Evaluation of Power System Stable Region Based on Hopf Bifurcation Theory

Abstract

Power system is a dynamic system, which includes several kinds of nonlinear elements. Transient stability is a typical example originated in the nonlinearity of power swing. On the other hand, the use of nonlinear analysis method based on the Hopf bifurcation theory tells us the existence of limit cycle around an operating point and the stability of limit cycle. In this paper power system global stability formed by an unstable limit cycle, is evaluated. The limit cycle mainly results from the excitation control. Therefore, it is important to consider the effect of flux change in the field winding in addition to the δ-ω variables. This paper presents a method to calculate the correct stability boundary associated with the unstable limit cycle. Some numerical results using a model power system demonstrate the accuracy of method.