The Effects of Short Circuits at Medium Voltage Transformers

Abstract

The paper deals with the study of a defect in the 20 kV network at the power substation. In some cases this could lead to dangerous transient phenomena, associated with overvoltages and current circulations. In this paper such a scenario is discussed showing not only the causes and effects, but also some recommendation to avoid possible damages, based on oscillograms recorded by digital protective relays.