Power Utility Expands Grid for Renewable Energies

Due to the positive development of the wind farm facilities in Fläming (Brandenburg), the existing grid infrastructure has been expanded since January 2017. A 110 kV cable connection now runs from the Petkus substation to the Schönewalde Süd grid connection point. For this, the grid operator uses the high-temperature resistant protective pipe ege-com^® Macroduct High-T PP and PE.

For the construction of a conduit system for a 110 kV HT 1270 cable from the Petkus substation (UW) to the Schönewalde Süd grid connection point (NVP), the Installation was carried out by Bohlen & Doyen Wiesmoor – using open-cut and trenchless methods. A pipe route of over 25 km was constructed using the open-cut method. The points were connected along the planned route. The route consists of two protective pipe systems, one with a prepared and one with an installed cable system. The cable system is laid in a flat formation with three cables side-by-side, while the empty system is laid in a triangular formation. Areas where open-cut construction is not possible, such as streams, ditches, roads, and river crossings, are traversed using HDD drilling. For the installed cable system, a 110 kV HT 1270 cable from NKT is used, which is pulled into the conduit system. The goal is to achieve pulling lengths of up to 1,800 m.

For open-cut Installation, the ege-com^® Macroduct High-T PP system with a push-fit socket in the dimension 200 x 9.1 mm was used. It is a protective pipe for high and extra-high voltage cables, featuring increased thermal stability to withstand high thermal stresses. Its easy handling allows for economical Installation. “This allowed for Installation rates of up to 300 m in a composite, i.e., 150 rods per day. A positive aspect during construction was the very easy and quick socket assembly, where the factory-set insertion depth marking proved to be very helpful,” explains site manager Paul Eirich. The long socket design offers increased safety. This is particularly advantageous for deflections, such as those occurring in curved sections.

The undercrossings were carried out using the HDD method. Drilling lengths were up to 220 m at a depth of up to 7 m and a drilling radius of approximately 60 m. For the HDD drillings, the ege-com^® Macroduct High-T PP pipes of dimension 225 x 13.4 mm were connected using butt welding. During welding, the internal bead was removed without damage to prevent impact edges for the cable to be pulled in. All necessary accessory components were supplied by egeplast as a system provider – including double push-fit sockets (long version), transition pieces, electrofusion couplers, sliding sleeves, end caps, and socket covers, as well as seamlessly drawn bends. Thanks to productive cooperation and smooth logistics, the project was successfully advanced.