Computer models of internal short circuit and incipient faults in transformers

This article presents the computer models, which simulates the internal short circuit and incipient faults in transformers. To make an accurate diagnostic decision, transformer internal winding faults must be characterized by analyzing quantities of data, which could be generated through computer simulation or field experiments. A finite element method is presented which models internal short circuit faults (H.Wang et al., 2001). Finite element analysis (FEA) techniques are useful to obtain an accurate characterization of the electromagnetic behavior of magnetic components, such as transformers. Finite analysis is applied to calculate the parameters for an equivalent circuit of the transformer with an internal short circuit fault using ANSOFT´s Maxwell Software. Various short circuit and incipient fault scenarios at different degrading insulation levels of the transformer winding insulation were simulated. Graphs of the results will be presented and discussed.