Specifics of the Short-Circuit Behavior of Concentrically-Wound Transformers and Autotransformers

The transformers and autotransformers in distribution networks have to withstand the short circuit and this paper deals with the influence of the type of fault and the position of the windings with respect to the magnetic cores. A review of the internal configurations of transformers and an analysis of the fluxes and currents according to the pre-or post-established short circuit, leads to an estimate of the highest stressing arrangements and operation conditions. Tests performed in a high power laboratory confirm the analysis and show the actual currents through the transformer.