Chapter 17
Numerical Network-Preserving BCU Method
17.1 INTRODUCTION
Given a power system transient stability model, there exists a corresponding version of the BCU method. There are, however, several ways to define a reduced-state model satisfying static properties (S1) and (S2) and dynamic properties (D1), (D2), and (D3). The reduced-state model proposed in the previous chapter is an effective one, though other reduced-state models exist. In addition, the dynamic property (D2) can be relaxed to (D2), which states that the (reduced-state) controlling unstable equilibrium point (CUEP) of the reduced-state system corresponds to the CUEP of the original system.
The BCU method does not compute the CUEP of the original model directly since the task of computing the exit point of the original model, necessary for the computation of the CUEP, is very difficult and usually requires the time–domain approach. The BCU method first explores the special structure of the underlying stability model so as to define an artificial, reduced-state model that captures all the equilibrium points on the stability boundary of the original power system stability model:
Then CUEP of the original model is computed by computing the CUEP of the following reduced-state model (Eq. 17.2). This can be computed without resorting to the time–domain approach:
A numerical energy function ...
