What gas is typically an indicator of partial discharge in transformer oil?

Hydrogen is typically the gas that indicates the presence of partial discharge in transformer oil. When partial discharge occurs within transformers, it often leads to the breakdown of the oil and the generation of various gases. Hydrogen is produced as a result of the thermal decomposition of the insulating oil and the subsequent discharge processes.

Margins in transformer operation and environmental factors can influence levels of hydrogen, making it a crucial component in monitoring the health of transformer insulation. Knowing the concentration of hydrogen allows technicians to assess the condition of the transformer and predict potential failures, making it a key indicator in diagnosis and preventative maintenance.

The other gases, while they may appear in some contexts regarding transformer operation, such as methane, carbon dioxide, and ozone, are not as directly associated with the early signs of insulation failure caused by partial discharge as hydrogen is. Hydrogen's rapid formation during such events makes it a primary focus in assessing transformer conditions.