The work has showed some frequency response and
impedance measurements standards for power transformers
(core type), which are mainly determined by the power of the
equipment than by the kind of manufacturer.
The combined use of correlation coefficient and spectrum
deviation may be a useful tool to evaluate and diagnosis power
transformers data related to frequency response and impedance
measurements.
Finally an example of application of the techniques
associated with a criterion was showed using an equipment that
has suffered an accident during its transportation, emphasizing
that it would be impossible to other techniques to diagnostic
the damage in the core bottom of this unit.