Estimation of severity of simulated mechanical damages in a single isolated transformer winding

Abstract

Transformer windings experience abnormal mechanical forces due to short-circuits occurring in its immediate network neighbourhood. The cumulative strain from these abnormal forces lead to winding damages. Occurrence of damages can be detected with high sensitivity using the well-known frequency response method. The damages most often manifest as a right or left shift of the peak/trough in the frequency response. It is beneficial to the operator looking at these shifts to know extent of severity of a damage, to enable taking a decision whether to continue operation of the transformer or not. Presently, there exists no such assistance. With this motivation, this paper proposes a new index that can effectively capture the severity of damage of any kind and be applicable to all kinds of windings. In this preliminary work, simulation results on a fully coupled ladder network along with practical measurements on a model-coil are presented to demonstrate efficacy of the proposed index to qualitatively capture the severity of a damage. In this preliminary work, damage is simulated as a discrete change in an element of the ladder network or model-coil.