A model for availability growth with application to new generation offshore wind farms

Zitrou, Athena; Bedford, Tim; Walls, Lesley

doi:10.1016/j.ress.2015.12.004

Cited by 17 publications

(12 citation statements)

References 30 publications

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“…This methodology allows for changing failure intensity function throughout the simulated lifetime. As a greater understanding of offshore WT failure behavior is developed through operator experience, it will become possible to model design life changes or impacts of climate and maintenance such as in Zitrou et al 22 However, for this study, a beta value equal to 1 has been used corresponding to constant failure intensity. At each time-step, a uniformly distributed random number, N , in the interval 0 to 1 is generated and used to determine if a failure has occurred using the criteria in equation (5) and passed to the operational simulation block.…”

Section: Model Descriptionmentioning

confidence: 99%

On modeling insights for emerging engineering problems: A case study on the impact of climate uncertainty on the operational performance of offshore wind farms

Dinwoodie¹,

McMillan²,

Lazakis³

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part O:

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This paper considers the technical and practical challenges involved in modelling emerging engineering problems. The inherent uncertainty and potential for change in operating environment and procedures adds significant complexity to the model development process. This is demonstrated by considering the development of a model to quantify the uncertainty associated with the influence of the wind and wave climate on the energy output of offshore wind farms which may result in sub-optimal operating decisions and site selection due to the competing influence of wind speed on power production and wave conditions on availability. The financial profitability of current and future projects may be threatened if climate uncertainty is not included in the planning and operational decision making process. A comprehensive climate and wind farm operational model was developed using a time series Monte Carlo simulation to model the performance of offshore wind farms, identifying non-linear relationships between climate, availability, energy output and capacity factor. This model was evaluated by engineers planning upcoming offshore wind farms to determine its usefulness for supporting operational decision making. From this, new consideration was given to the challenges in developing and applying complex simulations for emerging engineering problems.

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Section: Model Descriptionmentioning

confidence: 99%

On modeling insights for emerging engineering problems: A case study on the impact of climate uncertainty on the operational performance of offshore wind farms

Dinwoodie¹,

McMillan²,

Lazakis³

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part O:

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“…This is based on the number of restoration actions. Also different methods and availability models which can be used in the industry are discussed in [11], [12], [13] and [14]. In [15] UML activity diagram was converted into CPN through an automatic method.…”

Section: Previous Studiesmentioning

confidence: 99%

Availability Assessment of Software Systems Architecture Using Formal Models

Sadeghian¹,

Motameni²

2018

IJCATR

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There has been a significant effort to analyze, design and implement the information systems to process the information and data, and solve various problems. On the one hand, complexity of the contemporary systems, and eye-catching increase in the variety and volume of information has led to great number of the components and elements, and more complex structure and organization of the information systems. On the other hand, it is necessary to develop the systems which meet all of the stakeholders' functional and non-functional requirements. Considering the fact that evaluation and assessment of the aforementioned requirements -prior to the design and implementation phases -will consume less time and reduce costs, the best time to measure the evaluable behavior of the system is when its software architecture is provided. One of the ways to evaluate the architecture of software is creation of an executable model of architecture. The present research used availability assessment and took repair, maintenance and accident time parameters into consideration. Failures of software and hardware components have been considered in the architecture of software systems. To describe the architecture easily, the authors used Unified Modeling Language (UML). However, due to the informality of UML, they utilized Colored Petri Nets (CPN) for assessment too. Eventually, the researchers evaluated a CPN-based executable model of architecture through CPN-Tools.

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“…The model can be improved in the future research, some possible topics include the following: (1) the availability concept used in this study is so-called time-based availability, while considering ''energy-based availability'' may be more practical in power industries. 35,42 (2) When the availability-based warranty is used for particular devices, such as nuclear plant, point availability may be more reasonable. 43 (3) Due to the factors including production schedule and operating environment, the usage rate of equipment is usually uncertain.…”

Section: Conclusion and Future Research Workmentioning

confidence: 99%

“…A variety of factors can affect the availability, for example, product design, manufacturing technique, operational environment, supply of spare parts, and maintenance methods. 35 Generally, the operational availability ( A ) can be defined by mean uptime (MUT) and mean downtime (MDT) of each cycle 37…”

Section: Model Formulationmentioning

confidence: 99%

See 1 more Smart Citation

An availability-based warranty policy considering preventive maintenance and learning effects

Cheng

2017

Proceedings of the Institution of Mechanical Engineers, Part O:

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By considering learning effects during the process of maintenance, this article investigates an availability-based warranty policy from the manufacturer's perspective. Imperfect preventive maintenance activities are implemented to reduce the number of equipment failures so as to meet the product's availability requirement and minimize warranty servicing cost during the warranty period. Hybrid hazard rate model is used to describe imperfect preventive maintenance actions; maintenance plan and warranty servicing cost are optimized by considering learning effects. Preventive maintenance schedule within a warranty period is optimized cycle by cycle, and the warranty cost rate is minimized under the requirement of availability within each cycle. Numerical example of a wind turbine gearbox is provided to verify the effectiveness of the proposed availability-based warranty policy. Sensitivity analysis shows that by considering learning effects on maintenance, the gearbox can maintain a higher availability level with a lower warranty cost than the case without consideration of learning effects.

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A model for availability growth with application to new generation offshore wind farms

Cited by 17 publications

References 30 publications

On modeling insights for emerging engineering problems: A case study on the impact of climate uncertainty on the operational performance of offshore wind farms

On modeling insights for emerging engineering problems: A case study on the impact of climate uncertainty on the operational performance of offshore wind farms

Availability Assessment of Software Systems Architecture Using Formal Models

An availability-based warranty policy considering preventive maintenance and learning effects

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