Dissolved Gas Analysis (DGA) Instruments

The Doble Delphi Instruments are dissolved gas analysis monitors that help you track transformer health by providing early warning signs of problems such as overheating, insulation degradation or mechanical movement within the unit. The Doble Delphi provides this valuable information in real time, second by second.

The Doble Delphi is immune to oil surges and vacuums that may affect other sensors; in addition, it contains self-testing diagnostics to monitor its own performance.

The Doble Delphi is available in Standard and Mini models. Each mounts directly to a transformer valve or can be mounted adjacent to the transformer when the need arises. Use the Delphi Mini as part of your comprehensive fleet management program or to monitor smaller transformers in a cost-effective manner.


  • Patented* vacuum resistant membrane prevents failure during oil surges, maintenance or other activities
    * patents include US and Canada
  • Fast response time: getting to 80% of step change in less than 7 minutes means that indications of a problem are given that much sooner and effectively
  • Gas selectivity is high – meaning appropriate measurements rapidly, whether single gas or combined gas
  • Micro pump option – allowing for oil circulation to ensure oil doesn’t go stale and give misleading results (Available in Standard Delphi)
  • Single valve application ensures minimal connection to the transformer
  • Robust, field ready device comes complete with self-test and diagnostics automatically performed on the sensor itself
  • Only requires one transformer valve for operation


  • Single value output
  • High accuracy and repeatability
  • Micro-pump circulation (Available in the Standard Delphi)
  • Vacuum withstand
  • Moisture Detection (Available in the Standard Delphi)
  • Temperature & Sensor Condition Self Diagnostics
  • Continuous Level and trend analysis
  • On-line alarms and indicators
  • Front-panel configuration and PC based Software
  • Communication Options

Interested in learning more?

     The Doble Delphi: Frequently Asked Questions

     Application Notes:


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