Ligne à très haute tension, Allemagne

SPIE boosts the performance of an important extra-high voltage transmission line in Germany

Published on 29 October 2024

Ratingen, 29 October 2024 – SPIE, the independent European leader in multi-technical services in the areas of energy and communications, is overseeing the technical planning involved in the renovation of an important extra-high voltage transmission line. This line spans 216 kilometres across the three federal states of Lower Saxony, North Rhine-Westphalia and Hesse. The aim is to increase the power transmission capacity from 2,600 to 4,000 amperes, thereby improving the efficiency of renewable energy transmission. To achieve this, the existing conductors, currently operating at 380,000 volts, will be replaced with HTLS (High Temperature Low Sag) conductors.


 

 

The extra-high voltage line runs from the Landesbergen substation in Lower Saxony through the substations at Grohnde (also in Lower Saxony), Vörden and Würgassen (North Rhine-Westphalia), Sandershausen Ost and Bergshausen, to the Borken substation (all three of which are in Hesse). The expert team from SPIE Germany Switzerland Austria’s High Voltage operational division is planning the reconductoring of 571 pylons along this route. This complex route planning forms the foundation for the subsequent renovation work. A team of specialist engineers, geographic information system (GIS) experts and CAD specialists is calculating the technical requirements for the entire route.

The planning must consider solar temperatures, as well as wind and ice loads, which significantly affect the performance of the high-temperature conductors. Sunlight and electricity cause the conductors to heat up and expand, which results in increased sag. This must be carefully managed to ensure the minimum clearance between the conductor and the ground is maintained at all times. The new HTLS conductors can carry more power, offer greater stability and are rated to withstand temperatures up to 150 °C. By comparison, the older conductors can only handle up to 80 °C. At the required transmission of 4,000 amperes, the new conductors will reach a material-friendly temperature of 135 °C. The structural integrity of the existing pylons also plays a crucial role, as their maximum load capacity must not be exceeded. As part of the renovation, the foundations or lattice structures of certain pylons will require reinforcement. The technical planning is further enhanced by the selection of appropriate insulators, to which the new conductors will be attached.

This demanding project, with its extremely varied route sections, presents several challenges. High levels of coordination are required, as many tasks run in parallel and are closely interconnected. Our expertise and cutting-edge technology allow us to ensure steady progress throughout the project,” says Alexander Behling, who is a project manager in SPIE Germany Switzerland Austria’s High Voltage operational division. State-of-the-art in-house overhead line management software is used for project management, enabling the integration of various geo and factual data. Combining technical and topographical line data with land registry, cadastral and calculation data makes it possible to conduct complex analyses and assessments. “The modernisation of the power grid is essential for the future, as it provides the infrastructure needed for the energy transition. We support our clients with the latest technologies and the highest level of service in expanding the power networks,” notes Burkhard Sager, General Manager of SPIE Germany Switzerland Austria’s High Voltage operational division.

Transmission system operator TenneT, based in Bayreuth, commissioned this project. The company operates an extra-high voltage power grid in Germany and the Netherlands, with over 25,000 kilometres of high-voltage lines and cables. TenneT is driving the green energy transition by modernising and expanding the grid to meet evolving energy demands and support the decarbonisation of the European economy.

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