摘要：We provide a review of nonlinear instabilities occurring in networks of rotatory
generators based on our previous papers. The instability phenomena, which we term the
collective instabilities, are of emergent type and observed in networks of synchronous and
induction generators. With both the cases, we provide a unified definition of collective
instabilities using a coupled dynamical system model. The unified definition is expected to
help inquiry to the causes of cascading failure
