Study On Low Frequency Oscillations Considering Nonlinear Factors

With the growing scale and complexity of power system, low frequency oscillation of power system becomes a critical problem; conventional small signal stability analysis cannot meet the demand of plan, design and operation of power grid. According to its nonlinear situation, equation of state power system to consider Taylor expansion of secondary items, analyze its impact on low-frequency oscillations; The normal form of vector field is used to analyze the nonlinear interaction of low frequency oscillation, then the second-order analytic solution of the power systems is obtained and linear concept of participation factor is extended by using normal forms transformation; Normal form analysis reveals that N-machine system may have more than N-1 oscillation modes. The correct of the conclusion is testified in terms of the time domain simulation and the Prony analysis method.