The 220 kV open-air switchgear system in Veytaux in the canton of Vaud, a few kilometres south-east of Montreux, is already 40 years old – high time for comprehensive renovations. The fact that the pumped storage power plant of Forces Motrices Hongrin-Léman SA (FMHL) is also currently being extended was an additional argument for carrying out the renewal work. The substation in Veytaux serves to connect the power plant to the high-voltage grid – and thus ensures that the electricity produced can be used safely and flexibly.
The substation project is being managed by Swissgrid in close coordination with Alpiq and FMHL. Alpiq EnerTrans AG has played a crucial role in the construction work. In a first phase, the existing 220 kV open-air switchgear system was replaced with a new 220 kV system, insulated with the protective gas SF6 (GIS) – Alpiq EnerTrans AG constructed a building up to the GIS section as well as the control and safety cabinet. The renewed 220 kV sections became operational in summer 2013, after a year of construction work.
100-tonne transformers on a steep mountain road
In a second phase, which began in autumn 2013, a new 380 kV system (GIS) is being created and two 380/220 kV 150 MVA transformers are being installed. In addition, a new surveillance and control system for the entire substation is being constructed. The system is scheduled to be operational by 2015. The greatest challenge posed by this construction phase is to transport two transformers, each weighing 100 tonnes, up a steep road to the elevated location.
A further challenge throughout the whole project is the stipulation that electricity production must be maintained and that there is scope for only a minimum of scheduled interruptions. Moreover, special attention is being paid to environmental compatibility: all the work was developed with the help of environmental experts and will be implemented in such a way that the systems can be integrated without significantly disturbing the landscape.