Analysis of facilities for CNR

CNR (Compagnie nationale du Rhône) owns and operates 19 dams, 19 large and 7 small hydroelectric power stations, 1 mini hydroelectric power station and 14 large locks on the Rhône. As the concession holder for the river’s hydroelectricity production (as well as river transport and agricultural uses), the French company decided to carry out a review of all its facilities in the Rhône valley, focusing on the resistance of equipment to short-circuit currents and the selectivity of protection systems.

Commissioned by Amstein & Walthert

As part of the call for tenders, the Swiss company Amstein & Walthert, a specialist in construction technology, brought in HYDRO for its expertise in analysing the high and medium-voltage (HV and MV) protection of hydroelectric facilities (lines, transformers and alternators). HYDRO was subsequently commissioned to survey six facilities:

• Génissiat (Ain)
• Seyssel (Ain)
• Chautagne (Savoie)
• Belley (Ain)
• Brégnier-Cordon (Ain)
• Beauchastel (Ardèche)

The services included modelling the installations to analyse HV and MV protection plans (equipment short-circuit resistance) and load flows.

In this context, HYDRO drew up protection summaries of the current state and analysed each function in detail. This revealed anomalies such as a lack of protection, ineffective settings and undersizing. In a second phase, recommendations and optimisations concerning the selectivity of the electrical protection were proposed.

Operator training

The project concluded with on-site presentations and training of the operators on the existing protection plans (type and role of the various functions) and the potential improvements that could be made in line with our recommendations.

Thanks to the excellent spirit of collaboration with the CNR project team during the analyses and various on-site sessions, this project was conducted under excellent conditions and to the customer’s satisfaction.