Three Gorges/China, Stator Frame with a diameter of 21.42 m in the São Paulo/Brazil workshop. The biggest generator ever built.
Generators
Since the very early beginning Voith Siemens Hydro Power Generation has been supplying the world's largest and most powerful units in performance and size, every time setting new world records. Voith Siemens Hydro Power Generation has rich references in air cooled machines as well as in hydro generators with directly water-cooled windings such as the world’s largest and most powerful units for Itaipu (Brazil / Paraguay) with 823,6 MVA and Three Gorges (China) with 840 MVA as well as the world’s largest and most powerful air-cooled units for Guri II (Venezuela) with 805 MVA and Grand Coulee II (USA) with 672 MVA. All Voith Siemens Hydro Power Generation generators are designed and manufactured with the latest state of art including the use of Vacuum Pressure Impregnation (VPI) technology for the stator bars. Rated voltages up to 23 kV are part of our standard production.
The following design criteria influence the main generator dimensions:
The specified output can be produced by the dimensions within the allowable limit of the temperature rise of coil and core.
The required moment of inertia has to be provided within the given stator bore dimensions.
The mechanical stress incurred by the rotating parts at the run-away speed can be designed within the maximum allowable stresses of the specific material.
A safe margin is provided between the first critical speed and the unit’s run-away speed. Shorter lengths and lighter rotor weights help to realize this margin.
In case of air-cooling, a shorter core length and a larger diameter are better for uniform cooling along the entire core length.
Pumped storage station, Stator Frame, Raccoon Mountain, USA.
