What Is Online DGA Monitoring?
Quick answer — Online DGA monitoring continuously samples the dissolved gases in the transformer oil (hydrogen, methane, ethane, ethylene, acetylene, CO, CO2) and reports the values and rate of change in near real time. It gives an early warning of a developing thermal or electrical fault, so you can intervene before a failure — especially valuable on critical or long-lead transformers.
What does online dissolved-gas monitoring (DGA) do?
What it measures
An online monitor extracts the gases from the oil (via a gas-permeable membrane or headspace) and measures them with a sensor or small chromatograph, reporting the key fault gases and trending.
Why it is valuable
It shows the trend and rate of change, rather than a single sample, so a developing fault is caught early. It is especially useful on large transformers that cannot tolerate an outage.
Limitations
It covers fewer gases than a full lab test and needs calibration, but combined with a periodic comprehensive lab DGA it gives strong condition intelligence.
References & standards
- IEC 60599
- IEEE C57.104
Related
Related manufacturers
Prolec GE (GE Vernova) · Prolec GE Waukesha · Hitachi Energy USA · Siemens Energy · Eaton · Virginia Transformer Corp
Related components
Technical content is prepared from engineering references, standards frameworks, manufacturer documentation and industry sources. Contractual or compliance decisions should refer to current official standards. TransformerPath Technical Editorial.
Source transformers for this application
Submit an RFQ or browse manufacturers and components.
Submit an RFQ Get Verified