ArticleJune 26, 2026

Transformer DGA at CHP: What to Add Beyond Oil Chromatography

Dissolved gas analysis (DGA) is the gold standard for transformer diagnosis but not the only tool. Companion methods at CHP plants: cooling vibration, PD ultrasound, SF₆ and O₂ on adjacent switchgear.

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DGA (dissolved gas analysis) remains the core method for assessing internal transformer condition at CHP plants. It has time lag and blind spots outside the tank — especially cooling failures and switchgear faults.

Companion layers:

  1. Cooling vibration3500/42M / Orbit DCM on oil pumps and fans; weeks ahead of ethylene in DGA.
  2. PD ultrasoundSDT340 on bushings and terminations (partial discharges).
  3. Bay switchgear gasRapidox SF6 6100, fixed SF₆/O₂, Clean Air monitoring.

Sync DGA sample dates with SF₆ tests in one CMMS. Example: rising C₂H₂ and SO₂ in the line breaker → revise the breaker, not only the oil.

Scope: thermal and hydro power; not oil & gas substations.

Request an audit of your transformer diagnostic programme.