An iterative sequential observer for estimating the transient states of a power system

This paper presents an iterative sequential observer which enables us to estimate the transient state of power system with high accuracy. This observer attempts to reduce the effect of both the dynamic non-linearity and the measurement nonlinearity. The latter is reduced by modifying the estimates iteratively and the former by discretizing the dynamic equation at every short interval of time. Furthermore an observer gain is introduced which is easily and sequentially evaluated in a similar way as Kalman filter. Simulation results, in which the observer is applied to the system of one machine infinite bus, indicate that the state is estimated successfully even in the cases of less available measurements and there is a capability of a real-time estimation using an on-line computer.