Aged Transformer Oil Analysis Through Laser-Induced Breakdown Spectroscopy

The periodic inspection of power transformers is important to prevent possible failures in power systems. One effective approach is transformer oil analysis. In recent years, the need for a fast, accurate, and in situ method has been increased significantly. This research employs laser-induced breakdown spectroscopy (LIBS) to analyze transformer oil and investigate its aging. For this purpose, the changes in the intensity of molecular emissions (C-2, CN, and OH) and their correlation with aging processes are used. Spectral investigation shows that Cu lines are added to the spectra of aged samples. Temperature and electron density of plasma are calculated. Additionally, the principal component analysis (PCA) method is used to check and compare the overall spectra. Finally, the results of gas chromatography (GC) and acid number (AN) tests are given to confirm the age of the samples.