Transformer Oil Sampling & Analysis

The single most informative diagnostic test

Dissolved Gas Analysis (DGA) is widely accepted as the most reliable tool for the earliest detection of incipient faults in fluid filled electrical apparatus. Under normal operating conditions very little decomposition of the dielectric fluid occurs. However, when a thermal or electrical fault develops, dielectric fluid and solid insulation will partially decompose. Analysis of the quantity of each of the fault gases present in the fluid will identify fault processes such as corona, sparking, overheating and arcing.

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InsuLogix® H/M

Hydrogen/Moisture Monitor

Weidmann’s InsuLogix® H incorporates patented micro-chip based technology using nickel/palladium alloy to measure hydrogen concentration in the transformer oil. An advanced proprietary coating that protects the sensor allows it to directly contact the oil without the need for membranes or filters and enables it to measure hydrogen in both oil and gas phases.  The InsuLogix® H is also available with an optional moisture sensor (H/M) which can also be easily added later in the field.

The InsuLogix® H and HM easily install in the transformer drain valve or other availalble fittings making retro-fit easy and a very cost-effective replacement option for old, obsolete or damaged gas monitors in need of repair or replacement.

Data sheet


  • Low cost and maintenance free solution for hydrogen monitoring in small and large transformers
  • The moisture sensor is optional and can be added later if needed
  • Available in oil or in gas phase versions
  • Has all data recording and communication features as other more expensive and complex gas monitors
  • No moving parts, no membranes, no filters, no consumables
  • Easy to calibrate against a recent DGA reading
  • Easy to install
  • Is compliant with all standards (IEC and IEEE) for instrumentation operating in substation environment
  • Interfaces with Weidmann InsuLogix® VAULT transformer monitor