Visualization of stable manifolds and multidimensional surfaces in the analysis of power system dynamics

In this paper we consider the visualization of the behavior of high-dimensional dynamical systems by computing the approximated stable manifolds around fixed points using the normal form technique and the energy function method, respectively. By using an effective graphic package called XGobi, we show the high-dimensional invariant manifolds of fixed points of the dynamical system obtained in two different ways, i.e., the normal form method and the energy function method. XGobi allows us to compare different approximations of the invariant manifolds in all dimensions of the system in the same picture, and to analyze the behavior of actual system trajectories in the neighborhood of the fixed point. By viewing in all dimensions, global structural characteristics of the system can be easily detected.