A transformer fault leaves a gas signature in its insulating oil long before it leaves a symptom on site. Dissolved gas analysis reads that signature: hydrogen from partial discharge, acetylene from arcing, ethylene from a thermal fault in the winding, carbon monoxide from overheated cellulose. This section covers what each gas means, how the Duval triangle and Rogers ratios turn a gas profile into a diagnosis, where the IEC 60599 limits apply, and how continuous online monitors compare with laboratory sampling in detection window, repeatability and ten-year cost.
Why transformer online monitoring is becoming essential Power transformers serve as the backbone of power transmission and distribution networks, ranking among the most costly, critical, and irreplaceable assets for power utilities, EPC contractors, renewable energy plants, and large industrial facilities.…
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…
