Improving BOP reliability and availability through RAM analysis and expanded FMEA scope

Author(s):  
K Nouri
2021 ◽  
Author(s):  
Graham Nicholson ◽  
Graham Brown ◽  
Ben Seymour

Abstract Remotely operated and unmanned facilities offer significant safety, environmental and economic benefits over conventional facilities. This paper describes the key elements for successful design and an approach for evaluating the reliability, availability and TOTEX of unmanned facilities. The approach was developed during the concept and FEED phases of a wellhead platform project and forms the basis of the unmanned strategy going forwards but can also be used for facilities with partial processing topsides. During the design of a recent platform it became clear that normal FMEA/RAM analysis was not suitable for assessing the reliability and availability of unmanned facilities with low visit frequency. Drawing on previous experience, a new approach was developed to address the specific challenges of low maintenance intervals and provide a methodical approach to proving reliability. The new approach improved confidence in the predicted availability by identifying key components and appropriate reliability data. The process adds some extra steps to typical reliability and availability assessment, which are designed to address the specific demands of unmanned operations. The result of this work has given a clearer understanding of how reliability can be assessed and managed for low-manned or unmanned applications. The methodology helps to identify unmanned /low manned opportunities and provides guidance on design and reliability assessment It is observed that system reliability is usually driven by a few key components and that whilst many components have good overall reliability data this may not be applicable for the proposed specific operating environment and maintenance regime of an unmanned platform. It is therefore essential to evaluate components individually for their specific applications. It is concluded that to achieve the unmanned goal it is vital to fully understand the system and component reliability early in the project. The proposed methodology can be applied at any stage to validate the design, confirm assumptions, or identify gaps.


Electricity ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 124-142
Author(s):  
Davin Guedon ◽  
Philippe Ladoux ◽  
Sébastien Sanchez ◽  
Sébastien Cornet

The global development of high-voltage direct-current (HVDC) systems in fields such as renewable energy sources, interconnection of asynchronous grids or power transmission over great distances, is unquestionably important. Though widely used, the modular multilevel converter with half-bridge cells is sensitive to DC pole-to-pole faults and the time-response of the protections is critical. Reliability and availability are paramount: circuit-breakers must minimize the effects of any fault on the converter, while ensuring rapid restart. This paper focuses on the modelling aspects to analyse the behaviour of HVDC stations during DC pole-to-pole faults, using either AC or DC circuit-breakers, with different parameters. The proposed model can represent the main issues met by the converter cells during DC faults, such as semiconductor overcurrents and overvoltages, allowing a proper design of the cells.


2021 ◽  
pp. 0309524X2199245
Author(s):  
Kawtar Lamhour ◽  
Abdeslam Tizliouine

The wind industry is trying to find tools to accurately predict and know the reliability and availability of newly installed wind turbines. Failure modes, effects and criticality analysis (FMECA) is a technique used to determine critical subsystems, causes and consequences of wind turbines. FMECA has been widely used by manufacturers of wind turbine assemblies to analyze, evaluate and prioritize potential/known failure modes. However, its actual implementation in wind farms has some limitations. This paper aims to determine the most critical subsystems, causes and consequences of the wind turbines of the Moroccan wind farm of Amougdoul during the years 2010–2019 by applying the maintenance model (FMECA), which is an analysis of failure modes, effects and criticality based on a history of failure modes occurred by the SCADA system and proposing solutions and recommendations.


2014 ◽  
Vol 918 ◽  
pp. 295-300
Author(s):  
Peng Fei You ◽  
Yu Xing Peng ◽  
Zhen Huang ◽  
Chang Jian Wang

In distributed storage systems, erasure codes represent an attractive data redundancy solution which can provide the same reliability as replication requiring much less storage space. Multiple data losses happens usually and the lost data should be regenerated to maintain data redundancy in distributed storage systems. Regeneration for multiple data losses is expected to be finished as soon as possible, because the regeneration time can influence the data reliability and availability of distributed storage systems. However, multiple data losses is usually regenerated by regenerating single data loss one by one, which brings high entire regeneration time and severely reduces the data reliability and availability of distributed storage systems. In this paper, we propose a tree-structured parallel regeneration scheme based on regenerating codes (TPRORC) for multiple data losses in distributed storage systems. In our scheme, multiple regeneration trees based on regenerating code are constructed. Firstly, these trees are created independently, each of which dose not share any edges from the others and is responsible for one data loss; secondly, every regeneration tree based on regenerating codes owns the least network traffic and bandwidth optimized-paths for regenerating its data loss. Thus it can perform parallel regeneration for multiple data losses by using multiple optimized topology trees, in which network bandwidth is utilized efficiently and entire regeneration is overlapped. Our simulation results show that the tree-structured parallel regeneration scheme reduces the regeneration time significantly, compared to other regular regeneration schemes.


Sign in / Sign up

Export Citation Format

Share Document