Adaptive PSS Designed Based on Low-order Linear Model for Large-scale Power System

In this study, an adaptive PSS using data measured at its generator bus is developed. In general, eigenvalues analysis using detailed electric power system model can evaluate the relationship between parameter values of PSS and the stability of the power system. However, it is not practical to evaluate the steady-state stability of large-scale electric power system by this method because detailed information of the actual large power system is not available. In this study, the low-order linear models are utilized for the eigenvalues analysis of the large power system without the detailed model. A generator with a PSS is modeled as the 5^th order model to evaluate the stability. Parameters of the model are identified by least squares method using measured variables at each generator. The 4^th order model is also developed to obtain the dominant oscillation mode of the whole system. PSS parameters are only updated when the eigenvalue detected at the 5^th order model is close enough to the dominant oscillation mode detected at the 4th order model to select the PSS whose parameters should be changed. Dynamic simulation utilizing numerical integration method is carried out for IEEJ WEST 10-machine system model to show the effectiveness of the proposed tuning method.