TriboTech ApS
Expert Tribology Consultancy
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Duval Diagnostic Tools
Your inputs stay in your browser. We don't log gas values.
Advanced transformer fault analysis using dissolved gas analysis
1Select Transformer Oil Type
Select Transformer Oil Type
2Select Diagnostic Tool
Choose the appropriate Duval tool for your analysis
3Gas Concentrations
Input the dissolved gas analysis results from your transformer
Load example:
Gas Concentrations
ppmDuval Triangle 1 requires: CH₄, C₂H₄, C₂H₂
Enter all gas values for comprehensive analysis across different tools
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Total Required Gases (CH₄, C₂H₄, C₂H₂)0.0 ppm
Total All Gases0.0 ppm
Selected Configuration:
Mineral OilDuval Triangle 1
About This Duval Triangle Calculator
TriboTech's Duval Triangle tool includes all 7 triangle variants in a single interface, making it the most comprehensive free DGA interpretation tool available online. This tool implements the latest CIGRE 2023 corrections including refined arcing sub-zones (D1-H, D1-P, D2-H, D2-P) and the OC-zone toggle for mineral oil carbonization detection.
- Triangle 1: Primary mineral oil analysis (CH4, C2H4, C2H2)
- Triangle 2: OLTC (On-Load Tap Changer) diagnostics
- Triangles 3 & 3b: Alternative fluids (Silicone, Midel 7131, FR3, Biotemp)
- Triangles 4 & 5: Low-temperature and thermal fault refinement
- Triangles 6 & 7: FR3 natural ester specialized analysis
IEEE C57.104-2019
IEC 60599:2022
CIGRE TB 771
7 Triangle Variants
Complete coverage from primary mineral oil to FR3 natural esters
CIGRE 2023 Zones
D1-H/D1-P and D2-H/D2-P arcing sub-zones with partial discharge distinction
OC-Zone Toggle
Oil carbonization detection for mineral oil transformers
Further reading
Technical Guide
Which Duval Method Should You Use? Triangles, Pentagons and the Right Choice for Your Fluid
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.
Read the article
Technical Guide
Inside Duval Triangle 1 and Pentagon 1 — coordinates, zones, and live diagnostics
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.
Read the article
Technical Guide
How Duval diagrams are constructed: ternary geometry, pentagon centroids, and zone vertices
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.
Read the article
Technical Guide
DGA in Load Tap Changers: Don't Read the Sample Like the Main Tank
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.
Read the article