HIGH SIDE VOLTAGE CONTROLLER TO IMPROVE PERFORMANCE AND VOLTAGE STABILITY OF A POWER SYSTEM /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 9
هبة عبد الحميد متولي خطاب( khatab.heba@yahoo.com - 01004151345 )
Synchronous generator, HSVC, AVR, PSS, Voltage stability, Voltage Droop Rate
This paper describes a high side voltage controller (HSVC) design, implementation and performance study for a synchronous generating unit connected to an infinite bus power system via a transformer and a double-circuit transmission line. In addition to enhance the system performance, the HSVC can improve power system voltage stability by adding supplemental control to conventional generator excitation system. The simulation results using detailed non-linear model for the system with: a conventional automatic voltage regulator (AVR), power system stabilizer (PSS), and applying HSVC, are obtained. These results illustrate the superiority of HSVC to enhance the system performance as well as its voltage stability when subjected to different disturbances.
Optimal Power Flow Control Based Shunt FACTS Devices Using PSO Algorithm /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 11
جمال عبد الوهاب مرسي( gamorsy@yahoo.com - 01003099394 )
optimal power flow, particle swarm optimization, FACTS
In this paper, an efficient and reliable evolutionary-based approach is employed to solve the optimal power flow (OPF) problem. This approach utilizes the global and local exploration capabilities of particle swarm optimization (PSO) to search for optimal setting of control variables for the OPF which is formulated as a nonlinear constrained objective optimization problem with both equality and inequality constraints. To illustrate how the proposed method has an efficient role, the standard IEEE 30-bus power system is studied and the PSO is used to minimize each of the total fuel cost, system power loss and voltage deviations. Two different types of FACTS devices are embedded with the test system, SVC and STATCOM, to achieve the objectives functions under certain constraints. The results show the effectiveness of STATCOM with optimal settings over the SVC with same conditions.
Optimal Power Flow Problem Solution Incorporating FACTS Devices Using PSO Algorithm /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 11
جمال عبد الوهاب مرسي( gamorsy@yahoo.com - 01003099394 )
optimal power flow, particle swarm optimization, SVC and UPFC.
This paper presents an efficient and reliable evolutionary-based approach to solve the optimal power flow (OPF) problem. To search the optimal setting of control variables for the OPF, which is formulated as a nonlinear constrained objective optimization problem with both equality and inequality constraints, particle swarm optimization (PSO) algorithm is used. The standard IEEE 30-bus power system is studied to illustrate how the proposed method has an efficient role. The objectives are minimizing the total fuel cost, system power loss, installation cost of FACTS and voltage profile improvement. Two different types of FACTS devices are incorporated with the test system, SVC and UPFC, to achieve the objective functions under certain constraints. Furthermore, the proposed method is used to determine the optimal location of FACTS controller. The results show the effectiveness of UPFC with optimal settings over the SVC under the same conditions. Also, the results illustrate the importance of determination of the best location of FACTS devices.
Fault Tolerant Of Three-Phase Inverter Fed Speed Sensorless Induction Motor Drive System /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 8
زكى محمد البربرى
: Induction motor drive, Current control Voltage source inverter (CCVSI), Fault tolerant, four-switch three phase inverter (FSTPI).Insulated Gate Bipolar Transistor (IGBT
This paper proposes an algorithm for fault tolerance of three-phase inverter fed speed sensorless control of three- phase induction motor drive system. The fault tolerance of inverter when one switch is open or one leg of six-switch inverter is lost is considered. The control of the drive system is based on indirect rotor field oriented control theory. Also, the speed estimator is based on model reference adaptive system (using stator current and rotor flux as state variables for estimating the speed). The fault tolerant algorithm is able to adaptively change-over from six switch inverter to four switch inverter topologies when the fault is occurred; also, it makes a smooth transition of the motor speed, torque and current when changing over from faulty condition to new healthy status which is (Four-Switch Three-Phase Inverter (FSTPI) topology), thus, the Six Switch Three-Phase Inverter (SSTPI) topology (pre-fault status) almostly retained. The proposed algorithm is simulated by using the MATLAB/SIMULINK package. The obtained results from the simulation model demonstrate the performance enhancement and good validity of the fault-tolerance control for speed sensorless induction motor drive system.
Vector Control of FSTP Inverter Fed Synchronous Reluctance Motor Based Maximum Torque Control /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 9
هيثم زكي عزازي( h_azazi@yahoo.com - 01066475518 )
Conventional Synchronous Reluctance motor; Four switch inverter; Vector control, Maximum torque control; Hysteresis current controller; Saturation and iron losses.
This paper presents a cost-effective vector control strategy for four switch three phase (FSTP) inverter fed a synchronous reluctance motor with conventional rotor (SynRM) drive. The reduction of the number of power switches from six to four improves the cost-effectiveness, volume-compactness and reliability of the three phase inverters. In this paper, a simulation model of the drive system is developed and analyzed in order to verify the effectiveness of the proposed approach. The application of vector control to a SynRM at maximum torque control (MTC) operation is presented with emphasis on the effects of saturation and iron losses are briefly considered. A PI controller is used to process the speed error. Two independent hysteresis current controllers with a suitable hysteresis band are utilized for inverter switches signals. A simplified steady-state d-q model including saturation and iron losses is presented. Simulation and experimental results show that the drive system provides a fast speed response and good disturbance rejection capability.
Comparison between linear and nonlinear control Strategies for Induction Motor /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 9
محمد عزت محمد إبراهيم( en.ezzat@yahoo.com - 01287671375 )
This paper presents a comparison of two different control strategies for Squirrel-Cage Induction Motor (IM): conventional Proportional-Integral (PI) controller and modern Sliding Mode Controller (SMC). Two control laws are proposed to control speed and rotor flux independently. Convergence analysis of the SMC, based on Lyapunov theory, is proved. Both strategies are investigated and simulated using MATLAB/Simulink under nominal case. Moreover, the robustness of both methods with respect to the parameters uncertainties is verified by significant simulation results. The study shows that nonlinear control strategy based Sliding mode technique possesses not only high-performance dynamic characteristics, but also robustness with respect to parameter variations and external load disturbances compared to PI controller.
Field oriented control, linear control, Non-linear control, PI controller, sliding mode controller, Speed controller, and Induction motor.
Experimental Investigation of Four Switch Three Phase Inverter Performance Fed Sensorless Speed Control of Induction Motor Drives /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 8
هيثم زكي عزازي( h_azazi@yahoo.com - 01066475518 )
Induction motor, Four switch inverter, Six switch inverter, Sensorless control, model reference adaptive system (MRAS) , total harmonic distortion(THD) and digital signal processor (DSP).
This paper presents an experimental investigation of four switch inverter performance fed three phase induction motor drives. The speed estimation based on fundamental wave models using model reference adaptive system as speed estimator technique. The motor is fed from four switch three phase inverter. A comparative study for sensorless speed estimation using four switch three phase inverter and six switch inverter is experimentally investigated. Also a comparison of system performance based on four switch inverter and conventional six switch inverter in terms of speed response and total harmonic distortion of stator currents is presented. Experimental results at different point of operations are presented verifying robustness of sensorless speed estimation at different load levels. Sensorless speed estimation based on four switch three phase inverter is quite acceptable considering its speed response.
Ballizing is a method of burnishing an internal diameter by forcing a precision ground steel or a tungsten carbide ball through a slightly undersized pre-machined hole. This plastic deformation process produces a smooth surface with favorable mechanical properties and negative residual stresses. The objective of this investigation is to determine the optimal setting of the ballizing parameters while ballizing 70/30 cu-zn brass alloy. The parameters considered are interference, wall thickness of the hole, number of passes, ball speed and initial surface roughness of the hole, whereas the responses are surface roughness, residual stresses and microhardness variation of the ballized hole. The optimal setting of the parameters is determined through experimental planning, conducted and analyzed using Taguchi method. It is found that the initial surface roughness of the hole exerted the greatest effect on surface roughness of the ballized hole, followed by interference and wall thickness of the hole. The No. of passes and ball speed were found to have only a slight influence on the surface finish. A critical interference (300 µm) exists for maximum improvement in roughness. Based on the experimental results, the optimal ballizing for compressive residual stresses were obtained at 4 mm wall thickness, 400 µm interference and 2 mm/sec ball speed.The initial surface roughness and No. of passes were found to have no significant effect on the residual stresses. The optimum conditions for surface roughness and residual stresses are different. The microhardness just below the ballized surface was improved up to 65%. The maximum depth of the plastically deformed layer was observed at 300 µm below the ballized surface. Generally, it was observed that the maximum value of the strain hardening increases with the increase in both interference and wall thickness. The results of confirmation experiment agree will with the predicted optimal settings.
finite cylinders placed on a ground wall is presented. The effects of free-end shape reading flat, hemisphere and cone top of the circular cylinder are examined. The numerical results were obtained using the computational fluid dynamic (CFD) code, Fluent 6.3.26. The three-dimensional unsteady flow filed is investigated using unsteady Reynolds averaged Navier-Stokes (URANS) equation along with the four equations v2-f turbulence model. This turbulence model is implemented in the CFD code using User Defined Function (UDF) and User Defined Scalars (UDS). The measurements of surface pressure distribution around the bodies are presented. The cylinder has an aspect ratio of 1.33 (h/D = 1.33) and faces flow with Reynolds number of 1.7 x 105 based on free stream velocity and cylinder diameter. The results show that the top free surface of the models affects the flow field, such as the development of the wake structure, recirculation zone and the reattachment zone. The results indicate also that the hemispherical free end cylinder is subjected to the larger flow induced vibration while the cone free end is subjected to the lowest flow induced vibration
Study on the parameters affecting the performance of adsorption cooling system /
قطاع الدراسات الهندسية / الهندسه الميكانيكيه
تخصص البحث : الهندسه الميكانيكيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 11
علي رحيم السيد الغلبان( aaghalban@yahoo.com - 01069915417 )
Silica gel; Adsorber; COMSOL Multiphysics®; Porous medium; Cooling system
This paper presents numerical simulation of a silica gel/water adsorption refrigeration system. The commercial COMSOL Multiphasics® code is used for simulation which employs the finite element multi-dimensional model for heat and mass transfer processes. The simulation has been carried out for rectangular tube adsorber. The proposed model is validated against available experimental data in the literature. The effects of cycle time, heating temperature, cooling temperature, contact coefficient of heat transfer between grains and heat exchange’s surface, evaporator temperature, grain size and adsorbing/desorbing bed layer thickness on the system performance were investigated. The results show that both3-D and 2-D modeling for section of the bed lead to predicting the performance of the entire bed with a good accuracy. One of the main results of this study is that the layer thickness which gives optimal coefficient of performance (COP) doesn’t depend on grain size. Moreover the results show that both of COP and specific cooling power (SCP) increase by decreasing grain size.
NUMERICAL STUDY OF ENHANCING HEAT TRANSFER USING TWISTED TAPE INSERTS /
قطاع الدراسات الهندسية / الهندسه الميكانيكيه
تخصص البحث : الهندسه الميكانيكيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 15
Y.A.F. El-Samadony
Heat transfer; Twisted tapes; Pitch ratio.
In the present work, a numerical study of heat transfer for flow inside tube using twisted tapes inserts is presented. Four models have been studied which are plain tube, tube with single twisted tape, tube with double twisted tapes co-swirling flow and tube with double twisted tapes counter swirling flow. The effect of twisted tape pitch and width ratio on heat transfer, Nusselt number, pressure DROP and effectiveness are studied. It is found that Nusselt number, effectiveness and pressure DROP are increased as pitch ratio decreased. Also, the results show that counter swirling tape inserts has Nusselt number higher than co-swirling tapes, single tapes, and plain tube by about 5-9 %, 14-22 %, and 55-80 % respectively. The results indicate also that twisted tapes with clearance ratio are less effective compared to the types of zero clearance (tight fit tapes). Finally, a good agreement has been found between the present numerical results and published experimental results.
ASSESSING THE ROLE OF POINT SAMPLE NEIGHBORHOODS /
قطاع الدراسات الهندسية / الهندسه الميدانيه
تخصص البحث : الهندسه الميدانيه
Engineering Research Journal \ / Vol. 36, No. 4 - October 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 7
رائد محمد كامل حسونة( rd3165@yahoo.com - 01061752756 )
Digital elevation modeling – point samples - neighborhood
In this study, mathematical models for the self and relative neighborhoods of spatial point configurations have been proposed. This was intended for data/check elevation point patterns. These models were based on some realized point patterns within an illustrative rectangular geographical window. This window includes the Nile Valley, Eastern Desert and South Sinai in Egypt. The investigated data and check patterns had point elevation values, which were based on the SRTM30 global elevation model. The trends of the neighborhood models agreed with those of the interpolation quality, as expressed in terms of the standard deviation of discrepancies. Moreover, closed expressions were proposed, which relate the terrain interpolation qualities with the relevant neighborhood models. It is recommended to use such criterion for planning the spatial distributions of elevation point patterns in digital terrain modeling.
In the current study, the global geopotential harmonic models are used to densify gravity values along precise leveling routes, and hence to minimize the discretization error in computing the orthometric correction and to represent an economical alternative. Furthermore, these models are checked regarding their capability of being the only source of gravity information along spirit leveling lines. The orthometric corrections, computed for two simulated test links, are compared with those resulting from using purely observed gravity. Based on the obtained results, it is recommended to use the geopotential harmonic models as an economical source of gravity information along precise levelling routes. Moreover, it is recommended to investigate the application of the remove-restore technique of geopotential models in the computation of orthometric correction.
The rise in the prices of raw material leads to the search for cheaper and lighter a raw material which reflects on the total cost of the construction project .The aim of this study was to reduce the bulk weight of concrete through partial replacement of the coarse aggregates with variable percentages of light weight aggregates (Pumice). In addition to that further investigation on reducing the bulk weight through development of hollow core in concrete cubes with variable diameters. Silica fume was added to concrete mix in order to enhance the performance of the concrete mix. Use of silica fume with 450Kg/m3 cement achieved positive results in this study even with the existence of a Hollow core in concrete.
جميع البيانات التي يتم تسجيلها على النظام هي ملك للجهة صاحبة هذه البيانات
لا يتم الاطلاع على هذه البيانات من قبل مهندسي المركز إلا للضرورة القصوى ولغرض الدعم الفني وبالاتفاق مع الجهة صاحبة البيانات شفوياً أو كتابياً
لا يتم إعطاء أي بيان من بيانات النظام لأي فرد او جهة فرعية تنتمي للجهة صاحبة البيانات او لأي جهة أخرى إلا بموافقة كتابية من الجهة صاحبة البيانات
يمكن استخدام البيانات المسجلة على النظام بهدف عمل إحصائيات يستفاد منها فى قياس اداء النظام وكفاءة استخدامه من قبل مستخدميه
يتم تأمين جميع البيانات الخاصة بالنظام من خلال تأمين الحاسب الخادم الذي يستضيف البيانات ومن خلال تأمين انتقال البيانات بين جهاز المستخدم والحاسب الخادم وكذلك تأمين واجهة النظام التي يستخدمها المستخدم
كل مستخدم للنظام مسئول مسئولية كاملة عن كلمة المرور الخاصة به وعليه اتخاذ كافة الاحتياطات الممكنة حتى لا يستطيع أى شخص آخر الحصول عليها
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