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    Distribution loss allocation for radial systems including dgs

    , Article IEEE Transactions on Power Delivery ; Vol. 29, issue. 1 , 2014 , pp. 72-80 ; ISSN: 08858977 Ghofrani-Jahromi, Z ; Mahmoodzadeh, Z ; Ehsan, M ; Sharif University of Technology
    2014
    Abstract
    Due to the liberalization of the electricity market and the introduction of distributed generation (DG), the importance of distribution loss allocation (LA) has increased. This paper presents a new method for distribution power LA in radial systems. The proposed method, which is based on the results of power flow and considers active and reactive power flows of lines for LA, is composed of three steps. In the first step, starting from the source nodes (i.e., the nodes whose generation is more than their load), the power loss allocated to all nodes is calculated and then the power loss allocated to the loads connected to each node is obtained. In the next step, the total power loss is... 

    Utilization of analytical hierarchy process in contingency ranking

    , Article 2009 IEEE/PES Power Systems Conference and Exposition, PSCE 2009, Seattle, WA, 15 March 2009 through 18 March 2009 ; 2009 ; 9781424438112 (ISBN) Abedi, M ; Ehsan, M ; Ghofrani Jahromi, Z ; Masjed Jamei, M ; Sharif University of Technology
    2009
    Abstract
    Contingency screening and ranking is one of the most important issues for security assessment in the field of power system operation. The objective of contingency screening and ranking is to quickly and accurately select a short list of critical contingencies from a large list of potential contingencies and rank them according to their severity. Then suitable preventive control actions can be implemented considering contingencies that are likely to affect the power system performance. In this paper a novel approach is presented for contingency ranking based on static security assessment (SSA). This method uses weighted performance index with the application of Analytical Hierarchy Process... 

    Loss Management in Smart Distribution Systems

    , Ph.D. Dissertation Sharif University of Technology Ghofrani Jahromi, Zeinab (Author) ; Ehsan, Mehdi (Supervisor)
    Abstract
    One of the topics that has been given great consideration after restructuring and smart grid emergence, is loss management. This subject is specifically important in distribution systems, which have been reported to have 70% of the total loss in power systems. In this thesis, distribution loss is studied and its affecting factors are analyzed. Then loss optimization and loss cost allocation to distribution consumers are studeid. In order to acheive these two goals, it is neccessary for the distribution system to have the capabilities of a smart grid. The subjectof distribution reconfiguration is duiscussed as one of the loss reduction methods. Traditional reconfiguration problem trend... 

    Cause-and-effect relationships affecting distribution loss management

    , Article IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT Europe, 11 October 2010 through 13 October 2010 ; October , 2010 ; 9781424485109 (ISBN) Ghofrani Jahromi, Z ; Ehsan, M ; Masjed Jamei, M ; Sharif University of Technology
    2010
    Abstract
    There are a lot of parameters which are decisive in distribution loss management, such as demand value, energy price, etc. In this paper the cause-and-effect relationships among some of these variables are clearly described. The study demonstrates how a variable in the model will change, if an alteration in one of the other variables occurs. The power system variables considered in this study include energy and loss prices, generation and demand values, distribution loss, distribution system age, number of customers connected to the smart grid, distribution network revenue, and so forth. The smart grid impacts can be studied from two different aspects: 1) the communication infrastructure... 

    From loss allocation to loss cost allocation: a comparative study of different loss cost allocation methods

    , Article International Transactions on Electrical Energy Systems ; Volume 23, Issue 4 , 2013 , Pages 586-600 ; 20507038 (ISSN) Ghofrani Jahromi, Z ; Ehsan, M ; Fotuhi Firuzabad, M ; Parvania, M ; Sharif University of Technology
    2013
    Abstract
    As a high proportion of the total generated electricity energy and the power system costs is due to the power losses in lines, allocating the loss and associated cost to the system loads and generating units is a substantial issue in deregulated power systems. The procedure to accomplish this cost allocation is designated as 'loss cost allocation' (LCA). So far, a number of LCA methods have been proposed for transmission networks. A few papers have compared different loss allocation methods, which are the methods which calculate the loss (and not necessarily the loss cost) allocated to the loads and generating units. However, this paper presents a comparative study of LCA methods. In this... 

    Optimal topological design of power communication networks using genetic algorithm

    , Article Scientia Iranica ; Volume 20, Issue 3 , 2013 , Pages 945-956 ; 10263098 (ISSN) Jahromi, A. E ; Rad, Z. B ; Sharif University of Technology
    2013
    Abstract
    An electric power supply is the backbone of development in advanced as well as in developing economies. An integral part of ensuring a secure power supply system is a power communication system. Due to the high and sustained performance requirements of power communication systems, electric companies prefer to construct their own communication networks privately rather than relying solely on a public communication system. The focus of this paper is on the optimal topological design of a power communication network. Based on advanced optimization models in public communication networks, and taking into account the specific Quality of Service, as demanded by various applications, such as... 

    Design of a Nonlinear Controller for a Bioreactor

    , M.Sc. Thesis Sharif University of Technology Ghofrani, Parisa (Author) ; Shahrokhi, Mohammad (Supervisor)
    Abstract
    Biotechnology is one of the fields that has had great advances in the past decades, and therefore controlling biological processes (bioreactors) is considered as an important issue. The purpose of current thesis is designing an adaptive controller for a bioreactor by considering input constrain and proving the stability of closed loop. A standard bioreactor has been chosen for this purpose. First a non-adaptive controller has been designed. Then an adaptive controller is designed and implemented on a bioreactor in the presence of input constraint, because in practice the system parameters are unknown. Finally by applying disturbance to the system, it has been shown that the proposed control... 

    Energy, exergy, exergoeconomics, and exergoenvironmental assessment of three brine recycle humidification-dehumidification desalination systems applicable for industrial wastewater treatment

    , Article Energy Conversion and Management ; Volume 205 , 2020 Ghofrani, I ; Moosavi, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Using zero liquid discharge systems is one of the efficient methods to reduce the negative environmental impact of the brines of the desalination systems and also to recycle the industrial wastewaters for reuse. Due to the simple fabrication process, low maintenance cost, intensive to inlet water quality, and the ability to use renewable and low-grade-heat, modified humidification-dehumidification systems may be a proper choice for the zero liquid discharge applications. Thus, in the present study, the energy, exergy, exergoeconomic, and exergoenvironmental assessment of three advanced brine recycle humidification-dehumidification systems for zero liquid discharge operation are... 

    Brine elimination by hybridization of a novel brine-recycle bubble-column humidification-dehumidification system with a multiple-effect distillation system

    , Article Energy Conversion and Management ; Volume 217 , 2020 Ghofrani, I ; Moosavi, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Over the past decades, drastic growth in the installed capacity of seawater desalination systems has increased the energy consumption and brine discharge to the environment. However, using renewable energies and zero liquid discharge systems for minimizing these challenges is limited due to the higher fresh water cost of the systems rather than that of the conventional systems. In this research, a bubble-column humidification-dehumidification zero liquid discharge system is coupled with a multiple-effect distillation/vapor compression system in a novel way to overcome the high water cost of conventional zero liquid discharge systems. Further, the base system and the solar-powered system is... 

    Thermodynamic and Economic Study of the Performance Improvement of Hybrid Desalination Plants

    , Ph.D. Dissertation Sharif University of Technology Ghofrani, Iraj (Author) ; Mousavi, Ali (Supervisor)
    Abstract
    In the present study, for cost-effective brine elimination of desalination plants, a hybrid system consisting of a multiple-effect distillation unit and a humidification-dehumidification unit is proposed. The development process of the hybrid system was carried out in two main steps: 1) evaluation of electricity-driven and heat-driven humidification-dehumidification brine concentrators 2) redesigning the humidification-dehumidification unit according to the results of step one and hybridization the unit with a multiple-effect distillation system. All the steps are assessed using the energy, exergy, exergoeconomics, and exergoenvironmental tools.Among the three heat-driven and... 

    Robust and efficient zero liquid discharge design strategy using four novel desalination systems: A comprehensive 4E assessment

    , Article Journal of Cleaner Production ; Volume 310 , 2021 ; 09596526 (ISSN) Ghofrani, I ; Moosavi, A ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Discharging unconventional water sources having a high content of inorganic compounds is extremely destructive to the environment. In this research, four novel semi-open-air and closed-air configurations of brine-recycle humidification-dehumidification (BRHDH) systems with zero liquid discharge (ZLD) approach are presented to treat unconventional waters cost-effectively. Bubble-column humidifiers and dehumidifiers are used to have a low initial expenditure, and system multi-staging is implemented to reduce the operating expense of the configurations. The configurations are evaluated for high saline brine treatment using comprehensive energy, exergy, exergoeconomic, and exergoenvironmental... 

    Simulation and Analysis of the Coolant Mixing Test within the Reactor Pressure Vessel of BNPP Using ANSYS CFX 18.0

    , M.Sc. Thesis Sharif University of Technology Khalvandi, Mohammad (Author) ; Ghofrani, Mohammad Bagher (Supervisor)
    Abstract
    Various factors, such as increasing or decreasing the heat removal from the initial circuit, or increasing the flow rate of the cooling fluid in the reactor, causes the phenomenon of the coolant mixing in the PWR reactors. In this project, the thermohydraulic test of coolant mixing has been simulated in the pressure vessel of the Bushehr nuclear reactor. In this test, the mixing of the coolant caused by the reduction of heat removal from the primary circuit by the secondary circuit is investigated. In this case, the primary circuit temperature increases in the loop where the heat removal is reduced. The most important consequence of this event is the reactivity changes at the core of the... 

    Simulation of Loop Connection of RCPs during Commissioning Test of BNPP Using RELAP 5 Code to Two or Three Operating Ones

    , M.Sc. Thesis Sharif University of Technology Zeynalian, MirHadi (Author) ; Ghofrani, Mohammad Bagher (Supervisor)
    Abstract
    In order to ensure the safety of the plants, a set of commissioning tests based on international standards for nuclear power plants is carried out before operation. In this research, one of the Bushehr power plant commissioning tests, the loop connection primary circuit cooling pump test, was simulated using the RELAP5 code. In this test, the effects of loop connection primary circuit pumps on the thermohydraulic parameters and the eneterance of test-related systems was evaluated. After simulating the systems related to the test and extracting the results of the stable state, were evaluated the transient results was obtained with the experimental results of the test of loop connection the... 

    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 Khorrami, Vahid (Author) ; 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... 

    Probabilistic Safety Assessment of A UF6 Production Process

    , M.Sc. Thesis Sharif University of Technology Ebrahimi, Behrooz (Author) ; Ghofrani, Mohammad Bagher (Supervisor)
    Abstract
    Identification of different hazards in a UF6 production process, and evaluation of the risk originated from these hazards is the main objective of this project. A number of hazards are present in a typical UF6 production process, such as leakage of chemical gases like HF and F2 and also radioactive UF6 gas release. In order to evaluate risk due to these hazards, probabilistic approach has been used. Due to lack of probabilistic safety criteria (PSC) for chemical releases, only for UF6 gas release risk assessment has been done. As a first step in PSA of this process eight groups of initiating events have been identified using HAZOP study, and for each initiating event, event tree analysis... 

    Model-Based Simulation of Surge and Active Controller Design of an Industrial Centrifugal Compressor applied in Gas Compression Systems

    , M.Sc. Thesis Sharif University of Technology Khodaparast, Pooya (Author) ; Ghofrani, Mohammad Bagher (Supervisor)
    Abstract
    Efforts to model and control surge, as the underlying instability of centrifugal compressors, were conducted. Of the three major instabilities in compressors, namely chokage, stall and surge, the latter has a significant role in limiting the available range of operation in centrifugal compressors, which are the most common devices for the transportation of Natural gas. The customary method to circumvent surge, which if occurred, could impose severe, catastrophic and irreversible damages to the machine, is to avoid the zones in which it is likely to develop by means of a recycling system. These often called "surge avoidance" or "surge prevention" schemes have the benefit of high reliability,... 

    Thermal Hydraulic Analysis of Prismatic Htgr with Natural Convection Using Porous Media Approach (in Case of Lose of Forced Circulation Accident)

    , M.Sc. Thesis Sharif University of Technology Golshanee, Masoud (Author) ; Ghofrani, Mohammad Bagher (Supervisor)
    Abstract
    In this study, the thermal-hydraulic analysis of prismatic HTGR’s core with natural convection has been studied using porous media approach. VHTR are the new generation reactors which due to special neutron and thermo physical properties have highly inherent safety. In lose of forced circulation accident, decay heat is transferred from core to pressure vessel wall and then to water tubes in concrete wall at reactor cavity with conduction, convection and radiation automatically. In this case the high volume of decay heat is stored in graphite block with high thermal capacity and is prevented the instantaneous temperature rising.
    The aim of this study is justifying inherent safety of HTGR... 

    Experimental Investigation on Laminar Forced Convection Heat Transfer of Ferrofluids Under an Alternating Magnetic Field

    , M.Sc. Thesis Sharif University of Technology Ghofrani, Ali (Author) ; Shafii, Mohammad Behshad (Supervisor)
    Abstract
    This research study presents an experimental investigation on forced convection heat transfer of an aqueous ferrofluid flow passing through a circular copper tube in the presence of an alternating magnetic field. The flow passes through the tube under a uniform heat flux and laminar flow conditions. The primary objective was to intensify the particle migration and disturbance of the boundary layer by utilizing the magnetic field effect on the nanoparticles for more heat transfer enhancement. Complicated convection regimes caused by interactions between magnetic nanoparticles under various conditions were studied. The process of heat transfer was examined with different volume concentrations... 

    Probabilistic Safety Assessment (PSA) of Inadvertent Opening Safety Valve of Pressurizer (SVP) Using SAPHIRE Code

    , M.Sc. Thesis Sharif University of Technology Kordalivand, Saeid (Author) ; Ghofrani, Mohammad Bagher (Supervisor)
    Abstract
    Inadvertent opening safety valve of pressurizer (SVP) is one of the most common initiator events in Booshehr nuclear reactors with occurrence frequency of 1.1E-0.2. This event has the third rank in initiator event among 16 other events (Loop and Compensated LOCA were ranked as first and second respectively). So special attention must be paid to SVP and the operators need to have specific trainings on this matter. In this thesis, the SVP as initiator event is being considered and the sequence which lead to core damage (CD), according to design informations is being modeled moreover the qualitative and quantitative analysis is carried out. In the modeling process we have used the SAPHIRE... 

    Development of an Effective Method to Support Severe Accident Management in Bushehr Nuclear Power Plant

    , Ph.D. Dissertation Sharif University of Technology Saghafi, Mahdi (Author) ; Ghofrani, Mohammad Bagher (Supervisor)
    Abstract
    Following Three Mile Island (TMI) accident in 1979, first severe accident (SA) in Nuclear Power Plants (NPPs), Accident Management Support Tools (AMSTs) were developed and installed in a number of NPPs. Lessons learned from Fukushima accident highlighted importance of Accident Management (AM) in mitigation severe radiological consequences after a SA and suggested reconsiderations of AM program which in turn created the need for AMSTs adaption and modernization. An efficient AMSTs should have the following principal capabilities: (1) Identification of accidents and diagnosis of the plant damage state (PDS), (2) Prediction of accident progress path and (3) Source term analysis and prediction...