Using of Von Mises Criterion to Determine the Failure Proximity and Dynamic Deformation Analysis on Transformers' Windings

Summary

Transformers are essential equipment for electrical systems and they have the largest cost among electrical components. When these devices suffer some kind of failure, their repair or replacement, often require excessive time and cost. Thereby, in this paper, dynamic forces, stresses and displacement of windings in transformers are analysed, using the Finite Element Method, and a support decision-making methodology is presented. The methodology is based on the Von Mises Criterion, which is one of the most employed methodology for determination of failures in ductile materials. The results were achieved by computational simulations, using a 3D transformer model. The results allow to verify the following aspects: failure proximity when a short circuit is applied on the windings; simulation of different values of short circuit to observe failure proximity and aid decision making. Based on the first peak of the asymmetric component, the stress depending on the short circuit current intensity and the stress values can reach a magnitude 40 times larger than the transformer nominal operation, and should not cause a significant failure approach. Dynamic stress behaviour can be used to localize the moment of maximum displacement and points of larger mechanical effort. This methodology can be used to determine the maximum number of short circuit supported for a transformer.

Additional informations

Authors

Gydien, Masson, Ancell, Avdakovic, Breedt, Achilles, Ronnberg, Hermans