Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Transactions of The Korean Institute of Electrical Engineers
Journal Basic Information
Journal DOI :
The Korean Institute of Electrical Engineers
Editor in Chief :
Volume & Issues
Volume 58, Issue 12 - Dec 2009
Volume 58, Issue 11 - Nov 2009
Volume 58, Issue 10 - Oct 2009
Volume 58, Issue 9 - Sep 2009
Volume 58, Issue 8 - Aug 2009
Volume 58, Issue 7 - Jul 2009
Volume 58, Issue 6 - Jun 2009
Volume 58, Issue 5 - May 2009
Volume 58, Issue 4 - Apr 2009
Volume 58, Issue 3 - Mar 2009
Volume 58, Issue 2 - Feb 2009
Volume 58, Issue 1 - Jan 2009
Selecting the target year
A Study of Re-Fuse Coordination Method of Distribution System with SFCL
Kim, Myoung-Hoo ; Kim, Jin-Seok ; You, Il-Kyoung ; Moon, Jong-Fil ; Lim, Sung-Hun ; Kim, Jae-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1835~1841
We analyze the problem of recloser-fuse coordination when a superconducting fault current limiter (SFCL) is installed to a power distribution system. Generally, The recloser is installed to upstream of fuse to protect against both permanent fault and temporary one appropriately. However, in a power distribution system with SFCL, the fault current is decreased by the effect of the impedance value of the SFCL and when a permanent fault occurs, the fuse may not melt during the last delay operation of the recloser because of the insufficient heat from the decreased current. Therefore, when SFCLs are applied into a power distribution system, the rating of the fuse has to be reselected to coordinate recloser to fuse effectively. To solve these problems, this paper analysed the operation of recloser-fuse coordination and presented the improved recloser-fuse coordination method in a power distribution system with SFCL using PSCAD/EMTDC.
Data Modeling for Developing the Baseline Network Analysis Software of Korean EMS System
Yun, Sang-Yun ; Cho, Yoon-Sung ; Lee, Wook-Hwa ; Lee, Jin ; Sohn, Jin-Man ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1842~1848
This paper summarizes a data modeling for developing the baseline network analysis software of the Korean energy management system (EMS). The study is concentrated on the following aspects. First, the data for operating the each application software are extracted. Some of the EMS network application softwares are selected for basis model. Those are based on the logical functions of each software and are not considered the other softwares. Second, the common data are extracted for equipment model and topological structure of power system in Korea. We propose the application common model(ACM) that can be applied whole EMS network application softwares. The ACM model includes the hierarchy and non-hierarchy power system structure, and is connected each other using the direct and indirect link. Proposed database model is tested using the Korea Electric Power Corporation(KEPCO) system. The real time SCADA data are provided for the test. Through the test, we verified that the proposed database structure can be effectively used to accomplish the Korean EMS system.
Development of a Compensating Algorithm for an Iron-cored Measurement CT using Flux-magnetizing Current Curves and Voltage-core Loss Current Curves
Kang, Yong-Cheol ; Zheng, Tai-Ying ; Kang, Hae-Gweon ; Lee, Byung-Eun ; Kim, Yong-Gyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1849~1854
This paper describes the design, evaluation and implementation of a compensating algorithm for an iron-cored measurement current transformer (CT) that removes the effects of the hysteresis characteristics of the iron-core. The exciting current resulting from the hysteresis characteristics of the core causes an error of the CT. The proposed algorithm decomposes the exciting current into the core loss current and the magnetizing current and each of them is estimated. The core loss current is calculated from the secondary voltage and the voltage-core loss current curve. The core flux linkage is calculated and then inserted into the flux-magnetizing current curve to estimate the magnetizing current. The exciting current at every sampling interval is obtained by summing the core loss and magnetizing currents and then added to the measured current to obtain the correct secondary current. The voltage-core loss current curve and flux-magnetizing current curves, which are different from the conventional curves, are derived in this paper. The performance of the proposed algorithm is validated under various conditions using EMTP generated data. The experimental test results of an iron-core type electronic CT, which consists of the iron-core and the compensation board, are also included. The results indicate that the proposed algorithm can improve the accuracy of the measurement CT significantly, and thus reduce the size and the cost of the CT.
Mother Wavelet Transform using Distribution Utility of Fault Point Extraction
Park, In-Deok ; Lee, Seung-Hwan ; Choi, Kwang-Jin ; Kim, Si-Kyung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1855~1860
This paper caused a distribution utility to generation of analysis fault several cases on the ground of substation in a energy meter three phase current, voltage data measurement to fault type and characteristics. Mother wavelet transformation of suitable to method algorithm from the distribution utility to generation of fault in image impedance etc several parameter for utility characteristics effective to probatory fault point extraction.
Simulated Analysis for the Transient Impedance Behaviors of Counterpoises Subjected to the Impulsive Currents
Joe, Jeong-Hyeon ; Lee, Bok-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1861~1868
A ground electrode subjected to lightning surge current shows the transient impedance behaviors. The ground electrode for protection against lightning should be evaluated in view of the transient grounding impedance and conventional grounding impedance, not ground resistance. The transient impedance characteristics of ground electrodes are influenced by the shape of ground electrode and the soil characteristics, as well as the waveform of lightning surge current. In order to propose a simulation method of analyzing the transient impedance characteristics of the grounding system in practical use, this paper suggests a theoretical analysis method of distributed parameter circuit model to simulate the transient impedance characteristics of counterpoise subjected to lightning surge current. EMTP and Matlab programs were employed to compute the transient grounding impedances of three counterpoises with different lengths. As a consequence, the simulated results using the proposed distributed parameter circuit model are in good agreement with the measured results.
A study on Reliability Enhancement Method and the Prediction Model Construction of Medium-Voltage Customers Causing Distribution Line Fault Using Data Mining Techniques
Bae, Sung-Hwan ; Kim, Ja-Hee ; Hong, Jung-Sik ; Lim, Han-Seung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1869~1880
Distribution line fault has been reduced gradually by the efforts on improving the quality of electrical materials and distribution system maintenance. However faults caused by medium voltage customers have been increased gradually even though we have done many efforts. The problem is that we don't know which customer will cause the fault. This paper presents the concept to find these customers using data mining techniques, which is based on accumulated fault records of medium voltage customers in the past. It also suggests the prediction model construction of medium voltage customers causing distribution line fault and methods to enhance the reliability of distribution system. We expect that we can effectively reduce faults resulted from medium voltage customers, which is 30% of total faults.
A Study on Overvoltage Reduction Method of Single Point Bonded Section on Combined Transmission Lines
Jung, Chae-Kyun ; Kang, Ji-Won ; Park, Hung-Sok ; Kim, Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1881~1887
This paper discusses the effects of ECC (Earth Continuity Conductor) for reducing the level of induced sheath overvoltages at the single point bonded section of combined transmission lines which are mixed underground power cable with overhead line in one T/L. In previous papers, the characteristics of ECC on only underground power cable systems were sufficiently analyzed. However, the result of only underground power cable systems are totally different from that of combined transmission lines because ECC is commonly grounded with overhead grounding wire at mesh of cable head. Therefore, in this paper, the installation effects of ECC have been variously analyzed considering the three kinds of fault positions, cable formation of duct and trefoil, spacing between phase conductor and ECC, and the change of overhead transmission line section length on 154kV combined transmission line. Finally, simulation results show that ECC can effectively reduce the induced sheath voltage.
Validation of Propagation Velocity through TDR Test in HVDC Submarine Cables
Jung, Chae-Kyun ; Park, Jun-Woo ; Moon, Kyoung-Hee ; Yang, Byeong-Mo ; Kang, Ji-Won ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1888~1894
This paper performs TDR real test for measurement of propagation velocity on #1 Pole of HVDC submarine cable section between Jeju and Haenam, and then measured velocity is compared with theoretical value and velocity provided from manufacturer. The measured velocity is also validated from theoretical process based on CIGRE simplified approach. In this paper, the fault location algorithm using multi-scale correlation of SWT(stationary wavelet transform) and travelling wave is additionally proposed for HVDC submarine cable system, it includes fault signal filter for noise cancellation. Finally, the measured velocity is validated from proposed fault location algorithm test once more.
A Study on Temperature and Tensile Load Analysis of Invar by Flame Exposure on Overhead Transmission Lines
Shin, Koo-Yong ; Jung, Chae-Kyun ; Lee, Sang-Yun ; Kang, Ji-Won ; Lee, Dong-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1895~1901
This paper describes the conductor temperature and tensile load analysis of invar by flame exposure on STACIR(Super Thermal-resistance Aluminium-alloy Conductors Reinforced) overhead transmission line based on real fault phenomena. Firstly, short-circuit fault by flame exposure is analysed by EMTP/ATP simulation, then the cutting causes of Al layer are also discussed. And then, the conductor temperature is calculated based on IEC 60949 according to 3 kinds of materials including invar, Al conductor and ACSR when same load current respectively flows in 3 kinds of material, they are compared each other. Finally, the tensile load tests are performed with various samples including new invar, used invar for a long time and invar exposed flame.
Development of Educational Simulator for Novel Network Reduction
Kim, Hyun-Houng ; Lee, Woo-Nam ; Kim, Wook ; Park, Jong-Bae ; Shin, Joong-Rin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1902~1910
This paper presents a graphical windows-based program for the education and training for novel network reduction. The object of developed simulator is to provide users with a simple and useable tool for gaining an intuitive feel for power system analysis. The developed simulator consists of the main module (MMI,GUI), the location marginal price module (LMP), the clustering module and network reduction module. Each module has a separate graphical and interactive interfacing window. The developed simulator needs with the PSS/E input data format, generator cost function, location information. Line admittances of reduced network was determined by using the power flow method(Newton-Raphson). So line flow of reduced network is almost same to original power system. Results of reduced network are compared on the window in the tabular format. Therefore, the developed simulator can be utilized as a useful tool for effective education and training for power system analysis.
Determining the Proper Capacity of Electric Vehicle Charging Station
Hong, Jun-Hee ; Choi, Jung-In ; Lee, Jong-Hyun ; Nam, Young-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1911~1915
The problem of determining the proper capacity of electric vehicle charging station is studied in the presented paper. Based on the expected arrival rate and the expected charging time, we calculate the proper capacity that guarantees electric vehicles get service better than a given lower bound which is termed the loss of charging probability. The problem is studied by using certain queueing models. We first formulate the problem as a queueless model of type M/M/n/n, known as the Erlang loss system. And then the M/M/n/K type queueing model is formulated to consider the parking space constraint. Results of the study may be used for designing the electric vehicle charging station.
An Overcurrent Analysis in Neutral Line and Algorithm to Prevent Malfunction of Relay in Distributed Generations
Shin, Dong-Yeol ; Kim, Dong-Myung ; Cha, Han-Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1916~1922
Introducing distributed generators(DGs) to utility distribution system can cause malfunction of relay on the grid when ground faults or severe load unbalances are occurred on the system. Because DGs interconnected to the grid can contribute fault currents and make bidirectional power flows on the system, fault currents from DGs can cause an interference of relay operation. A directional over current relay(DOCR) can determine the direction of power flow whether a fault occurs at the source side or load side through detecting the phases of voltage and current simultaneously. However, it is identified in this paper that the contributed fault current(Ifdg) from the ground source when was occurred to contribute single-line-to-ground(SLG) fault current, has various phases according to the distances from the ground source. It means that the directionality of Ifdg may not be determined by simply detecting the phases of voltage and current in some fault conditions. The magnitude of Ifdg can be estimated approximately as high as 3 times of a phase current and its maximum is up to 2,000 A depending on the capacity of generation facilities. In order to prevent malfunction of relay and damage of DG facilities from the contribution of ground fault currents, Ifdg should be limited within a proper range. Installation of neutral ground reactor (NGR) at a primary neutral of interconnection transformer was suggested in the paper. Capacity of the proposed NGR can be adjusted easily by controlling taps of the NGR. An algorithm for unidirectional relay was also proposed to prevent the malfunction of relay due to the fault current, Ifdg. By the algorithm, it is possible to determine the directionality of fault from measuring only the magnitude of fault current. It also implies that the directionality of fault can be detected by unidirectional relay without replacement of relay with the bidirectional relay.
Design of Cogging Torque and Torque Ripples Reduction for High Precision Controlled SPMSM
Kim, Chang-Ki ; Lee, Sang-Gon ; Jung, Sang-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1923~1929
The design of SPMSM(surface mounted permanent magnet synchronous motor) has been performed to reduce cogging torque and torque ripples. In general, cogging torque and torque ripples are affected by the shapes of teeth width, yoke depth, magnet pole arc, etc. Particularly, the minimum design point of cogging torque and torque ripples are different so that the design of SPMSM should be done to compromise both of them for precision application. In this paper, the design of PMSM for EPS(electric power steering) system is performed to verify the validity, and the design characteristics versus teeth width, yoke depth, and magnet pole arc are investigated in order to find out the minimum point of cogging torque and torque ripples. In addition, skew of PM is applied for cogging torque reduction.
Torque Ripple Reduction for Permanent Magnet Synchronous Motor using Harmonic Current Injection
Kwon, Soon-O ; Lee, Jeong-Jong ; Lee, Geun-Ho ; Hong, Jung-Pyo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1930~1935
This paper deals with the torque ripple reduction of permanent magnet synchronous motor using harmonic current injection. Torque ripple of electric motor reduces system stability and performances, therefore efforts to reduce torque ripple are exerted in the design process. Torque ripple can be reduced by appropriate pole/slot combination, skew of rotor or stator, design of magnetic circuit, etc. In addition, torque ripple can be also reduced by input voltage and current, and many researches have been conducted to reduce torque ripple for six-step drive. Torque ripple reduction for current vector controlled permanent magnet synchronous motor also have been conducted and verified by investigating back emf wave form. Torque ripple reduction in this paper started from getting torque profile according to input current and electrical angle calculated by FEA, then instantaneous currents at each electrical angles for constant torque are calculated and applied to experiments. Therefore, 0% of torque ripple can be obtained theoretically with harmonic current injection. In order to maximize the effect of torque ripple reduction, a BLDC motor having high harmonic component of back emf is chosen. With sinusoidal current drive, over 100% of torque ripple is obtained initially, then 0.5 % of torque ripple is obtained by FEA using harmonic current injection. The effect is verified by experiment and the presented method can be effectively applicable to Electric Power Steering(EPS).
Optimal Design of Dielectric shape and Topology using Smooth Boundary Topology Optimization Method
Jeung, Gi-Woo ; Choi, Nak-Sun ; Kim, Nam-Kyung ; Kim, Dong-Hun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1936~1941
This paper deals with a new methodology for topology optimization in which the topology of the design domain may change during the shape optimization process. To achieve this, the concept of the topological gradient is introduced to compute the sensitivity of an objective function when a small hole is drilled in the domain. Based on shape and topological sensitivity values, the shape and topology of the design domain may be simultaneously changed during design iterations if necessary. To verify the advantages and also to facilitate understanding of the method itself, two electrostatic design problems have been tested by using 2D finite element analysis: the first is the inverse problem of a simple dielectric model and the second is the rotor design of a MEMS actuator.
Yoke Shape Design of Claw-Poles Stepping Motor Using Modified Magnetic Equivalent Circuit Method Including Magnetic Saturation Effect and Leakage Flux
Lee, Hyung-Woo ; Cho, Su-Yeon ; Bae, Jae-Nam ; Son, Byoung-Ook ; Park, Kyoung-Jin ; Lee, Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1942~1946
This paper presents a shape design process of Claw-Poles Stepping Motor(CPSM) using Modified Magnetic Equivalent Circuit Method(MMEC). Because this motor is adopted on low power devices, the motor size is a very small type. But it have a very strong permanent magnet. So magnetic saturation effect happens on yoke teeth of CPSM. Also this magnetic saturation effect causes more leakage flux component between yoke tooth have another pole. In this motor type, it is essential to design a shape of yoke teeth for avoiding the magnetic saturation effect and the leakage flux. In this paper, MMEC including the magnetic saturation effect and the leakage flux component was used for design process. Comparing with data calculated by using the MMEC and results analyzed by 3-D FEM, it could be stated that the design process with MMEC was reasonable. Finally, the model has the optimized shape of yoke teeth was compared with a conventional model for no-load Back EMF and torque at steady-state operation.
Design of Dimmable electric ballast for the Ceramic metal halide lamp
Lim, Ki-Seung ; Choe, Hyeon-Hui ; Sin, Dong-Seok ; Park, Chong-Yun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1947~1953
Metal halide (MH) lamps have been largely used due to high luminous efficiency, good color rendering, and long life. Since the metal halide lamps have problems of high ignition voltage and acoustic resonance. Thus, the design of ballast is very difficult for engineers. This paper proposes prototype of electric ballast in order to solve above two problems. The proposed electric ballast is consisted of EMI filter, full wave rectifier circuit, active PFC, DBI(Dual Buck Inverter), dimming circuit and ignitor circuit. The DBI supplies both rectangular voltage and current to the lamp. As the result of the experiment, the acoustic resonance was eliminated and the ignitor circuit was designed to generate high ignition voltage than 5kV. It makes the dimming circuit possible to control the lamp power in range between 230W and 350W.
Development of Three-Phase Line-Interactive Dynamic Voltage Restorer with Hybrid Detection Method
Jeong, Jong-Kyou ; Han, Byung-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1954~1961
This paper describes the development of a three-phase line-interactive dynamic voltage restorer with hybrid detection method, which is composed of three H-bridge inverter modules and super-capacitors. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental works with a 3kVA prototype. The developed system can compensate the input voltage sag and interruption within 2ms. The maximum allowable duration of voltage interruption is about 4 seconds. The developed system can be effectively used to compensate the voltage interruption in the sensitive load, such as computer, communication devices, and automation devices, and medical equipment. The developed system has a simple structure to be easily implemented with commercially available components, and to be highly reliable in operation.
A Design of a Simulation Platform to Test PRT Vehicle Operational Control Algorithms Using On-board Embedded Process Board
Lee, Jun-Ho ; Jeong, Rac-Gyo ; Kim, Yong-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1962~1967
This paper deals with a design of a platform to simulate PRT vehicle operational control algorithms using on-board embedded process board. The configuration of the platform is composed of the central control module, the station control module, man-machine interface and monitoring module. Since PRT system needs inherently very reliable vehicle operational control algorithm in order to avoid the impact between vehicles, it is very important to construct a simulation platform to test a designed vehicle operational control algorithm during the development process For the test of the proposed platform a path of the each moving vehicle is predefined in the central control system before the dispatch order is given to the vehicle. The simulation results show the effectiveness of the proposed simulation platform for test and evaluation of the PRT operational control algorithms.
MPPT Control of Photovoltaic by FNN
Choi, Jung-Sik ; Ko, Jae-Sub ; Chung, Dong-Hwa ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1968~1975
The paper proposes a novel control algorithm for tracking maximum power of PV generation system.. The maximum power of PV array is determinated by a insolation and temperature. Prior considered the term in PV generation system is how maximum power point(MPP) is accurately tracked.. The paper proposes a fuzzy neural network(FNN) control algorithm so as to accurately track those maximum power points. The proposed control algorithm comprises the antecedence part of fuzzy rule and clustering method, multi-layer neural network in the consequent part. FNN has the advantages which are depicted both high performance and robustness in fuzzy control and high adaptive control in neural network.. Specially, it can show the outstanding control performance for parameter variations appling to non-linear character of PV array. In this paper, the tracking speed and the accuracy prove the validity through comparing a proposed algorithm with a conventional one.
Electrical, Structural, Optical Properties of the AZO Transparent Conducting Oxide Layer for Application to Flat Panel Display
No, Im-Jun ; Kim, Sung-Hyun ; Park, Dong-Wha ; Shin, Paik-Kyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1976~1981
Transparent conducting aluminum-doped zinc oxide (AZO) thin films were deposited on Coming glass substrate using an Gun-type rf magnetron sputtering deposition technology. The AZO thin films were fabricated with an AZO ceramic target (Zn: 98wt.%,
: 2wt.%). The AZO thin films were deposited with various growth conditions such as the substrate temperature, oxygen pressure. X -ray diffraction (XRD), UV/visible spectroscope, atomic force microscope (AFM), and Hall effect measurement system were done in order to investigate the properties of the AZO thin films Among the AZO thin films prepared in this study, the one formed at conditions of the substrate temperature
, Ar 50 sccm,
5 sccm and working pressure 5 motor showed the best properties of an electrical resistivity of
, a carrier concentration of
, and a carrier mobility of
, which indicates that it could be used as a transparent electrode for thin film transistor and flat panel display applications.
A Study on Metal Oxide based Humidity Sensor with Excellent Humidity Sensing Characteristics
You, Do-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1982~1988
films are fabricated using silk printing method. Heat treatment temperature of films is 600[
]. From the analysis of microstructure, grain size of
films is about
. Thickness of films is 30.19[
] and surface uniformity of films is good. From the analysis of crystalline structure,
films transform anatase phase to rutile phase. Capacitance of films increases according to increase relative humidity and decrease measuring frequency. Hysteresis characteristics of capacitance and impedance are best at 45[%RH] and 75[%RH] respectively. Impedance of films increases according to decrease measuring frequency.
The Property Analysis of Ceramic Metal-Halide Lamp Considering Acoustic Resonance Phenomenon and Design of Inverter by the PSpice Simulation
Jang, Hyeok-Jin ; Kim, Nam-Goon ; Yang, Jong-Kyung ; Lee, Jong-Chan ; Park, Dae-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1989~1994
This study purposes are improvement of system (lamp & ballast) efficacy with and optical characteristics through the developed ceramic arc tube. The designed electronic ballast is substituted for conventional magnetic ballast. These electric signal and optical, thermal characteristics through the improving efficacy of lighting system compared with conventional magnetic ballast. properties of lamp by driving method is researching in ballast. Particularly, electronic ballasts, which improved against weakness of Magnetic Ballast, are researching and applying to control of ceramic metal-halide lamp. but One major limitation is the acoustic resonance problem in CMH lamps at high-frequency operation. In order to avoid acoustic resonance, driving frequency decided 21[kHz]. Before discharge in this paper. The PSpice simulation result obtained sufficient voltage gain and the ignition voltage obtained over 3[kV] at 75[kHz]. After discharge, driving voltage obtained approximately 90[Vrms] at 21[kHz].
Electrical Life Time Constant Estimation of Ceramic Element for Sensor
Jeong, Joo-Young ; Kang, Dong-Sik ; Sun, Jong-Ho ; Heo, Jong-Cheol ; Choo, Young-Bae ; Park, Chung-Hoo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 1995~1999
A partial discharge(PD) measurement is a very effective method to assess the insulation condition of high-voltage machines. It is necessary that the life time of the on-line PD measurement sensor is assessed. Therefore, the electrical life time assessment method of ceramic element was reviewed in order to estimate the life time of the on-line PD measurement sensor. The samples were prepared according to the reviewed method and were tested at 8kV, 9kV and 10kV. Based on the obtained results, the life time constant is shown above 59. Also, it is assumed that the estimated life time constant can be used to anticipate the life time and to assess the conformity of the on-line PD measurement sensor.
Characteristics of Ultra High Frequency Partial Discharge Signals of Turn to Turn Defect in Transformer Oil
Yoon, Jin-Yul ; Ju, Hyung-Jun ; Goo, Sun-Geun ; Park, Ki-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2000~2004
In general, for the condition monitoring of a power transformer using the UHF PD measuring technique, detection of any partial discharge, identifying the defect in the transformer and locating the insulation defect are necessary. In this paper one of the most frequent detects which can result in turn to turn fault in power transformer was examined for identifying the defect. In order to model the defect, as a discharge source, a partial discharge cell was used for experimental activity. Magnitude of electromagnetic wave signals and corresponding amount of apparent discharge were measured simultaneously against phase of applied voltage to the discharge cell. Frequency range and phase resolved partial discharge signals were measured and analyzed. The results will be contributed to build the defect database of power transformer and to decrease the occurrence of transformer faults.
Water Droplet Ejection Characteristics of a Wet Porous Point-Plate Airgap
Jung, Jae-Seung ; Lee, Woo-Seok ; Moon, Jae-Duk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2005~2010
Water droplet ejection characteristics of a point-to-plate airgap, with a wet porous point as a corona electrode, has been investigated. And the water droplet traces, charge, mass and number were measured experimentally. More particles are observed with wet porous point than metal point because the corona-discharging wet porous point can eject a number of water droplets. The water droplets ejected from the positive-corona-discharging wet porous point showed very fine traces as compared with those from the negative-corona-discharging wet porous point. Moreover, the water droplets ejected from the AC-corona-discharging wet porous point showed granular-like larger traces. It was shown that the weak corona discharge can eject smaller water droplets with larger ratio of mass-to-charge than the intense corona discharge.
Analysis of Space Charge Propagation in a Dielectric liquid Employing Field-Thermal Electron Emission Model and Finite Element Method
Lee, Ho-Young ; Lee, Se-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2011~2015
In an insulating dielectric liquid such as transformer oil, space charge injection and propagation were analyzed under the Fowler-Nordheim and Richardson-Dushman's thermal emission charge injection conditions for blade-plane electrodes stressed by a step voltage. The governing equations were composed of all five equations such as the Poisson's equation for electric fields, three continuity equations for electrons, negative, and positive ions, and energy balanced equation for temperature distributions. The governing equations for each carrier, the continuity equations, belong to the hyperbolic-type PDE of which the solution has a step change at the space charge front resulting in numerical instabilities. To decrease these instabilities, the governing equations were solved simultaneously by the Finite Element Method (FEM) employing the artificial diffusion scheme as a stabilization technique. Additionally, the terminal current was calculated by using the generalized energy method which is based on the Poynting's theorem, and represents more reliable and stable approach for evaluating discharge current. To verify the proposed method, the discharge phenomena were successfully applied to the blade~plane electrodes, where the radius of blade cap was
Design a Dual-band Microstrip Antenna using Slots
Ko, Hyun-Jung ; Kim, Won-Kyu ; Shin, Jae-Cheol ; Lee, Hak-Yong ; Chung, Young-Seek ; Cheon, Chang-Yul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2016~2021
In this paper, a dual-band antenna aimed for a mobile communication repeater was designed and measured. The operating frequency ranges are GSM(870
960 MHz) and WCDMA(1920
2170 MHz) bands. Experimental and numerical studies are performed for various design variables such as slot lengths. Using two meandering slots in the ground plane, we can obtain two higher resonant frequencies significantly with broader bandwidths. The measured maximum gain of antenna is 2 dBi in the GSM band and 2.45 dBi in the WCDMA band.
A Study of Superheater Temperature Control on an Once Through Boiler in Thermal Power Plant
Lee, Jo-Hyun ; Jeong, Tae-Won ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2022~2027
An supercritical once through boiler system has been used in the korea standard-type thermal power plant. It is critical in boiler operation that superheater temperature should be controlled within the specified limit. In this paper, control logic scheme is suggested for superheater temperature in once through boiler. Finally the simulation result using process model based simulator shows the validity of suggested control logic.
Simulator for a Micro-Turbine during Start-up by Constant Power Output Motoring Method using Starter
Rho, Min-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2028~2037
This paper presents the simulator for dynamic modeling of a MT(micro turbine) during start-up period. The simulator is implemented by modeling a dynamic power of main components of a MT including compressor, combustor and turbine. A modeling for a MT under steady state operation can be accurately built from thermodynamics analysis. But dynamic modeling during start-up period is very difficult because efficiency of main components is very low and the designed value has big error and nonlinear characteristics during start-up. In this paper, new method without using thermodynamics analysis during start-up is proposed for the simulator. The power models of main components are derived from analysis of the experimental operation data by test motoring using a electric starter under constant power output. The simulator is developed using MATLAB/Simulink. For constant power output control, sensorless vector inverter is designed and algorithms for starting from stall and method for controling a output power are proposed. The performance of developed simulator is verified by comparing experimental and simulation start-up results.
Robust Current Estimation of DC/DC Boost Converter against Load Variation
Kim, In-Hyuk ; Jeong, Goo-Jong ; Son, Young-Ik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2038~2040
This paper studies the state estimation problem for the current of DC/DC boost converters with parasitic inductor resistance. The parasitic resistance increases the system uncertainty when the output load variation occurs. In order to enhance the observation performance of the Luenberger observer this paper includes the integral of the estimation error signal to the estimation algorithm. By using the proposed PI observer the converter current signal is successfully reconstructed with the voltage measurement regardless of the load uncertainty. Computer simulation has been carried out by using Simulink/Sim Power System. Simulation results show the proposed method maintains robust estimation performance against the model uncertainty.
Feature Point Extraction of Hand Region Using Vision
Jeong, Hyun-Suk ; Joo, Young-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2041~2046
In this paper, we propose the feature points extraction method of hand region using vision. To do this, first, we find the HCbCr color model by using HSI and YCbCr color model. Second, we extract the hand region by using the HCbCr color model and the fuzzy color filter. Third, we extract the exact hand region by applying labeling algorithm to extracted hand region. Fourth, after finding the center of gravity of extracted hand region, we obtain the first feature points by using Canny edge, chain code, and DP method. And then, we obtain the feature points of hand region by applying the convex hull method to the extracted first feature points. Finally, we demonstrate the effectiveness and feasibility of the proposed method through some experiments.
Localization on WSN Using Fuzzy Model and Kalman Filter
Kim, Jong-Seon ; Joo, Young-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2047~2051
In this paper, we propose the localization method on WSN(Wireless Sensor Network) using fuzzy model and Kalman filter. The proposed method is as follows: First, we estimate the distance of RSSI(Receive Signal Strength Index) by using fuzzy model in order to minimize the distance error. Second, we use a triangulation measurement for estimating the localization. And then, we minimize the localization error using a Kalman filter. Finally, we show the effectiveness and feasibility of the proposed method through some experiments.
Design of XML based Information Exchange Format for Consumer Service
Oh, Do-Eun ; Kim, Sun-Ic ; Song, Jae-Ju ; Yang, Il-Kwon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2052~2058
The standardized and open information model called common language and information exchange format should be firstly defined for the interoperable power system and two-way information exchange among the components of the power system. The information models and information exchange formats for power facilities and power system applications are being defined in power system area, but the information model and information exchange format for the consumer area are not being yet defined besides of metering information model. An architecture and open standard for the information exchange between energy service provider and consumer are required to provide various value added services through the networking with devices in consumer premise. In this paper, an architecture for the two-way communications between energy service provider and consumer is defined and psXML(power system XML) for the information exchange is designed.
A SoC Based on a Neural Network for Embedded Smart Applications
Lee, Bong-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2059~2063
This paper presents a programmable System-On-a-chip (SoC) for various embedded smart applications that need Neural Network computations. The system is fully implemented into a prototyping platform based on Field Programmable Gate Array (FPGA). The SoC consists of an embedded processor core and a reconfigurable hardware accelerator for neural computations. The performance of the SoC is evaluated using a real image processing application, an optical character recognition (OCR) system.
Representation of Apparent Power of Non-sinusoidal Multi-line Power System Using Geometric Algebra
Jeon, Seong-Jeub ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2064~2070
According to recent researches, apparent power in a non-sinusoidal single phase system can be represented with geometric algebra. In this paper, the geometric algebra is applied to apparent power defined in a multi-line system having transmission lines with frequency-dependency under non-sinusoidal conditions.
Abdominal Wall Motion-Based Respiration Rate Measurement using An Ultrasonic Proximity Sensor
Min, Se-Dong ; Kim, Jin-Kwon ; Shin, Hang-Sik ; Yun, Young-Hyun ; Lee, Chung-Keun ; Lee, Jeong-Whan ; Lee, Myoung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 10, 2009, Pages 2071~2078
In this paper, we proposed a non-contact respiration measurement system with ultrasonic proximity sensor. Ultrasonic proximity sensor approach of respiration measurement which respiration signatures and rates can be derived in real-time for long-term monitoring is presented. 240 kHz ultrasonic sensor has been applied for the proposed measurement system. The time of flight of sound wave between the transmitted signal and received signal have been used for a respiration measurement from abdominal area. Respiration rates measured with the ultrasonic proximity sensor were compared with those measured with standard techniques on 5 human subjects. Accurate measurement of respiration rate is shown from the 50 cm measurement distance. The data from the method comparison study is used to confirm the performance of the proposed measurement system. The current version of respiratory rate detection system using ultrasonic can successfully measure respiration rate. The proposed measurement method could be used for monitoring unconscious persons from a relatively close range, avoiding the need to apply electrodes or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using ultrasonic sensor offers a promising possibility of non-contact measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range of the measurement and quality of the rate-finding for broadening the potential application areas of this technology.