of the pipe route on the Belgian side is the responsibility of transmission system operator Elia. Out of the approx. 90 km in total length, approx. 40 km are on the German side. The installation is carried out using open-trench installation (utility trenches) and trenchless installation (HDD, pipe jacking). The power system consists of two cable conduits installed in parallel.
30 km are being executed using the opentrench method. For open-trench installation, the ege-com® Macroduct High-T PE with a socket joint system with dimensions of 250 x 11.4 mm are being used for straight parts of the route. For pipe bend areas, the 250 x 11.4 mm pipe combined with a High-T PE electrofusion socket is being used.
A conduit for high- and extra-high-voltage cables providing enhanced thermal stability, it is fi t to withstand the high thermal load involved. The excellent fi t achieved in creating the sleeve connections ensures easy handling and accelerates laying speed. The inspectionfriendly, light-coloured low-friction inner layer is abrasion-resistant, thus providing optimum conditions for cable insertion.

“The construction technology used here made it possible to realise laying speeds of up to 100 m in bundles, that is, 18 rods per day. One positive aspect of during the execution of the construction project was the very fast and easy assembly of the pipe sockets, which was
greatly helped by the factory-marked insertion depth”, Manuel Schneidereit, the senior site engineer of ARGE Amprion ALEGrO Aachen (AAA) explained. A design involving a longsleeve socket provides additional safety. For passages running underneath motorways and ICE train routes, the pipe jacking method was used. Here, drilling lengths were up to 80 m at a depth of up to 8 m. For the cable system installed, a 320-kV cable is used which is inserted into the conduit system. In doing so, the goal is to realise draw-in lengths of up to 1,140 m.
As a system provider, egeplast supplies what ever accessories may be required, e. g. double sockets (long version), transition pieces, electrofusion couplers, end caps, sleeve covers and rental tools (inside debeaders and butt welding machines).