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International Review on Modelling and Simulations Vol. 4 N. 4---- Part A
International Review on Modelling and Simulations Vol. 4 N. 4---- Part B
International Review on Modelling and Simulations Vol. 4 N. 4---- Part C
International Review on Modelling and Simulations (Vol.
4 N. 4) - August 2011 - Papers (Part A)
International Review on Modelling and Simulations (Vol.
4 N. 4) - August 2011 - Papers (Part B)
International Review on Modelling and Simulations (Vol.
4 N. 4) - August 2011 - Papers (Part C)
International Review on Modelling and Simulations - Papers (Part A)
Multicell
Converters Hybrid Sliding Mode Control
by O. Benzineb, F.
Taibi, M.E.H. Benbouzid, M.S. Boucherit, M. Tadjine
Vol. 4. n. 4, pp. 1396-1403
Abstract - This
paper deals with hybrid sliding mode control of multicell power
converter. It takes into account the hybrid aspect of the conversion
structure which includes the converter continuous and discrete states.
The basic idea used in this paper is to consider the interconnected
systems that represent the hybrid model and to generate commutation
surfaces based on a Lyapunov function that satisfies asymptotic
stability. Simulations are carried-out on a two-cells converter to
assess the performances and the robustness of the synthesized
controller.
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Keywords: Multicell Converter, Hybrid System, Sliding Mode Control, Interconnected Systems, Robustness.
Modelling and Simulation of a Hybrid Cascaded Seven Level Inverter Control for
Enhancement of Power Quality in High Voltage DSTATCOM Applications
by Ganesh Prasad
Reddy, K. Ramesh Reddy
Vol. 4. n. 4, pp. 1404-1416
Abstract - Effort
for enhancement of power quality in distribution systems has been
increased gradually. Conventionally based, like fixed, mechanical
switched reactor/capacitor banks and static Var compensator has been
used for improving power quality issue in distribution power system.
This paper presents a study on modelling and simulation of a three-phase
Hybrid Cascaded Seven Level Inverter (HCSLI) is used in high voltage
Distribution Static Compensator (DSTATCOM) in Power System (PS)
application. Making use of the HCSLI has advantages of low harmonics
pollution, reduced number of semiconductor power switches and switching
stresses in comparison with a Conventional Cascaded Seven Level Inverter
(CCSLI). In order to enhance the power factor, compensate the reactive
power, regulate the capacitor DC voltage and eliminates the total
harmonics distortion (THD) drawn from Induction Furnace Load (IFL-JINDAL
STEEL) of HCSLI, Variable Switching Frequency Multicarrier Sub-Harmonics
Pulse Width Modulation (VSFMSHPWM) technique, Constant Switching
Frequency Multicarrier Sub-Harmonic Pulse Width Modulation (CSFMSHPWM)
technique, Fuzzy-Gain scheduling-Proportional-Integral Controller (FGPIC),
current references generator and current feed-forward loops are
developed. The VSFMSHPWM and CSFMSHPWM switching patterns are used as
control for the semiconductor power switches of HCSLI. The current
reference generator is used to derive the reference currents for
DSTATCOM and FGPIC is used for capacitors DC voltage regulation for
DSTATCOM. The proposed controller scheme is also to allow the operation
of HCSLI at various voltage ratings and constant/variable switching
frequency. The modeling and simulation of DSTATCOM with its proposed
controller topology is implemented in MatLab/Simulink software packages.
The simulation results are presented to show the effectiveness of the
proposed topology using VSFMSHPWM at various operating conditions in
comparison with a CSFMSHPWM.
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Keywords:
Power System, DSTATCOM, VSFMSHPWM, CSFMSHPWM, FGPIC, Current
Reference Generator.
A Ten-Level Inverter System for Dual- Fed Induction Motor Drive
by G.Sambasiva Rao,
Dr.K.Chandra Sekhar
Vol. 4. n. 4, pp. 1417-1425
Abstract - In this
paper, a ten-level inverter system for dual-fed induction motor drive is
described. The dual-fed structure is realized by opening the
neutral-point of the conventional squirrel cage induction motor. The
ten-level inversion is obtained by feeding the dual-fed induction motor
with an asymmetrical 4-level inverter from one end and a symmetrical
3-level inverter from other end. This inverter scheme does not
experience neutral point fluctuations and uses a lesser number of DC
sources compared to the series H-bridge topology. A multilevel carrier
based Sinusoidal Pulse Width Modulation is implemented for the proposed
drive where a progressive discrete DC bias depending upon the speed
range is given to the reference wave to reduce the inverter switchings.
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Keywords:
Carrier Based SPWM, Dual-Fed Induction Motor, Reference
Sinusoidal Signal, Ten-Level Inverter, Triangular Carrier Signal.
Mathematical Model of a Three-Phase Diode Rectifier Feeding a Controlled Buck
Converter
by T. Sopapirm,
K-N. Areerak, K-L. Areerak
Vol. 4. n. 4, pp. 1426-1438
Abstract - Dynamic
models of power converters are normally time-varying because of their
switching actions. Averaging methods are widely used to eliminate the
switching behavior to achieve the time-invariant models. This paper
presents how to derive the mathematical model of a three-phase diode
rectifier feeding both uncontrolled and controlled buck converters. The
DQ modeling method is used to analyze the dynamic model of a three-phase
rectifier including the transmission line on AC side, while the
generalized state-space averaging (GSSA) modeling method is applied to
derive the dynamic model of a buck converter. Intensive time-domain
simulations via the well-known software packages with the exact topology
models are used to validate the proposed models. The simulation results
show that the proposed mathematical models provide high accuracies in
both transient and steady-state responses. The reported models are
suitable for the system analysis and design.
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Keywords: Three-Phase Diode Rectifier; Controlled Buck Converter; DQ Modeling Method; Generalized State-Space Averaging Method; Modeling And Simulation.
Simulation and Design of a Bi-directional DC-DC Synchronous Converter by
Intelligent Optimization Techniques
by K. S. Rama Rao,
Choon-Keat Chew
Vol. 4. n. 4, pp. 1439-1448
Abstract - This
paper presents modeling and a comparative study of three intelligent
optimization techniques for optimal design and analysis of a
bi-directional dc-dc converter with synchronous rectification. Two
converter models for the forward and backup mode of operation are
analyzed and the simulation results are compared to those of the
expected ideal operation to confirm the validity of the models. A
constrained optimization of the converter efficiency in the forward mode
of operation is performed by using Genetic Algorithm (GA), Scatter
Search (SS) and Simulated Annealing (SA) techniques to derive the
optimal parameters. The design and analysis of the converter are carried
out by using software tools within the MATLAB/ SIMULINK environment for
GA, and for SA and SS techniques the codes are written in C language.
The optimal parameters of the converter derived by the three intelligent
techniques are compared.
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Keywords: DC-DC Converter; Modeling and Simulation; Genetic Algorithm; Scatter Search; Simulated Annealing; Nonlinear Programming; Optimization.
Advanced Control Design for VM and PCM Controlled Multimodule Power Converters
by A. Altowati, A.
Shamekh, K. Zenger
Vol. 4. n. 4, pp. 1449-1457
Abstract -
Paralleling of power converters has become increasingly important for
reasons of increasing system reliability, facilitating system
maintenance, allowing for future expansion, and reducing system design
cost. However, paralleled DC-DC converters require a systematic modeling
methodology and a categorical current-sharing mechanism to improve a
performance of the overall system. To achieve desirable characteristics
when operating converter modules in parallel, the application of
quantitative feedback theory (QFT) to design robust controllers for a
DC-DC buck converter operating in continuous (CCM) is presented in this
paper. A systematic approach for modeling of parallel DC-DC converters
with current-sharing control is also proposed. The derived analytical
results are verified by simulations of a voltage-mode (VM) and a
peak-current (PCM) controlled buck converter.
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Keywords: Quantitative Feedback Theory, Multimodule Power Converter, Robust Performance, Voltage-Mode-Control, Peak-Current-Mode-Control.
Initial Guessing Generalized Formula for Selected Harmonic Elimination PWM
technique for Cascaded Multilevel Inverter
by Gamal M. Hashem,
Mohamed Darwish, A. Janbey
Vol. 4. n. 4, pp. 1458-1463
Abstract - This
paper proposes an accurate generalized initial guessing formula for
calculating the initial values of the switching angles for the Selected
Harmonic Elimination Pulse Width Modulation (SHEPWM) technique. This PWM
technique is suitable for high-voltage, high-power Multilevel Inverters
(MLI) used in fixed frequency applications. This PWM technique offers
more degrees of freedom for specifying the harmonics content in the
inverter output voltage, without any physical changes into the
traditional configuration of MLI. By using the proposed generalized
formula for switching angles initial guessing, the exact optimal
switching angles solution of the nonlinear set of system equations was
insured with minimum computational burden. Real-time implementation of
SHEPWM technique for controlling MLI output voltage could be easily
achieved. Different operating points for 5 levels inverter are
documented for three-phase system. Selected simulated results are
presented to verify and to validate the proposed approach.
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Keywords: Multilevel Inverters, SHEPWM, Programmed PWM, Harmonic Control.
Design and Simulation of new Soft Switching Coupled Inductor Half Bridge Current
fed Converter
by M.Delshad,
A.A.Derakhshan
Vol. 4. n. 4, pp. 1464-1469
Abstract - In this
paper a new zero voltage switching current-fed half bridge converter
with an active clamp circuit is proposed. The active clamp circuit not
only absorbs the voltage surge across the switches at turn off instance
due to leakage inductance, but also provides soft switching condition
for all the semiconductor devices. Implementation of control circuit is
very simple since the converter is PWM controlled and the auxiliary
switches turn on are complementary with respect to main switches. In the
proposed converter, two coupled inductor are applied in conventional
half bridge current fed converter for increasing converter gain. The
simulation results are presented to verify the converter operation.
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Keywords: Zero Voltage Switching (ZVS); DC-DC Converter; Pulse Width Modulation (PWM); Active Clamp.
Simulation of a Series Active Filter for Improvement of Power Quality
by M. SajediHir,
Y. Hoseinpoor, P. MosadeghArdabili, T. PeerzadeAshraf
Vol. 4. n. 4, pp. 1470-1473
Abstract - Power
quality issues have become an increasing concern due to an increase of
sensitive loads in distribution system. Users need constant sine wave
shape, constant frequency and symmetrical voltage with a constant root
mean square (rms) value and to satisfy these demands, the disturbances
must be eliminated from the system. The typical power quality
disturbances are voltage sags, voltage swells, interruptions, phase
shifts, harmonics and transients. There are various solutions to solve
power quality problems. One of the most effective solutions is the
installation of a Series Active Filter. Series Active Filter is able to
protect a sensitive load from the distortion in the supply side during
fault or overloaded in power system. The basic principle of a Series
Active Filter is simple, by inserting a voltage of required magnitude
and frequency, the Series Active Filter can restore the load side
voltage to the desired amplitude and waveform even when the source
voltage is unbalanced or distorted. The analysis and simulation results
validate the effectiveness of the Series Active Filter for mitigation of
voltage sag, swell and harmonic in distribution system.
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Keywords: Subsynchronous Resonances (SSR), Thyristor Controlled Series Capacitor (TCSC), NGH Scheme.
Hybrid Power Source with Battery/Supercapacitors for Uninterruptible Power
Supply (UPS)
by A. Lahyani, P.
Venet, A. Guermazi
Vol. 4. n. 4, pp. 1474-1482
Abstract - In this
paper, a power sharing system between the battery and the
supercapacitors in a 500 kVA rated uninterruptible power supply is
presented. Compared to typical batteries, the supercapacitors can be
charged and discharged very rapidly and can supply high current which
are important characteristics of an UPS. Supercapacitors are then added
as higher energy storage to overcome the full load power during short
time grid failures and to boost peak power during backup time of few
minutes. The high power demands applied to the battery are then smoothed
by the use of a low-pass filter. The potential reduction of the battery
stresses is subsequently studied. Mathematical models for battery and
supercapacitors pack are set up and validated through experimental and
manufacturer data. The UPS waveforms obtained by simulation with MATLAB/SIMULINK
are presented and analyzed.
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Keywords: Uninterruptible Power Supply (UPS), Supercapacitor, Lead Acid Battery, Stress Reduction.
Analysis and Simulation of a Shunt Active Filter for Improvement of Power
Quality and Power Factor
by M. SajediHir,
Y. Hoseinpoor, P. MosadeghArdabili, T. PeerzadeAshraf
Vol. 4. n. 4, pp. 1483-1486
Abstract - The use
of nonlinear loads and electronically switched devices in a wide range
has resulted in distorted current in the power system. Shunt active
filters can improve power quality in distribution system by injecting
reactive and harmonic currents. In this paper analysis and simulation of
an active shunt filter (ASF) for harmonic mitigation is discussed and
d-q-0 synchronous reference frame (SRF) is used to control the active
filter. The simulation is carried out using MATLAB/SIMULINK and the
simulation results illustrate the performance of shunt active filter in
mitigating the source current harmonics and improving the power factor.
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Keywords: Power Quality, Shunt Active Filter, Synchronous Reference Frame (SRF).
Harmonic and Reactive Power Compensations by Shunt Active Filter Controlled by
Adaptive Fuzzy Logic
by Salem Saidi,
Souad Chebbi, Houda Jouini
Vol. 4. n. 4, pp. 1487-1492
Abstract - The power
electronic developments and it’s integration in the electrical network
has generally negative consequences. Indeed, in the presence of
sinusoidal supply source and nonlinear load, static converters absorb
non-sinusoidal currents, and consume reactive power. To limit the
disturbances caused by these converters and to strengthen the system
dynamics, we propose in this present paper in one hand an intelligent
control of the DC link voltage and in the other hand the harmonic
current controls injected in electrical network via fuzzy logic
controller. In this context, we analyze two control types of the shunt
active power filter to be integrated on the studied system. These
control strategies are based on fuzzy logic and PI controller. Then, we
present a harmonic identification method witch rise from the principle
of the instantaneous active and reactive power calculating based on
fuzzy logic control. Many simulation tests are done and the obtained
results are very satisfactory.
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Keywords: Fuzzy Logic Control, Harmonic Currents, Reactive Power Compensation, Shunt Active Power Filter, Instantaneous Power (p–q) Theory.
Multisampled Digital Controller Simulation Model and Adaptive Design for DC-DC
Power Converters
by VaraPrasad
Arikatla, Jaber A. Abu Qahouq
Vol. 4. n. 4, pp. 1493-1499
Abstract - The
implementation of multi sampling digital control technique for power
converter applications has gainedattention due to the achievable higher
bandwidth and improvement of dynamic performance. This necessitates a
different compensator design based on the number of samples used. This
paper develops an adaptive model for closed-loop multi sampling digital
controller for DC-DC power converters. The developed model is able to
adaptively adapt and adjust its design for any number of samples
used.Simulation results using the developed model are presented and show
the ability of the adaptive model to adjust its design under number of
used samples variations while maintaining a stable closed-loop
performance.
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Keywords:
Modelling, Simulation, Power Converter, Dc-Dc, Digital Control,
Multi Sampling, Adaptive Control.
Predictive control of Brushless DC Motor Drive providing minimum Joule losses and torque ripple free commutation
by G. Gatto, I. Marongiu, S. Meo, A. Perfetto, A. Serpi
Vol. 4. n. 4, pp. 1500-1505
Abstract - A novel modulation technique suitable for the current control of brushless DC drives under commutation is presented in the paper. The pulse width of the chain voltages are determined by means of a predictive algorithm under the constraints of minimum Joule losses and torque ripple free commutation. At maximum speed the torque ripple appears but is lower than that of six step operation. The proposed technique leads also to higher mean torque than that of traditional six step operation. Simulation results highlight the better performance of the drive controlled by the propose algorithm with respect to that of the traditionally controlled drive.
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Keywords:
Brushless DC, Motor Drive, Predictive control, torque ripple free commutation.
Comparison Among Different Voltage Feeding Algorithms for Quasi-Resonant Dc Link Inverter-Fed I. M. Drives Based on State Feedback Approach
by G. Gatto, I. Marongiu, S. Meo, A. Perfetto
Vol. 4. n. 4, pp. 1506-1512
Abstract - In the paper two control techniques are compared respect to the traditional field oriented approach (F.O.), in order to define the range of applicability of each one. Targets of the different controls are to achieve a vector control and to generate firing commands for the quasi resonant inverter (QRI), that guarantee soft switching of the inverter switch, improving the dynamic response of the whole system. These targets will be obtained by means of a state feedback approach.
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Keywords: Quasi-Resonant Dc Link Inverter, Voltage Feeding Algorithms, I. M. Drives, field oriented control, State Feedback control.
A Series DC Motor Time-Varying System Control via a Stable Dynamic Inversion
Methodology using Adaptive Fuzzy Observer
by C. Maghzaoui,
H. Jerbi, M. N. Abdelkrim
Vol. 4. n. 4, pp. 1513-1521
Abstract - In this
paper we propose a time-varying observer for a series DC motor, based on
a stable dynamic inversion technique and a fuzzy logic system. This
algorithm is conducted to substitute the conventional control structure
of nonlinear system into a linear nonstationary one. This work deals
with two major concerns to control a DC motor. First, we start by
linearizing the nonlinear system along its nominal trajectory. We
construct after that the controller canonical form through a Lyapunov
coordinate transformation, which serves to compute, the control input
design. Second, we investigate the observer canonical form to design a
time-varying observer based on a fuzzy logic system. This advanced
structure will guarantee the convergence of the observer parameters and
the tracking error adjustment. The efficiency of the developed technique
is checked on a real speed trajectory tracking of a series DC motor.
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Keywords: Time-Varying Systems, Dynamic Inversion, Trajectory Linearization, Fuzzy Logic, DC Motor.
A Fractional Order Approach to the Modeling of Induction Machines
by Abdelhamid
Jalloul, Khaled Jelassi, Pierre Melchior, Jean-Claude Trigeassou
Vol. 4. n. 4, pp.
1522-1532
Abstract - This
paper presents a method for modeling three phase induction machines.
Park‘s transformation is used to obtain a system of differential
equations which allows to include the skin effect in the rotor bars of
asynchronous machines using an infinite dimensional ladder network. A
transfer function with a fractional derivative order has been used to
represent the admittance of the bar. A comparison between conventional
and fractional Park’s models exhibits the interest of fractional order
modeling of skin effect.
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Keywords: Induction Machines, Park’s Model, Skin Effect, Fractional Order Differentiation, Fractional Impedance, Ladder Network.
Discrimination among Internal Incipient Faults, Internal Faults and Inrush
Current of Transformer by using S-Transform
by A. Ashrafian,
M. Rostami, G.B.Gharehpetian, A. D. Falehi
Vol. 4. n. 4, pp. 1533-1541
Abstract - This
paper presents a novel method to discriminate internal incipient faults
from inrush current and internal fault currents of transformers based on
hyperbolic S-transform which is a very powerful tool for non-stationary
signal analysis in noisy conditions. The hyperbolic S-transform, of the
differential currents is computed. In this paper, the time-frequency
contours are obtained from S-transform. It is seen that the
time-frequency contours are different behaviors for internal incipient
faults, internal faults and inrush currents. A discrimination index is
proposed to distinguish between transformer transient currents. In order
to simulate the internal incipient, turn to turn and turn to earth
faults, the power transformer is modeled using 8×8 RL matrices obtained
from the subroutine BCTRAN of EMTP software and a model is used for
internal incipient winding faults. In order to compare the performance
of the S-transform and the wavelet transform, wavelet simulation has
been made, too. The algorithms are developed in MATLAB. The inputs of
these algorithms are differential currents derived from EMTP software.
The differential current signals are contaminated with noise and the
robustness of the wavelet transform and the S-transform based methods
under noisy environments is investigated.
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Keywords: Incipient Fault, Protection, Reliability, S-transform, Transformer.
Analytical Model of Radial Surface Permanent Magnet Synchronous Motor Dedicated
to Optimal Design
by S. Mendaci, M.
R. Mekideche, H. Allag
Vol. 4. n. 4, pp. 1542-1549
Abstract -
2D-analytical modeling approach for radial surface permanent magnet (PM)
synchronous motor is presented. Our developments are compared with 2D
finite elements proving a good accuracy. From the same model analytical
expressions of four constraint functions dedicated for an optimal design
of radial surface PM motor are developed. These constraints are:
electromagnetic torque, flux density saturation in stator/rotor core,
saturation in stator tooth and magnets demagnetization. It is found that
these analytical constraint functions are very simply and sufficiently
precise to be used in optimal multiobjective design problems.
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Keywords: Analytical Model, Demagnetization, Finite Element Method, Magnetic Field, Permanent Magnet Synchronous Motor.
Design of Magnetic Levitation System Controller Using Sliding Mode Control
by Tooraj Hakim
Elahi, Abdolamir Nekoubin
Vol. 4. n. 4, pp. 1550-1557
Abstract - The
objective of this paper were to determine by computer simulation and
laboratory test the dynamic characteristics of a Sliding mode controller
in magnetic levitation (Maglev) systems. In maglev trains, magnetic
suspension system is required to operate over large variations in air
gap. As a result, the nonlinearities inherent in most types of
suspensions have a significant impact on performance. Specifically, it
may be difficult to design a linear controller which gives satisfactory
performance, stability, and disturbance rejection over a wide range of
operating points. One way to solve this problem is through the use of
nonlinear control techniques such as Sliding mode control. In this paper
a sliding controller is proposed for controlling the two groups of
electromagnets embed in the module of the maglev train and the
superiority of nonlinear controllers over conventional controllers for
systems with large variations in operating point via simulations and
experiments on our system is demonstrated. Simulations and experiments
show that the controller can effectually control double-electromagnet
suspension system.
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Keywords: Magnetic Suspension System, Mathematical Model, Sliding Control.
Application of Stator Current Zero-Crossing Transitions for Sensor-less Vector
Control of Induction Motors
by Aliakbar
Mohammadi
Vol. 4. n. 4, pp. 1558-1562
Abstract - The paper
aims at illustrating a new method for sensor-less vector control of
induction motors. We use Zero Crossing Transition of stator currents to
estimate rotor speed. Zero crossing transition provides us useful
information which can be used for estimation of rotor speed and its
resistance. We extract useful information of zero crossing transitions
using Fast Fourier Transformation. Extracted information is used for
online estimation of rotor speed. To avoid time consuming Fast Fourier
Transformation (FFT), we use switchable high order Butterworth Filters
in order to extract rotor frequency. Simulation results express good
performance of this simple and inexpensive sensor-less vector control of
induction motors.
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Keywords: Zero Crossing Transition, Vector Control, Induction Motors, Speed Estimation.
Modeling and Simulation the Current Transformer for Measuring Current Harmonics
Using MATLAB-SIMULINK
by B. Vahidi, V.
Farahani
Vol. 4. n. 4, pp. 1563-1571
Abstract - The
present describe a method to teach power system engineers how to
represent the hysteresis in current transformer modeling. This algorithm
allows multi-valued hysteresis behavior to be represented. This method
has been implemented into MATLAB-SIMULINK to analyzed the current
transformer when excited with nonsinusoidal currents, a current
transformer is simulated and the results are shown. Evaluation of the
simulation with 40 students is very positive in terms of their
developing confidence in and understanding of this simulation.
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Keywords: MATLAB-SIMULINK, Current Transformer, Hysteresis.
Optimized Structure Design of Interior Permanent Magnet Motors for Electric
Vehicles Using a Method Based on FEM
by M. R. Besmi, S.
M. Rezvani
Vol. 4. n. 4, pp. 1572-1577
Abstract - Electric
motors play an important role in the success of Electric Vehicles (EV)
or Hybrid Electric Vehicles (HEV); so it is important to design an
optimized motor for The EV or HEV. Among the most important required
specification of EV's motors are high power density, high torque density
and high efficiency which involve maximum air gap flux density and
minimum Total Harmonic Distortion (THD) of flux distribution. Permanent
Magnets (PM) are buried inside rotor of Interior Permanent Magnet
Synchronous Motors (IPMSMs), thus IPMSMs have inherently high torque
density and efficiency due to the type of field and reluctance torque.
Different methods such as genetics algorithm are used in designing in
which Finite Element Method (FEM) is used only for design verification
because it is time-consuming. These methods have low accuracy because of
the simplifications that are made. That's why, this paper seeks to
introduce a FEM-based method which simulates different structures of IPM
and designs the optimal structure in terms of minimum THD, maximum air
gap flux density which is suitable for EV. Since this method hasn't been
simplified so much, it is more accurate than the current methods.
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Keywords: Design, Electric Vehicle, Finite Element Method, Interior Permanent Magnet Motor.
The New Pole Design for Interior Permanent Magnet Synchronous Machine
by Maryam
Zamanian,Mohammad Reza Besmi
Vol. 4. n. 4, pp. 1578-1582
Abstract - This
paper presented the better pole shape design for interior permanent
magnet synchronous machine (IPMSM). The new pole design was decreased
cogging torque under no load condition and value electric magnetic force
(EMF) in an air gap. Also, under a full load condition the torque ripple
was decreased noticeable. In the presented design, the difference
between d-axis inductance and q-axis inductance was reduced to the
minimum value. The presented new IPMSM is analyzed by using the
two-dimensional finite element method (2D-FEM).
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Keywords: Cogging Torque, Finite Element Method, Interior Permanent Magnet, Torque Ripple.
Design of Permanent Magnet Machine for Power Cooling Generation
by Houssem R.E.H
Bouchekara, Mohammed T. Simsim
Vol. 4. n. 4, pp. 1583-1590
Abstract - Magnetic
refrigeration is an innovative, revolutionary, efficient and
environmentally friendly cooling technology which is on the threshold of
commercialization. The essential components of magnetic refrigeration
systems are the magnetic field generator and the magnetocaloric
material. Based on the magnetic refrigeration technology, two structures
for use in permanent magnet machine for power cooling generation are
investigated and exposed in this paper. Both electromagnetic and thermal
studies are explored. The structures presented are composed of an outer
stator, a rotor and an inner stator. Each of the outer and inner stators
is fitted with Nm magnets. The rotor is composed of Nb blocks of
magnetocaloric material. In the first structure the number of magnets on
one stator is equal to the number of blocs (Nm=Nb). On the other hand,
in the second structure the number of magnets on one stator is equal to
the half of the number of blocs (Nm=Nb/2). The electromagnetic design
part has been accomplished by using the finite elements method and the
thermal design part has been achieved using a program developed under
Matlab.
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Keywords: Finite-Element Modeling, Magnetic Field, Magnetic Refrigeration, Permanent Magnets.
Performance Enhancement of Vector Controlled Drive with Neural Learning
Algorithm based MRAS Rotor Resistance Estimator
by M.Nandhini
Gayathri, S.Himavathi, R.Sankaran
Vol. 4. n. 4, pp. 1591-1597
Abstract - In recent
years, vector control schemes for induction motor drive systems have
gained wide acceptance in high performance applications. Vector Control
transforms the control of an induction motor to that of a separately
excited dc motor by creating independent channels for flux and torque
control. The success of the vector control scheme is the knowledge of
the instantaneous position of rotor flux. The position of the rotor flux
is measured in the direct vector control scheme and estimated in the
indirect vector control scheme. This requires a prior knowledge of the
machine parameters which makes the indirect vector control scheme
machine parameter dependent especially rotor resistance. MRAS based
rotor resistance estimation is simpler and easy to design. In this.
Paper, the vector controlled drive with Neural Learning Algorithm based
MRAS rotor resistance estimator is designed and validated through MATLAB/SIMULINK
simulation and compared with Conventional MRAS. The performance of the
vector controlled drive is analyzed extensively and the performance of
the estimator is also analyzed in terms of accuracy and settling time.
The promising results obtained are presented
.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Vector Controlled Drive, MRAS, Neural Learning Algorithm, Rotor Resistance Estimator.
Discrimination of Inter-Turn Stator Winding Fault from Phase-to-Phase Short
Circuit Fault in Permanent Magnet Synchronous Motor
by M. Taghipour ,
M. A. Shamsi Nejad, S. M. Razavi
Vol. 4. n. 4, pp. 1598-1609
Abstract -
Synchronous machines are one of the most useful equipments in electrical
industry. Permanent Magnet Synchronous Motor (PMSM) is a kind of
synchronous machines, which uses iron magnet for its rotor instead of
winding (wound field). Preventing electrical faults in electrical
derives is often impossible, therefore; designing effective fault
detection systems can help to improve its operation.
In this paper, minimum distance classifier has been introduced to
discriminate inter-turn stator winding fault from normal and
phase-to-phase short circuit fault condition. In addition, proposed
classifier has been used to detect faulty winding (damaged phase).
Discrete samples of magnitude of negative sequence component of
three-phase currents have been used for fault discrimination and
discrete samples of RMS value of three-phase current have been used for
damaged winding detection. Obtained results show that although proposed
method is one of the simplest classifier, it can discriminate inter-turn
fault from other conditions and detect damaged phase winding in less
than one duty cycle
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Inter-Tern Stator Winding Fault, Effective Pattern, Feature Extraction, Minimum Distance Classifier, RMAS Value Of Three-Phase Currents, Permanent Magnet Synchronous Motor (PMSM), Negative Sequence Component.
Modeling of Six-Phase Reluctance DC Machine Using Finite Element Method
by E.T. Rakgati,
T. Tsalaile, E. Gower
Vol. 4. n. 4, pp. 1610-1615
Abstract - In this
paper a per phase equivalent circuit model of the reluctance DC machine
is derived and investigated. The equivalent circuit parameters are
determined through finite element analysis for both no-load and load
conditions. The model is verified by comparing, amongst other things,
the torque calculated from the determined equivalent circuit with the
torque calculated by the finite element Maxwell stress tensor method and
the measured static torque of a 35 kW reluctance DC machine drive. It is
shown that the equivalent circuit parameters are severely affected by
the phase current commutation under full load and the armature reaction
effect.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: FE, Equivalent Circuit, Reluctance DC Machine, Armature Reaction, Maxwell Stress Tensor.
Direct Feedback Linearization Control of Grid Connected Synchronous Generator
by M. Hoseynpoor,
R. Ebrahimi, M. Davoodi
Vol. 4. n. 4, pp. 1616-1622
Abstract - This
paper proposes a new control structure based on the application of the
method of exact linearization by Direct Feedback Linearization for a
synchronous generator. The power system model consists of a single axis
flat rotor machine, connected to an infinite power bus. This way the
sub-transient phenomena are ignored. The global system consisting of a
turbine and a generator that produces the electrical output power is
coupled and it presents multiplicative and harmonic non-linearities. The
application of a DFL on the output voltage equation expressed as a
function of the electrical system parameters referred to the generator
practically turns the non linear system into two uncoupled subsystems
with the possibility of independently controlling the output voltage and
the frequency.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Power Systems Control, Control Non-Linearity, Linear Optimal Regulators, Linearization, Fault-Tolerant Systems.
Investigation of a Simple Control Scheme for Control of Induction Motors
by M. Hoseynpoor,
M. najafi, R. Ebrahimi, M. Davoodi
Vol. 4. n. 4, pp. 1623-1627
Abstract - Pulse
Width Modulation variable speed drives are increasingly applied in many
new industrial applications that require superior performance. The most
widely used PWM schemes for three-phase voltage source inverters are
carrier-based sinusoidal PWM and space vector PWM (SVPWM). There is an
increasing trend of using space vector PWM (SVPWM) because of their
easier digital realization and better dc bus utilization. This paper
focuses on SVPWM implemented on an Induction motor. The model of a
three-phase a voltage source inverter is discussed based on space vector
theory. Simulation results are obtained using MATLAB/Simulink
environment for effectiveness of the study.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Induction Motor Drive, Space Vector, PWM, Voltage Source Inverter.
Circuit Model of a Bar Conductor, Considering the Proximity and Skin Effects Via
non Uniform Mesh Approach
by M. R. Besmi
Vol. 4. n. 4, pp. 1628-1634
Abstract - In this
paper, a new approach for obtaining the circuit model of a bar conductor
with a rectangular cross section is presented. This approach is studied
for computing the inductance and resistance of current carrier
conductors with non uniform density, considering the proximity and skin
effects. For obtaining this model a non uniform mesh approach is
suggested, and the result of the analysis of the circuit with non
uniform mesh is inspected and compared with the state that uniform mesh
is used.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Circuit Model, Coil, Non uniform Current Density, Non uniform Mesh, Proximity and Skin Effects.
Design and Implementation of a Laboratory Scale Underground Cable Model
by M.Ali Anadol,
M. Aydin, T.Yalcinoz
Vol. 4. n. 4, pp. 1635-1641
Abstract - In the
recent years, an increasing trend towards researches dealing with
underground cable systems has been observed, which seem to provide an
alternative to classical overhead transmission lines. Most of the
studies conducted on this topic use simulation programs like
Electromagnetic Transients Programs (EMTP) to investigate the
characteristics of irregular wave distributions of the cable systems.
Laboratory applications with respect to load flow analysis such as basic
and harmonic frequencies or transient and steady state stability
generally require a physical underground cable model. In this study,
design of a physical underground cable model provided by a cascade
connection of lumped-parameter equivalent π (pi) circuits is presented.
The model is a laboratory scale simple design based on real cable data
and utilizes passive components. The cable model has been designed in
such a way that it could compatibly operate in the existing power
systems research laboratory of the university. The validity of the model
has been investigated through the experiments performed on a cable
model. The experimental results are compared with the results obtained
from the PSCAD/EMTDC simulation program.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Electromagnetic Transient Simulation, Transmission Lines, Underground Cable Model, PSCAD/EMTDC.
International Review on Modelling and Simulations - Papers (Part B)
Power Quality Improvement Using Parallel Operation of Power Electronic
Transformer
by M. R. Banaei, E. Salary
Vol. 4. n. 4, pp. 1642-1651
Abstract - Power
electronic transformer (PET) is a new type of transformer, which
realizes voltage transformation and power delivery in a power system
through power electronic conversion. The PET performs typical functions
and improvement of power quality in series state. In this paper,
parallel operation of PET as active power filter to compensate current
harmonics, unbalances and reactive power in power distribution systems
synchronous by series operation is discussed. In the other hands,
besides of feeding loads in series state, this transformer is able to
improve power quality when non linear loads are parallel with PET. Power
quality improvement with PET has been verified by the simulation results
using MATLAB/SIMULINK.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Power Electronic Transformer, Power Quality Improvement, Current Harmonics, Current Unbalances, Parallel Operation.
Charging Model of PHEV for Impact Assessment on Low Voltage Distribution
Networks
by Mario A. Rios,
Israel Roncancio
Vol. 4. n. 4, pp. 1652-1659
Abstract - It is
expected that electric vehicles market growth is coming ahead due to
ecological concern and energy efficiency maximization. As Plug-In Hybrid
Electric Vehicles are by now the up to date development in the electric
vehicles area and being aware of its plug to grid skills, it can be
inferred that the new loads these represent could affect current
electricity networks. This paper presents an alternative method to
determine this load based on a statistical approach using random
variables. At the end, a study case is portrayed to exemplify the above
mentioned approach, some conclusions are expounded and targets of
further work are set.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Distribution Network, Load Model, Plug-In Hybrid Electric Vehicle PHEV, Random Variable, Statistics.
Power System Stability Improvement using Comprehensive FACTS Devices
by M. Hoseynpoor,
M. Najafi, R. Ebrahimi, M. Davoodi
Vol. 4. n. 4, pp. 1660-1665
Abstract - Recent
studies reveal that FACTS controllers could be employed to enhance power
system stability in addition to their main function of power flow
control. The literature shows an increasing interest in this subject for
the last two decades, where the enhancement of system stability using
FACTS controllers has been extensively investigated. The low frequency
oscillations (LFO) usually occur in power systems due to disturbances
such as mechanical power variation. The power system stabilizers (PSS)
are usually applied to damp these disturbances. Flexible ac transmission
systems (FACTS) devices can be used to control power flow in
transmission lines. PSS can be replaced by FACTS if it is applied to
control the damping. In this paper, the linear model of power system
(single machine connected to infinite bus), possessing FACTS devices is
investigated. New controllers are designed and simulated for all four
FACTS devices inputs. PSS is also designed and simulated for the
investigated system assuming the absence of FACTS. The simulation
results well shows that these controllers damp the oscillations faster
and with better indices in compare with the PID and conventional
stabilizers.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Low Frequency Oscillations, Flexible ac Transmission Systems, Damping, Power System Stabilizer.
Fixed-Speed Wind Farm Operation Improvement by Using Current Source Converter
Based STATCOM
by Ali Ajami,
Mehdi Armaghan
Vol. 4. n. 4, pp. 1666-1673
Abstract – In this
paper, a STATCOM based on the current-source converter topology is used
for the flexible integration of pitch controlled fixed speed wind
generator (FSWG) to IEEE 13 node test feeder. It allows an optimized
reactive power injection during voltage dips occurred in the grid, and
helps the fixed speed wind generator to build its terminal voltage. The
nonlinear model of the current-source converter, which is the source of
the difficulties in the controller design, is modified to a linear
model. The modeling technique is not based on the linearization of a set
of nonlinear equations around an operating point. Instead, the power
balance equation and a nonlinear input transformation are used to derive
a linear model independent of the operating point. This model acts as
the basis for the design of a decoupled state-feedback controller. The
optimal control method linear quadratic regulator (LQR) is used to
determine the optimal state-feedback gain matrix. The pitch angle is
controlled in order to limit the generator output power to its nominal
value for high wind speeds. The results of simulation carried out by
using MATLAB/SIMULINK software show the performance of the proposed
STATCOM and prove the validity of the proposed topology.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: STATCOM, Wind Turbine Induction Generator, Current Source Converter, Decoupled State Feedback Control, LQR.
Probabilistic Approach for Wind Generation Placement Aiming at Congestion
Management
by H. Ahmadi, M.
Tasdighi, M. Ansari, M. Mosadeghi
Vol. 4. n. 4, pp. 1674-1682
Abstract - Due to
the increment in energy demands, congestion in transmission lines
becomes frequent. As a solution, forcing counter flows through these
lines will eliminate the need for new transmission line installation. In
this context, efficient wind farm (WF) placement method is proposed in
order to reduce burdens on congested lines. WFs with high level of
penetration are being established in power systems worldwide more
rapidly than other renewable resources. The Independent System Operator
(ISO), as a policy maker, should propose appropriate places for WF
installation in order to maximize the benefits for the investors. There
is also a possibility of congestion relief using the new installation of
WFs which should be taken into account by the ISO when proposing the
locations for WF installation. Since the wind speed is a random variable
and load forecasts also contains uncertainties, probabilistic approaches
instead of deterministic methods should be used for this type of study.
Aiming at this purpose, normal distribution is assumed for loads and
wind speed at peak demand according to forecasted data and vulnerable
lines to congestion with corresponding probability densities are
determined. AC probabilistic optimal power flow (P-OPF) is formulated
and solved using Monte Carlo Simulations (MCS). Besides, point estimate
methods (PEM) are used as efficient alternative for time-demanding MCS.
Sensitivity factors are employed to show that injection at which buses
would reduce the flow at concerned lines. N-1 contingency analysis is
also carried out using the sensitivity factors for ensuring system
reliable operation. The proposed methodology is tested on a 30-bus test
system.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Probabilistic Optimal Power Flow, Wind Power, Point Estimate Methods, Congestion Management.
Transient Stability Improvement with Fuzzy Control of STATCOM in Multi Machine
System
by Ali Marjanian,
Ehsan Jafari
Vol. 4. n. 4, pp. 1683-1689
Abstract - In this
paper, the goal is the improvement of transient condition in a
multi-machine system with designing of the non-linear controllers for
static Synchronous Compensator (STATCOM). First, in this paper, with
obtaining the Lyapunov Function of multi-machine system, in the presence
of STATCOM, close-loop controller(CLC) is designed so that causes the
enhancement of the critical clearing time of system, and damping out of
system in the transient conditions. Input signals of this CLC are the
variables of the measured system made by phasor measurement units (PMU).
But this controller cannot damp out the system transient oscillations
well. Finally, system damping can be increased by Fuzzy controller after
occurrence the fault. The results of the simulations confirm the Fuzzy
controller ability in the improvement of the system transient
conditions.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: STATCOM, Transient Stability, Close-Loop Controller, Fuzzy Control.
ImprovingTransient Stability Using CombinedGenerator Tripping and Braking
ResistorApproach
by Mostafa
Eidiani, Mohammad Ebrahimean Badokhty, Mahdi Ghamat, Hossein Zeynal
Vol. 4. n. 4, pp. 1690-1699
Abstract - In this
paper, improving in transient stability is sought through adevelopment
of combined approach. Since, in power systems, the maximum use of
existing capacities along with the increased powers transferred through
the transition lines make transient stability studies even more
important. When the fault occurs, the kinetic energy of system is
increased and if the system kinetic energy exceeds a certain amount,
system instability will meet. Generator tripping is also one of the most
effective methods of improving stability in case of severe faults. In
this method, we trip a number of units of a certain unit to stabilize
the system. In fact, siftingparticular set ofgenerators, it will
decrease the kinetic energy of the system so that stability can be
achieved. In generator tripping, for such reasons, the system has to
maintain stability where lest number of units can be possibly blown out.
Due to its thermal limitations, fixed place of resistor bank and
possibility of back swing, however the braking resistor is less
efficient than generator tripping. Inour proposed combined method,
system stability against severe turbulence is tackledwith minimum
tripping of generator units. At this proposal, the intensity of
faultwill be valuably lessen by applying braking resistor, and then, for
the purpose of improving transient stability, the kinetic energy is
reduced by removingcertain unit at the right time.The approach has been
tested on 9-bus with 3-generator system to demonstrate promising
effects.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Transient Stability, Generator Tripping, Braking Resistor, Energy Function.
Comparison of Imperialist Competitive Algorithm and Other Heuristic Methods for
Optimal Placement of UPFC in Electrical Power Systems
by Hadi Chahkandi
Nejad, Rouzbeh Jahani
Vol. 4. n. 4, pp. 1700-1708
Abstract - This
paper presents a Imperialist Competitive Algorithm to obtein the optimal
number and location of FACTS devices in a power system. Unified Power
Flow Controller (UPFC) has great flexibility that can control the active
and reactive power flow and bus voltages, simultaneously. Imperialist
Competitive Algorithm (ICA) is a new memetic meta heuristic algorithm
with efficient mathematical function and global search capability. The
objective is to maximize the transmission system loadability subject to
the transmission line capacity limits and specified bus voltage levels.
Using the proposed method, the location of UPFCs and their parameters
are optimized simultaneously. The proposed approach is examined and
tested on IEEE 14-bus system and IEEE 118-bus system. The results show
that the steady state performance of power system can be effectively
enhanced due to the optimal location and parameters of the UPFC.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Unified Power Flow Controller (UPFC); Maximize the Loadability of Transmission Lines; Imperialist Competitive Algorithm (ICA).
Optimal Operation of a Distribution Company in Restructured Power Systems with
Voltage Stability and Reliability Constraints
by Ahmad Heidari,
S.S.Mortazavi
Vol. 4. n. 4, pp. 1709-1716
Abstract - In a
restructured power system, a Disco’s aim is to minimize its costs and
simultaneously produce and deliver the power in a reliable and stable
situation. This Disco to provide these aims has lots of choices; one of
them for economic point of view is using renewable energy like wind and
one of them for reliable point of view is using system reserve and unit
reserves. This Disco also can purchase power from market based on
several contracts. For having more accuracy, AC power flow has been run
to give an opportunity to consider voltage stability and reactive power
issues. In this paper, an algorithm has been presented to include
characteristics of Disco for a day-ahead market. A case study with three
different kinds of interruptible load and using SVC has been run to test
usefulness of the proposed method.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: AC Power Flow, Benders Decomposition, Disco, Economic Dispatch, SVC, Reliability Constraints, Restructured Power Market, UC, Voltage Stability, Wind Energy.
Investigation of Recloser-Fuse Coordination in Distribution Systems Including
DGs
by M.S.Payam,
E.Bijami
Vol. 4. n. 4, pp. 1717-1722
Abstract - The Fuse-Recloser
protection schemes have been commonly used as an effective protection
schemes for the protection of distribution systems. Conventionally, the
protection schemes for the distribution systems have been designed prior
to implementation of Distributed Generations (DGs). Implementation of
DGs in a distribution system, causes the change in the value and
direction of short-circuit currents. Hence, the presence of DGs may lead
to miss-coordination of the Fuse-Recloser protection schemes. This paper
presents a new index for investigation of the inserted current due to
DGs in miss-coordination of Fuse-Recloser protection schemes. The
proposed method, introduces the effect of DGs on the protection systems
as a quantitative index. To show the efficiency of proposed approach, it
applies on the 33bus IEEE test system under various conditions.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Recloser-Fuse Coordination, Distribution Systems, Distributed Generation (DG)..
Power System Modeling for Instantaneous Voltage State Estimation
by J. Beiza, Mehdi
Salaynaderi, N. Taghizadegan, A. A. Dadjouyan, F. Kashefi
Vol. 4. n. 4, pp. 1723-1734
Abstract - This
paper is the first part of a work aimed at analyzing the power system
performance using instantaneous voltage estimation. The paper uses
traditional state estimation where redundant measurements are available.
The estimation is based on time domain state estimation and three
components of transmission network are considered for modeling in time
domain. The transmission line model, power transformer model and HVDC
link model are developed to estimate bus voltages in time domain. The
proposed approach is an efficient and accurate method for estimating
instantaneous voltage which has dynamic behavior of the power network.
The approach contributions are to assess power system performance and to
estimate power system quality indices. The test results are included to
illustrate the performance of the developed models.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Instantaneous Voltage, Time-Domain Modeling, State Estimation.
Voltage Stability Assessment Using Combined Neural Networks
by Saeid Niknafs,
Reza Ghadiri Anari
Vol. 4. n. 4, pp. 1735-1739
Abstract - This
paper deals with an assessment approach on power system voltage
stability using combined neural networks. A set of combined neural
networks are developed to estimate the voltage stability level at
different load conditions for the selected contingencies. The input
properties of the neural networks are generated from offline training
data with various simulated conditions using a conventional voltage
stability algorithm based on the L-index. The effectiveness of the
proposed method has been demonstrated through contingency ranking in
IEEE 30-bus system. The performance of the developed model is compared
with the unified single neural networks. Simulation results show that
the proposed method gives more accurate responses and has good
generalization abilities to be effectively used to determining local and
global stability margin for further improvement measures. Results can
also show clearly a desirable performance of the proposed system in
online prediction of the L-indexes of all the power system buses
simultaneously.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Power System Voltage Stability, Contingency Ranking, Combined Neural Network.
A Novel Logic Based Directional over Current and Under Voltage Relays for Three
Phase System
by G.Chandra
Sekhar, P.S.Subramanyam, B.V.Sanker Ram
Vol. 4. n. 4, pp. 1740-1745
Abstract - As a
prelude to study the protection scheme of Six Phase transmission line
the authors have developed Logic Based Directional Over Current and
Under Voltage relays for three phase system which can be extended to
protection of Six Phase System because Six Phase System can be
considered as two mutually coupled Three Phase Systems having mutual
coupling only for Zero Sequence components when Dual Three Phase
Transformation is used for analyzing the Six Phase System. A Novel
method for the development of a Logic Based Directional Over current and
Under Voltage Relaying Schemes has been presented for use in Three Phase
Systems using Matlab Simulink tool. The Highlight of the scheme is that
the present Current or Voltage wave forms are being compared with the
previous history of the corresponding wave forms of a few cycles
continuously so that when fault occurs the faulted current or voltage
wave form is compared with the corresponding previous healthy wave form.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Six Phase System, Logic Based Detection, Protection Of Three Phase System, Directional Over Current Relay, Under Voltage Relay.
Designing PID Controller for Wind Energy Conversion System using Simulated
Annealing (SA)
by M. T. Darabadi,
A. Danandeh, F. Hashemi, Y. Hashemi
Vol. 4. n. 4, pp. 1746-1750
Abstract - In this
paper, an optimal PID controller to control wind energy conversion
system is proposed. Wind model, in this paper, is nonlinear and the
generator is of double fed type. Coefficients of the proposed controller
are optimized based on simulated annealing (SA). In order to use this
algorithm, first this problem has to be formulated as an optimization
problem having objective function and constraints, and then to obtain
the most desirable controller, SA method should be utilized to solve the
problem. Simulation results are performed for wind variations in time
domain and have been shown to verify the effectiveness of the proposed
controller.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Wind Energy Conversion System, Designing Controller, Simulated Annealing (SA), And Double Fed Generator.
Lead-Acid Battery Behavior Modelling and Experimental Validation under a
Specific Climatic Condition for a Hybrid Solar-Wind System
by Ahmed Mohamed
Yahya, Adel Mellit, Abdel Kader Mahmoud, Issaha Youm
Vol. 4. n. 4, pp. 1751-1759
Abstract - In this
paper, behaviour modelling and experimental validation of a lead-acid
battery integrated in a hybrid solar-wind power generation (HSWPG)
system are presented and discussed. In order to determine the influence
of various parameters regarding the storage system operation, with a
particular focus on the temperature, for an optimal transfer of the
energy produced towards the loads, the mathematical model CIEMAT,
developed by the Spanish Research Centre for Energy, Environment and
Technology, has been used. The aim is to broaden the optimal management
of various energy conversions, from a point of view of physical and
chemical processes. Experimental data were collected from a system
installed at CRAER Nouakchott (Mauritania). The simulation results have
been compared to experimental measurements during both the charging and
discharging of the system, under the same operation and environmental
conditions. The results have lead to the battery working states in the
real hybrid solar–wind power generation system.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Lead–Acid Battery, HSWPG, Storage System, Modelling, Experimental Validation.
Design of Hybrid Active Power Filter to Improve Power Quality in Three-Phase
Electrical Distribution Systems
by N. Gupta, S. P.
Singh
Vol. 4. n. 4, pp. 1760-1772
Abstract - The
passive and active power filters have been proved their importance for
improving power quality by compensating reactive power and eliminating
harmonics caused by the non-linear loads. In this paper, a hybrid active
power filter is proposed and implemented by using a small-rated
three-phase active filter with a shunt connected passive filter
arrangement. Average power theory is used to generate the reference
current signal for active filter whereas passive compensation approach
is used for three most significant harmonics viz. 5th, 7th, and 11th.
The design procedure for determining the three-tuned filter’s parameters
is well presented. Triple-tuned filter simulated performance of
harmonics filtering is compared with three single-tuned passive filters.
Various simulations results are presented to study the performance of
proposed compensation approach using MATLAB/Simulink environment. The
salient advantages of the proposed topology of hybrid active filter are
reduced rating of voltage source inverter and power switching devices,
better filter performance, simplicity and practicability. The DC-link
voltage of active power filter is greatly reduced since the three major
frequencies will be compensated by three-tuned filter combination. The
simulation results verify the validity and effectiveness of the proposed
system.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Power Quality, Passive Filter, Active Filter, Hybrid Active Filter, Current Harmonic, Reactive Power Compensation, Single-Tuned Filter, Double-Tuned Filter, Triple-Tuned Filter, Average Power Theory, Total Harmonic Distortions.
The Effect of Distributed Generation in Distribution Network on Coordination of
Protective Devices
by Ali Reza
Fereidouni, Hamed Nafisi, Mehdi Garmrudi, and Hamed Hashemi Dezaki
Vol. 4. n. 4, pp. 1773-1780
Abstract - DGs are
being introduced to power systems to secure the electric power supply.
The increasing penetration of DG added to the distribution power system
creates new technical and economic challenges. It would be essential to
inquire into many issues involving these challenges. In connection with
physical integration, protection is one significant subject of those
challenges. In this paper, the interconnection of DG units with power
systems from protection point of view is discussed. The overcurrent
protection of radial line using fuses and autoreclosers before and after
merging a DG source is examined. Simulation is accomplished in PSCAD/EMTDC.
Since there is not any component in PSCAD/EMTDC to depict the fuse or
recloser, two models are designed for simulating the operation of both
fuse and recloser. These models can be utilized for any other
implementation. Simulations are carried out in detail to study the
effect of DG integration to the system from the prospective of
protection devices coordination. Also, the suitability of the classical
protection for the system after DG integration is examined. This study
demonstrates that coordination among fuses and reclosers in a
distribution system can be interrupted with substantial penetration of
DG. The impact of DG on protective device coordination is sensitive to
distribution system formation, DG place and size.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Distribution Network, Distributed Generation, Protection, Recloser and Fuse Coordination.
Automation System Software and Dispatching of Electricity Networks
by Saeid Nahi,
Somayeh Hajforoosh, Seyed M.H Nabavi
Vol. 4. n. 4, pp. 1781-1790
Abstract - The
purpose of Automation and dispatching systems in the national
electricity networks is monitoring, management, operation of electrical
networks and its components on the power plants, electricity
transmission lines and the posts. Other duties may be pointed out that
this system include: Monitoring on transmission, distribution and above
distribution networks, early recognition events and broadcast loads, so
that the network is in stable condition could be pointed. With
comprehensive information of various network parameters to the purposes
of development, management, supervision and implementation of preventive
maintenance and reduced costs in systems integration achieved with the
automation system. The software presented in this paper with different
parts of the network is connected therefore it is necessary to be
familiar with the hardware and equipment that include the electricity
distribution network, information necessary for dispatching, software
applications related to the hierarchy of power dispatching, SCADA
systems, modern RTU about posts and the two methods for automation
networks in the post and the advantages and disadvantages of each are
expressed. It is necessary to sample the electric grid, programs, the
results presented in this study is related to Iran that the real action
is in the running and operation of various parts, Structure, tasks,
strengths and weaknesses of this program has been expanded.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Modern Dispatching, SCADA System, Post Automation, Electricity Network.
A Novel Wind Farm Modeling to Improve Reliability Assessment of Power System
by Masoud Omidvar,
M.R. Haghifam, B. Somayeh Mousavi
Vol. 4. n. 4, pp. 1791-1798
Abstract - Renewable
energy offers a promising and exciting means of generating electrical
power. Wind energy is perhaps the most mature of the various renewable
energy technologies. A wind farm is a collection of wind turbines built
in an area to provide electricity. In this paper impact of wind farm in
power system reliability is investigated and a new procedure for
reliability assessment of power systems with wind farm in HLII level is
proposed. In proposed procedure, a wind farm is given as a generation
with probabilistic and stochastic generation. Historical wind velocities
in past years are used for extraction of probabilistic distribution
function for velocity and therefore for output electric power. Using
this function the output power of wind farm is divided into multi state.
Each state shows a certain output electric power with certain
probability for occurrence. The effect of wind farm on composite system
reliability is evaluated with consideration proposed model for wind
power and mathematical expectation concepts. As case study a portion of
Iran power system in south east of Iran is selected. As historical data,
wind velocity for twenty past years is gathered and used for modeling.
Finally acceptable results are obtained and achieved values in this real
network are reported.
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Keywords: Renewable Energy, Wind Farm, Reliability, Probability Modeling.
Congestion Management and ATC Enhancement with optimal location of FACTS devices
using Sensitivity indices
by J. Sridevi, J.
Amarnath, Dr. G. Govinda Rao
Vol. 4. n. 4, pp.
1799-1807
Abstract -
Available Transfer Capability (ATC) is an important index for
determining power delivery contracts and managing transmission
congestion. In power markets, large amount of uncertainties and dynamic,
continuous and time-varying features of power systems have great impacts
on ATC. Congestion management is one of the major tasks performed by
system operators to ensure the operation of transmission system within
operating limits. In the emerging electric power market, the congestion
management becomes extremely important and it can impose a barrier to
the electricity trading. This paper deals with the optimal choice and
allocation of FACTS devices for congestion management and ATC
enhancement using sensitivity indices. Two methods based on optimal
power flow are proposed to alleviate congestion in transmission lines
and tested. The first method reduces the reactive power losses under
normal and contingency conditions with multi type FACTS devices which is
tested on IEEE 24 rts system. The second method alleviates congestion in
transmission lines with optimal placement of TCSC and is tested on 30
bus system.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Available Transfer Capability, Congestion, Contingency, FACTS, Sensitivity.
Damping of Subsynchronous Oscillations Using Thyristor-Controlled Series
Capacitor
by M. SajediHir,
Y. Hoseinpoor, P. MosadeghArdabili, T. PeerzadeAshraf
Vol. 4. n. 4, pp. 1808-1811
Abstract - A
thyristor-controlled series capacitor (TCSC) substantially improves
transmission capacity and mitigates subsynchronous resonance (SSR). In
this paper damping of SSR using NGH scheme has been done. The IEEE first
benchmark model is adopted for studying SSR and its simulation. This
model has been used in most researches of SSR. Finally, using PSCAD
software, NGH scheme has been simulated. Simulation results show that
NGH scheme is effective in damping and works successfully.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Subsynchronous Resonances (SSR), Thyristor Controlled Series Capacitor (TCSC), NGH Scheme.
Modeling and Application of a D-STATCOM in Voltage Flicker Mitigation
by S. Sajedi, F.
Khalifeh, T. Karimi, Z. Khalifeh
Vol. 4. n. 4, pp. 1812-1816
Abstract - D-STATCOM
is one of the equipments for voltage flicker mitigation in power
systems. Voltage flicker, a phenomenon of annoying light intensity
fluctuation is caused by Electric Arc Furnace (EAF). The D-STATCOM is a
three phase and shunt connected power electronics based reactive power
compensation equipment, which generates and /or absorbs the reactive
power. A Distribution Static Synchronous Compensator (D-STATCOM) is used
to regulate voltage on a 25-kV distribution network. The (D-STATCOM)
protects distribution system from voltage flicker. Simulations are
carried out using MATLAB/SIMULINK to illustrate the use of (D-STATCOM)
in mitigating voltage flicker in a distribution system.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Power Quality, Energy Storage System (ESS), D-STATCOM, Voltage Flicker, Synchronous Reference Frame (SRF).
Investigation of Transmission Lines Voltage Regulation by Installing STATCOM
by S. Sajedi, F.
Khalifeh, T. Karimi, Z. Khalifeh
Vol. 4. n. 4, pp. 1817-1821
Abstract - The
Static synchronous compensator (STATCOM) is a shunt connected voltage
source converter (VSC) based FACTS controller employed for reactive
power control. SVC and STATCOM are members of FACTS family that are
connected in shunt with the system. This paper describes the independent
control of real and reactive power flow through a transmission line by
using the d-q (direct axis-quadrature axis) control strategy. In this
paper, principle of operation and the impact of (STATCOM) on midpoint
voltage regulation are analyzed. Finally, the performance of the STATCOM
is compared with static var compensator (SVC) under fault condition.
Simulations are carried out in Matlab/Simulink environment and
Simulation results show that STATCOM is effective in midpoint voltage
regulation on transmission line.
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Keywords: Flexible AC Transmission System (FACTS), SVC, STATCOM, Voltage Regulation.
Investigating the Potentials of Implementing a Demand Side Management (DSM)
Program for a Residential Consumption Control Plan in Hamedan - Iran
by M. H. Moradi,
M. Asadi, H. Faridi
Vol. 4. n. 4, pp. 1822-1828
Abstract - Major
parts of the peak loads in Iran are related to residential sectors.
Thus, implementing a consumption management program for residential
areas can decrease the peak load considerably. However, one method of
achieving this goal is to use smart load controllers but the consumer
satisfaction in residential sectors is also very important in
implementing this system. In order to achieve this goal, a load control
system was designed by considering Iran's social structure.
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Keywords: Demand Side Management, DSM, Load Control, Load Management.
A New Principal Component Analysis Methodology for Sensor Fault Detection and
Isolation
by Mohamed Guerfel,,
Sahbi Ghachem, Kamel Benothman, Mohamed Benrejeb
Vol. 4. n. 4, pp. 1829-1837
Abstract - This work
proposes a new methodology for sensor fault detection and localization
using principal component analysis (PCA). The PCA model is built to
maximize fault detection sensitivity using a new index. The localization
procedure is carried out using two methods. The first is based on the
variables contribution to the fault index. The second is based on the
reconstruction approach. The application is carried out on a three
interconnected tanks system.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Statistical Methods, PCA, System Monitoring, Sensor Fault, Detection, Localization, Reconstruction, Contribution Plots.
Analysis of Pollution Effect on Polymer Silicone Rubber Insulators
by Hassan Abniki,
Amir Asadi, Mohammad-Taghi Nabavi-Razavi
Vol. 4. n. 4, pp. 1838-1843
Abstract - Power
system performance not only depends on the quality of insulators, but
also insulator reliability too. Nowadays energy transfer is rising, so
the role of insulator will be more critical. This paper at first studies
the specifications of different types of insulators and after that,
characteristics of each type will be analyzed. Also, using a well known
model for polluted insulators, the effects of potential distribution and
electric field on silicone rubber insulator are investigated by COMSOL
multi physics analysis.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Polymer Silicone Rubber Insulator, Pollution, Potential Distribution, Electric Field.
Partial Discharge Simulation in Solid Insulation at AC Voltage on
MATLAB-SIMULINK for Educational Purposes
by B. Vahidi, S.
J. Hosseini
Vol. 4. n. 4, pp. 1844-1849
Abstract - Electric
discharges that do not completely bridge the electrodes are called
partial discharge. Although the magnitude of such discharges is usually
small, they cause progressive deterioration and may lead to ultimate
failure. It is therefore essential to detect their presence in a
nondestructive control test .This paper describes an efficient method of
teaching partial discharge of solid insulation, to undergraduate
students of power system groups in electrical engineering departments,
as a part of a high voltage course for senior undergraduate students.
The paper shows how to simulate the partial discharge in solid
insulation in order to teach students the basics of partial discharge,
and to practice analyzing the test results. In the first part of the
paper the theoretical aspect of simulation is described, and in the
second part the simulation method and results are described. Evaluation
of the simulation over several semesters with 80 students is very
positive in terms of their developing confidence in and understanding of
this simulation.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Partial Discharge, Insulation, MATLAB-SIMULINK, Simulation, Capacitance.
Simulation of Lightning Surge Propagation into Low Voltage Systems
by Hussain
Shareef, Azah Mohamed, K. Mohamed
Vol. 4. n. 4, pp. 1850-1856
Abstract - Power
system disturbances have been present since the inception of the
electric utility industry. However, yesterday’s loads are more forgiving
of disturbances than today’s modern equipment. The proliferation of
sensitive electronic equipments such as PCs, variable speed drives and
industrial programmable controllers has made us more aware of power
system disturbances, which went unnoticed in the past. In the normal
operation of power systems, unavoidable disturbances may happen due to
switching actions, faults and lightning overvoltage surges. Overvoltage
surges are damaging in nature and result in more frustrations and even
fire in rare cases. This research aims to investigate the impact of
overvoltage surges due to various types of lightning on a low voltage
system. It is done through simulation conducted under various scenarios.
Then based on the simulation results and parametric evaluation, the
impacts of different system parameters are finally summarized.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: ATP, Voltage Surge, Lightning, Overvoltage, Travelling Waves.
A Quadratic Model for Total Harmonic Distortion in a Dual- Tap Chopping
Stabilizer with Four-Quadrant Switches
by H. R.
Hafezinasab, H. Feshki Farahani
Vol. 4. n. 4, pp. 1857-1863
Abstract - One of
the most important devices in industry is AC/AC converter or AC chopper
which can be applicable in different fields. These choppers should be
designed and constructed in a way that output waveform looks like a
sinusoidal one and output voltage harmonics amplitude is minimized by
suitable switching. Different methods have been presented for AC
choppers among which PWM method can be mentioned. In this way, output
voltage varies between two upper and lower values and produced harmonics
are a function of PWM modulation index, upper and lower value of the
voltage as well. In this study, for a PWM AC chopper, the effect of
mentioned parameters on the THD has been investigated and a quadrant
polynomial relation has been obtained for THD versus these parameters
which can be used to evaluate AC choppers harmonic and THD. to verify
the obtained mathematical formulation, different simulations have been
done using PSpice and results have been studied and analyzed.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: AC chopper, PWM switching and Total Harmonic Distortion.
International Review on Modelling and Simulations - Papers (Part C)
Empirical Models for the Correlation of Global Solar Radiation under Malaysia
Environment
by H. A. Rahman,
K.M. Nor, M. Y. Hassan, M. S. Majidù
Vol. 4. n. 4, pp. 1864-1870
Abstract - This
paper proposes a new mathematical model to estimate module temperature
that has similar tropical climate such as Malaysia. The developed model
was based on measured hourly global solar radiation, ambient and module
temperature data of Malaysia (3.1°N and 101.7°E). Models were compared
using coefficient correlation (r), coefficient of determination (r2),
Mean Bias Error (MBE), Root Mean Square Error (RMSE) Mean Percentage
Error (MPE), t – statistic (t-Stat) and F – test. Results show that, the
proposed model gives the highest value of correlation coefficient r
(0.881), coefficient of determination r2 (0.776), and give good result
when considering statistical indicators i.e. low RMSE value (0.0382),
low MBE value (0.00698) , low MPE value (-0.00066). The t-statistic and
F-test were used as best indicators and more effective for determining
the model performance.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Ambient Temperature, Module Temperature, Empirical Model, Global Solar Radiation, Regression Analysis.
Multi-Objective Single Facility Location Problem: a Review
by Vaishali
Wadhwa, Deepak Garg
Vol. 4. n. 4, pp. 1871-1875
Abstract - Facility
location problems have been the problems gaining attention of various
researchers over the years. The problem is critical as it has found its
application in all sectors public and private. The decision needs to be
taken whenever a new facility needs to be located and where it should be
located in order to maximize the profit. Here facility may be any
resource that needs to be located in a predefined region e.g. any
college to be located in the city, opening a new retail outlet in a
metro city or locating a fire station. While locating various types of
facilities, different parameters need to be considered thus resulting
into several objective functions which needs to be optimized. The
objective function, determined by the resource to be located and
different involved constraints needs to be optimized for finding optimal
location of resource. Here, in this paper we have reviewed Single
Facility Location Problem and the various objective functions which
include minimizing the average sum of distances, minimizing the maximum
distance travelled and covering maximum demand of the customers.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Facility Location Problems, Minsum, Minmax and Maximal Covering Objective.
Free Vibration Functionally Graded Material Circular Cylindrical Shell with
Various Volume Fraction Laws under Symmetrical Boundary Conditions
by M.Setareh,
M.R.Isvandzibaei
Vol. 4. n. 4, pp. 1876-1882
Abstract - The
effects of the FGM configuration are studied by studying the frequencies
of two FGM cylindrical shells. Type I FGM cylindrical shell has Nickel
on its inner surface and stainless steel on its outer surface and Type
II FGM cylindrical shell has stainless steel on its inner surface and
nickel on its outer surface. The study is carried out based on third
order shear deformation shell theory. The objective is to study the
natural frequencies, the influence of constituent volume fractions and
the effects of configurations of the constituent materials on the
frequencies. The properties are graded in the thickness direction
according to the volume fraction power-law distribution. The governing
equations are obtained using energy functional with the Rayleigh-Ritz
method. The boundary conditions in this cylindrical shell made of two
material is free-free (F-F). Results are presented on the frequency
characteristics, the influence of the constituent various volume
fractions on the frequencies for a Type I, II FGM cylindrical shell.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Stainless Steel, Nickel, FGM. Free Boundary Condition.
On New Solutions for non-Newtonian Visco-Elastic Fluid in Pipe
by N. Moallemi, I.
Shafieenejad, H. Davari, A. Fata
Vol. 4. n. 4, pp. 1883-1888
Abstract - The
steady, laminar flow of a third grade fluid through a pipe is studied.
We propose and apply a homotopy perturbation method (HPM), to obtain
approximate analytical solutions for the velocity profiles. The effects
of the pressure gradient and the non-Newtonian parameter on the velocity
are discussed. Comparisons of the results show that homotopy
perturbation method is more effective and easy to use.
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Keywords: Homotopy Perturbation Method, Non-Newtonian Fluid, Third Grade Flow.
Integration of a Recent Profile Reduction Method in Finite Element Program for
Movement Simulation with Moving Band Method
by R. Saraoui, Y.
Boutora, N. Benamrouche, M. Ounnadi
Vol. 4. n. 4, pp. 1889-1895
Abstract - In this
paper, the performance of a recent profile reduction method which is
suitable for cylindrical structures is compared with well known
classical methods. It is found that the performance of this method is
better than Gibbs, Poole, Stockmeyer (GPS) method and Sloan’s method as
far as profile reduction is concerned. The renumbering time induced is
the lowest. Our contribution consists of adapting this method for taking
into account the movement by the moving band method and applied for
renumbering the mesh of a permanent magnet synchronous machine in its
electromagnetic modeling by finite element method (FEM) to compute the
torque. The renumbering is performed with the aim of minimizing the
profile of the stiffness matrix as well as the CPU time. Indeed, a
comparison with the remeshing method shows that it reduces strongly the
CPU time and it gives comparable results as far as accuracy is
concerned.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Finite Element Method, Moving Band Method, Permanent Magnet Synchronous Machine, Profile Reduction, Torque Calculation.
Thermal-hydraulic Modeling of a Radiant Steam Generator Using Relap5/Mod3.2 code
by A.L.Deghal
Cheridi, A.Chaker
Vol. 4. n. 4, pp. 1896-1899
Abstract - The
safety analysis of the thermal installations, based extensively on the
numeric simulation. The simulation analysis using realistic computer
codes like Relap5/Mod3.2 will help understand steam generator
thermal-hydraulic behavior during normal and abnormal conditions. In
this study, we are interested in the steady-state analysis of the high
power industrial steam generator using Relap5/Mod3.2 thermal-hydraulic
computer code. The industrial steam generator is a radiant type, natural
circulation, one drum and a combustion chamber in pressure. This steam
generator is designed to produce 374 tons/h of superheated steam at 73
bars and 487°C. The main results of this work are based on the
comparison between the steady-state results of simulation and the
measured operating data. The comparison shows that there is a good
agreement between the Relap5/Mod3.2 results and steam generator
operating data. The obtained results demonstrate the importance and
capability of the Relap5 code in the thermal-hydraulic analysis of steam
generator facilities.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Thermal-Hydraulic Simulation, Radiant Steam Generator, Relap5/Mod3.2, Steady-State.
Response to Customer Reliability Requirements with Reserve Market Management
by M. Najafi, M.
Simab, M. Hoseinpour, R. Ebrahimi
Vol. 4. n. 4, pp. 1900-1908
Abstract - An
algorithm for calculating required capacity in reserve market with
consideration of customer reliability request is presented in this
paper. In the first stage of the proposed algorithm, customer requested
risk level is considered as a constraint during reserve capacity
calculations and in the second stage, a model is rendered for clearing
in the reserve market. Duration that each unit is in service and its
response rate, affects reserve distribution among generation units and
risk level in load points. In addition to these technical items, it is
necessary to consider a probabilistic measure for risk level. One
important probabilistic measure of risk level for nominating generation
units in a reserve market is Expected Reserve Not Supplied Cost (ERNC)
which considers cost of Expected Reserve Not Supplied (ERNS). Concerning
these points, the ERNC in an optimization procedure is used during
calculation of required reserve capacity in this paper. The ERNSC has
been applied in the form of a flexible function. Also, attention is paid
to have a procedure of fair allocation of reserve cost and interrupted
load among customers.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Reserve Market; Cost Allocation; Reliability Requirements; Clearing Model; Expected Reserve Not Supplied Cost (ERNSC).
Lattice Boltzmann Simulation of Cavity Flows at Various Reynolds Numbers
by M.A. Mussa, S.
Abdullah, C.S. Nor Azwadi, R. Zulkifli
Vol. 4. n. 4, pp. 1909-1919
Abstract - The
lattice Boltzmann method (LBM) is a numerical method evolved from the
statistical approach that has been well-accepted as an alternative
numerical scheme for computational fluid dynamics (CFD). In comparison
to other numerical schemes, the lattice Boltzmann method (LBM) can be
regarded as a “bottom-up” approach that derives the Navier-Stokes
equation through statistical behavior of particle dynamics. Hence, this
paper presents the simulation of lid-driven cavity for deep and shallow
flow using the lattice Boltzmann method where the effect of the Reynolds
number on the flow pattern at aspect ratios of 0.25, 0.5, 1.5 and 4.0
was studied. These types of flow exhibit a number of interesting
physical features but are scarcely simulated using the LBM scheme. The
source code was established based on the BGK model on rectangular
lattice geometry. The comparison of the results was in excellent
agreement with those gathered from the literature even with relatively
coarse grids applied to the numerical calculation.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Lattice Boltzmann Method, Distribution Function, Microscopic Velocity, Lid-Driven Cavity Flow, BGK Model.
Vol. 4. n. 4, pp. 1920-1928
Abstract - The
effects of the FGM configuration are studied by studying the frequencies
of two FGM cylindrical shells. Type I FGM cylindrical shell has Nickel
on its inner surface and stainless steel on its outer surface and Type
II FGM cylindrical shell has stainless steel on its inner surface and
nickel on its outer surface. The study is carried out based on third
order shear deformation shell theory. The objective is to study the
natural frequencies, the influence of constituent volume fractions and
the effects of configurations of the constituent materials on the
frequencies. The properties are graded in the thickness direction
according to the volume fraction power-law distribution. The governing
equations are obtained using energy functional with the Hamilton's
principle. The boundary conditions in this cylindrical shell made of two
material is simply support-simply support (SS-SS). Results are presented
on the frequency characteristics, the influence of the constituent
various volume fractions on the frequencies for a Type I, II FGM
cylindrical shell.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Simply Support, Free, Cylindrical shell, Hamilton’s Principle.
Vol. 4. n. 4, pp. 1929-1937
Abstract - In this
paper Type I FGM cylindrical shell has Nickel on its inner surface and
stainless steel on its outer surface and Type II FGM cylindrical shell
has stainless steel on its inner surface and nickel on its outer
surface. The study is carried out based on third order shear deformation
shell theory. The objective is to study the natural frequencies, the
influence of constituent volume fractions and the effects of
configurations of the constituent materials on the frequencies. The
properties are graded in the thickness direction according to the volume
fraction power-law distribution. The governing equations are obtained
using energy functional with the Hamilton's principle. The boundary
conditions in this cylindrical shell made of two material is Free-simply
support (F-SS). Results are presented on the frequency characteristics,
the influence of the constituent various volume fractions on the
frequencies for a Type I, II FGM cylindrical shell.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Simply Support, Free, Cylindrical shell, FGM.
Effect of the Inclined Vibratory Excitation on Heat Transfer in a Space Filled
with a Nanofluid
by S.Kadri,
R.Mehdaoui, M.Elmir
Vol. 4. n. 4, pp. 1938-1944
Abstract - The
objective of this work is to study the effect of the inclined vibratory
excitation on the behavior of Al2O3-water nanofluid of natural
convection flow in a cavity. The horizontal walls are isothermal,
maintained at cold (Tc) and hot (Th) temperatures. The vertical walls
are adiabatic. The basic equations describing the flow driven by natural
convection consist of mass conservation, momentum and energy. For the
physical parameters of Al2O3-water nanofluid, we use the Brinkman and
Wasp model. Transport equations are solved numerically by finite element
method. A numerical simulation of the problem was performed using the
software Comsol Multiphysics. Results are presented in the form of
streamlines, isotherms, maximum current functions and the flux ratio.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Nanofluid - Natural Convection - Excitation Vibratory - Rayleigh Number - Cavity.
Numerical Study of Heat and Mass Transfer in a Porous Membrane Used in Energy
Recovery Devices
by R. Sebaï,
R.Chouikh, K. Amara, A.Guizani
Vol. 4. n. 4, pp. 1945-1951
Abstract - The
present work investigates the heat and mass transfer mechanisms in a
cross-flow parallel plate membrane based enthalpy exchanger for heat and
moisture recovery from exhaust air streams. The three dimensional model
which accounts simultaneously for heat and mass transfer in the membrane
and the channels. The results are compared to the available data and the
agreement is satisfactory. The effect of operating parameters such
aspect ratios of the rectangular ducts, volume flow rates and the
temperature differences on the effectiveness are also investigated. The
simulation result are applied for different outdoor design conditions of
two cities in Tunisia characterised by different humid climate area to
check the suitability of this proposed system to such conditions.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Heat Transfer; Mass Transfer; Membranes; Cross-Flow; Air Conditioning Recovery.
Survey and Analysis of Maintenance System for Horseshoe-shaped Section Tunnel
by K. Mosayebi, M.
Koohi, M. Mohammadi Dehcheshmeh, S. Fathi, M. Ostadali Makhmalbaf
Vol. 4. n. 4, pp. 1952-1961
Abstract - There is
no simple analytic solution about tunnels with non-symmetry central
section like horseshoe-shaped sections and for situation survey of
Tangential Stress on Tunnel Portal compound. The approximate solutions
are able to catch the stresses by confined component. In these sections,
created Boundary Stresses on ceiling or tunnel partitions depend on
tunnel section- shape and horizontal and vertical ratio of site. For
utilizing created stress concept besides underground holes, it is
necessary to have criteria or set of rules, to be able to predict rock
mass response to sets of created stress (in this case Hook destruction
criterion was used). The aim of this paper is to show created Boundary
stresses on ceiling or tunnel partitions are depends on tunnel section-
shape and horizontal, vertical ratio of site. It can conclude from
satisfactory results using Hook destruction criterion is effective to
predict rock mass response to sets of created stress.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Tunnel, Horseshoe-Shaped, Hook Destruction, Trangential Stress, Rock Mass.
Dynamic Analysis of Two Novel Micro-Systems for Optical Attenuation and
Modulation
by M. M. S.
Fakhrabadi, B. Dadashzadeh, V. Norouzifard, M. Dadashzadeh
Vol. 4. n. 4, pp. 1962-1967
Abstract - This
paper deals with presentation and analysis of two novel micro structures
for optical coupling, attenuation and modulation. The dynamic analysis
and control of the micro systems using piezoelectric and electrostatic
actuators which are two widely applied actuation systems are presented
in detail. The basic idea of both structures is the light coupling
between two micro waveguides and its control using the mentioned
actuators.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Micro-System, Optical Coupling, Piezoelectric Actuation, Electrostatic Actuation.
Vibrational Analysis of Graphene Sheets Using Molecular Mechanics
by M. M. S.
Fakhrabadi, M. Dadashzadeh, V. Norouzirfard, B. Dadashzadeh
Vol. 4. n. 4, pp. 1968-1973
Abstract - This
paper deals with investigation of the vibrational properties of graphene
sheets using molecular mechanics. The results include the shape modes
and natural frequencies of the mentioned nanostructure with various
aspect ratios and in different boundary conditions. The results show
that with increasing aspect ratio, the natural frequencies decrease.
Furthermore, cantilever boundary condition from the smaller side of the
graphene sheet has the minimum frequency values, whereas the fully
clamped boundary condition has maximum ones.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Graphene Sheet, Vibrational Analysis, Molecular Mechanics.
A New Fuzzy Approach on Planning and Decision Making in Engineering and
Construction Industry
by
Parna Imannejad, Ali Karimpour
Vol. 4. n. 4, pp. 1974-1981
Abstract - In recent
years engineering and construction industry faces formidable challenges
in control project and optimization of management decision making. The
requirements and challenges of today's world have made managers to
explore new methods in dealing with solving management problems, methods
with high flexibility, which can adapt plans to real conditions can help
one to make a decision at right time.This paper proposes a new method to
obtain the optimal solution in construction environment with uncertainty
and dynamics. Since linear programming is the most natural mechanism for
formulating a vast array of problems with the modest effort, we use
linear programming to solve this problem and we are modeling
uncertainties, dynamic information and linguistic terms of expert with
fuzzy theory. So in this research the optimal solution of the problem
will be obtained by using dynamic fuzzy linear programming approach and
MATLAB computation.
Copyright © 2011 Praise Worthy Prize S.r.l. -
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Keywords: Fuzzy Modeling; Fuzzy Decision Making; Planning; Dynamic; Linguistic Data; Uncertainty Handling.
Vol. 4. n. 4, pp. 1982-1987
Abstract - In this
article, the strain effect of asymmetric coupled quantum wells on the
extinction ratio (ER) and insertion loss (IL) parameters in
electroabsorption optical modulators are numerically simulated using the
transfer matrix method (TMM). The electroabsorption coefficient is
calculated over a range of asymmetric coupled quantum wells strain from
compressive (CS) to tensile (TS). The extinction ratio and insertion
loss parameters are evaluated from calculated electroabsorption
coefficient for TE input light polarization. The results of the
simulation show that the tensile strain from 0.05 to 0.2 % strain in the
wide quantum well has a significant impact on the extinction ratio and
insertion loss as compared with compressive strain whereas the
compressive strain of the narrow quantum well from -0.5 to -0.7 % strain
has a more pronounced impact on the improvement of the extinction ratio
and insertion loss as compared with tensile strain.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Asymmetric Coupled Quantum Wells, Electroabsorption Optical Modulators, Strain, Insertion Loss.
Analysis and Circuit Model of Optical Injection-Locked Semiconductor Lasers
by
Kambiz Abedi and Mohammad Bagher Nasrollahnejad
Vol. 4. n. 4, pp. 1988-1991
Abstract - In this
paper, a new circuit model for optical injection-locked semiconductor
lasers is presented, based on rate equations of the photon density,
carrier density and light field phase. By using this circuit model,
frequency response of optical injection-locked semiconductor lasers is
obtained by HSPICE simulation and compared to numerical simulation
results. The analysis results indicate that resonance frequency and
bandwidth are increased as injection ratio and detuning frequency are
increased. The corresponding results are in good agreement with the
results of previous numerical simulations. This circuit model will be
useful for the circuit level simulation of single device or
optoelectronic integrated circuits including optical injection-locked
semiconductor lasers.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Optical Injection-Locked Lasers, Equivalent Circuit Model, Detuning Frequency, Frequency Response.
Operating Temperature Correlation with Ambient Factors of Building Integrated
Photovoltaic (BIPV) Grid-Connected (GC) System in Malaysia
by
Hedzlin Zainuddin, Sulaiman Shaari, Ahmad Maliki Omar, Shahril Irwan Sulaiman
Vol. 4. n. 4, pp. 1992-1998
Abstract - Many
previous studies have been conducted in developing module operating
temperature model. However none of them had been conducted in a building
integrated photovoltaic (BIPV) installation in Malaysia. This paper
presents a revised Ross model for module operating temperature in
building integrated photovoltaic (BIPV) system in Malaysia. The proposed
revised Ross model is later compared with the established nominal
operating cell temperature (NOCT) model to analyse the suitability and
accuracy of both models for BIPV installation in Malaysia. The
comparison is made based on time series basis of measured, revised and
NOCT module operating temperatures for three typical days. For modelling
validation of the revised Ross and NOCT models, a correlation graph of
the predicted module operating temperature with measured module
operating temperature for total number of 937observations is plotted.
Hence, this validation is determined through root mean square error (RMSE)
and Pearson correlation coefficient (R2) values. Through the revised
Ross model, a new Ross coefficient for BIPV system in Malaysia under the
category of ‘Sloped roof: not so well cooled’ of 0.0348 oCm2W-1 has been
obtained. Furthermore, the R2 of both revised Ross and NOCT models are
0.8615 and 0.8642 respectively, which means that both models are still
in good agreement with the actual measured values. However, since RMSE
of revised Ross model (4.36 oC) is lower than NOCT model (5.21 oC), this
means that revised Ross model is more accurate than NOCT model. In
conclusion, the revised Ross model is more accurate than NOCT model in
predicting the module operating temperature for BIPV system in Malaysia.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: PV Module Operating Temperature, Ross Revised Model & NOCT Model.
Comparison
of Potential Power Plants in Jordan Using Analytical Hierarchy Process
by
Adnan Mukattash, Ahmed Al-Ghandoor
Vol. 4. n. 4, pp. 1999-2004
Abstract - This
paper uses Analytical Hierarchy Process (AHP) methodology to perform a
comparison between the different electricity power production options in
Jordan. The systems considered in this paper, in addition to fossil-fuel
power plants, are solar, wind, hydro, and nuclear power plants. The
results obtained via cost-to-benefit ratio show that solar, wind, hydro,
and nuclear power plants are, in the present conditions Jordan is going
through, the best alternatives for electric power production, though
with a little emphasis on the nuclear one. Solar power plants are the
best option, while fossil-fuel power plants turn out to be the worst
choice now followed by nuclear electricity.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Nuclear, Power Plant, Analytical Hierarchy Process, Jordan.
Dielectric
Constant Computation Model for N-Phase Porous Materials
by L.
Bouledjnib, S. Sahli
Vol. 4. n. 4, pp. 2005-2011
Abstract -
Dielectric constant in N-Phase porous materials is computed using
elaborated simples models based on the usual mixing rules. The
transition from two-phase to N-phase is assisted by a new formula which
reorganizes inclusions volume fraction in the mixture. To assess the
validation of the proposed approach, fives experimental samples of
porous composites have been used from the literature. This proposed
approach is applicable on Bruggeman, Looyenga, Maxwell Garnett and
Lichtenecker mixing rules in order to compute the dielectric constant
value and define the shapes of inclusions. It’s found that Looyenga and
Bruggeman mixing rules presented a good prediction of dielectric
constant comparing with experiment data, where the relative error was
found to be less than approximately 6%. From the obtained results, the
elaborated approach can be considered as a useful model for treating
N-phase case via the same mixing rules based on two-phase. The proposed
approach may have the potential in analyzing other properties such as
electrical conductivity and thermal conductivity in porous materials.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Dielectric Constant, Mixing Rules, N-phase Material, Porosity.
Modeling and Control of a new LSRM for Shunting the Railways Channels
by E. M. Barhoumi,
B. Ben Salah
Vol. 4. n. 4, pp. 2012-2019
Abstract - The aim
of this paper is to model and control a Linear Switched Reluctance Motor
(LSRM) for positioning the pointers of the railway channels. This type
of actuator is characterized by a high nonlinear static force. In first
part of this work, special attention was made to establish the nonlinear
static force and flux characteristic by means of the Finite Element
Analysis (FEA) in order to model the proposed actuator. In second part,
a concept of a new approach, based on the use of neural network is
proposed in aim to control the actuator. The obtained simulation results
confirm the efficiency of the proposed design and the control approach.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Linear Switched Reluctance Motor (LSRM), Finite Element Method (FEM), Flux Characteristic, Force Characteristic, Modeling, Neural Network Controller.
Development of a Transmission Line Scale Model for Evaluating Electric and
Magnetic Fields
by Adolfo Escobar,
Guillermo Aponte
Vol. 4. n. 4, pp. 2020-2026
Abstract - Electric
and magnetic fields from electric power lines have been studied for a variety of
reasons. Some of these investigations have included health concerns; however,
this issue has not yet been concluded. A high-voltage transmission-line scale
model can be used as a design tool to determine both the electric and magnetic
field distribution around the line. Also, the scale model permits to evaluate
options that can be used to reduce field magnitudes in sensitive areas. A scale
model allows to evaluate the design or mitigation technique effectiveness, like
changes in phase arrangement and current variations, before their realization.
In this paper, the development and construction of a 115-kV transmission-line
scale model to evaluate the different mitigation techniques to reduce the
electric and magnetic field levels produced by transmission lines is presented.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Transmission Line, Mitigation Techniques, Power Frequency, Electric Field, Magnetic Field.
Design and Analysis of Polymer Electrooptic Modulator Using the Full Vectorial
Finite Element Method
by Kambiz Abedi,
Habib Vahidi
Vol. 4. n. 4, pp. 2027-2031
Abstract - In this
article, a polymer electrooptic modulator has been designed and analysed by
means of the full vectorial finite element method. For this purpose, frequency
dependencies of modulators important parameters such as microwave effective
index, microwave characteristic impedance, and microwave loss, are extracted.
Finally, an ultra wideband and low drive voltage polymer electrooptic modulator
is designed as compared with those of other authors.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Electrooptic Modulators, Finite Element Method, Integrated Optics, Optical Communication.
Artificial Neural Networks Based Approach for Parametric Optimization of CMOS
Operational Amplifiers
by A. Jafari
Vol. 4. n. 4, pp. 2032-2037
Abstract - In this
paper, a method for optimization and automated sizing of CMOS operational
amplifiers (Op-Amps) is presented. In this method, artificial neural networks (ANNs)
are employed in order to determine the device sizes that optimize the circuit
performances. Neural networks can learn and generalize from data allowing model
development even when component formulas are unavailable. The training data are
obtained by various simulations in the HSPICE design environment with TSMC 0.18
µm CMOS process parameters. Using this method, practical examples with different
circuit topologies are designed in 0.18 µm CMOS technology. Simulation results
confirm the efficiency of the proposed method for analog circuits sizing.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Computer-Aided Design, Multistage Operational Amplifiers, Neural Networks, Multilayer Perceptron, Parametric Optimization.
Calculation and Visualization of Electromagnetic Fields Using EMP3: the Coaxial Line Example
by Konstantinos B. Baltzis
Vol. 4. n. 4, pp. 2038-2046
Abstract - The EMP3 pulsed-power simulation package is freely distributed software for the calculation, visualization and analysis of time-dependent electromagnetic fields. EMP3 calculates the propagation of electromagnetic pulses in three-dimensional systems using the finite-element time-domain (FE-TD) method. In this paper, we analyze the electromagnetic field of an open-ended coaxial transmission line which is excited by an electromagnetic pulse. We explore the spatial and temporal characteristics of the generated field and yield interesting conclusions. Within this context, we also discuss the main features, characteristics and applications of EMP3 and point out the benefits of its use in science, engineering and education.
Copyright © 2011 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords: Coaxial Line, Computational Electromagnetics, EMP3, Finite-Element Time-Domain (FE-TD), Freeware, Microwaves.
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