Dorsalys replaces 80 pylons on a 90,000 volt line in Normandy for RTE

Last April, the Normandy skies witnessed an unusual aerial ballet between the substations at Flers (Orne) and Vaston (Calvados). Two RTE-STH helicopters, a small B3 and a Super Puma (capable of lifting 4 tonnes) replaced 63 of the 80 pylons on a 90 kV line, to upgrade it and secure the RTE network. 

"Aside from the project's spectacular appearance, we orchestrated and coordinated logistics on the ground to support the pylon replacement. The 90 kV line cables were either laid on the ground, or carefully hoisted onto telescopic handler trucks to protect road intersections and the 23 HV line crossings. Then we moved the site (and the 44 telehandlers ) at the same pace as the Super Puma, along the 50 km of line", explained Business Manager Thomas Clep. 

Our line technicians carried out meticulous preparatory work prior to line consignment, pre-assembling the pylons on the ground, fitting protection on the telehandlers, removing the cables on open pulleys with the B3, and securing crossings. "When the Super Puma arrives on the scene, it removes each pylon in two parts (head and base), before bringing in the replacement support, also in two stages. After it has passed, the cables are laid on the new pylons, and we still have to rebuild the joints along the entire line," continued Thomas Clep. 

Eight Dorsalys teams (each with 6 to 8 employees) trained, qualified and authorized for helicopter work were involved in the project.  

Formées, qualifiées et habilitées aux travaux héliportés, huit équipes Dorsalys (comptant 6 à 8 collaborateurs chacune) ont été mobilisées sur ce chantier.