直流开断工况下金属氧化压敏电阻冲击老化及失效特性研究

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中图分类号：TM51 文献标志码：A

Abstract： To investigate the aging and failure characteristics of metal oxide varistors （MOVs） during DC interruption， this study establishes an experimental platform for MOV aging and failure. The changes in threshold voltage，leakage current，nonlinear coeficient，and residual voltage of MOVs under repeated pulse actions are examined. The finding reveals that the threshold voltage initially increases and then decreases with the increase in the number of impacts，with an overall change of no more than 1% . The leakage current I75% shows close to linear growth with an increasing number of impacts，while the nonlinear coeficient α gradually decreases as the number of impacts increases，with the rate of decrease positively correlated to the impact energy. The residual voltage Ures changes by less than 5% . Using leakage current as a standard can more intuitively reflect the aging condition of MOVs. By analyzing the failure conditions of MOVs after multiple impacts at different energy levels，a relationship between impact energy and the statistical failure count N50% is established. A finite element simulation is used to develop a MOV failure model， investigating the distribution of current，temperature，and stress within microcrystals，as well as the failure threshold，with experimental validation of the model's accuracy. The results indicate that the prediction error for the failure threshold is 8% . and the prediction error for temperature under various energy impacts is less than 5%

Keywords： metal oxide varistors;degradation; failure; direct current interruption

随着可再生能源的快速发展和电力需求的不断增加，直流输电技术因其低损耗、高效率和灵活性而日益受到重视[1-3]。（剩余17790字）