Application of Improved Large Scale Detailed Model of Transformer for Transients Studies

In this paper, frequency response analysis (FRA) of transformer based on the detailed model of the transformer windings, is investigated. The determination of the detailed model parameters, which can be considered as a large scale model, is a complex task. To overcome this problem, a heuristic method is presented in this paper. This method is applied to a large scale detailed model with nineteen sections.The state equation model is used, to extract the transfer function of the large scale detail model of the transformer. In this paper, all parameters of the model are assumed to be frequency dependent. Also, a new improved detailed model is presented. It is shown that this model can represent the transient behavior of the transformer winding better than the well-known detailed model. In the laboratory, all new ideas presented in this paper, are applied to a 20/0.4-kV and 1600-kVA transformer. The comparison of simulation and measurement results show the privilege of the improved detailed model in comparison with the conventional ones.