Abstract
This paper presents an efficient method for dynamic stability in real-size power systems. Eigenvalue analysis based approaches have been studied to evaluate dynamic stability. The conventional methods require caluculating all the eigenvalue in evaluating dynamic stability. Among them, the QR method is widely-spread due to the high accuracy. However the method has a drawback that the method is not applicable to real-size systems with respect to computational time and storage. Recently, the S matrix method has been developed 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, the method requires caluculating the most critical eigenvalue rather than all the eigenvalue. Although the method is theoretically elegant, it has a numerical problem that it generates unnecessary fill-in elements and results in increasing computational time since the direct method is used in solving a set of linear equations. That becomes more significant with the system size. In this paper, an efficient indirect method is developed using a preconditioning technique. The proposed method has sucessfully applied to a 46 unit-187 bus system. The simulation results indicated that the proposed method is 30t and 5t faster than the QR and the S matrix methods, respectively.
