As part of the SuedOstLink project, Kleihues Betonbauteile GmbH & Co. KG is developing and supplying reinforced concrete precast components specially designed for this application from its plant in Sennfeld. The manholes are used for the underground connection of individual cable sections of the planned high-voltage direct current transmission line (HVDC).
The SuedOstLink is intended for the transport of renewable energy – in particular wind power from northern and eastern Germany – to the southern regions of the country. The approximately 540 km long route connects Wolmirstedt in Saxony-Anhalt with Bavaria. The project is intended to strengthen security of supply and further reduce the share of fossil fuels. The line will be laid mainly underground and represents a significant infrastructural contribution to the conversion of the electricity grid to greater climate neutrality.
An important section is component D3b, which runs from the A92 motorway (Munich–Deggendorf) to the Isar substation in the district of Landshut. This section primarily passes through the municipalities of Essenbach and Niederaichbach and forms the end section of the entire route. Here, two converter stations and connecting lines feed up to 4 GW of transmission capacity into the existing power grid. The section covers approximately 2 km and integrates the powerful converter stations with the local grid.
Use of prefabricated concrete elements
The joint pits were made from individual reinforced concrete elements to ensure the safe splicing and connection of the high-voltage cables. These provide a protected, controlled working space in which cables can be electrically and mechanically connected, insulated and shielded under precisely controlled conditions. The prefabrication of the concrete elements allows for quick and precise installation on site and reduces the risks posed by external influences, such as water ingress. The components include openings for cable protection pipes, mounting options for joint supports and integrated buoyancy controls. For flood protection, two-metre-high protection systems were also installed on the wall crowns of the pits.
The individual concrete elements, weighing up to 35 tonnes, were installed by a specialised installation team using a mobile crane. Once the cable connection has been completed and the flood protection removed, the pits will be filled in and the surface recultivated. This will allow the land to continue to be used for agricultural purposes after completion.
The main line of the SuedOstLink (project 5) is scheduled to be connected to the power grid in 2027. The extension (project 5a) is scheduled to be fully operational by 2030.
