Electromechanical mode estimation validation using recursive residual whiteness testing

In a power system, it would be valuable to obtain reliable estimates of the electromechanical modes in real time. This requires that the system has been properly modeled. The model becomes inappropriate when there is a mismatch between the assumed model and the true system, e.g. when model parameters are not carefully chosen or when the power system experiences unexpected changes. Therefore, model validation is equally important for it can indicate the validity of the model, and thus, the modal estimation. To carry out model validation, this paper proposes a recursive whiteness testing method that exploits the statistical property of residuals. Compared to the conventional whiteness testing method, the new approach is better at tracking the model behavior in real time. Tests have been performed on simulation models under different conditions.