4. Conclusion
Initiation of oil oxidation in electrical insulating oils is most important to monitor in power transformer equipment, because it indicates that the oil can be expected to abruptly degrade thereafter. In this work, results obtained using a newly developed FER sensor result were compared with the results obtained by other measurement methods to determine whether the FER could be used to provide an effective method to monitor oxidation of electrical insulating oils. It was found that the measured FER parameter could be used to analyze the oil oxidation in a simple and effective manner.