Transformer winding condition assessment using frequency response analysis and evidential reasoning

The study presents an evidential reasoning (ER) approach to transformer winding assessment based on frequency response analysis (FRA). A conventional FRA assessment process is firstly discussed, where frequency response comparison methods and interpretation features are briefly introduced. Then an FRA assessment process is transferred into a multiple-attribute decision-making (MADM) problem under an ER framework and an introduction to the ER algorithm is given. Subsequently, several examples of transformer winding condition assessment problems are considered using two ER evaluation analysis models, where the potential of the ER approach in combining evidence and dealing with uncertainties is demonstrated. In the case when more than one expert is involved in an FRA assessment process, the developed ER framework can be used to aggregate experts' subjective judgements and produce an overall evaluation of the condition of a transformer winding in a formalised form.