On-Line Damping Torque Estimation and Oscillatory Stability Margin Prediction

This paper discusses the estimation of damping torque of generators in power systems from ambient data to predict proximity to oscillatory instability. A Box-Jenkins model, which is a linear parametric model, is used to accurately estimate damping torque. The results are compared with respect to the theoretical values obtained from the linearized system models and the estimates obtained from an ordinary least square method for the 2-area benchmark system. A 14 000-bus real system is also studied to investigate the effectiveness of the proposed damping torque as a stability index in practice, showing that this index is an effective tool that may be of significant help to operators for preventing stability problems