Small‐Signal Stability

This chapter considers linearized analysis of multimachine power systems that is necessary for the study of both steady‐state and voltage stability. It discusses the effect of different types of loading on the steady‐state stability for the multimachine case and Hopf bifurcation in the context of voltage collapse. A comprehensive dynamic model is developed to study both low‐frequency oscillations and voltage stability using a two‐axis model with IEEE‐Type I exciter, as well as the flux‐decay model with a high‐gain fast exciter. The chapter also discusses the electromechanical oscillations and their damping, as well as dynamic voltage stability. The electromechanical oscillation is of two types: local mode, typically in the 1 to 3‐Hz range between a remotely located power station and the rest of the system; and inter‐area oscillations in the range of less than 1 Hz.