Comparative studies of prefiring NGH scheme and phase imbalance scheme on stabilizing torsional oscillations

This paper presents the comparative results of using prefiring NGH scheme and phase imbalance method for damping torsional oscillations of a series capacitor compensated power system. The IEEE Second Benchmark Model, system-1, containing a turbine-generator set connected to an infinite bus through a series capacitor compensated network, is employed as a standard system model. The ElectroMagnetic Transients Program (EMTP) is employed to simulate and compare the damping effects respectively provided by the prefiring NGH scheme and phase imbalance method. The simulation results show that the prefiring NGH scheme gives better damping characteristics to the studied system than the phase imbalance scheme