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reliability-evaluation
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Total 55 records
Probabilistic Placement of Phasor Measurement Units (PMUs) for Power Network Observability
, Ph.D. Dissertation Sharif University of Technology ; Fotuhi Firuzabad, Mahmoud (Supervisor) ; Shahidehpour, Mohammad (Co-Advisor)
Abstract
Wide-area measurement system (WAMS), which is enabled by broad installation of phasor measurement units (PMUs), is a novel solution for the secure and reliable operation of modern power systems. The adequate number and appropriate location of PMUs has been introduced as a challenging research area in recent years. This dissertation is the first effort to assess the cost/worth analysis of WAMS design and PMU locationing in a probabilistic manner. In the studies conducted here, power network monitoring and control associated with the energy management system (EMS), among miscellaneous applications of WAMS, have been taken into consideration. First, the conventional deterministic definition of...
Application of PSA Methods in the Reliability Analysis of EPSS of Busherhr NPP in case of Station Black Out
, M.Sc. Thesis Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor)
Abstract
LOOP accident is one of the most important accidents in NPPS and it leads to loss of power supply of the RCP pumps which are the main pumps of primary circuit. Subsequently trip of the rector occurs. In safety analysis, concerning worst conditions, assumes that after a small period of time, main generator of plant stops working and loss of AC power supply of all power plant loads including safety systems ocures. To control of this accident, it’s necessary to startup and load backup power supply system (EDGs) for at least one safety channels, if not, the accident moves forwards and becomes S.B.O accident which is more important accident that ends to core damage because of stops working of all...
Designing the Structure of a PHEV Aggregator in Multi-Carrier Energy Environment
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour Tehrani Fard, Ali (Supervisor) ; Fotuhi Firuzabad, Mahmoud (Supervisor)
Abstract
Large penetration of electric vehicles and distributed generation (DG) resources in upcoming years will change the future vision of distribution networks from some passive load points into active ones. The imposed load of electric vehicles charging has caused many new challenges in operation and planning studies of distribution network. In contrast, the abilities of electric vehicles in feeding back power into the network (V2G programs) has attracted attention from grid operators and also vehicles owners. So, the problem of managing charging and discharging behaviors of electric vehicles has been introduced as a hot research topic in recent year. This dissertation as the first effort in this...
Reliability and Economic Evaluation of Power System with Wind Power
, M.Sc. Thesis Sharif University of Technology ; Oraee Mirzamani, Hashem (Supervisor)
Abstract
The demand for electrical energy is increasing. The main source of energy at this moment is fossil fuels. High price, great amount of pollution, uneven distribution and global warming are major disadvantages of fossil fuels. Using renewable resources can tackle these issues. Hence, the demand for renewable energy are highly increased. The wind energy is one type of renewable energy. Increasing the wind power penetration impairs the functionality of power system and causes the environmental issues. In order to have a stable power system this effect should be investigated thoroughly. Due to the inherent uncertain characteristics of wind energy, it is desirable to determine the characteristics...
Identifying and Ranking Supply Chain Risk Factors and Calculating Reliability in 3 Level Supply Chain
, M.Sc. Thesis Sharif University of Technology ; Eshraghnia Jahromi, Abdolhamid (Supervisor)
Abstract
Since 1990, supply chains get affected by business environment changes and become more vulnerable. Changes such as globalization, decrease of inventory levels, out sourcing, etc. in this thesis after reviewing some paper, researches are categorized in 8 group. Then 30 risk factor identified from this papers. Because of basic differences in industries and different importance of risk factors in them, a case was studied in one industrial area and risk factors was evaluated in a two-step evaluation. Eventually some advices presented for increasing reliability for that case
Reliability Evaluation of Smart Distribution Grids
, Ph.D. Dissertation Sharif University of Technology ; Fotuhi Firouzabad, Mahmoud (Supervisor) ; Lehtonen, Matti (Supervisor)
Abstract
The term “Smart Grid” generally refers to a power grid equipped with the advanced technologies dedicated for purposes such as reliability improvement, ease of control and management, integrating of distributed energy resources and electricity market operations. Improving the reliability of electric power delivered to the end users is one of the main targets of employing smart grid technologies. The smart grid investments targeted for reliability improvement can be directed toward the generation, transmission or distribution system level. However, radial operating status, aging infrastructures, poor design and operation practices and high exposure to environmental conditions have caused the...
Continues Risk Assessment by Exploiting Artificial Intelligence
, M.Sc. Thesis Sharif University of Technology ; Rajabi, Abbas (Supervisor) ; Rashtchian, Davoud (Supervisor)
Abstract
The Fourth Industrial Revolution brought about a fundamental change in the system of management and production, especially in the field of industry, which was accompanied by the development of technology in the fields of artificial intelligence, robotics, nanotechnology and biotechnology. In line with these changes, the industry needs a new method to evaluate the reliability of operational equipment using artificial intelligence and intelligent systems, which aims to optimize the balance between a variety of repair methods with the possibility of timely replacement of parts. In this new method, the life of the parts is increased and the unplanned maintenance costs and labor are reduced. One...
Codification of Reliability Evaluation Software in UAVs Industry
, M.Sc. Thesis Sharif University of Technology ; Banazadeh, Afshin (Supervisor)
Abstract
In every modern society, the engineers and technical managers are in charge of planning, designing, manufacturing and utilizing the simplest products to the most complex systems. This shows the importance of reliability management in engineering systems. Inattention to the reliability of such systems leads to the difficulty or even impossibility in planning or utilizing them. Malfunction of products and systems results in disruption in different levels and can be regarded as a severe threat to society and environment.
Therefore, consumers and general public expect products and systems to be durable, reliable and safe. Thus, the main question is how safe and how reliable the system will...
Therefore, consumers and general public expect products and systems to be durable, reliable and safe. Thus, the main question is how safe and how reliable the system will...
Evaluation of Fault Tolerance for SRAM-Based FPGAs by Fault Injection into Configuration Bits
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
Reconfiguration, short development time and low cost have made Field Programmable Gate Arrays (FPGAs) an appealing option for digital circuit designers. Meanwhile, the occurrence of Single Event Upset (SEU) in configuration memory of SRAM-based FPGAs can change the implemented design inside the FPGA chip. Assessing reliability of FPGA-based designs against pernicious effects of SEU has long been a challenge. Several approaches can be used to evaluate the reliability of a given design. One important approach is injecting fault into the configuration memory of a device.The existing fault injection frameworks are specific in the property e.g. providing speed only, neglecting other properties of...
Security Analysis and Reliability Evaluation of Energy Internet
, M.Sc. Thesis Sharif University of Technology ; Rajabi Ghahnuyeh, Abbas (Supervisor)
Abstract
Due to the world's reliance on fossil fuels, the climate change situation has become more severe and has presented major challenges. One of the most promising growth avenues to address these issues in the medium to long term is widespread electrification based on renewable sources. However, this is only feasible if the energy infrastructure can support distributed and renewable energy sources without affecting the performance of the power grid. A grid is also necessary for energy systems in order to connect various technologies and guarantee proper integration of supply and demand for maximum efficiency. A novel idea called Energy Internet (EI) has been put forth to accomplish these goals,...
Fault tree analysis for reliability evaluation of an advanced complex manufacturing system
, Article Journal of Advanced Manufacturing Systems ; Volume 17, Issue 1 , March , 2018 , Pages 107-118 ; 02196867 (ISSN) ; Akhavan Niaki, S. T ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2018
Abstract
In this paper, minimal paths and cuts technique is developed to handle fault tree analysis (FTA) on the critical components of industrial robots. This analysis is integrated with the reliability block diagram (RBD) approach in order to investigate the robot system reliability. The model is implemented in a complex advanced manufacturing system having autonomous guided vehicles (AGVs) as material handling devices. FTA grants cause and effects and hierarchical properties to the model. On the other hand, RBD simplifies the complex system of the AGVs for reliability evaluation. The results show that due to the filtering of the paths in a manufacturing system for AGVs, the reliability is highly...
Modified branching process for the reliability analysis of complex systems: Multiple-robot systems
, Article Communications in Statistics - Theory and Methods ; Volume 47, Issue 7 , 2018 , Pages 1641-1652 ; 03610926 (ISSN) ; Akhavan Niaki, S. T ; Sharif University of Technology
Taylor and Francis Inc
2018
Abstract
Current design practice is usually to produce a safety system which meets a target level of performance that is deemed acceptable by the regulators. Safety systems are designed to prevent or alleviate the consequences of potentially hazardous events. In many modern industries the failure of such systems can lead to whole system breakdown. In reliability analysis of complex systems involving multiple components, it is assumed that the components have different failure rates with certain probabilities. This leads into extensive computational efforts involved in using the commonly employed generating function (GF) and the recursive algorithm to obtain reliability of systems consisting of a...
Mathematical methods of combining deterministic/probabilistic criteria in short-term generating reserve scheduling
, Article Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering ; Volume 218, Issue 2 , 2004 , Pages 69-75 ; 09544089 (ISSN) ; Fotuhi Firuzabad, M ; Sharif University of Technology
Professional Engineering Publishing
2004
Abstract
Probabilistic approaches generally base the design and operating constraints on the criterion that the risk of certain events must not exceed preselected limits. Many utilities still prefer to use deterministic techniques owing to the difficulty in interpreting a numerical risk index and the lack of sufficient information provided by a single index. This is especially true in the power system operating domain as existing probabilistic risk indices do not provide any assessment of the capacity reserve available during the course of system operation. A practical way to overcome these difficulties is to embed deterministic considerations into the probabilistic framework in the form of system...
Hybrid AC/DC microgrids flexible reliability index by using the axiomatic design concept
, Article IET Generation, Transmission and Distribution ; Volume 14, Issue 23 , 2020 , Pages 5456-5462 ; Doroudi, A ; Fotuhi Firuzabad, M ; Bashiri, M ; Sharif University of Technology
Institution of Engineering and Technology
2020
Abstract
With the capacity increase of large-scale DC renewable energy and DC loads, the reliability issues of hybrid AC/DC networks become increasingly prominent. On the other hand, a modern distribution network should also deliver power to individual customers based on their priority levels and the traditional reliability indices are not suitable for modern networks. Flexible reliability (FR) is a new concept that considers the loads' importance in the reliability evaluation of distribution grids. In this study, a novel comprehensive FR index is introduced for hybrid AC/DC networks. To determine the proposed index, power networks are modelled as a topological combination of edges and nodes. An...
Reliability evaluation in power distribution system planning studies
, Article 2016 International Conference on Probabilistic Methods Applied to Power Systems, PMAPS 2016 - Proceedings, 16 October 2016 through 20 October 2016 ; 2016 ; 9781509019700 (ISBN) ; Fotuhi Firuzabad, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In distribution system planning studies, reliability evaluation is performed during optimization procedure to calculate the interruption cost, DISCO's income and to check the viability of constraints related to reliability indices. In each iteration of the optimization algorithm a special plan is evaluated that is different from other plans. So the configuration and specification of the network which is one of the input information for reliability evaluation is changing continuously that makes difficulties for this evaluation. To solve these difficulties, this paper presents a systematic method for reliability evaluation in distribution planning studies. The proposed approach can be...
Impacts of remote control switch malfunction on distribution system reliability
, Article IEEE Transactions on Power Systems ; Volume 32, Issue 2 , 2017 , Pages 1572-1573 ; 08858950 (ISSN) ; Farajollahi, M ; Fotuhi Firuzabad, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
Remote control switches (RCSs) are often assumed to be fully reliable in reliability and cost/worth analyses. This assumption, however, overestimates their merits, thereby misguiding network owners about their optimal implementation. This letter extends the current reliability evaluation procedure to incorporate probability of RCS malfunctions. Then, the extended procedure is applied to a network equipped with a few RCSs. The numerical studies reveal that RCS malfunctions degrade their worth, which may even affect their optimal number and locations. © 1969-2012 IEEE
SOYA: SSD-based RAID systems reliability simulator
, Article 2016 International Conference on System Reliability and Science, ICSRS 2016, 15 November 2016 through 18 November 2016 ; 2017 , Pages 167-173 ; 9781509032778 (ISBN) ; Safaei, B ; Miremadi, S. G ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
The use of Solid State Drives (SSDs) has been increased in storage systems due to high performance and low power consumption. However, some inherent properties of SSDs result in different behavior for SSDs in comparison with Hard Disk Drives (HDDs). As an inherent property, the Bit Error Rate (BER) of SSDs increases, when the number of Program/Erase (P/E) cycles arises. This increment leads to two effects in an array of SSDs during its operation: (1) different BER on different SSDs of the system (SSD-variant BER), and (2) different BER in different time moments (time-variant BER). With respect to these two effects, the reliability evaluation of SSD-based RAIDs would be different from...
Reliability based joint distribution network and distributed generation expansion planning
, Article 2020 International Conference on Probabilistic Methods Applied to Power Systems, PMAPS 2020, 18 August 2020 through 21 August 2020 ; September , 2020 ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Pourghaderi, N ; Lehtonen, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
In this paper the reliability of distribution network is modeled in joint multistage expansion planning of distribution network assets and distributed generations (DGs). The imposed costs due to network reliability weakness are considerable in the distribution level. Therefore in the proposed model distribution network operator (DNO) considers the costs associated with load interruptions in the planning problem. In this regard, reliability evaluation of the network is modeled in the joint multistage distribution network expansion planning (MDNEP) problem in an integrated manner while the network topology is unknown until the planning problem is not solved. In the proposed joint MDNEP problem...
Reliability evaluation in microgrids with non-exponential failure rates of power units
, Article IEEE Systems Journal ; Volume 14, Issue 2 , 2020 , Pages 2861-2872 ; Fotuhi Firuzabad, M ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
This article explores the impacts of non-exponentially distributed failures on reliability of microgrids. Failure rate of some components such as power electronic converters is not constant, while they play a major role in microgrids. Consequently, their failure characteristics will affect the microgrid reliability. Hence, the conventional reliability evaluation approaches based on mean time to failure may introduce inaccurate inputs for decision making in planning and operation of microgrids. In this article, different approaches are employed for evaluating the reliability of microgrids with non-constant failure rates. The obtained results indicate that the system reliability remarkably...
Inverse reliability evaluation in power distribution systems
, Article IEEE Transactions on Power Systems ; Volume 35, Issue 1 , 2020 , Pages 818-820 ; Rastegar, M ; Allahbakhshi, M ; Fotuhi Firuzabad, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
In power distribution systems, sometimes, system reliability indices are available, where some components' reliability parameters are unknown. This letter presents the inverse reliability evaluation (IRE) problem in radial distribution systems to find unknown components' parameters from the known system reliability indices. To this end, a nonlinear system of equations is presented and solved. The solutions are analyzed in the RBTS bus 2 to verify the applicability of the proposed approach and to show the importance of the IRE problem. © 1969-2012 IEEE