Research on Gas Generation Characteristics and Fault Diagnosis of Typical Defect Discharge Evolution in Transformer Bushings

The oil-impregnated paper bushing is one of the commonly used outgoing line components in power transformers and an essential electrical device in the power system. The progression of micro-defects in oil-impregnated paper bushings into severe discharge can lead to equipment failure or explosions and other accidents. However, research on the development process of internal micro-defects and their diagnostic criteria remains insufficient. Dissolved gases in oil, as key parameters for defect discharge development, play a critical role in identifying defect types. In this study, several common on-site micro-defects were simulated. Through discharge development experiments, the gas generation characteristics of typical defects at different stages were analyzed, and a defect identification method based on gas ratios was proposed, providing both theoretical insights and experimental evidence for fault diagnosis in bushings.