| Summary: | Overheating fault caused by poor contacts of plum blossom contact is one of the typical defects of switchgear and gas insulation combined appliances. The study of current-carrying friction characteristics and remaining life prediction of plum blossom contacts in different gas medium is of great theoretical and applied significance for the accurate evaluation of the health status of this type of equipment. The test samples are processed according to the real plum blossom contact materials and process. The current-carrying tests in air, N2 and SF6 gas medium are carried out by using a self-built current-carrying table, and the contact resistance degradation curves are obtained. The analysis of the surface morphology of the contact shows that the sample surface shows obvious adhesive wear under the effect of large current and mechanical displacement, the gas medium affects the degradation process of the contact by changing the morphology and element composition of the wear region. The contact resistance failure threshold is determined according to the V-T relationship of the contact. The Savitzky-Golay filter is used to smooth the original curves of the contact resistance. The life of plum blossom contacts in three gas medium is predicted by using Wiener degradation model updated by Bayesian. The results show that the model is more accurate than the conventional Wiener model. The remaining life of the plum blossom contact in the air is 9 500 cycles. The life of the plum blossom contact in N2 is 61 300 cycles. The life of the plum blossom contact in SF6 is 32 200 cycles.
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