What limits are used in dissolved gas analysis of transformer oil?

DGA limits are defined by standards such as IEC 60599 and IEEE C57.104. These limits specify concentration thresholds and gas ratios for hydrogen, methane, ethane, ethylene, acetylene, carbon monoxide, and carbon dioxide. Interpretation considers absolute values, rate of change, and gas ratios to classify fault types such as partial discharge, thermal overheating, or arcing.