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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 57, Issue 12 - Dec 2008
Volume 57, Issue 11 - Nov 2008
Volume 57, Issue 10 - Oct 2008
Volume 57, Issue 9 - Sep 2008
Volume 57, Issue 8 - Aug 2008
Volume 57, Issue 7 - Jul 2008
Volume 57, Issue 6 - Jun 2008
Volume 57, Issue 5 - May 2008
Volume 57, Issue 4 - Apr 2008
Volume 57, Issue 3 - Mar 2008
Volume 57, Issue 2 - Feb 2008
Volume 57, Issue 1 - Jan 2008
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A Numerical Algorithm for Fault Location Estimation Considering Long-Transmission Line
Kim, Byeong-Man ; Chae, Myeong-Suk ; Kang, Yong-Cheol ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2139~2146
This paper presents a numerical algorithm for fault location estimation which used to data from both end of the transmission line. The proposed algorithm is also based on the synchronized voltage and current phasor measured from the PMUs(Phasor Measurement Units) in the time-domain. This paper has separated from two part of with/without shunt capacitance(short/long distance). Most fault was arc one-ground fault which is 75% over . so most study focused with it. In this paper, the numerical algorithm has calculated to distance for ground fault and line-line fault. In this paper, the algorithm is given with/without shunt capacitance using II parameter line model, simple impedance model and estimated using DFT(Discrete Fourier Transform) and the LES(Least Error Squares Method). To verify the validity of the proposed algorithm, the EMTP(Electro- Magnetic Transient Program) and MATLAB did used.
Estimation of the Circulating Currents in the Parallel Operation of Transformers
Kang, Yong-Cheol ; Lee, Mi-Sun ; Lee, Byung-Eun ; Choi, Jae-Sun ; Jang, Sung-Il ; Kim, Yong-Gyun ; Lyu, Young-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2147~2152
This paper proposes an algorithm to estimate the circulating currents in the transformers in parallel in an ultra high voltage system. For the Y-Y-
transformers operated in parallel, there exist two kinds of the circulating currents i.e. one is between the tanks and the other between the banks of the delta side. As the former is 90 deg out of phase of the load current, it is estimated by decomposing the line current into the component 90 deg out of phase of the load current in the frequency domain. The latter is estimated in the time domain from applying the Kirchhoff's voltage law on the delta winding which gives a first-order differential equation in terms of the delta winding currents. To estimate the circulating currents between the tanks, the performance of the proposed algorithm is investigated when the impedances of the two transformer tanks are different or the taps of the on-load tap changer of the transformers are mismatched temporarily. To estimate the circulating currents between the banks, the performance of the proposed algorithm is also examined under magnetic inrush and over-excitation. Test results indicate that the algorithm can estimate the two kinds of the circulating currents successfully.
Probabilistic Production Cost Credit Evaluation of Wind Turbine Generators
Park, Jeong-Je ; Wu, Liang ; Choi, Jae-Seok ; Cha, Jun-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2153~2160
This paper develops an algorithm for probabilistic production cost credit evaluation of wind turbine generators(WTG) with multi-state. Renewable energy resources such as wind, wave, solar, micro hydro, tidal and biomass etc. are becoming importance stage by stage because of considering effect of the environment. Wind energy is one of the most successful sources of renewable energy for the production of electrical energy. Case study demonstrates that the wind speed credit in view point of economics can be assessed by using the proposed methodology.
Voltage THD Mitigation of Power Distribution System using Z-Source Active Power Filter with a Fuel Cells Source
Jung, Young-Gook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2161~2166
This paper deals with a Z-source active power filter(Z-AFU) for mitigation voltage THD(total harmonic distortion) due to voltage harmonic propagation(amplification) in 6.6kv power distribution system. Bus voltage harmonic signal is detected by 60Hz butterworth BPF(band pass filter). As an ESS(energy storage system) of the proposed system, PEM fuel cells(Ballard NEXA, 1.2kw) is employed. Test results based on PSIM(power electronics simulation tool) validate the proposed approach.
Islanding Detection Based on Complex Power at the Intertie
Kang, Yong-Cheol ; Cha, Sun-Hee ; Jang, Sung-Il ; Kang, Hae-Gweon ; Kim, Yong-Gyun ; Park, Goon-Cherl ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2167~2172
A large scale embedded generator or a micro-grid is usually interconnected to the grid through the dedicated line. Immediately after the removal of the grid supply, it must be disconnected and remain disconnected until the normal grid supplies are restored. This paper proposes an islanding detection algorithm based on complex power at the intertie. Complex power at the intertie delivered to the grid has a value depending on power flow during normal operation. When loss of mains occurs, complex power at the intertie moves to a value depending on the parameters of the dedicated line. The performance of the proposed algorithm was investigated under various operating and fault conditions. The proposed algorithm can detect an islanding operation even if no power is exchanged prior to loss of mains and discriminate the fault condition from islanding.
Protection for DFIG using the d-q Equivalent Circuit
Kang, Yong-Cheol ; Lee, Ji-Hoon ; Kang, Hae-Gweon ; Jang, Sung-Il ; Kim, Yong-Gyun ; Park, Goon-Cherl ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2173~2178
A doubly-fed induction generator(DFIG) system has been widely used in the modem wind turbines due to variable-speed operation, high efficiency and small converter size. It is well known that an inter-turn fault of a generator is very difficult to be detected. The DFIG system uses a wound rotor induction machine so that the magnetizing current of the generator can be fed from both the stator and the rotor. This paper proposes a protection algorithm for a DFIG using the d-q equivalent circuit in the time domain. In the case of a DFIG, the voltages and currents of the rotor side as well as the voltages and currents of the stator are available. The proposed algorithm estimates the instantaneous(i.e., converted into the stationary frame) induced voltages from the rotor and the stator sides. If the difference between the two estimated induced voltages exceeds the threshold, the proposed algorithm detects the inter-turn fault. The algorithm can detect a inter-turn fault of a winding. The performance of the proposed algorithm is validated using a PSCAD/EMTDC simulator under inter-turn fault conditions and normal operating conditions such as an external fault and the change of the wind speed.
A Study on the Optimal Investment Method for Distribution Systems Interconnected with Dispersed Generations
Rho, Dae-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2179~2185
This paper deals with the optimal investment method for distribution facilities, based on the analytical approach for the reliability assessment in distribution systems interconnected with new dispersed generations. The existing approach can estimate the expected reliability performance of distribution systems by a direct assessment of the configuration of the systems using the reliability indexes such as NDP(Non-Delivery Power) and NDE(Non-Delivery Energy). The indexes can only consider the number and configuration of the load, but can not consider the characteristics of the load which is the one of the most important factor in the investment cost for the distribution systems. Therefore, this paper presents the new performance indexes for the investment of the distribution facilities considering both the expected interruption cost for the load section and the operation characteristics of dispersed generations. The results from a case study show that the proposed methods can be a practical tool for the voltage management in distribution systems including dispersed sources.
A Study on the Design of Single Phase LSPM Considering the Irreversible Demagnetization of Permanent Magnet
Jung, Dae-Sung ; Go, Sung-Chul ; Park, Hyun-June ; Kwon, Sam-Young ; Lee, Hyung-Woo ; Lee, Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2186~2193
The growth on consideration of energy savings and motor efficiency has caused the LSPM(Line Start Permanent Magnet Motor) to be focused as a substitute for conventional induction motors. A Line start permanent magnet motor able to be driven at synchronous speed is designed based on a single phase induction motor in this paper. The single phase LSPM is identical to the induction motor except a permanent magnet is installed in the rotor. As the permanent magnet influences the characteristics of both transient state and steady state, a design considering both starting and synchronization conditions was used. In this paper, by adopting DOE, a single phase motor has been designed showing high power and smooth start. Also, optimal model is selected by weighting function. And the characteristics demagnetization are analyzed according to the variation of magnet shape. Finally, to verify the design results, a prototype was measured.
The Analysis of Transverse Edge Effect of Linear Induction Motor by using Finite Element Method
Lee, Sung-Gu ; Bae, Jae-Nam ; Lee, Hyung-Woo ; Park, Hyun-June ; Kwon, Sam-Young ; Lee, Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2194~2198
In this paper, the construction of secondary reaction plate is analyzed by 3-D Finite Element Method(3-D FEM) to consider the influence of its variation on the transverse edge effect of LIM. The effective 3-D analysis model for considering the transverse edge effect caused by the finite widths of the primary and the secondary is proposed. The simple method measuring the transverse edge effect by using the patterns of currents induced in the secondary reaction plate is also proposed. With this effective analysis method, various models of secondary reaction plate with overhang and cap has been analyzed to consider the relationship between the construction of secondary reaction plate and the transverse edge effect of LIM.
Emission Characteristics at High Voltage Equipments in use-phase Stage
Park, Jung-Ju ; Cha, Yeun-Haeng ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2199~2201
) is a gaseous dielectric used in high voltage electrical equipment such as an insultor or arc quenching medium in the transmission and distribution of electricity. however,
is one of the greenhouse gases(GHG) with a global warming potential that is 23,900 times greater than that of carbon dioxide(
). for this reason,
emissions in electric equipment shall be controlled to reduce GHG and improve cost-effective use of
for economical benefits. Until recently there has not been any investigation on
emission characteristics and inventory in Korea. To understand emission characteristics during the use-phase, the scope of this study was limited to the following closed pressure system equipment from 10 substations in Korea. This study highlights (1) the investigation of sampling/analysis methodology for
emissions in high voltage equipment, (2) the estimation of
emissions in the use-phase, and (3) the comparison between the emission ratio and the mass-balance applied to inventory study. According to this study, the majority of emissions were related to electric equipment nameplates and the rest of the emissions were related to the handling of
during operations. from this result, emission ratios estimated from this study were similar; GIS was 14% and GCB was 13%, as maintenance process conditions were the same as manual process conditions for both equipment.
A Design and Driving Characteristics of Novel Hybrid Pole Bearingless SRM
Lee, Dong-Hee ; Wang, Hui-Jun ; An, Young-Joo ; Ahn, Jin-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2202~2207
Bearingless SRM(Switched Reluctance Motor) is researched for high speed or special applications which can not use mechanical bearing such as bio pump. In this paper, a novel hybrid pole bearingless SRM is presented. The proposed hybrid pole bearingless SRM has salient poles for torque and suspending force production. Motor torque is controlled by the phase currents in torque pole windings, and the suspending force is controlled by suspending currents in four suspending windings for radial direction suspension. Because the proposed bearingless SRM has divided pole structure, mutual effects between torque current and suspending current are very lower than the conventional one's. From this structure, the number of power devices for power converter can be reduced for bearingless SRM driving. The proposed hybrid pole bearing less SRM is verified by the FEM analysis and experimental results.
Cost Reduction Design in Single-phase Line-start Permanent Magnet Motor
Lee, Byeong-Hwa ; Nam, Hyuk ; Lee, Jeong-Jong ; Fang, Liang ; Hong, Jung-Pyo ; Ha, Seung-Hyung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2208~2212
This paper deals with the cost reduction design of a single-phase line-start permanent magnet(LSPM) motor. Due to high cost of the permanent magnet(PM), cost reduction can be effectively achieved by reducing PM volume. Therefore, motor characteristics according to the PM volume are calculated by using d-q axis equivalent circuit analysis, and the characteristic map is made. In the characteristic map, maximum torque and efficiency are shown according to motor parameters such as back electromotive force(back emf) and inductances; back emf represents the PM volume. Minimum back emf and inductances satisfying output performance are determined in the characteristic map. Then, motor geometry based on the prototype motor is optimized to get the determined parameters using response surface methodology(RSM) and finite element method(FEM). Through the presented cost reduction design, total PM volume is reduced to 32% of prototype model.
A Study on Standards of Transformer Noise Level for Outdoor Substation
Koo, Kyo-Sun ; Kweon, Dong-Jin ; Kwak, Ju-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2213~2219
Customer complaints on noise from the power transformer have been increased because of their concerns on environment. In order to solve fundamental noise problem of the transformer, KEPCO and domestic transformer manufacturers are developing 55 dBA class low noise transformers. To check accordance of the noise abatement law, we study relation between transformer noise level and substation border noise level. We present 'noise level of the substation border' under operating conditions and transformer noise level change. We also present an appropriate noise level of the transformer that satisfy the noise abatement law for outdoor substations.
Accident Prevention Technology at a Level Crossing
Cho, Bong-Kwan ; Ryu, Sang-Hwan ; Hwang, Hyeon-Chyeol ; Jung, Jae-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2220~2227
The safety equipments of railway level crossing which are installed at intersections between roads and railway lines prevent level crossing accidents by informing all of the vehicles and pedestrians of approaching trains. The intelligent safety system for level crossing which employs information and communication technology has been developed in USA and Japan, etc. But, in Korea, the relevant research has not been performed. In this paper, we analyze the cause of railway level crossing accidents and the inherent problem of the existing safety equipments. Based on analyzed results, we design the intelligent safety system which prevent collision between a train and a vehicle. This system displays train approaching information in real-time at roadside warning devices, informs approaching train of the detected obstacle in crossing areas, and is interconnected with traffic signal to empty the crossing area before train comes. Especially, we present the video based obstacle detection algorithm and verify its performance with prototype H/W since the abrupt obstacles in crossing areas are the main cause of level crossing accidents. We identify that the presented scheme detects both pedestrian and vehicle with good performance.
Research on the Performance Test of System in Package Chips for the Digital Broadcasting Receiver
Kim, Jee-Gyun ; Lee, Heon-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2228~2233
This research paper aims to establish a test process of the AFE SiP chip. It measured the sensitivity, current consumption and power consumption both on the evaluation socket board and Catalyst load board. As a result, the sensitivity became deteriorated with an average of 0.2[dBm] at the channel 62 only, the current consumption increased to an average of 0.57[mA] and the power consumption increased to an average of 1.76[mW], But all characteristics incomes the tolerance of the measurement, it also keeps almost the same level. Therefore this design of the test process improved a valid design.
Approximate Equations and Sensitivity for Breakdown Voltages of Cylindrical PN Junctions in Power Semiconductor Devices
Yun, Jun-Ho ; Kim, Hae-Mi ; Seo, Hyeon-Seok ; Jo, Jung-Yol ; Choi, Yearn-Ik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2234~2237
Approximate equations for cylindrical breakdown voltages of planar pn junctions are proposed and verified. The equations show good agreement with the Baliga's results for
and with numerical results for
within 1% error. Sensitivity of the breakdown voltage with respect to the doping concentrations is successfully derived using the approximate equations. The sensitivity formula can be utilized in the area of tolerance design of power semiconductor devices.
Electrical and Optical Characteristics of Ceramic Metal Halide Lamp with Operating Electronic Ballast
Kim, Nam-Goon ; Yang, Jong-Kyung ; Lee, Joo-Hoo ; Jang, Hyeok-Jin ; Park, Dae-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2238~2243
The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp's properties. These properties translate into higher efficacy with better color rendering, stable color through lamp long life. Recently, due to an increase in the application of the ceramic metal-halide lamp, the study for the property etc. according to Ballast's driving scheme and the study for arc tube material, optimization of gas and so on are being proceeded to improve the property of the lamp. Especially, to control ceramic metal-halide lamp, the vigorous study and practical use with respect to Electronic Ballast, which has been improved in the disadvantages of the conventional Magnetic Ballast are made. In this paper, Electrical, optical and thermal characteristics are analyzed by comparing magnetic ballast with electronic ballast.
Optical Properties with Arc Tube Structure of Ceramic Metal Halide lamps
Lee, Joo-Hoo ; Yang, Jong-Kyung ; Kim, Nam-Goon ; Jang, Hyeok-Jin ; Park, Dae-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2244~2248
High intensity metal halide discharge lamp performance, specifically the generated luminous flux and light color content, depends critically on the arc tube design. Factors influencing the design and consequent lamp efficacy include : lamp size, geometry, arc tube composition, fill chemistry, electrode design and excitation modes. Shaping of Polycrystalline Alumina(PCA) can be realized by conventional ceramic processes. Several processes are applied nowadays. Well-known in the ceramic high pressure field for decades are the pressing and the extrusion method. Newly developed slurry and precious forming technologies give the one-body seamless tubes, which improve thickness uniformity and lighting performance. Now, we reported some optical properties with different arc tube structures of ceramic metal halide lamps.
The effect of RF electric fields from an atmospheric micro-plasma needle device on the death of cells
Yoon, Hyun-Jin ; Shon, Chae-Hwa ; Kim, Gyoo-Cheon ; Lee, Hae-June ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2249~2254
A non-thermal micron size plasma needle is applicable for medical treatment because it includes radicals, charged particles, ultraviolet emission, and strong electric fields. The electric fields around the plasma needle device driven by a radio frequency wave are investigated in order to calculate the power delivered to the cell. A commercial multi-physics code, CFD-ACE, was utilized for the calculation of electric fields for the optimization of the needle structure. The electric field and energy absorption profiles are presented with the variation of the device structure and the distance between the needle and tissues. The living tissues effectively absorb the radio frequency power from the plasma needle device with the covered pyrex structure.
Optimum Design Methodology of the Damped Oscillatory Impulse Current Generator Considering a Nonlinear Load
Chang, Sug-Hun ; Lee, Jae-Bok ; Shenderey, S.V. ; Myung, Sung-Ho ; Cho, Yuen-Gue ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2255~2262
This paper presents a design parameter calculation methodology and its realization to construction for the damped oscillatory impulse current generator(ICG) modelled as damping factor
. Matlab internal functions, "fzero" and "polyfit" are applied to find a which are solutions of second order nonlinear equation related with three wave parameters
. The calculation results for standard impulse current waveforms such as 4/10
show very good accuracy and this results make it possible to extend to generalization in the design of damped oscillatory lCG with any capacitor. 8/20
ICG based on the calculated design circuit parameters is fabricated in consideration of the nonlinear load(MOV) variation. Comparisons of the tested waveforms with the designed estimation show error within 10% for the waveform tolerance recommended in IEC 60060-1 and IEEE std. C62.45.
The Damage of Microcontroller Devices due to Coupling Effects under High Power Electromagnetic Wave by Magnetron
Hong, Joo-Il ; Hwang, Sun-Mook ; Huh, Chang-Su ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2263~2268
We investigated the malfunction and destruction characteristics of microcontroller devices under high power electromagnetic(HPEM) wave by magnetron. HPEM was rated at a microwave output of 0 to 1,000 W, at a frequency of 2,450
50 MHz and was radiated from the open-ended standard rectangular waveguide(WR-340) to free space. The influence of different reset-, clock-, data-, and power supply-line lengths has been tested. The variation of the line length was done with flat cables. The susceptibility of the tested microcontroller devices was in general much influenced by clock-, reset-, and power supply-line length, little influenced by data-line length. Further the line length was increased, the malfunction threshold was decreased as expected, because more energy couples to the devices. The surfaces of the destroyed microcontroller devices were removed and the chip conditions were investigated with microscope. The microscopic analysis of the damaged devices showed component and bondwire destructions such as breakthroughs and melting due to thermal effects. The obtained results are expected to provide fundamental data for interpreting the combined mechanism of microcontroller devices in an intentional microwave environment.
The Design and Fabrication of CMOS LNA through De-embedded Verification of the Spiral Inductor
Lee, Han-Young ; Yoo, Young-Kil ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2269~2275
This paper examined the simulation results after applying not only spiral inductor's 3D EM simulation but also de-embedding technique to reduce the pad's RF effects. When calculating standard deviation with measurement results not only the gain at 0.5GHz
4GHz but also noise figure at 1.8GHz
4GHz, the simulation results includes de-embedded inductor' model improved gain deviation by 0.171 and noise figure deviation by 0.151 than the results from simulation with foundry inductor equivalent circuit models.
Optical and Thermal Influence Analysis of High-power LED by MCPCB temperature
Lee, Seung-Min ; Yang, Jong-Kyung ; Jo, Ju-Ung ; Lee, Jong-Chan ; Park, Dae-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2276~2280
In this paper, we present thermal dependancy of LED package element by changing temperature of MCPCB for design high efficiency LED lamp, and confirmed influence of LED chip against temperature with analysis of thermal resistance and thermal capacitance. As increasing temperature, WPOs were decreased from 25 to 22.5 [%] and optical power were also decreased. that is decreased reason of optical power that forward voltage was declined by decrease of energy bandgap. Therefore optical power by temperature of MCPCB should consider to design lamp for street light and security light. Moreover, compensation from declined optical efficiency is demanded when LED package is composed. Also, thermal resistances from chip to metal PCB were decreased from 12.18 to 10.8[
] by changing temperature. Among the thermal resistances, the thermal resistance form chip to die attachment was decreased from 2.87 to 2.5[
] and was decreased 0.72[
] in Heat Slug by chaning temperature. Therefore, because of thermal resistance gap in chip and heat slug, reliability and endurance of high power LED affect by increasing non-radiative recombination in chip from heat.
Drowsiness-drive Perception System Using Vision
Joo, Young-Hoon ; Kim, Jin-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2281~2284
The purpose of this paper is to develope the drowsiness-drive perception system which judges drowsiness driving based on drivers' eye region using single vision system. To do this, first, we use the Haar-like feature and AdaBoost learning algorithm for detecting the features of the face region. And we measure the eye blinking frequency and eye closure duration from these feature data. And then, we propose the drowsiness-drive detection algorithm using the eye blinking frequency and eye closure duration. Finally, we have shown the effectiveness and feasibility of the proposed method through some experiments.
Unit Response Optimizer mode Design of Ultra Super Critical Coal-Fired Power Plant based on Fuzzy logic & Model Predictive Controller
Oh, Ki-Yong ; Kim, Ho-Yol ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2285~2290
Even though efficiency of coal-fired power plant is proportional to operating temperature, increasement of operating temperature is limited by a technological level of each power plant component. It is an alternative plan to increase operating pressure up to ultra super critical point for efficiency enhancement. It is difficult to control process of power plant in ultra super critical point because that point has highly nonlinear characteristics. In this paper, new control logic, Unit Response Optimizer Controller(URO Controller) which is based on Fuzzy logic and Model Predictive Controller, is introduced for better performance. Then its performance is tested and analyzed with design guideline.
A Clamping Force Estimation Method in Electric Parking Brake Systems
Jang, Min-Seok ; Lee, Young-Ok ; Lee, Won-Goo ; Lee, Choong-Woo ; Son, Young-Sup ; Chung, Chung-Choo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2291~2299
Hall effect force sensors have been used to measure clamping force in conventional Electric Parking Brake(EPB) systems. Estimation of clamping force without the sensors has drawn attentions due to mounting space limitations and cost issues. Removing the sensor requires the estimation of the initial contact point where the clamping force is effectively applied to the brake pads. In this paper, we propose how to estimate the initial contact point finding the relation between the angular velocity of an actuator and the initial contact point. For force estimation a look-up table is used as a function of the displacement of parking cable from the initial contact point. The proposed method is validated by experiments. From the experimental results we observe that the proposed method satisfies the specifications. The designed method is also able to estimate clamping force although parking cables are loosened and brake pads are worn out. Applying the proposed method enables manufacturing of low cost EPB systems.
An Accidental Position Detection Algorithm for High-Pressure Equipment using Microphone Array
Kim, Deuk-Kwon ; Han, Sun-Sin ; Ha, Hyun-Uk ; Lee, Jang-Myung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2300~2307
This study receives the noise transmitted in a constant audio frequency range through a microphone array in which the noise(like grease in a pan) occurs on the power supply line due to the troublesome partial discharge(arc). Then by going through a series of signal processing of removing noise, this study measures the distance and direction up to the noise caused by the troublesome partial discharge(arc) and monitors the result by displaying in the analog and digital method. After these, it determines the state of each size and judges the distance and direction of problematic part. When the signal sound transmitted by the signal source of bad insulator is received on each microphone, the signal comes only in the frequency range of 20 kHz by passing through the circuit of amplification and 6th low pass filter. Then, this signal is entered in a digital value of digital signal processing(TMS320F2812) through the 16-bit A/D conversion. By doing so, the sound distance, direction and coordinate of bad insulator can be detected by realizing the correlation method of detecting the arriving time difference occurring on each microphone and the algorithm of detecting maximum time difference.
Indoor Localization System for Field Robot System of Power Plant Facilities Surveillance
Jeong, Chang-Ki ; Lee, Jae-Kyung ; Park, Joon-Young ; Cho, Byung-Hak ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2308~2312
As power plant facilities are being deteriorated, their safety is getting more important, and more routine surveillance is being required. For this purpose, this paper presents an indoor localization system for field robot system which performs the surveillance of power plant facilities instead of human workers from the viewpoint of the workers' safety and work efficiency.
A Study on Partial Discharge Pattern Recognition Using Neuro-Fuzzy Techniques
Park, Keon-Jun ; Kim, Gil-Sung ; Oh, Sung-Kwun ; Choi, Won ; Kim, Jeong-Tae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2313~2321
In order to develop reliable on-site partial discharge(PD) pattern recognition algorithm, the fuzzy neural network based on fuzzy set(FNN) and the polynomial network pattern classifier based on fuzzy Inference(PNC) were investigated and designed. Using PD data measured from laboratory defect models, these algorithms were learned and tested. Considering on-site situation where it is not easy to obtain voltage phases in PRPDA(Phase Resolved Partial Discharge Analysis), the measured PD data were artificially changed with shifted voltage phases for the test of the proposed algorithms. As input vectors of the algorithms, PRPD data themselves were adopted instead of using statistical parameters such as skewness and kurtotis, to improve uncertainty of statistical parameters, even though the number of input vectors were considerably increased. Also, results of the proposed neuro-fuzzy algorithms were compared with that of conventional BP-NN(Back Propagation Neural Networks) algorithm using the same data. The FNN and PNC algorithms proposed in this study were appeared to have better performance than BP-NN algorithm.
Design of Optimized Fuzzy Cascade controller Based on Partical Swarm Optimization for Ball & Beam System
Jang, Han-Jong ; Oh, Sung-Kwun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2322~2329
In this study, we introduce the design methodology of an optimized fuzzy cascade controller with the aid of particle swarm optimization(PSO) for ball & beam system. The ball & beam system consists of servo motor, beam and ball, and remains mutually connected in line in itself. The ball & beam system determines the position of ball through the control of a servo motor. We introduce the fuzzy cascade controller scheme which consists of the outer(1st) controller and the inner(2nd) controller as two cascaded fuzzy controllers, and auto-tune the control parameters(scaling facrors) of each fuzzy controller using PSO. For a detailed comparative analysis from the viewpoint of the performance results and the design methodology, the proposed method for the ball & beam system which is realized by the fuzzy cascade controller based on PSO, is presented in comparison with the conventional PD cascade controller based on serial genetic alogritms.
Barcode Pattern Image Watermark Using Triplet
Park, Byung-Su ; Chu, Hyung-Suk ; An, Chong-Koo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2330~2335
In this paper, we proposed a robust watermark scheme for image based on the discrete wavelet transform. In the first, we use the triplet method for embedding and extraction of watermark. Triplet method uses relationship among the discrete wavelet coefficients at the same position in the three detail subband of image. In the second, we use barcode Pattern Image for watermark scheme. By using barcode Pattern Images, a user is able to make many kinds of own watermark. In the third, the proposed method for image watermark provides the invisiblility which the other user can not discriminate watermark from watermarked image. The advantage of the proposed method is visibility when we extracted watermark from the image. The corresponding experimental results show that the proposed method has performance of a robustness from the noise attack.
A Study on the Muscle Activity and Fatigue of Hand Muscle for the Presentation of Normative Data in Labor Environment
Kim, Kyoung-Hyun ; Lee, Ho-Yong ; Shin, Hwa-Young ; Jeong, Seong-Hun ; Kim, Sung-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2336~2344
In this paper, muscular activity and muscle fatigue of FDI(first dorsal interosseous muscle) and thenar muscle of hand was analyzed with surface EMG signal based on four kinds of attitudes(grip, tip, key and palmar) to measure grip strength and pinch strength after hand operation and rehabilitation treatment. The normative data are needed to interpret evaluation data to assess a patient's ability to return to labor environment. The preceding researchers proposed the standard data only by studying on maximum grip strength and the maximum pinch strength followed by each attitude of subjects' hands. But in this study, the muscle activity and muscle fatigue were considered under the various attitude to propose normative data. As a results, the muscle fatigue may be used only for presentation of normative data in labor environment.
Analysis of Relations Between Transmission Time of Therapeutic Ultrasound and Pulse Transit Time
Kim, Sung-Min ; Lee, Joo-Hwan ; Choi, Byeong-Cheol ; Jung, Whoi-Seong ; Bae, Ha-Suk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2345~2350
Recently, ultrasound is becoming a universal way of treatment when it comes to clinic. The thermal effect of therapeutic ultrasound can raise the temperature of tissue without damage and thus increases the flow rate, and this leads to the oxygen transportation velocity of peripheral tissue and ultimately facilitates the metabolism. The purpose of this research is analyzing relations between PTT and transmission time of therapeutic ultrasound, and in this study the PTT variation due to respective transmission time of ultrasound upon 17 normal persons was measured and as a result, it was observed that PTT increases as transmission time of therapeutic ultrasound
Development of an Measuring System for Pulse Wave Corresponding to Different Radial Artery Diameters Caused by Indentation
Lee, Jeon ; Woo, Young-Jae ; Jeon, Young-Ju ; Lee, Yu-Jung ; Kim, Jong-Yeol ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 12, 2008, Pages 2351~2357
Noninvasive radial artery pulse wave has been widely used not only for the pulse wave analysis(PWA) itself but also for assessment of arterial stiffness with estimated aortic pulse wave from peripheral pulse wave. However, it has been found that the deformation of pulse shape can be caused readily by changing measuring position, indentation pressure, and so on. So, in this study, we have developed a system which can measure radial pulse wave and skin displacement simultaneously while the indentation body goes down to occlude subject's radial artery. This system can be divided into a measuring apparatus part, an indentation control hardware part, a data acquisition part and a control and computation part. And, the measuring apparatus consists of an arm-rest, a step motor, an indentation body, a laser displacement sensor(LK-G30, Keyence Co.) and pulse wave sensor. Under load-free condition and radial artery loaded condition, the evaluation of developed system has been performed. From these results, we can conclude: 1) The developed system can control the indentation body quantitatively and the adopted laser displacement sensor shows linear output characteristic even with skin as a reflector. 2) This system can measure the pulse wave and the displacement of indentation body, that is, skin displacement simultaneously at each specific level of indentation body. 3) This system can provide the number of motor steps used to get down the indentation body, the measured skin displacement, the calculated indentation pressure, the calculated pulse pressure and the pulse waveform as well as the information generated by combining these with each others. 4) This system can reveal the relationship between the morphological changes of pulse wave and the estimated displacement of radial artery wall by indentation. Consequently, the developed system can furnish more abundant information on radial artery than previous diagnosis systems based on tonometric measurement. In further study, we expect to setup the standard measuring process and to concrete the algorithm for the estimation of radial artery's diameter and of displacement of radial artery's wall. Furthermore, with well designed clinical studies, we hope to turn out the usefulness of developed system in the field of cardiovascular system evaluation.