Condition assessment of transformer oil using UV-Visible spectroscopy

Transformer plays an important role in both the transmission and distribution system in electrical power system network. During continuous long period of its operation, transformers are mainly subject to huge thermal and electrical stresses, which can cause the degradation of the insulating oil present inside the transformer. The degradation of such insulation leads to catastrophic failure of transformer which further leads to power system network failure. Since there is a great necessity of inspecting the oil time to time, absorption spectroscopy is considered for condition assessment tool because it has the potential to take measurements during operation, which has better measurement ranges for low concentrations. In this work, a novel method used for transformer health assessment is developed based on the characteristic of spectral absorption by adopting ultraviolet absorption technique. The outcome of the absorption of in-service and laboratory aged transformer oil is so significant that absorption increases by observable margin over a wide range of wavelengths. From the obtained results, the sensitivity and reliability of the UV-Visible method in monitoring degradation of oil is analysed and discussed.