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 Pentagon?

The Duval Pentagon is a five-gas dissolved gas analysis (DGA) diagnostic developed by Michel Duval to classify transformer faults from H2, CH4, C2H6, C2H4, and C2H2 concentrations. It complements the three-gas Duval Triangle and resolves cases where the Triangle is ambiguous.

Pentagon 1 vs Pentagon 2 — which should I use?

Pentagon 1 is the primary diagnostic and classifies faults into PD, D1, D2, T1, T2, T3, or S (stray gassing). Pentagon 2 is a thermal sub-classification used only after Pentagon 1 identifies a thermal fault (T1/T2/T3) — it subdivides into S, O (overheating), C (carbonisation), and T3-H (hot-spot).

What is the CIGRE 2023 correction?

Paulhiac and Duval (CIGRE 2023, ICTRAM06) corrected mathematical errors in the original Pentagon coordinates. The vertex radius was revised from 40 % to 33.33 % of the bounding pentagon, and zone intersection points P′1–P′7 were recomputed. The "Improved" Pentagon variants on this page use the corrected coordinates.

What are arcing sub-zones D1-H, D1-P, D2-H, and D2-P?

These sub-zones distinguish discharges in oil only (suffix H) from discharges involving paper insulation (suffix P). Paper involvement is significantly more dangerous and changes the maintenance response. The sub-zones are available in Pentagon 1 Improved and Unified Pentagon per CIGRE 2023.

Which alternative-fluid pentagons does this tool support?

Pentagon 3 supports natural esters (rapeseed, soybean, sunflower per IEC 62770) and synthetic ester (Midel 7131 per IEC 61099). Pentagon 4 and 4b cover thermal classification for the same fluids; 4b adds D1-P/D2-P paper-involvement sub-zones.

Is this Duval Pentagon calculator free to use?

Yes. The TriboTech Duval Pentagon calculator is free with no registration, no rate limit, and no data retention — input values stay in your browser. The implementation is IEEE C57.104-2019 and CIGRE 2023 compliant.

Back to Tools

Duval Pentagon Dashboard

Name: Duval Pentagon Calculator - 5 Variants with CIGRE 2023
Author: TriboTech ApS

Your inputs stay in your browser. We don't log gas values.

Unified diagnostic dashboard for all Duval Pentagon methods

IEEE Std C57.104-2019 compliant 5-gas analysis for power transformers

Duval Pentagon Dashboard

Unified diagnostic dashboard for all Duval Pentagon methods

IEEE C57.104-2019

Step 1Select Transformer Oil Type

Choose the type of insulating fluid and transformer compartment

Mineral Oil (Main Tank): Traditional mineral-based transformer oil - main tank analysis

Pentagon 1 (IEEE 2019): 9-zone analysis (40% vertex)Pentagon 1 (CIGRE 2023) ★: 9-zone analysis (33.33% vertex)Pentagon 2 (IEEE 2019): 9-zone thermal (40% vertex)Pentagon 2 (CIGRE 2023) ★: 9-zone thermal (33.33% vertex)Unified Pentagon (CIGRE 2023) ★★: 11-zone combined method

Step 2Select Pentagon Tool

Choose the appropriate Pentagon diagnostic tool for your analysis

Step 3Pentagon Analysis

Enter gas concentrations and view diagnostic results

Selected Configuration:

Mineral Oil (Main Tank)Unified Pentagon (CIGRE 2023) ★★

Gas Concentrations

Total Gas

0ppm

H₂

Hydrogen (H₂)

CH₄

Methane (CH₄)

C₂H₂

Acetylene (C₂H₂)

C₂H₄

Ethylene (C₂H₄)

C₂H₆

Ethane (C₂H₆)

Enter gas values to begin analysis

About Pentagon Analysis

The Duval Pentagon methods use 5-gas analysis (H₂, CH₄, C₂H₂, C₂H₄, C₂H₆) to provide comprehensive transformer fault diagnosis. Pentagon 1 identifies the primary fault type, while Pentagon 2 provides detailed sub-classification of thermal faults. These methods are IEEE C57.104-2019 compliant and offer superior accuracy compared to traditional 3-gas triangle methods.

Learn more about Pentagon methods →Contact us for professional analysis

About This Duval Pentagon Calculator

TriboTech's Duval Pentagon dashboard provides all 5 pentagon variants with full alternative fluid support. This is the only free online tool that includes Pentagon 3 with 4 different ester fluid types (Rapeseed, Soybean, Sunflower, Synthetic Ester) plus Pentagon 4/4b for advanced thermal fault analysis.

Pentagon 1: 10-zone mineral oil analysis using 5 gases (H2, CH4, C2H2, C2H4, C2H6)
Pentagon 2: Thermal fault sub-classification (S, O, C, T3-H zones)
Pentagon 3: Alternative fluids with 4 ester variants and 7 zones per fluid
Pentagon 4: Advanced thermal analysis for alternative fluids
Pentagon 4b: Partial discharge sub-zones (D1-P, D2-P) for alternative fluids

What does D1-H, S or C2 mean? Look it up in the fault code library.

IEEE C57.104-2019

IEC 62770

IEC 61099

5 Pentagon Variants

Complete 5-gas DPM method coverage with IEEE-compliant zone geometries

4 Ester Fluid Types

Rapeseed, Soybean, Sunflower natural esters plus Synthetic Ester (Midel 7131)

Thermal Sub-Analysis

Pentagon 2, 4, 4b provide detailed thermal fault classification

Duval Pentagon Dashboard

Duval Pentagon Dashboard

Step 1Select Transformer Oil Type

Step 2Select Pentagon Tool

Pentagon 1 (CIGRE 2023) ★

Pentagon 2 (CIGRE 2023) ★

Unified Pentagon (CIGRE 2023) ★★

Pentagon 1 (IEEE 2019)

Pentagon 2 (IEEE 2019)

Step 3Pentagon Analysis