Installations in operation:
more than 40 hydroelectric facilities

our core activities

innovative solutions

Central workshops:
a special know-how

various services

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the mountains give us their water...

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un savoir faire


Leteygeon SA: inspection of the penstock

Inspection of the small diameter penstocks is often a challenge, specifically due to the logistical and safety constraints. We inspected the Leteygeon penstock (ND 660 mm), which was commissioned in 1977, at the end of 2016. We had to find solutions to be able to perform an inspection of 100% of the penstock.

Our mandate included examination of the interior corrosion protection of the Leteygeon penstock, which is 1,330 metres long, from the forbay tank to the power plant.

Given the small diameter of this pipe, the inspection was mostly carried out using a robot equipped with a camera. The video images were analysed in real time to supply live information to our client, Energie Sion Regions (ESR). Some sections were inspected by our specialists on ropes to measure the thickness of the corrosion protection and to carry out a more precise survey of the condition of the pipe.

Inspecting the pipes requires a high degree of logistics to ensure the safety of the inspection staff. HYDRO Exploitation implemented a specific standard to meet the current regulations for this type of work.

The inspection took 3 days in total. Thanks to analysis of video data in real time, and the inspection performed by the specialists, it was possible rewater the penstock immediately after completion of the inspection, much to the satisfaction of our client who received an efficient and perfectly coordinated service.


Safety is key

Our technical standards determine all of the safety aspects which are associated with such an inspection, in accordance with the legislation (OTConst. Art. 83 [Swiss Construction Decree]) and in a very precise way. The material used guarantees the safety of the people who are in the pipe. Each inspection requires the participation of a minimum of 4 people with clearly defined roles: Only our specialists who have completed a specific training programme can perform this type of work.

Located in the Valais Central area, right in the centre of the Hérens valley, the Leteygeon SA development collects water from the Dixence River and its tributaries located downstream of the Grande Dixence dam.



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HYDRO Exploitation SA
Rue des Creusets 41
CP 750 - CH-1951 Sion
T +41 (0) 27 328 44 11
F +41 (0) 27 328 44 12
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