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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
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A Study On Measurement-based Load Modeling Using PSCAD/EMTDC
Lee, Kyung-Sang ; Park, Rae-Jun ; Song, Kyung-Bin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1079~1085
DOI : 10.5370/KIEE.2011.60.6.1079
To supply electrical power with high quality, the power system must be optimized in many ways such as planning, control and management. In order to optimize the power system, the analysis of the power system is necessary. The elements of the power system require an accurate model to analysis of the power system. The components of the power systems such as generators, transformers and transmission lines have been studied and researched a lot in their modeling and very sophisticated models have been proposed. However, in case of load in-depth studies on the exact model are required. In this paper, measurement-based load modeling method using real-time measured data is proposed in various methods to reflect the characteristics of the load. To prove the validity of the proposed method, PSCAD/EMTDC program is used to configure the power system and measurement data according to the various failures are used to study on load modeling.
Generation Rescheduling Priority using Transient Energy Margin Sensitivity
Kim, Kyu-Ho ; Kim, Soo-Nam ; Rhee, Sang-Bong ; Song, Kyung-Bin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1086~1090
DOI : 10.5370/KIEE.2011.60.6.1086
This paper presents a method to evaluate generation rescheduling priority using transient energy margin sensitivity for power system operation. A change in any of the functional parameters obviously causes a change in the energy margin. Especially the energy margin sensitivity is evaluated for change with respect to generation. For a given contingency, the energy margin is computed and the respective sensitivities are also computed. It is possible to rank the sensitivities and thereby determine the generators which will affect the energy margin most and hence affect the stability (instability) of the system. The sign of the sensitivity indicates the direction of change in generation for a given change in energy margin.
Carbon Emission Analysis Considering Demand Response Effect in TOU Program
Kim, Young-Hyun ; Kwag, Hyung-Geun ; Kim, Jin-O ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1091~1096
DOI : 10.5370/KIEE.2011.60.6.1091
Currently, the concern about the environment is the issue all over the world, and in particular, carbon emissions of the power plants will not be able to disregard from the respect of generation cost. This paper proposes DR (demand response) as a method of reducing carbon emissions and therefore, carbon emissions cost. There are a number of studies considering DR, and in this paper, the effect of DR is focused on the side of carbon emission reduction effect considering Time-Of-Use (TOU) program, which is one of the most important economic methods in DSM. Demand-price elasticity matrix is used in this paper to model and analyze DR effect. Carbon emissions is calculated by using the carbon emission coefficient provided by IPCC (Intergovernmental Panel on Climate Change), and generator`s input-output characteristic coefficients are also used to estimate carbon emission cost as well as the amount of carbon emissions. Case study is conducted on the RBTS IEEE with six buses. For the TOU program, it is assumed that parameters of time period partition consist of three time periods (peak, flat, off-peak time period).
Modeling Demand Response by Using Registration and Participation Information of Demand Resources
Kwag, Hyung-Geun ; Kim, Jin-O ; Shin, Dong-Joon ; Rhee, Chang-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1097~1102
DOI : 10.5370/KIEE.2011.60.6.1097
This paper proposes the registration information, the participation information for classifying demand resources participate in demand response program. Modeling demand resources from them, it evaluates values of demand resources. Specially assuming that ignore the loss in power system, they take a role as generation. This paper proposes how to evaluate demand resources` values. Case study shows that demand response operators schedule efficiently demand response program by using index of such as the registration information the participation information of demand resource.
A study on Development of Korean - Energy System Management Model for Effect Analysis of Integrated Demand Management
Kim, Yong-Ha ; Jo, Hyun-Mi ; Kim, Ui-Gyeong ; Yoo, Jeong-Hui ; Kim, Dong-Gun ; Woo, Sung-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1103~1111
DOI : 10.5370/KIEE.2011.60.6.1103
This paper is developed to Energy Balance Flow show the flow of total energy resource be used nationally. The Energy Balance Flow is applicable of demand management factor through the analysis of foreign energy model of supply and demand and energy statistic data in the country. This study is based on and developed to Energy system management model is able to appraisal efficient of energy cost cutting, CO2 emission reduction and Energy saving at the national level calculated effect reached amount of primary energy to change of energy flow followed application of demand side management factor is able to appraisal quantitatively at the total energy to model of demand and supply.
Study on the Dynamic Synchronizing Control of An Islanded Microgrid
Cho, Chang-Hee ; Jeon, Jin-Hong ; Kim, Jong-Yul ; Kwon, Soon-Man ; Kim, Sung-Shin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1112~1121
DOI : 10.5370/KIEE.2011.60.6.1112
A microgrid is an aggregation of multiple distributed generators (DGs) such as renewable energy sources, conventional generators, and energy storage systems that provide both electric power and thermal energy. Generally, a microgrid operates in parallel with the main grid. However, there are cases in which a microgrid operates in islanded mode, or in a disconnected state. Islanded microgrid can change its operational mode to grid-connected operation by reconnection to the grid, which is referred to as synchronization. Generally, a single machine simply synchronizes with the grid using a synchronizer. However, the synchronization of microgrid that operate with multiple DGs and loads cannot be controlled by a traditional synchronizer, but needs to control multiple generators and energy storage systems in a coordinated way. This is not a simple job, considering that a microgrid consists of various power electronics-based DGs as well as alternator-based generators that produce power together. This paper introduces the results of research examining an active synchronizing control system that consists of the network-based coordinated control of multiple DGs. Consequently, it provides the microgrid with a deterministic and reliable reconnection to the grid. The proposed method is verified by using the test cases with the experimental setup of a microgrid pilot plant.
Development of Integrated Composite Suspension wire with Optical Fiber
Sone, Young-Cher ; Choi, Hyun-Beom ; Kim, Byung-Jik ; Kim, Young-Tak ; Yun, Kyoung-Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1122~1127
DOI : 10.5370/KIEE.2011.60.6.1122
The thesis here by shows that the extant suspension wire, which is stretched between electric poles to support a variety of communication wires, can be replaced by specially-redesigned cables called OPSW(Composite Suspension Wire with Optical Fiber) which have been devised for the first time in the world so that the functions of both communication and support can be united into one cable which is sure to be successfully installed on site, hence leading to outstanding effects that it can sharply reduce the load applied to electric poles as well as the cost of forthcoming constructions and that it can accordingly make a great contribution to the building of Smart Grid network.
Analysis of Response of a Wind Farm During Grid/inter-tie Fault Conditions
Lee, Hye-Won ; Kim, Yeon-Hee ; Zheng, Tai-Ying ; Lee, Sang-Cheol ; Kang, Yong-Cheol ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1128~1133
DOI : 10.5370/KIEE.2011.60.6.1128
In a wind farm, a large number of small wind turbine generators (WTGs) operate whilst a small number of a large generator do in a conventional power plant. To maintain high quality and reliability of electrical energy, a wind farm should have equal performance to a thermal power plant in the transient state as well as in the steady state. The wind farm shows similar performance to the conventional power plant in the steady state due to the advanced control technologies. However, it shows quite different characteristics during fault conditions in a grid, which gives significant effects on the operation of a wind farm and the power system stability. This paper presents an analysis of response of a wind farm during grid fault conditions. During fault conditions, each WTG might produce different frequency components in the voltage. The different frequency components result in the non-fundamental frequencies in the voltage and the current of a wind farm, which is called by "beats". This phenomenon requires considerable changes of control technologies of a WTG to improve the characteristics in the transient state such as a fault ride-through requirement of a wind farm. Moreover, it may cause difficulties in protection relays of a wind farm. This paper analyzes the response of a wind farm for various fault conditions using a PSCAD/EMTDC simulator.
Energy and Inductance of a HTS Magnet with Various Aspect Ratios
Kang, Myung-Hun ; Kim, Young-Min ; Ku, Dae-Kwan ; Paik, Kyoung-Ho ; Cha, Guee-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1134~1139
DOI : 10.5370/KIEE.2011.60.6.1134
When the aspect ratio of a magnet varies, the magnetic field in the magnet also varies. The critical current of a tape-shaped HTS wire varies with the direction and magnitude of applied magnetic field. Consequently when the aspect ration of a HTS magnet varies, the critical current of a HTS magnet varies. This paper shows the relation between the aspect ratio of a magnet and the energy and inductance of a HTS magnet. The critical current is also shown at various aspect ratio of the magnet. The length of the HTS wire, inner diameter of the magnet, and number of pancake are chosen to be variables which varies the shape of the magnet. For a HTS magnet consisting of pancake windings, calculation results show the number of pancake windings are the prime factor which varied the energy and inductance of the magnet. The inner diameter of the magnet varies the energy and inductance of the magnet a little.
New Loss Minimization Vector Control for Induction Motors
Lee, Hong-Hee ; Khojakhan, Yerganat ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1140~1145
DOI : 10.5370/KIEE.2011.60.6.1140
This paper proposes a new loss minimization control method for the vector controlled induction motors. The aim of the proposed loss minimization method is how to determine the optimal flux reference to minimize the total loss of induction motor. Even though the proposed algorithm is based on the equivalent circuit of induction motor including iron loss and leakage inductance, the algorithm is easy to be found and simple to be implemented. Futhermore, the proposed loss minimization algorithm can be applied easily to the traditional vector control system without any additional hardware. Simulation and experimental results are given to validate the effectiveness of the proposed method.
The Influence of Energy Density upon Detection Time of Information Signal in AF Track Circuit
Kim, Min-Seok ; Hwang, In-Kwang ; Lee, Jong-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1146~1151
DOI : 10.5370/KIEE.2011.60.6.1146
There are two methods for train control in information transmission by using track circuit system and installing wayside transmitter. Information signal is transmitted to the on-board antenna by using rails. Continuous information about train intervals, speed and route is received by on-board antenna in AF track circuit system. The information signal is included with carrier wave and received by magnetic coupling in the on-board antenna. Therefore, it is important to define standard current level in the AF track circuit system. When current flowed to rails is low, magnetic sensors are not operated by decreasing magnetic field intensity. Hence, SNR is decreased because electric field intensity is decreased. When the SNR is decreased, there is the serious influence of noise upon demodulation. So, the frequency of information signal is not extracted in frequency response. Thus, it is possible to happen to train accident and delay as the information signal is not analyzed in the on-board antenna. In this paper, standard energy density is calculated by using Parseval`s theory in UM71c track circuit. Hence, detection time of information signal is presented.
A Single-Phase DC-AC Inverter Using Two Embedded Z-Source Converters
Kim, Se-Jin ; Jung, Young-Gook ; Lim, Young-Cheol ; Choi, Joon-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1152~1162
DOI : 10.5370/KIEE.2011.60.6.1152
In this paper, a single-phase DC-AC inverter using two embedded Z-source converters is proposed. The proposed inverter is composed of two embedded Z-source converters with common DC source and output AC load. The output AC voltage of the inverter is obtained by the difference of output capacitor voltages of each converter. The output voltage of each converter take shape of the asymmetrical AC waveform centering zero voltage. Therefore, the proposed inverter can generate the same output voltage despite low VA rating L-C elements, compared to the conventional inverter using high DC voltage with AC ripple. To verify the validity of the proposed system, the PSIM simulation was achieved under the condition of rapid increase of DC source (110[V]
150[V]) and R-load (50[
]). For controlling the voltage of the inverter system, the one-cycle controller was adopted. As results, the proposed inverter output the constant AC voltage (220[V]rms/60[Hz]) for all conditions. Also, the R-L load and nonlinear diode load were adopted for the proposed inverter loads, and we could know that the its output voltage characteristics were as good as the pure R-load. Finally, the RMS and THD of output AC voltage were examined for the different loads, input DC voltages and reference voltage signals.
Analysis of Accelerated Aging Natural Ester Oil and Mineral Oil in Distributional Transformers
An, Jung-Sik ; Choi, Sun-Ho ; Bang, Jeong-Ju ; Jung, Joong-Il ; Huh, Chang-Su ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1163~1168
DOI : 10.5370/KIEE.2011.60.6.1163
Most transformers use insulating and cooling fluids derived from petroleum crude oil, but mineral oil has some possibility of environmental pollution and fire with explosion. vegetable oil fluids extracted from seed has superior biodegradation and fire-resistant properties including an exceptionally high fire point enhancing fire safety. In this study, it is aimed at the practicality of substituting natural ester dielectric fluid for mineral oil in liquid insulation system of transformers. As a rise in coil winding temperature has a direct influence on transformer life time, it is important to evaluate the temperature rise of coil winding in vegetable oil in comparison with mineral oil. Four transformers for the test are designed with 10KVA, 13.2KV, one phase unit. The temperature are directly measured in insulating oil of these transformers with the two sorts of natural ester and mineral oil dielectric fluid respectively. Experiment for aging carry out two means. First means remained
that transformer of mineral oil were operated at 185% load. Second means is that insulating oils of two natural ester and mineral oil were aged by thermal cycles repeating from
. For the heating, Transformers were operated at 185% load. For the cooling, cooling system was operated in the chamber. Samples were analyzed at 42, 63, 93, 143, 190, 240 300cycles. Analysis contents are dielectric strength, total acid value. Mineral oils compared results of first means with results of second means. And compared two sort natural esters respectively with mineral oil in second means.
A Study on Ion Exchange Method for Effective Ag Doping of Sputtering-Deposited CdTe Thin Film
Kim, Cheol-Joan ; Park, Ju-Sun ; Lee, Woo-Sun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1169~1174
DOI : 10.5370/KIEE.2011.60.6.1169
CdTe thin-film solar cell technology is well known that it can theoretically improve its conversion efficiency and manufacturing costs compared to the conventional silicon solar cell technology, due to its optical band gap energy (about 1.45eV) for solar energy absorption, high light absorption capability and low cost requirements for producing solar cells. Although the prior studies obtained the high light absorption, CdTe thin film solar cell has not been come up to the sufficient efficiency yet. So, doping method was selected for the improvement of the electrical characteristics in CdTe solar cells. Some elements including Cu, Ag, Cd and Te were generally used for the p-dopant as substitutional acceptors in CdTe thin film. In this study, the sputtering-deposited CdTe thin film was immersed in
solution for ion exchange method to dope Ag ions. The effects of immersion temperature and Ag-concentration were investigated on the optical properties and electrical characteristics of CdTe thin film by using Auger electron spectroscopy depth-profile, UV-visible spectrophotometer, and a Hall effect measurement system. The best optical and electrical characteristics were sucessfully obtained by Ag doping at high temperature and concentration. The larger and more uniform diffusion of Ag ions made increase of the Ag ion density in CdTe thin film to decrease the series resistance as well as mede the faster diffusion of light by the metal ions to enhance the light absorption.
Polarization Characteristics of SBN Thin Film by RF Magnetron Sputtering
Kim, Jin-Sa ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1175~1177
DOI : 10.5370/KIEE.2011.60.6.1175
The SBN thin films were deposited on Pt/Ti/
/Si and p-type Si(100) substrate by rf magnetron sputtering method using
ceramic target. SBN thin films deposited were annealed at 600~800[
] by furnace in oxygen atmosphere during 40min. The polarization characteristics have been investigated to confirm the possibility of the SBN thin films for the application to destructive read out ferroelectric random access memory. The maximum remanent polarization and the coercive voltage are 0.6[
], 1.2[V] respectively at annealing temperature of 800[
]. The leakage current density was the
at an applied voltage of 5[V] at annealing temperature of 650[
]. Also, the fatigue characteristics of SBN thin films did not change up to
The Design of 6 inch Down-light by Optimization of the Optical and the Thermal Properties
Kim, Sung-Hyun ; Joung, Young-Gi ; Seo, Bum-Sik ; Yang, Jong-Kyung ; Park, Dae-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1178~1182
DOI : 10.5370/KIEE.2011.60.6.1178
The best methods for distribution controled of LED lighting fixtures is control to designed LED chip array, lens and reflector. However, lens design need distribution design to reflector for low-wattage LED lighting because of difficulty of production and reduction of light efficiency. In addition, it needs maximize of thermal performance to improve the efficiency and reliability of device. As a result, for the height of reflector 40[mm] and Inclination 25[
], we can see the best distribution properties, and, in the thermal properties, junction temperature MCPCB 62.9 [
], FR4 PCB 89.6 [
], FR4 PCB from Via-hole is 63.1 [
]. it may improve for thermal properties for makes the Via-hole.
Color Image Segmentation for Extracting Dental Plaque
Kim, Kyeong-Seop ; Shin, Seung-Won ; Lee, Se-Min ; Jeong, Jin-Sun ; Park, Won-Se ; Kim, Kee-Deog ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1183~1189
DOI : 10.5370/KIEE.2011.60.6.1183
In this study, we propose the unsupervised image segmentation algorithm to estimate dental plaque accumulations on digital imaging with methylene blue disclosed plaque. With this aim, RGB color plane is mapped into HSI coordinates and the circular histogram of Hue is reconstructed by applying Otsu`s threshold level. The histogram distribution on Saturation features is also analyzed by maximizing the variance between a plaque candidate and non-plaque one. The dental plaque regions are resolved by applying the composite decision logics based on the threshold level of Hue and Saturation.
Evaluation of Waist Pressure Using Electroencephalogram(EEG) Signal
Kim, Dong-Jun ; Woo, Seung-Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1190~1195
DOI : 10.5370/KIEE.2011.60.6.1190
This paper presents a waist pressure evaluation method in human sensibility using a electroencephalogram(EEG) signal. For this objective, a size-controllable waist-belt is used. First of all, EEG signals for relaxed state are acquired. Then, the waist-belt of the subject is tightened about 90% of normal state. After a few minutes, the belt of the subject is released. Some necessary preprocessing is performed on the acquired signals, Linear Prediction (LP) coefficients are utilized as the feature parameters extracting the characteristics of EEG signal, and a multi-layer neural network is used for indicating the state of body pressure. The results of the method showed 77.2% of coincidence with body pressure states. This may be compromising results for ssubject-independent sensibility evaluation using EEG signal.
The Assessment on the Sound Quality of Reduced Frequency Selectivity of Hearing Impaired People
An, Hong-Sub ; Park, Gyu-Seok ; Jeon, Yu-Yong ; Song, Young-Rok ; Lee, Sang-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1196~1203
DOI : 10.5370/KIEE.2011.60.6.1196
The reduced frequency selectivity is a typical phenomenon of sensorineural hearing loss. In this paper, we compared two modeling methods for reduced frequency selectivity of hearing impaired people. The two models of reduced frequency selectivity were made using LPC(linear prediction coding) algorithm and bandwidth control algorithm based on ERB(equivalent rectangular bandwidth) of auditory filter, respectively. To compare the effectiveness of two models, we compared the result of PESQ (perceptual evaluation of speech quality) and LLR(log likelihood ratio) using 36 Korean words of two syllables. To verify the effect on noise condition, we mixed white and babble noise with 0dB and -3dB SNR to speech words. As the result, it is confirmed that the PESQ score of bandwidth control algorithm is higher than the score of LPC algorithm, on the other hands, and the LLR score of LPC algorithm is lower than the score of bandwidth control algorithm. It means that both non-linearity and widen auditory filter characteristics caused by reduced frequency selectivity could be more reflected in bandwidth control algorithm than in LPC algorithm.
Development of fall Detection System by Estimating the Amount of Impact and the Status of Torso Posture of the Elderly
Kim, Choong-Hyun ; Lee, Young-Jae ; Lee, Pil-Jae ; Lee, Jeong-Whan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1204~1208
DOI : 10.5370/KIEE.2011.60.6.1204
In this study, we proposed the system that calculates the algorithm with an accelerometer signal and detects the fall shock and it`s direction. In order to gather the activity patterns of fall status and attach on the subject`s body without consciousness, the device needs to be small. With this aim, it is attached on the right side of subject`s waist. With roll and pitch angle which represent the activity of upper body, the fall situation is determined and classified into the posture pattern. The impact is calculated by the vector magnitude of accelerometer signal. And in the case of the elderly keep the same posture after fall, it can distinguish the situation whether they can stand by themselves or not. Our experimental results showed that 95% successful detection rate of fall activity with 10 subjects. For further improvement of our system, it is necessary to include tasks-oriented classifying algorithm to diverse fall conditions.
Principles and Medical Applications of Biomedical Photoacoustic Tomography
Song, Chul-Gyu ; Ryu, Sang-Hun ; Kim, Do-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1209~1214
DOI : 10.5370/KIEE.2011.60.6.1209
Photoacoustics has been broadly studied in biomedicine, for both human and small animal tissues. Photoacoustics uniquely combines the absorption contrast of light or radio frequency waves with ultrasound resolution. Moreover, it is non-ionizing and non-invasive, and is the fastest growing new biomedical method, with clinical applications on the way. This paper provides a brief recap of recent developments in photoacoustics in biomedicine, from basic principles to applications. The emphasized areas include the new imaging modalities as well as translational research topics. A primary PA application in biomedicine is photoacoustic tomography (PAT). The past decade has seen fast developments in both theoretical reconstruction algorithms and innovative imaging techniques, and PAT has been implemented in imaging different tissues, from centimeter-large breast tumors to several micrometer-large single red blood cels (RBC). PAT now provides structural, functional and molecular imaging. Overall, PA techniques for biomedicine are maturing. They have been widely used to study both animal and human tissues. Recently, more and more research focuses on clinical applications. Commercialized PA systems are expected to be available in the near future, and wide clinical PA applications are foreseen.
Development and Experimental Evaluation of the Wireless Illumination Controller with Demand Response for the Smart Grid
Choi, In-Ho ; Lee, Joung-Han ; Hong, Seung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1215~1224
DOI : 10.5370/KIEE.2011.60.6.1215
Recently, a lot of research for the smart grid technology have been carried out to achieve energy efficiency for the electronic products. In order to practically apply this study, smart instruments which are capable of the AMI (Advanced Metering Infrastructure) and DR (Demand Response) function are necessary. However, it is difficult to apply the function of the smart grid to the electronic product that cannot support the smart grid. Accordingly, the efficient use of electric energy is impossible. In order to solve this problem, the electronic product has to be changed into the exclusive electronic product supporting smart grid technology or the smart controller has to be attached the outside of the device. In this study, we developed the smart controller for connecting the electric appliances to the smart grid system. It can be attached to the illumination and the smart grid-based lamp control system at home. We additionally designed the message frame and the protocol to operate the smart controller with the AMI based EMS (Energy Management Server). We developed an experimental system to practically verify functions of the smart controller which is attached to the lighting device. From the system, we showed that the electric source of the illumination can be controlled according to the load change and saved energy effectively. We also confirmed the structural benefit and the energy-efficient effect through the verification of the smart controller.
Building AHU Load Control Algorithm based on Demand Response
Kim, Jeong-Uk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1225~1228
DOI : 10.5370/KIEE.2011.60.6.1225
This paper presents an advanced energy saving algorithm in building. It is important to aggregate a various demand side resource which is controllable on demand response environment. Previous demand side algorithm for building is restricted on peak power. In this paper, we suggest duty cycle algorithm for AHU on demand response to reduce the quantity of building power consumption. The test results show that the proposed algorithm is very effective.
Lateral Dynamic Model of an All-Wheel Steered Articulated Vehicle for Guidance Control
Yun, Kyoung-Han ; Kim, Young-Chol ; Min, Kyung-Deuk ; Byun, Yeun-Sub ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1229~1238
DOI : 10.5370/KIEE.2011.60.6.1229
This paper deals with the lateral dynamic model of an all-wheel steered articulated vehicle to design a guidance controller. Nonlinear dynamic model of articulated vehicle is developed by complementing the model about the BRT system of California PATH in U. S. A. and the Phileas system of the APTS in Netherlands. Linear lateral dynamic model has been derived from the nonlinear dynamic model under some assumptions associated with the driving conditions. To design a guidance controller, we derive a transfer function that is steering angle as input and lateral acceleration as output from the linear lateral dynamic model by applying the parameter of vehicle that is developed by Korea Railroad Research Institute. To validate the dynamic model, nonlinear dynamic model has been compared with a vehicle model that has been programmed in ADAMS, and linear dynamic model has been compared with a nonlinear dynamic model under sime assumptions.
Development of Live-line Insulator Inspection Robot System for both Suspension and Tension Insulator Strings
Park, Joon-Young ; Lee, Jae-Kyung ; Oh, Ki-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1239~1244
DOI : 10.5370/KIEE.2011.60.6.1239
In our previous paper, we developed an insulator inspection robot system for a suspension insulator string in the 345kV power transmission line. However, this robot cannot be applied to a tension insulator string, because its constituent insulators are different in diameter and height from those of a suspension insulator string. To solve this problem, we developed a new live-line insulator inspection robot system that is applicable to both suspension and tension insulator strings. We confirmed its effectiveness through live-line performance tests.
Target Tracking of the Wheeled Mobile Robot using the Combined Visual Servo Control Method
Lee, Ho-Won ; Kwon, Ji-Wook ; Hong, Suk-Kyo ; Chwa, Dong-Kyoung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1245~1254
DOI : 10.5370/KIEE.2011.60.6.1245
This paper proposes a target tracking algorithm for wheeled mobile robots using in various fields. For the stable tracking, we apply a vision system to a mobile robot which can extract targets through image processing algorithms. Furthermore, this paper presents an algorithm to position the mobile robot at the desired location from the target by estimating its relative position and attitude. We show the problem in the tracking method using the Position-Based Visual Servo(PBVS) control, and propose a tracking method, which can achieve the stable tracking performance by combining the PBVS control with Image-Based Visual Servo(IBVS) control. When the target is located around the outskirt of the camera image, the target can disappear from the field of view. Thus the proposed algorithm combines the control inputs with of the hyperbolic form the switching function to solve this problem. Through both simulations and experiments for the mobile robot we have confirmed that the proposed visual servo control method is able to enhance the stability compared to of the method using only either PBVS or IBVS control method.
Study on Very High-Rate Power Line Communications for Smart Grid
Choi, Sung-Soo ; Oh, Hui-Myoung ; Kim, Young-Sun ; Kim, Yong-Hwa ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1255~1260
DOI : 10.5370/KIEE.2011.60.6.1255
In this paper, we study on the reliability of Very High-rate Power Line Communication (VH-PLC) for Smart Grid, so that the resultant data rate is over 400Mbps at a physical layer. Firstly, reviewing the research trend of the PLC, we discuss the required techniques for supporting the Smart Grid. Considering a pre-specification with the value of several parameters, we investigate a multi-carrier modulation technique to overcome limitations of higher rate transmission under power line channel environments. Then, we propose a system specification of the VH-PLC in the sense of enhancing two features. One is resolving the problem of the co-existence of the deployed high-speed PLC according to the published standardization of KS X 4600-1 in Korea. The other is getting better performance on the grid adopting the diverse element techniques, such as multi-carrier modulation, a subcarrier utilization mode, a variable rate LDPC (Low Density Parity Check) code, and a time and frequency diversity technique. Further, a simulation tool, composed of an Event-Driven simulator and a Time-Driven simulator, is developed for the purpose of verifying the system performance and continuously cross-checking the test bench signal of the proposed VH-PLC system.
A Study About the Application Feasibility of EMS IEC 61000-4-6 Test Standard on Electronic Power Meter
Kim, Seok-Gon ; Park, Chang-Ho ; Shin, Dong-Yeol ; Song, Tae-Seung ; Choi, Yong-Sung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1261~1267
DOI : 10.5370/KIEE.2011.60.6.1261
Electricity meters using in Korea are about 1.8 million units. From among these, electronic meters for high voltage, about 170 thousand units were installed to the digital type meter and ones for low voltage installed hundreds of thou-sands of meters through a model project. Recently, low voltage meter are expected to complete the installation within several years. Domestic power metering technology is being beyond a simple framework with an electronic type and is rapidly evolving to intelligent smart metering systems in conjunction with promotion of a national smart grid project. Accordingly, it is important to ensure an immunity of meter for electromagnetic field and environmental noise at the installation site. In this paper, we are going to check the validity of international standard that focusing on RF electromagnetic field immunity of meter to secure the quality and improve the reliability in field operation of meter. And we will verify the validity of test specification focused on actual installation environment and are going to offer the improvement plan of test standard.
Operational Characteristics of Transformer-Type SFCL with or without Neutral Line between the Secondary windings and Superconducting units
Cho, Yong-Sun ; Choi, Hyo-Sang ; Go, Sung-Pil ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1268~1273
DOI : 10.5370/KIEE.2011.60.6.1268
The study on power capacity increase of superconducting fault current limiter (SFCL) is one of the most important researches to apply a SFCL in the power system. To achieve this, we thought that the unbalanced quenching problem generated in series connection of superconducting units should be solved. In this paper, we investigated the quenching characteristics of superconducting units in the transformer-type SFCL with or without the neutral line between secondary windings and superconducting units. In case of transformer-type SFCL without neutral line, the connection structure of superconducting units is identical to that of the resistive-type SFCL connected in series. Therefore, the unbalanced quenching was occurred by difference of critical current between superconducting units. However, in case of transformer-type SFCL with neutral line, the superconducting units with different critical current were simultaneously quenched. It was because the currents induced by secondary winding were separately flowed through the superconducting units. By these results, we confirmed that the resistances and consumption powers of the superconducting units were equally generated.
Study on the Damage Pattern Analysis of a 3 Phase 22.9/3.3kV Oil Immersed Transformer and Judgment of the Cause of Its Ignition
Choi, Chung-Seog ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1274~1279
DOI : 10.5370/KIEE.2011.60.6.1274
The purpose of this paper is to present the manufacturing defect and damage pattern of a 3 phase 22.9/3.3kV oil immersed transformer, as well as to present an objective basis for the prevention of a similar accident and to secure data for the settlement of PL related disputes. It was found that in order to prevent the occurrence of accidents to transformers, insulating oil analysis, thermal image measurement, and corona discharge diagnosis, etc., were performed by establishing relevant regulation. The result of analysis performed on the external appearance of a transformer to which an accident occurred, the internal insulation resistance and protection system, etc., showed that most of the analysis items were judged to be acceptable. However, it was found that the insulation characteristics between the primary winding and the enclosure, those between the ground and the secondary winding, and those between the primary and secondary windings were inappropriate due to an insulating oil leak caused by damage to the pressure relief valve. From the analysis of the acidity values measured over the past 5 years, it is thought that an increase in carbon dioxide (CO2) caused an increase in the temperature inside the transformer and the increase in the ethylene gas increased the possibility of ignition. Even though 17 years have passed since the transformer was installed, it was found that the system`s design, manufacture, maintenance and management have been performed well and the insulating paper was in good condition, and that there was no trace of public access or vandalism. However, in the case of transformers to which accidents have occurred, a melted area between the upper and the intermediate bobbins of the W-phase secondary winding as well as between its intermediate and lower bobbins. It can be seen that a V-pattern was formed at the carbonized area of the transformer and that the depth of the carbonization is deeper at the upper side than the lower side. In addition, it was found that physical bending and deformation occurred inside the secondary winding due to non-uniform pressure while performing transformer winding work. Therefore, since it is obvious that the accident occurred due to a manufacturing defect (winding work defect), it is thought that the manufacturer of the transformer is responsible for the accident and that it is lawful for the manufacture to investigate and prove the concrete cause of the accident according to the Product Liability Law (PLL).
An Assessment on Harmonics Effect in Customer and the Distributed Power System during Grid Connection of Residential Fuel Cell System
Park, Chan-Eom ; Jung, Jin-Soo ; Han, Woon-Ki ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1280~1285
DOI : 10.5370/KIEE.2011.60.6.1280
Recently, due to the use of fossil fuels for electric power production, carbon emissions increased excessively. Thereby, in order to replace fossil fuels, many studies about fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be degradation reason of power quality in the power system. In this paper, we constructed the system for an assessment on harmonics effect. The system is composed with power source, harmonics generation and linear load, fuel cell system. we also performed assessment on harmonics effect in customer and the distributed power system during grid connection of residential fuel cell system. An assessment cases are divided into three. A Case 1 is state that residential load and fuel system are connected to grid, Case 2 is state that residential load and harmonics load are connected to grid, and Case 3 is state that all loads are connected to grid. As a output of fuel cell system is increase, analysis results based on assessment system showed that power quality became more aggravation as effect of harmonics.
Experimental Study on Railway Vibration Isolation of a Large Structure using Isolation Materials
Ryu, Bong-Jo ; Lee, Hong-Gi ; Koo, Kyung-Wan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 6, 2011, Pages 1286~1292
DOI : 10.5370/KIEE.2011.60.6.1286
The paper deals with the vibration isolation of a large structure using an experimental technology. In the case of vibration isolation for the vicinity of a subway or a railroad station, most of vibration isolation techniques using isolation materials with high isolation efficiency only, have been applied. Therefore, the quantitative evaluation and design technologies are required for a vibration isolation of large structures. In this study, firstly, vibration characteristics due to train or subway are analyzed. Secondly, the performance of existing vibration isolation materials such as precision isolation material, elastomer is estimated through the experiments. Thirdly, the performance of a tire isolation material and its frame is tested and evaluated. Finally, it is shown that tire isolation materials can be applied to the vibration isolation or vibration reduction of large structures.