A Multilayer Framework for Reliability Assessment of Shore-to-Ship Fast Charging System Design

Abstract

In this paper, a multi-layer framework is proposed to assess the reliability of Shore-to-Ship Charging (S2SC) systems, considering the potential for failures of the main elements, such as power converters and batteries. The proposed reliability model enables evaluating a S2SC system with redundancy, multi-state system availability, and multi-variable design scenarios, based on a recursive algorithm. Instead of conventional Markov-chain multi-state models, a reduced order state-space model is established from a set of specific sub-systems with a predefined configuration complying with the design requirements. A modular approach is taken, and the probabilistic characteristics of the subsystems are established by developing a Universal Generating Function considering the available charging power and energy balance constraints. Then, the sub-systems are integrated into the system configuration to assess a set of proposed applicationspecific system-level reliability indices. Thus, the modular approach enables expansion to the power system dimensions without extra complexity. Finally, a case study based on an operating 4-MW dc S2SC system is performed by the proposed framework, and design suggestions are given based on a figure of merit defined for evaluation of reliability and energy efficiency. These design suggestions include resizing the charging system by installing onshore batteries, modularization, and introduction of redundancy in the sub-systems.

Operation-Based Reliability Assessment of Shore-to-Ship Charging Systems Including On-Shore Batteries

“…Note that the dormant phases are also considered in this method. In order to obtain the temperature profile required to calculate these acceleration factors, the electrothermal models of the parts, as described in [13], are used. The detailed failure rate models can be found in [19].…”

“…As discussed in [7], such reliability indices can be redefined To better capture the specific behaviors of an S2SC system. Suitable indicators can, for instance, be associated with the probability of accomplishing the charging missions such that the vessel can operate with its OBB recharged according to the schedule [13].…”

“…Regarding reliability studies for S2SC systems, only a few research papers can be found in the literature [7], [13], [25].…”

“…In [7], the reliability of dc and ac S2SC systems are assessed by the Markov chain approach, and several application-specific reliability indices are introduced. Moreover, based on the same reliability indices, a design-based reliability framework for S2SC systems is proposed in [13]. That work provided a platform for reliable design and sizing of the S2SC systems supported by OSB.…”

A multi‐layer framework for energy efficiency assessment of shore‐to‐ship fast charging systems including onshore batteries

“…To quantify the dependency of the results to the applied parameters, a sensitivity analysis of the calculated energy efficiency in terms of selected parameters is carried out. The proposed framework is also applicable as part of a comprehensive objective function for optimization of S2SC systems by integrating other influencing factors in the design phase, for example, reliability [27], cost, and quay space.…”