Improved reliability assessment of valve hall: Considering failure correlation

Abstract. Valve hall is the core system of converter stations and is critical for the operation of power systems. It is necessary to conduct seismic reliability assessments based on real response data. Traditional system reliability assessments are based on the response states of individual structures and the functional dependencies between them, typically assuming that the response states of different structures are completely independent. However, complex interactions exist between system components, meaning that such assumptions may lead to inaccurate assessment results. Copula method provides an effective tool for modeling the dependency structure between variables. By developing a detailed finite element model of the valve hall system, the actual response states of various equipment under seismic conditions are simulated. D-Vine Copula model is used to construct the dependency structure among the equipment response states, enabling a seismic reliability assessment of the valve hall system that accounts for equipment correlations. Comparisons reveal that reliability assessment methods based on the assumption of complete independence among components tend to underestimate the seismic performance of the valve hall system. This further confirms the necessity of considering the correlations between the response states of components in reliability assessments.