Coordinated design of thyristors controlled braking resistors and Power System Stabilizer for damping electro-mechanical oscillations

This paper presents a new concept for damping electro-mechanical oscillations in large turbo generator. The proposed concept is based on coordination between Power System Stabilizer (PSS) and Thyristor Controlled Braking Resistor (TCBR). This coordination will enhance the stability of the inertial and torsional oscillatory modes. 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 and PSS. The shaft torque´s following a disturbance is computed and analyzed. The obtained results indicate that substantial damping is achieved by the proposed coordination.