Improved Swing Equation and Its Properties in

Modeling single-machine (synchronous-generator) infinite-bus (SMIB) systems with what we call the improved swing equations is considered in this paper. The existence and proper- ties of local solutions to the improved swing equations are then examined. Furthermore, the local stability of the SMIB systems is scrutinized. By interpreting the improved swing equations with Taylor expansions, approximate linear time-invariant improved swing equations are derived, with which the dynamics of the SMIB systems can be estimated pointwisely. Comparisons between the improved and conventional swing equations are made through illustrative examples.