Comparisons Between Quantitative FMECA Methods: A Case Study on Power Transformer Risk Assessments

The efficacy of new FMECA methods can be assessed through qualitative comparisons of the failure mode rankings. This approach is suitable for a few failure modes but can become impractical or lead to misleading results for more extensive problems. This fact motivated us to introduce an alternative approach for comparing different FMECA methods based on agreement coefficients, enabling a statistical comparison between rankings generated by independent raters. Despite its relevance, the application of agreement coefficients is limited in the FMECA context. Our proposed approach utilizes Cohen’s kappa coefficient to evaluate the agreement between six FMECA configurations based on a type-2 fuzzy inference system and a reference FMECA ranking. We conducted an FMECA on power transformers to test our approach, identifying fourteen potential failure modes. Results show that, based on the agreement coefficient, our proposed approach proves effective for a statistical comparison of different FMECA methods rather than a qualitative comparison between rankings.