Towards scalable system-level reliability analysis

PurposeA reliability analysis of a solid oxide fuel cell (SOFC) system is presented for applications with strict constant power supply requirements, such as data centers. The purpose is to demonstrate the effect when moving from a module-level to a system-level in terms of reliability, also considering effects during start-up and degradation.Design/methodology/approachIn-house experimental data on a system-level are used to capture the behavior during start-up and normal operation, including drifts of the operation point due to degradation. The system is assumed to allow replacement of stacks during operation, but a minimum number of stacks in operation is needed to avoid complete shutdown. Experimental data are used in conjunction with a physics-based performance model to construct the failure probability function. A dynamic program then solves the optimization problem in terms of time and replacement requirements to minimize the total negative deviation from a given target reliability.FindingsResults show that multi-stack SOFC systems face challenges which are only revealed on a system- and not on a module-level. The main finding is that the reliability of multi-stack SOFC systems is not sufficient to serve as sole power source for critical applications such as data center.Practical implicationsThe principal methodology may be applicable to other modular systems which include multiple critical components (of the same kind). These systems comprise other electrochemical systems such as further fuel cell types.Originality/valueThe novelty of this work is the combination of mathematical modeling to solve a real-world problem, rather than assuming idealized input which lead to more benign system conditions. Furthermore, the necessity to use a mathematical model, which captures sufficient physics of the SOFC system as well as stochasticity elements of its environment, is of critical importance. Some simplifications are, however, necessary because the use of a detailed model directly in the dynamic program would have led to a combinatorial explosion of the numerical solution space.

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Component and system-level reliability analysis of riprap layer around bridge pier in clear water condition

ISH Journal of Hydraulic Engineering ◽

10.1080/09715010.2019.1711206 ◽

2020 ◽

pp. 1-10

Author(s):

Mojtaba Karimaei Tabarestani ◽

Amin Salamatian ◽

Mehdi Panahi Azad

Keyword(s):

Reliability Analysis ◽

Bridge Pier ◽

System Level ◽

Clear Water ◽

Water Condition

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Reliability Analysis of Shiplift Gear Based on System-Level Load-Strength Interference Model

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.118-120.354 ◽

2010 ◽

Vol 118-120 ◽

pp. 354-358

Author(s):

Ying Wu ◽

Li Yang Xie ◽

De Cheng Wang ◽

Ji Zhang Gao

Keyword(s):

Reliability Analysis ◽

Order Statistic ◽

System Reliability ◽

Bending Strength ◽

High Reliability ◽

Interference Model ◽

System Level ◽

Maximum Order ◽

Minimum Order ◽

Analysis System

A reliability analysis method for the shiplift gear according to the system-level load-strength interference model is presented. The gear is regarded as a series system with dependent failure and multiple failure models. Its reliability is obtained by calculating the probability that the minimum order statistic of the strengths exceeds the maximum order statistic of repeated random loads. The load probability distribution of gear is then obtained using Monte Carlo on the basis of load information. The contact strength and bending strength are calculated. On the basis of system-level load-strength interference analysis, system reliability of a gear is straightforward built up. Finally, system reliability of a gear is worked out, which shows a high reliability.

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Energy Storage for 1500 V Photovoltaic Systems: A Comparative Reliability Analysis of DC- and AC-Coupling

Energies ◽

10.3390/en13133355 ◽

2020 ◽

Vol 13 (13) ◽

pp. 3355 ◽

Cited By ~ 3

Author(s):

Jinkui He ◽

Yongheng Yang ◽

Dmitri Vinnikov

Keyword(s):

Energy Storage ◽

Reliability Analysis ◽

System Level ◽

Solar Pv ◽

Pv System ◽

Battery System ◽

Pv Systems ◽

Pv Inverter ◽

Cost Of Energy ◽

Battery Energy

There is an increasing demand in integrating energy storage with photovoltaic (PV) systems to provide more smoothed power and enhance the grid-friendliness of solar PV systems. To integrate battery energy storage systems (BESS) to an utility-scale 1500 V PV system, one of the key design considerations is the basic architecture selection between DC- and AC-coupling. Hence, it is necessary to assess the reliability of the power conversion units, which are not only the key system components, but also represent the most reliability-critical parts, in order to ensure an efficient and reliable 1500 V PV-battery system. Thus, this paper investigates the BESS solutions of DC- and AC-coupled configurations for 1500 V PV systems with a comparative reliability analysis. The reliability analysis is carried out through a case study on a 160 kW/1500 V PV-system integrated DC- or AC-coupled BESS for PV power smoothing and ramp-rate regulation. In the analysis, all of the DC-DC and DC-AC power interfacing converters are taken into consideration along with component-, converter-, and system-level reliability evaluation. The results reveal that the reliability of the 1500 V PV inverter can be enhanced with the DC-coupled BESS, while seen from the system-level reliability (i.e., a PV-battery system), both of the DC- and AC-coupled BESSs will affect the overall system reliability, especially for the DC-coupled case. The findings can be added into the design phase of 1500 V PV systems in a way to further lower the cost of energy.

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