Author: Leon Zhang — Power Monitoring and Testing Equipment Team, Baoding Houfeng Trading Co., Ltd., specifying and commissioning transformer DGA monitoring systems for utility and industrial fleetsTechnical review: reviewed by the in-house power monitoring team against IEC 60599:2022 (edition 4.0) and IEEE…
Introduction The Duval Triangle is a graphical diagnostic method used to interpret dissolved gas analysis (DGA) results and identify possible fault types in oil-immersed transformers. The Duval Triangle DGA approach uses the relative concentrations of methane (CH₄), ethylene (C₂H₄), and…
DGA fault detection uses dissolved gas concentrations, gas generation trends, and changes in gas composition to identify developing faults inside oil-filled transformers. Rather than simply indicating whether a fault exists at the moment of measurement, DGA fault detection focuses on…
What gases should be monitored in transformer oil? Transformer DGA monitoring gases commonly include hydrogen (H₂), methane (CH₄), ethane (C₂H₆), ethylene (C₂H₄), acetylene (C₂H₂), carbon monoxide (CO), and carbon dioxide (CO₂). However, the required gas configuration depends on the transformer…
How to choose an online DGA monitoring system Choosing an online DGA monitoring system requires more than comparing the number of gases measured. Power engineers should evaluate the transformer application, gas configuration, detection performance, sampling method, installation requirements, communication interfaces,…
Introduction: why do DGA gases matter in transformer fault diagnosis? Dissolved Gas Analysis (DGA) is the primary predictive maintenance test for oil‑immersed power transformers. When thermal or electrical stress breaks down mineral oil and cellulose paper insulation, characteristic gases dissolve…
DGA results interpretation is the process of evaluating dissolved gas concentrations in transformer oil to identify abnormal gas generation, analyze gas relationships and trends, and determine the possible type and severity of transformer faults. DGA results should not normally be…
Introduction: how can transformer oil reveal internal faults? A Transformer DGA Monitoring System is an online condition-monitoring system that continuously measures dissolved gases in transformer oil to detect developing insulation and thermal faults. An online DGA monitoring system works by…
Online DGA monitoring vs laboratory DGA testing is not a contest between a better method and a worse one. Treating it as one is the fastest way to buy the wrong instrument. The two answer different questions, and most transformer…
By Leon Zhang, Transformer Condition Monitoring Engineer · Published September 9, 2026 · Last updated: October 5, 2026 · 9 min read DGA monitoring for power transformers is the continuous or periodic measurement of dissolved gases in transformer oil to detect developing internal…
