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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 64, Issue 12 - Dec 2015
Volume 64, Issue 11 - Nov 2015
Volume 64, Issue 10 - Oct 2015
Volume 64, Issue 9 - Sep 2015
Volume 64, Issue 8 - Aug 2015
Volume 64, Issue 7 - Jul 2015
Volume 64, Issue 6 - Jun 2015
Volume 64, Issue 5 - May 2015
Volume 64, Issue 4 - Apr 2015
Volume 64, Issue 3 - Mar 2015
Volume 64, Issue 2 - Feb 2015
Volume 64, Issue 1 - Jan 2015
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Reliability Evaluation with Wind Turbine Generators and an Energy Storage System for the Jeju Island Power System
Oh, Ungjin ; Lee, Yeonchan ; Lim, Jintaek ; Choi, Jaeseok ; Yoon, Yongbeum ; Chang, Byunghoon ; Cho, Sungmin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 1~7
DOI : 10.5370/KIEE.2015.64.1.001
This paper proposes probabilistic reliability evaluation model of power system considering Wind Turbine Generator(WTG) integrated with Energy Storage System(ESS). Monte carlo sample state duration simulation method is used for the evaluation. Because the power output from WTG units usually fluctuates randomly, the power cannot be counted on to continuously satisfy the system load. Although the power output at any time is not controllable, the power output can be utilized by ESS. The ESS may make to smooth the fluctuation of the WTG power output. The detail process of power system reliability evaluation considering ESS cooperated WTG is presented using case study of Jeju island power system in the paper.
A Study on Parameter Estimation of the Synchronous Generator System based on the Modified PSO
Choi, Hyung-Joo ; Kim, In-Soo ; Lee, Heung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 8~15
DOI : 10.5370/KIEE.2015.64.1.008
This paper includes a method for estimating the parameter of a synchronous generator and exciter using the modified particle swarm optimization. A solid round rotor synchronous generator and exciter have been modeled with the saturation function. They are regarded as state of being cooperative to a infinite bus. The behavior characteristic of all particles assigned to a parameter needs to be reflected in the PSO algorithm to fine out more close result to the optimal solution. The results of the simulation to estimate the parameters of the synchronous generator and exciter in the modified PSO algorithm are described.
Operation of Battery Energy Storage System for Governor Free and its Effect
Cho, Sung-Min ; Jang, Byung-Hoon ; Yoon, Yong-Bum ; Jeon, Woong-Jae ; Kim, Chulwoo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 16~22
DOI : 10.5370/KIEE.2015.64.1.016
As the development of Battery Energy Storage System(BESS) and the increasing of intermittent energy sources like wind power and photovoltaic, the application of BESS in load frequency control is considered as an effective method. To evaluate the effectiveness of BESS application in frequency control, we defined a governor free model of BESS to conduct dynamic simulation. Using the BESS dynamic model, we implemented the power system dynamic model including steam, gas and hydro turbine generators. In this paper we study the control performance of BESS in primary frequency control. The effect of BESS speed regulation rate and response time on governor free operation is investigated. In addition, we compared BESS from steam turbine generator in view point of frequency regulation.
Analysis of Impact on Voltage Stability by Starting Synchronous Condenser in Jeju AC Network
Choi, Soon-Ho ; Lee, Seong-Doo ; Kim, Chan-Ki ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 23~28
DOI : 10.5370/KIEE.2015.64.1.023
Two old synchronous condensers in Jeju are being replaced by new machines to operate Jeju AC network with Haenam-Jeju HVDC system stably. Before new synchronous condensers operate on site, voltage stability analysis is conducted to verify stable operation of jeju AC network. Through impedance analysis of the synchronous machine, transformer and ac network, the equivalent circuit is constructed and the voltage drop during start-up is calculated. Then, PSS/E fault analysis is performed to acquire short-circuit capacity according to the generator operation scenarios. Voltage variation when starting synchronous condenser is simulated in PSCAD/EMTDC and satisfies the operating condition of jeju AC network and HVDC #1 system.
Method to Select Optimal Device for Mitigating Voltage Sag Based on Voltage Sag Assessment
Lee, Kyebyung ; Han, Jong-Hoon ; Jang, Gilsoo ; Park, Chang-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 29~34
DOI : 10.5370/KIEE.2015.64.1.029
This paper presents a method to select optimal device for mitigating voltage sags. The method is based on economic evaluation and voltage sag assessment involving sag duration as well as magnitude. The economic evaluation is performed by using the operation cost and economic benefit of the mitigation devices. The optimal device can be determined from the values of NPV (net present value) which is widely accepted in cost-benefit analysis. The proposed method can help sensitive customers to select optimal mitigation device. In this paper, the case study considering two sensitive customers was performed by using the proposed method.
The Optimal Microgrid Configuration Depending on the Change of Average Wind Speed and Fuel Cost
Kim, Kyu-Ho ; Lim, Sung-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 35~40
DOI : 10.5370/KIEE.2015.64.1.035
This paper presents the optimal network configuration for electric stations using HOMER software. For the given data such as annual average wind speed and grid costs, this software calculates the NPC(Net Present Cost), operating cost and COE(Cost of Energy). Based on these simulation results, it is possible to find the optimal network configuration for electric stations depending on the grid cost and average wind speed. When the rising grid cost is considered, it is essential to use grid and renewable energy together. Depending on the increase of the grid cost, NPC of the configuration using renewable energy and grid can be gradually getting smaller than NPC of the configuration using only grid.
Load Forecasting using Hierarchical Clustering Method for Building
Hwang, Hye-Mi ; Lee, Sung-Hee ; Park, Jong-Bae ; Park, Yong-Gi ; Son, Sung-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 41~47
DOI : 10.5370/KIEE.2015.64.1.041
In recent years, energy supply cases to take advantage of EMS(Energy Management System) are increasing according to high interest of energy efficiency. The important factor for essential and economical EMS operation is the supply and demand plan the hourly power demand of building load using the hierarchical clustering method of variety statistical techniques, and use the real historical data of target load. Also the estimated results of study are obtained the reliability through separate tests of validity.
CIM-based System for Real-time Voltage Stability Analysis
Lee, Sung-Woo ; Jang, Moon-Jong ; Seo, Dong-Wan ; Namkoong, Won ; Heo, Soung-Ouk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 48~56
DOI : 10.5370/KIEE.2015.64.1.048
There is a wide variety of system and applications in the power system. However, they have compatibility issues because they use different data standard and communication method. With the introduction of the smart grid, power system has been grow and diversified. Therefore power system need to be compatible with each other and the interoperability between applications is increasingly important. Thus, the IEC established IEC61970 and CIM Standard data exchange model for interoperability and system integration. Server-Client system was constructed which using CIM HSDA(Part4), a standard communication model, presented in IEC 619710. Also, self-developed real-time voltage stability analysis application and contingency analysis application was used. CIM HSDA was used for data input and real-time analysis. Tolerance of result which is in the range of allowable derived by Perform real-time voltage stability and contingency analysis of Jeju power system, and then compare it's result with PSS/E result.
A Decision Method for the Optimal Insertion Resistance of a Superconducting Fault Current Limiter with Reduction of an Asymmetric Fault Current
Kim, Chang-Hwan ; Kim, Kyu-Ho ; Rhee, Sang-Bong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 57~63
DOI : 10.5370/KIEE.2015.64.1.057
Fault currents characteristics contain decaying DC offset. First cycle peak value of fault currents is higher than steady-state fault current value. These characteristics can affect the operation of protective device. To reduce the asymmetric fault current, the method using a series connection of two hybrid-type Superconducting Fault Current Limiter(SFCL) components, an auxiliary SFCL and a main SFCL, has been proposed. The auxiliary SFCL limits the first half cycle fault current, while main SFCL limits the steady state fault currents. This paper proposed a decision method of the optimal insertion resistance of auxiliary and main SFCL components. To verify the effectiveness of proposed scheme, the various simulations are performed by using Electromagnetic Transient Program(EMTP).
Comparison and Analysis of Armature Reaction Magnetic Field of Linear Generator with Coreless/Cored Type Three Phases Concentrated Winding by using Space Harmonic Analytical Method
Seo, Sung-Won ; Koo, Min-Mo ; Kang, Han-Bit ; Choi, Jang-Young ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 64~71
DOI : 10.5370/KIEE.2015.64.1.064
This paper deals with analysis of armature reaction magnetic field of linear generator with three phases coreless/cored type concentrated winding. On the basis of a magnetic vector potential and Maxwell's equations, governing equations to predict armature reaction field are derived, and current density modeling is also performed analytically by using the Fourier series expansion. The analytical method used in this paper is confirmed by comparing with finite element analysis results.
A Study on the Polarity Discrimination Method of the Stator Windings for 3 Phase Induction Motors based on the Residual Magnetism and I Winding Connection
Choi, Soon-Man ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 72~77
DOI : 10.5370/KIEE.2015.64.1.072
When connecting 6 lead wires from stator windings to the terminals of 3 phase induction motors for Y or
connection, it is feared that the polarities of windings could be reversed each other if the wire tags are lost or erased, resulting in inadmissibly high current to motors in case of starting. To protect motors against such situations, some test procedures are necessary during wire connection which need to be easy ways to electricians without particular tools except a general multi-tester and with less time-consuming in the field. This study focuses on a test measure to satisfy these requirements which is able to provide them a convenient procedure for winding polarity discrimination considering the field condition. Here, the proposed measure utilizes the residual magnetism of the rotor and checks the indication of voltage or current at windings which are induced by the residual flux of rotor when rotating it by hands with 3 stator windings connected in the form of I connection. Principle characteristics and experiment results for this method are analyzed in the view of the effectiveness and applicability for the winding polarity discrimination.
Phone Case using the EBG Structure for Reducing SAR
Oh, Doyoung ; Yoo, Hyoungsuk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 78~81
DOI : 10.5370/KIEE.2015.64.1.078
This paper investigates the performance of phone case with different permittivities like plastic, urethane and silicone. Then, we put an electromagnetic band gap (EBG) structure in phone case to reduce the specific absorption rate (SAR). In order to design the phone case, a loop antenna for PCS 1900 band was used. The phone case consists of a hairpin-like EBG structure that is more compact than other EBG structures. The SEMCAD X fdtd simulation results showed that, this proposed phone case can reduce SAR by 13 - 30% at similar power that is radiated by the antenna. This phone case can be used in future to reduce the SAR from mobile phones.
A Technique of Feature Vector Generation for Eye Region Using Embedded Information of Various Color Spaces
Park, Jung-Hwan ; Shin, Pan-Seop ; Kim, Guk-Boh ; Jung, Jong-Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 82~89
DOI : 10.5370/KIEE.2015.64.1.082
The researches of image recognition have been processed traditionally. Especially, face recognition technology has been received attractions with advance and applied to various areas according as camera sensor embedded into many devices such as smart phone. In this study, we design and develop a feature vector generation technique of face for making animation caricatures using methods for face detection which are previous stage of face recognition. At first, we detect both face region and detailed eye region of component element by Viola&Johns's realtime detection method which are called as ROI(Region Of Interest). And then, we generate feature vectors of eye region by utilizing factors as opposed to the periphery and by using appearance information of eye. At this point, we focus on the embedded information in many color spaces to overcome the problems which can be occurred by using one color space. We propose a feature vector generation method using information from many color spaces. Finally, we experiment the test of feature vector generation by the proposed method with enough quantity of sample picture data and evaluate the proposed method for factors of estimating performance such as error rate, accuracy and generation time.
Optimal Design of Magnetic Levitation Controller Using Advanced Teaching-Learning Based Optimization
Cho, Jae-Hoon ; Kim, Yong-Tae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 90~98
DOI : 10.5370/KIEE.2015.64.1.090
In this paper, an advanced teaching-learning based optimization(TLBO) method for the magnetic levitation controller of Maglev transportation system is proposed to optimize the control performances. An attraction-type levitation system is intrinsically unstable and requires a delicate control. It is difficult to completely satisfy the desired performance through the methods using conventional methods and intelligent optimizations. In the paper, we use TLBO and clonal selection algorithm to choose the optimal control parameters for the magnetic levitation controller. To verify the proposed algorithm, we compare control performances of the proposed method with the genetic algorithm and the particle swarm optimization. The simulation results show that the proposed method is more effective than conventional methods.
Design of RBF Neural Networks Based on Recursive Weighted Least Square Estimation for Processing Massive Meteorological Radar Data and Its Application
Kang, Jeon-Seong ; Oh, Sung-Kwun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 99~106
DOI : 10.5370/KIEE.2015.64.1.099
In this study, we propose Radial basis function Neural Network(RBFNN) using Recursive Weighted Least Square Estimation(RWLSE) to effectively deal with big data class meteorological radar data. In the condition part of the RBFNN, Fuzzy C-Means(FCM) clustering is used to obtain fitness values taking into account characteristics of input data, and connection weights are defined as linear polynomial function in the conclusion part. The coefficients of the polynomial function are estimated by using RWLSE in order to cope with big data. As recursive learning technique, RWLSE which is based on WLSE is carried out to efficiently process big data. This study is experimented with both widely used some Machine Learning (ML) dataset and big data obtained from meteorological radar to evaluate the performance of the proposed classifier. The meteorological radar data as big data consists of precipitation echo and non-precipitation echo, and the proposed classifier is used to efficiently classify these echoes.
Evolutionary Nonlinear Regression Based Compensation Technique for Short-range Prediction of Wind Speed using Automatic Weather Station
Hyeon, Byeongyong ; Lee, Yonghee ; Seo, Kisung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 107~112
DOI : 10.5370/KIEE.2015.64.1.107
This paper introduces an evolutionary nonlinear regression based compensation technique for the short-range prediction of wind speed using AWS(Automatic Weather Station) data. Development of an efficient MOS(Model Output Statistics) is necessary to correct systematic errors of the model, but a linear regression based MOS is hard to manage an irregular nature of weather prediction. In order to solve the problem, a nonlinear and symbolic regression method using GP(Genetic Programming) is suggested for a development of MOS wind forecast guidance. Also FCM(Fuzzy C-Means) clustering is adopted to mitigate bias of wind speed data. The purpose of this study is to evaluate the accuracy of the estimation by a GP based nonlinear MOS for 3 days prediction of wind speed in South Korean regions. This method is then compared to the UM model and has shown superior results. Data for 2007-2009, 2011 is used for training, and 2012 is used for testing.
Design of Fuzzy k-Nearest Neighbors Classifiers based on Feature Extraction by using Stacked Autoencoder
Rho, Suck-Bum ; Oh, Sung-Kwun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 113~120
DOI : 10.5370/KIEE.2015.64.1.113
In this paper, we propose a feature extraction method using the stacked autoencoders which consist of restricted Boltzmann machines. The stacked autoencoders is a sort of deep networks. Restricted Boltzmann machines (RBMs) are probabilistic graphical models that can be interpreted as stochastic neural networks. In terms of pattern classification problem, the feature extraction is a key issue. We use the stacked autoencoders networks to extract new features which have a good influence on the improvement of the classification performance. After feature extraction, fuzzy k-nearest neighbors algorithm is used for a classifier which classifies the new extracted data set. To evaluate the classification ability of the proposed pattern classifier, we make some experiments with several machine learning data sets.
Sampled-Data Control of LPV Systems with Time-varying Delay
Liu, Yajuan ; Lee, Sangmoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 121~127
DOI : 10.5370/KIEE.2015.64.1.121
This paper considers the problem of sampled-data control for continuous linear parameter varying (LPV) systems. It is assumed that the sampling periods are arbitrarily varying but bounded. Based on the input delay approach, the sampled-data control LPV system is transformed into a continuous time-delay LPV system. Some less conservative stabilization results represented by LMI (Linear Matrix Inequality) are obtained by using the Lyapunov-Krasovskii functional method and the reciprocally combination approach. The proposed method for the designed gain matrix should guarantee asymptotic stability and a specified level of performance on the closed-loop hybrid system. Numerical examples are presented to demonstrate the effectiveness and the improvement of the proposed method.
Design of Very Short-term Precipitation Forecasting Classifier Based on Polynomial Radial Basis Function Neural Networks for the Effective Extraction of Predictive Factors
Kim, Hyun-Myung ; Oh, Sung-Kwun ; Kim, Hyun-Ki ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 128~135
DOI : 10.5370/KIEE.2015.64.1.128
In this study, we develop the very short-term precipitation forecasting model as well as classifier based on polynomial radial basis function neural networks by using AWS(Automatic Weather Station) and KLAPS(Korea Local Analysis and Prediction System) meteorological data. The polynomial-based radial basis function neural networks is designed to realize precipitation forecasting model as well as classifier. The structure of the proposed RBFNNs consists of three modules such as condition, conclusion, and inference phase. The input space of the condition phase is divided by using Fuzzy C-means(FCM) and the local area of the conclusion phase is represented as four types of polynomial functions. The coefficients of connection weights are estimated by weighted least square estimation(WLSE) for modeling as well as least square estimation(LSE) method for classifier. The final output of the inference phase is obtained through fuzzy inference method. The essential parameters of the proposed model and classifier such ad input variable, polynomial order type, the number of rules, and fuzzification coefficient are optimized by means of Particle Swarm Optimization(PSO) and Differential Evolution(DE). The performance of the proposed precipitation forecasting system is evaluated by using KLAPS meteorological data.
Design of Knee-Pelvis Joint in the Biped Robot for Shock Reduction and Gravity Compensation
Kim, Young-Min ; Kim, Yong-Tae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 136~142
DOI : 10.5370/KIEE.2015.64.1.136
In the paper, a design method of knee and pelvis joint in the biped robot is proposed for shock absorption and gravity compensation. Similarly to the human's body, the knee joints of the biped robot support most body weight and get a shock from the landing motion of the foot on the floor. The torque of joint motor is also increased sharply to keep the balance of the robot. Knee and pelvis joints with the spring are designed to compensate the gravity force and reduce the contact shock of the robot. To verify the efficiency of the proposed design method, we develope a biped robot with the joint mechanism using springs. At first, we experiment with the developed robot on the static motions such as the bent-knee posture both without load and with load on the flat ground, and the balance posture on the incline plane. The current of knee joint is measured to analyze the impact force and energy consumption of the joint motors. Also, we observe the motor current of knee and pelvis joints for the walking motion of the biped robot. The current responses of joint motors show that the proposed method has an effect on shock reduction and gravity compensation, and improve the energy efficiency of walking motions for the biped robot.
A New Floating Inductor Using A Voltage Differencing Transconductance Amplifier
Bang, Junho ; Lee, Jong-Yeol ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 143~148
DOI : 10.5370/KIEE.2015.64.1.143
In this paper a new method is proposed for realizing active floating inductors from voltage differencing transconductance amplifier(VDTA) which is being studied nowadays. This proposed method employs only one VDTA and one transconductance for designing an active inductor from a passive floating inductor and implementing it to integrated circuits. The number of CMOS transistors can be considerably reduced from 6~18 as 1~3 gm circuits can be eliminated and even without R the design can be made, which can help in reducing the size of the circuit and power consumption. The proposed VDTA floating inductor was successfully used in constructing 1 MHz second order biquad active bandpass filter and bandwidth could be adjusted from 77kHz~1.59MHz by the changes made in gm from 6uS~20uS.
Harmonic and Interhamonic Detection and Estimation of Power Signal using Subband MUSIC/ESPRIT
Choi, Hun ; Bae, Hyeon-Deok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 149~158
DOI : 10.5370/KIEE.2015.64.1.149
This paper proposes a subband filtering technique to the MUSIC and the ESPRIT algorithm for estimating the magnitude and frequency of the harmonics of power signal. In proposed method, the input power signal is decomposed to the odd harmonics and the even harmonics respectively by the filter bank system. The amplitude and the frequency estimation of the decomposed harmonics are carried out using the MUSIC and the ESPRIT method. Subband filtering can reduce the autocorrelation matrix size of input data, and spectrum leakage between adjacent harmonics. Therefore, this subband technique has advantage in computational cost and estimation accuracy compared to fullband MUSIC and ESPRIT. To demonstrate the performance of the method, computer simulations are performed to the synthesized input signal, and experiment results are compared in subband and fullband cases.
Detection of Color Information Using Optical Method
Kim, Ji-Sun ; Jung, Gu-In ; Lee, Tae-Hee ; Choi, Ju-Hyeon ; Oh, Han-Byeol ; Kim, A-Hee ; Jung, Hyon-Chel ; Jun, Jae-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 159~164
DOI : 10.5370/KIEE.2015.64.1.159
Color is distinguished due to the light in which natural light is reflected by object and made with combination of RGB(red, green, blue; three colors). This study proposes color analysis system with optical method to be used conveniently. Color information of sample is determined with the optical sensor. By using the CIE diagram in particular, it detects purity value and wavelength. The method to distinguish color is very economical, simple, and convenient. The result can be used to confirm accurate information of color for various applications.
The Analysis of Strength and Driving Characteristic according to Design of Traction Motor for 8200 Electric Locomotive Series
Lim, Chae-Woong ; Yun, Cha-Jung ; Kim, Jae-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 165~170
DOI : 10.5370/KIEE.2015.64.1.165
In this paper, The strength and driving characteristics of it were investigated according to developing the traction motor for 8200 electric locomotive series. For this purpose, Flux density strength was analyzed and then structural strength was investigated such as a stator frame, design of the rotor shaft bearing according to the design process. In addition, the traction motor operating point was analyzed according to slip frequency variation at a power source frequency. As the results of analysis on torque-speed characteristic curve, we was confirmed that traction motor was controlled as torque control prior to motor speed 1610[rpm], power control between 1610[rpm] and 2500[rpm] and breakdown torque control more than motor speed 2500[rpm].
The Evaluation of Energy Saving using Ultrathin Heat Insulation in Railway Electrification Substation
Kim, Hyungchul ; Jang, Junghoon ; Shin, Sungkwon ; Park, Yongsub ; Kim, Sangam ; Kim, Hyeong Rae ; Hyun, Byungsoo ; Kim, Jinho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 171~175
DOI : 10.5370/KIEE.2015.64.1.171
In this paper, because of global environmental problems such as energy shortage and abnormal climate, green energy development and energy saving technology development is being magnified. Heat insulation, the most basic and traditional energy saving method, is highly expected. Especially, simple and advanced heat insulation technique based on Nano material is promising future technology. The railway system also requires heat insulation. Especially, traditional heat insulator such as glass wool has been adopted frequently to rolling stock. The heat insulator is also adopted in general railway service buildings. Take account of cost-effective heat blocking performance, the heat insulator shall be adopted in diverse fields such as electric power, railroad, signal and communication. The only and direct solution for this problem is installing heat insulator with outstanding endurance, corrosion resistance and heat resistance to block outer heat Upgrading heat specification of equipment can be a solution, but since price and maintenance cost rise severely, this plan might be incongruous. In this research, energy saving effect of ultrathin heat insulator film was demonstrated by installing the film on roof of electrical room.
Improving Regenerative Break Energy Efficiency and Voltage Regulation Capability of DC Electric Railway by Coordination of VSC and EDLC
Jeon, Go-Woon ; Yoo, Hyeong-Jun ; Park, Jae-Sae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 176~181
DOI : 10.5370/KIEE.2015.64.1.176
In the DC electric railway system, the effective use of regenerative break energy is an important issue. Since regenerative break energy causes voltage rise or drop in the system, it should be also solved effectively. To solve the problems, applying electric double layer capacitor (EDLC) or voltage source converter (VSC) to the DC electric railway system has been studying. In this paper, the coordination of EDLC and VSC is proposed to solve the problem effectively with its coordinated control algorithm. The proposed method is tested to show its feasibility using Matlab/Simulink.
A Study on Development of Open-Phase Protector Having Leakage Current Generation and Incapable Operation Prevention at Open-Phase Accident
Kwak, Dong-Kurl ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 182~187
DOI : 10.5370/KIEE.2015.64.1.182
In the three-phase power system, when any one-phase or two-phases is open-phase, the unbalanced current flows and the single-phase power supplies to three-phase loads. Specially, motor coil and transformer coil receive over-current. As a result, great damage as well as electrical fire can occur to the power system. In order to improve these problems, this paper proposes that an open-phase detection device is designed by a new algorithm using electric potential difference between the resultant voltage of neutral point and ground, and a control circuit topology of open-phase protector is composed of highly efficient semiconductor devices. It improves response speed and reliability. The control algorithm circuit also operates the cut-off of a conventional residual current protective device (RCD) which flows an enforced leakage current to ground wire at open-phase accident. Furthermore, time delay circuit is added to prevent the incapable operation of open-phase protector about instantaneous open-phase not open-phase fault. The time delay circuit improves more reliability.
Study on Measurement Error Reduction Technique when Measuring Touch and Step Voltage of Grounding System
Kim, Dong-Woo ; Lim, Young-Bea ; Lee, Sang-Ick ; Choi, Myeong-Il ; Moon, Hyun-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 188~195
DOI : 10.5370/KIEE.2015.64.1.188
This paper presents measurement error reduction technique of touch and step voltage of grounding system based on numerical analysis. When measuring touch and step voltage of grounding system, auxiliary current probes should be located at suitable places. However, the auxiliary probes can not be located at suitable places in such cases as there are buildings and pavements. Therefore, in this paper, we provided measurement error reduction technique of touch and step voltage of grounding system according to the positions of auxiliary probes and angle between auxiliary probes. Also, measurement error analyses of touch and step voltage of grounding system have been conducted using more than one current probe. Based on these analyses, recommended positions of auxiliary probes within allowable measurement errors were presented.
Surge Immunity Performance Enhancement Techniques on Battery Management System
Kim, Young-Sung ; Rim, Seong-Jeong ; Seo, Woohyun ; Jung, Jeong-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 64, issue 1, 2015, Pages 196~200
DOI : 10.5370/KIEE.2015.64.1.196
The switching noise in the power electronics of the power conversion equipment (Power Conditioning System) for large energy storage devices are generated. Since the burst-level transient noise from being generated in the power system at a higher power change process influences the control circuit of the low voltage driver circuit. Noise may cause the malfunction of the control device even if no dielectric breakdown leads to a control circuit. To overcome this, this paper proposes the installation of an additional nano-surge protection device on the power supply DC output circuit of the battery management unit.