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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 65, Issue 9 - Sep 2016
Volume 65, Issue 8 - Aug 2016
Volume 65, Issue 7 - Jul 2016
Volume 65, Issue 6 - Jun 2016
Volume 65, Issue 5 - May 2016
Volume 65, Issue 4 - Apr 2016
Volume 65, Issue 3 - Mar 2016
Volume 65, Issue 2 - Feb 2016
Volume 65, Issue 1 - Jan 2016
Selecting the target year
An Analysis on Fault Response Characteristics in Low Voltage DC Distribution System
Noh, Chul-Ho ; Gwon, Gi-Hyeon ; Song, Jong-Il ; Han, Joon ; Oh, Yun-Sik ; Kim, Chul-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 911~917
DOI : 10.5370/KIEE.2016.65.6.911
DC-based power system is paid attention as interests in energy efficiency and power quality are increased. However, standardization and researches for commercializing Low Voltage DC(LVDC) distribution system are still insufficient. Protection system, which is closely related with reliability, power quality, safety, and life expectancy of components in power system, is also included. This paper therefore analyzes fault response characteristics in LVDC distribution system as a preliminary study on protection schemes. A stepwise analysis on fault current from both AC/DC converter and DC/DC converter is performed and related expressions are derived. And then, modeling and simulation with various conditions are conducted by using ElectroMagnetic Transients Program (EMTP) to verify analysis results. Based on research results in the paper, direction for development of protection schemes for LVDC distribution system is suggested.
A Study on Centralized Wind Power Forecasting Based on Time Series Models
Wi, Young-Min ; Lee, Jaehee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 918~922
DOI : 10.5370/KIEE.2016.65.6.918
As the number of wind farms operating has increased, the interest of the central unit commitment and dispatch for wind power has increased as well. Wind power forecast is necessary for effective power system management and operation with high wind power penetrations. This paper presents the centralized wind power forecasting method, which is a forecast to combine all wind farms in the area into one, using time series models. Also, this paper proposes a prediction model modified with wind forecast error compensation. To demonstrate the improvement of wind power forecasting accuracy, the proposed method is compared with persistence model and new reference model which are commonly used as reference in wind power forecasting using Jeju Island data. The results of case studies are presented to show the effectiveness of the proposed wind power forecasting method.
Capacity Credit and Reasonable ESS Evaluation of Power System Including WTG combined with Battery Energy Storage System
Oh, Ungjin ; Lee, Yeonchan ; Choi, Jaeseok ; Lim, Jintaek ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 923~933
DOI : 10.5370/KIEE.2016.65.6.923
This paper proposes a new method for evaluating Effective Load Carrying Capability(ELCC) and capacity credit(C.C.) of power system including Wind Turbine Generator(WTG) combined with Battery Energy Storage System(BESS). WTG can only generate electricity power when the fuel(wind) is available. Because of fluctuation of wind speed, WTG generates intermittent power. In view point of reliability of power system, intermittent power of WTG is similar with probabilistic characteristics based on power on-off due to mechanical availability of conventional generator. Therefore, high penetration of WTG will occur difficulties in power operation. The high penetration of numerous and large capacity WTG can make risk to power system adequacy, quality and stability. Therefore, the penetration of WTG is limited in the world. In recent, it is expected that BESS installed at wind farms may smooth the wind power fluctuation. This study develops a new method to assess how much is penetration of WTG able to extended when Wind Turbine Generator(WTG) is combined with Battery Energy Storage System(BESS). In this paper, the assessment equation of capacity credit of WTG combined with BESS is formulated newly. The simulation program, is called GNRL_ESS, is developed in this study. This paper demonstrates a various case studies of ELCC and capacity credit(C.C.) of power system containing WTG combined with BESS using model system as similar as Jeju island power system. The case studies demonstrate that not only reasonable BESS capacity for a WTG but also permissible penetration percent of WTG combined with BESS and reasonable WTG capacity for a BESS can be decided.
Short-term Electric Load Forecasting Using the Realtime Weather Information & Electric Power Pattern Analysis
Kim, Il-Ju ; Lee, Song-Keun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 934~939
DOI : 10.5370/KIEE.2016.65.6.934
This paper made short-term electric load forecasting by using temperature data at three-hour intervals (9am, 12pm, 3pm, and 6pm) provided by the Korea Meteorological Administration (KMA). In addition, the electric power pattern was created using existing electric power data, and temperature sensitivity was derived using temperature and electric power data. We made power load forecasting program using LabVIEW, a graphic language.
Zero Sequence Impedance of Yg-Yg Three Phase Core Type Transformer
Jo, Hyunsik ; Cho, Sungwoo ; Shin, Changhoon ; Cha, Hanju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 940~945
DOI : 10.5370/KIEE.2016.65.6.940
In this paper, zero sequence equivalent circuit of Yg-Yg three phase core-type transformer is analyzed. Many problems by iron core structure of the three phase transformer due to asymmetric three phase lines, which includes line disconnection, ground fault, COS OFF, and unbalanced load are reported in the distribution system. To verify a feasibility of zero sequence impedance of Yg-Yg type three phase transformer, fault current generation in the three phase core and shell-type Yg-Yg transformer is compared by PSCAD/EMTDC when single line ground fault is occurred. As a result, shell-type transformer does not affect the flow of fault current, but core-type transformer generate an adverse effect by the zero sequence impedance. The adverse effect is explained by the zero sequence equivalent circuit of core-type transformer and Yg-Yg type three phase core-type transformer supplies a zero sequence fault current to the distribution system.
A Study on Decision-making Criteria in Industrial Sector for Electric Load Aggregation
Kim, Sung-Yul ; Kim, Dong-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 946~954
DOI : 10.5370/KIEE.2016.65.6.946
Energy industry is undergoing a paradigm shift in customer participation in the smartgrid. Customers traditionally consume electrical power. But nowadays not only do they generate electricity from private distributed generations, they can participate in demand response programs with their negawatt power which means a theoretical unit of power representing an amount of energy saved. Therefore development of decision-making criteria for electric load aggregation becomes a greater consideration as an amount of energy saved from demand response resources increases. This paper proposes load aggregators` decision-making criteria in the industrial sector where it made up the largest portion in demand response portfolio in order to assure reliability performance for demand response resources.
Enhanced Fault Location Algorithm for Short Faults of Transmission Line
Lee, Kyung-Min ; Park, Chul-Won ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 955~961
DOI : 10.5370/KIEE.2016.65.6.955
Fault location estimation is an important element for rapid recovery of power system when fault occur in transmission line. In order to calculate line impedance, most of fault location algorithm uses by measuring relaying waveform using DFT. So if there is a calculation error due to the influence of phasor by DC offset component, due to large vibration by line impedance computation, abnormal and non-operation of fault locator can be issue. It is very important to implement the robust fault location algorithm that is not affected by DC offset component. This paper describes an enhanced fault location algorithm based on the DC offset elimination filter to minimize the effects of DC offset on a long transmission line. The proposed DC offset elimination filter has not need any erstwhile information. The phase angle delay of the proposed DC offset filter did not occurred and the gain error was not found. The enhanced fault location algorithm uses DFT filter as well as the proposed DC offset filter. The behavior of the proposed fault location algorithm using off-line simulation has been verified by data about several fault conditions generated by the ATP simulation program.
A Study on Estimation Method for Optimal Composition Rate of Hybrid ESS Using Lead-acid and Lithium-ion Batteries
Park, Soo-Young ; Ryu, Sang-Won ; Park, Jae-Bum ; Kim, Byung-Ki ; Kim, Mi-Young ; Rho, Dae-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 962~968
DOI : 10.5370/KIEE.2016.65.6.962
The large scaled lead-acid battery is widely used for efficient operation of the photovoltaic system in many islands. However, lithium-ion battery is now being introduced to mitigate the fluctuation of wind power and to replace lead-acid battery. Therefore, hybrid ESS(Energy Storage system) that combines lithium-ion battery with lead-acid battery is being required because lithium-ion battery is costly in present stage. Under this circumstance, this paper presents the optimal algorithm to create composition rate of hybrid ESS by considering fixed and variable costs in order to maximize advantage of each battery. With minimization of total cost including fixed and variable costs, the optimal composition rate can be calculated based on the various scenarios such as load variation, life cycle and cost trend. From simulation results, it is confirmed that the proposed algorithms are an effective tool to produce a optimal composition rate.
A Study on Establishing Operation Mathematical Model for Optimum Capacity Estimation of the ESS Applications for each in the Nationwide Perspective
Kim, Jung-Hoon ; Youn, Seok-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 969~978
DOI : 10.5370/KIEE.2016.65.6.969
Around the world are increasing the demand for ESS. Currently, the domestic is expected to benefit by operating ESS. In the domestic, it is expected to benefit from operations of the installed ESS because of the introduction of ESS less capacity. However ESS capacity to the maximum profit occurs is unknown. ESS is different from the charge-discharge characteristics and the reserve to replace, depending on the application. Therefore, it should be established in accordance with the ESS optimal capacity according to the purpose used because it can maximize the quality and efficiency of the electric energy. To the ESS optimal capacity estimation by the purpose used, It should compare the investment cost caused by ESS facility installation and operation cost caused by operating ESS. In this paper, the operation mathematical model for estimating marginal operation costs established. In operation mathematical model, operating cost is considered fuel cost and no-load cost start-up cost. Because no-load cost and start-up cost are not related to cost and power plant output, there are expressed an integer variable costs as a step function.
Study on Establishing Investment Mathematical Models for Each Application ESS Optimal Capacity in Nationwide Perspective
Kim, Jung-Hoon ; Youn, Seok-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 979~986
DOI : 10.5370/KIEE.2016.65.6.979
At present, electric power industry around the world are being gradually changed to a new paradigm, such as electrical energy storage system, the wireless power transmission. Demand for ESS, the core technology of the new paradigm, has been growing worldwide. However, it is essential to estimate the optimal capacity of ESS facilities for frequency regulation because the benefit would be saturated in accordance with the investment moment and the increase of total invested capacity of ESS facilities. Hence, in this paper, the annual optimal mathematical investment model is proposed to estimate the optimal capacity and to establish investment plan of ESS facility for frequency regulation. The optimal mathematical investment model is newly established for each season, because the construction period is short and the operation effect for the load by seasons is different unlike previous the mathematical investment model. Additionally, the marginal operating cost is found by new mathematical operation model considering no-load cost and start-up cost as step functions improving the previous mathematical operation model. ESS optimal capacity is established by use value in use iterative methods. In this case, ESS facilities cost is used in terms of the value of the beginning of the year.
Comparative Analysis of Surface-mounted and Interior Permanent Magnet Synchronous Motor
Park, Hyung-Il ; Kim, Kwan-Ho ; Shin, Kyung-Hun ; Jang, Seok-Myeong ; Choi, Jang-Young ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 987~994
DOI : 10.5370/KIEE.2016.65.6.987
In this paper, we present a comparative analysis of surface-mounted permanent magnet synchronous motors (SPMSM) and interior permanent magnet synchronous motors (IPMSM). First, we use 2D finite element analysis (FEA) to analyze models satisfying the same rated conditions according to the torque-speed curve characteristics, which are determined from the operating conditions. Next, we manufacture an SPMSM and IPMSM having good performances from an electromagnetic perspective based on analysis results, namely the cogging torque, torque ripple, and efficiency. We analyze both of the manufactured machines when they are connected back-to-back and when they are used as a motor and a generator, respectively. The motor is driven by a commercial inverter and the generator is connected to a three-phase resistance load bank. Finally, based on experimental results, which include the total harmonic distortion (THD) of the back electro-motive force (EMF), cogging torque, efficiency, and mass, we determine the motor that is most suitable under requirements.
Technology Trends to High Efficiency Motors : Focused on Induction Motor
Jang, Kibong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 995~1000
DOI : 10.5370/KIEE.2016.65.6.995
Minimum Energy Performance Standard(MEPS) has been adapted in Korea since 2008. For at least 37 kW, IE3 efficiency class motors are now mandatory in Korea. IE4 level regulation is expected in a few years. Foreign companies are already selling IE4 class motors in the market, and the discussions on IE5 have already started. The efficiency standard of variable speed motors is scheduled for publication shortly. Recently, discussions are now beginning to prepare for IE5 in Korea. In this paper, author reviews the policies associated with a high efficent electric motors by reference to both domestic and international standards, and reviews the research direction to prepare for IE5.
Optimization of Lace Tube with Gray Theory and Design of Experiment
Jeong, Ilkab ; Lee, Dongmyung ; Lee, Sangbeom ; Lim, Jintaek ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1001~1006
DOI : 10.5370/KIEE.2016.65.6.1001
As consumption of energy is increasing rapidly, energy saving is emphasized in nowadays. Thermal power plant occupies a large proportion in various type of power plant. Major causes of decreased power generation efficiency on thermal power stations is deposition of fly ash. Soot Blower is a facility to remove the ash which is deposited outside of tube by steam blowing on boiler. Residual stream which caused by lance tube in soot blower cannot be discharged steam effectively in lance tube causes reducing the thickness of lance tube. On the contrary, increasing discharge ratio of steam, lance tube cannot sustain proper pressure to remove ash on tube. This study suggests increasing discharge ratio of steam with proper pressure to remove ash on tube by optimization on shape of lance tube nozzle. To optimize shape of nozzle, discharge ratio and maximum blowing pressure on nozzle is selected as object functions. Diameter of nozzle, distance between nozzles, angle of nozzle and gap between nozzle is selected as design parameters. Then the design of experiment (DOE) with an orthogonal array is performed to analyze the effect of design parameters. And grey relational analysis and analysis of mean (ANOM) is performed to optimize shape of lance tube.
Analysis of Soft Start-up Characteristics of the Induction Motor Considering the Firing Angle
Kim, Jong-Gyeum ; Park, Young-Jeen ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1007~1012
DOI : 10.5370/KIEE.2016.65.6.1007
Induction motors are used widely in driving load of a fluid, such as a pump or a fan in the industry. Induction motor has been generated the voltage drop by the occurrence of a high current during startup. In addition, high start-up current can act as a mechanical stress on the shaft of the motor. So there is need a way to reduce the starting current. Soft start method is one of the many ways to reduce the starting current. This method uses silicon-controlled rectifiers(SCRs) for varying value of the voltage applied to the motor. There is a case for fixing or changing the thyristor firing angle to adjust the magnitude of the voltage. Starting power factor of induction motor is very low compared to the normal operation. Soft starting with the firing angle fixed needs to be considered a low power factor at startup. In this study, we compared the direct start characteristics and soft start characteristics considering the low power factor at the time of start-up. It was possible to confirm that the starting current and the voltage drop is present differently according to the firing angle.
The Comparative Analysis of 2-Phase Inverter Topologies for 2-Phase Induction Motor
Kim, Dong-Ki ; Yoon, Duck-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1013~1018
DOI : 10.5370/KIEE.2016.65.6.1013
In this paper, three kinds of the inverter topologies for the variable speed drive of 2-phase induction motor are compared and analyzed. The 2-phase inverters are classified into 2-leg, 3-leg, and 4-leg types depending on the number of power switching devices. And they use the output voltage vectors of the different forms according to the inverter topologies. Based on the comparative analyzed results, the effective values of output voltage have been defined by the linear modulation range. Therefore, the motor design guideline is proposed in order to decide a rated voltage of 2-phase induction motor according to the inverter topologies. Also, the computer simulations are carried out to verify the output voltage and current characteristics of each inverter topology.
Parallel Reduced-Order Square-Root Unscented Kalman Filter for State Estimation of Sensorless Permanent-Magnet Synchronous Motor
Moon, Cheol ; Kwon, Young-Ahn ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1019~1025
DOI : 10.5370/KIEE.2016.65.6.1019
This paper proposes a parallel reduced-order square-root unscented Kalman filter for state estimation of a sensorless permanent-magnet synchronous motor. The appearance of an unscented Kalman filter is caused by the linearization process error between a real system and classical Kalman model. The unscented transformation can make a more accurate Kalman model. However, the complexity is its main drawback. This paper investigates the design and implementation of the proposed filter with Potter and Carlson square-root form. The proposed parallel reduced-order square-root unscented Kalman filter reduces memory and code size, and improves numerical computation. And the performance is not significantly different from the unscented Kalman filter. The experimentation is performed for the verification of the proposed filter.
A Study on the Partial Discharge Resistance Properties of Epoxy/Micro/Nano Alumina Composites
Park, Jae-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1026~1031
DOI : 10.5370/KIEE.2016.65.6.1026
Neat Epoxy, nano alumina composites, micro alumina composites and multi-nano alumina composites were prepared and experiment were performed to measure their partial discharge resistant characteristics. The partial discharge resistance obtained for the microcomposites, nanocomposites and multi-nanocomposites are compared with those of unfilled epoxy and with GDE amount for surface modifier. It was observed that compare multi-nano alumina composites to micro alumina composites, the partial discharge resistance to degradation gets improved considerably. The improvement in the degradation resistance is attributed to the interface intension between the nano alumina composites and GDE, micro alumina and epoxy neat.
Isolation Enhancement by the Non-connected Ground Structure for the Mobile Phone MIMO Antenna
Jo, Young-Sang ; Son, Tae-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1032~1037
DOI : 10.5370/KIEE.2016.65.6.1032
In this paper, the method of isolation enhancement for the mobile phone MIMO antenna of LTE class 40(2300~2400MHz) was studied. Design of MIMO antenna was based on the hybrid antenna that operates both a monopole and an IFA(Inverted F Antenna). A structure for the isolation enhancement which controls induced electric field on the ground plane is located between MIMO antenna, and was not connected with the ground but apart 0.3mm. A MIMO antenna that operates on class 3~40(1710~2400MHz) of LTE service bands and a structure for the isolation enhancement at the class 10 band were designed. VSWR measurement of implemented antenna on the FR4 board showed within 3:1 at entire design bands, and isolation between antennas at the class 40 band was less than -30dB. Isolation was enhanced more than 20dB by the studied structure. ECC(Envelope Correlation Coefficient) for MIMO performance was under 0.1, and antenna average gain and efficiency measured in the anechoic chamber were -4.28~-1.40dBi and 37.32~72.36% respectively.
Design of SDINS Rapid Initial Alignment Technique Robust to the Pyro-shock in Multi-Launch Rocket System
Lee, Hyung-Sub ; Han, Kyung-Jun ; Lee, Sang-Woo ; Yu, Myeong-Jong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1038~1044
DOI : 10.5370/KIEE.2016.65.6.1038
In this paper, a SDINS(Strapdown Inertial Navigation System) rapid initial alignment technique robust to the pyro-shock in multi-launch rocket system is proposed. The proposed method consists of three steps. Firth, transfer alignment is performed to estimate misalignment between MINS(Master INS) and SINS(Slave INS), and the estimated misalignment is written in the memory when transfer alignment is completed. Next, the pre-filtering process is performed to get rid of the acceleration error induced by launcher vibration. Finally, the horizontal alignment is performed to compensate misalignment variation caused by pyro-shock. We verified the performance of the proposed alignment method comparing with the conventional transfer alignment method. The simulation shows that the proposed initial alignment technique improves alignment performance.
Design of the Electromagnet of Maglev using Optimization Algorithm Based on Bacterial Survival Strategies
Cho, Jae-Hoon ; Kim, Young-Tae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1045~1051
DOI : 10.5370/KIEE.2016.65.6.1045
This paper introduces a new optimal design method using a bacterial survival strategies for a ectromagnet of Maglev transportation vehicle. Usually, an electromagnetic suspension which has more advantages than electro dynamic suspension is used in Maglev systems. However, the structural constraints must be considered in the optimal design of an electromagnet for electromagnetic suspend system. In this paper, the optimal design method of a electromagnet based on a bacterial survival strategies optimization algorithm to design the electromagnet satisfying the structural constraints. The effectiveness of the proposed method was verified by Matlab simulations and the simulation results show that the proposed method is more efficient than conventional methods.
Clustered Segment Index Scheme for P2P VOD Service on Virtual Mesh Overlay Network
Lim, Pheng-Un ; Choi, Hwang-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1052~1059
DOI : 10.5370/KIEE.2016.65.6.1052
Video-on-Demand(VoD) is one of the most popular media streaming which attracted many researchers` attention. VMesh is one of the most cited works in the field of the VoD system. VMesh is proposed to solve the problem of random seeking functionality. However, a large number of the DHT(Distributed Hash Table) searches in VMesh is sill the main problem which needs to be solved. In order to reduce the number of the DHT searches, the clustered segment index(CSI) scheme is proposed. In this scheme, the video segments are divided into clusters. The segment information of the video segments, which are clustered into the same cluster, are stored in the same clustered segment index that can be searched by using the hash key. Each peer also can request the required segments by using this clustered segment index. The experiment results show that the number of the DHT searches in the proposed scheme is less than that of VMesh even in case of peers leave and join the network or peers perform the fast forward/backward operations.
Design of Fingerprints Identification Based on RBFNN Using Image Processing Techniques
Bae, Jong-Soo ; Oh, Sung-Kwun ; Kim, Hyun-Ki ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1060~1069
DOI : 10.5370/KIEE.2016.65.6.1060
In this paper, we introduce the fingerprint recognition system based on Radial Basis Function Neural Network(RBFNN). Fingerprints are classified as four types(Whole, Arch, Right roof, Left roof). The preprocessing methods such as fast fourier transform, normalization, calculation of ridge`s direction, filtering with gabor filter, binarization and rotation algorithm, are used in order to extract the features on fingerprint images and then those features are considered as the inputs of the network. RBFNN uses Fuzzy C-Means(FCM) clustering in the hidden layer and polynomial functions such as linear, quadratic, and modified quadratic are defined as connection weights of the network. Particle Swarm Optimization (PSO) algorithm optimizes a number of essential parameters needed to improve the accuracy of RBFNN. Those optimized parameters include the number of clusters and the fuzzification coefficient used in the FCM algorithm, and the orders of polynomial of networks. The performance evaluation of the proposed fingerprint recognition system is illustrated with the use of fingerprint data sets that are collected through Anguli program.
Design of Incremental FCM-based Recursive RBF Neural Networks Pattern Classifier for Big Data Processing
Lee, Seung-Cheol ; Oh, Sung-Kwun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1070~1079
DOI : 10.5370/KIEE.2016.65.6.1070
In this paper, the design of recursive radial basis function neural networks based on incremental fuzzy c-means is introduced for processing the big data. Radial basis function neural networks consist of condition, conclusion and inference phase. Gaussian function is generally used as the activation function of the condition phase, but in this study, incremental fuzzy clustering is considered for the activation function of radial basis function neural networks, which could effectively do big data processing. In the conclusion phase, the connection weights of networks are given as the linear function. And then the connection weights are calculated by recursive least square estimation. In the inference phase, a final output is obtained by fuzzy inference method. Machine Learning datasets are employed to demonstrate the superiority of the proposed classifier, and their results are described from the viewpoint of the algorithm complexity and performance index.
Channel Allocation Scheme considering Inter-Link Interference for Cognitive Radio Networks
Kwon, Young-Min ; Park, Hyung-Kun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1080~1082
DOI : 10.5370/KIEE.2016.65.6.1080
In a multi-hop CR (Cognitive Radio) network, each node find a path to destination node through several links. If links have the same frequency channel, there can be a serious interference among the links and it can reduce the network capacity. In multi-channel CR networks, each channel has different capacity according to the inter-link interference, and each channel has different traffic properties of primary users. In this paper, we propose channel scheduling scheme to minimize channel interferences and collision with primary users. Simulation results show the improvement of channel capacity and collision rate with primary users.
UHF Sensor Development for Partial Discharge Exclusively for Measurement in 25.8kV GIS
Choi, Mun-Gyu ; Cha, Hanju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1083~1088
DOI : 10.5370/KIEE.2016.65.6.1083
25.8kV GIS part generated by sensors to measure contact an inflow of noise depending on the extent of the measured discharge occurs often not easy. Partial discharge signal measurement sensor suitable for developing a more useful measurements at the scene to this, partial discharge waveform analysis developed a sensor, and to utilize forSensor on the development of the most important is VSWR decided to (voltage standing wave ratio) voltage standing-wave ratio less than 1.5 and decided less than at the full spectrum bands that are measured, this time Return loss, as measured value by absolute criteria 14.0 dB produced the sensor, designed to or more. UHF 1.5~0.5 GHz bandwidth spectrum to be measured in GIS. UHF bands were designed to be able to measure the best signal. Recently, 25.8kV GIS production company has been increasing variety of GIS were made open spacer in partial discharge in accordance with the not very easy to detect the signal. The sensor is designed height of four cm external spacer is attachment GIS in an influx of outside noise measurement, and be so manufactured as to facilitate the least we`ve done. Also, since partial discharge which occur can measure the frequency of the 170kV GIS external partial-discharge signals that occur at the scene of insulation applied to the spacer. Features, and also derived good results using global positioning. Also measured discharge point about sensors that are stable and the reliability of the development and local substation equipment failure occurring signal analysis through the discharge for the prevention of widely. There should be to believe that used.
A Study on The Bang-Bang Controller Applied to Electrical Vehicle
Bae, Jong-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1089~1094
DOI : 10.5370/KIEE.2016.65.6.1089
In order to establish the robust controller design technique of series wound motor driver system. This paper proposes a method of Bang-Bang controller using a series wound motor driver system under improperly variable load. A Bang-Bang controller structure is simpler than the structure of PID plus Bang-Bang controller. This paper shows that a general 8 bits microprocessor is used efficiently implementing such an algorithm. The calculation time of software is extremely small when compared with conventional PID plus Bang-Bang controller. Both nonlinear operating characteristics of digital switching elements and describing function methods are used for the analysis and synthesis. Real time implementation of Bang-Bang controller is achieved. Concept design strategy of the control and PWM waveform generation algorithms are presented in the paper.
A study on interoperability and applicability of the Korean Radio based Train Control System(KRTCS)
Kang, Yong-Sam ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1095~1102
DOI : 10.5370/KIEE.2016.65.6.1095
A TCS(Train Control System) is the core facility to ensure the safety and efficiency of train operations, it is difficult to have interoperability between the TCS suppliers. To ensure the interoperability between TCSs, there is a need for definition, validation and standardization on the system configuration, the functions of subsystems, the interface between subsystems an the system protocol. In this paper, we analyzed the completeness of the KRTCS(Korean Radio based Train Control System) specification, derived supplements what you need to apply the KRTCS specification to new urban lines.
A Study on Performance Diagnosis of the Pulley Type Automatic Tensioning Device and Improvement of Maintenance
Park, Hyun ; Lho, Young Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1103~1107
DOI : 10.5370/KIEE.2016.65.6.1103
The automatic tensioning device of the catenary system constantly maintains the tension of the trolley wire by absorbing the variations due to the elasticity of the line caused by temperature variation. The tension plays an important role in affecting the electric motorcar operation directly. This paper suggests the methodology of the life cycle extension and the maintenance of the automatic tensioning device by means of performance diagnosis of the pulley type automatic tensioning device which has been commonly used for the electric railway system. Through conducting performance diagnosis and comparative test for the wornout pulley type automatic tensioning device by replacing the components such as the bearing and the bearing shaft without replacing all the assembly, the tensioning device is analyzed whether it is properly functioned. Provided that the maintenance regulation is reinforced so as to implement the bearing replacement through periodical precise inspection along with random check-up inspection which is now carried out by the operating organizations, it is ensured that the life cycle extension and the reduction of maintenance cost of the tensioning device could be achieved.
A Study on DC Offset Removal using Low-Pass Filter in AT Feeder System for Electric Railway
Lee, Hwan ; Jung, No-Geon ; Kim, Jae-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 65, issue 6, 2016, Pages 1108~1114
DOI : 10.5370/KIEE.2016.65.6.1108
The cause of failure in the AT feeding system is divided into grounding, short-circuit of feeding circuit and internal faults of the railway substation. Since the fault current is very high, real-time current is detected and the failure must be immediately removed. In this paper, a new DC offset elimination filter that can remove component to decrease in the form of exponential function using low-pass filter was proposed in order to extract the fundamental wave from distorted fault current. In order to confirm the performance of the proposed filter method, AT feeder system was modelled by simulation tool and simulations were performed under various conditions such as fault location, fault resistance and fault voltage phase angle in case of trolley-rail short-circuit fault. When applying the proposed DC-offset removal method, it can be seen that the phase delay and gain error did not appear.