on-line control strategies; load flow; state estimation
This paper presents an internal decoupled tracking state estimation of a large interconnected power system when part of a system state has to be tracked using the external system equivalent models. The external system models are identified from the real-time internal measurements being processed by the Kalman filtering technique. Those models identified were then embedded into the internal system constant Jacobian models so as to reflect the reaction of the external system arising in response to the internal system conditions. The resulting modified internal system model is then utilized to develop a weighted least square version of the internal decoupled tracking state estimation algorithm. The proposed algorithm has been tested on a 25-bus test system and the results are presented. It is found that the convergence characteristic of the internal decoupled tracking state estimator is the same as that of an overall system tracking state estimator, with a drastic reduction in computation time and memory requirements.