The development of the 380 kV network and the increase in the output of the Veytaux power station obliged the owners, both former and current, to reflect on the configuration of the switchgear system and also on ecological restoration. With respect to the geographical situation of the Veytaux site, the installations are located within the Gruyère Pays-d’Enhaut regional nature reserve. As this area is part of the Inventory of Landscapes and Natural Monuments (IMNS) and the Federal Landscape Inventory (IFP), the project had to be submitted to the Nature Conservation organisation for authorisation.
A long-term solution was thus essential, enabling the integration of the high-voltage system into the natural landscape and responding to heightened demands with respect to realisation.
The new system was therefore realised in two successive stages: first of all the GIS-type (gas-insulated) shielded 220 kV system and then the GIS shielded 380 kV system. Two 380/220 kV transformers (150 MVA) were also installed on this site in order to link the different voltage levels and so enable the transition and exchange of energy.
The auxiliary services of the Veytaux system are fed by Romande Energie’s 20 kV network. A new control and protection system in accordance with the standard CEI61850 was implemented across the entire site. Civil engineering works were carried out in order to enable the system’s functioning while minimising interruption to the hydroelectric power station.
The general context of the electricity market and the reclassification to 380 kV of the high-voltage Romanel – Chamoson line, as announced in 2010, required the full modification of the installations of the Veytaux switchgear system in order to guarantee the connection of the power stations to the high-voltage electricity network.
Moreover, the original installations of the former switchgear system were showing certain signs of ageing. The platform’s supporting walls revealed major structural degradation, necessitating sizeable stabilisation work and reinforcement in the medium term.
These relatively restrictive requirements also had to be balanced against the following objectives:
- Limitation or reduction of the impact on various areas linked to the environment
- Optimisation of the installation’s integration into the landscape
- Discovery of a balance between cutting and filling