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Online Monitoring and Condition Assessment of Power Circuit Breakers in Transmission Network to Enhance their Reliability through Maintenance Scheduling
, Ph.D. Dissertation Sharif University of Technology ; Vakilian, Mehdi (Supervisor) ; Niayesh, Kaveh (Co-Advisor)
Abstract
Maintenance management of power system components has been always one of the main challenges among the power system operation concerns. Experiencing the fast developments in power industries, and the power networks rapid expansions (as a consequence of power system energy consumpsion growth) while utilities have limitations on their annual investment budgets and the operational costs. Therefore, a more cost-effective maintenance plan is searched for. Various types of maintenance have been nowadays implemented in power systems, all over the world. Among them, reliability-centered maintenance and condition-based maintenance (CBM) can be addressed. Circuit breakers (CBs) from long ago are...
A practical approach on optimal RTU placement in power distribution systems incorporating fuzzy sets theory
, Article International Journal of Electrical Power and Energy Systems ; Volume 37, Issue 1 , 2012 , Pages 31-42 ; 01420615 (ISSN) ; Dehghanian, P ; Sharif University of Technology
2012
Abstract
Supervisory control and data acquisition (SCADA) infrastructures have so far been brought into the huge amount of focus since the need for a more reliable power system accosting with the catastrophic events of interruptions has been raised. Hence, benefiting from an automation technology which can remotely monitor and coordinate commands to enable immediate response and switching are obviously inevitable. This paper outlines an implementable method in response to the goal of placement of remote terminal units (RTUs) which are in charge for data acquisition and control in a power distribution system. In this light, a new practical methodology based on the robust decision making (DM) method,...
A probabilistic approach for remote terminal unit placement in power distribution systems
, Article INTELEC, International Telecommunications Energy Conference (Proceedings) ; 2011 ; 02750473 (ISSN) ; 9781457712494 (ISBN) ; Dehghanian, P ; Karami, G ; Sharif University of Technology
2011
Abstract
This paper investigates a reliability-centered approach for the placement procedure of remote terminal units (RTUs) in power distribution systems. Entire attempt is contributed to incorporate the practical aspects interrelated with the problem, e.g. the accessibility to the candidate substations, the load point criticality, as well as the load probabilistic behavior and consequently the inevitable variation in the electricity price. The placement process is done through an optimization problem wherein the common reliability indices, as the decisive factors in the placement process, are going to be minimized. The approach is successfully applied to a real power distribution feeder of Iran's...
Circuit-breaker automated failure tracking based on coil current signature
, Article IEEE Transactions on Power Delivery ; Vol. 29, issue. 1 , February , 2014 , pp. 283-290 ; ISSN: 08858977 ; Vakilian, M ; Niayesh, K ; Lehtonen, M ; Sharif University of Technology
2014
Abstract
The online condition assessment of circuit breakers (CBs) has been increasingly requested by power utilities in recent years. Trip and close coil current (CC) signature is an effective and noninvasive parameter in CB online condition monitoring. This paper gives an insight into the impacts of the various failures on the coil current waveform, as well as on the CB operation time. The failures and their causes are categorized based on the outcome of these investigations. Finally, a new algorithm using trip/close CC is proposed to detect the mode and cause of CB incipient failures. In this study, the CC patterns are acquired by measurements carried out on (healthy and faulty) CBs of 72.5-kV and...
Priority Assessment of Online Monitoring Investment for Power System Circuit Breakers - Part I: Qualitative-Quantitative Approach
, Article IEEE Transactions on Power Delivery ; Volume 28, Issue 2 , 2013 , Pages 928-938 ; 08858977 (ISSN) ; Vakilian, M ; Niayesh, K ; Lehtonen, M ; Sharif University of Technology
2013
Abstract
Recognition of the circuit-breaker's (CB) vital role in reliable operation and protection of power systems (i.e., during energization, disconnecting loads, and clearing faults), helps to understand the requirement and importance of its maintenance management as well as maintenance scheduling. Condition-based maintenance (CBM), employing online monitoring (OLM) of CBs, has been long reported as the most practical maintenance policy on the power system CBs. There are a large number of CBs in a power system to be monitored; however, to address the financial limitations for OLM implementation (in utilities), a method will be proposed to find the most critical breakers for enforcing effectively...
Priority assessment of online monitoring investment for power system circuit breakers-part II: Determination of optimum number
, Article IEEE Transactions on Power Delivery ; Volume 28, Issue 3 , 2013 , Pages 1440-1446 ; 08858977 (ISSN) ; Vakilian, M ; Niayesh, K ; Lehtonen, M ; Sharif University of Technology
2013
Abstract
The proper and reliable operation of circuit breakers (CBs) directly affects the reliability and continuity of electricity services in a power systems. Condition-based maintenance (CBM) is the best economic CB maintenance strategy through its online monitoring (OLM) possibilities. Since there is a large number of CBs in a power system, to equip all CBs with OLM systems is not economically justifiable however. This paper, as the second part of a two-part paper, presents an effective optimization framework to find the optimal number of CBs to be monitored online as the kernel of CBM process. To prove its feasibility, the proposed approach is applied to the IEEE Roy Billinton Test System, which...
Critical component identification in reliability centered asset management of power distribution systems via fuzzy AHP
, Article IEEE Systems Journal ; Vol. 6, issue. 4 , 2012 , p. 593-602 ; ISSN: 19328184 ; Fotuhi-Firuzabad, M ; Bagheri-Shouraki, S ; Razi Kazemi, A. A ; Sharif University of Technology
2012
Abstract
Confronted with the power system restructuring trend reforming the past-regulated power systems, the need for a narrower insight on the costly maintenance strategies seems imperative. It falls within the realm of reliability centered maintenance to enhance the cost effectiveness of power distribution maintenance policies. From a practical point of view, this paper devises a novel approach on the basis of the analytical hierarchical process (AHP) accompanied by fuzzy sets theory to determine the most critical component types of distribution power systems to be prioritized in maintenance scheduling. In the presence of many qualitative and quantitative attributes, fuzzy sets can effectively...
Innovative Team Climate, Teamwork Quality and Team Performance in Software Development Teams
, M.Sc. Thesis Sharif University of Technology ; Kermanshah, Ali (Supervisor)
Abstract
In this dissertation, our aim is to evaluate a model linking “Teamwork Quality” and “Innovative Team Climate”. Teamwork Quality is defined as the quality of interactions among team members that includes six dimensions: “Communication”, “Coordination”, “Balance of Contribution”, “Mutual Support”, “Effort”, and “Cohesion”. Innovative Team Climate refers to shared perceptions of team policies, practices and procedures in support of innovation. This construct is composed of four dimensions: “Vision”, “Participation Safety”, “Task Orientation”, and “Support of Innovation”. Firstly, we hypothesized that there are positive relations between Innovative Team Climate and Teamwork Quality itself and...
Performance Simulation of HCCI Engine Equipped with Direct Injection System
, M.Sc. Thesis Sharif University of Technology ; Mozafari, Ali Asghar (Supervisor)
Abstract
HCCI engines have lower NOX and PM emissions and higher thermal efficiency compared to spark ignition engines. But these engines have some deficiencies which up to now have prevented their widespread employment. These engines have not been very successful at high loads and speeds and in these conditions normally produce high pollution and noise. In order to solve this problem the present research proposes to equip the HCCI engines with fuel injection system so that at low loads and speeds operate at HCCI engine mode and at loads and speeds higher than pre-set limits, use the fuel injection system in order to operate at a combined HCCI and compression ignition engine mode and provide a...
Mild Hybrid Vehicle Performance
, M.Sc. Thesis Sharif University of Technology ; Mozafari, Ali Asghar (Supervisor)
Abstract
Many studies on hybrid vehicles have been done in the past few years. The Full hybrid vehicles need a large number of batteries creating up to 300V to meet the required voltage of electric motor. The size and weight of the batteries cause some problems. This research investigates the mild hybrid vehicle. This vehicle includes a small electric motor and a high power internal combustion engine. In most cases the car’s driving force is created by internal combustion part. A small electric motor, which can operate as engine starter, generator and traction motor, is located between the engine and automatically shifted multi-gear transmission (gearbox). The clutch is used to disconnect the gearbox...
Prediction of Homogeneos Charge Compression Ignition (HCCI) Engines Performance Using Multi-Zone Model
, M.Sc. Thesis Sharif University of Technology ; Mozafari, Ali Asghar (Supervisor)
Abstract
Some researches have been carried out in the last 20 years in order to increase the present IC engines thermal efficiency and their optimum performance. (HCCI) engine is viewed as a combination of spark-ignition (SI) and compression-ignition (CI) engines. This is because HCCI engines use premixed fuel/air mixture like SI engines and have auto ignition combustion after the mixture is compressed like CI engines. Control of combustion and ignition timing are the main challenges of these engines. Ignition delay, compression ratio, fuel air equivalence ratio and intake temperature and pressure are considered to be the most effective parameters on HCCI combustion.HCCI engines have great potentials...
Prediction of HCCI Engine Performance Using Blend of H2 and HC Fuel
, M.Sc. Thesis Sharif University of Technology ; Mozaffari, Ali Asghar (Supervisor)
Abstract
The idea of improving performance of internal combustion engines has always been important for researchers and manufacturers. In recent decades, due to limited resources of fossil fuels and introduction of vehicle emission regulations, researchers have undertaken more efforts to achieve goals such as increased horsepower, reduced fuel consumption and pollutant emissions reductions. Homogeneous charge compression ignition engine is a modern and efficient design that has attracted attention of many researchers. In[[ these engines, homogenous mixture of fuel and air enters into the combustion chamber and with a mechanism of self ignition, produces more power and has less fuel consumption...
“Prediction of Stratified Charge Engine Performance Using HC Fuels”
, M.Sc. Thesis Sharif University of Technology ; Mozafari, Ali Asghar (Supervisor)
Abstract
The partially stratified charge (PSC) approach involves micro-direct-injection of pure fuel or a fuel air mixture, to create a rich zone in the region around the spark plug. A theoretical model is presented in this research to predict ignition delay and combustion process in partially stratified charge engine. It considers flame progress through rich and lean regions. Step by step calculations will be carried out in both regions. The process continues to the point where all the fuel is burned. At each step for one degree rotation of the crank shaft, there is a change in cylinder volume and mole fraction burned due to burning of a fraction of the mixture. Considering heat transfer from the...
Electric-field-induced Response of Charged Droplets in Uncharged Hydrogels
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
The electric field induced response of a charged droplet in an uncharged gel is calculated theoretically. For modeling, the gel is considered as a soft porous solid that is saturated with a Newtonian electrolyte and modeled as a continuum that contains 3 phases: a porous, soft and compressible solid, an incompressible Newtonian fluid and the ions inside fluid. Droplet is modeled as a charged incompressible Newtonian fluid immiscible with the gel. The droplet-gel interface is considered as a surface with electrostatic potential ζ . After obtaining governing equations, they solved by using perturbation methodology and linear superposition. Boundary conditions, especially at the droplet-gel...
Janus Silica Nanoparticles and Their Application for Enhanced Oil Recovery
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
Nanoparticles can be applied as chemical agent in enhnaced oil recovery like surfactants and polymers. One of nanoparticles usefull capabilities is modification of their surface. This research investigates this capabilty of nanoparticles in enhanced oil recovery. Surface modification of nanoparticles with both agents can bring new abilities to these materials. Here surface of silica nanoparticles is modified by hydrophilic agent comprising PEG groups, hydrophobic agent comprising propyl group and both agents. FT-IR tests showed that grafting of modifiyng agents on surface of nanoparticles is well done. To investigate effect of nanoparticles surface modification on nanoparticles capability in...
Synthesis of Amphiphilic Nanoparticles with Different Alkyl Chains and their Application in Enhanced Oil Recovery
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
Important features of the nanoparticles properties are their high superficial area and being able to reform their surface. In this study, the repairable property used to reform surface of silica nanoparticles (Those are used more frequently than other nanoparticles). Repairing of surface are doing to use nanoparticles as a surface-active material in enhanced oil recovery. Silane compounds with different chain length are used to create hydrophobic nanoparticles and PEG compounds are used to create hydrophilic nanoparticles. Also amphiphilic nanoparticles are created with a combination of both hydrophilic and hydrophobic compounds. To investigate the usefulness of nanofluids are made up of the...
Design and Fabrication of a Microfluidic System Based on Dielectrophoresis for Enrichment and Separation of Bioparticles
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
The main purposes of this project are simulation, design, and fabrication of a microfluidic system based on dielectrophoresis (DEP) exploiting AC voltages for separation of microparticles. Generally, this project can be divided into two parts. First, the engineering section including design and fabrication of microchip, and second biological samples preparation for investigating the system performance. The main advantages of proposed system are eliminating joule heating, a significant problem in insulating based dielectrophoresis systems, overcoming problems related to metal contamination in biological samples, the main problem of conventional dielectrophoresis platforms, and removing...
Microfluidics Biological Separation
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
The main goals of this research are design, simulation, and fabrication of a microfluidic system working based on dielectrophoresis. This research divided into two different parts, the first of which is the simulation of a microfluidic system, and second of which is an attempt for fabrication of microfluidic system. For the fabrication of the microfluidic system, different methods were used. In the simulation part, the enrichment of different particles was investigated, and the effects of different parameters on the enrichment were assessed. It was observed that as flow rate increases, the enrichment amount diminishes. Furthermore, as the microfluidic depth decreases, the enrichment amount...
The Impact of Temperature on Surface Activity and Stability of Surface Modified Nano Particles
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
Surface modification is an important property of nano particles. In this project surface of silica nano particles modified with hydrophobic and hydrophilic groups to imrprove surface activity of nano particles. Purpose of this project is to study surface activity of surface modified silica nano particles in different temperatures from 20 to 70 degree centigrade. Also effect of salt and time on the surface activity is studied. At first nano particles modified just with haydrophobic groups and then just with hydrophilic groups (hydrophobic and hydrophilic nano particles) and after that, the surface modification done with both hyadrophilic and hydrophobic groups (amphiphilic nanoparticles)....
The Investigation of Adsorption Desulfurization of Ethyl Mercaptan by Microfluidic Technology
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
In recent years, desulfurization has received much attention due to its devastating environmental effects. The existence of sulfur compounds has effects such as corrosion, poisoning of catalysts, reduction of heat of combustion and reduction of price. Sulfur compounds in hydrocarbon fuels also produce sulfur oxides caused by combustion then they enter the atmosphere, and cause acid rain. Acid rain dissolves building materials, poisons lakes, and destroys forests. Therefore, removing sulfur or converting it to less harmful substances is one of the most important processes in refineries. The method studied in this research is the use of adsorption desulfurization method by microchannel which...