In this work a new fluorescence emission measurement technology was introduced and
experimentally compared with other measurement methods, such as the titration method
and IR spectroscopy, to validate it for the oil oxidation measurement of electrical insulating
oil. The oxidation characteristics of insulating oil were found to be fairly represented by the
titration method and IR spectroscopy, and the results are comparable to a change in the
fluorescence emission ratio that is defined as the shift in fluorescence intensity in the measured wavelength range. The result also shows that by the measurement of fluorescence
emission ratio, it is possible to detect the oxidation of oil relatively earlier than by other
methods. This study suggests that the developed technology can provide sufficient information for evaluating the insulating oil quality, and that the developed FER sensor can
be used as an effective condition monitoring device of electrical insulating oil oxidation.