Analysis of the inter-area low frequency oscillations in large scale power systems

With the development of bulk interconnected power grids, the problem of inter-area low frequency oscillations becomes more and more outstanding. This paper analyzes the characteristics of the inter-area oscillation in interconnected power system, the machines participating in oscillation can be equivalent to a two-machine system according to their respective inertia center. Based on the equivalent two-machine system, the electromagnetic torque coefficients are deduced, and then on this deduction the mechanism of the inter-area oscillation is explained. At last, some influence factors are proposed to analyze the inter-area low oscillation. Simulation shows that the frequency and damping of the inter-area oscillation are in close relations with inertia constant, tie-line power flow and excitation characteristic.