Abstract: Gas chromatographic analysis is a common technique to detect oilimmersed transformers in operation. By collecting a small amount of transformer oil samples to analyze the gas composition and content in the oil, it can be judged whether there are faults or hidden dangers in the transformer.The coils and cores of oilimmersed transformers are all installed in transformer boxes and immersed in transformer oils, so it is impossible to observe the hidden trouble of transformer directly. The application of gas chromatography to transformer detection can fully solve this problem. In this paper, the gas chromatography was used in practice, and quickly discovered the hidden trouble of the equipment, which provided an effective means to deal with the hidden trouble of the equipment thoroughly and guarantee the stable operation of the equipment.

Key words: gas chromatographic analysis, oil-immersed transformer, fault judgment