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Expert perspectives on transformer diagnostics, oil analysis, and asset management from the TriboTech team.
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 changed since 2023: IEC 60567 defers to IEC 60475, two ASTM references withdrawn, one standard now covers 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 · 50 min read
A comprehensive technical whitepaper on transformer oil chemistry, refining processes, international standards, degradation mechanisms, and the green transition toward ester-based insulating fluids.
By Jesper Vinther · 45 min read
How a well-intentioned refining improvement became the power industry's most expensive lesson in oil chemistry. A practitioner's guide to detection, risk assessment, and mitigation.
By Jesper Vinther · 15 min read
New CIGRE research 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.
Put theory into practice with our interactive Duval calculators or try our new unified workflow tool.