Nonlinear oscillations caused by periodic disturbance between inter-area power systems

Understanding the mechanism of inter-area oscillation is an important problem in power system stability research. In this paper, by introducing periodic disturbance, we propose a new mechanism to model inter-area oscillation caused, which promises new direction in this field. As a proof of our idea, a two-machine equivalent model based representation of two interconnected power systems was used. Chaos and bifurcation phenomena have been detected in the system by using a special Poincare section method that considers long-term characteristics of the sampled signal. Based on simulation study of the proposed model, inter-area oscillation evolving from period doubling bifurcation to chaos can be unfolded as the disturbance parameter increases. Our simulation results show three oscillation patterns; those are intermittent oscillation, transient chaos and chaotic oscillation. These results can give new ideas to interpret abnormal oscillating phenomena that happen in real power systems.