Stochastic Correlation Analysis of the Transformer Oil Indicators in 330 kV Autotransformers

The paper presents the results of an analysis of the closeness of stochastic relationships between the indicators of transformer oils in 330 kV autotransformers. In contrast to most similar studies, this paper analysed not only linear, but also non-linear relationship between the indicators. The values of pair correlation coefficients, as well as direct and inverse correlation relations for 8 indicators of oil from 49 autotransformers of 330 kV voltage were analysed. The analysis revealed that the most significant stochastic relationship is found between the indicators characterizing oil oxidation. The obtained results will be used for development of models for early diagnosis of transformer oils.