Dissolved Gas Analysis (DGA)
Transformer overloading, overheating, corona, sparking, and arcing can cause thermal degradation of the oil and paper insulation within the tank. Thermal and electrical faults can accelerate the decomposition of dielectric fluid and solid insulation. Gases generated by this process include hydrogen, methane, ethane, acetylene, carbon monoxide, and carbon dioxide, all which will dissolve in the transformer oil.
The DGA test involves extracting the gases from the oil and injecting it into a gas chromatograph. Gas concentrations are detected using a flame ionization detector and a thermal conductivity detector.
Diagnostic and analysis of the specific proportions of each gas shall help to identify the fault type (thermal conditions involving the oil or the paper, partial discharge, sustained arcing, etc.).
A DGA test study can minimize damage by taking precautionary actions at an early stage.