Abstract
This paper proposes a method for determining a parameter to caluculate the most critical eigenvalue in the S-matrix method. The QR method has been widely utilized due to the high efficiency. Since it needs calculating all the eigenvalue to judge if power systems are stable or not, it is not easily applicable to real-sized systems for lack of storage. In recent years, the S-matrix method was developed to make the calculation easier. The method utlizes mapping the eigenvalue from s-plane to z-plane. Thus, the method enables us to focus on the most critical eigenvalue. However, it has a problem that a mapping parameter is determined by trials and errors. This paper presents a guideline for determining the parameter. The method is based on the Gershgorin's theorem that specifies the eigenvalue region. The proposed method has been applied to sample systems such as 3-unit 9-bus and 10-unit 39-bus systems. The effectiveness of the method is demonstrated.
