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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Electrical Engineering and Technology
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Journal DOI :
The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 7, Issue 6 - Nov 2012
Volume 7, Issue 5 - Sep 2012
Volume 7, Issue 4 - Jul 2012
Volume 7, Issue 3 - May 2012
Volume 7, Issue 2 - Mar 2012
Volume 7, Issue 1 - Jan 2012
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Measurement-based Static Load Modeling Using the PMU data Installed on the University Load
Han, Sang-Wook ; Kim, Ji-Hun ; Lee, Byong-Jun ; Song, Hwa-Chang ; Kim, Hong-Rae ; Shin, Jeong-Hoon ; Kim, Tae-Kyun ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 653~658
DOI : 10.5370/JEET.2012.7.5.653
Load modeling has a significant influence on power system analysis and control. In recent years, measurement-based load modeling has been widely practiced. In the load modeling algorithm, the model structure is determined and the parameters of the established model are estimated. For parameter estimation, least-squares optimization method is applied. The model parameters are estimated so that the error between the measured values and the predicted values is to be minimized. By introducing sliding window concept, on-line load modeling method can be performed which reflects the dynamic behaviors of loads in real-time. For the purpose of data acquisition, the measurement system including PMU is implemented in university level. In this paper, case studies are performed using real PMU data from Korea Univ. and Seoul National University of Science and Technology. The performances of modeling real and reactive power behaviors using exponential and ZIP load model are evaluated.
Comparative Analysis on Current Limiting Characteristics of Hybrid Superconducting Fault Current Limiters (SFCLs) with First Half Cycle Limiting and Non-Limiting Operations
Kim, Jin-Seok ; Lim, Sung-Hun ; Kim, Jae-Chul ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 659~663
DOI : 10.5370/JEET.2012.7.5.659
The application of large power transformer into a power distribution system was inevitable due to the increase of power demand and distributed generation. However, the decrease of the power transformer`s impedance caused the short-circuit current of the power distribution system to be increase thus, the higher short-circuit current exceeded the cut-off ratings of the protective devices such as circuit breaker. To solve these problems, several countermeasures have been proposed to protect the power system effectively from higher fault current and the superconducting fault current limiter (SFCL) has been expected to be the promising countermeasure. In spite of excellent current limiting performances of the SFCL, on the other hand, the efforts to apply the SFCL into power system has been delayed due to both the limited spaces for the SFCL`s installation and its long recovery time after the fault removal. In order to solve these problems, a hybrid SFCL, which can perform either first half cycle limiting of first half cycle non-limiting operation, has been developed by corporation of LSIS (LS Industrial System) and KEPCO (Korea Electric Power Corporation). In this paper, we tried to requirements hybrid SFCL by PSCAD/EMTDC. Simulation results of our analysis of the hybrid SFCL is that its accompanied the characteristics both the limit the fault current and quick recovery caused by the less impact from superconductor.
UPFC Control based on New IP Type Controller
Shirvani, Mojtaba ; Keyvani, Babak ; Abdollahi, Mostafa ; Memaripour, Ahmad ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 664~671
DOI : 10.5370/JEET.2012.7.5.664
This paper presents the application of Unified Power Flow Controller (UPFC) in order to simultaneous control of power flow and voltage and also damping of Low Frequency Oscillations (LFO) at a Single-Machine Infinite-Bus (SMIB) power system installed with UPFC. PI type controllers are commonly used controllers for UPFC control. But for the sake of some drawbacks of PI type controllers, the scope for finding a better control scheme still remains. In this regard, in this paper the new IP type controllers are considered as UPFC controllers. The parameters of these IP type controllers are tuned using Genetic Algorithms (GA). Also a stabilizer supplementary controller based UPFC is considered for increasing power system damping. To show the ability of IP controllers, this controller is compared with classical PI type controllers. Simulation results emphasis on the better performance of IP controller in comparison with PI controller.
Application of Lyapunov Theory and Fuzzy Logic to Control Shunt FACTS Devices for Enhancing Transient Stability in Multimachine System
Kumkratug, P. ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 672~680
DOI : 10.5370/JEET.2012.7.5.672
This paper proposes the control strategy of the shunt Flexible AC Transmission System (FACTS) devices to improve transient stability in multimachine power system. The multimachine power system has high nonlinear response after severe disturbance. The concept of Lyapunov energy function is applied to derive nonlinear control strategy and it was found that the time derivative of line voltage is not only can apply to control the shunt FACTS devices in multimachine system but also is locally measurable signal. The fuzzy logic control is also applied to overcome the uncertainty of various disturbances in multimachine power system. This paper presents the method of investigating the effect of the shunt FACTS devices on transient stability improvement. The proposed control strategy and the method of simulation are tested on the new England power system. It was found that the shunt FACTS devices based on the proposed nonlinear control strategy can improve transient stability of multimachine power system.
Application of Differential Evolution to Dynamic Economic Dispatch Problem with Transmission Losses under Various Bidding Strategies in Electricity Markets
Rampriya, B. ; Mahadevan, K. ; Kannan, S. ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 681~688
DOI : 10.5370/JEET.2012.7.5.681
This paper presents the application of Differential Evolution (DE) algorithm to obtain a solution for Bid Based Dynamic Economic Dispatch (BBDED) problem including the transmission losses and to maximize the social profit in a deregulated power system. The IEEE-30 bus test system with six generators, two customers and two trading periods are considered under various bidding strategies in a day-ahead electricity market. By matching the bids received from supplying and distributing entities, the Independent System Operator (ISO) maximize the social profit, (with the choices available). The simulation results of DE are compared with the results of Particle swarm optimization (PSO). The results demonstrate the potential of DE algorithm and show its effectiveness to solve BBDED.
Coordination Control of Voltage Between STATCOM and Reactive Power Compensation Devices in Steady-State
Park, Ji-Ho ; Baek, Young-Sik ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 689~697
DOI : 10.5370/JEET.2012.7.5.689
This paper proposes a new coordinated voltage control scheme between STATCOM (Static Synchronous Compensator) and reactive power compensation devices, such as shunt elements(shunt capacitor and shunt reactor) and ULTC(Under-Load Tap Changer) transformer in a local substation. If STATCOM and reactive power compensators are cooperatively used with well designed control algorithm, the target of the voltage control can be achieved in a suddenly changed power system. Also, keeping reactive power reserve in a STATCOM during steady-state operation is always needed to provide reactive power requirements during emergencies. This paper describes the coordinative voltage control method to keep or control the voltage of power system in an allowable range of steady-state and securing method of momentary reactive power reserve using PSS/E with Python. In the proposed method of this paper, the voltage reference of STATCOM is adjusted to keep the voltage of the most sensitive bus to the change of loads and other reactive power compensators also are settled to supply the reactive power shortage in out range of STATCOM to cope with the change of loads. As the result of simulation, it is possible to keep the load bus voltage in limited range and secure the momentary reactive power reserve in spite of broad load range condition.
Probabilistic Reliability Based Grid Expansion Planning of Power System Including Wind Turbine Generators
Cho, Kyeong-Hee ; Park, Jeong-Je ; Choi, Jae-Seok ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 698~704
DOI : 10.5370/JEET.2012.7.5.698
This paper proposes a new methodology for evaluating the probabilistic reliability based grid expansion planning of composite power system including the Wind Turbine Generators. The proposed model includes capacity limitations and uncertainties of the generators and transmission lines. It proposes to handle the uncertainties of system elements (generators, lines, transformers and wind resources of WTG, etc.) by a Composite power system Equivalent Load Duration Curve (CMELDC)-based model considering wind turbine generators (WTG). The model is derived from a nodal equivalent load duration curve based on an effective nodal load model including WTGs. Several scenarios are used to choose the optimal solution among various scenarios featuring new candidate lines. The characteristics and effectiveness of this simulation model are illustrated by case study using Jeju power system in South Korea.
Design and Analysis of Novel 12/14 Hybrid Pole Type Bearingless Switched Reluctance Motor with Short Flux Path
Xu, Zhenyao ; Zhang, Fengge ; Lee, Dong-Hee ; Ahn, Jin-Woo ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 705~713
DOI : 10.5370/JEET.2012.7.5.705
In this paper, a novel 12/14 hybrid pole type bearingless switched reluctance motor (BLSRM) with short flux path and no flux-reversal in the stator is proposed. The proposed BLSRM has separated rotating torque and suspending force poles. Because of independent characteristics between torque and suspending force poles, the torque control can be decoupled from the suspending force control. Due to the short flux path without any reversal flux, compared to the 8/10 hybrid stator pole BLSRM, the output torque is significantly improved and the air-gap is easier to control. Meanwhile, basic design principle for the proposed structure is described. To verify the proposed structure, finite element method (FEM) is employed to get characteristics of the proposed structure and 8/10 hybrid stator pole BLSRM. Based on the analysis, a prototype of the proposed BLSRM is designed and manufactured. Finally, validity of the proposed structure is verified by the experimental results.
A New Z-Source Inverter Topology with High Voltage Boost Ability
Trinh, Quoc-Nam ; Lee, Hong-Hee ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 714~723
DOI : 10.5370/JEET.2012.7.5.714
A new Z-source inverter (ZSI) topology is developed to improve voltage boost ability. The proposed topology is modified from the switched inductor topology by adding some more inductors and diodes into inductor branch to the conventional Z-source network. The modulation methods developed for the conventional ZSI can be easily utilized in the proposed ZSI. The proposed ZSI has an ability to obtain a higher voltage boost ratio compared with the conventional ZSI under the same shoot-through duty ratio. Since a smaller shoot-through duty ratio is required for high voltage boost, the proposed ZSI is able to reduce the voltage stress on Z-source capacitor and inverter-bridge. Theoretical analysis and operating principle of the proposed topology are explicitly described. In addition, the design guideline of the proposed Z-source network as well as the PWM control method to achieve the desired voltage boost factor is also analyzed in detail. The improved performances are validated by both simulation and experiment.
Simple Fuzzy PID Controllers for DC-DC Converters
Seo, K.W. ; Choi, Han-Ho ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 724~729
DOI : 10.5370/JEET.2012.7.5.724
A fuzzy PID controller design method is proposed for precise robust control of DC-DC buck converters. The PID parameters are determined reflecting on the common control engineering knowledge that transient performances can be improved if the P and I gains are big and the D gain is small at the beginning. Different from the previous fuzzy control design methods, the proposed method requires no defuzzification module and the global stability of the proposed fuzzy control system can be guaranteed. The proposed fuzzy PID controller is implemented by using a low-cost 8-bit microcontroller, and simulation and experimental results are given to demonstrate the effectiveness of the proposed method.
Back EMF Design of an AFPM Motor using PCB Winding by Quasi 3D Space Harmonic Analysis Method
Jang, Dae-Kyu ; Chang, Jung-Hwan ; Jang, Gun-Hee ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 730~735
DOI : 10.5370/JEET.2012.7.5.730
This paper presents a method to design the waveform of a back electromotive force (back EMF) of an axial flux permanent magnet (AFPM) motor using printed circuit board (PCB) windings. When the magnetization distribution of permanent magnet (PM) is given, the magnetic field in the air gap region is calculated by the quasi three dimensional (3D) space harmonic analysis (SHA) method. Once the flux density distribution in the winding region is determined, the required shape of the back EMF can be obtained by adjusting the winding distribution. This can be done by modifying the distance between patterns of PCB to control the harmonics in the winding distribution. The proposed method is verified by finite element analysis (FEA) results and it shows the usefulness of the method in eliminating a specific harmonic component in the back EMF waveform of a motor.
Battery Charging System for PHEV and EV using Single Phase AC/DC PWM Buck Converter
Lee, Jung-Hyo ; Jung, Doo-Yong ; Park, Sang-Hoon ; Lee, Taek-Kie ; Kim, Young-Ryul ; Won, Chung-Yuen ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 736~744
DOI : 10.5370/JEET.2012.7.5.736
In this paper, a battery charging system for Plug-in Hybrid Electric Vehicle (PHEV) and Electric Vehicle (EV), and operation algorithm of charging system are introduced. Also, the proposed charging system uses commercial electricity in order to charge the battery of parked PHEV and 48V battery charging system with power factor controllable single phase converter for PHEV is investigated in this paper. This research verifies the power factor control of input and the converter output controlled by the charge control algorithm through simulation and experiment.
Optimum Design of Transverse Flux Machine for High Contribution of Permanent Magnet to Torque Using Response Surface Methodology
Xie, Jia ; Kang, Do-Hyun ; Woo, Byung-Chul ; Lee, Ji-Young ; Sha, Zheng-Hui ; Zhao, Sheng-Dun ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 745~752
DOI : 10.5370/JEET.2012.7.5.745
Transverse flux machine (TFM) has been proved to be very suitable for high-torque, low-speed, and direct-drive situation in industry. But the complex structures and costly permanent magnets (PMs) are two key limitations of its wide range of applications. This paper proposes a new claw pole TFM (ACPTFM) which features an assembled claw pole stator and using the lamination steels material to overcome the complex structures. By combining response surface methodology (RSM) with design of experiment, an optimum design method is put forward to improve the PM`s contribution to the torque in order to save the PM`s amount. The optimum design results demonstrate the validity of the proposed optimum design method and the optimized model. Eventually, the finite-element analysis (FEA) calculation method, which is used in the optimization process, is verified by the experiments in a prototype.
The Optimal Design of Fractional-slot SPM to Reduce Cogging Torque and Vibration
Cho, Gyu-Won ; Jang, Woo-Sung ; Jang, Ki-Bong ; Kim, Gyu-Tak ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 753~758
DOI : 10.5370/JEET.2012.7.5.753
This paper deals with the analysis of vibration and noise sources in a modular-type SPM fractional-slot motor. To reduce cogging torque, torque ripple and unequal radial force, which are the main causes of the electromagnetic vibration, the optimal shape of notch and magnet are designed.
Microwave Hyperthermic Lipolysis Using External RF Antenna
Hwang, Joo-Sung ; Woo, Tae-Hee ; Park, Sang-Bok ; Cheon, Chang-Yul ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 759~764
DOI : 10.5370/JEET.2012.7.5.759
In this paper, we propose a microwave hyperthermic lipolysis method to reduce subcutaneous fat without skin burn using external RF antenna. Since skin is closer to the antenna and has higher conductivity compared to the fat beneath, the temperature of the skin rises higher than that of the fat when the external antenna illuminates EM energy into a body, which may cause skin burn. In order to avoid the damages on skin, a skin cooling system is employed to the external antenna. The operating frequency is set at 5.8 GHz which is one of the ISM bands, to concentrate EM power efficiently on fat and not to heat up the muscle behind the fat. The operation time and RF power level has been determined based on experimental results with pork. The feasibility of the proposed method was shown by applying the method to the rat.
Breakdown Characteristics of SF
and Liquefied SF
at Decreased Temperature
Choi, Eun-Hyeok ; Kim, Ki-Chai ; Lee, Kwang-Sik ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 765~771
DOI : 10.5370/JEET.2012.7.5.765
gas has been used as arc quenching and insulating medium for high and extra high voltage switching devices due to its high dielectric strength, its excellent arc-quenching capabilities, its high chemical stability and non toxicity. Despite of its significant contributions, the gas was classified as one of the greenhouse gas in the Kyoto Protocol. Thus, many researches are conducted to find out the replacement materials and to develop the
gas useless electrical equipment. This paper describes experiments on the temperature change-related breakdown characteristics of
) in a model GIS(Gas-Insulated Switchgear) chamber in order to show the possibility of more stable and safe usages of
gas. The breakdown characteristics are classified into three stages, namely the gas stage of
according to Paschen`s law, the coexisting stage of
gas with liquid in considerable deviation at lower temperature, and the stage of
and remaining air. The result shows that the ability of the
insulation is higher than the high-pressurized
. Moreover, it reveals that the breakdown characteristics of
are produced by bubble-formed
evaporation and bubbles caused by high electric emission and the corona. In addition, the property of dielectric breakdown of
is determined by electrode form, electrode arrangement, bubble formation and movement, arc extinguishing capacity of the media, difficulty in corona formation, and the distance between electrodes. The bubble formation and flow separation phenomena were identified for
. It provides fundamental data not only for
gas useless equipment but also for electric insulation design of high-temperature superconductor and cryogenic equipment machinery, which will be developed in future studies.
Study on Reliability of Water Absorption Diagnosis through Precise Water Absorption Test
Kim, Hee-Soo ; Bae, Yong-Chae ; Kim, Hee-Dong ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 772~777
DOI : 10.5370/JEET.2012.7.5.772
Accidents caused by water absorption in water-cooled generator stator windings often occur all over the world. The absorption into the insulator of the coolant, which is used to cool down the heat generated by stator windings during operation, leads to the deterioration of dielectric strength, and insulation breakdown. An insulation breakdown may cause not only an enormous economic loss but also a very serious grid accident that would compromise stable supply of electric power. More than 50 % of domestic generators have been in operation for more than 15 years, and water absorption tests performed on 50 water-cooled generator stator windings during a five-year planned preventive maintenance period beginning in 2006 identified water absorption problems in 10 of them, all of which required repair. Because the existing water absorption test detects this problem by utilizing stochastic methods after measuring the capacitances at the final positions of insulation breakdown, its accuracy is limited. This study demonstrates that water absorption can be more accurately diagnosed by utilizing method along with a more precise one.
Three-phase Making Test Method for Common Type Circuit Breaker
Ryu, Jung-Hyeon ; Choi, Ike-Sun ; Kim, Kern-Joong ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 778~783
DOI : 10.5370/JEET.2012.7.5.778
The synthetic short-circuit making test to adequately stress the circuit breaker has been specified as the mandatory test duty in the IEC 62271-100. The purpose of this test is to give the maximum pre-arcing energy during making operation. And this requires the making operation with symmetrical short-circuit current that is established when the breakdown between contact gap occurs near the crest of the applied voltage. Also, if the interrupting chamber of circuit breakers is designed as the type of common enclosure or the operation is made by the gang operated mechanism that three-phase contacts are operated by one common mechanism, three-phase synthetic making test is basically required. Therefore, several testing laboratories have developed and proposed their own test circuits to properly evaluate the breaker performance. With these technical backgrounds, we have developed the new alternative three-phase making circuit.
High-Performance Optical Gating in Junction Device based on Vanadium Dioxide Thin Film Grown by Sol-Gel Method
Lee, Yong-Wook ; Kim, Eung-Soo ; Shin, Bo-Sung ; Lee, Sang-Mae ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 784~788
DOI : 10.5370/JEET.2012.7.5.784
In this paper, a high-performance optical gating in a junction device based on a vanadium dioxide dioxide (
) thin film grown by a sol-gel method was experimentally demonstrated by directly illuminating the
film of the device with an infrared light at ~1554.6 nm. The threshold voltage of the fabricated device could be tuned by ~76.8 % at an illumination power of ~39.8 mW resulting in a tuning efficiency of ~1.930 %/mW, which was ~4.9 times as large as that obtained in the previous device fabricated using the
thin film deposited by a pulsed laser deposition method. The rising and falling times of the optical gating operation were measured as ~50 ms and ~200 ms, respectively, which were ~20 times as rapid as those obtained in the previous device.
Spatiotemporal Location Fingerprint Generation Using Extended Signal Propagation Model
Kim, Hee-Sung ; Li, Binghao ; Choi, Wan-Sik ; Sung, Sang-Kyung ; Lee, Hyung-Keun ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 789~796
DOI : 10.5370/JEET.2012.7.5.789
Fingerprinting is a widely used positioning technology for received signal strength (RSS) based wireless local area network (WLAN) positioning system. Though spatial RSS variation is the key factor of the positioning technology, temporal RSS variation needs to be considered for more accuracy. To deal with the spatial and temporal RSS characteristics within a unified framework, this paper proposes an extended signal propagation mode (ESPM) and a fingerprint generation method. The proposed spatiotemporal fingerprint generation method consists of two algorithms running in parallel; Kalman filtering at several measurement-sampling locations and Kriging to generate location fingerprints at dense reference locations. The two different algorithms are connected by the extended signal propagation model which describes the spatial and temporal measurement characteristics in one frame. An experiment demonstrates that the proposed method provides an improved positioning accuracy.
Performance Comparison of GPS Fault Detection and Isolation via Pseudorange Prediction Model based Test Statistics
Yoo, Jang-Sik ; Ahn, Jong-Sun ; Lee, Young-Jae ; Sung, Sang-Kyung ;
Journal of Electrical Engineering and Technology, volume 7, issue 5, 2012, Pages 797~806
DOI : 10.5370/JEET.2012.7.5.797
Fault detection and isolation (FDI) algorithms provide fault monitoring methods in GPS measurement to isolate abnormal signals from the GPS satellites or the acquired signal in receiver. In order to monitor the occurred faults, FDI generates test statistics and decides the case that is beyond a designed threshold as a fault. For such problem of fault detection and isolation, this paper presents and evaluates position domain integrity monitoring methods by formulating various pseudorange prediction methods and investigating the resulting test statistics. In particular, precise measurements like carrier phase and Doppler rate are employed under the assumption of fault free carrier signal. The presented position domain algorithm contains the following process; first a common pseudorange prediction formula is defined with the proposed variations in pseudorange differential update. Next, a threshold computation is proposed with the test statistics distribution considering the elevation angle. Then, by examining the test statistics, fault detection and isolation is done for each satellite channel. To verify the performance, simulations using the presented fault detection methods are done for an ideal and real fault case, respectively.