A SPARSITY-ORIENTED TECHNIQUE FOR POWER-SYSTEM SMALL-SIGNAL STABILITYANALYSIS WITH A PRECONDITION CONJUGATE RESIDUAL METHOD

This paper presents an efficient method for small signal stability ass essment in real-size power systems. Eigenvalue analysis based approach es have been studied to evaluate the stability problem. The convention al methods require calculating all the eigenvalues in evaluating small signal stability. Among them, the QR method is widely-used due to its robustness and high accuracy. However, the method has a drawback in t hat it is not applicable to real-life systems with respect to computat ional time and storage. Recently, the S-matrix method has been develop ed to overcome the problem. The idea of the method is based on mapping the most critical eigenvalue from s-plane to z-plane. As a result, th e method requires calculating only the most critical eigenvalue rather than all the eigenvalues. Although the method is theoretically elegan t, it has a numerical problem. It generates unnecessary fill-in elemen ts which result in increasing computational time since the direct meth od is used in solving a set of linear equations. That becomes more sig nificant with system size. In this paper, an efficient indirect method is developed using a precondition technique. The proposed method has been successfully applied to several systems. The simulation results i ndicated that the proposed method is 30 times and 5 times faster than the QR and the S-matrix methods, respectively, for a 46-unit, 191-bus system.