Nazemi - Electrical Engineering Dept., Amirkabir University of Technology (Tehran Polytechnic) , Tehran, Iran
Allami - Electrical Engineering Dept., Amirkabir University of Technology (Tehran Polytechnic) , Tehran, Iran
Gharehpetian - Electrical Engineering Dept., Amirkabir University of Technology (Tehran Polytechnic) , Tehran, Iran
Shafiee - Electrical Engineering Dept., Amirkabir University of Technology (Tehran Polytechnic) , Tehran, Iran

Different models of transformer windings have been suggested for transient studies. The most of them have been approved by different researchers, but it is shown that the most accurate model is the detailed model which is used by transformer designers. The transformer engineers use this model to predict the surge voltage distribution along the transformer winding, since the utility engineers need to have the black-box (terminal) models of the power transformers. This type of models can be used for insulation coordination of power system in the simulation programs like EMTP. In this paper, based on suggested model reduction technique, a new approach has been presented to derive a terminal model from detailed model. Comparison of simulation results of detailed reduced order and IEEE task force models, shows the accuracy of the presented model.

detailed model, order reduction, grammian, EMTP and TACS