Improvements to a Model of Pole-Mounted Distribution Transformers for Electromagnetic Transient Studies

Abstract

The authors have previously proposed a simulation model of pole-mounted distribution transformers for electromagnetic transient calculations and validated it by comparisons between calculated and laboratory-test results. However, we recently found that the previously-proposed model gives inaccurate results for a specific type of transformers. In this paper, we make clear that the error comes from the fact that the skin effect of the secondary windings is neglected, and an improved model taking the skin effect into account is proposed. The improved model is validated by comparing simulation and laboratory-test results of surge transfer from the primary to the secondary winding and also from the secondary to the primary winding. Furthermore, the model is used in a practical lightning-surge simulation, and the result is shown to be accurate in comparison with corresponding field-test result.