QUALITY CONTROL OF TRANSFORMER OIL BY GAS-LIQUID CHROMATOGRAPHY

In oil-filled high-voltage equipment (power transformers, reactors, current and voltage transformers, switches and bushings), transformer oil performs a number of important functions (heat-removing, insulating, arcing, protective, information and diagnostic). With prolonged use in equipment, the oil undergoes oxidation, which leads to a deterioration in its dielectric properties. In order to slow down the process of oil oxidation and extend the life of liquid insulation, an antioxidant additive ionol (2,6-di-tert-butyl-4-methylphenol) is added to it. Using the method of chromato-mass spectrometry, it was found that ionol decomposes during its consumption with the formation of other phenolic-type compounds, which also exhibit antioxidant activity. In addition, the identified degradation products of ionol can serve as indicators of the state of the liquid insulation as a whole. However, the method of chromatomass spectrometry, for certain reasons, is not used in power grid laboratories. Therefore, in this paper, we propose a method for determining the decomposition products of ionol in their joint presence in operating oil, based on the method of gasliquid chromatography with a flame ionization detector. The implementation of this technique does not require significant investments. In addition, new boundary values of ionol have been established, which should be taken into account when planning the addition of ionol to operating oil in order to prevent a sharp deterioration in its insulating properties.