New methods of DGA diagnosis using IEC TC 10 and related databases Part 2: application of relative content of fault gases

Four combustible gases (hydrogen, acetylene, ethylene and methane) generated by internal faults in transformers were selected in this paper to diagnose faults, and two diagnosis methods are proposed. One consists in distinguishing between faults based on the relative percentage of these four gases, and the other in using combinations of the relative percentage of two of these four gases. Accuracy of the proposed diagnosis methods was verified using IEC TC 10 and related databases.