Parameters Influencing Reliability and Availability of the System

2014 ◽  
pp. 15-16
Author(s):  
Ivica Kuzmanić ◽  
Igor Vujović
Keyword(s):  
Reliability And Availability

scholarly journals Simulation Model to Analyze the Consequences of DC Faults in MMC-Based HVDC Stations

Electricity ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 124-142
Author(s):  
Davin Guedon ◽  
Philippe Ladoux ◽  
Sébastien Sanchez ◽  
Sébastien Cornet
Keyword(s):  
Power Transmission ◽  
Renewable Energy Sources ◽  
Energy Sources ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Circuit Breakers ◽  
High Voltage Direct Current ◽  
Proposed Model ◽  
Proper Design ◽  
Reliability And Availability

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.

Operation and approximation based on the history of failure modes recorded by SCADA system of Amougdoul Moroccan wind farm using FMECA maintenance model

2021 ◽  
pp. 0309524X2199245
Author(s):  
Kawtar Lamhour ◽  
Abdeslam Tizliouine
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Failure Modes ◽  
Wind Farms ◽  
Scada System ◽  
History Of ◽  
Criticality Analysis ◽  
Maintenance Model ◽  
Reliability And Availability ◽  
Critical Subsystems

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.

Tree-Structured Parallel Regeneration Based on Regenerating Codes for Multiple Data Losses in Distributed Storage Systems

2014 ◽  
Vol 918 ◽  
pp. 295-300
Author(s):  
Peng Fei You ◽  
Yu Xing Peng ◽  
Zhen Huang ◽  
Chang Jian Wang
Keyword(s):  
Storage Systems ◽  
Distributed Storage ◽  
Data Loss ◽  
Data Reliability ◽  
Data Redundancy ◽  
Regeneration Time ◽  
Multiple Data ◽  
Distributed Storage Systems ◽  
Regenerating Codes ◽  
Reliability And Availability

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.

An Optimal Service Selection with Constraints Based on QoS Algorithm

2012 ◽  
Vol 487 ◽  
pp. 357-364
Author(s):  
Xin Jun Li
Keyword(s):  
Computing Time ◽  
Service Selection ◽  
Optimal Service ◽  
Availability Constraints ◽  
The One ◽  
Qos Performance ◽  
The Impact ◽  
Structural Aspects ◽  
Reliability And Availability

In the paper, we propose an allocation scheme that minimizes the response time and cost of the solution subject to reliability and availability constraints in terms of expected value. The algorithm proposed in this paper aims to discover services with high QoS performance, and reduce the execute time at the same time. First, we identify the impact of various structural aspects of the composition in terms of the performance and outcomes of the composition. Then, an algorithm is proposed which can reduce the computing time and makes sure better quality of the services selection at the same time by examining a very tiny fraction of the solution space.Finally, we proves the advantage of the new algorithm by comparing the time obtained by our proposed algorithm with the one achieved by other algorithm.

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