Power System Stability Modes Analysis of Second-Order Resonance Point

The simplest normal form of power system is derived at the point of second-order resonant in simplest normal form theory. To solve the problem that traditional normal form coefficient at the second-order resonance point is strange. Calculation the approximate analytical solution of the power system at the second-order resonance points, fixed participation factors and analysis the formation and changing process of the dominant stability mode. Reveals the change in the dominant mode of formation of stable the physical mechanism, this change is the second-order resonance point caused by the resonance modal. The second-order resonance close to the saddle-node bifurcation is the dominant mode formation of the critical region, the formation of this change caused by the resonance term. Using a power system model verifies the above conclusions.