Sensitivity of torsional modes and torques to uncertainty in shaft mechanical parameters

This paper explores the sensitivity of torsional modes and maximum torsional torques to turbine-generator shaft mechanical parameters. The analysis is performed on a typical single machine infinite bus system. Small-signal stability analysis, as well as large-disturbance analysis, are. performed on six rotational mass mechanical system with and without inclusion of saturation of the generator. It is shown that mechanical parameters of the shaft, namely inertia, shaft spring constant. internal shaft damping, and external damping, can significantly influence damping and frequency of torsional modes, mode shapes, and maximum torsional torques.