Expert Tribology Consultancy
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Normalise an in-oil ageing-marker reading (methanol, ethanol, 2-FAL or water) to a 20 °C reference so samples taken at different temperatures can be trended on a common basis — per CIGRE TB 779:2019, Fig 4-10. A trending aid, not a diagnostic.
Enter a concentration and a sampling temperature.
150 µg/kg at 55 °C
90 µg/kg at 60 °C
1.2 mg/kg at 45 °C
CIGRE TB 779:2019 Eq 4-3 defines the temperature-correction factor as Cf_M = [M]²⁰°C / [M]ᵀˢ, so the 20 °C-equivalent is [M]²⁰°C = Cf(T)·[M]measured. Water, methanol, 2-FAL and 2-FOL are read directly from TB 779 Table 6-1 (p.62; a mineral-oil + thermally-upgraded-paper system), linearly interpolated and used verbatim — not re-anchored to 1.0 at 20 °C, because re-anchoring a published table would mean editing it. Ethanol has no Table 6-1 entry and keeps the digitised Fig 4-10 curve; that curve is our own digitisation of the figure rather than a published number, so it is anchored to Cf = 1 at 20 °C exactly, as Eq 4-3 requires. Treat ethanol as indicative and not directly comparable. Polar markers partition into oil as temperature rises, so Cf falls above 20 °C (it scales the hotter reading down). Steepness order: water > methanol > ethanol > 2-FOL > 2-FAL. Per TB 779 §6.4 the 2-FAL correction trend is not yet validated — use it for trending only (the companion DP estimator uses raw, uncorrected 2-FAL, so it is unaffected). Valid 20–100 °C. A temperature-normalisation aid only — there are no normative thresholds, so no condition is inferred; IEC TR 63025:2021 standardises the measurement method, not interpretation.
The tools are calculation tools made available free of charge by TriboTech ApS as part of the professional communication of its engineering consultancy. The tools perform a calculation based on the values entered and the published methods identified. They do not constitute an examination of an asset, a diagnosis, or advice on any specific asset. The tools have no knowledge of the asset's design, history, loading or operating conditions, and a result cannot therefore serve on its own as the basis for a technical or operational decision. A result is an indication, not a diagnosis. Use of the tools does not create a client relationship and does not create an advisory relationship. TriboTech ApS provides advisory services only under a concluded framework agreement, and no advisory liability is assumed for the use of results from the tools outside such an agreement. Any decision taken on the basis of a result — including a decision not to act — is taken by the user on the user's own professional judgement and at the user's own risk. As CIGRE itself puts it: "Actual actions on the equipment are the sole responsibility of engineers in charge of the transformers" (CIGRE Technical Brochure 771, 2019, section C.8, printed page 54). Each tool states which published methods and which editions the calculation is based on. The standard itself is the authoritative source, and a standard may have been revised since the edition a tool uses.
Method implementation — The calculations behind the tools on this site are versioned. When a correction changes the result a tool gives for the same input, that tool's version changes with it. What changed, and when
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