Damping torsional oscillations in large turbo-generators using Thyristor Controlled Braking Resistors

This paper presents a method for damping torsional oscillations in large turbo generator using thyristor controlled braking resistor (TCBR). The study is performed on system-1 of the second IEEE benchmark for simulation of sub-synchronous oscillations, using eigenvalue analysis and verified by detailed digital simulation. A dynamic fundamental frequency model for TCBR is developed. The pole placement technique is used to design the control system of TCBR. The shaft torques following a disturbance is computed and analyzed. The obtained results indicate that substantial damping is achieved not only for the torsional oscillatory modes but also for the inertial mode by using the proposed control system.