What is the primary limitation of relying solely on key gas ratios in DGA for identifying transformer faults, and what supplemental information is crucial for accurate diagnostics?

The primary limitation of relying solely on key gas ratios in Dissolved Gas Analysis (DGA) for identifying transformer faults is that these ratios can often be ambiguous or inconclusive, particularly in complex fault scenarios or during the early stages of fault development. Key gas ratios, such as the Rogers Ratio or Duval Triangle, are used to interpret the relative concentrations of different gases dissolved in the transformer oil, like hydrogen (H2), methane (CH4), ethane (C2H6), ethylene (C2H4), and acetylene (C2H2). These ratios are intended to indicate the type of fault, such as overheating, partial discharge, or arcing. However, several factors ca....