Importance measure of multi-state element variation based on F-VMEA

Classical multi-state system (MSS) reliability theory mainly emphasizes the reliability modeling of the system, while the analysis of the elements states and their variations are very little in use. Additionally, few literatures estimate importance of detrimental variation instead of only importance of multi-state element in MSS. Therefore, this paper proposes an analysis method which not only concentrates on analyzing multi-state element but also its variations. In this article, firstly, a comprehensive method which is called failure-variation mode and effect analysis (F-VMEA) is proposed aiming at finding and assessing unwanted variations, degradation and failure of elements. Secondly, the Photovoltaic (PV) system is studied according to the proposed F-VMEA. Finally, according to the results of F-VMEA, a relative good reliability model of PV system is established by universal generating function (UGF) technique and the importance measure of any element can be estimated.