Voith to upgrade motor-generator for pumped storage plant in Luxembourg

Generator at the pumped storage power plant Vianden in Luxembourg.
Generator at the pumped storage power plant Vianden in Luxembourg.

Voith is to modernize a motor-generator at the Vianden pumped storage power plant in Luxembourg.

The project covers the design, calculation, construction, delivery and assembly of one of the two most powerful machines in the facility. As part of the upgrade, the motor-generator, which was installed in 1976, will be replaced by a new synchronous motor-generator from Voith that will increase the capacity of the generating set by around 7% to 217 MW. The pump turbine remains unchanged, while the new machine will be fitted with a modern starting frequency converter.

“This replaces the direct start-up of the machine via start-up current limiting reactors and a complex damper winding for the generator rotor. With the new starting frequency converter the machine can respond even faster to load fluctuations in the power grid,” explained Stefan Linhart, project manager at Voith Hydro in Germany.

To be able to respond reliably to sudden changes in the power transmission in the grid, the new motor-generator will also be fitted with special vacuum circuit breakers in two generator switch sets – one for each operating mode. This configuration ensures faster switching times in the transition from pump to turbine operation and vice-versa.

Located on the border between Germany and Luxembourg, the Vianden power plant feeds directly into the German electricity grid. It is used as a flexible electricity storage system and to regulate the grid as part of the transition process to renewable energies. The plant is owned by Societé Electrique de l’Our SA, and is marketed and operated by RWE Generation.

The Vianden pumped storage plant went into operation in 1964 and following expansions in 1976 and 2014 currently has a total of 11 generating sets with a generator capacity of 1495 MVA and turbine output of 1290 MW. The entire installed pump output is 1045 MW.