Study On Out-Of-Step Oscillation Based On Oscillation Energy Flow

With the scale of interconnected power systems becoming larger and larger, asynchronous oscillation occurs increasingly frequently. Under this circumstance, the identification of out-of-step oscillation along with corresponding separation strategy plays a vital role in preventing catastrophic black outage caused by spreading accidents. During out-of-step oscillation process, electric quantities vary so rapidly and dramatically that traditional methods of oscillation analysis, like small signal analysis, are no longer appropriate in this scenario. In this paper, direct method is used to study the dynamic characteristics of out-of-step oscillation. Based on Dirac structure and port Hamilton, energy structure is constructed and extended to electric power system. Then oscillation energy flow is derived and used in further research on the electrical characteristics' variation rules during out-of-step oscillation process. With analytic functions in the equivalent twogenerator system, the problem of out-of-step oscillation is expounded in terms of oscillation energy flow on the tie line.