Estimation of Inter-Area and Intra-Area Oscillatory Modes Using System Identification Techniques and Clustering Analysis

Inter- and intra-area oscillations are inherent to large-scale power systems. Identification and analysis of these oscillations are vital for evaluating system stability margins and for determining control actions, aiming to enhance system damping levels. In this paper, a two-stage architecture is developed to facilitate identification of power system inter- and intra-area modes. In the first stage, ringdown responses, obtained from individual system buses, are analyzed using the Matrix Pencil (MP) method and modal estimates are derived. Subsequently, modal estimates are forwarded to a control center where they are grouped, analyzed and combined through clustering techniques to extract system properties, i.e., frequencies and damping factors of inter- and intra-area modes. The proposed approach is tested using simulated data, obtained from the Kundur power system, and found to be very accurate.