Research on Gap Discharge Detection of Multi-metal Conductors in Oil-paper Bushings

Oil-paper insulating bushings are one of the common outgoing line components of power transformers and have experienced multiple faults, causing serious consequences. The defect problem of oil-paper insulating bushings has become one of the main factors affecting the safe operation of power transformers. The defect types of oil-paper insulating bushings are diverse. Currently, there is a lack of experimental research on designing physical models for the discharge defect types of polymetallic guide rods from a practical perspective. The discharge characteristics and gas production features of typical defects of oil-paper insulating bushings are still not perfect. The existing methods for diagnosing casing defects cannot meet the actual requirements for diagnosing casing defects. It is urgent to carry out research on the deterioration process and characteristics of typical casing defects to provide a basis for diagnosing casing defects. From a practical perspective, this paper designs a typical defect solid model of the gap discharge of the multi-metal conduit, builds a defect experimental research platform, and has the functions of online detection of partial discharge and gas chromatography analysis of oil extraction. The discharge development and gas production characteristics of the gap discharge defect of the multi-metal guide rod of the oil-paper insulated conduit are studied. The development characteristics of defect discharge and the gas production law were analyzed and summarized. The research conclusion shows that: With the increase of the withstand pressure time, the discharge phase width increases, and the discharge peak develops from a bimodal feature within half a cycle to a bimodal feature throughout the cycle. The discharge frequency increases, but the discharge quantity shows a trend of first decreasing and then increasing. During the development of discharge defects, the hydrogen content increases more significantly. Although the discharge energy is small and the heating rate is low, it still leads to a slight increase in the temperature in the oil. The research conclusion of this paper has reference value for detecting the development process of gap discharge defects in polymetallic guide rods of oilpaper insulating sleeves.