Impact of synchronous machine constants and models on the analysis of torsional dynamics

The authors investigate the impact of synchronous machine parameters and second-order and third-order models on the phenomenon of torsional dynamics. The results were 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 stand-still frequency response (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 electromagnetic transients program (EMTP)