Abstract: The performance of two types of torsional damper in damping the turbine shaft and blade vibrations induced by power system faults is studied. The damper performance is studied using both the eigenvalue and frequency-scan analyses, and a transient simulation is further executed to verify the post-improved time behaviors. Results show that a damper installed at different locations will provide varied damping augmentations on turbine shafts. For the studied turbine unit with the most serious vibrations taking place at the LP2R-GEN shaft section, the best damper dispositions are at the HP-LP1F and LP1R-LP2F shaft sections for the ID damper and KD damper, respectively. Therefore, a damper may not be installed at the location with the severest vibrations. As for blades, the only approach that can alleviate effectively torque vibrations is to install a KD damper at the LP2R-GEN shaft section. However, this improves the system-frequency response characteristic rather than the damping.