An analytical approach to evaluate the reliability of offshore wind power plants considering environmental impact

The accurate quantitative reliability evaluation of offshorewind power plants (OWPPs) is an important part in planning and helps us to obtain economic optimization. However, loop structures in collector systems and large quantities of components with correlated failures caused by shared ambient influences are significant challenges in the reliability evaluation. This paper proposes an analytical approach to evaluate the reliability of OWPPs considering environmental impact on failures and solve the challenges by protection zone models, equivalent power unit models, and common cause failure (CCF) analysis. Based on the investigation of the characteristics of OWPP and related failures mechanisms, the components are divided into three CCF subsets. With the aid of the protection zonemodel and equivalent power unitmodel merged with CCF, the faulty collector system state evaluation is applied to reduce the computational burden. The case studies present the necessity and improved performance of merging CCF analysis into modeling via the comparison with other two simplified methods. A sensitivity analysis is also carried out to account for inaccuracy of failure data. The results show that the assumption of independent failures in the conventional method might lead to over-optimistic or over-pessimistic evaluation depending on the CCF style.