Research of the Changes in the Structural Group Composition of Transformer Oil During Operation

The actual issue of the electric power industry is the diagnostics of equipment to timely detection of emerging defects and their prevention. The aim of presented work is the development of a method for monitoring the state of transformer equipment based on the determination of structural-group composition of transformer oil. The goal is achieved by measuring spectra of oil in the near-IR (infrared) region. The method of investigation isapproximation of obtained spectra of transformer oils on the basis of reference compoundsspectra.A new method for determining the structural group composition of oils was proposed. It is distinguished by a significant simplicity and directly related to the characteristics of the molecules in comparison with the existing methods for determining the structural group composition from nomograms.Optical spectra in the near-IR range of fresh and used samples of GK transformer oil in the range of 10250-11750 cm-1were recorded and analyzed. It was shown that during the aging transformer oil fraction of CH2-groups decreases, CH3-groups fraction increases somewhat, CH-groups fraction is significantly increased, thereby confirming the effect of increasing the proportion of aromatics in such systems reducing the amount of cycloalkanes, paraffins are most stable. This fact can be used to develop monitoring systems for power oil-filled transformers. Determination of the structural group composition of the oil and its changes during operation will allow monitoring the oil condition, the technical condition of the transformer and to determine the origin of thermal and discharge defects