Operation-based Reliability Assessment of Shore-to-Ship Charging Systems

In this paper, reliability of Shore-to-Ship Charging (S2SC) systems is evaluated based on the operational profile such as charging power- and planning of on-board batteries. Other operational parameters are also considered in the reliability analysis such as night charging planning and the onshore battery scheduling. For this objective, a reliability model is established where the failure rates of the components are estimated based on FIDES method. Then, a dynamic failure threshold is introduced to describe the reliability of the system under operation in three states such as failed, normal operation, and derated operation. In such procedure, the failure threshold is specifically obtained for a set of operational parameters and system sizing. In the end, the reliability evaluation is carried out for a 4MW dc S2SC system. The results show that batteries and the IGBTs in the power electronics converters are the most reliability-critical elements. Further, it concluded that recharging the onshore batteries with higher power within can improve the reliability. Moreover, the range of onshore battery discharging power with lowest loss of charging expected is found to be between 1.5MW and 2.5MW for the studied configuration.