Electro-mechanical efficiency enhancement and refurbishment of the run of river hydro power plant Ybbs-Persenbeug/Danube

The oldest run of river power plant at the Austrian Danube cascade, Ybbs-Persenbeug, was erected from 1954-1959. The original power plant is equipped with six vertical Kaplan turbines, which have been in full operation since 1959. An additional hydroelectric generating set, has been commissioned in 1996. The major drivers of the project Ybbs 2020 are to enhance efficiency and high availability of the power plant. The project taking place from 2012-2020 covers the renewal of the entire electro-mechanical equipment. The entire refurbishment is carried out during full operation of the plant, at the constraint of minimization of generation losses. Out of this, installation works are performed in winter season, during low flow condition of the Danube River. Due to the renewal time of six months per Unit, only one Unit per year gets replaced. The efficiency and the maximum discharge of the turbine are enhanced by replacing the old runner blades and reducing the diameter of the hub. The refurbishment of the slow speed generators covers the renewal of the stator, the rotor poles, the generator circuit breakers and the excitation system. The mirror-inverted transformers of the northern and southern power house, get replaced by symmetric ones. Finally the replacement of the up to 600 m long 220 kV oil cables by modern VPE cables is done. The annual plant production before refurbishment is 1336 GWh/year. The overall increase in production is expected to be at least 60 GWh