French public power transmission system operator RTE has entrusted Eiffage Énergie Systèmes with replacing steel pylons on the 63,000 volt power line linking Albertville and Venthon, in order to secure the region’s power supply and reinforce the line. This worksite is located on a mountain side in an urbanized area of the Savoie department - a restricted environment that our teams will have to deal with.
In 2020, our specialists rolled out a telecom ground wire on the existing line, between the Albertville and Venthon substations, using a helicopter to organize the roll-out. They also carried out night work across the SNCF rail network, which required special permits and additional protection.
This year, our experts are preparing to replace three old steel pylons with hot-dip galvanized steel pylons on the same stretch. To do this, Eiffage Énergie Systèmes’ design and engineering department will establish a very precise survey of the supports in place (which they will also scan) in order to draw up a 3D plan of each pylon in the absence of an archive.
“The replacement of these three old pylons by the new ones will be carried out in a semi-urban and very steep area that does not facilitate movement. The new galvanized steel tetrapods will have the same design as the current pylons, with the same slope and base width, but they will be more resistant to weathering, water penetration and corrosion”, said business manager Julien Virlouvet, in charge of the project.
Our specialists will use a crane to install the new pylons in the existing foundations. They will thus be able to reproduce the current asymmetry between the upper and lower feet of each pylon to the millimetre. The worksite on the edge of the cliff will be secured with anti-fall protection nets, a handrail and flat surfaces enabling work to be carried out in complete safety, even on a rocky peak. The assembly of the new pylons and preparatory work will take place in June, while the works are scheduled during the summer. The power line will be de-energized for three weeks while our employees secure it, without any impact on the power supply to the area.
© Eiffage Énergie Systèmes