Comparison of dissolved gas-in-oil analysis methods using a dissolved gas-in-oil standard

Dissolved gas analysis (DGA) is routinely used to determine the concentrations of gases dissolved in the insulating oil of transformers. These concentrations are used to investigate and diagnose electrical or thermal faults [1]. Such faults cause the transformer oil, pressboard, and other insulating materials to de compose and generate gases, some of which dissolve in the oil. The results of DGA must be accurate if faults are to be diag nosed reliably. Commercial testing laboratories understandably prefer measurements that can be made easily and quickly. In this paper, DGA results from five independent testing lab oratories are compared and discussed. A dissolved gas-in-oil standard with known dissolved gas concentrations was used as the basis of comparison.