基于竞争失效的低压开关电器可靠性建模方法研究

Research on the Reliability Modeling Method for Low-voltage Switches Based on Competing Failure

低压开关电器在其运行过程中同时存在退化失效模式和偶然失效模式,两者实质上是竞争失效的关系。根据低压开关电器失效模式和失效规律的特点,提出基于竞争失效的低压开关电器可靠性建模方法,解决低压开关电器难以实现全面可靠性评估的问题。将累积电弧侵蚀量作为退化特征量,采用带漂移的一元线性维纳(Wiener)过程描述电性能退化过程,采用指数分布描述偶然失效。首先仿真产生偶然失效寿命,并基于Wiener过程仿真产品累积电弧侵蚀量,得到产品的竞争失效寿命,然后建立基于竞争失效的低压开关电器可靠性模型,采用极大似然估计方法进行模型参数估计,最后在不同失效情况下进行基于退化失效、基于偶然失效和基于竞争失效建模方法的可靠性评估,实现不同失效情况下的低压开关电器可靠性评估。通过模拟试验从理论上验证了基于竞争失效的低压开关电器可靠性建模方法能够全面、客观和准确地评估产品可靠性,并且在不同的失效情况下可以根据实际需求选择不同的可靠性建模方法,对低压开关电器可靠性分析具有指导意义。

The failure of a low-voltage switch is determined by the competition of two failure modes, the degradation failure mode and the random failure mode. According to the failure characteristics and the failure modes of low-voltage switches,this paper proposed a modeling method based on the competing failure process to solve the difficulty in e va lua ti ng th e re lia bility of low-v olta ge swi tc he s comprehensively. For the degradation failure mode, the accumulation of contact loss caused by arc erosion was used as the degradation parameter, and the one-dimension Wiener process with linear drift was used to describe the degradation process. And for the random failure mode, the exponential distribution was used to describe the failure process. First, the random failure life were generated by simulation. Second, the accumulation loss due to arc erosion were obtained based on the Wiener process for each life and the competing failure life was calculated. Then, the reliability model based on competing failure was established and the maximum likelihood estimation was used to estimate the model parameters. Finally, three modeling methods based on the degradation failure mode, the random failure mode and the competition of them were tested in simulation to evaluate the reliability of the same failure situation with the two failure modes, and the effectiveness of the competing failure modeling method for evaluating the reliability of low-voltage switches was validated theoretically. Furthermore, the analysis in this paper also shows that, according to the practical demands, one can choose different model to evaluate the reliability of products under different failure situations, which can provide valuable reference for the reliability analysis of low-voltage switches.