What faults can transformer oil dissolved gas analysis detect?

DGA can detect partial discharge, low temperature overheating, high temperature overheating, and arcing faults inside a transformer. Hydrogen often relates to partial discharge, methane and ethane to lower temperature thermal faults, ethylene to higher temperature overheating, and acetylene strongly indicates arcing. Carbon monoxide and carbon dioxide indicate paper insulation degradation. DGA also helps detect evolving faults by trending gas generation rates over time, allowing intervention before protection trips or major damage occurs.