Influence of Solid Rotor Steel on Dynamic Response and Losses of Turbo-Generator with Loss of Excitation

The rotor of turbo-generator is made of solid steel, instead of laminated steel, for its high speed rotation. The asynchronous torque resulting from the eddy current in the rotor core plays an important role in the asynchronous operation of turbo-generator after loss of excitation. On the other hand, the rotor loss and temperature rise restrict the operation of turbo-generator. The selection of solid steel is therefore a key factor that affects the operation limit and should be carefully considered in the design of turbo-generators. For a turbogenerator with the rotor core made of different solid steel this paper presents time-stepping finite element calculation of the asynchronous performances and the experimental validation. The influences of different rotor solid steel on the dynamics, saturation and rotor loss of turbo-generator with the loss of field are studied. The losses in different areas of rotor are calculated and compared. The results provide steel manufacturers and generator designers with the theoretic basis for improvement of the asynchronous operating ability of turbo-generator.