Damping Torsional Oscillations Using Thyristor Controlled Braking Resistors

Abstract

This paper presents a new method for controlling a dynamic braking resistor in power system. It allows a Thyristor Controlled Braking Resistor (TCBR) to effectively damp inertial and torsional oscillations in a large turbo-generator. 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 model for the TCBR is developed. The pole placement technique is used to design the firing angle control system. The shaft torque's following a three-phase fault is computed and analyzed. The obtained results indicate that substantial damping is achieved with a relatively small power rating resistor bank.