scholarly journals Reliability Assessment of a Fault-Tolerant PV Multistring Inverter

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6525
Author(s):  
Hugues Renaudineau ◽  
Pol Paradell-Solà ◽  
Lluís Trilla ◽  
Alber Filba-Martinez ◽  
David Cardoner ◽  
...  
Keyword(s):  
Fault Tolerant ◽  
Cost Effective ◽  
Power Converter ◽  
Reliability Estimation ◽  
Time To Failure ◽  
Pv Systems ◽  
Conventional Structure ◽  
Power Electronics Converter ◽  
Mean Time ◽  
Design Power

In photovoltaic (PV) systems, the reliability of the system components, especially the power converters, is a major concern in obtaining cost effective solutions. In order to guarantee service continuity in the case of failure of elements of the PV converter, in particular, semiconductor switching devices, a solution is to design power converter with fault-tolerance capability. This can be realized by aggregating hardware redundancy on an existing converter, providing the possibility of replacement of faulty elements. This paper evaluates the reliability of a fault-tolerant power electronics converter for PV multistring application. The considered fault-tolerant design includes a single redundant switching leg, which is used in order to reconfigure the structure in case of a switch failure either on DC-AC or DC-DC stages. This paper details the reliability estimation of the considered PV multistring fault-tolerant converter. Furthermore, a comparison with a conventional structure without fault-tolerant capability is provided. The results show that the introduction of a single redundant leg allows for improving the converter mean time to failure by a factor of almost two and it reduces, by half, the power loss due to system-failure shutdowns in PV applications, while only increasing the converter cost by 2–3%.

Performance Assessment of Indian Meteorological Ocean Buoys With INSAT Telemetry

2016 ◽  
Vol 50 (6) ◽  
pp. 33-39 ◽  
Author(s):  
Ranganathan Sundar ◽  
Ramasamy Venkatesan ◽  
Manickavasagam Arul Muthiah ◽  
Narayanaswamy Vedachalam ◽  
Malayath Aravindakshan Atmanand
Keyword(s):  
Meteorological Data ◽  
Cost Effective ◽  
Time To Failure ◽  
Critical Systems ◽  
Safety Integrity Level ◽  
Integrity Management ◽  
The Indian Ocean ◽  
Oceanographic Data ◽  
Ocean Monitoring ◽  
Mean Time

AbstractThis paper assesses the reliability of data reception of the offshore moored Indian meteorological buoys equipped with INSAT telemetry and used for monitoring the Indian seas. Based on 11,952 data transmissions spanning 4.2 buoy-years, the data reception performance of the INSAT-based telemetry system is found to be 98.74%, with a corresponding data “mean time to failure” (MTTF) of 51 h. It is also identified that the moored buoy telemetry hardware conforms to an IEC 61508 Safety Integrity Level 4. The identified reliability results serve as a guideline for offshore system designers using INSAT telemetry. Meteorological data buoys with INSAT telemetry shall provide an opportunity for collecting extensive and cost-effective oceanographic data, which are used for improving the effectiveness of the Indian Ocean monitoring programs and for cost-effective integrity management of critical systems used for tsunami early warnings.

Transient analysis of computing system with reboot and recovery delay

2020 ◽  
Vol 37 (6/7) ◽  
pp. 983-1005
Author(s):  
Chandra Shekhar ◽  
Amit Gupta ◽  
Madhu Jain ◽  
Neeraj Kumar
Keyword(s):  
Sensitivity Analysis ◽  
Fault Tolerant ◽  
Transient State ◽  
Recovery Process ◽  
Computing System ◽  
Time To Failure ◽  
Mean Time To Failure ◽  
Content Type ◽  
Imperfect Coverage ◽  
Mean Time

PurposeThe purpose of this paper is to present a sensitivity analysis of fault-tolerant redundant repairable computing systems with imperfect coverage, reboot and recovery process.Design/methodology/approachIn this investigation, the authors consider the computing system having a finite number of identical working units functioning simultaneously with the provision of standby units. Working and standby units are prone to random failure in nature and are administered by unreliable software, which is also likely to unpredictable failure. The redundant repairable computing system is modeled as a Markovian machine interference problem with exponentially distributed failure rates and service rates. To excerpt the failed unit from the computing system, the system either opts randomized reboot process or leads to recovery delay.FindingsTransient-state probabilities have been determined with which the authors develop various reliability measures, namely reliability/availability, mean time to failure, failure frequency, and so on, and queueing characteristics, namely expected number of failed units, the throughput of the system and so on, for the predictive purpose. To spectacle the practicability of the developed model, a numerical simulation, sensitivity analysis and so on for different parameters have also been done, and the results are summarized in the tables and graphs. The transient results are helpful to analyze the developing model of the system before having the stability of the system. The derived measures give direct insights into parametric decision-making.Social implicationsThe conclusion has been drawn, and future scope is remarked. The present research study would help system analyst and system designer to make a better choice/decision in order to have the economical design and strategy based on the desired mean time to failure, reliability/availability of the systems and other queueing characteristics.Originality/valueDifferent from previous investigations, this studied model provides a more accurate assessment of the computing system compared to uncertain environments based on sensitivity analysis.

Reliability Prediction of Computing Network with Software and Hardware Failures

2019 ◽  
Vol 27 (02) ◽  
pp. 2040006
Author(s):  
Chandra Shekhar ◽  
Neeraj Kumar ◽  
Madhu Jain ◽  
Amit Gupta
Keyword(s):  
Fault Tolerant ◽  
Transient State ◽  
Reliability Prediction ◽  
Time To Failure ◽  
Failure Times ◽  
Machine Interference ◽  
Random Failure ◽  
Software And Hardware ◽  
Hardware Failures ◽  
Mean Time

In this paper, we investigate the reliability and queueing performance indices for the fault-tolerant computing network having a finite number of unreliable operating components with the provision of warm standby components. Operating and standby components are governed by dedicated software which is also prone to random failure. On failure of operating components, available standby component(s) may switch from the standby state to operating state with negligible switchover time. The switchover process may also fail due to some automation hindrance. The computing network is also subjected to common cause failure in lieu of external cause. The studied redundant fault-tolerant computing network is framed as a Markovian machine interference model with exponentially distributed inter-failure times and service times. For the reliability prediction of the computing network, various performance measures, namely, mean-time-to-failure (MTTF), reliability/availability, failure frequency, etc., have been formulated in terms of transient-state probabilities which we have obtained using the spectral method. To show the practicability of the developed model, numerical simulation has been done. Sensitivity analysis of reliability and other indices of the computing network with respect to different network parameters has been presented, and results are summarized in the tables and graphs. Finally, future scope and concluding remarks have been included.

Self-Repair Technology for Global Interconnects on SoCs

2011 ◽  
pp. 195-215
Author(s):  
Daniel Scheit ◽  
Heinrich Theodor Vierhaus
Keyword(s):  
Fault Tolerant ◽  
High Current Density ◽  
Time To Failure ◽  
Transient Faults ◽  
The Mean ◽  
Self Repair ◽  
Global Interconnects ◽  
Low K ◽  
Mean Time ◽  
Static Faults

The reliability of interconnects on ICs has become a major problem in recent years, due to the rise of complexity, low-k-insulating material with reduced stability, and wear-out-effects due to high current density. The total reliability of a system on a chip is more and more dependent on the reliability of interconnects. The growing volume of communication due to the increasing number of integrated functional units is the main reason. Articles have been published, which predict that static faults due to wear-out effects will occur more often. This will harm the reliability and decrease the mean-time-to-failure. Most of the published techniques are aimed at the correction of transient faults. Built-in self-repair has not been discussed as much as the other techniques. In this chapter, the authors will provide an overview over the state of the art for fault-tolerant interconnects. They will discuss the use of built-in self repair in combination with other approved solutions. The combination is a promising way to deal with all kinds of faults.

scholarly journals Network Survivability Performance Evaluation in Underwater Surveillance System Using Markov Model

2014 ◽  
Vol 3 (3) ◽  
pp. 147-157
Author(s):  
Seyyed Yahya Nabavi ◽  
Reza Mohammadi ◽  
Manijeh Keshtgari
Keyword(s):  
Performance Evaluation ◽  
Surveillance System ◽  
Sensor Node ◽  
Markov Models ◽  
Fault Tolerant ◽  
Time To Failure ◽  
Underwater Environment ◽  
Proposed Model ◽  
Military Applications ◽  
Mean Time

Underwater Wireless Sensor Network (UWSN) is a useful technology that can be used in Underwater Surveillance System (USS). USSs are mostly used in military purposes for detecting underwater military activities. One of the most important issues in USS is mission reliability or survivability. Due to harsh underwater environment and mission critical nature of military applications, it is important to measure survivability of USS. Underwater sensor node failures can be detrimental for USS. To improve survivability in USS, we propose a fault-tolerant underwater sensor node model. To the best of our knowledge, this is the first fault-tolerant underwater sensor node model in USS that evaluates survivability of an USS.  We develop Markov models for characterizing USS survivability and MTTF (Mean Time to Failure) to facilitate USS. Performance evaluation results show the effectiveness of proposed model.

scholarly journals Surveillance System in Smart Cities: A Dependability Evaluation Based on Stochastic Models

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 876
Author(s):  
Igor Gonçalves ◽  
Laécio Rodrigues ◽  
Francisco Airton Silva ◽  
Tuan Anh Nguyen ◽  
Dugki Min ◽  
...  
Keyword(s):  
Surveillance System ◽  
Smart Cities ◽  
Heterogeneous Data ◽  
Time To Failure ◽  
Video Streams ◽  
Dependability Evaluation ◽  
The Mean ◽  
Mean Time ◽  
The Internet Of Things

Surveillance monitoring systems are highly necessary, aiming to prevent many social problems in smart cities. The internet of things (IoT) nowadays offers a variety of technologies to capture and process massive and heterogeneous data. Due to the fact that (i) advanced analyses of video streams are performed on powerful recording devices; while (ii) surveillance monitoring services require high availability levels in the way that the service must remain connected, for example, to a connection network that offers higher speed than conventional connections; and that (iii) the trust-worthy dependability of a surveillance system depends on various factors, it is not easy to identify which components/devices in a system architecture have the most impact on the dependability for a specific surveillance system in smart cities. In this paper, we developed stochastic Petri net models for a surveillance monitoring system with regard to varying several parameters to obtain the highest dependability. Two main metrics of interest in the dependability of a surveillance system including reliability and availability were analyzed in a comprehensive manner. The analysis results show that the variation in the number of long-term evolution (LTE)-based stations contributes to a number of nines (#9s) increase in availability. The obtained results show that the variation of the mean time to failure (MTTF) of surveillance cameras exposes a high impact on the reliability of the system. The findings of this work have the potential of assisting system architects in planning more optimized systems in this field based on the proposed models.

On classes of life distributions based on the mean time to failure function

2021 ◽  
Vol 58 (2) ◽  
pp. 289-313
Author(s):  
Ruhul Ali Khan ◽  
Dhrubasish Bhattacharyya ◽  
Murari Mitra
Keyword(s):  
Damage Model ◽  
Replacement Policy ◽  
Time To Failure ◽  
Mean Time To Failure ◽  
Moment Convergence ◽  
Life Distributions ◽  
Cumulative Damage Model ◽  
The Mean ◽  
Age Replacement ◽  
Mean Time

AbstractThe performance and effectiveness of an age replacement policy can be assessed by its mean time to failure (MTTF) function. We develop shock model theory in different scenarios for classes of life distributions based on the MTTF function where the probabilities $\bar{P}_k$ of surviving the first k shocks are assumed to have discrete DMTTF, IMTTF and IDMTTF properties. The cumulative damage model of A-Hameed and Proschan [1] is studied in this context and analogous results are established. Weak convergence and moment convergence issues within the IDMTTF class of life distributions are explored. The preservation of the IDMTTF property under some basic reliability operations is also investigated. Finally we show that the intersection of IDMRL and IDMTTF classes contains the BFR family and establish results outlining the positions of various non-monotonic ageing classes in the hierarchy.

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