Transient Energy of an Individual Machine PART I: Stability Characterization

The individual-machine-equal-area-criterion method already shows potential in the transient stability assessment of multimachine systems. This two-paper series systematically analyzes the transient characteristics of the system trajectory from a genuine individual-machine transient energy perspective. In the first paper, the stability property that characterizes a critical machine is investigated by defining the residual kinetic energy, which only occurs at the maximum individual-machine potential energy point. We indicate that the transient energy conversion inside a critical machine can delineate the trajectory stability of the machine. In this way, the mapping between individual-machine kinetic energy and individual-machine trajectory can hence be established. Simulation results show that the individual-machine transient energy describes the system trajectory more precisely than the superimposed global transient energy in terms of transient stability analysis, and we also demonstrate that the conjecture in early individual-machine studies might fail in special simulation cases.