Investigation of induction machine contribution to power system oscillations

Incorporation of load dynamics in stability studies is necessary nowadays, especially due to the increased use of induction machines in both consumption and generation. This paper investigates power system small-signal stability, considering induction machines as dynamic elements. Linear coefficients are proposed that are convenient for both quantitative and qualitative single machine-infinite bus studies. These coefficients are expanded into matrices in the case of multimachine systems, where the off-diagonal elements represent the interaction between machines. Modal interaction between induction machines, as well as between induction and synchronous machines, is investigated. It is shown that a large proportion of induction machines in a realistic power system significantly affects the interarea electromechanical mode and, consequently, the power system stabilizer design.