Diagnosis of a power transformer: analysis of dissolved gases.

A real blood test from a transformer, the analysis of dissolved gases makes it possible to identify a defect, or its beginnings. A transformer is conventionally immersed in an oil bath in order to ensure the isolation of the live conductive parts of the outer casing of the transformer.
The properties of these oils make it possible both to insulate, but also to dissipate the heat associated with the operation of these high voltage switchgear.

During the life cycle of several decades of a transformer, any defect, however small, chemically creates gases which dissolve in the oil.
By taking a sample of this oil, then an analysis by gas chromatography, it is then possible to obtain an exhaustive overview of the chemical elements present and their proportion. This study, in particular by the analysis of Duval triangles, then makes it possible to identify the origin of the defect, and its degree of importance.