Robust stability in power systems with nonlinear loads using generalized Kharitonov's theorem

In this paper a linear model is systematically derived for an n bus m machine system with nonlinear voltage dependent loads at the network buses. The model is versatile and can be used to study different phenomena such as steady-state stability, voltage stability etc. In addition to obtaining the system A matrix, we also obtain a transfer function between load voltages/angles and real/reactive powers at the network buses which is used for robust stability analysis using generalized Kharitonov's theorem. For a given operating point and a given load model, the system A matrix and the eigenvalues can be obtained easily. Eigenvalues for different load models are investigated.