By switching to high-temperature conductors, 50Hertz increases the transmission capacity on the first section of an important 380-kV overhead line between Saxony and Thuringia that crosses southern Saxony-Anhalt. Today, near Zeitz and Groitzsch, conductor-pulling works started for the 27-kilometre eastern section of an overarching project that connects the substation of Pulgar, south of Leipzig, and the substation of Vieselbach, near Erfurt. In total, approx. 40 % more current will then be able to flow through this section.
The new overhead conductors are made of a special alloy. These can be operated at temperatures above 100 degrees Celsius instead of the current maximum of 80 degrees Celsius but do not have a much greater sag when the tensile stress is increased accordingly. Only three of the existing towers need to be raised to ensure sufficient ground clearance.
“With high-temperature conductors, we have an additional technology at our disposal to increase the transport capacity of our transmission grid that enables the secure integration of as much electricity from renewable sources as possible into our system. Unfortunately, this additional capacity comes with higher transport losses, so that each use case has to be weighed carefully. For the first section of our line from Pulgar to Vieselbach, we have chosen this technology because the tower systems are still far from reaching the end of their life cycle. In such closely defined cases, replacing the conduc-tors is therefore a sensible solution, both in terms of cost-efficiency as well as with regard to the im-pact on the landscape,” Dr Frank Golletz, 50Hertz’s CTO, explains.
This first building stage concerns the first 50Hertz project that underwent a simplified permit procedure under the German grid expansion acceleration act (Netzausbaubeschleunigungsgesetz or NABEG). The Federal Network Agency (Bundesnetzagentur or BNetzA) waived the initiation of a formal planning approval procedure based on this act as well as the German federal requirements plan act (Bundesbedarfsplangesetz), as it only concerns a minor change to the line. In the other (middle and western) sections of the 105-kilometre overhead line between Geußnitz in southern Saxony-Anhalt and Erfurt-Vieselbach in Thuringia, more extensive measures are required and a planning approval procedure is therefore necessary. These procedures are expected to be finalised in 2022.
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