Transient Stability Analysis of Electric Power Systems via Lur'e type Lyapunov Function : Part II

Abstract

It was found in the previous paper that the time derivative of the Lyapunov function used for the transient stability analysis can take a positive value in the case of a system with large transfer conductances ; and it makes the estimation error of the critical fault clearing time large. In this paper, the Lyapunov function is modified in order to remove the defect and fit it to the analysis of the transient stability. Moreover, a new method of determining the critical value of the Lyapunov function is proposed, which is derived from the consideration of the modification. The method uses the value of the potential energy as the critical value when the system gets out of the stability domain. The modified Lyapunov function and the new critical value are applied to a 10-machine system as a numerical example.