Chapter 14
Network-Reduction BCU Method and Its Theoretical Foundation
14.1 INTRODUCTION
The ability to compute the controlling unstable equilibrium point (UEP) is vital to direct stability analysis. However, the task of computing the exact controlling UEP relative to a given fault is very difficult. The computational challenges and complexities of computing the controlling UEP described in Chapter 12 serve to explain why the majority of existing methods fail. It has been fruitful to develop tailored methods for computing the controlling UEP by exploring special properties as well as some physical and mathematical insights of the underlying power system transient stability model. In this chapter, we will present such a method for computing the controlling UEP: the Boundary of stability region-based Controlling Unstable equilibrium point (BCU) method (Chiang, 1995, 1996; Chiang and Chu, 1995; Chiang et al., 1994).
The BCU method is a systematic method for computing the controlling UEP of large-scale power systems. It first explores the special structure of the underlying model so as to define an artificial, reduced-state model that captures all the equilibrium points on the stability boundary of the original model. It then computes the controlling UEP of the original model by computing the controlling UEP of the reduced-state model, which is much easier to compute than that of the original model. Given a power system stability model with certain properties, there exists a corresponding ...
