Dissolved gas analysis (DGA) is the study of dissolved gases in insulating fluid such as transformer oil.

Insulating materials within transformers and electrical equipment break down to liberate gases within the unit. The distribution of these gases can be related to the type of electrical fault, and the rate of gas generation can indicate the severity of the fault. The identity of the gases being generated by a particular unit can be very useful information in any preventative maintenance program.

DGA usually consists of three steps: sampling, extraction and analysis.