What is tribology consultancy?

Tribology consultancy involves expert analysis and advisory services for lubricating oils, grease, transformer oil, and coolants to optimize equipment performance and reliability.

What industries does TriboTech serve?

TriboTech serves TSOs, DSOs, wind farm operators, data centers, solar parks, and industrial operators across Northern Europe.

How quickly can TriboTech respond to emergencies?

TriboTech offers 24/7 emergency support for critical infrastructure with analysis results typically within 48 hours.

Are TriboTech's diagnostic tools free to use?

Yes, all TriboTech diagnostic tools are 100% free to use with no registration required. This includes all 7 Duval Triangles, 5 Pentagon variants, and IEC 60599 ratio analysis. The tools are IEEE C57.104-2019 and IEC 60599:2022 compliant.

What is the Duval Triangle?

The Duval Triangle is a three-gas dissolved gas analysis (DGA) diagnostic developed by Michel Duval for classifying transformer faults from the relative proportions of CH4, C2H4, and C2H2. It is one of the primary tools cited in IEEE C57.104-2019 and IEC 60599:2022.

Triangle 1 vs Triangle 4 vs Triangle 5 — which applies?

Triangle 1 is the primary diagnostic for mineral oil. Triangle 4 (using H2, CH4, C2H6) refines low-temperature faults, and is valid ONLY after Triangle 1 indicates PD, T1, or T2 — never after D1, D2, or T3. Triangle 5 refines thermal faults T2/T3 in mineral oil.

Which Triangle should I use for natural ester (FR3) transformers?

Use Triangle 3 (Duval 2008 alternative-fluid variant) for the primary classification, then Triangle 6 or 7 for low-temperature or thermal refinement. Mineral-oil triangles do not apply to natural ester — the gas chemistry differs.

How does Triangle 2 differ from the other triangles?

Triangle 2 is the OLTC (on-load tap changer) variant. It uses different zone boundaries and includes Zone N for normal arcing patterns seen in tap-changer compartments, which would otherwise misclassify as D1/D2 in the main-tank triangle.

Is this calculator free and does it store my data?

The calculator is free with no registration. All values stay in your browser — TriboTech does not log or transmit input gas concentrations.

Back to Tools

Duval Diagnostic Tools

Name: Duval Triangle Calculator - All 7 Variants
Author: TriboTech ApS

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

ppm

Duval Triangle 1 requires: CH₄, C₂H₄, C₂H₂

Enter all gas values for comprehensive analysis across different tools

Hydrogen (H₂)

ppm

Methane (CH₄)Required

ppm

Acetylene (C₂H₂)Required

ppm

Ethylene (C₂H₄)Required

ppm

Ethane (C₂H₆)

ppm

Carbon Monoxide (CO)

ppm

Carbon Dioxide (CO₂)

ppm

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

TriboTech ApS

Expert Tribology Consultancy

About This Duval Triangle Calculator

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

Duval Diagnostic Tools

1Select Transformer Oil Type

2Select Diagnostic Tool

3Gas Concentrations

Gas Concentrations

About This Duval Triangle Calculator

7 Triangle Variants

CIGRE 2023 Zones

OC-Zone Toggle

Duval Diagnostic Tools

1Select Transformer Oil Type

2Select Diagnostic Tool

3Gas Concentrations

Gas Concentrations

Duval Triangle 1

Zone Descriptions - Mineral Oil

About This Duval Triangle Calculator

7 Triangle Variants

CIGRE 2023 Zones

OC-Zone Toggle

Duval Triangle 1

Zone Descriptions - Mineral Oil