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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 7, Issue 6 - Nov 2012
Volume 7, Issue 5 - Sep 2012
Volume 7, Issue 4 - Jul 2012
Volume 7, Issue 3 - May 2012
Volume 7, Issue 2 - Mar 2012
Volume 7, Issue 1 - Jan 2012
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A Novel Control Strategy of Three-phase, Four-wire UPQC for Power Quality Improvement
Pal, Yash ; Swarup, A. ; Singh, Bhim ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 1~8
DOI : 10.5370/JEET.2012.7.1.1
The current paper presents a novel control strategy of a three-phase, four-wire Unified Power Quality (UPQC) to improve power quality. The UPQC is realized by the integration of series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt APF is carried out using a three-phase, four-leg Voltage Source Inverter (VSI), and the series APF is realized using a three-phase, three-leg VSI. To extract the fundamental source voltages as reference signals for series APF, a zero-crossing detector and sample-and-hold circuits are used. For the control of shunt APF, a simple scheme based on the real component of fundamental load current (I
) with reduced numbers of current sensors is applied. The performance of the applied control algorithm is evaluated in terms of power-factor correction, source neutral current mitigation, load balancing, and mitigation of voltage and current harmonics in a three-phase, four-wire distribution system for different combinations of linear and non-linear loads. The reference signals and sensed signals are used in a hysteresis controller to generate switching signals for shunt and series APFs. In this proposed UPQC control scheme, the current/voltage control is applied to the fundamental supply currents/voltages instead of fast-changing APF currents/voltages, thus reducing the computational delay and the required sensors. MATLAB/Simulink-based simulations that support the functionality of the UPQC are obtained.
Phasor Discrete Particle Swarm Optimization Algorithm to Configure Micro-grids
Bae, In-Su ; Kim, Jin-O ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 9~16
DOI : 10.5370/JEET.2012.7.1.9
The present study presents the Phasor Discrete Particle Swarm Optimization (PDPSO) algorithm, an effective optimization technique, the multi-dimensional vectors of which consist of magnitudes and phase angles. PDPSO is employed in the configuration of micro-grids. Micro-grids are concepts of distribution system that directly unifies customers and distributed generations (DGs). Micro-grids could supply electric power to customers and conduct power transaction via a power market by operating economic dispatch of diverse cost functions through several DGs. If a large number of micro-grids exist in one distribution system, the algorithm needs to adjust the configuration of numerous micro-grids in order to supply electric power with minimum generation cost for all customers under the distribution system.
Evaluation of Two Lagrangian Dual Optimization Algorithms for Large-Scale Unit Commitment Problems
Fan, Wen ; Liao, Yuan ; Lee, Jong-Beom ; Kim, Yong-Kab ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 17~22
DOI : 10.5370/JEET.2012.7.1.17
Lagrangian relaxation is the most widely adopted method for solving unit commitment (UC) problems. It consists of two steps: dual optimization and primal feasible solution construction. The dual optimization step is crucial in determining the overall performance of the solution. This paper intends to evaluate two dual optimization methods - one based on subgradient (SG) and the other based on the cutting plane. Large-scale UC problems with hundreds of thousands of variables and constraints have been generated for evaluation purposes. It is found that the evaluated SG method yields very promising results.
Development of a Live-line Insulator Inspection Tool System for 154 kV Power Transmission Lines
Lee, Jae-Kyung ; Park, Joon-Young ; Cho, Byung-Hak ; Oh, Ki-Yong ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 23~33
DOI : 10.5370/JEET.2012.7.1.23
The current paper deals with a new live-line insulator inspection tool system that will be used by the Korea Electric Power Corporation for its 154 kV power transmission lines in 2011. Unlike the existing contact type tools, the developed inspection tool automates parts of the insulator inspection process using a sensor and an actuator. The tool sustains its weight independently, not by a lineman. In addition, the inspection tool measures the insulation resistance of an insulator together with its distribution voltage, thus providing more information for analysis and diagnosis. Such characteristics improve the system's operation efficiency, measurement reliability, and usability. We confirmed its effectiveness through live-line field tests with actual power transmission lines.
Speed Control of Linear Induction Motor using Sliding Mode Controller Considering the End Effects
Boucheta, A. ; Bousserhane, I.K. ; Hazzab, A. ; Sicard, P. ; Fellah, M.K. ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 34~45
DOI : 10.5370/JEET.2012.7.1.34
In the present paper, the mover speed control of a linear induction motor (LIM) using a sliding mode control design is proposed, considering the end effects. First, the indirect field-oriented control LIM is derived, considering the end effects. The sliding mode control design is then investigated to achieve speed- and flux-tracking under load thrust force disturbance. The numerical simulation results of the proposed scheme present good performances in comparison to that of the classical sliding mode control.
Reliability Assessment on Different Designs of a SMES System Based on the Reliability Index Approach
Kim, Dong-Wook ; Sung, Young-Hwa ; Jeung, Gi-Woo ; Jung, Sang-Sik ; Kim, Hong-Joon ; Kim, Dong-Hun ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 46~50
DOI : 10.5370/JEET.2012.7.1.46
The current paper presents an effective methodology for assessing the reliability of electromagnetic designs when considering uncertainties of design variables. To achieve this goal, the reliability index approach based on the first-order reliability method is adopted to deal with probabilistic constraint functions, which are expressed in terms of random design variables. The proposed method is applied to three different designs of a superconducting magnetic energy storage system that corresponds to initial, deterministic, and roust designs. The validity and efficiency of the method is investigated with reference values obtained from Monte Carlo simulation.
DC Appliance Safety Standards Guideline through Comparative Analysis of AC and DC Supplied Home Appliances
Ahn, Jung-Hoon ; Kim, Dong-Hee ; Lee, Byoung-Kuk ; Jin, Hyun-Cheol ; Shim, Jae-Sun ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 51~57
DOI : 10.5370/JEET.2012.7.1.51
This paper provides a safety guideline for DC supplied home appliances through the comparative analysis of existing safety guideline for AC supplied home appliances. For this purpose, a predictive DC home appliance model is suggested and in special international safety standards of AC appliances are also analyzed. Moreover, a DC distribution system is built to verify the validity of the proposed safety guideline. The detailed analyzing process is explained with help of informative experimental results.
Shape Optimization of a Thomson Coil Actuator for Fast Response Using Topology Modification
Li, Wei ; Koh, Chang-Seop ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 58~63
DOI : 10.5370/JEET.2012.7.1.58
The shape optimization of a Thomson coil actuator used in an arc eliminator is done for fast response by adopting topology modification method. The displacement of the plate in a fixed calculation time is taken as the objective function. The objective function and contribution factor are calculated by using an adaptive equivalent circuit method which has been proved accurate and efficient. Both shape optimization and performance analysis are accomplished based on the segmentation of plate. Through the refinement of the sensitive segments a precise optimal plate shape can be obtained. The effectiveness of the proposed method is proved by the comparison of results before and after the shape optimization.
Shape Optimization for Interior Permanent Magnet Motor based on Hybrid Algorithm
Yim, Woo-Gyong ; An, Kwang-Ok ; Seo, Jang-Ho ; Kim, Min-Jae ; Jung, Hyun-Kyo ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 64~68
DOI : 10.5370/JEET.2012.7.1.64
In this paper, a design method for minimizing the cogging torque of an Interior Permanent Magnet Motor (IPM) is proposed based on a hybrid algorithm. The suggested optimization algorithm is based on a combination of the Response Surface Method (RSM) and Simplex Method. The results show that the proposed method provides improved characteristics compared to the conventional methods, such as a shorter calculation time and the acquisition of a more correct solution.
Optimal Design of a Distributed Winding Type Axial Flux Permanent Magnet Synchronous Generator
You, Yong-Min ; Lin, Hai ; Kwon, Byung-Il ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 69~74
DOI : 10.5370/JEET.2012.7.1.69
This paper presents a distributed winding type axial flux permanent magnet synchronous generator (AFPMSG) with reduced the total harmonic distortion (THD), suitable for wind turbine generation systems. Although the THD of the proposed distributed winding type is more reduced than the concentrated winding type, the unbalance of the phase back EMF occurs. To improve the unbalance of the phase back EMF and the output power of the distributed winding type AFPMSG, the Kriging based on the latin hypercube sampling (LHS) is utilized. Finally, these optimization results are confirmed by experimental results. As a result, the unbalance of the phase back EMF and the output power of the distributed winding type AFPMSG were improved while maintaining the total harmonic distortion (THD) and the average phase back EMF.
Electric Field Energy Harvesting Powered Wireless Sensors for Smart Grid
Chang, Keun-Su ; Kang, Sung-Muk ; Park, Kyung-Jin ; Shin, Seung-Hwan ; Kim, Hyeong-Seok ; Kim, Ho-Seong ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 75~80
DOI : 10.5370/JEET.2012.7.1.75
In this paper, a new energy harvesting technology using stray electric field of an electric power line is presented. It is found that energy can be harvested and stored in the storage capacitor that is connected to a cylindrical aluminum foil wrapped around a commercial insulated 220 V power line. The average current flowing into 47
storage capacitor is about 4.53
with 60 cm long cylindrical aluminum foil, and it is possible to operate wireless sensor node to transmit RF data every 42 seconds. The harvested average power is about 47
in this case. Since the energy can be harvested without removing insulating sheath, it is believed that the proposed harvesting technology can be applied to power the sensor nodes in wireless ubiquitous sensor network and smart grid system.
Wideband VHF and UHF RF Front-End Receiver for DVB-H Application
Park, Joon-Hong ; Kim, Sun-Youl ; Ho, Min-Hye ; Baek, Dong-Hyun ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 81~85
DOI : 10.5370/JEET.2012.7.1.81
This paper presents a wideband and low-noise direct conversion front-end receiver supporting VHF and UHFbands simultaneously. The receiver iscomposed of a low-noise amplifier (LNA), a down conversion quadrature mixer, and a frequency divider by 2. The cascode configuration with the resistor feedback is exploited in the LNA to achieve a wide operating bandwidth. Four gainstep modesare employed using a switched resistor bank and a capacitor bank in the signal path to cope with wide dynamic input power range. The verticalbipolar junction transistors are used as the switching elements in the mixer to reduce 1/f noise corner frequency. The proposed front-end receiver fabricated in 0.18
CMOS technology shows very low minimum noise figureof 1.8 dB and third order input intercept pointof -12dBm inthe high-gain mode of 26.5 dBmeasured at 500 MHz.The proposed receiverconsumeslow current of 20 mA from a 1.8 V power supply.
Calculation of the Reactor Impedance of a Planar-type Inductively Coupled Plasma Source
Kwon, Deuk-Chul ; Jung, Bong-Sam ; Yoon, Nam-Sik ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 86~90
DOI : 10.5370/JEET.2012.7.1.86
A two-dimensional nonlocal heating theory of planar-type inductively coupled plasma source has been previously reported with a filamentary antenna current model. However, such model yields an infinite value of electric field at the antenna position, resulting in the infinite self-inductance of the antenna. To overcome this problem, a surface current model of antenna should be adopted in the calculation of the electromagnetic fields. In the present study, the reactor impedance is calculated based on the surface current model and the dependence on various discharge parameters is studied. In addition, a simpler method is suggested and compared with the surface current calculation.
Characterization of Silver Inkjet Overlap-printing through Cohesion and Adhesion
Lee, Sang-Ho ; Cho, Young-June ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 91~96
DOI : 10.5370/JEET.2012.7.1.91
We introduce an understanding of silver (Ag) inkjet overlap-printing characteristics from the viewpoints of cohesion between ink droplets and adhesion between an ink droplet and a surface. The printing characteristics were closely monitored by changing the surface energy to elucidate the effect of adhesion and cohesion on printing instability, such as droplet merging and line bulging. The surface energy of the substrate was changed through the hydrophilization of a hydrophobic fluorocarbon-coated surface. The surface energy and ink wettability of the prepared surfaces were characterized using sessile drop contact angle analysis, and printing instability was observed using an optical microscope after drop-on-demand inkjet printing with a 50% overlap in diameter of deposited singlet patterns. We found that the surface energy is not an appropriate indicator based on the experimental results of Ag ink printing on a hydrofluoric-treated silicon surface. The analytical approach using adhesion and cohesion was helpful in understanding the instability of the inkjet overlap-printing, as adhesion and cohesion represent the direct interfacial relationship between the Ag inks used and the substrate.
Accurate Prediction Method of Breakdown Voltage in Air at Atmospheric Pressure
Kim, Nam-Kyung ; Lee, Se-Hee ; Georghiou, G.E. ; Kim, Dong-Wook ; Kim, Dong-Hun ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 97~102
DOI : 10.5370/JEET.2012.7.1.97
To predict accurately the breakdown voltage in air at atmospheric pressure, a fully coupled finite element analysis combining the hydrodynamic diffusion-drift equations with Poisson's equation is proposed in the current paper. As three kinds of charged transport particles are nonlinearly coupled with spatial electric fields, the equations should be solved by an iterative numerical scheme, in which secondary effects, such as photoemission and photoionization, are considered. The proposed method has been successfully applied to evaluate the breakdown voltage in circular parallel-plane electrodes. Its validity has been proved through the comparison of the predicted and experimental results. The effects of numerical conditions of the initial charge, photoemission, and background ionization on the discharge phenomena are quantitatively assessed through Taguchi's design of experiment method.
Considerations on the Long-term Reliability of On-line Partial Discharge Ceramic Sensor for Thermal Power Generators and its Demonstration in the Field
Sun, Jong-Ho ; Youn, Young-Woo ; Hwang, Don-Ha ; Kang, Dong-Sik ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 103~108
DOI : 10.5370/JEET.2012.7.1.103
The present study describes the considerations on the long-term reliability of the on-line partial discharge (PD) ceramic sensor for thermal power generators. Voltage acceleration aging tests were carried out under continuous and impulsive thermal aging at more than
, considering the practical service environment. Experimental results show that the sensors have a life that could last for more than 100 years, excellent dielectric characteristics, and insulation strength. In addition, the ceramic on-line PD sensors were installed in a thermal power generator in Korea for demonstration. The results of the PD calibration and test voltage application prove that the on-line ceramic sensors have satisfactory performances for on-line PD measurement.
Training HMM Structure and Parameters with Genetic Algorithm and Harmony Search Algorithm
Ko, Kwang-Eun ; Park, Seung-Min ; Park, Jun-Heong ; Sim, Kwee-Bo ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 109~114
DOI : 10.5370/JEET.2012.7.1.109
In this paper, we utilize training strategy of hidden Markov model (HMM) to use in versatile issues such as classification of time-series sequential data such as electric transient disturbance problem in power system. For this, an automatic means of optimizing HMMs would be highly desirable, but it raises important issues: model interpretation and complexity control. With this in mind, we explore the possibility of using genetic algorithm (GA) and harmony search (HS) algorithm for optimizing the HMM. GA is flexible to allow incorporating other methods, such as Baum-Welch, within their cycle. Furthermore, operators that alter the structure of HMMs can be designed to simple structures. HS algorithm with parameter-setting free technique is proper for optimizing the parameters of HMM. HS algorithm is flexible so as to allow the elimination of requiring tedious parameter assigning efforts. In this paper, a sequential data analysis simulation is illustrated, and the optimized-HMMs are evaluated. The optimized HMM was capable of classifying a sequential data set for testing compared with the normal HMM.
Context-aware Video Surveillance System
An, Tae-Ki ; Kim, Moon-Hyun ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 115~123
DOI : 10.5370/JEET.2012.7.1.115
A video analysis system used to detect events in video streams generally has several processes, including object detection, object trajectories analysis, and recognition of the trajectories by comparison with an a priori trained model. However, these processes do not work well in a complex environment that has many occlusions, mirror effects, and/or shadow effects. We propose a new approach to a context-aware video surveillance system to detect predefined contexts in video streams. The proposed system consists of two modules: a feature extractor and a context recognizer. The feature extractor calculates the moving energy that represents the amount of moving objects in a video stream and the stationary energy that represents the amount of still objects in a video stream. We represent situations and events as motion changes and stationary energy in video streams. The context recognizer determines whether predefined contexts are included in video streams using the extracted moving and stationary energies from a feature extractor. To train each context model and recognize predefined contexts in video streams, we propose and use a new ensemble classifier based on the AdaBoost algorithm, DAdaBoost, which is one of the most famous ensemble classifier algorithms. Our proposed approach is expected to be a robust method in more complex environments that have a mirror effect and/or a shadow effect.
Stability of LTI Systems with Unstructured Uncertainty Using Quadratic Disc Criterion
Yeom, Dong-Hae ; Park, Jin-Bae ; Joo, Young-Hoon ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 124~131
DOI : 10.5370/JEET.2012.7.1.124
This paper deals with robust stability of linear time-invariant (LTI) systems with unstructured uncertainties. A new relation between uncertainties and system poles perturbed by the uncertainties is derived from a graphical analysis. A stability criterion for LTI systems with uncertainties is proposed based on this result. The migration range of the poles in the proposed criterion is represented as the bound of uncertainties, the condition number of a system matrix, and the disc containing the poles of a given nominal system. Unlike the existing methods depending on the solutions of algebraic matrix equations, the proposed criterion provides a simpler way which does not involves algebraic matrix equations, and a more flexible root clustering approach by means of adjusting the center and the radius of the disc as well as the condition number.
Aerodynamic Derivatives Identification Using a Non-Conservative Robust Kalman Filter
Lee, Han-Sung ; Ra, Won-Sang ; Lee, Jang-Gyu ; Song, Yong-Kyu ; Whang, Ick-Ho ;
Journal of Electrical Engineering and Technology, volume 7, issue 1, 2012, Pages 132~140
DOI : 10.5370/JEET.2012.7.1.132
A non-conservative robust Kalman filter (NCRKF) is applied to flight data to identify the aerodynamic derivatives of an unmanned autonomous vehicle (UAV). The NCRKF is formulated using UAV lateral motion data and then compared with results from the conventional Kalman filter (KF) and the recursive least square (RLS) method. A superior performance for the NCRKF is demonstrated by simulation and real flight data. The NCRKF is especially effective in large uncertainties in vehicle modeling and in measuring flight data. Thus, it is expected to be useful in missile and aircraft parameter identification.