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Home>Products>Journal and Reviews>I.R.E.E.>Latest issue
International Review of Electrical Engineering - June 2008 - Papers
International Review of Electrical Engineering - Papers
by S. M. Ayob, N. A. Azli, Z. Salam Vol. 3. n. 3, pp. 418-425
Abstract - This paper proposed the design and implementation of the Single Input PI-Fuzzy Controller (SIPI-FC) for single phase inverter system. The proposed SIPI-FC offers several advantages compared to its conventional PI-FC, namely simpler control structure, less tuning parameters and fewer number of rules- which in turn leads to less tuning complexity. To realize the SIPI-FC, a low power single phase inverter hardware prototype is constructed. A digital signal processor system from dSPACE is used to implement the controller algorithm. The performance of the proposed SIPI-FC is then compared with the discrete linear PI controller and the conventional PI-FC. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Fuzzy control, Inverter, Pulse Width Modulatio.
Vol. 3. n. 3, pp. 426-434
Abstract - In this paper, a novel control scheme based on the field programmable gate array (FPGA) is proposed herein, which is utilized to improve the upload response for the zero-voltage-switching (ZVS) buck converter. Without changing controller parameters and system topology and only with modifying pulse-width-modulation (PWM) control signals, the upload response can be upgraded. In order to verify the proposed control scheme, there are some simulation and experimental results provided in addition to detailed description of the corresponding basic operating principles. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: ZVS buck converter, upload response.
Vol. 3. n. 3, pp. 435-443
Abstract - This paper investigates control methods for the 3 level unified power flow controller in order to improve the stability of a power system hence providing security under increased power flow conditions. These include a direct PI controller with decoupling (PI), Adaptive state feedback based on multivariable Elman neural network (MIMO-NSF) and multivariable GPC with decoupling algorithm (MIMO-GPC). The performances of these controllers are evaluated under different operating conditions of the power system. The results demonstrate that MIMO NSF and multivariable GPC are very effective in improving the transient power system stability and very robust against variable transmission line parameters. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: 3 level UPFC, NSF controller, MIMO GPC, power system oscillations.
Vol. 3. n. 3, pp. 444-454
Abstract - Four-wire shunt active power filters have been intensively studied since the early 90’s. Even though four-wire active power filter topologies are typically based on voltage source technology, some attention has also been paid to current source topologies. This paper presents a filtering performance and efficiency study of four-wire shunt active power filters. The study includes two common voltage source topologies and a current source topology with two different dc-link structures. The filtering performance, power loss distribution and efficiencies of the topologies are examined and compared on the basis of experimental tests. The results show that the best filtering performance and efficiency can be achieved with the four-wire voltage source topologies. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Four-Wire System, Harmonics, Neutral Current, Power Loss, Power Quality.
Vol. 3. n. 3, pp. 455-465
Abstract - In traction application, the electric motor design methodology is not trivial. This paper presents various design approaches using rated point or load cycle. Design optimizations of surface-mounted permanent magnet traction motor are carried out using these approaches. Therefore, a comparative study is done through optimal motors obtained from optimization techniques. This paper shows advantages and drawbacks of each approach in traction motor design. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: design methodology, powertrain, optimization, permanent magnet motor.
Vol. 3. n. 3, pp. 466-478
Abstract - The strategies of energy sources control and management strongly affect the lifetime of power supply system, the performance and the global efficiency of hybrid vehicles. On-roll and on-road tests are not always possible to thoroughly test each subsystem. Therefore, a test bench of hybrid electric vehicles is developed, which can be used to evaluate and optimize each subsystem of hybrid propulsion system in earlier phase. In this paper, the strategies of energy source control and management are first defined and verified. Based on these strategies, the power flow and energy consumption of a hybrid propulsion system in NEDC and FTP cycles are estimated; and the super capacitor energy storage is tested in this platform with real-time simulation system. Further, the hybrid propulsion system of a light vehicle is emulated (in hardware) in this test platform and tested in ECE15 cycle. Both test results prove that the presented strategies of energy sources control and management can ensure good operating condition of the power supply system (e.g. battery, fuel cell) and undertaking peak power demand of traction system. As a result, long life time of power supply system, high efficiency and good performance of vehicles can be achieved. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Super capacitor, Hybrid Electric Vehicle, Regenerative braking, Real-time simulation, Energy sources control and management.
Vol. 3. n. 3, pp. 479-483
Abstract - This paper presents an analysis of transient behavior of grounding electrode under the soil ionization effect. The proposed numerical model offers the new approach to the transmission line modeling of a grounding system. The numerical model is based on the finite element method (FEM) applied to the transmission line equations in the time domain. The effect of the soil ionization on the dynamic resistance has been taken into account by dynamic change of the radius of the grounding conductor. Besides the soil ionization effect it will be shown the effect of soil permitivity to the dynamic resistance. The obtained results have been compared to the available experimental results from the literature. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: The finite element method, nonlinear transmission line, electromagnetic transients.
Vol. 3. n. 3, pp. 484-490
Abstract - During the insulation testing of an electrical supply network having isolated neutral, the capacitive component does not allow us to know the state of the cable insulation. On the other hand it is the testing of the active component that helps in the electrical danger elimination in case there is an insulation failure. The current leak being a function of the active and capacitive component that could cause the disconnection of the electrical network even in the absence of faults. A compensation of the network capacitive effect gives the possibility to measure the resistive current leak. The experimental electrical circuits built allowed us to define the whole combinations between the leakage resistance (single-phase, double-phase and three-phase) and the different levels of insulation of the network with respect to earth. The obtained results give an insight into the domains sensitivity of the protection circuits of the insulation active component while keeping the leakage current at safe value of 10 mA. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Electrical insulation. Leak current. Leak resistance. Harmless current. Protecton devices.
Vol. 3. n. 3, pp. 491-497
Abstract - This paper presents a procedure for dispatching reactive power and voltage control problem in the electrical power transmission system. The proposed approach is based on the load flow, control voltage and optimization. The load flow is realised by the Newton-Raphson method in polar form. A control strategy has been obtained, in the case of voltage violation by heuristic technique. The optimization is achieved on the non-linear programming while considering the reactive power of generators as a control variable. Finally, the up-to-date results obtained are analysed according to the validity of the proposed procedure and believed to be satisfactory. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Load flow, Heuristic, Rules, var optimization.
Vol. 3. n. 3, pp. 498-512
Abstract - The most challenging issue in terms of microgrid stability is the transfer from normal parallel operation to islanded operation. The stability after transition to island operation due to a fault in the utility grid depends mainly on the depth and duration of the voltage dip caused by the fault. Particularly sensitive to voltage dips before islanding are directly and through frequency converter connected rotating machines. During transition to island operation fault ride-through capability is also required from these machines. In this paper the stability of the microgrid after fault in the utility grid is studied with different configurations and multiple simulations, which are made with PSCAD simulation software. This paper presents alternative options to maintain the stability of an islanded microgrid by reduction of voltage dip duration or magnitude. On the other hand, the stability effect and the fault ride-through improvement of the converter based distributed generation units with different phase-locked loop component modifications are studied by simulations. Finally summary of the possibilities to ensure stability of the microgrid after islanding due to fault in the utility grid is presented. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Microgrid, Stability, Distributed Generation, Energy Storage, Voltage Dip Compensation, Low Voltage Network.
by T. Niknam, M. Nayeripour, J. Olamaei, A. Arefi Vol. 3. n. 3, pp. 513-524
Abstract - This paper presents a new hybrid evolutionary algorithm based on Particle Swarm Optimization (PSO) and Ant Colony Optimization (ACO) for daily Volt/Var control in distribution system including Distributed Generators (DGs). Due to the small X/R ratio and radial configuration of distribution systems, DGs have much impact on this problem. Since DGs are independent power producers or private ownership, a price based methodology is proposed as a proper signal to encourage owners of DGs in active power generation. Generally, the daily Volt/Var control is a nonlinear optimization problem. Therefore, an efficient hybrid evolutionary method based on Particle Swarm Optimization and Ant Colony Optimization (ACO), called HPSO, is proposed to determine the active power values of DGs, reactive power values of capacitors and tap positions of transformers for the next day. The feasibility of the proposed algorithm is demonstrated and compared with methods based on the original PSO, ACO and GA algorithms on IEEE 34-bus distribution feeder. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Ant Colony Optimization (ACO), Distributed Generators, Particle Swarm Optimization (PSO) Voltage and Reactive Power Control.
by J. Viswanatha Rao, S. Sivanagaraju Vol. 3. n. 3, pp. 525-531
Abstract - This paper presents selection of optimal locations and sizes for voltage regulators in radial distribution system. The operation and planning studies of a distribution system require a steady state condition of the system for various load demands. Voltage has always been considered as an integral part of the power system response. There are several factors, which contribute to voltage collapse such as increased loading on distribution feeders, reactive power constraints, on load tap charger dynamics and load characteristics. The proposed method using particle swarm optimization control for voltage regulator placement is suitable for large radial distribution network. The aim of this paper is to obtain optimal voltage control with voltage regulators and then to decrease the total cost and losses, to obtain the maximum net savings. An algorithm makes the initial selection, installation and tap setting of the voltage regulators to provide a smooth voltage profile along the network. The effectiveness of the proposed method is illustrated with 33 bus and 69 bus radial distribution systems. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Discrete Particle Swarm Optimization, Radial Distribution Systems, Voltage Regulators.
Vol. 3. n. 3, pp. 532-542
Abstract - This paper presents a multi-class Support Vector Machine (SVM) based method for on-line static security assessment of power systems. To classify the system security status, a group of binary SVMs have been trained. One of the main points, to apply machine learning method is feature selection. In this paper, a new Decision Tree (DT) based feature selection algorithm has been presented. The SVM decision boundary is determined by a small subset of training data, called Support Vectors (SVs). Therefore, it is desirable, to select only SVs, to reduce the problem size and consequently to reduce the training time. Data for SVM training has been selected based on a new modified algorithm. The proposed method has been applied to New England 39-bus power system. The simulation results demonstrate the effectiveness and the stability of the proposed method for on-line static security assessment procedure of large scale power system. Also, the effectiveness of the proposed feature selection and the data selection algorithms have been investigated, too. It has been shown that the proposed algorithms can reduce the SVM training set size and maintain the generalization performance of the resulting multi-class SVM. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Machine learning, Multi-Class Support Vector Machines (SVM), Feature Selection, Power System Security.
Vol. 3. n. 3, pp. 543-550
Abstract - This paper presents a novel scheme to allocate active power losses to the various consumers in an unbalanced radial distribution system. An active power loss allocation formula for a balanced radial distribution system is first developed and the loss allocation scheme is then proposed based on this formula. The scheme is then extended to allocate loss for an unbalanced radial distribution system. The proposed loss allocation method utilizes the load flow results of the multiphase unbalanced radial distribution system to allocate the active power losses to the various consumers of the system connected at the different buses. To obtain the load flow results, the forward and backward sweep method has been used in which the system loads are modeled as composite loads. The feeder power losses for various phases are calculated first from the load flow. Using the loss allocation formula developed earlier, the real power losses are allocated to the various consumers. The loss allocation scheme has been successfully implemented with the three practical test distribution systems, where consumer loads are modeled both as constant power and composite type. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Radial Distribution Network (RDN), Active Power Loss Allocation, Composite loads.
Vol. 3. n. 3, pp. 551-557
Abstract - Most of world’s electric power systems are now widely interconnected involving inter-regional and international connections. The purpose is to achieve better efficiency in generation and transport of energy. We need these interconnections to take advantage of diversity of loads, availability of sources and fuel price to supply electricity at minimum cost with a required reliability. In addition to the existing interconnections, namely those of the Maghreb, Algeria is Already interconnected to Tunisia (4 connections) and to Morocco (2 connections). Recent connections were brought into service, including those linking Spain to Morocco, Libya to Egypt, Egypt to Jordan, and Syria to Jordan and Lebanon. But a direct interconnection with European countries around Mediterranean Sea will be open up news opportunities to both partners for economic and technical reasons. Since 2002, Algeria has a new politic to diversify international exchanges. A study of Interconnection Spanish-Algerian network project has been done by Red Electrica and Sonelgaz for its realisation. In this article, we propose the application of the new ABB Technology of HVDC Light to achieve this interconnection. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: HVDC light, power systems interconnection.
Vol. 3. n. 3, pp. 558-565
Abstract - Software Defined Radio (SDR) has been used by many military and commercial communication applications. The need to identify the digital modulation type of an incoming radio signal is important in order to design an intelligent system that can be used for different applications. This paper describes an comparison approach to identify various digital modulated signals by using either wavelet transform to extract the transient characteristics of the digital modulated signal, or fast Fourier transform (FFT) to measure the power level at different frequencies, allowing a simple identification process. The detail methods to identify the modulation scheme of signals by the wavelet transform and FFT is described. The performance of the identification is investigated through simulation for different signal to noise ratio (SNR) values. Result showed that the system identification performance is improved more than 95% when SNR is more than 9dB for the entire proposed schemes using both wavelet transform technique and FFT. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: SDR, wavelet transform and Fast Fourier transform.
Vol. 3. n. 3, pp. 566-572
Abstract - This paper summarizes the results obtained during experiments with evolutionary algorithms in synthesis of passive LC filters. The aim of the presented experiments was to verify the heuristic algorithms’ ability to successfully solve filter design problems and to address various optimization requirements. A design of lossless and lossy low-pass filters is discussed; attention is further devoted to the optimized design of narrow band-pass filters. The algorithms used were implemented in mathematical program MAPLE. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Passive LC filters, Filter design, Optimization, Differential Evolutionary Algorithms.
Vol. 3. n. 3, pp. 573-579
Abstract - Several technological parameters of the rolls resulted in aluminum processing industry must be measured and displayed, with imposed precision, during the rewinding process. These parameters are the length and mass of the rewound foil, and the outside diameter of the roll. An intelligent measuring system that needs only the assignment of the foil width and thickness before each measuring process of the afore-mentioned parameters is presented in this paper. The structure of our intelligent system consists of two rotary incremental encoders, an interface with 80C552 microcontroller and an IBM-PC compatible computer. Its experimental model was tested and some results are presented and discussed. Such intelligent measuring system is very useful not only in industrial applications but in higher education and research activities. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Computer, Intelligent Interface, Measuring System, Technological Parameters.
Vol. 3. n. 3, pp. 580-591
Abstract - This paper proposes a powerful methodology wavelet networks to investigate the effects of international F/X markets on emerging markets currencies. We used EUR/USD parity as input indicator (international F/X markets) and three emerging markets currencies as output indicator (emerging markets currency). We test if the effects of international F/X markets change across different timescale. Using wavelet networks, it is found that the effects of international F/X markets increase with higher timescale. This evidence shows that the causality of international F/X markets on emerging markets should be tested based on 32-64 days effect. We also find that the effects of EUR/USD parity on Turkish Lira is higher on 9-16 days and 33-64 days scales and this evidence shows that Turkish lira is less stable compare to other emerging markets currencies as international F/X markets effects Turkish lira on shorten time scale. Besides it is found that Russian ruble is mostly affected from international F/X market in the long time according to wavelet networks analysis. Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Signal processing, Wavelet networks, Neural networks, FX markets.
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