Parameter estimation of a synchronous generator model under unbalanced operating conditions

This paper proposes a new method to estimate parameters of a synchronous generator using measurements taken under unbalanced operating conditions. The new method is based on a combination of the application of the Unscented Kalman Filter (UKF) and Trajectory Sensitivity techniques. The method adopts a three-phase model for the synchronous generator that is typically available in EMT-based commercial software and evaluates the sensitivity of the response to changes in the model parameters, in order to determine if it is possible to estimate a certain parameter based on a particular measured output. This enables the user to choose the best output to estimate the parameter of interest, which is important when the only available measurements are responses to small disturbances. After that, a UKF technique is applied to the three-phase model in 0dq coordinates and, differently from other approaches in the literature, the zero-sequence circuit is taken into account to enable the estimation under unbalanced operating conditions, which is the main contribution of the paper. The results showcase the efficiency of the proposed method even in the case where the available measurements are taken from highly unbalanced conditions.