Vaud Jura: replacement of transformers
As part of the refurbishment of its high-voltage installations at Les Clées power station, Romande Energie commissioned HYDRO to replace the transformers on the three production machines.
Les Clées power station on the Orbe river in Ballaigues was built in 1955. As part of the refurbishment of its high-voltage installations, Romande Energie chose to replace the 40 kV substation and 12 MVA 13/40 kV transformers on the three production machines.
The task entrusted to HYDRO Exploitation proved to be a delicate one. The raw materials market is currently tight and features long materials delivery times and volatile prices. It was therefore decided to opt for a grouped delivery of the three units.
A challenge in terms of logistics and safety
However, given the weight of the equipment (21 tonnes per transformer), the logistics, particularly in respect of storage, were a relatively complex challenge. The premises had to be modified, and the proximity of springs and the Orbe river called for a number of environmental and safety studies.
In the end, this project incorporated the following aspects:
- Disposal and recycling/recovery of the old transformers
- Refurbishment and upgrading of retention pits
- Adaptation of the transformer refrigeration
- Installation of an aerosol fire detection and extinguishing system
- Replacement of the cover plates for the transformer rooms
- Modification of access to the premises to comply with fire standards
- Adaptation of control systems, testing and commissioning
The outcome of this intervention was positive: the installations were commissioned on time and without any major problems thanks to excellent coordination both internally and with all the contractors involved in the project.
