Symptoms (analysis)

The specific symptom of the “Degradation of insulating papers” criticality is related to the presence of non-conforming oil values for the following diagnostic indicators:
Water in oil (IEC 60814)
CO2 – carbon dioxide
CO – carbon monoxide
2FAL – 2furaldehyde and other furan compounds
Particles (IEC 60970)
Gases symptomatic of hot spots (methane, ethane, ethylene)

To these are added diagnostic indicators derived from insulating paper analysis (following any internal inspection and sampling):
Water in papers
Deposited metals (e. g. copper)

There are also co-factors useful to complete the diagnostic framework (resulting from the oil analysis):

Acidity TAN (IEC 62021-1)
Dissipation factor (IEC 60247)
Interfacial tension (ASTM D971, EN 14210)
Additives:Passivators (BTA, Irgamet 39, Irgament 30); oxidation inhibitors (DBPC, DBP)
DBDS (IEC 62697-1)
Dissolved metals (ASTM D 7151)
Oxidation stability (IEC 61125)
Sediments and sludge (Annex C of IEC 60422 Ed. 4-2013
Oil fingerprint


Sea Marconi test reports are compliant (EN ISO/IEC 17025) concerning the indication of measurement uncertainty (except for the aspect that is not a numerical test, and for the ISO particle code).

Through oil analysis,it is thus possible to identify and quantify paper degradation products to evaluate the thermal life consumed.

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