Analyzing the health condition and chemical degradation in field aged transformer insulation oil using spectroscopic techniques

Power transformers are the most essential components of electrical power transmission and distribution networks. During the course of their operation, transformers are subjected to huge electrical and thermal stresses due to which insulation oil inside the transformer is highly degraded. The degradation of insulation oil leads to catastrophic transformer failure which further leads to power system network failure. Hence proper inspection and regular examination of transformer insulation oil is required for smooth and reliable operation of power system. In this research work, insulation oil samples from in-service transformers were taken and analyzed and the results were compared with same grade fresh mineral oil. Absorption spectroscopy techniques e.g. Fourier Transform Infrared Spectroscopy (FTIR) and UV-Visible Spectroscopy were adopted to analyze the insulation oil degradation. The outcome of absorption of aged transformer oil is so significant that absorption increased by observable margin over a wide range of wavelengths. Chemical characterization results highlight that huge amounts of impurities are added to the insulation oil that tend to highly degrade the oil and decrease useful service life of transformer. Hence a proper inspection of the most important part of transformer i.e. insulation oil is required on regular basis.