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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Electrical Engineering and Technology
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Journal DOI :
The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 5, Issue 4 - Nov 2010
Volume 5, Issue 3 - Sep 2010
Volume 5, Issue 2 - Jun 2010
Volume 5, Issue 1 - Mar 2010
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Optimal Location of FACTS Devices Using Adaptive Particle Swarm Optimization Hybrid with Simulated Annealing
Ajami, Ali ; Aghajani, Gh. ; Pourmahmood, M. ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 179~190
DOI : 10.5370/JEET.2010.5.2.179
This paper describes a new stochastic heuristic algorithm in engineering problem optimization especially in power system applications. An improved particle swarm optimization (PSO) called adaptive particle swarm optimization (APSO), mixed with simulated annealing (SA), is introduced and referred to as APSO-SA. This algorithm uses a novel PSO algorithm (APSO) to increase the convergence rate and incorporate the ability of SA to avoid being trapped in a local optimum. The APSO-SA algorithm efficiency is verified using some benchmark functions. This paper presents the application of APSO-SA to find the optimal location, type and size of flexible AC transmission system devices. Two types of FACTS devices, the thyristor controlled series capacitor (TCSC) and the static VAR compensator (SVC), are considered. The main objectives of the presented method are increasing the voltage stability index and over load factor, decreasing the cost of investment and total real power losses in the power system. In this regard, two cases are considered: single-type devices (same type of FACTS devices) and multi-type devices (combination of TCSC, SVC). Using the proposed method, the locations, type and sizes of FACTS devices are obtained to reach the optimal objective function. The APSO-SA is used to solve the above non.linear programming optimization problem for better accuracy and fast convergence and its results are compared with results of conventional PSO. The presented method expands the search space, improves performance and accelerates to the speed convergence, in comparison with the conventional PSO algorithm. The optimization results are compared with the standard PSO method. This comparison confirms the efficiency and validity of the proposed method. The proposed approach is examined and tested on IEEE 14 bus systems by MATLAB software. Numerical results demonstrate that the APSO-SA is fast and has a much lower computational cost.
Primary Restorative Transmission Line Selection for Myanmar's Electric Power System
Kim, Yong-Hak ; Song, In-Jun ; Jang, Byung-Tae ; An, Yong-Ho ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 191~196
DOI : 10.5370/JEET.2010.5.2.191
Power system restoration following a massive or complete blackout starts with energizing the primary restorative transmission system. During this primary restoration process, unexpected overvoltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. In the case of the Myanmar electric power system, there are so many wide outage experiences, including complete blackout cases, caused by 230kV line faults and so on. Consequently, Myanmar's system operators have been well trained to deal with wide blackouts. Howver, system blackout restoration has been conducted by relying on the experience of only a few specialists. So, more scientific analysis is required to meet the requirements necessary to ensure fast and reliable system restoration. This paper presents analytical results on the primary restorative transmission system of Myanmar, focusing on the problems during the early restoration process. Methodologies are presented that handle load pick-up, terminal voltage and the reactive capability limitation of black-start generators to compensate the Ferranti effect. Static and dynamic simulation with the PSSolution and EMTDC programs respectively for the six cases are performed in order to select the primary restorative transmission lines.
An Adaptive UPFC Based S tabilizer forDamping of Low Frequency Oscillation
Banaei, M.R. ; Hashemi, A. ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 197~208
DOI : 10.5370/JEET.2010.5.2.197
Unified power flow controller (UPFC) is the most reliable device in the FACTS concept. It has the ability to adjust all three control parameters effective in power flow and voltage stability. In this paper, a linearized model of a power system installed with a UPFC has been presented. UPFC has four control loops that by adding an extra signal to one of them, increases dynamic stability and load angle oscillations are damped. In this paper, after open loop eigenvalue (electro mechanical mode) calculations, state-space equations have been used to design damping controller and it has been considered to influence active and reactive power flow durations as the input of damping controller, in addition to the common speed duration of synchronous generators as input damper signal. To increase stability, further Lead-Lag and LQR controllers, a novel on-line adaptive controller has been used analytically to identify power system parameters. Closed-loop calculations of the electro mechanical mode verify the improvement of system pole placement after controller designing. Suitable operation of adaptive controller to decrease rotor speed oscillations against input mechanical torque disturbances is confirmed by the simulation results.
Dynamic ATC Computation for Real-Time Power Markets
Venkaiah, Ch. ; Kumar, D.M. Vinod ; Murali, K. ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 209~219
DOI : 10.5370/JEET.2010.5.2.209
In this paper, a novel dynamic available transfer capability (DATC) has been computed for real time applications using three different intelligent techniques viz. i) back propagation algorithm (BPA), ii) radial basis function (RBF), and iii) adaptive neuro fuzzy inference system (ANFIS) for the first time. The conventional method of DATC is tedious and time consuming. DATC is concerned with calculating the maximum increase in point to point transfer such that the transient response remains stable and viable. The ATC information is to be continuously updated in real time and made available to market participants through an internet based Open Access Same time Information System (OASIS). The independent system operator (ISO) evaluates the transaction in real time on the basis of DATC information. The dynamic contingency screening method  has been utilized and critical contingencies are selected for the computation of DATC using the energy function based potential energy boundary surface (PEBS) method. The PEBS based DATC has been utilized to generate patterns for the intelligent techniques. The three different intelligent methods are tested on New England 68-bus 16 machine and 39-bus 10 machine systems and results are compared with the conventional PEBS method.
A Novel Fault Location Scheme on Korean Electric Railway System Using the 9-Conductor Representation
Lee, Chang-Mu ; Lee, Han-Sang ; Yoon, Dong-Hee ; Lee, Han-Min ; Song, Ji-Young ; Jang, Gil-Soo ; Han, Byung-Moon ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 220~227
DOI : 10.5370/JEET.2010.5.2.220
This paper presents a novel fault location scheme on Korean AC electric railway systems. On AC railway system, because of long distance, 40[km] or above, between two railway substations, a fault location technique is very important. Since the fault current flows through the catenary system, it must be modeled exactly to analyze the fault current magnitude and fault location. In this paper, suggesting the novel scheme of fault location, a 9-conductor modeling technique including boost wires and impedance bonds is introduced based on the characteristics of Korean AC electric railway. After obtaining a 9-conductor modeling, the railway system is constructed for computer simulation by using PSCAD/EMTDC. By case studies, we can verify superiority of a new fault location scheme and propose a powerful model for fault analysis on electric railway systems.
Energy Storage Application Strategy on DC Electric Railroad System using a Novel Railroad Analysis Algorithm
Lee, Han-Sang ; Lee, Han-Min ; Lee, Chang-Mu ; Jang, Gil-Soo ; Kim, Gil-Dong ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 228~238
DOI : 10.5370/JEET.2010.5.2.228
There is an increasing interest in research to help overcome the energy crisis that has been focused on energy storage applications in various parts of power systems. Energy storage systems are good at enhancing the reliability or improving the efficiency of a power system by creating a time gap between the generation and the consumption of power. As a contribution to the various applications of storage devices, this paper describes a novel algorithm that determines the power and storage capacity of selected energy storage devices in order to improve upon railroad system efficiency. The algorithm is also demonstrated by means of simulation studies for the Korean railroad lines now in service. A part of this novel algorithm includes the DC railroad powerflow algorithm that considers the mobility of railroad vehicles, which is necessary because the electric railroad system has a distinct distribution system where the location and power of vehicles are not fixed values. In order to derive a more accurate powerflow result, this algorithm has been designed to consider the rail voltage as well as the feeder voltage for calculating the vehicle voltage. By applying the resultant control scheme, the charging or discharging within a specific voltage boundary, energy savings and a substation voltage stabilization using storage devices are achieved at the same time.
Optimal Transmission Expansion Planning Considering the Uncertainties of the Power Market
Bae, In-Su ; Son, Min-Kyun ; Kim, Jin-O ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 239~245
DOI : 10.5370/JEET.2010.5.2.239
Today, as power trades between generators and loads are liberalized, the uncertainty level of power systems is rapidly increasing. Therefore, transmission operators are required to incorporate these uncertainties when establishing an investment plan for effective operation of transmission facilities. This paper proposes the methodology for an optimal solution of transmission expansion plans for the long-term in a deregulated power system. The proposed model uses the probabilistic cost of transmission congestion for various scenarios and the annual increasing rates of loads. The locations and the installation times of expanded transmissions lines with minimum cost are acquired by the model. To minimize the investment risk, the Mean-Variance Markowitz portfolio theory is applied to the model. In a case study, the optimal solution of a transmission expansion plan is obtained considering the uncertain power market.
A Multiagent System for Microgrid Operation in the Grid-interconnected Mode
Kim, Hak-Man ; Kinoshita, Tetsuo ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 246~254
DOI : 10.5370/JEET.2010.5.2.246
This paper presents a multiagent system for microgrid operation in the grid-interconnected mode. An energy market environment with generation competition is adopted for microgrid operation in order to guarantee autonomous participation and meet the requirements of participants in the microgrid. The modified Contract Net Protocol (CNP) is used as a protocol for interactions among agents. The multiagent system for microgrid operation based on the modified CNP and the energy market environment is designed and implemented. To verify the feasibility of the suggested multiagent system, experiments on three operation conditions are carried out.
Estimation of Delta Winding Current and Its Application to a Compensated-Current-Differential Relay for a Y-Δ Transformer
Kang, Yong-Cheol ; Lee, Byung-Eun ; Jin, En-Shu ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 255~263
DOI : 10.5370/JEET.2010.5.2.255
The compensated-current-differential relay uses the same restraining current as a conventional relay, but the differential current is modified to compensate for the effects of the exciting current. Delta winding current is necessary to obtain the modified differential current for a
transformer. This paper describes an estimation algorithm of the delta winding current and its application to a compensated-current-differential relay for a
transformer. Prior to saturation, the core-loss current is calculated and used to modify the differential current. When the core first enters saturation, the initial value of the core flux is obtained by inserting the modified differential current into the magnetization curve. This flux value is used to derive the magnetizing current and consequently the modified differential current. The operating performance of the proposed relay was compared against a conventional current differential relay with harmonic blocking. Test results indicate that the proposed relay remained stable during severe magnetic inrush and over-excitation, and its operating time is significantly faster than a conventional relay. The relay is unaffected by the level of remanent flux and does not require an additional restraining or blocking signal to maintain stability. This paper concludes by implementing the proposed algorithm into a prototype relay based on a digital signal processor.
Analysis of Dielectric Breakdown of Hot SF
Gas in a Gas Circuit Breaker
Kim, Hong-Kyu ; Chong, Jin-Kyo ; Song, Ki-Dong ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 264~269
DOI : 10.5370/JEET.2010.5.2.264
This paper presents the analysis of the dielectric characteristics of a hot
gas in a gas circuit breaker. Hot gas flow is analyzed using the FVFLIC method considering the moving boundary, material properties of real
gas, and arc plasma. In the arc model, the re-absorption of the emitted radiation is approximated with the boundary source layer where the re-absorbed radiation energy is input as an energy source term in the energy conservation equation. The breakdown criterion of a hot gas is predicted using the critical electric field as a function of temperature and pressure. To validate the simulation method, breakdown voltage for a 145kV 40kA circuit breaker was measured for various conditions. Consistent results between the simulation and experiment were confirmed.
The Analysis of Liquid Metal Flow Characteristics in the Annular Passage of an Electromagnetic Pump
Kim, Chang-Eob ; Jeon, Mun-Ho ; Kwon, Jeong-Tae ; Lim, Hyo-Jae ; Lee, Suk-Won ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 270~275
DOI : 10.5370/JEET.2010.5.2.270
An electromagnetic pump using a tubular induction motor (TLIM) has been proposed to pump liquid metal fluids. TLIM has been designed for liquid metal flow systems with a motor with a thrust force of 40~77[N]. The flow characteristics have been investigated by solving the Navier-Stokes equation, where the Lorentz force was included simply by considering it as a constant in the Navier-Stokes equation. A wood metal was chosen to simulate the liquid metal. The effect of Lorentz force on the flow rate was investigated. An experiment was conducted and its results were compared with those of the simulation. The simulation result showed an overestimation of about 17% compared with the experimental one.
A New Fuzzy Logic based Modeling and Simulation of a Switched Reluctance Motor
Wadnerkar, Vikas S. ; Bhaskar, Mithun M. ; Das, Tulasi Ram ; RajKumar, A.D. ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 276~281
DOI : 10.5370/JEET.2010.5.2.276
The switched reluctance motor (SRM) is an older member of the electric machines family. Its simple structure, ruggedness and inexpensive manufacturing potential make it extremely attractive for industrial applications. However, these merits are overshadowed by its inherent high torque ripple, acoustic noise and difficulty to control. In this paper, a control strategy of the angle position control for the SRM drive based on fuzzy logic is illustrated. The input control parameter, the output control parameter and fuzzy control with FAM table formulation strategy are described and simulated with control patterns, and the decision form of the fuzzy control is illustrated and simulated, and the scope of implementing in a Fuzzy based ASIC chip is enlightened with literature support.
Analysis of Parameters Influence on the Characteristics of Thomson Coil Type Actuator of Arc Eliminator Using Adaptive Segmentation Equivalent Circuit Method
Li, Wei ; Jeong, Young-Woo ; Yoon, Hee-Sung ; Koh, Chang-Seop ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 282~289
DOI : 10.5370/JEET.2010.5.2.282
A Thomson coil type actuator is applied as the driving unit in an arc eliminator system. To eliminate the arc efficiently, the speed of the actuator is required as fast as possible with certain limit of the exciting current. Therefore, the dynamic characteristics of the Thomson coil type actuator should be analyzed in an effective way. In this paper, a novel solving technique has been developed based on the equivalent circuit model which is set up by dividing the conducting plate into multi segments. To guarantee the calculation accuracy and improve the calculation efficiency, an adaptive refinement algorithm is suggested based on the field continues condition. The proposed method has been verified by the FEM calculation and experiment. The influence of circuit and plate parameters to the performance of the actuator is also investigated, from which a reasonable set of parameters can be found.
Adaptive Carrier-based PWM for a Four-Switch Three-Phase Inverter under DC-link Voltage Ripple Conditions
Nguyen, Tuyen D. ; Lee, Hong-Hee ; Nguyen, Hoang M. ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 290~298
DOI : 10.5370/JEET.2010.5.2.290
This paper proposes an adaptive carrier-based pulse width modulation (PWM) method for a four-switch three-phase (4S3P) inverter under dc-link voltage ripple conditions. The proposed method guarantees balanced output currents despite of the existence of the voltage oscillations across two dc-link capacitors. And also, this new approach achieves a linear over-modulation with calculation time reduction. Simulation and experimental results are given to validate the feasibility of the proposed method.
DFIG Wind Power System with a DDPWM Controlled Matrix Converter
Lee, Ji-Heon ; Jeong, Jong-Kyou ; Han, Byung-Moon ; Choi, Nam-Sup ; Cha, Han-Ju ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 299~306
DOI : 10.5370/JEET.2010.5.2.299
This paper proposes a new doubly-fed induction generator (DFIG) system using a matrix converter controlled by direct duty ratio pulse-width modulation (DDPWM) scheme. DDPWM is a recently proposed carrier based modulation strategy for matrix converters which employs a triangular carrier and voltage references in a voltage source inverter. By using DDPWM, the matrix converter can directly and effectively generate rotor voltages following the voltage references within the closed control loop. The operation of the proposed DFIG system was verified through computer simulation and experimental works with a hardware simulator of a wind power turbine, which was built using a motor-generator set with vector drive. The simulation and experimental results confirm that a matrix converter with a DDPWM modulation scheme can be effectively applied for a DFIG wind power system.
Effect of Load Modeling on Low Frequency Current Ripple in Fuel Cell Generation Systems
Kim, Jong-Soo ; Choe, Gyu-Yeong ; Kang, Hyun-Soo ; Lee, Byoung-Kuk ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 307~318
DOI : 10.5370/JEET.2010.5.2.307
In this work, an accurate analysis of low frequency current ripple in residential fuel cell power generation systems is performed based on the proposed residential load model and its unique operation algorithm. Rather than using a constant dc voltage source, a proton exchange membrane fuel cell (PEMFC) model is implemented in this research so that a system-level analysis considering the fuel cell stack, power conditioning system (PCS), and the actual load is possible. Using the attained results, a comparative study regarding the discrepancies of low frequency current ripple between a simple resistor load and a realistic residential load is performed. The data indicate that the low frequency current ripple of the proposed residential load model is increased by more than a factor of two when compared to the low frequency current ripple of a simple resistor load under identical conditions. Theoretical analysis, simulation data, and experimental results are provided, along with a model of the load usage pattern of low frequency current ripples.
An Optimal Design Methodology of an Interleaved Boost Converter for Fuel Cell Applications
Choe, Gyu-Yeong ; Kim, Jong-Soo ; Kang, Hyun-Soo ; Lee, Byoung-Kuk ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 319~328
DOI : 10.5370/JEET.2010.5.2.319
In this paper, an optimal selection methodology for the number of phases will be proposed for an interleaved boost converter (IBC). Also, the analysis of the input current ripple according to CCM and DCM is carried out. The proposed design methodology will be theoretically analyzed, and its validity verified by simulation as well as with experimental results. Moreover, a comparison of cost and efficiency based on a 600W laboratory prototype using the Ballard NEXA 1.2kW PEMFC system is demonstrated.
Underwater Discharge Phenomena in Inhomogeneous Electric Fields Caused by Impulse Voltages
Lee, Bok-Hee ; Kim, Dong-Seong ; Choi, Jong-Hyuk ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 329~336
DOI : 10.5370/JEET.2010.5.2.329
The paper describes the electrical and optical properties of underwater discharges in highly inhomogeneous electric fields caused by 1.2/50
impulse voltages as functions of the polarity and amplitude of the applied voltage, and various water conductivities. The electric fields are formed by a point-to-plane electrode system. The formation of air bubbles is associated with a thermal process of the water located at the tip of the needle electrode, and streamer coronas can be initiated in the air bubbles and propagated through the test gap with stepped leaders. The fastest streamer channel experiences the final jump across the test gap. The negative streamer channels not only have more branches but are also more widely spread out than the positive streamer channels. The propagation velocity of the positive streamer is much faster than that of the negative one and, in fact, both these velocities are independent of the water conductivity; in addition the time-lag to breakdown is insensitive to water conductivity. The higher the water conductivity the larger the pre-breakdown energy, therefore, the ionic currents do not contribute to the initiation and propagation of the underwater discharges in the test conditions considered.
Piezo-electrically Actuated Micro Corner Cube Retroreflector (CCR) for Free-space Optical Communication Applications
Lee, Duk-Hyun ; Park, Jae-Y. ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 337~341
DOI : 10.5370/JEET.2010.5.2.337
In this paper, an extremely low voltage operated micro corner cube retroreflector (CCR) was fabricated for free-space optical communication applications by using bulk silicon micromachining technologies. The CCR was comprised of an orthogonal vertical mirror and a horizontal actuated mirror. For low voltage operation, the horizontal actuated mirror was designed with two PZT cantilever actuators, torsional bars, hinges, and a mirror plate with a size of
. In particular, the torsional bars and hinges were carefully simulated and designed to secure the flatness of the mirror plate by using a finite element method (FEM) simulator. The measured tilting angle was approximately
at the applied voltage of 5 V. An orthogonal vertical mirror with an extremely smooth surface texture was fabricated using KOH wet etching and a double-SOI (silicon-on-insulator) wafer with a (110) silicon wafer. The fabricated orthogonal vertical mirror was comprised of four pairs of two mutually orthogonal flat mirrors with
(thickness). The cross angles and surface roughness of the orthogonal vertical mirror were orthogonal, almost
and 3.523 nm rms, respectively. The proposed CCR was completed by combining the orthogonal vertical and horizontal actuated mirrors. Data transmission and modulation at a frequency of 10 Hz was successfully demonstrated using the fabricated CCR at a distance of approximately 50 cm.
The Development of an Electroconductive SiC-ZrB
Composite through Spark Plasma Sintering under Argon Atmosphere
Lee, Jung-Hoon ; Ju, Jin-Young ; Kim, Cheol-Ho ; Park, Jin-Hyoung ; Lee, Hee-Seung ; Shin, Yong-Deok ;
Journal of Electrical Engineering and Technology, volume 5, issue 2, 2010, Pages 342~351
DOI : 10.5370/JEET.2010.5.2.342
composites were fabricated by combining 30, 35, 40, 45 and 50 vol. % of zirconium diboride (
) powders with silicon carbide (SiC) matrix. The SiC-
composites and the sintered compacts were produced through spark plasma sintering (SPS) under argon atmosphere, and its physical, electrical, and mechanical properties were examined. Also, the thermal image analysis of the SiC-
composites was examined. Reactions between
were not observed via x-ray diffraction (XRD) analysis. The apparent porosity of the SiC+30vol.%
composites were 7.2546, 0.8920, 0.6038, 1.0981, and 10.0108%, respectively. The XRD phase analysis of the sintered compacts demonstrated a high phase of SiC and
. Among the
composites, the SiC+50vol.%
composite had the lowest flexural strength, 290.54MPa, the other composites had more than 980MPa flexural strength except the SiC+30vol.%
composite; the SiC+40vol.%
composite had the highest flexural strength, 1011.34MPa, at room temperature. The electrical properties of the SiC-
composites had positive temperature coefficient resistance (PTCR). The V-I characteristics of the SiC-
composites had a linear shape in the temperature range from room to
. The electrical resistivities of the SiC+30vol.%
, respectively, at room temperature, and their resistance temperature coefficients were
in the temperature range from room to
, respectively. Therefore, it is considered that among the sintered compacts the SiC+35vol.%
composites containing the most outstanding mechanical properties as well as PTCR and V-I characteristics can be used as an energy friendly ceramic heater or ohmic-contact electrode material through SPS.