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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of The Korean Institute of Electrical Engineers
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 60, Issue 12 - Dec 2011
Volume 60, Issue 11 - Nov 2011
Volume 60, Issue 10 - Oct 2011
Volume 60, Issue 9 - Sep 2011
Volume 60, Issue 8 - Aug 2011
Volume 60, Issue 7 - Jul 2011
Volume 60, Issue 6 - Jun 2011
Volume 60, Issue 5 - May 2011
Volume 60, Issue 4 - Apr 2011
Volume 60, Issue 3 - Mar 2011
Volume 60, Issue 2 - Feb 2011
Volume 60, Issue 1 - Jan 2011
Selecting the target year
A Study on Calculation of Combined Heat and Power on Standpoint of Nation and Independent Power Producers
Kim, Yong-Ha ; Lee, Pyong-Ho ; Kim, Young-Gil ; Jo, Hyun-Mi ; Woo, Sung-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 905~912
DOI : 10.5370/KIEE.2011.60.5.905
In this paper, the method on calculating benefits of combined heat and power is introduced for standard evaluation in electrical power system. This paper calculates benefits about new national viewpoint and viewpoint of independent power producers and assesses benefits of combined heat and power in Korea and In Seoul national capital area. Benefit costs are composed of avoid cost of centralized generation, line upgrading adjustment, loss adjustment and electrical power trade cost per year in earlier study, in addition trade cost of
, construction cost of combined heat and power for accurate calculation. Benefit of combined heat and power is calculated by simulation results of real electrical power system.
A Study About Distribution Automation System Based on CIM
Lee, Hee-Joo ; Seo, Jeong-Il ; Han, Ju-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 913~920
DOI : 10.5370/KIEE.2011.60.5.913
Distribution systems for operating the various systems should be operated organically. Distribution systems for organic operations extend the functionality of the system and system integration for the extension is doing. However, in systems integration for each unique non-standard definition of linkage and exchange systems are used. Non-standard definition of a unique linkage and exchange systems in the maintenance and expansion will result in many negative results. To solve these problems, the system and the exchange of information about the links between systems should define standards. IEC (International Electrotechnical Commission) power to solve these problems in the field of the Common Information Model (Common Information Model, CIM) standard (IEC61970, IEC61968) is defined as the transmission and distribution system integration and standardization for the exchange of information. In this paper, standardized system for building CIM-based distribution automation system should describe the process of building. In addition, the process of establishing a common information model needed (CIM) defined and associated services for a defined set of models is proposed in the standardization process.
Coordination of UPFC and Reactive Power Sources for Steady-state Voltage Control
Park, Ji-Ho ; Lee, Sang-Duk ; Jyung, Tae-Young ; Jeong, Ki-Seok ; Baek, Young-Sik ; Seo, Gyu-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 921~928
DOI : 10.5370/KIEE.2011.60.5.921
This paper presents a new method of local voltage control to achieve coordinative control among UPFC(Unified Power Flow Controller) and conventional reactive compensation equipments, such as switched-shunt and ULTC(Under-Load Tap Changing) transformer. Reactive power control has various difficult aspects to control because of difficulty of system analysis. Recently, the progress of power electronics technologies has lead to commercial availability of several FACTS(Flexible AC Transmission System) devices. The UPFC(Unified Power Flow Controller) simultaneously allows the independent control of active and reactive power flows as well as control of the voltage profile. When conventional reactive power sources and UPFC are used to control system voltage, the UPFC reacts to the voltage deviation faster than the conventional reactive power sources. Keeping reactive power reserve in an UPFC during steady-state operation is always needed to provide reactive power requirements during emergencies. Therefore, coordination control among UPFC and conventional reactive power sources is needed. This paper describe the method to keep or control the voltage of power system of local area and to manege reactive power reserve using PSS/E with Python. The result of simulation shows that the proposed method can control the local bus voltage within the given voltage limit and manege reactive power reserve.
Generator Scheduling Considering System`s Reliability and Demand Response
Kwag, Hyung-Geun ; Kim, Jin-O ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 929~935
DOI : 10.5370/KIEE.2011.60.5.929
Customers hardly change to electric prices in old days because electricity is essential commodity, while demand changes with price after deregulation. It`s explained by price-based demand response with demand-elasticity matrix. Also all of the customers have had identical demand-price elasticity matrix till now. But in a practical power system, various customers are present with taking a variety of demand-price elasticity. Therefore this paper proposes demand-price sensitivity to represent different demand-price elasticity. Also as proposing demand-reliability sensitivity, it is modeling various customers` characteristics to reliability. And then this paper calculates total expected interruption cost of customer from the customer interruption cost and the demand-reliability sensitivity. A total expected interruption cost of system is shown as opportunity cost of a generation cost.
Development of Generator Reactive Capability Test Method in Generation Stations
Shin, Man-Su ; Jeong, Tae-Won ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 936~941
DOI : 10.5370/KIEE.2011.60.5.936
Generation cooperations have focused on active power directly related to economic value. So, utility cooperation have taken expense to stabilize power system, although generator has responded quickly with variation of power system voltage and is controlled at real time. As a reactive power source, it is necessary for generator`s capabilities to be verified. But domestic generators scarcely have been tested and operated to reactive power capability. In case of power system fault, operators would not quickly take a follow-up actions about reactive power disturbance. Therefore generator reactive power capability verification strategy must be developed, several generators is tested as examples since 2004. This paper is extracted from the test results.
Quasi-3D analysis of Axial Flux Permanent Magnet Rotating Machines using Space Harmonic Methods
Choi, Jang-Young ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 942~948
DOI : 10.5370/KIEE.2011.60.5.942
This paper deals with characteristic analysis of axial flux permanent magnet (AFPM) machines with axially magnetized PM rotor using quasi-3-D analysis modeling. On the basis of magnetic vector potential and a two-dimensional (2-D) polar-coordinate system, the magnetic field solutions due to various PM rotors are obtained. In particular, 3-D problem, that is, the reduction of magnetic fields near outer and inner radius of the PM is solved by introducing a special function for radial position. And then, the analytical solutions for back-emf and torque are also derived from magnetic field solutions. The predictions are shown in good agreement with those obtained from 3-D finite element analyses (FEA). Finally, it can be judged that analytical solutions for electromagnetic quantities presented in this paper are very useful for the AFPM machines in terms of following items : initial design, sensitivity analysis with design parameters, and estimation of control parameters.
Study on Machine Characteristics in Interior Permanent Magnet Synchronous Motor According to Pole/Slot Combinations with Radial Vibration Force Consideration
Fang, Liang ; Lee, Su-Jin ; Lee, Byeong-Hwa ; Hong, Jung-Pyo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 949~954
DOI : 10.5370/KIEE.2011.60.5.949
This paper presents a comparative study on motor characteristics with specific consideration of radial vibration force in interior permanent magnet synchronous motors (IPMSM) according to pole/slot combinations. Three IPMSM models, 16-pole/15-slot design, 16-pole/18-slot design and 16-pole/24-slot design are built, in which 16-pole/15-slot and 16-pole/18-slot designs provide high winding factor and 16-pole/24-slot design is known as a general pole/slot combination. By coupling finite element analysis (FEA) with equivalent circuit method, motor characteristics, back electro-motive force (Back-EMF), inductances, cogging torque, etc. as well as machine output performances are analyzed and compared. The radial vibration force (RVF) distribution in air gap causing stator vibration and noise is interested. It is expected that this study help with appropriate choice of pole/slot combination in IPMSM design.
Analysis and Design of high-efficiency Permanent Magnet Synchronous Motor/Generator for Renewable Energy Application
You, Dae-Joon ; Kim, Il-Jung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 955~964
DOI : 10.5370/KIEE.2011.60.5.955
In renewable energy system such as flywheel energy storage system, wind power and solar power, the motor/generator is the important key for offering the electric energy to the electric loads. For example, the heavy and large flywheel is rotated by electromagnetic torque of pemanent magnet synchronous motor (PMSM) and, in case of a breakdown of electric current, the PMSM used as generator supplies electric energy for the various electric utilities using mechanical rotation energy of the flywheel. Thus, design of a motor/generator should be performed in effort to reduce cogging torque and electromagnetic loss for high efficiency. In our paper, a slotless permanent magnet synchronous motor/generator (SPMSM/G) with output power 15kW at the rotor speed 18000rpm is designed from electromagnetic analysis and dynamic performance analysis. In analytical approach, design parameters such as back electro-motive force (back EMF), inductance and electromagnetic torque are derived from analytical method which is one of the electromagnetic analysis method. And using the design parameters, this paper deal with system design considering the driving characteristics and electric load in required power. Finally, the analytical results are verified by the experiment and finite element method (FEM).
Characteristics Analysis in A Pole Changing Memory Motor Using Coupled FEM & Preisach Modeling
Lee, Seung-Chul ; Lee, Jung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 965~970
DOI : 10.5370/KIEE.2011.60.5.965
This paper deals with the PM performance evaluations in a pole changing memory motor (PCMM) using a coupled transient finite element method (FEM) and Preisach modeling, which is presented to analyze the magnetic characteristics of permanent magnets. The focus of this paper is the characteristics evaluation relative to magnetizing direction and the pole number of machine on re-demagnetization condition in a pole changing memory motor.
A Test System of Valve and Poles for Large Scale Inverter using Resonant Circuit
Han, Young-Seong ; Chung, Chung-Choo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 971~976
DOI : 10.5370/KIEE.2011.60.5.971
This paper proposes a test system for a valve and poles building blocks used for large scale inverters such as STATCOM, SSSC, UPFC and VSC HVDC. Power semiconductors in the valve are normally connected in series to withstand switching voltage much larger than the voltage rating of a single power semiconductor. Therefore, there is a need to verify if the dynamic voltage sharing during switching in a valve is satisfactory. In this paper, we propose a test system that provides the necessary test condition: voltage and current in the valve using resonant circuits. A test scheme for a single phase inverter consisting two poles is also proposed. The performance of the inverter pole has to be verified at the factory test, before the system is installed at the site to secure the reliability of the system. The proposed scheme makes it possible to confirm if the pole can withstand voltage and current switching condition and handle loss.
Speed Control of Permanent Magnet Synchronous Motors using an Adaptive Controller
Jung, Jin-Woo ; Kim, Tae-Heoung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 977~983
DOI : 10.5370/KIEE.2011.60.5.977
This paper proposes a new adaptive speed controller to achieve a robust speed control of a permanent magnet synchronous motor(PMSM). The proposed adaptive regulator does not require any information on the motor parameter and load torque values, so it is very insensitive to model parameter and load torque variations. Also, the stability of the proposed adaptive control system is proven. To validate the robustness of the proposed adaptive speed controller, both simulation and experimental results are provided under motor parameter and load torque variations. It is clearly demonstrated that the proposed adaptive regulator can accurately control the speed of permanent magnet synchronous motors.
Analysis on the Chemical and Electrical Characteristic of Vegetable oil by Accelerated Aging
Choi, Sun-Ho ; Jeong, Jung-Il ; Huh, Chang-Su ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 984~989
DOI : 10.5370/KIEE.2011.60.5.984
Electrical insulation is one of the most important part in a high voltage apparatus. Recently, researchers are interested in the environmental friendly vegetable oil from environmental viewpoint. Accelerated aging transformer insulating material in vegetable oil was compared to that of mineral oil. Accelerated aging oil samples produced in the oven at
for 500, 1000, 1500, 2000hours. And Real transformer insulation oils samples of vegetable oil and mineral oil were aged by thermal cycles repeating from
. Samples were analyzed at 42, 63, 93, 143, 190, 240, 300 cycles. The mineral and vegetable insulating oils were investigated for breakdown voltage, water content, total acid number, viscosity, volume resistivity, insulating paper and oil permittivity, and dissolved gas analyses. The breakdown voltage of the vegetable insulating oil is higher than that found for the mineral oil; the accelerated aging progress decreased the breakdown voltage. The vegetable oil had a higher water saturation than the mineral oil; the vegetable oil has the superior water characteristics and breakdown voltage. And high viscosity of vegetable oil, care has to be taken, especially when designing the cooling system for a large transformer.
A Study on the Structural Properties of Epoxy Based Nanocomposites
Lee, Sang-Heon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 990~992
DOI : 10.5370/KIEE.2011.60.5.990
In this paper, epoxy nanocomposites, focusing on the electrical properties of the composites to understand controllers, circuit breakers, bushings and power to apply to the modified instrument was carried out basic research. Composed of composites of this study to develop a power unit to control the dispersion synthesis technology is essential electrical appliances such as electrical properties analysis techniques will also need basic research skills and experience accumulated in this study, several areas of applied technology. In this study, promotion and application of nano-composite material application technology power devices than conventional insulation materials and excellent electrical properties and easy synthesis and high reliability are expected to be practical if you expect that its effects are very large. Therefore, this study has very importance.
Design of Erase Waveform for Stabilizing Reset Discharge in Mid-gap AC Plasma Display Panels
Yoon, Su-Han ; Seo, Jeong-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 993~998
DOI : 10.5370/KIEE.2011.60.5.993
In this paper we suggest new criteria for the classification of the electrode gap between common and scan electrodes. The electrode gap is categorized as a short, middle, and long gap according to the criteria. Among these structures, we focus on the erase waveform of a mid-gap structure. we report an unstable discharge arising from the erase ramp period in a mid-gap structure. Based on the Vt close curve, we analyze the unstable discharge at various conditions. Our analysis reveals that the unstable discharge is ignited between surface electrodes and caused by un-erased wall charges accumulated on the outer edges of electrodes. By reducing the voltage level of the last sustain pulse, the problem is solved.
An Analysis on the Overvoltage in Gas Insulated Transmission Lines with EMTP/ATPDraw
Park, Hung-Sok ; Han, Sang-Ok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 999~1004
DOI : 10.5370/KIEE.2011.60.5.999
Nowadays, it is becoming difficult to secure a transmission line route when a new transmission line is constructed due to social environment and resident complaints. As existing urban areas are expanded and new cities are constructed, the necessity of high-capacity underground power transmission has been increasing because of load concentration in downtown areas. In North America, Europe and Japan, the research has been carried out for 2nd generation gas insulated transmission lines(GIL) which is more environmentally friendly and economical compared to previous GILs. The new GILs have been applied to real power systems from early 2000s. In South Korea, GIL is being considered as a possible solution for replacing 345kV high-capacity overhead transmission lines with underground transmission ones, so KEPCO is planning to develop and apply a new 362kV rated GIL underground transmission lines instead of overhead transmission lines. In this paper, the overvoltage generated at the combined transmission line adapting GIL was reviewed using EMTP.
A Study on the Lightning Impulse Dielectric Characteristics of Air for the Development of Air-Insulated High Voltage Apparatuses
Nam, Seok-Ho ; Kang, Hyoung-Ku ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1005~1010
DOI : 10.5370/KIEE.2011.60.5.1005
The accidents caused by dielectric instability have been increasing in power grid. It is important to enhance the dielectric reliability of a high voltage apparatus to reduce the damage from electrical hazards. To develop an electrically reliable high voltage apparatus, the experimental study on the electrical breakdown field strength is indispensable, as well as theoretical approach. In this paper, the lightning impulse breakdown characteristics considering utilization factors are studied for the establishment of insulation design criteria of an high voltage apparatus. The utilization factors are represented as the ratio of mean electric field to maximum electric field. Dielectric experiments are performed by using several kinds of sphere-plane electrode systems made of stainless steel. As a result, it is found that dielectric characteristics are affected by not only maximum electric field intensity but also utilization factors of electrode systems. The results are expected to be applicable to designing the air-insulated high voltage apparatuses.
Design of a Surface-Mounted PMSM Current Controller Using Uncertainty Estimation with a PI Observer
Kim, In-Hyuk ; Choi, Dae-Sik ; Son, Young-Ik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1011~1016
DOI : 10.5370/KIEE.2011.60.5.1011
This paper presents a robust current controller for a surface-mounted permanent magnet synchronous motor(SPMSM) by using a PI observer. The decoupling PI(proportional-integral) controller combined with an additional feed-forward compensation has been used for the current controller. The classical feed-forward compensation using velocity information and system parameters is not expected to achieve a robust performance against parameter uncertainties. This paper has adopted a PI observer for the feed-forward compensation to cope with parameter uncertainties without using velocity information. A simple PI observer has been designed to compensate the disturbances that represent velocity coupled terms and parameter uncertainties. Experimental results as well as computer simulations with 630W SPMSM confirm that the proposed approach can deal with the effects of the disturbance and improve the control performance.
The Reduction of Generator Output Calculation by Using 6σ Method on Steam Turbine Simulator in a Nuclear Power Plant
Choi, In-Kyu ; Kim, Jong-An ; Park, Doo-Yong ; Woo, Joo-Hee ; Shin, Man-Su ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1017~1022
DOI : 10.5370/KIEE.2011.60.5.1017
This paper describes the improvement of the calculation by using
method on steam turbine simulator in a nuclear power plant. The simulator is essential to not only verification and validation of control logic but also making sure of control constants in upgrading the long time used control system into the new one. And the dynamic model is a key point in that simulator. The model used during the retrofit period of the turbine controller in Kori Nuclear Power Plant makes difference in calculating generator output and control valve positions. That is because such operating data as the main steam pressure, the main steam temperature and control valve positions of Yongkwang #3 are different from those of Kori #4. Therefore, the model parameters must be tuned by using actual operating data for the high fidelity of simulator in calculating the dynamic characteristic of the model. This paper describes that the
method is used in improvement of precision of generator output calculation in the steam turbine model of the simulator.
Reduction of Control Areas for Geometric Image Correction
Lee, Wan-Young ; Park, Tae-Hyoung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1023~1029
DOI : 10.5370/KIEE.2011.60.5.1023
In the industrial vision systems, image correction has great influence on the overall performance of measurement or inspection. The overall area of distorted image is usually splitted into small control areas, and each area is corrected by its control points. The performance of correction methods using control points can be improved by reduction of control areas because the computational time and memory highly depend on the number of control areas. We develop a merging algorithm that reduces control areas and preserves the correction accuracy. The algorithm merges the splitted control areas by use of quad tree method. Experimental results are presented to verify the usefulness of the proposed method.
Development of Haptic Glove for Remote Control
Hwang, Yo-Seop ; Lee, Jang-Myung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1030~1035
DOI : 10.5370/KIEE.2011.60.5.1030
The remote control of mobile robot is widely used to perform dangerous and complex tasks such as underwater exploration and cleaning of nuclear reactor. For this purpose, the obstacle avoidance process will proceed to ensure a safe drive. In this paper, we tested that mobile robot drive in which replaced a pipe with a box. After we measured the distance around the obstacle through a sensor of robot, we got the information that changed haptic force from the distance of the obstacle.
Development of Error-Corrector Control Algorithm for Automatic Error Detection and Correction on Space Memory Modules
Kwak, Seong-Woo ; Yang, Jung-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1036~1042
DOI : 10.5370/KIEE.2011.60.5.1036
This paper presents an algorithm that conducts automatic memory scrubbing operated by dedicated hardwares. The proposed algorithm is designed so that it can scrub entire memory in a given scrub period, while minimally affecting the execution of flight softwares. The scrub controller is constructed in a form of state machines, which have two execution modes - normal mode and burst mode. The deadline event generator and period tick generator are designed in a separate way to support the behavior of the scrub controller. The proposed controller is implemented in VHDL code to validate its applicability. A simple version of the controller is also applied to mass memory modules used in STSAT-3.
A Test Vector Reordering for Switching Activity Reduction During Test Operation Considering Fanout
Lee, Jae-Hoon ; Baek, Chul-Ki ; Kim, In-Soo ; Min, Hyoung-Bok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1043~1048
DOI : 10.5370/KIEE.2011.60.5.1043
Test vector reordering is a very effective way to reduce power consumption during test application. But, it is time-consuming and complicated processes, and it does not consider internal circuit structure, which may limit the effectiveness. In this paper, we order test vectors using fanout count of primary inputs that consider the internal circuit structure, which may reduce the switching activity. Then, we reorder test test vectors again by using Hamming distance between test vectors. We proposed FOVO algorithm to perform these two ideas. FOVO is an effective way to reduce power consumption during test application. The algorithm is applied to benchmark circuits and we get an average of 3.5% or more reduction of the power consumption.
Analysis of Color Information by Photo Diode Sensor
Kim, Ji-Sun ; Jung, Gu-In ; Lim, Sung-Hwan ; Lee, Young-Jae ; Lee, Pil-Jae ; Lee, Jeong-Hwan ; Kim, Kyung-Seop ; Jun, Jae-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1049~1054
DOI : 10.5370/KIEE.2011.60.5.1049
Color is discerned due to the reflectance of object and its hue is determined by the Ratio of RGB spectrum. The aim of this study is to evaluate the Color information using by the optical system in terms of convenience and simplicity. Firstly, the differential Ratio of RGB is evaluated by photodiode Sensor which achieves a high efficiency with quick tranducer output. To extract the information of RGB Ratio, light emitting diode is built in Color sensing system with photodiode. Our proposed method is very economical, simple, and convenient. Our results can be applied to confirm the accurate information of Color in the research environments and commercial purposes. Thus RGB information can be determined subjectively and thus, the inherent characteristic of Color will be revealed precisely and its related features can be resolved in a real time mode.
A Study on Design Parameters for Ready-made Ear Shell of Hearing Aids
Urtnasan, Erdenebayar ; Jeon, Yu-Yong ; Park, Gyu-Seok ; Song, Young-Rok ; Lee, Sang-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1055~1061
DOI : 10.5370/KIEE.2011.60.5.1055
In this study, main parameters: aperture, first bend and second bend which express a structure of ear canal are extracted in order to modeling and manufacture the ready-made ear shells of hearing aids. The proposed parameter extraction method consists of 2 important algorithms, aperture detection and feature detection. In the aperture detection algorithm, aperture of 3-D scanned virtual ear impression and parameters relating to ear shell of hearing aid are determined. The feature detection algorithm detects first bend, second bend, and related parameters. Through these two algorithms, parameters for aperture, first bend, and second bend are extracted to model the ready-made ear shell of hearing aid. The values of these extracted parameters from 36 people`s right ear impression are analyzed and measured statistically. As a result of the analysis, it has been found that it is possible to classify ready-made ear shell parameters by age and size. The ready-made ear shell parameters are classified 3-size for 20 years old and 2-size for 60 years olde. Using 3D rhino program, virtual ready-made ear shell is reconstructed by parameters of every type, and simulated to model it. A final product was produced by transferring simulation result with rapid prototyping system. The modeled ready-made ear shell is evaluated with the objective and subjective method. Objective method is the comparison volume ratio and overlapped volume ratio of ear impression from randomly chosen 18 people and ready-made ear shell. And subjective method is that the final product of ready-made ear shell is used by users and the satisfaction number drawn from well fitting and comfortable testing was evaluated. In the result of the evaluation, it has been found that volume ration is 70%, big and middle size ready-made ear shell products are possible, and the satisfaction number is high.
A Study on the Method of Performance Qualification Test for GIL
Park, Hung-Sok ; Han, Sang-Ok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1062~1067
DOI : 10.5370/KIEE.2011.60.5.1062
As the expension of metropolis and increasing of housing site, GIL(Gas Insulated Line) comes to the fore as an alternative to overhead transmission line avoided by local resident. The certification and experimental test for the GIL is now in progress in under ground test lab, Go-chang. For the test, we propose a method of PQ(pre-qualification) test which is essential for development and field application in this paper. The test following this method take about 200 days or 300 days under the circumstances.
Study on Development of the Isolation Resistance Measurement System for Hydrogen Fuel Cell Vehicle
Lee, Ki-Yeon ; Kim, Dong-Ook ; Moon, Hyun-Wook ; Kim, Hyang-Kon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1068~1072
DOI : 10.5370/KIEE.2011.60.5.1068
Hydrogen Fuel Cell Vehicle(HFCV) is system that uses electrical energy of fuel cell stack to main power source, which is different system with other vehicles that use high-voltage, large-current. Isolation performance of this system which is connected with electrical fire and electrical shock is important point. Isolation resistance of electric installation is divided according to working voltage, it follows criterion more than
/VAC) about system operation voltage in a hydrogen fuel cell vehicle. Although measurement of isolation resistance in a hydrogen fuel cell vehicle is two methods, it uses mainly measurement by megger. However, the present isolation resistance measurement system that is optimized to use in electrical facilities is unsuitable for isolation performance estimation of a hydrogen fuel cell vehicle because of limit of maximum short current and difference of measurement resolution. Therefore, this research developed the isolation resistance measurement system so that may be suitable in isolation performance estimation of a hydrogen fuel cell vehicle, verified isolation performance about known resistance by performance verification of laboratory level about developed system, and executed performance verification through comparing results of developed system by performance verification of vehicle level with ones of existing megger. Developed system is judged to aid estimation and upgrade of isolation performance in a hydrogen fuel cell vehicle hereafter.
Analysis of the Recovery Behavior of SFCL According to Reclosing Operation
Ha, Kyoung-Hun ; Cho, Yong-Sun ; Kim, Deog-Goo ; Choi, Hyo-Sang ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 5, 2011, Pages 1073~1077
DOI : 10.5370/KIEE.2011.60.5.1073
The breaking capacity of circuit breakers could be no more increased in the electric power system. This is because the fault current increases due to continuous increases in electric power demand and facilities. To solve the problem, it is necessary to come up with an alternative. The superconducting fault current limiter (SFCL) has received an attention among various alternatives. The SFCL effectively reduce a fault current in cooperation with a power circuit breaker. A various types of the SFCL are suggested and a study on them have been progressed. As a result of it, the SFCL can be applyed to the electric power system in the near future. But, a study on recovery behaviors of the SFCL is not enough for applying to the electric power system. If the superconducting elements do not completely recover to the superconducting state after fault operation, it might be a breakdown of the superconducting elements due to heavy power burden and it gives an bad influence on the working of other electric devices. Additionally, the distribution power system has reclosing operation such as open-0.3sec-closed/open-3min-closed/open procedure. So we need to study more about improvement of the recovery behaviors of the SFCL. In this paper, we analyzed the recovery behaviors of a flux-coupling type SFCL according to reclosing operation when a single line-to-ground fault occurred and we compared recovery behaviors of the SFCL with and without a neutral line between secondary reactors and superconducting elements. Also, the flux-coupling type SFCL has advantageous for increases of capacity by controlling the variation in turn ratios between two reactors. Consequently, when the number of turns of the secondary reactors increased, the power burden of the superconducting elements was bigger due to the increase of impedances of the secondary reactors. To distribute the power burden, two superconducting elements connected in series and the balanced quenching of the superconducting elements was induced by connecting a neutral line.