A New Scheme for Subsynchronous Resonance Damping of Torsional Oscillations and Transient Torque - Part II, Performance

Part I, a companion paper, presents the concept and suggests practical hardware for a capacitor discharge circuit (named the NGH Scheme) designed to solve SSR problems. Results of analytical studies using hybrid computer simulations indicate that the NGH Scheme is effective in improving both the transient torque and system stability forms of SSR problems. These studies have shown that a combination of the NGH Scheme and generator excitation control would allow series capacitor compensation in a particular 500 kV line in the Salt River Project system to be extended from 15%, the value limited previously by SSR resonance considerations, to 75%.