Total transfer capability computation using small signal stability-based security constrained optimal power flow

Abstract

In an open transmission access environment, the system operating conditions tend to be pushed close to the stability limits. Small signal stability, commonly in the form of low frequency oscillations, is considered to be a crucial factor since it limits the amount of power transfer through interconnected transmission lines under severe disturbances. This paper presents a novel approach to the assessment of the total transfer capability (TTC) using small signal stability-based security constrained optimal power flow (SSS-SCOPF), thereby enhancing small signal sense under a set of credible contingencies while maximizing power transfer. The eigenvalue perturbation method is used to derive the small signal stability constraint included in SSS-SCOPF, which is a linear inequality expressed in terms of the control parameters. In order to reduce the computational burden, Bender's decomposition method is applied to partition the TTC problem with the small signal stability constraint into an iterative two-stage mathematical programming problem. It is then solved by the primal-dual interior point method (PDIPM) in a master-sub problem iteration manner until no constraint violation occurs for each contingency. The effectiveness of the proposed method is clearly validated by comparison with the conventional optimal power flow (OPF) and SCOPF under the same array of transactions, base case, and line outages for the New England 39-bus system. Copyright (C) 2010 John Wiley & Sons, Ltd.