The FRAX 101 Sweep Frequency Response Analyser (SFRA) detects potential mechanical and electrical problems that other methods are unable to detect. Major utilities and service companies have used the FRA method for more than a decade. The measurement is easy to perform and will capture a unique “fingerprint” of the transformer. The measurement is compared to a reference “fingerprint” and gives a direct answer if the mechanical parts of the transformer are unchanged or not. Deviations indicate geometrical and/or electrical changes within the transformer.