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International Review on Modelling and Simulations  Vol. 4 N. 6---- Part A

International Review on Modelling and Simulations  Vol. 4 N. 6---- Part B

International Review on Modelling and Simulations  Vol. 4 N. 6---- Part C



go to top    International Review on Modelling and Simulations (Vol. 4 N. 6)  - December 2011 - Papers (Part A)




go to top    International Review on Modelling and Simulations (Vol. 4 N. 6)  - December 2011 - Papers (Part B)




go to top    International Review on Modelling and Simulations (Vol. 4 N. 6)  - December 2011 - Papers (Part C)









International Review on Modelling and Simulations - Papers (Part A)


go to top   Evaluation of Capacitance Requirements for Constant Voltage Operation of a Self-Excited Induction Generator in Stand Alone Mode
         by K. Subramanian, K. K. Ray

          Vol. 4. n. 6, pp. 2749-2755


Abstract - In this paper, the authors proposed a simple technique to inject capacitors to regulate the terminal voltage of Self-Excited Induction Generator (SEIG) operating as a stand-alone mode. It is well-established theory that a minimum leading VAr (reactive volt-ampere) requires to meet the excitation of an SEIG when operating as a stand-alone mode. A simple model is proposed to realize the theory. Analysis of the steady state model shows that, as the load lagging reactive power increases a leading VAr is required to inject over and above the minimum capacitance to regulate the load terminal voltage. A simple soft switch technique is adopted to inject the capacitor to provide the necessary leading VAr. Experimental results and Mat lab simulation results shows the validity of the proposed system. Analysis of the result also presented.
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Keywords: Self-Excited Induction Generator, Capacitorse, Steadystate Analysis, Simulation, Soft Switching.



go to top   A Case for the Establishment of Malaysian Standard for Biodegradable Insulation Oil in Malaysia Transformers
         by Abubakar A. Suleiman, Nor Asiah Muhamad

         Vol. 4. n. 6, pp. 2756-2763


Abstract - – The dielectric properties of insulation oil in power transformers are dependent on the chemical structure of the oil. Although mineral oil based insulation oil is the common liquid dielectric used in power transformers, environmental and safety issues are pressurizing many stakeholders from developed countries to consider alternative fluid as transformer fluids. Vegetable (natural ester) based insulation oil is a viable alternative that has been commercialized in some countries. This paper presents results from the study done to ascertain the feasibility of using commercially available biodegradable insulation oil (Envirotemp® FR3™) for Malaysia power transformers. It was found that the tested oil failed to meet some of the standard insulating property values as stipulated in the Malaysian Standard (MS 2322:2010) and this was because the MS 2322:2010 is the standard for “Fluid for electrotechnical application-Unused mineral insulating oils for transformers and switchgear” which cannot be applied to Vegetable based insulation oil. This can lead to a misleading conclusion on the characteristics of natural ester oil as a substitute to mineral oil in power transformers. It is therefore pertinent to have a Malaysian standard property values for vegetable oil (natural esters) guiding researcher, manufacturer and users of “vegetable oil (natural ester) filled transformer in Malaysia”.
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Keywords:  Mineral Oil, Biodegradable Oil, Insulation Oil, Malaysian Standard, Power Transformers.



go to top   Starting Dynamics of Smart Motor Controller-Fed Induction Motors with Parameter Variation
         by Nafeesa K, Saly George

         Vol. 4. n. 6, pp. 2764-2769


Abstract - Starting performance analysis of smart motor controller-fed three phase induction motor drives is presented in this paper. Identically rated machines with different motor parameters are used for the work and establish the concept of dependence of optimum firing angle on motor parameters. The angle at which the negative torque pulsation is zero with minimum acceleration time and other electrical characteristics having satisfactory values is taken as the optimum firing angle. Effect of variation of each motor parameter on the starting performance is also investigated. Results shows that a suitable parameter combination significantly improved the starting performance
of induction motors.

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Keywords:  Induction Motor Starting, Optimum Firing Angle, Parameter Dependence, Smart Motor Controller.



go to top   About a Possibility to Fuse Monitoring and Testing
         by Adrian Plesca, Monica Rotariu, Florin Daniel Irimia, Mihai Andrusca

         Vol. 4. n. 6, pp. 2770-2779


Abstract - It presents a new possibility concerning the monitoring of the electrical equipment and installation, by using the information from the radiation electromagnetic field. The results contain in this article is obtained with the help of the numerical simulation in the EMTP software. It compares the numerical results with testing characteristics, experimentally determined for a high breaking capacity fuse.
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Keywords: Electrical Fuse, Data Acquisition, Monitoring, Magnetic Field, Testing.



go to top   Dynamic Analysis of Unbalanced Magnetic Pull in Squirrel Cage Induction Motors by the Improved Winding Function Method
         by Sadegh Shamlou, Mojtaba Mirsalim

         Vol. 4. n. 6, pp. 2780-2787


Abstract - Any kind of electrical, mechanical and magnetic unbalances causes unbalanced magnetic pull in electric machines. This paper presents the impacts of all kinds of static, dynamic, and mixed eccentricities, rotor skew and loading effects on unbalanced magnetic pull in three-phase squirrel cage induction machines by means of improved winding function method. The method also considers the exact function of air gap eccentricity, slot effects, magnetic intensity variation in the air gap, and the exact mmf function over a slot pitch. The simulation results show the high capabilities of the improved winding function method in very fast (a few minutes in contrast to hours and days) and accurate analysis of electric machines compared to the finite element method.
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Keywords:  Eccentricity, Improved Winding Function Method, Unbalanced Magnetic Pull.



go to top   Effect of Phase Advancing in a Stand- Alone Switched Reluctance Generator
         by M.Asgar, E.Afjei, A.Siadatan

         Vol. 4. n. 6, pp. 2788-2794


Abstract - The switched reluctance motor is a singly excited, doubly salient machine which can be used in generation mode by selecting the proper firing angles of the phases. Due to its robustness, it has the potential and the ability to become one the generators to be used in harsh environment. This paper briefly discusses energy conversion by a switched reluctance generator (SRG) when two switch per phase converter circuit and discrete position sensors are employed. It is well known fact that, as the generator’s speed increases by a prime mover the shape of current waveform changes in such a way that limits the production of generating voltage. At high speeds, it is possible for the phase current never reaches the desired value to produce enough back-EMF for sufficient voltage generation, therefore, the output power falls off. In order to remedy this problem, the phase turn on angle is advanced in a way that the phase commutation begins sooner. Since one of the advantages of this type of generator is its variable speed then, the amount of advancing for the turn on angle should be accomplished automatically to obtain the desired output voltage according to the speed of the generator, meaning, as the generator speed increases so should the turn on angle and vice versa. In this respect, this paper introduces an electronic circuit in conjunction with time reshaping of the command pulses obtained from position sensors and the drive converter to achieve this task for a desired output voltage when a SRG feeding a resistive load. To evaluate the generator performance, two types of analysis, namely numerical technique and experimental studies have been utilized on a 6 by 4, 30 V, SRG. In the numerical analysis, due to highly non-linear nature of the motor, a three dimensional finite element analysis is employed to calculate some of motor parameters and then using these parameter current shape and magnitude is computed, whereas in the experimental study, a proto-type generator and its circuitries have been built and tested using two switch per phase converter. A linear analysis of the current waveform for the generator under different advancements of the turn on angle has been performed numerically and experimentally and the results are presented.
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Keywords:  SRG, Switched Reluctance Generator & Control, Phase Advancing and SRG.



go to top   Dynamic Performance of Wind Asynchronous Generators Using Different Types and Locations of Fault
         by R. Rabbani, A. F. Zobaa

         Vol. 4. n. 6, pp. 2795-2801


Abstract - The most important factors restricting further utilisation of wind resources are the fortuitousness of the natural resource and the particularity of the technology used in wind power generation. In this paper, the dynamic performance of wind farms with an asynchronous generator (i.e. squirrel cage generator), are analysed in the case of various faults and disturbances in the transmission system. The focus of this study is on wind farms that are connected with transmission lines to the strong power system. The impact of the integrated wind farms on the voltage, reactive power, power flow and frequency at the connection point during disturbances is simulated. Furthermore, the effect of dynamic characteristics of the wind turbines on the grid transient voltage and the power system frequency stability are investigated. Simulation results for short circuit current contribution for different types of faults and locations obtained through transient analysis using a squirrel cage generator model are presented. Obtained waveforms are analysed to explain these behaviors, such as peak values for voltage, frequency, reactive power and short circuit current during disturbances for single line to ground, double line to ground, line to line and three phase faults.
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Keywords:  Squirrel Cage Generator, Frequency Stability, Voltage Stability, Short Circuit Level.



go to top   Dynamic Performance of the Wind Synchronous Generators with Different Types of Excitation Systems
         by S.Khaleghi Kerahroudi, A. F. Zobaa

         Vol. 4. n. 6, pp. 2802-2810


Abstract - In recent years there has been an increasing trend towards the use of wind power generation, also the requirements for the connection of wind power plants (WPPs) to the electrical grid has also significantly changed according to system operator [1]. Wind power plants include very different technologies such as synchronous and asynchronous generators. This paper investigates dynamic performance of wind synchronous generator using various types of exciter such as AC, Static and Solid state exciter. In addition the impact of various types of excitation system on short circuit current and transient voltage and frequency stability are studied.
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Keywords: Synchronous Generator, Excitation Systems, Stability, Short Circuit Currents.



go to top   Comparison between a Conventional and an Intelligent Direct Torque Control Strategy
         by Hamid. Chaikhy, Mohamed. Khafallah, Abd Ellah. Saad Khalid Chikh And Mouna. Es-Saadi

         Vol. 4. n. 6, pp. 2811-2816


Abstract - this paper presents a contribution for detailed comparison between fuzzy direct torque control (FDTC) strategy of Induction Machine (IM) using FLC and fuzzy logic switchers (FLS), and the conventional DTC using the two PI and IP controller. The performances of those two control schemes are evaluated and compared by simulation in terms of speed, flux, torque, current ripples and transient responses.
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Keywords:  Direct Torque Control, PI-Controller, IP-Controller, Fuzzy Logic Controller, Switching Table, Fuzzy Logic Switcher Induction Machine.



go to top   A New Approach of Minimizing Torque Ripple for Brushless DC Motor Using Current Controlled Space Vector Modulation Based Control Scheme
           by V.Viswanathan, S.Jeevananthan

           Vol. 4. n. 6, pp. 2817-2825


Abstract - This paper describes a novel Current Controlled Space Vector Pulse Width Modulation (CCSVPWM) technique to minimize the torque ripples in BLDC motor. The current ripple, created due to the stator winding inductance and deviation of back emf, leads to generation of ripple in the torque and prevents the usage of BLDC motor in a precise servo drive system. This technique can also serve to reduce the torque ripple because of current commutation. The paper includes MATLAB/SIMULINK results of conventional, unipolar, bipolar current control algorithms (CCAs), varying input voltage method (VIVM) and a new CCSVPWM approach. The comparison of simulation results show that the current waveforms of the current controlled SVPWM are smoother and the output torque exhibits lower ripple contents. This control method improves the system performance with low torque ripple.
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Keywords:  BLDC Motor, Current Controlled SVPWM Technique, Torque Ripple.



go to top   Direct Torque Control of Induction Motor Drive Using a New Pattern of Four Switch Three Phase Inverter
         by Seyed Jafar Salehi

         Vol. 4. n. 6, pp. 2826-2833


Abstract - This paper presents a novel control method for four switch three phase inverter (FSTPI) and will implemented in the induction motor drive. Look-up table in the new method will changed for improvement of various condition of drive performance , so a suitable switching table has been derived which selects the inverter switching states to fulfil the torque and flux requirements. Moreover comparisons with direct torque control (DTC) of induction motor fed by conventional FSTPI confirm that the new topology can be alternative to the conventional topology for low power low cost induction motor drive. Matlab simulink is used for simulation results.
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Keywords:  Induction Motor Drive, Direct Torque Control, Four Switch Inverter, Low Torque Ripple.


go to top   Modeling, Simulation and Torque Ripple Reduction of Three Phase Two Layers 6/4 Hybrid Switched Reluctance Motor/Filed-Assisted Generator
         by A.Siadatan, V.Najmi, E.Afjei

         Vol. 4. n. 6, pp. 2834-2845


Abstract - In this paper, a modeling and simulation analysis of two layers 6/4 three phase Switched Reluctance (SR) Machine is carried out. This machine consists of two magnetically dependent stator and rotor layers, where each stator layer includes six salient poles with windings wrapped around them, while the rotor comprises of four salient poles with different arc lengths and no windings. There is a stationary reel, which has the field coils wrapped around it and is placed between the two-stator sets. The distinctive point of this machine is its ability to work in motor and generator modes, which leads to hybrid operation. The mathematical model is carried out to obtain the characteristics of this machine (motor and generator). The torque ripple reduction is done as well by a novel introduced method using Rotor Shifting Method (RST). Furthermore, machine operations as SR motor and generator is simulated by 3D Finite Element Method (FEM). Finally, the mathematical model and simulation results are compared.
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Keywords:  Switched Reluctance Motor, Switched Reluctance Generator, Finite Element Method, Curve Fitting, Rotor Shifting Method.



go to top   Study of Switching Frequency and Dead Time Effect by SVPWM Implementation in FPGA Controller
         by Davar Ghalledar, Mehdi Samiei Sarkhanlo, Akbar Danandeh

         Vol. 4. n. 6, pp. 2846-2850


Abstract - In this paper effect of dead time and switching frequency on high frequency harmonics has been investigated. The Space Vector PWM (SVPWM) technique is designed and implemented for control three-phase voltage source inverter by using a FPGA (Field Programmable Gate Array) controller. In the power electronic sub circuit a voltage inverter is built of different modules and A new kind OF FPGA controller EP1C12Q240C8 of ALTERA is used in the control sub circuit. The dead time is necessary to prevent the short circuit of the DC link in PWM voltage inverters. In this case, delay between the pulse and reverse pulse to be changed and the software has been created, so we can check influence this phenomenon on the level of harmonic.
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Keywords: Dead Time, FPGA Controller, SVPWM, Switching Frequency, Voltage Inverter .



go to top  A Comparison of High Performance Control Algorithms for Three-Phase Shunt Active Power Filters
           by W. Lenwari, M. Odavic

           Vol. 4. n. 6, pp. 2851-2857


Abstract - In this paper, a three-phase shunt active power filter (SAPF) is introduced for compensation of harmonic currents caused by non-linear loads in the distributed power system. A SAPF is a power electronic device which has been developed to improve power quality. The current control of shunt power filters is critical since poor control can reinforce existing harmonic problems. Various control strategies have been proposed by many researchers. In this paper, a comparison evaluation of the performance of three current control algorithms, proportional plus resonant (PR), predictive based controller and iterative learning based controller, is presented with an identical system specification. The design procedure and principle of these current control methods are also presented in details. Simulation results show the comparison of transient response, steady state control and performance in the presence of variation of supply impedance between these control techniques.
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Keywords:  Shunt Active Power Filters, Proportional plus Resonant Controller, Predictive controller, Iterative Learning Controller, Power Quality.



go to top  Optimal Fuzzy Logic Controller Design for Shunt Active Power Filters
           by P. Prasomsak, K-L. Areerak, K-N. Areerak

           Vol. 4. n. 6, pp. 2858-2870


Abstract - The optimal design of the fuzzy logic controller to control the compensating current of the shunt active power filter is presented in the paper. The artificial intelligence technique called the adaptive tabu search (ATS) algorithm is used to design this controller to minimize the %THD of the source current. The Mamdani max-min and the mean of maximum approaches are used for the fuzzy inference and the defuzzification method, respectively. In the paper, the aim of the optimal design using the ATS algorithm is to design the input and output membership functions for the fuzzy logic controller. Moreover, the performance improvement of the instantaneous power theory to identify the harmonic currents of the power system is presented in the paper. The fuzzy logic controller with and without the ATS design are considered for the comparison of the harmonic elimination performance. The simulation results show that the fuzzy logic controller designed by the ATS algorithm can provide the minimum %THD of the source currents after compensation. The %THD also follows the IEEE Std.519-1992. In addition, the optimal design of the fuzzy logic controller based on the ATS algorithm does not need the engineering experience.
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Keywords:  Adaptive Tabu Search, Fuzzy Logic Control, Shunt Active Power Filter, Instantaneous Power Theory.



go to top  Optimal Design of Shunt Active Power Filters Using a Particle Swarm Optimization
           by T. Narongrit, K-L. Areerak, K-N. Areerak

           Vol. 4. n. 6, pp. 2871-2878


Abstract - This paper presents the application of a particle swarm optimization algorithm to design the shunt active power filter controlled by hysteresis current control. The objective of searching is to minimize %THD of the source current. The results are compared with that designed from Ingram and Round approach. The simulation results confirm that the particle swarm optimization can provide the minimum %THD of the source current compared with the Ingram and Round method. The %THD also follows the IEEE std.519-1992.The design of the shunt active power filter based on the particle swarm optimization algorithm is flexible and can improve the performance of the filter.
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Keywords: Particle Swarm Optimization, Shunt Active Power Filter, Hysteresis Current Control.



go to top   High Voltage-Boosting Converter Using Coupled Inductor and Charge Pump with Active Voltage Clamping
         by K. I. Hwu, Y. T. Yau

         Vol. 4. n. 6, pp. 2879-2886


Abstract - A high voltage-boosting converter is proposed herein, which combines one coupled inductor and one charge pump. Under a low input voltage with a high input current, the proposed converter has high voltage conversion ratio, and possesses an active voltage clamping circuit which pumps some portion of the leakage inductance energy to the output so as to increase the efficiency at light load, thereby causing the efficiency at light load to be very high. Hence, it is very suitable for the burn-in test of the buck-type converter. In this paper, the basic operating principles of the proposed converter are provided, together with some experimental results to verify its feasibility and effectiveness.
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Keywords:  Active Voltage Clamping, Coupled Inductor, Charge Pump, Voltage-Boosting Converter, Voltage Conversion Ratio.



go to top   Special Designed Power Switching Function Generator as a Complementary Tool in Learning Power Electronics        

          by Rosnazri Ali, Ismail Daut, Soib Taib, Noor Shahida Jamoshid

          Vol. 4. n. 6, pp. 2887-2893

 Abstract - This paper presents a special designed power switching function generator that produces 4 types of waveforms; square-wave, sinusoidal PWM, quasi-sinewave or multilevel and high-frequency DC pulses with a total of 14 different distinctive characteristics. The generator is exceptionally a useful tool to complement the students and researchers in power electronics areas which supports in their learning and design process. The generator is capable of producing selected waveforms which can deliver a 30W maximum power into a particular load. It is highly useful in harmonics analysis of inverters, true RMS measurements, switching devices driving signals, high-frequency switching transformer designs and filtering components for selective harmonics elimination.
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Keywords: Power Switching Generator; Harmonics Analysis; Driver Signals; High-Frequency Switching Transformer Designs.



go to top   A New Approach to Eliminate Undesired Harmonics of a Single-Phase Square-Wave Inverter Using a Transformer
         by N. Ghardash Khani

         Vol. 4. n. 6, pp. 2894-2900


Abstract - This article proposes a new method to eliminate undesired harmonics in the output of a single-phase square-wave inverter. The method has some important advantages that outweigh square-wave inverters and similar types. Besides being easy to control and construct, it has a high efficiency due to its low-frequency switching pattern. It would also be very useful in high-power demands, and capable of driving huge motors used in heavy industries. In this paper, the Matlab/Simulink simulation results of the whole system by the proposed method are presented and compared with experimental results of a prototype to verify its advantages over existing methods.
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Keywords:  Square-Wave Inverter, Driver, MOSFET, Transformer, Gate Pulse, Total Harmonic Distortion, Uninterruptible Power Supplies, SPWM (Sinusoidal Pulse Width Modulation), SVPWM (Space Vector PWM), IGBT (Insulated Gate Bipolar Transistor).



go to top   Mitigation of Subsynchronous Resonance by Subsynchronous Current Injection with STATCOM
         by M. Janaki, R. Thirumalaivasan, Nagesh Prabhu

         Vol. 4. n. 6, pp. 2901-2908


Abstract - A suitable selection of hybrid compensation can improve the power transfer capability and voltage regulation of long transmission systems. In this paper, hybrid compensation is realized by a combination of fixed series capacitor and shunt active FACTS controller STATic Synchronous COMpensator (STATCOM). The objective is to investigate the subsynchronous resonance characteristics of the hybrid compensated power system and propose a simple method for the extraction of subsynchronous component of line current using filter. The extracted subsynchronous frequency component is injected by the STATCOM at PCC, prevents the flow of subsynchronous current through the generator, and increases the damping of the system at critical torsional frequencies. This novel technique is termed as Subsynchronous Current Injection. The design of Subsynchronous Current Injector is based on damping torque analysis and Genetic Algorithm. The study system is adapted from IEEE First Benchmark model. The results show the effectiveness of the proposed Subsynchronous Current Injector in damping SSR. The SSR characteristics are analyzed based on linear analysis methods and nonlinear transient simulation. Linear analysis includes, Damping torque and eigenvalue analysis, which uses D-Q model of the system. The results of linear analysis are verified by performing transient simulation with detailed nonlinear model of the system.
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Keywords:  Subsynchronous Resonance (SSR), Torsional Interaction (TI), Damping torque, Eigenvalue, FACTS, Voltage Source Converter (VSC), Static Synchronous Compensator (STATCOM), Genetic Algorithm (GA).



go to top   Islanding Detection Method for VSI Based Distributed Generation by Considering its Switching Frequency
         by Umashankar S., Kothari D. P., Vijayakumar D.

         Vol. 4. n. 6, pp. 2909-2918


Abstract - Distributed or dispersed generation (DG) is widely used all over the world in order to avoid the transmission and distribution (T&D) line losses, to improve power quality, and to improve the voltage profile of the system etc. Unintentional Islanding is one of the major issues with DG. Current practice is that almost all utilities require DG to be disconnected from the grid with a maximum delay of 2 seconds of unintentional islanding (IEEE 1547 – 2003 standard). Islanding Detection methods can be broadly classified as Active, Passive and Hybrid methods, each having its own merits and demerits. Active detection method is safe reliable but very costly. Passive methods are comparatively cheap but they have a very large Non Detection Zone (NDZ). Hybrid detection methods have prolonged detection time as they use both the active and passive methods. This paper proposes one of the finest solutions to one of the above problems, achieving zero NDZ with a Passive islanding detection technique, considering the switching frequency of an inverter in the DG system. This also satisfies the IEEE (2 seconds) standard. Islanding is a phenomenon, which occurs when a section of the utility system containing a Distributed Generation (DG) is isolated from the main utility voltage source, but the local generation continues to deliver power to the local loads. Unintentional islanding may pose safety hazards as well as equipment damage at both the customer and the utility sides. This paper presents the modelling and development of the Phase Jump Detection (PJD) based passive Anti-Islanding scheme for the grid connected photovoltaic (PV) inverter. A closed loop control system utilizing the vector control and the SVPWM technique for the PV inverter with PJD scheme has been simulated in MATLAB/Simulink environment. The model has also been tested for various grid conditions with varying switching loads. The clear description of the model has been given and the results are then presented.
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Keywords:  Distributed Generation (DG), Islanding Detection, Phase Jump Detection, SVPWM Inverter, Anti Islanding.



go to top   A New Power Factor Correction Approach for Cost and Energy Saving in Industrial Motor Drives
         by D.Prince Winston, M. Saravanan, S.Arockia Edwin Xavier

         Vol. 4. n. 6, pp. 2919-2925


Abstract - Nowadays, Energy and cost saving are very important factors for industries. In industries, nearly 75% of the total load comprises motors. Motors may be dc or ac motors. Due to low price, less maintenance, robustness, and reliability, ac induction motors are used in most of the industrial applications. Induction motors have power factor problem. This paper gives the clear understanding of power factor for the beginners of this field. This paper describes the different power factor correction methods used in industries and also provides a new power factor correction approach for cost and energy saving in industry. The proposed method is verified by simulation using MATLAB-SIMULINK for a three phase 5.4 Hp and 150Hp squirrel cage induction motors. The practical work is done for 5Hp three phase squirrel cage induction motor. The results for both simulation and practical are discussed in this paper.
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Keywords:  Power Factor Correction, Loss Reduction, APFC, SCBAPFC, Power Converters, Industrial Thumb Rule, Three Phase Induction Motor.


go to top   Modeling and Simulation of DSTATCOM using Space Vector Pulse Width Modulation for Load Variation
         by K.Murugesan, Ranganath Muthu

         Vol. 4. n. 6, pp. 2926-2935


Abstract - Power system generators supply the required active power and part of the reactive power. Insufficient reactive power in the power system affects the bus voltage and the sensitive loads connected to it. To keep the bus voltage as per the grid code requirement, required reactive power should be supplied and excessive reactive power should be absorbed. Capacitor banks and reactor banks were acting as source and sink of reactive power respectively. Self-controlled thyristor switched capacitors and thyristor controlled reactors were also doing the same with improved performance. This kind of compensation at the load side with improved transient and dynamic stabilities is achieved by Distributed Static Synchronous Compensator or DSTATCOM. This paper focuses on modeling of Voltage Source Converters (VSCs) based DSTATCOM and its voltage regulation performance for load variations. Cascaded vector controller with Sinusoidal PWM (SPWM) and Space Vector PWM (SVPWM) switching algorithms have been studied in the MATLAB-Simulink environment. It is found that the SVPWM switching algorithm has reduced commutation losses, lower harmonic content and better amplitude modulation index compared to the SPWM switching technique.
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Keywords:  Cascaded Vector Control, Sinusoidal PWM, Space Vector PWM, Voltage Source Converter, Voltage Regulation.



go to top   Artificial Neural Network Based Three Phase Shunt Active Filter for Line Harmonic Elimination
         by N.Senthilnathan, T.Manigandan

         Vol. 4. n. 6, pp. 2936-2943


Abstract - Power quality is the ability of the electrical utilities to provide electrical power without interruption. The growth in the use of non-linear loads has caused power quality problems like high current harmonics and low power factor. Several control algorithms, which are usually used to resolve harmonic problems and their limitations, are discussed. This paper presents a new and simple control strategy to determine reference compensation currents, under balanced and unbalanced source voltages which uses the Voltage Source Inverter (VSI) for harmonic filtering of a three phase shunt active filter. Recently Neural Network (NN) based Shunt Active Filter (SAF) gains attention and in this paper a new control algorithm for NN based SAF is proposed. A three-phase six-pulse converter with resistive load is considered as the non-linear load and the switching pulse generation is based on carrier-less hysteresis based current control.The design concept of the SAF using the proposed NN based control algorithm is verified through simulation and the results proved the effectiveness of the proposed algorithm in reducing the overall percentage of total harmonic distortion (THD) and improving the power factor for non linear loads.
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Keywords:  Artificial Neural Networks, Shunt Active Filter, Voltage Source Inverter, Power Quality, Total Harmonic Distortion.



go to top   A Refined Space Vector PWM Signal Generation for Ten-Level Inverter
         by G.Sambasiva Rao, K.Chandra Sekhar

         Vol. 4. n. 6, pp. 2944-2953


Abstract - A refined space vector modulation scheme for a ten-level inverter system for dual-fed induction motor drive, using only the instantaneous sampled reference signals is presented in this paper. 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 asymmetrical four-level inverter from one end and symmetrical three-level inverter from other end. The proposed space vector pulse width modulation technique does not require the sector information and look-up tables to select the appropriate switching vectors. The inverter leg switching times are directly obtained from the instantaneous sampled reference signal amplitudes and centers the switching times for the middle space vectors in a sampling time interval, as in the case of conventional space vector pulse width modulation.
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Keywords:  Dual-Fed Induction Motor, Middle Space Vectors, Sinusoidal Reference Signals, Space Vector PWM, Ten-Level Inverter.



go to top   Constant Pulse Width Switching Strategy for Matrix Converter
         by M.Senthil Kumaran, R.Siddharth, M.Stalin, A.Divakhar, Ranganath Muthu

         Vol. 4. n. 6, pp. 2954-2960


Abstract - This paper explores a new constant pulse width switching (CPWS) strategy for Matrix converter utilizing all valid switching vectors. The method distributes voltage vectors with respect to minimum computed error. The important features of the technique include superior over modulation performance, inherent mitigating effect of unbalance at the input and constant pulse width switching (CPWS) leading to lower switching stresses. In this paper, under distorted input voltage conditions, behavior of the Matrix converter controlled by CPWS is analyzed. This proposed PWM algorithm is verified by MATLAB Simulation and hardware experimentation on laboratory prototype.
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Keywords: Matrix Converter, Unbalanced Input, Over-Modulation Index, Error Compensation.



go to top   Simulation Model of A Hybrid Energy System
         by Ahmed R. Abul'Wafa, A.T.M. Taha

         Vol. 4. n. 6, pp. 2961-2966

Abstract - A hybrid energy system (HPS) simulation model is developed to maximize the renewable energy extraction at Farafra, an oasis in Egypt. In Farafra a microgrid composed of 2*1.6 MW+1*2MW+2*2.5MW diesel generating units (DG) is already installed and serve an electric demand consisting of 52365 KWh/day. The system may need to be upgraded. In the model, part of the load is recommended to be supplied as deferrable load. Also battery/convertor modules are added in the HPS so that when renewable power generation exceeds local demand, energy can be stored and used during times when renewable power is not available or the electrical load increases. The model is based on two types of renewable power generation: wind turbine generator and photovoltaic generator in conjunction with existing diesel generators supply sources. The HOMER software was used to select an optimum hybrid energy system sized according to the electric demand, the availability of renewable energy resources and to maximize the renewable energy to total energy ratio. The optimization process simulates every system configuration in the search space and the feasible ones are sorted by total net present cost (NPC). Sensitivity analysis shows that the most least cost and optimized hybrid system is combination of 231 Enercon (330 kW) WTG; 155 Surrette 4KS25P batteries; and a 283 kW Convertor requiring only 3916 hours annual operation of one of the 1.6 MW diesel generators and 2306 hours annual operation of the 2.0 MW diesel generator. The two 2.5 MW diesel generators are saved. The photovoltaic array was not chosen because its costs were not justified with this particular solar regime and diesel cost.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Optimization Design, HOMER, Wind/PV Energy Hybrid System.



go to top   Insulated-Gate Bipolar Transistor Controlled Reactor
         by Abdulkareem Mokif Obais, Jagadeesh Pasupuleti

         Vol. 4. n. 6, pp. 2967-2972


Abstract - In this paper a controlled reactor using insulated-gate bipolar transistor (IGBT) is presented. Controlled reactors are usually implemented by using thyristors since the mid-1970’s and they are usually referred to as thyristor-controlled reactors. A thyristor-controlled reactor (TCR) is simply two anti-parallel thyristors connected in series with a fixed inductor or reactor. In TCR, it is only required to specify the instants at which its thyristors must start conduction. Once a thyristor conducts, its current keeps on flowing as long as its magnitude is above holding limit and hence no trigger is required after starting of conduction. In addition, a thyristor will be naturally commutated as soon as its current decays below holding limit. For IGBT, the instant at which the device must start conduction and the conduction period must be both identified because maintaining conduction requires keeping on activating the device gate as long its current is still greater than zero. The problem is how long should the IGBT conduct and when it will be turned off? In this paper a reliable control strategy is adopted for presenting the IGBT as a good replacement of thyristor in controlled reactors. A demonstrating system is designed and implemented on the computer program PSpice.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Controlled Reactor, Power Quality, Reactive Power Control, Static VAR, TCR.



go to top   On the Sliding Mode Control of Saturated Systems Subjected to Norm Bounded Uncertainty
         by Borhen Torchani, Anis Sellami, Germain Garcia

         Vol. 4. n. 6, pp. 2973-2984


Abstract - This paper deals with robust control of saturated systems. It presents a design methodology of sliding mode control of a class of linear systems with the presence of both constraint of saturation and norm bounded uncertainty. In a first step, the design of the sliding surface is formulated as a problem of root clustering of reduced uncertain system, what leads to the development of a continuous and non-linear control law. In a second step, a robustness analysis is performed. As result, an approximation of the trajectory deviation of the uncertain system compared to the ideal behavior is proposed. Finally, a numerical application to double mass-spring-shock absorbers with one actuator is illustrated to validate the theoretical results of this work.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Sliding Mode Control, Norm Bounded Uncertainty, Saturation, Robustness.



go to top   An Accurate Multi-Train Simulation Tool for Energy Recovery Evaluation in DC Rail Networks
         by R. Barrero, O. Hegazy, P. Lataire, T. Coosemans, J. Van Mierlo

         Vol. 4. n. 6, pp. 2985-3003


Abstract - This article presents a multi-train simulation tool based on quasi-static averaged models of vehicles and a dynamic model of the DC network. It models the interactions and energy exchange among vehicles running on the line and shows the influence of the traffic density on the vehicles energy regeneration and substations energy consumption.The tool can simulate both conventional and modern rail networks equipped with different energy saving technologies such as on-board and wayside energy storage systems, hybrid trains and reversible substations. Thanks to the detailed models, the tool can be used to both study any conventional rail DC network and to design and predict the best solution in terms of energy recovery for a particular network.The models of the complete system have been validated with measurements taken on metro vehicles running in regular service under different traffic conditions. Simulation results show a good match between measurements and simulations.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Multi-Train Simulation, Energy Recovery, Reversible Substation, Energy Storage.



International Review on Modelling and Simulations - Papers (Part B)



go to top   Rule-Based Expert System for PQ Disturbance Classification Using S-Transform and Support Vector Machines
         by M. A. Hannan, Tea Chiang Wei, Alex Wenda

         Vol. 4. n. 6, pp. 3004-3011


Abstract - This paper presents a rule-based expert system for automatic identification and classification of PQ disturbances by combining the improved S-transform and SVM. The combined tools are used to integrate the computation process and extracted features to formulate rules for classification of the PQ disturbances.Rule formulataion is developed by comparing standard deviation value of a disturbance signal that is obtained from the S-transform analysis. SVM technique is used for data classification and regression for training and testing the class level and control feature parameters, respectively.Thus, based on the distinctive features through SVM, the S-Transform formulated appropriate rules and features contour that can easily be classify the PQ disturbances.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Rule-Based Expert System, PQ Disturbances, Classification, S-Transform, SVM.



go to top   Smart AC-DC Power System with Voltage Fluctuation Control and Fault Analysis
         by A. Thamilmaran, P. Vijayapriya, R. Suresh, Dr. D. P. Kothari

         Vol. 4. n. 6, pp. 3012-3018


Abstract - Due to continuous exploitation of oil and gas reserves combined with the effect of global warming has brought renewed interest in alternative energy sources. Renewable power resources are safe, clean, and abundant in nature. Recent research and development in renewable power generation techniques such as photovoltaic, wind has shown excellent potential towards building a sustainable energy economy in the next decade. The energy sources and connecters need to be integrated to meet sustained load demand while considering the natural whether conditions. The paper focuses on the combination of wind and photovoltaic system to ensure that system performs under all conditions. The system consists of a wind generator and alternate energy conversion systems such as PV cells. However, due to the power fluctuation of renewable energy sources, voltage and frequency deviations are occurred in island power systems whose ability to maintain stable supply–demand balance is low. Therefore, it is necessary to control the system frequency and voltage. From this viewpoint, a smart grid, which maintains stable supply–demand balance is necessary. The proposed system has advantages of both dc and ac grids. Output from the wind, PV cell and battery are maintained at same voltage and connected to the common DC bus while the conventional power supply modeled as three phase voltage source and several controllable loads of different capacities are connected to the AC bus. The system is analyzed under fault conditions. The Model is developed using MATLAB- Simulink.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Wind Generator, PV Cell, Hybrid System, DC Grid, Controllable Loads.



go to top   Design and Implementation of a PLC Based Monitoring and Control System for Reactive Power Compensation System
         by Ramazan Bayindir, Orhan Kaplan, Lokman Baran

         Vol. 4. n. 6, pp. 3019-3028


Abstract - In this study, a reactive power compensation system has been implemented using a programmable logic controller (PLC). The four induction motors, which are used as reactive power consumers, are run or stopped by PLC in the power system. Thus the power system containing more than one reactive power consumer has been prepared. The current and the voltage of the power system are measured and then processed in the PLC to calculate the power factor of the system. The power factor calculation procedure is a novel algorithm developed by the authors. The required reactive power is provided by switching the capacitor groups automatically using the developed software. In addition, the developed system can protect the induction motors against some possible problems, such as overcurrent, high/low voltage, and phase sequence error. Owing to the improved computer interface, starting and stopping of the motors and monitoring of the parameters of the power system could be easily achieved using the computer. Furthermore, it has been shown that the proposed system is very flexible and expandable for different applications. In the study the most important disadvantage is that the grid current waveform is destroyed after reactive power compensation since the motors used as load do not draw a complete sinusoidal current from the grid.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Power Factor, Reactive Power Compensation Capacitors, PLC.



go to top   The Roles of Static VAr Compensators in Smart Grids: a General Theory using Power Analysis
         by Félix R. Quintela, Roberto C. Redondo, Norberto R. Melchor, Juan M. G. Arévalo

         Vol. 4. n. 6, pp. 3029-3036


Abstract - Static VAr Compensators (SVCs) owe their name to their ability to compensate reactive power, but they can also perform other useful functions on smart grids in order to improve the electric power supply. This paper shows a general SVC theory based on the power analysis, which leads to a system of linear equations that completely dictates the behaviors of SVCs. This equation system can be used to deduce all the roles a SVC can play in electrical systems, and to determine its reactance values for each of those roles. As an example, the design values of SVCs are obtained for some of these applications. Experimental tests are also included.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Smart Grid, Three-Phase Load Balance, SVC, Power and Energy Losses, Phase-To-Phase Load.



go to top   An Enhanced Control Strategy for SSFCL in Limiting Fault Current in the Distribution System
         by M A Hannan

         Vol. 4. n. 6, pp. 3037-3043


Abstract - This paper deals with the modeling and simulations of solid-state fault current limiter (SSFCL) for providing credible solutions to power quality problems. An enhanced control strategy has been developed for instantaneous detection of overcurrent and limitation of the fault currents in the distribution system. The modeling of these devices is based on graphic models using the electromagnetic transient simulation program PSCAD/EMTDC.An extensive investigation are made to evaluate the performance of the SSFCL in limiting fault currents for a system with induction motor load and its capability in compensating voltage sags and effect of changing FCL parameters. It was observed that the impact of the induction motor load on the performance of the SSFCL proves that the limiting fault currents are greater as compared to the system with static loads. The current limiting reactor of the SSFCL plays an important role in compensating voltage sags caused by the different types of faults. Thus, the results of the SSFCL proved that it is a suitable device for limiting fault current within 2 ms which is the tolerable limit of the system. The developed models will be useful for further power quality studies in a distribution system.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Control Strategy, SSFCL, Fault Current, Distribution System.



go to top   Static and Dynamic Stability Analysis of Distributed Energy Resources Components with Storage Devices and Loads for Smart Grids
         by L. Mihet-Popa, V. Groza

         Vol. 4. n. 6, pp. 3044-3050


Abstract - The distributed energy resources (DER) contains several technologies, such as diesel engines, small wind turbines, photovoltaic inverters, etc. The control of DER components with storage devices and (controllable) loads, such as batteries, capacitors, dump loads, are central to the concept of the Smart Grids (SGs). A SG can operate interconnected to the main distribution grid or in islanded mode. This paper presents experimental tests for static and dynamic stability analysis carried out in a dedicated laboratory for research in distributed control and smart grid with a high share of renewable energy production. Moreover to point out, on a laboratory scale, the coupling between DR and storage and to effectively compensate wind fluctuations a number of tests have been done. In order to find out the parameters of various types of DER components for dynamic simulation models a number of tests are required under different operation modes and loads. The testing reporting here includes three modes of operation: stand alone, parallel/hybrid and grid connection.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Distributed Energy Resources, Smart-Grid, Static And Dynamic Stability Analysis.



go to top   Estimation of Nonsinusoidal Operating Conditions in Electric Networks on the Basis of Measurements
         by A.Z.Gamm, L.I.Kovernikova

         Vol. 4. n. 6, pp. 3051-3058


Abstract - Consideration is given to an algorithm intended for calculation of electric network nonsinusoidal operating conditions by the state estimation method. The state estimation vector is formed by the magnitudes and phases of harmonic voltages including fundamental voltage. The new generation measurement devices (Phasor Measurement Units) are proposed to synchronously measure operating parameters at different points of electric network. The suggested algorithm was used to create a program for calculations. The authors present the calculation results based on the data obtained in the experiments on the physical model of electric network.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Power Quality, Nonsinusoidal Condition, State Estimation Method.



go to top   Practical Voltage Sag Mitigation Techniques – a Key Success Factor for Smart Grid Implementation in Provincial Electricity Authority
         by S. Songsiri, S. Sirisumrannukul

         Vol. 4. n. 6, pp. 3059-3069


Abstract - This paper presents a practical implementation to mitigate voltage sag problems in Provincial Electricity Authority (PEA)’s distribution systems in the Smart Grid environment. PEA is developing a smart grid road map for next 20 years and the improvement of power quality is one of the main important issues in the roadmap. To become a voltage sag-free system, three methods are proposed for PEA: reduction of fault clearing time by revision of protection scheme, insertion of neutral grounding resistance, and resonant grounding. The advantages and disadvantages of these techniques are illustrated by a 115/22 kV substation with two outgoing feeders. The study results from transient simulations with different fault locations by ATP-EMTP reveal that these three techniques are capable of mitigating voltage sags originated by a single-line-to-ground short circuit. However, although reducing fault clearing time and installing a neutral grounding resistance are cost-effective, the customers connected to the faulted feeder downstream to the fault are still disconnected. To avoid sustained interruption for which the outage cost is of concern while respecting the acceptable criteria defined by the ITIC curve, the resonant grounding is introduced based on the principle of compensation between capacitive current generated by the stray shunt capacitance of feeder and inductive current generated by a Peterson coil.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Voltage Sag Mitigation, Smart Grids, Distribution Systems, Power Quality.



go to top   Microgrid Sizing Along with Reliability Consideration Using Particle Swarm Optimization
           by Arash Navaeefard, Roozbeh Kamali, S.M.Moghddas Tafreshi, Omid Babayi

           Vol. 4. n. 6, pp. 3070-3078


Abstract - The major application of the MicroGrid (MG) is in remote areas where utility lines are uneconomical to install due to terrain, the right-of-way difficulties or the environmental concerns. In this paper a novel intelligent method is applied to the problem of sizing in a MG such that demand of residential area is provided, and reliability index is considered as a constraint. In this MG, power generators are photovoltaic (PV) /wind turbine, and battery bank is used as an energy storage system. PSO algorithm has been used to optimize the cost function, and has been simulated in MATLAB for justification purpose.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Wind Turbine, Photovoltaic, Battery Bank, Microgrid, Optimal Sizing, Reliability.



go to top   Multi-objective Optimal Operation of Microgrid with an Efficient Stochastic Algorithm Considering Uncertainty of Wind Power
         by B. Khorramdel, H. Khorramdel, H. Marzooghi

         Vol. 4. n. 6, pp. 3079-3089


Abstract - Due to the rapid growth of utilization of Distributed Generations (DGs) in microgrids, their different aspects have been the concern of recent research. In addition, the penetration of wind power is growing rapidly in microgrids around the world and depends on the capacity of the wind farms; it may participate in microgrids. In such a case, the volatile nature of wind power affects the operation of microgrids in many different aspects. Considering the impact of wind power volatility on microgrid operation and existence of some Electronically Interfaced DGs (EIDGs) in a microgrid, this paper proposes a new Optimal Power Flow (OPF) algorithm which uses multiobjective nonlinear programming technique and includes three stages. This algorithm determines the optimal control variables of each EIDG, such as PQ, PV and a new model of DGs which is named Q-sharing DGs in a microgrid to achieve the minimum power loss and improving the Voltage Profile Index (VPI). Considering some probable wind speeds, in the third stage the best control variables are acquired to schedule of reactive power through using results of two previous stages. The proposed algorithm is applied to IEEE 34-bus distribution test system and numerical studies show satisfactory results.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Distributed Generations, Microgrid, Optimal Power Flow, Q-sharing DGs, Reactive Power Control, Stochastic Algorithm.



go to top   Improving Reactive Power Margin for Voltage Stability Enhancement Using FACTS Devices
         by K. Chandrasekar, N. V. Ramana

         Vol. 4. n. 6, pp. 3090-3097


Abstract - Reactive Power Margin (RPM) is an indicator of power system Voltage Stability (VS). With this perspective, this paper presents the application of Differential Evolution (DE) algorithm for Reactive Power Margin (RPM) improvement using FACTS devices. Conventionally, RPM is evaluated using V-Q curve analysis which suffers from the drawback of conservative results due to step increment in voltage. This drawback is eliminated in this paper by utilizing DE to directly search the voltage value instead of incrementing it for RPM assessment while finding the optimal location and settings of FACTS devices for RPM improvement. Further to improve computational efficacy, power flow is performed using Broyden Shamanski method with Sherman Morrison formula (BSS) instead of a conventional Newton Raphson (NR) power flow. Simulation tests are carried out on IEEE 14, 30, 57 and 118 bus test systems. Results indicate that the proposed approach enhances RPM and improves the computational efficacy better when compared to the conventional approach.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Differential Evolution, FACTS Devices, Reactive Power Margin, V – Q Curve, Voltage Stability.



go to top   Generation Reliability Assessment in Power Markets Using MCS and Neural Networks
         by Hossein Haroonabadi, Hassan Barati

         Vol. 4. n. 6, pp. 3098-3103


Abstract - Deregulation policy has caused some changes in the concepts of power systems reliability assessment and enhancement. In this paper, generation reliability comparison in three kinds of power markets is considered: Perfect competition, Monopoly and Oligopoly power markets. Because of power market and generators’ forced outages stochastic behavior, Monte Carlo Simulation (MCS) is used for reliability evaluation. Also, for creating a unique structure, a feed forward neural network which has similar numerical results in comparison with MCS results, is used for generation reliability evaluation. The proposed method is assessed on IEEE-Reliability Test System with satisfactory results. In all cases, generation reliability indices are evaluated with different reserve margins and various load levels. It will be shown that if price elasticity of demand increases, reliability will improve. Also, comparison of perfect competition and monopoly power markets shows that whatever market becomes more concentrated, reliability will improve. In an oligopoly power market, if a company’s share in the market increases or price elasticity decreases, the company can mark up the price more than before. 
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Generation Reliability, Power Markets, Monte Carlo Simulation, Neural Networks.



go to top   Security Constrained Unit Commitment in Iran's Electricity Market
         by M. S. Javadi, A. Meskarbashi, R. Azami, Gh. Hematipour, A. Javadinasab

         Vol. 4. n. 6, pp. 3104-3112


Abstract - This paper surveys on Security Constrained Unit Commitment (SCUC) based on Iran's Electricity Regulation (IER). Day-Ahead (DA) power market and operation of the Iran's national grid is addressed considering the market regulation and operation rules which is managed by Iran Grid Management Company (IGMC) as Independent System Operator (ISO). National grid dispatching control center and data exchanging between main supervisory control and relevant Area Control Centers (AOC) are described in this paper. The market and operating infrastructure of the national grid is also expressed. Energy market clearing mechanism in Iran electricity market is based on Pay-as-Bid (PAB) which imposes some concerns for market operator and participants. The DA power market clearing which implemented in energy market satisfied the real constraints and feasibility of the algorithm is proved by the simulation studied.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Iran's Electricity Market, Pay-as-Bid Mechanism, Security Constraint Unit Commitment.



go to top   Reconfiguration of Distribution Network with Dispersed Generations Based on Ant Colony Algorithm
         by M. J. Kasaei, H. Norouzi

         Vol. 4. n. 6, pp. 3113-3118


Abstract - This paper presents one of applications of the Ant colony algorithm method for the reconfiguration of distribution networks with dispersed generation (DG) to reduce power losses and voltage profile improvement .The configuration optimization problem of distribution networks is a combination optimization with a large search space involved the operational constraints of the distribution. Dispersed generation sources such as fuel cells, solar cells, wind mills and micro gas turbines can be strategically allocated in distribution networks for reducing power losses, network reinforcement, improving network efficiency and reliability. The performance of the proposed method was investigated on two distribution networks consisting of 16 and 10 buses.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Distribution Network, Dispersed Generation, Reconfiguration, Loss Reduction, Ant Colony.



go to top   Line Stability Index for Steady State Stability Enhancement Using FACTS Device
         by C. Subramani, Subhransu Sekhar Dash, A. F. Zobaa, Vivek Kumar

         Vol. 4. n. 6, pp. 3119-3124


Abstract - Estimating the margin in the loadability of the power system is essential in the real time voltage stability assessment. Voltage stability is currently one of the most important research areas in the field of electrical power system. The condition of voltage stability in a power system can be known using Voltage Stability Indices (Lmn). The loading margin is one of the most widely known and accepted Lmn. Voltage Stability Indices can be useful for estimating the distance from the current operating point to voltage collapse point. The indices can either reveal the critical bus of a power system or the stability of each line connected between two buses in an interconnected network or evaluate the voltage stability margins of a system. Flexible Alternating Current Transmission Systems (FACTS) devices have been proposed as an effective solution for controlling power flow and regulating bus voltage in electrical power systems, resulting in an increased transfer capability, low system losses, and improved stability. However to what extent the performance of FACTS devices can be brought out highly depends upon the location and the parameters of these devices. Unified Power Flow Controller (UPFC) is the most promising FACTS device for power flow control. The performance of this index is presented and the effectiveness of the analyzed methods is demonstrated through simulation studies in IEEE 14 bus reliability test systems.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Loading Margin, Voltage Stability Assessment, Contingency Analysis, Voltage Collapse, Voltage Stability Index, UPFC Device, Stability Enhancement.



go to top   Harmonic Analysis of Power Systems in order to Network Conversion
         by R. Shariatinasab, M. Akbari

         Vol. 4. n. 6, pp. 3125-3134


Abstract - Conversion of 3-phase single-circuit (3PSC) to 3-phase double-circuit (3PDC) and 6-phase single-circuit (6PSC) transmission line is a well known method to increase the power transfer capability of the network. The constraints using to decide on conversion type are usually network total loss and desirable voltage limits; while the harmonic effects are omitted. However, harmonics lead to undesirable power quality and increase total loss of the network. Thereby, in order to obtain the accurate result to adopt an optimal scheme for network conversion, harmonics should also be considered. In this paper a harmonic analysis due to the conversion of 3PSC to 3PDC and 6PSC network is performed. The analysis is applied to a real study system by conversion of the entire and just one of the existing lines of the network, separately. The results show that, when harmonic effects are considered or omitted, the criteria needed to make a decision on the options existed for network conversion could change. Due to the obtained results, telephone influence factor (TIF) of currents and total harmonic distortion (THD) of voltages are dependent on conversion type together with the harmonic sources of the network. However, in 6PSC conversion compared to 3PDC conversion type, the number of resonances is increased and propagation of high frequency disturbances is decreased.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Harmonic Analysis, Network Conversion, Current TIF, Voltage THD.



go to top   Harmonics Reduction Techniques – a Survey
           by Hadeed Ahmed Sher, Ali M. Eltamaly

           Vol. 4. n. 6, pp. 3135-3147


Abstract - With the growing progress in the field of power electronics the issue of power quality come up with an important area of research. The unsaturated progress of power electronics has certain pros and cons also. The most vital among the disadvantages of power electronic loads are the production of harmonics. A lot of work is going on in the scientific community for the enhancement of power quality. Several strategies have been devised to reduce harmonics. With the advent of artificial intelligence (AI) and expert system (ES) based techniques, the researchers are better able to optimize the harmonic filters. Active filters have been surveyed by some researchers, however, so far no collective survey on harmonic reduction techniques is available. In an attempt to contribute with the scientific community, this paper discusses the major harmonic reduction techniques available in literature.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Harmonics, Passive Filters, Current Reinjection, Active Filters, Power Quality.



go to top   Optimal Allocation and Sizing of DG on Distributed Network for Voltage Profile Improvement and Voltage Imbalance Reduction with Genetic Algorithm
         by M. Sarvi, S. M. Torabi, A. Fallahpisheh

         Vol. 4. n. 6, pp. 3148-3154


Abstract - Progresses made in distributed generation (DG) technologies and utilizing them on distribution network, prepare an opportunity to impart of their utilizing benefits in operation improvement of distribution networks. The benefits of using these resources are such as loss reduction voltage profile improvement, network reliability improvement, and etc. Progresses made in distributed generation (DG) technologies and utilizing them on distribution network, prepare an opportunity to impart of their utilizing benefits in operation improvement of distribution networks. The benefits of using these resources are such as network reliability improvement, loss reduction, voltage profile improvement and etc. To achieve the desired aims, sitting allocation and sizing problem that means determining capacity, number and location of DG is very important. In this paper, an optimal DG resource sitting via genetic algorithm is proposed in order to improve voltage amplitude and imbalance on distribution networks. In other words, objective is to adjust bus voltage amplitude to desired values (usually nominal values) along with voltage imbalance reduction via optimal DG resource sitting. The effects of DG resource on loss and voltage profile within distribution network are investigated and then the proper load flow on the presence of DG resources is presented. Simulation results are performed in the MATLAB software. Two networks (the symmetrical IEEE 13 buses and asymmetrical 26 buses) are investigated and their results are analyzed. The accuracy and benefit of the proposed method for determination of capacity, number and location has been shown in simulation results.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Distributed Generation, Optimal Allocation and Sizing, Voltage Profile, Voltage Imbalance.



go to top   Proposed Optimal Multiplier Load Flow Method for the Maximum Loading Point Search in Ill Conditioned System
         by A. Shahriari, H. Mokhlis, A.H.A. Bakar, H.A. Illias

         Vol. 4. n. 6, pp. 3155-3163


Abstract - The accuracy of the classical optimal multiplier power flow method in the feasible and infeasible operation zone in ill conditioned system is relevant to the exact value of the Maximum Loading Point (MLP). The optimal multipliers are forced to meet each other at MLP. Therefore, there is no guarantee that the optimal multiplier leads to a voltage collapse point of a system at MLP. This paper presents a new robust, simple and fast approach based on the optimal multiplier load flow method (OMLFM) to detect MLP. The proposed method introduces the divergence of the second order terms of OMPFM as a detector to obtain MLP. The advantages of this method compares to previous techniques are: 1 - Calculation of low voltage solution of a system and their corresponding MLPs simultaneously for the boundary zone of an ill conditioned and unsolvable system. 2 - No new computation for OMLFM in obtaining the MLP. 3 - The utilization of fully polar coordinate system instead of rectangular coordinate, which further simplifies the task and by keeping PV type buses, this method is more appropriate for power flow solution in ill conditioned system.
This method is validated by using 300 IEEE bus system.

Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Maximum Loading Point, Low Voltage Solution, Ill Conditioned System.



go to top   Capacitor and DG Placement in Distribution System by Genetic Algorithm and PSO
         by M. Sarvi, S. M. Torabi, M. R. Salimian

         Vol. 4. n. 6, pp. 3164-3168


Abstract - Distributed generation (DG) and capacitors are important tools in distribution system which can be used to improve the system voltage and reduce system losses. Optimal sizing and siting of DG and capacitors must be determined in distribution system. In this paper, we use genetic algorithm and PSO for Optimal sizing and siting of DG and capacitors. Effect of DG and capacitor on loss reduction, reactive generation and voltage regulation are compared. Also genetic and PSO are compared.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  DG, Capacitor, Loss, Reactive, Voltage.



go to top   Optimization of Distributed Generation Number, Location and Sizing for Reliability Improvement and Line Loss Reduction Using PSO
         by Y. Bostani Amlashi, H. Afrakhte

         Vol. 4. n. 6, pp. 3169-3174

Abstract - Distributed Generation (DG) is providing the electricity power near the point of consumption by omitting the incremental costs. There is an increasing trend towards DG application in power systems because of compensating the load congestion, improving the capacity of transmission lines, increasing power quality and greater reliability. Accordingly in this study a new methodology has been presented that uses a particle swarm optimization (PSO) algorithm for specifying the reliability improvement and power loss reduction. By means of this method can determine the optimal number, location and sizing of distributed generation unites in a radial distribution system. Reliability Indexes is also enhanced while the losses decrease in the network. The submitted method is tested on standard IEEE 33-bus test system and the results are presented to exhibit the efficiency of the proposed procedure.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Distributed Generation; Distribution Networks; Particle Swarm Optimization (PSO); Power Loss; Reliability.



go to top   Design of TCSC Controller for Improvement of Transient Stability of a Power System
         by P.Nagaraju Mandadi, Dr. K.Dhanvanthri

         Vol. 4. n. 6, pp. 3175-3179


Abstract - FACTS controllers , because of their fast response, improves the Transient Stability limit of a power System by giving away the excess energy gained by the generators in the event of disturbances due to faults. Thyristor controlled Series Compensator (TCSC) is an important device in FACTS family and is widely recognized as an effective means to solve the power system stability problem. In the present work, a SIMULINK setup has been developed by means of which the parameters of TCSC controller along with a Power System Stabilizer (PSS) can be selected and designed to get a desired time response. The developed SIMILINK setup is Robust, Easy and Simple which can be used to determine the parameters very quickly thereby saving a lot of time.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Transient Stability, FACTS Controllers, Thyristor Controlled Series Compensator (TCSC), Power System Stabilizer (PSS), Simulink, Matlab.



go to top   Locating and Parameter Setting of Unified Power Flow Controller via Harmony Search Algorithm
         by A. Sharifi Nasab Anari, R. Ghadiri Anari, S. Soleymani, M. Ghasemi Nezhad

         Vol. 4. n. 6, pp. 3180-3187


Abstract - This paper proposes a Harmony Search Algorithm (HSA) to achieve the optimal location and proper parameters settings of Unified Power Flow Controller (UPFC) for congestion Management in restructured electricity market. Having a great flexibility, UPFC can control the active and reactive power flow and bus voltages, simultaneously. Two different objective functions are considered in this study. In the first one, minimization of total operating cost including congestion rent and total generation cost is considered as the objective function. In the second one, objective is minimization of system loss. In order to verify and validate the effectiveness of the proposed method, IEEE 14-bus test system and IEEE Reliability Test System (RTS) are employed. The results for IEEE RTS are compared with those obtained by PSO algorithm, reported in the literature. The results show that the congestion cost and loss of the power transmission system can be effectively reduced through the optimal location and proper parameters selection of the UPFC.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Power System Loss, Unified Power Flow Controller (UPFC), Harmony Search Algorithm, Congestion Management.



go to top   Thermal Unit Commitment Scheduling Problem in Utility System by Simulated Annealing Embedded Evolutionary Programming Method
         by Nimain Charan Nayak, C.Christober Asir Rajan

         Vol. 4. n. 6, pp. 3188-3194


Abstract - This paper presents a new approach to solving the short-term thermal unit commitment scheduling problem in utility system using Simulated Annealing Embedded Evolutionary Programming Method. The objective of this paper is to find the generation scheduling such that the total operating cost can be minimized, when subjected to a variety of constraints. A 7-Unit utility power system with twelve generating units in India demonstrates the effectiveness of the proposed approach; extensive studies have also been performed for different IEEE test systems consist of 10, 26 and 34 Units. Numerical results are shown comparing the cost solutions and computation time obtained by using the Evolutionary Programming method and other conventional methods like Dynamic Programming, Legrangian Relaxation and Simulated Annealing in reaching proper unit commitment.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Unit Commitment, Simulated Annealing, Evolutionary Programming, Dynamic Pogramming, Legrangian Relaxation.



go to top   Electric Field Computation for Functionally Gradient Material Spacer Insulator for Gas Insulated Bus Duct
         by Gopichand Naik.M, Amarnath.J , Kamakshiah.S

         Vol. 4. n. 6, pp. 3195-3200


Abstract - The Gas Insulated Substation (GIS) have various advantages like compactness, immunity from environmental conditions, high operational reliability, low maintenance cost. In a number of GIS installations, the main design considerations involved in gas insulated equipment are at cone insulator, gas and metal interface. Hence there is a need for control of electric stress in order to reduce internal discharges, surface discharges to the enclosure surface. In conventional approach, in order to reduce such distortion of electric field, many techniques applied like, control of the spacer shape, additional shielding of electrodes for relaxation of electric field around spacer and low permittivity material of spacer, etc., from this point of view the new techniques of Functionally Gradient Material (FGM) spacer has been proposed in this paper. The applicability of FGM spacer for gas insulated power apparatus has been verified. In the FGM spacer, a spatial distribution of permittivity for the control of the electric field distribution in and around the spacer is used. The electric field calculations for several types of FGM spacers have been carried out using Finite Element Method (FEM). The electric field distribution along the radial distance of the spacer insulator has been obtained for various FGM materials and results are compared.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  FGM, FEM, Electric Field Distribution, Modelling of Cone Spacer.



go to top   Preventive and Curative Strategies Based on Fuzzy Logic Used for Voltage Stabilization of an Electrical Network
         by Moez Ben Hessine, Sahbi Marrouchi, Souad Chebbi, Houda Jouini, Rabeh Abbassi

         Vol. 4. n. 6, pp. 3201-3207


Abstract - In this paper, we present the new preventive and curative strategy developments used to a power system stability control implemented in the network Test IEEE 14 buses. This development is in order to show that this type of control ensures maintenance of the network in a study state by using an adequate control taking into account of the studied network state variable instantaneous specificities in the presence of a disturbed mode. The best identification of algebraic and dynamic state variable variation margins of the studied system specifically in disturbed mode will be at the origin of new control strategy integration able to contribute effectively to a network new study state establishment. Our control strategies are proposed to estimate of the electric quantity variation margins (active power and reactive power) injected at any bus particularly in case of rare event appearances. We exploited fuzzy controllers in order to generate an adequate command vector taken as an optimized action to prevent such electrical network situation.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  FACTS, UPFC, Fuzzy Logic, PSRF, NSRF, PLL, PWM, Positive Sequence, Negative Sequence, Load Shedding, Sensitivity.



go to top   Different Methodologies to Determine Break Point Relays in a Power System Protection
         by Joymala Moirangthem, S. S. Dash, A. F. Zobaa

         Vol. 4. n. 6, pp. 3208-3213


Abstract - Coordinating a system of directional relay is very complicated due to the typical loop structure of the transmission system, and also changing the setting parameters of one relay for obtaining coordination for all the relevant fault current pairs can disturb the proper coordination of the already checked relay pairs. Arbitrary starting relay locations and arbitrary consideration of relay sequence to set and coordinate relays will result in navigating loops many times, and usually result in futile attempts to achieve system-wide relay coordination. This paper has listed out the different methodologies and techniques to determine the break point set to provide accurate directional relay coordination. And also new technique Particle swarm optimization has been introduced and implemented to determine the break point relays in this paper. This work will be useful for the researchers to find the relevant references to enhance the research work in future.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Break Point Set (BPS), Looped System, Particle Swarm Optimization (PSO), Relay Coordination, Relay Settings.



go to top   A Review of Methodologies for Fault Detection and Location in Distribution Power Networks
         by A.C. Adewole, R. Tzoneva

         Vol. 4. n. 6, pp. 3214-3231


Abstract - The widespread deregulation and restructuring of electric power utilities throughout the world and the consequent increase in competition amongst utility companies has brought about the desire for improved economic efficiency of electric utilities and the provision of better service to energy consumers. Thus, there is a growing research interest in power system distribution network fault detection and diagnostic techniques. Transmission and distribution lines are subject to faults caused by lightning, storm, snow, insulation breakdown, birds, etc. Fault detection and diagnosis is a central component of Abnormal Event Management (AEM). The early detection and diagnosis of these faults can expedite the restoration and return to service of this lines. This paper provides a comprehensive review of research work on the various methodologies in power system distribution network fault detection, fault classification, faulted section identification, and fault location.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Artificial Neural Network, Distribution Network, Fault Detection, Fault Location, Power System Protection.



International Review on Modelling and Simulations - Papers (Part C)




go to top   Effect of Crack Faces Opening Mechanisms on the Combined Stress Intensity Factors under Bending and Torsion Moments
         by A. E Ismail, A.K Ariffin, S. Abdullah, M.J Ghazali

         Vol. 4. n. 6, pp. 3232-3238


Abstract - This paper presents a numerical investigation on the effect of crack faces opening mechanisms on the combined stress intensity factors for surface cracks in round bars. A full finite element model was constructed due to the non-symmetrical analysis involved. Bending and torsion moments were remotely applied to the model and the stress intensity factors were calculated along the crack front. The stress intensity factors were also combined explicitly through the equivalent stress intensity factor method and then compared with the results obtained from the finite element analysis under combined loadings. There were high discrepancies between the results especially when the bending moment dominated the stress condition. From the deformed mesh observation, it was found that the discrepancies were due to the differences in crack face interaction mechanisms and thus affecting the combined stress intensity factor calculations.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Combined Stress Intensity Factors, Finite Element Analysis, Surface Cracks.



go to top   EMTP-RV Model of Hydraulic Digital Governor
         by M. Dabro, I. Jurić-Grgić, R. Lucić

         Vol. 4. n. 6, pp. 3239-3242


Abstract - This paper presents EMTP-RV model of hydraulic digital governor. Based on block scheme of a digital turbine control system, a novel EMTP-RV model of hydraulic digital governor for stability studies has been developed. Developing of hydraulic digital governor is an important step in achieving a fully integrated system for stability studies. The simulated transient response characteristics of a digital governor, obtained by the proposed model, give us much more realistic response comparing to the conventional hydraulic governor model (IEEE Type 3 turbine and governor system).
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  : Hydraulic Digital Governor Model, EMTP-RV.



go to top   Emission Controlled Security Constrained Unit Commitment Considering Hydro-Thermal Generation Units
         by M. S. Javadi, A. Meskarbashi, R. Azami, Gh. Hematipour, A. Javadinasab

         Vol. 4. n. 6, pp. 3243-3250


Abstract - In this paper, Emission Controlled Security Constrained Unit Commitment (ECSCUC) model is proposed in power system. This model consists of a closed-loop modified Unit Commitment (UC) and Security-constrained Optimal Power Flow (SCOPF). An emission controlled formulation is developed to improve the economic-environment conditions of operation of power system. The objective of this ECSCUC model is to obtain the maximum social welfare-based system operating cost while maintaining the system security also considering the environmental impacts. This paper proposed a multi-stage multi-objective mixed-integer nonlinear programming (MINLP) to minimize system operation cost. In this paper, multi-reservoir cascaded hydro plant with time delay and thermal plants are considered for maintaining the demand. The presented formulation treats emission controlled security constrained unit commitment of hydrothermal power system which attempts to optimize both cost and emission simultaneously. The numerical examples exhibit the effectiveness of the proposed model in recent competitive electricity markets.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Hydro-Thermal Generation Units, Emission controlled Security Constrained Unit Commitment, Cascaded reservoirs.


go to top  Development of an Inertial Measurement System for Electronic Stability Control Applications
           by V. Mahboubi, M. Khoddam, H.Badri, A.Ebrahimi

           Vol. 4. n. 6, pp. 3251-3260


Abstract - In this scheme, after assessing the requirements of electronic stability systems, in addition to a sensor set including a yaw-rate sensor, an accelerometer, a thermal sensor and an speed sensor, a 32-bit microcontroller based control system was designed in which the major necessities for data collecting and rapid processing of such a typical system could be performed. Furthermore, hardware capabilities for implementing the control algorithms using appropriate actuators when installing on a mechanical system was considered. Simultaneously, system is able to connect through the serial interfaces to the more powerful computers and processors for more complicated analysis. Moreover, for evaluating the performance of the designed system, a mechanical test-bench was designed and the obtained data was compared with the computer simulations. Results show that the designed inertial measurement system meets the required specifications of speed, efficiency and reliability.
publication by IREE.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Gyroscope, Accelerometer, Microcontroller, Crank-Rocker Mechanism, Electronic Stability Control.



go to top   Selecting Suitable Journal in Digital Libraries with Web Usage Mining
         by Farzam Yousefi, Sayed Mehran Sharafi, Mohammad Ali Nematbakhsh

         Vol. 4. n. 6, pp. 3261-3272


Abstract - One of the existing sources in digital libraries is electronic journals. Librarians use e-journals’ usage data for many practical applications (e.g. to begin or end subscriptions). Publishers and vendors, who have these data, usually don’t share them with the librarians or represent only that data which support their sales products. One possible method for evaluation is preparing monitoring system and logging the data related to users’ interactions with digital library and collecting transactions and using data analyzing techniques. In this research web usage mining method has been used. Since server log files don’t contain precise information and details of users’ interactions, this research is going to use client side data, special new category of data called Intentional Browsing Data(IBD), for improving quality of discovered knowledge and exploit IBD as a criterion for determining the journals’ desirability in students’ viewpoint.The obtained knowledge from analyzing discovered patterns can be used to make decision in journal management and it is a new method in this field. Digital library of Islamic Azad University of Najaf Abad (IAUN) is considered as a practical domain of this research. By using obtained patterns of mining and analyzing collected data, a model is presented to identify desirability of journal according to students’ viewpoint.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Digital Libraries, Intentional Browsing Data, Usage Data, Web Usage Mining.



go to top   Matlab Based Fluid Level Control Using Pid and Fuzzy Logic Controllers
         by Abdurrahman Ünsal, Ahmet Kabul

         Vol. 4. n. 6, pp. 3273-3278


Abstract - In this paper, fluid level control system was designed by using PID control and fuzzy logic control algorithms in MATLAB&Simulink environment. The communication between the hardware of the system and Simulink program was established by using automatic code production tool which is a part of the MATLAB Real Time Workshop toolboxes. PID control and fuzzy logic control algorithms were applied to the designed system. The comparison was made between these two methods. The results of the methods are compared. The experimental results show that the system reaches its steady state position when controlled by using fuzzy logic method.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Fluid Level Control, Fuzzy Logic Controller, PID Controller, Real Time Control.



go to top   A New Time-Domain H2-Norm Robust Fault Detection Filter for a Drum Boiler System through an LMI Approach
         by L. Khoshnevisan

         Vol. 4. n. 6, pp. 3279-3284


Abstract - One of the robust fault detection filter (RFDF) designing methods is based on H2-norm technique. The fundamental purpose of our study is to formulate the RFDF as a continuous robust H2-norm optimal design via a linear matrix inequality (LMI) through which the generated residual signals are robust against external disturbances and sensitive to faults simultaneously. The designed RFDF is continuous with the advantage of not mandating any transformation matrix and can directly be implemented to the time-domain original continuous model. Finally, the designed method is theoretically applied in a simulated model of a drum boiler operating in Synvendska Kraft AB Plant in Malmo, Sweden as a multivariable and strongly coupled system. It is illustrated that both sensor and actuator faults can robustly be detected as quickly as possible. Also sensor faults can be isolated through this procedure. To the best author's knowledge, this is the first time that the continuous H2-norm procedure is applied to detect actuator and sensor faults in a real boiler.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Boiler, Continuous H2-Norm Filter, Fault Detection, Linear Matrix Inequality, Robustness.



go to top   Fuel Cell and Solar Cell Hybrid System for Electrical Energy Generation
         by Sazzad Hossain, Farzana Sharmin, Mohiuddin Ahmad, I. Daut, M. A. Rashid

         Vol. 4. n. 6, pp. 3285-3291


Abstract - The storage of fossil fuel is being reduced rapidly to meet the present demand of energy all over the world. This will obviously result in the scarcity of usable fuel and hence energy in near future if we don’t find any viable solution very soon. Keeping this in mind, in our research paper we tried to find a possible solution of the energy crisis by developing a self-dependent power generation system. This is actually a hybrid system involving fuel cell and photovoltaic cell. Here, fuel cell is used as the base technology along with photovoltaic cell. We have utilized the hydrogen of water as the fuel source of fuel cell. The type and number of fuel cell stacks are so chosen that the system has the capability of providing necessary power requirements to a single house and can run by itself. The system described here is self-sufficient, environment friendly and safe. So it can play a vital role in solving the current energy problem quite satisfactorily.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Fuel Cell, Solar Cell, Electricity Generation, Converter Circuit.



go to top   Analyzing the Properties of Mobius Capacitors
         by Eraldo Banovac, Sejid Tesnjak, Darko Pavlovic

         Vol. 4. n. 6, pp. 3292-3300


Abstract - A theoretical foundation crucial for the physical processes that occur when the mobius capacitor is connected to the AC circuit is elaborated in the paper. A thin copper sheet and the PVC adhesive insulating tape are formed into different types of capacitors with the aim of researching the properties of the mobius capacitor, and testing its capacitance. The obtained capacitance values of the mobius capacitors with a pair of capacitive enclosures are stable, i.e. 3.7 pF and 4.0 pF for the first system, and 27.3 pF and 27.5 pF for the second system with the larger conductive strips. The properties of the mobius capacitor connected to an AC circuit are tested. The capacitance of the capacitor is calculated indirectly from the data obtained by measuring in the circuit. The paper points out that the mobius capacitor operates in the AC circuit likewise the parallel plate capacitor. The distance between the conductive strips is variable because of the elasticity of the dielectric strip, so that the capacitance of the capacitor is easily influenced by squeezing the strip or by gradual relaxation of the strip. Therefore, less precision of measurement of capacitance of the mobius capacitor in relation to the parallel plate capacitor is obtained, such as evident from the calculated values of the measurement errors.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  AC Circuit, Capacitance, Mobius Capacitor, Mobius Resistor.



go to top   Development of the Lightning Location Mapping System Using Fuzzy Logic Technique
         by A. Che Soh, R.Z. Abdul Rahman, M.Z.A. Ab. Kadir, N.S. Mohd Shif

         Vol. 4. n. 6, pp. 3301-3308


Abstract - The extremely high current produced from the lightning strike causes damages to the structures and fatalities to the human and live stock. Information regarding the lightning strikes and the location where it strikes is very useful for the utilities and building developers to select the best location of the project and the most suitable protection scheme for their system. The objective of this paper is to develop a Graphical User Interface (GUI) which can classify the lightning parameters of Peninsular Malaysia into three characteristics: region, level of current and type of lightning. The lightning strike parameters were obtained from the Global Lightning Network (GLN) of WSI Corporation, USA. Fuzzy logic method is used to classify the Peninsular Malaysia into eight regions with the use of ‘IF rule’ to determine the level of current and type of lightning strikes. The lightning parameters are classified into three levels of current: Low, Medium and High current with three different types of lightning: positive lightning, flash and negative lightning. The GUI of desired system is implemented using Microsoft Visual Basic which able to display the characterization process, statistical values, graphs and also the characteristics mapping for the corresponding regions.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Lightning, Lightning Parameters, Global Lightning Network, Fuzzy Method.



go to top   Gantry Robot Control with an Observer Based on a Subspace Identification with Multiple Steps Data
         by A. Bouhenna, A. Chenafa, A. Mansouri, A. Valera

         Vol. 4. n. 6, pp. 3309-3316


Abstract - When working with complex dynamic systems such as robotic systems needs to have a good estimate of the various terms that make them dynamic equation. From this estimate may provide various control algorithms (usually nonlinear) to compensate or take into account this dynamic equation. The problem that often arises is twofold: one part is not trivial to obtain the dynamic terms, and secondly, the control algorithms usually have high complexity, which may make it impossible to implement them in real time environments. This paper deals with obtaining the system state estimation using subspace-based system identification that not only get an estimate, but also can be used to calculate and implement control algorithms. This method has been validated on a gantry robot with multiple data sets. We have also designed a optimal control with a state observer using the estimated state space systems of the gantry robots. The results are very satisfactory.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Subspace Methods, System Identification, N4SID, MOESP, Discrete State Space, Gantry Robots, Optimal Control Algorithms, State Observer.



go to top   Designing Intelligent Advanced Controller for a Class of Large Scale Non-Canonical Nonlinear Systems: Observer-based Approach
         by R. Ghasemi, M.B. Menhaj

         Vol. 4. n. 6, pp. 3317-3326


Abstract - This paper introduces a new decentralized adaptive fuzzy controller for a class of large-scale nonlinear systems with unknown non-affine subsystems and unknown interconnections represented by nonlinear functions. The fuzzy system is used to represent the controller's structure. The stability of the closed loop system is guaranteed through Lyapunov stability analysis by introducing some adaptive rules derived appropriately. Simulation results easily highlight merits of the proposed controller.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Lyapunov Stability - Adaptive Control- Non-affine Nonlinear Systems- Large Scale Systems- Fuzzy Systems – Nonlinear Observer.



go to top   Adaptive Gain Scheduling Fuzzy Logic PID Controller in Load Frequency Control of Wind Diesel Micro Hydro Isolated Hybrid Power System
         by R.Dhanalakshmi, Dr.S.Palaniswami

         Vol. 4. n. 6, pp. 3327-3336


Abstract - This paper presents the design and analysis of Adaptive gain scheduling Fuzzy logic PID controller for load frequency control of an isolated wind-diesel micro hydro hybrid power system, to regulate the frequency deviation. Due to the sudden load changes and intermittent wind power, large frequency fluctuation problem can occur. An effective controller for maintaining the system frequency within acceptable range is significantly required . The fuzzy logic control has been applied to design LFC system. The proposed adaptive gain scheduling Fuzzy logic PID controller automatically tunes the coefficients Kp, Ki and Kd whenever there are load disturbances. Also, a conventional proportional Integral (PI) controller and a fuzzy logic (FL), controllers were used to control the same hybrid power system for the performance comparison. Simulations of the proposed Adaptive gain scheduling Fuzzy logic PID controller in an isolated wind diesel micro hydro hybrid power system with different load disturbances and with wind disturbances are performed. The proposed Adaptive gain scheduling Fuzzy logic PID controller provides best control performance over a wide range of operating conditions. The performance of the proposed approach is verified from simulations and comparisons. Simulation results explicitly show that the performance of the proposed Adaptive gain scheduling Fuzzy logic PID controller is superior to the conventional PI controller and fuzzy logic controller against various load changes and variations of wind inputs. 
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Load Frequency Control, Wind Diesel Micro Hydro Hybrid System, Adaptive Gain Scheduling Fuzzy Logic PID Controller, Proportional Integral Controller, Fuzzy Logic Controller.



go to top   Modelling, Simulation and Analysis of a 5-dof Planar Parallelogram–link Biped Mechanism
         by Carla Campos, Ricardo Campa, Miguel Llama, Alfonso Pámanes

         Vol. 4. n. 6, pp. 3337-3352


Abstract - This paper reports the modelling, trajectory planning and control of a 5-degree-of-freedom biped robot with parallelogram-type links that is being designed and built in the Instituto Tecnológico de la Laguna, Mexico. The kinematic and dynamic models are obtained by using a simplified approach of the real mechanism. The model-based controller for the tracking of the proposed gait patterns, and the analysis of the Zero Moment Point, which determines the dynamic stability, are also presented. Simulation results give important information for the practical implementation of the mechanism.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Biped Robot, Kinematics, Dynamics, Computed-Torque Control, Zero-Moment Point.


go to top   Computation of Electric Field and Potential Distribution around a Polluted Porcelain Insulator by Boundary Element Method
         by K.Krishnamoorthi, S.Chandrasekar, D.Pradhap

         Vol. 4. n. 6, pp. 3353-3360


Abstract - This paper presents the simulation results of electric field and potential distributions along surface of porcelain insulator by two –dimensional boundary element method(BEM).In this work, 2D Electrostatic software based simulation was carried out on 11 KV porcelain insulator at different conditions. Clean and various contamination conditions with and without water droplets. The simulation results show that contaminations have no effect on potential distribution along the insulator surface while electric field distributions are obviously on contamination conditions.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Electric Field Distribution, Potential Distribution, Porcelain Insulator, Boundary Element Method.



go to top   Fuzzy Pattern Recognition Based Fault Diagnosis
         by Rafik Bensaadi, Leïla H. Mouss, Mohamed D. Mouss, Mohamed Benbouzid

         Vol. 4. n. 6, pp. 3361-3370


Abstract - In order to avoid catastrophic situations when the dynamics of a physical system (entity in Multi Agent System architecture) are evolving toward an undesirable operating mode, particular and quick safety actions have to be programmed in the control design. Classic control (PID and even state model based methods) becomes powerless for complex plants (nonlinear, MIMO and ill-defined systems). A more efficient diagnosis requires an artificial intelligence approach. We propose in this paper the design of a Fuzzy Pattern Recognition System (FPRS) that solves, in real time, the main following problems: 1) Identification of an actual state; 2) Identification of an eventual evolution towards a failure state; 3) Diagnosis and decision-making. Simulations have been carried for a fictive complex process plant with the objective to evaluate the consistency and the performance of the proposed diagnosis philosophy. The obtained results seem to be encouraging and very promising for application to fault diagnosis of a real and complex plant process.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Diagnosis, Fault Detection, Pattern Recognition, Fuzzy Control, Conjugate Gradients, Complex Plant Process.



go to top   Smart Assisting Device for Partially Paralyzed People during Locomotion-Design and Control
         by  T.S.Sirish, K.S.Sivanandan

         Vol. 4. n. 6, pp. 3371-3375


Abstract - In the present living conditions people with disabilities (lower limb weakness) are increasing day by day. In order to assist the simple daily activities of those people an assistive device is designed. The device developed is used to support the user to perform the normal walking without the use of his hands (crutches), so that he can do other activities during walking with hands. The device will support the user during the stance and swing phase of gait by locking the knee during stance phase and unlocking during swing phase. Stepper motors are used to lock and unlock the knee automatically during human locomotion. A driving circuit is designed using PIC to synchronize the activities. A feed back technique is used to make the operation automatic.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Assistive Device, Gait Posture, Human Locomotion.



go to top   Wind-PV-Grid Connected Hybrid Renewable System in Kish Island
         by Arash Anzalchi, Babak Mozafari

         Vol. 4. n. 6, pp. 3376-3382


Abstract - This study presents an analysis of the technical and financial viability of grid/RES hybrid power supply configurations for a touristy Island. Assessment criteria comprised net present cost (NPC), cost of energy (COE) and green house gases (GHG) reduction. The RES software HOMER (National Renewable Energy Laboratory, US) was utilized as the assessment tool with modeling performed with hourly load data input from Kish Island in tropical area of Hormozgan, Iran. As Kish is not connected to grid, price of a submarine transmission system is entered as the fixed capital cost of the system. Grid connection is required as energy backup and as well to make the system commercial. If the electricity produced by the renewable energy sources was not enough to supply the Kish's demand, the required energy would be supplied by purchasing energy from the grid. Otherwise, if the energy produced by RES excesses the load of Kish Island, the excess energy would be sold to the grid.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  PV Panel, Wind Turbine, Renewable Energy, Cost of Energy.



go to top   Coupled-Mode Analysis of a T-branch Waveguide with a Wavelength-Selective Reflection Feedback
         by K. Fasihi

         Vol. 4. n. 6, pp. 3383-3387


Abstract - The operation of T-branch waveguides with a wavelength-selective reflection feedback is analyzed using theoretical and numerical analysis. The coupled-mode theory (CMT) is employed to drive the necessary conditions for achieving perfect transmission. The analytic results reveal that the reflection to the input port is absent when the phase-shift of the electromagnetic waves traveling between the cavities is equal to (2n+1) π/2 and the decay rates into the three ports are equal. The finite-difference time-domain (FDTD) simulation results of the modified T-branch which is implemented in two dimensional photonic crystals (2D-PC), show that the analysis is valid. The proposed structure might also be valuable for design of other integrated optical functions.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Coupled-Mode Theory (CMT), Finite-Difference Time-Domain (FDTD), T-Branch Waveguide, Photonic Crystal (PC), Attenuator, Wavelength-Selective Reflector.



go to top   Prediction of Module Operating Temperatures for Free-Standing (FS) Photovoltaic (PV) System in Malaysia
         by H. Zainuddin, S. Shaari, A.M. Omar, S.I. Sulaiman, Z. Mahmud, F.Muhamad Darus

         Vol. 4. n. 6, pp. 3388-3394


Abstract - Numerous thermal models have been developed to predict the photovoltaic (PV) module operating temperature (Tm) mainly in the high latitude regions. Only a few has been developed in tropical region, specifically Malaysia. However, none of these studies have quantified the effect of humidity in predicting Tm despite the other widely used ambient variables. Therefore, in this study a new multiple linear regression (MLR) Tm model (HZ1) with four ambient variables; namely plane-of-array irradiance, ambient temperature, wind speed and relative humidity is proposed. The accuracy, validity and suitability were analyzed and compared with Sandia National Laboratory (SNL) model and Nominal Operating Cell Temperature (NOCT) model for free-standing (FS) PV system in Malaysia. Mean absolute percentage error (MAPE) and root mean square error (RMSE) were used as error measures and R2 was determined as coefficient of determination of the three aforementioned models for comparison. As a conclusion, the new proposed model (HZ1) is more accurate than SNL and NOCT models in predicting PV module operating temperature for FS PV system in Malaysia.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Module Operating Temperature, Free-Standing, HZ1 Model, SNL Model, NOCT Model.



go to top   A Study on Duffing Oscillator’s Ability on Detecting Disappearance of the Detected Weak Signal
         by V. Rashtchi, M. Nourazar

         Vol. 4. n. 6, pp. 3395-3401


Abstract - After the successful use of duffing oscillator in weak signal detection, many researches are done on this subject. Most of these studies only analyze the efficiency of duffing oscillator on detecting the existence of weak signal and they ignore to study duffing oscillator’s ability on detecting the loss of signal that was already detected. Considering this, we are going to analyze this ignored issue. In this paper we introduce two methods to add this ability to duffing oscillator.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Weak Signal Detection, Duffing Oscillator, Largest Lyapunov Exponent, Oscillator Resetting.



go to top   Performance Comparison of Dynamic Models of Proton Exchange Membrane and Planar Solid Oxide Fuel Cells Subjected to Load Change
         by N. A. Zambri, A. Mohamed, H. Shareef

         Vol. 4. n. 6, pp. 3402-3409


Abstract - The depletion of fossil fuel, rise in oil prices, increase in power demand and environmental concerns has led renewable energy to be an alternative energy option. Among the various types of renewable energy, fuel cell technology shows a great potential in electrical energy sector due to several reasons such as high efficiency, clean operation, and immune to weather conditions. Fuel cell is an electrochemical device that converts chemical energy of a reaction directly into electrical energy and can be categorized as a high grade electricity source because of its ability to produce constant power at full load. This paper presents mathematical modeling and simulation study of proton exchange membrane and planar solid oxide fuel cells by using Matlab/Simulink software. The main objective of this paper is to compare the simulation results of the two fuel cell types which stated earlier. Simulation results show that proton exchange membrane fuel cell has higher voltage capacity and power density while planar solid oxide fuel cell gives better performance for the step load current changes.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Proton Exchange Membrane Fuel Cell, Planar Solid Oxide Fuel Cell, Dynamic Model.



go to top   Design and Analysis of a Composite Cone Type Spacer in Gas Insulated Systems under Various Abnormal Conditions Using Finite Element Method
         by D.Deepak Chowdary, J.Amarnath

         Vol. 4. n. 6, pp. 3410-3417


Abstract - – Interfaces formed by gas dielectric and solid insulating spacer represent the weakest point in Gas Insulated Systems (GIS). It is essential to determine the electric field distribution along the spacer surfaces and evaluate the degree of their reliability. A key aspect in the design and optimization process of insulating spacers is the precise simulation and geometric optimization of the electric field distribution on the dielectrics. The breakdown strength of GIS is strongly influenced by the roughness of the spacer's surface like protrusions and depressions and defects produced from improper manufacturing. One of these forms is the loss of adhesion at electrode/epoxy interface which leads to initiating delamination. Bulk dielectric failure of spacers can be attributed to delamination at the electrode/epoxy interface. Electric field distribution at the protrusions, dispersions on the surface of the spacer, delamination and voids plays a critical factor affecting the breakdown of spacer. Field emission from the cathode triple junction is the primary initiating mechanism of surface flashover of insulators. In this work, the electric field distribution on the surface of the insulator is studied at the cathode end triple junction for a cone type spacer with and without metal insert along with the effect of protrusion, depression, delamination and void. The Finite Element Method, an efficient technique for solving field problems, is employed to compute the electric field.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords: Gas Insulated Systems, Electric Field Distribution, Finite Element Method.



go to top   Air Traffic Flow Modelling and Simulations Based on Dynamic Networks
         by K. Bousson, Tiago M. Domingues

         Vol. 4. n. 6, pp. 3418-3424


Abstract - Congestion in the Terminal Maneuvering Areas (TMAs) of larger airports impacts all aspects of air traffic flow not only at national level but may also induce arrival delays at international level. Hence, there is a need to forecast the air traffic flow density in TMAs so that appropriate decisions may be taken to optimize their occupancy rates. The approach taken in the present paper relies on dynamic network concepts for air traffic flow modelling and simulation. Indeed, the focus has been on the predictive estimation of the number of aircraft in specified TMAs across-time. The simulation of the described models has been performed to validate successfully the air traffic flow dynamics from actual and realistic data of a network of three TMAs in the Iberian Peninsula. The modeling concepts in the present research work may help stakeholders for TMA capacity management and optimization and subsequent airport socio-economic policies.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Air Traffic Flow, Modelling and Simulation, Terminal Maneuvering Area (TMA), Predictive Estimation.



go to top   Performance Enhancement in Rolling Processes Using Mixed Sensor-based and Estimation-based Control Algorithms
         by Shahab Amelian, Hamid Reza Koofigar

         Vol. 4. n. 6, pp. 3425-3429


Abstract - This paper presents a novel approach for improving the performance of rolling mills, by designing an estimation-based control algorithm. This is motivated by the fact that using several kinds of sensors for measuring all of process variables is technically and economically avoided. On the other hand, high quality may be obtained by some control algorithms at the expense of using many sensors for exact measurement. Therefore, there is a trade-off between high quality and technical limitations which should be managed in such a manner that the best result is achieved. The proposed algorithm satisfies both objectives including high quality and low production costs by developing reduced order state observers. The designed estimation-based control technique facilitates combining sensor-based and sensorless design methodologies. This technique is applicable to both hot rolling and cold rolling processes. A typical cold rolling process is adopted here to evaluate the effectiveness of the proposed estimation method. Simulation results show that the desired performance can be achieved using the developed strategy.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Reduced Order Observer, Instrumentation, Mathematical Model, Rolling Mill.



go to top   Coordination of Overcurrent Relays Using New Two Step Algorithms, a Comparative Study Versus Classic Optimization Algorithms
         by Hadi. Hosseinian Yengejeh, Hossein. Nasir Aghdam, Hossein. Askarian Abyaneh

         Vol. 4. n. 6, pp. 3430-3441


Abstract - In this paper in order to determine the abilities and limitations of each random search algorithm for solving overcurrent (O/C) relay coordination problem, a comprehensive comparison is made. The algorithms which are chosen for the comparison are; Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Immune Genetic Algorithm (IGA) and some two two step mentioned algorithms. The convergence speed and convergence reliability have been compared. Variation of convergence speed and the number of points that each algorithm explore to reach global optimum point have been also investigated. To consider equal condition, all of the algorithms programs have been run in same computer (Pentium III 3.0 GHz). Important and effective parameters of algorithms such as population size and initial populations range in the algorithms have been assumed identical. The algorithms abilities have been tested on two case studies, namely the 8 bus distribution network and 8 buss transmission systems. It will be shown that solving the coordination problem using some of the two step methods such as IGA–GA can be faster than the others. From reliability of convergence viewpoint PSO have had best performance. Success of other algorithms in this problem solving, from various aspects have been ranked.
Copyright © 2011 Praise Worthy Prize S.r.l. - All rights reserved


Keywords:  Coordination, Intelligent Methods, Overcurrent Relays.





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