Accurate Modeling of Core-Type Distribution Transformers for Electromagnetic Transient Studies

This paper proposes a model of core-type distribution transformers for electromagnetic transient studies. The model accurately reproduces not only the impedance characteristics seen from each terminal of a core-type distribution transformer but also the surge-transfer characteristics between the primary and secondary sides in a wide range of frequency. Because of this capability, the proposed model enables the accurate evaluation of overvoltages on distribution lines including consumer-side overvoltages. A 10 kVA transformer is modeled, and transient-simulation results agree well with laboratory-test ones.