A Novel Numerical Index for Assessing Results of Frequency Response Analysis (FRA): an Experimental Study on Electrical Machines

Abstract: This paper is an effort to evaluate the numerical indices for the assessment of the frequency response analysis (FRA) to provide a deeper understanding of their characteristics. The study introduces the indices in the literature and categorizes them into two groups. The results of an actual FRA experimental setup on an electrical machine are employed to examine the indices from the various aspects. The main features of the indices are extracted, and the better ones in various aspects are marked. Moreover, based on the observations from the experimental studies, a new numerical index for comparing FRA results is proposed in this paper to enhance FRA results assessment and interpretation in both electrical machines and transformers. The advantages of the proposed index are also shown by comparing it with the existing ones.