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Expert perspectives on transformer diagnostics, oil analysis, and asset management from the TriboTech team.
By Jesper Vinther · 12 min read
Two insulating-fluid families gained a new DGA interpretation standard in twelve months. What IEC 63585:2026 and IEEE C57.146-2025 changed, and what disagrees.
By Jesper Vinther · 7 min read
Insulating-fluid standards publish limits for three lifecycle states, not one. Quote a delivery spec at service oil and the verdict can flip either way.
By Jesper Vinther · 8 min read
There is no single Duval method. Which triangle or pentagon to use is decided by fluid, then equipment, then the question you are answering — a practical selection guide.
By Jesper Vinther · 8 min read
Two labs can report different ISO 4406 codes on the same oil and both be right. Here is why the particle counting method is part of the number — and how to match method to fluid.
By Jesper Vinther · 6 min read
Can dissolved gas analysis be read through Gibbs free energy or a fault-energy index? Here is what the method is, where it came from, and why it is not our field diagnostic.
By Jesper Vinther · 8 min read
A clean post-treatment result can mislead. Regeneration brings acidity, IFT and DDF back toward new-oil levels — but it doesn't dry the paper, doesn't restore the antioxidants, and doesn't necessarily remove corrosive sulphur. How an asset manager commissions and verifies the work.
By Jesper Vinther · 11 min read
A high water result or a depressed breakdown voltage raises the drying question. Here is how to decide whether your transformer needs drying — and the honest limit of what drying can restore.
By Jesper Vinther · 8 min read
ICP is the workhorse of oil elemental analysis, but it only measures dissolved metal. Here is what a low iron number does and does not prove — and why grease needs digestion first.
By Jesper Vinther · 9 min read
An oil sample's dissipation factor (DDF/tan δ) is measured at 90 °C on a liquid specimen; the field tan delta is measured at 20 °C on the whole installed insulation. Two specimens, two questions — and no conversion between them.
By Jesper Vinther · 11 min read
The same transformer oil gives systematically different kV depending on the test method and electrode geometry. That is why limit tables are method-specific, and why a BDV number with no method and electrode gap cannot be interpreted.
By Jesper Vinther · 15 min read
ppm water is ambiguous across temperature and fluid type. Relative saturation (%RS) is the unit that tracks dielectric risk — and the one that lets a mixed mineral/ester fleet be ranked on a single scale.
By Jesper Vinther · 11 min read
More than 95 % of a transformer's water lives in the paper, not the oil. The ppm you measure is a temperature-sensitive window — and how big that window is depends on the fluid. The partitioning story behind the ester advantage, with the caveats baked in.
By Jesper Vinther · 10 min read
Gear oil additive monitoring: what ICP, voltammetry and the functional tests each see — and the elemental-plus-functional spine a CLP gear-oil programme is built on.
By Jesper Vinther · 11 min read
On ZDDP hydraulic oils, voltammetric additive monitoring and a confirmed particle count are the leading end-of-life signals — never an automatic counter alone.
By Jesper Vinther · 11 min read
How RULER linear sweep voltammetry measures antioxidant depletion in industrial oils — the ASTM D6971/D6810/D7590 family, the 25 % RUL alarm, and what LSV cannot see.
By Jesper Vinther · 8 min read
The EU deadline for removing PCB-contaminated transformers passed on 31 December 2025. What 50 mg/kg means, Method A vs B under EN 12766-2, and what to do now.
By Jesper Vinther · 4 min read
Silicone transformer oil is not a PFAS, and neither is any mainstream insulating fluid. One structural test — the carbon–fluorine bond — settles it, and points to where the real PFAS risk at a transformer site actually sits.
By Jesper Vinther · 12 min read
In a non-vacuum load tap changer, acetylene and hydrogen are the normal signature of the device doing its job — not a fault. Here is why applying main-tank DGA frameworks to LTC oil raises false alarms, and how to interpret an LTC sample properly.
By Jesper Vinther · 17 min read
Viscosity, ISO VG and the Viscosity Index explained for engineers and buyers: how viscosity is measured, why VI is a design variable rather than a quality score, and how to read both with their measurement uncertainty.
By Jesper Vinther · 15 min read
Fire point decides whether a transformer fluid is legally less-flammable. What it measures, how it moves in service, and when to monitor it on esters.
By Jesper Vinther · 12 min read
Oil sampling standards moved since 2023: IEC 60567 defers to IEC 60475, ASTM D3613 absorbed, D6871 reinstated, one standard spans four fluids. Check your spec.
By Jesper Vinther · 14 min read
The geometry behind the two most-used graphical DGA methods — barycentric projection for Triangle 1 and an area-weighted polygon centroid for Pentagon 1. Step-by-step derivations, worked examples, and the deliberate asymmetry in how the zones are defined.
By Jesper Vinther · 9 min read
Three regulatory trajectories — PCB, the revised Water Framework Directive, and CSRD — are converging on transformer owners. Here is what to document now, what to prepare before 2028, and how the rules actually read on the page.
By Jesper Vinther · 11 min read
How the two most-used graphical DGA methods actually work. Step-by-step ternary and pentagon arithmetic, the zone boundaries that came from inspected transformer cases, and when each diagram earns its place on a real diagnosis.
By Jesper Vinther · 11 min read
Five millilitres of headspace in a rigid, partly filled sample bottle strips 49 % of the hydrogen out of a transformer oil sample by Henry-Ostwald partitioning. Why correct sampling is a measurement, not a packaging detail — and where consulting judgment refines the standard's conservative numbers in the field.
By Jesper Vinther · 18 min read
Why IFT deserves routine status — and what the 2024/2025 IEC updates change for mineral oil, ester, and GTL diagnostics. A deep technical guide covering measurement methods, standards evolution, and practical maintenance implications.
By Jesper Vinther · 24 min read
A technical whitepaper on transformer oil chemistry, refining, international standards, additives, degradation mechanisms and ester-based alternatives to mineral oil.
By Jesper Vinther · 45 min read
How a refining shift and an antioxidant additive led to a wave of copper-sulphide transformer failures. A practitioner's guide to detection, risk assessment, and mitigation.
By Jesper Vinther · 15 min read
Field evidence reported to a CIGRE working group challenges decades-old assumptions about transformer paper insulation aging. Learn why a DP value of 200 may not be the death sentence you think it is.
By Jesper Vinther · 13 min read
Learn how to integrate IEC 60599, IEEE C57.104, and CIGRE TB 771 into a unified DGA interpretation workflow. Master the triage, quick check, and deep diagnosis methodology used by senior diagnosticians.
By Jesper Vinther · 10 min read
A practical introduction to insulating liquid analysis for asset managers and engineers. Learn how DGA, water content, acidity, dielectric strength, DDF, and interfacial tension reveal your transformer's health.
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