How does DGA oil transformer analysis help detect internal transformer faults?

Dissolved Gas Analysis (DGA) measures fault gases generated when insulation is stressed by heat or electrical discharge. Overheating tends to raise gases like ethylene and methane, while arcing produces acetylene. Rising hydrogen can indicate partial discharge or low energy faults. By tracking concentrations and trends, DGA can warn of developing problems before they cause catastrophic failure. Interpreting DGA alongside load history, temperature, and other oil tests helps pinpoint likely fault type and urgency of maintenance action.