IMPACT OF SYNCHRONOUS MACHINE CONSTANTS AND MODELS ON THE ANALYSIS OF TORSIONAL DYNAMICS

This paper investigates the impact of synchronous machine parameters and second order and third order models on the phenomenon of torsional dynamics. The results were also compared with those obtained from the conventional (2d, 1q) model. For each model, the effect of rotor-field differential leakage flux on the damping of the torsional oscillations is studied. Numerical values of the elements corresponding to each model were obtained based on a parameter fitting process to a set of SSFR test results. An eigen analysis method was used for the studies. The eigen analysis results were verified by digital time domain simulation, using the Electro-Magnetic Transients Program (EMTP). The studies conclude that higher order machine model result in higher net damping for the torsional oscillations. Representation of the rotor-field differential leakage flux in the machine model reduces the torsional damping and widens the torsional range of instability with respect to the level of series compensation.