Subsynchronous Resonance and Torsional Stresses in Turbine-Generator Shafts

A brief introduction to the phenomenon of sustained oscillation of a power system at subsynchronous frequencies is presented. Such oscillations result from the application of capacitors used for series compensation of transmission lines. A state-space model is employed to represent the action of subsynchronous armature currents on turbine- generator shaft torsional vibrations. A digital simulation program for the analysis of turbine generator shaft characteristics based on the state-space model is outlined. Two examples based on typical system parameters are given.