Belief Reliability Modeling and Analysis for Motion Accuracy of the UHV DC Disconnector Mechanism

Insufficient motion accuracy in the operating mechanism of an Ultra-High Voltage Direct Current (UHV DC) disconnector can readily lead to deviations from the intended opening/closing positions, potentially triggering operational failures. The uncertainties and performance degradation prevalent during both manufacturing and service significantly impact its reliability. To address this, this paper proposes a belief reliability modeling method specifically for the motion accuracy of such mechanisms, based on Belief Reliability theory. Firstly, a theoretical model for calculating the motion accuracy margin is established, comprehensively considering wear, dimensional errors, fitting clearances, thermal deformation, and elastic deformation. Secondly, the sources and characteristics of uncertainties are systematically analyzed, and various uncertainty factors are quantified using probability distributions. Finally, a reliability model for the motion accuracy of the DC disconnector operating mechanism is constructed. Taking a specific mechanism model as the research object, reliability and sensitivity analyses are conducted. The results demonstrate that the proposed method can provide a theoretical basis and engineering guidance for the reliability-forward design and reliability improvement of DC isolation switches.