Power system state estimation with unified power flow controller

With the flexible of AC transmission systems (FACTS) technique, the power flow in the interconnected power systems can be controlled flexibly. Unified power flow controller (UPFC) is one of the most important components of FACTS. Based on the conventional power system state estimation model, a kind of model for state estimation with UPFC is introduced in this paper, in which power injection model is used and the affect of UPFC on the power flow is transferred to the two nodes of the corresponding transmission line. This method can be integrated to the conventional state estimation program with the consideration of UPFC. The results demonstrate that the model is effective for practical use.