Dissolved Gas Analysis (DGA)

Transformers are vital components in both the transmission and distribution of electrical power. Early detection of incipient faults in transformers is extremely cost effective because it reduces unplanned outages. The most sensitive and reliable technique used for evaluating the health of oil filled electrical equipment is dissolved gas analysis (DGA). Insulating oils under abnormal electrical or thermal stresses break down to liberate small quantities of gases.

The qualitative composition of the breakdown gases is dependent upon the type of fault. By means of dissolved gas analysis (DGA), it is possible to distinguish faults such as partial discharge (corona), overheating and arcing in a great variety of oil-filled equipment. Information obtained from the analysis of gasses dissolved in insulating oils is valuable in a preventative maintenance program. To analyze oil effectively, a number of samples must be taken over a period of time for developing trends. Data from DGA can provide

  • Advance warning of developing faults.
  • A means for conveniently scheduling repairs.
  • Monitor the rate of fault development.