Rotor configuration impact on generator ventilation needs

Turbogenerators produce a vast portion of the electricity in the world. The cooling and ventilation required to take care of the excessive heat from the generators are costly. Simulations of three 20 MW/20 kV turbogenerators with approximately the same weight but with different stator and rotor configurations have been made. One conventional, one high voltage and one permanent magnet high voltage turbogenerator have been compared. Losses can be cut down considerably by, replacing the electromagnets on the rotor with permanent magnets and switch from an air-cooled stator to a water-cooled high voltage stator. Simulations show that for a 20 MW/20 kV turbogenerator the total losses can be cut down by up to 69% as compared to a conventional generator of the same size.