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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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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 8, Issue 6 - Nov 2013
Volume 8, Issue 5 - Sep 2013
Volume 8, Issue 4 - Jul 2013
Volume 8, Issue 3 - May 2013
Volume 8, Issue 2 - Mar 2013
Volume 8, Issue 1 - Jan 2013
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Operation Strategy of Cheju AC Network Included Multi-Infeed HVDC System
Kim, Chan-Ki ; Jang, Gilsoo ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 393~401
DOI : 10.5370/JEET.2013.8.3.393
This paper deals with the operation strategy of the Cheju AC network included MIHVDC system (Multi-Infeed HVDC system). In case that where several HVDC systems are located in the vicinity of each other, there are interactions between the different HVDC systems in such network configurations. The interactions which could be generated in multi-infeed HVDC are voltage stability, power stability and inertia stability, to analyze such systems in a systematic way to ensure that there are no risks of adverse interactions is very important. The developed method until now to analyze MIHVDC interaction is extended from MAP(Maximum Available Power) method for analyzing the power stability of the single-infeed HVDC system, this method is to solve the eigenstructure using the identified factors influencing the interactions. Finally, the algorithms which are introduced in this paper, to determine the operation strategy are applied to Cheju island network which is supplied by two HVDCs.
Design and Scrutiny of Maiden PSS for Alleviation of Power System Oscillations Using RCGA and PSO Techniques
Falehi, Ali Darvish ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 402~410
DOI : 10.5370/JEET.2013.8.3.402
In this paper, a novel and robust Power System Stabilizer (PSS) is proposed as an effective approach to improve stability in electric power systems. The dynamic performance of proposed PSS has been thoroughly compared with Conventional PSS (CPSS). Both the Real Coded Genetic Algorithm (RCGA) and Particle Swarm Optimization (PSO) techniques are applied to optimum tune the parameter of both the proposed PSS and CPSS in order to damp-out power system oscillations. Due to the high sufficiency of both the RCGA and PSO techniques to solve the very non-linear objective, they have been employed for solution of the optimization problem. In order to verify the dynamic performance of these devices, different conditions of disturbance are taken into account in Single Machine Infinite Bus (SMIB) power system. Moreover, to ensure the robustness of proposed PSS in damping the power system multi-mode oscillations, a Multi Machine (MM) power system under various disturbances are considered as a test system. The results of nonlinear simulation strongly suggest that the proposed PSS significantly enhances the power system dynamic stability in both of the SMIB and MM power system as compared to CPSS.
A New Approach for Corrective and Preventive Control to Unsolvable Case in Power Networks having DERs
Dinh, Hung Nguyen ; Nguyen, Minh Y. ; Yoon, Yong Tae ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 411~420
DOI : 10.5370/JEET.2013.8.3.411
Recently, Korean system operating conditions have gradually approached an upper limit. When a contingency occurs, the power system may have no solutions. Different from the cases of bad initial guesses or the solutions are too close to the solvability boundary in which numerical methods can be applied, for unsolvable cases, the only way to restore solvability would be structure modifications. In this paper, a new approach for corrective and preventive control to such cases is proposed in two steps: (i) finding any solution regardless its feasibility; (ii) for the infeasible solution, make it feasible with additional modifications at load buses having Distributed Energy Resources. The test case built based on the peak load profile of 2008 by KEPCO including 1336 buses is analyzed. Since reactive power compensation is optimized to restore solvability, all demands are met, therefore no blackouts happen. The proposed method was integrated in the LP program designed by power21 Corporation.
Copula-ARMA Model for Multivariate Wind Speed and Its Applications in Reliability Assessment of Generating Systems
Li, Yudun ; Xie, Kaigui ; Hu, Bo ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 421~427
DOI : 10.5370/JEET.2013.8.3.421
The dependence between wind speeds in multiple wind sites has a considerable impact on the reliability of power systems containing wind energy. This paper presents a new method to generate dependent wind speed time series (WSTS) based on copulas theory. The basic feature of the method lies in separating multivariate WSTS into dependence structure and univariate time series. The dependence structure is modeled through the use of copulas, which, unlike the cross-correlation matrix, give a complete description of the joint distribution. An autoregressive moving average (ARMA) model is applied to represent univariate time series of wind speed. The proposed model is illustrated using wind data from two sites in Canada. The IEEE Reliability Test System (IEEE-RTS) is used to examine the proposed model and the impact of wind speed dependence between different wind regimes on the generation system reliability. The results confirm that the wind speed dependence has a negative effect on the generation system reliability.
Study of Optimal Location and Compensation Rate of Thyristor-Controlled Series Capacitor Considering Multi-objective Function
Shin, Hee-Sang ; Cho, Sung-Min ; Kim, Jin-Su ; Kim, Jae-Chul ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 428~435
DOI : 10.5370/JEET.2013.8.3.428
Flexible AC Transmission System (FACTS) application study on enhancing the flexibility of AC power system has continued to make progress. A thyristor-controlled series capacitor (TCSC) is a useful FACTS device that can control the power flow by adjusting line impedances and minimize the loss of power flow and voltage drop in a transmission system by adjusting line impedances. Reduced power flow loss leads to increased loadability, low system loss, and improved stability of the power system. This study proposes the optimal location and compensation rate method for TCSCs, by considering both the power system loss and voltage drop of transmission systems. The proposed method applies a multi-objective function consisting of a minimizing function for power flow loss and voltage drop. The effectiveness of the proposed method is demonstrated using IEEE 14- and a 30-bus system.
The Design of an Optimal Demand Response Controller Under Real Time Electricity Pricing
Jin, Young Gyu ; Choi, Tae-Seop ; Park, Sung Chan ; Yoon, Yong Tae ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 436~445
DOI : 10.5370/JEET.2013.8.3.436
The use of a demand response controller is necessary for electric devices to effectively respond to time varying price signals and to achieve the benefits of cost reduction. This paper describes a new formulation with the form of constrained optimization for designing an optimal demand response controller. It is demonstrated that constrained optimization is a better approach for the demand response controller, in terms of the ambiguity of device operation and the practicality of implementation of the optimal control law. This paper also proposes a design scheme to construct a demand response controller that is useful when a system controller is already adapted or optimized for the system. The design separates the demand response function from the original system control function while leaving the system control law unchanged. The proposed formulation is simulated and compared to the system with simple dynamics. The effects of the constraints, the system characteristics and the electricity price are examined further.
Centralized Adaptive Under Frequency Load Shedding Schemes for Smart Grid Using Synchronous Phase Measurement Unit
Yang, D.Y. ; Cai, G.W. ; Jiang, Y.T. ; Liu, C. ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 446~452
DOI : 10.5370/JEET.2013.8.3.446
Under frequency load shedding (UFLS) is an effective way to prevent system blackout after a serious disturbance occurs in a power system. A novel centralized adaptive under frequency load shedding (AUFLS) scheme using the synchronous phase measurement unit (PMU) is proposed in this paper. Two main stages are consisted of in the developed technique. In the first stage, the active power deficit is estimated by using the simplest expression of the generator swing equation and static load model since the frequency, voltages and their rate of change can be obtained by means of measurements in real-time from various devices such as phase measurement units. In the second stage, the UFLS schemes are adapted to the estimated magnitude based on the presented model. The effectiveness of the proposed AUFLS scheme is investigated simulating different disturbance in IEEE 10-generator 39-bus New England test system.
Impacts of Wind Power Integration on Generation Dispatch in Power Systems
Lyu, Jae-Kun ; Heo, Jae-Haeng ; Kim, Mun-Kyeom ; Park, Jong-Keun ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 453~463
DOI : 10.5370/JEET.2013.8.3.453
The probabilistic nature of renewable energy, especially wind energy, increases the needs for new forms of planning and operating with electrical power. This paper presents a novel approach for determining the short-term generation schedule for optimal operations of wind energy-integrated power systems. The proposed probabilistic security-constrained optimal power flow (P-SCOPF) considers dispatch, network, and security constraints in pre- and post-contingency states. The method considers two sources of uncertainty: power demand and wind speed. The power demand is assumed to follow a normal distribution, while the correlated wind speed is modeled by the Weibull distribution. A Monte Carlo simulation is used to choose input variables of power demand and wind speed from their probability distribution functions. Then, P-SCOPF can be applied to the input variables. This approach was tested on a modified IEEE 30-bus system with two wind farms. The results show that the proposed approach provides information on power system economics, security, and environmental parameters to enable better decision-making by system operators.
Hybrid PSO-Complex Algorithm Based Parameter Identification for a Composite Load Model
Del Castillo, Manuelito Y. Jr. ; Song, Hwachang ; Lee, Byongjun ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 464~471
DOI : 10.5370/JEET.2013.8.3.464
This paper proposes a hybrid searching algorithm based on parameter identification for power system load models. Hybrid searching was performed by the combination of particle swarm optimization (PSO) and a complex method, which enhances the convergence of solutions closer to minima and takes advantage of global searching with PSO. In this paper, the load model of interest is composed of a ZIP model and a third-order model for induction motors for stability analysis, and parameter sets are obtained that best-fit the output measurement data using the hybrid search. The origin of the hybrid method is to further apply the complex method as a local search for finding better solutions using the selected particles from the performed PSO procedure.
Measurement and Simulation of Wide-area Frequency in US Eastern Interconnected Power System
Kook, Kyung Soo ; Liu, Yilu ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 472~477
DOI : 10.5370/JEET.2013.8.3.472
An internet-based, real-time GPS synchronized wide-area power system frequency monitoring network(FNET) has been monitoring wide-area power system frequency in continuous time in the United States. This paper analyzes the FNET measurement to the verified disturbances in the US eastern interconnected power system and simulates it using the dynamic system model. By comparing the frequency measurements with its simulation results to the same disturbances in detail, this paper finds that the sequence of monitoring points to detect the frequency fluctuation caused by the disturbances is matched well in the measured data and the simulation results. The similarity comparison index is also proposed to quantify the similarity of the compared cases. The dynamic model based simulation result is expected to compensate for the lack of FNET measurement in its applications.
Designing an Emotional Intelligent Controller for IPFC to Improve the Transient Stability Based on Energy Function
Jafari, Ehsan ; Marjanian, Ali ; Solaymani, Soodabeh ; Shahgholian, Ghazanfar ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 478~489
DOI : 10.5370/JEET.2013.8.3.478
The controllability and stability of power systems can be increased by Flexible AC Transmission Devices (FACTs). One of the FACTs devices is Interline Power-Flow Controller (IPFC) by which the voltage stability, dynamic stability and transient stability of power systems can be improved. In the present paper, the convenient operation and control of IPFC for transient stability improvement are considered. Considering that the system's Lyapunov energy function is a relevant tool to study the stability affair. IPFC energy function optimization has been used in order to access the maximum of transient stability margin. In order to control IPFC, a Brain Emotional Learning Based Intelligent Controller (BELBIC) and PI controller have been used. The utilization of the new controller is based on the emotion-processing mechanism in the brain and is essentially an action selection, which is based on sensory inputs and emotional cues. This intelligent control is based on the limbic system of the mammalian brain. Simulation confirms the ability of BELBIC controller compared with conventional PI controller. The designing results have been studied by the simulation of a single-machine system with infinite bus (SMIB) and another standard 9-buses system (Anderson and Fouad, 1977).
Combined Economic and Emission Dispatch with Valve-point loading of Thermal Generators using Modified NSGA-II
Rajkumar, M. ; Mahadevan, K. ; Kannan, S. ; Baskar, S. ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 490~498
DOI : 10.5370/JEET.2013.8.3.490
This paper discusses the application of evolutionary multi-objective optimization algorithms namely Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and Modified NSGA-II (MNSGA-II) for solving the Combined Economic Emission Dispatch (CEED) problem with valve-point loading. The valve-point loading introduce ripples in the input-output characteristics of generating units and make the CEED problem as a non-smooth optimization problem. IEEE 57-bus and IEEE 118-bus systems are taken to validate its effectiveness of NSGA-II and MNSGA-II. To compare the Pareto-front obtained using NSGA-II and MNSGA-II, reference Pareto-front is generated using multiple runs of Real Coded Genetic Algorithm (RCGA) with weighted sum of objectives. Furthermore, three different performance metrics such as convergence, diversity and Inverted Generational Distance (IGD) are calculated for evaluating the closeness of obtained Pareto-fronts. Numerical results reveal that MNSGA-II algorithm performs better than NSGA-II algorithm to solve the CEED problem effectively.
Algorithm for Fault Location Estimation on Transmission Lines using Second-order Difference of a Positive Sequence Current Phasor
Yeo, Sang-Min ; Jang, Won-Hyeok ; Kim, Chul-Hwan ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 499~506
DOI : 10.5370/JEET.2013.8.3.499
The accurate estimation of a fault location is desired in distance protection schemes for transmission lines in order to selectively deactivate a faulted line. However, a typical method to estimate a fault location by calculating impedances with voltages and currents at relaying points may have errors due to various factors such as the mutual impedances of lines, fault impedances, or effects of parallel circuits. The proposed algorithm in this paper begins by extracting the fundamental phasor of the positive sequence currents from the three phase currents. The second-order difference of the phasor is then calculated based on the fundamental phasor of positive sequence currents. The traveling times of the waves generated by a fault are derived from the second-order difference of the phasor. Finally, the distance from the relaying point to the fault is estimated using the traveling times. To analyze the performance of the algorithm, a power system with EHV(Extra High Voltage) untransposed double-circuit transmission lines is modeled and simulated under various fault conditions, such as several fault types, fault locations, and fault inception angles. The results of the simulations show that the proposed algorithm has the capability to estimate the fault locations with high speed and accuracy.
Order Harmonic Compensation Method for Wind Power System Using a PR Controller
Jeong, Hae-Gwang ; Lee, Jong-Hyun ; Lee, Kyo-Beum ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 507~515
DOI : 10.5370/JEET.2013.8.3.507
This paper proposes a compensation method for the
-order harmonic of single-phase grid-connected wind power generation systems. Theoretically, a single-phase grid-connected inverter system has no choice but to cause the
-order harmonic to DC-link voltage. The reference active current is affected by the DC-link voltage. The output current from the reference active current is distorted by the
-order harmonic. The proposed method can compensate, conveniently, the reference active current with the
-order harmonic. To reduce the
-order ripple in the reference active current, proposed method takes a PR controller as a feed-forward compensator. PR controllers can implement selective harmonic compensation without excessive computational requirements; the use of these controllers simplifies the method. Both the simulation and experimental results agree well with the theoretical analysis.
An Improved Flux Observer for Sensorless Permanent Magnet Synchronous Motor Drives with Parameter Identification
Lin, Hai ; Hwang, Kyu-Yun ; Kwon, Byung-Il ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 516~523
DOI : 10.5370/JEET.2013.8.3.516
This paper investigates an improved stator flux linkage observer for sensorless permanent magnet synchronous motor (PMSM) drives using a voltage-based flux linkage model and an adaptive sliding mode variable structure. We propose a new observer design that employs an improved sliding mode reaching law to achieve better estimation accuracy. The design includes two models and two adaptive estimating laws, and we illustrate that the design is stable using the Popov hyper-stability theory. Simulation and experimental results demonstrate that the proposed estimator accurately calculates the speed, the stator flux linkage, and the resistance while overcoming the shortcomings of traditional estimators.
The Lightning Impulse Properties and Breakdown Voltage of Natural Ester Fluids Near the Pour Point
Choi, Sun-Ho ; Huh, Chang-Su ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 524~529
DOI : 10.5370/JEET.2013.8.3.524
Recently, researchers have become interested in natural ester fluids, as they are an environmentally friendly alternative to mineral oils. Natural ester fluids are a natural resource made from plants; they have higher biodegradability, flash, and fire points, and a greater permittivity compared to conventional mineral oils. However, natural ester fluids also have a higher pour point, viscosity, and water content. These characteristics can hamper circulation and impair the electrical properties of an oil-filled transformer. A large amount of data has been accumulated over the years in regards to mineral insulating oil involving dielectric breakdown voltage and lightning impulse tests. However, natural ester fluids have not had their electrical properties sufficiently characterized. In this paper, we present an investigation into the characteristics of the electrical discharge development in natural ester fluids and in an oil-filled transformer near the pour points. The experiment results show that the electrical properties decreased according to a decrease in the ambient temperature and freezing time. It was found that the pour point and water content of natural ester fluids have a significant effect on the electrical properties.
Sensorless Fuzzy Direct Torque Control for High Performance Electric Vehicle with Four In-Wheel Motors
Sekour, M'hamed ; Hartani, Kada ; Draou, Azeddine ; Allali, Ahmed ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 530~543
DOI : 10.5370/JEET.2013.8.3.530
This paper describes a control scheme of speed sensorless fuzzy direct torque control (FDTC) of permanent magnet synchronous motor for electric vehicle (EV). Electric vehicle requires fast torque response and high efficiency of the drive. Speed sensorless FDTC In-wheel PMSM drives without mechanical speed sensors at the motor shaft have the attractions of low cost, quick response and high reliability in electric vehicle application. This paper presents a new approach to estimate the speed of in-wheel electrical vehicles based on Model Reference Adaptive System (MRAS). The direct torque control suffers in low speeds due to the effect of changes in stator resistance on the flux measurements. To improve the system performance at low speeds, a PI-fuzzy resistance estimator is proposed to eliminate the error due to changes in stator resistance. High performance sensorless drive of the in-wheel motor based on MRAS with on line stator resistance tuning is established for four motorized wheels electric vehicle and the whole system is simulated by matalb/simulink. The simulation results show the effectiveness of the new control strategy. This proposed control strategy is extensively used in electric vehicle application.
Simplified Control Scheme of Unified Power Quality Conditioner based on Three-phase Three-level (NPC) inverter to Mitigate Current Source Harmonics and Compensate All Voltage Disturbances
Salim, Chennai ; Toufik, Benchouia Mohamed ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 544~558
DOI : 10.5370/JEET.2013.8.3.544
This paper proposes a simplified and efficient control scheme for Unified Power Quality Conditioner (UPQC) based on three-level (NPC) inverter capable to mitigate source current harmonics and compensate all voltage disturbances perturbations such us, voltage sags, swells, unbalances and harmonics. The UPQC is designed by the integration of series and shunt active filters (AFs) sharing a common dc bus capacitor. The dc voltage is maintained constant using proportional integral voltage controller. The shunt and series AF are designed using a three-phase three-level (NPC) inverter. The synchronous reference frame (SRF) theory is used to get the reference signals for shunt and the power reactive theory (PQ) for a series APFs. The reference signals for the shunt and series APF are derived from the control algorithm and sensed signals are injected in tow controllers to generate switching signals for series and shunt APFs. The performance of proposed UPQC system is evaluated in terms of power factor correction and mitigation of voltage, current harmonics and all voltage disturbances compensation in three-phase, three-wire power system using MATLAB-Simulink software and SimPowerSystem Toolbox. The simulation results demonstrate that the proposed UPQC system can improve the power quality at the common connection point of the non-linear load.
Improving Forecast Accuracy of Wind Speed Using Wavelet Transform and Neural Networks
Ramesh Babu, N. ; Arulmozhivarman, P. ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 559~564
DOI : 10.5370/JEET.2013.8.3.559
In this paper a new hybrid forecast method composed of wavelet transform and neural network is proposed to forecast the wind speed more accurately. In the field of wind energy research, accurate forecast of wind speed is a challenging task. This will influence the power system scheduling and the dynamic control of wind turbine. The wind data used here is measured at 15 minute time intervals. The performance is evaluated based on the metrics, namely, mean square error, mean absolute error, sum squared error of the proposed model and compared with the back propagation model. Simulation studies are carried out and it is reported that the proposed model outperforms the compared model based on the metrics used and conclusions were drawn appropriately.
Optimization of Energy Conversion Loop in Switched Reluctance Motor for Efficiency Improvement
Li, Jian ; Qu, Ronghai ; Chen, Zhichu ; Cho, Yun-Hyun ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 565~571
DOI : 10.5370/JEET.2013.8.3.565
This paper presents an effective method to improve efficiency of switched reluctance motor by optimizing energy conversion loop. A nonlinear analytical model which takes saturation account is developed to calculate inductance and flux-linkage. The flux-linkage curve is studied to calculate the co-energy increment to obtain the optimum exciting current. For a given cross-section, the exciting current at which co-energy increment is maximum was found to be constant while stack length varies. Then the energy conversion loop was optimized by varying the stack length and turns of windings. The constraints during optimization were that motor was excited by the maximum increment co-energy current and the energy in the loop was determined by rated power of motor. Dynamic finite element analysis was used to evaluate the efficiency of various models and the comparison of results shows promising effects of the proposed method. Experiment was also conducted to validate the simulation result.
Load Profile Disaggregation Method for Home Appliances Using Active Power Consumption
Park, Herie ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 572~580
DOI : 10.5370/JEET.2013.8.3.572
Power metering and monitoring system is a basic element of Smart Grid technology. This paper proposes a new Non-Intrusive Load Monitoring (NILM) method for a residential buildings sector using the measured total active power consumption. Home electrical appliances are classified by ON/OFF state models, Multi-state models, and Composite models according to their operational characteristics observed by experiments. In order to disaggregate the operation and the power consumption of each model, an algorithm which includes a switching function, a truth table matrix, and a matching process is presented. Typical profiles of each appliances and disaggregation results are shown and classified. To improve the accuracy, a Time Lagging (TL) algorithm and a Permanent-On model (PO) algorithm are additionally proposed. The method is validated as comparing the simulation results to the experimental ones with high accuracy.
Optimal Design of Low-Speed Secondary-Sheet Single-Sided Linear Induction Motor
Shiri, Abbas ; Shoulaie, Abbas ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 581~587
DOI : 10.5370/JEET.2013.8.3.581
Among different linear motors, single-sided linear induction motors have been widely used in industry due to their simplicity and low construction cost. However, these types of motors suffer from low efficiency and power factor. In this paper, an effective procedure is proposed to design single-sided linear induction motors. The designed motor is simulated in MATLAB software in order to investigate the effect of design parameters on the performance of the machine. Regarding the obtained results, the Genetic Algorithm is employed to optimize the design considering product of efficiency and power factor as objective function. The results show significant improvement of the performance. Finally, experimental results and 2D finite element method is used to validate the model parameters and the optimization results.
Study on Aging Characteristics and Chemical Composition of Hydrogenated Transformer Oil
Qian, Yi-Hua ; Huang, Yi-Bin ; Fu, Qiang ; Zhong, Zhen-Sheng ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 588~594
DOI : 10.5370/JEET.2013.8.3.588
Under the condition of Baader aging, the chemical composition variation and the influence of transformer oil aging on electrical properties such as dielectric loss factor and physic-chemical properties such as interfacial tension were studied in the aging precess. Moreover, the correlation between hydrogenated transformer oil electrical and physic-chemical properties and its chemical composition variation were also investigated. The results show that these parameters of physic-chemical and electrical properties of hydrogenated transformer oil relate to each other and have closed correlation with chemical composition.
Contact Parameter Computation and Analysis of Air Circuit Breaker with Permanent Magnet Actuator
Fang, Shuhua ; Lin, Heyun ; Ho, S.L. ; Wang, Xianbing ; Jin, Ping ; Huang, Yunkai ; Yang, Shiyou ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 595~602
DOI : 10.5370/JEET.2013.8.3.595
An air circuit breaker (ACB) with novel double-breaker contact and permanent magnet actuator (PMA) is presented. Three-dimensional (3-D) finite element method (FEM) is employed to compute the electro-dynamic repulsion forces, including the Holm force and Lorentz force, which are acting on the static and movable contacts. The electro-dynamic repulsion forces of different contact pieces are computed, illustrating there is an optimal number of contact pieces for the ACB being studied. The electro-dynamic repulsion force of each contact, which varies from the outer position to the inner position, is also computed. Finally, the contacts of the double-breaker are manufactured according to the analyzed results to validate the simulations.
Characterization of Inkjet-Printed Silver Patterns for Application to Printed Circuit Board (PCB)
Shin, Kwon-Yong ; Lee, Minsu ; Kang, Heuiseok ; Kang, Kyungtae ; Hwang, Jun Young ; Kim, Jung-Mu ; Lee, Sang-Ho ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 603~609
DOI : 10.5370/JEET.2013.8.3.603
In this paper, we describe the analysis of inkjet-printed silver (Ag) patterns on epoxy-coated substrates according to several reliability evaluation test method guidelines for conventional printed circuit boards (PCB). To prepare patterns for the reliability analysis, various regular test patterns were created by Ag inkjet printing on flame retardant 4 (FR4) and polyimide (PI) substrates coated with epoxy for each test method. We coated the substrates with an epoxy primer layer to control the surface energy during printing of the patterns. The contact angle of the ink to the coated epoxy primer was
, and its surface energy was 18.6
. Also, the substrate temperature was set at
. We were able to obtain continuous line patterns by inkjet printing with a droplet spacing of
. The reliability evaluation tests included the dielectric withstanding voltage, adhesive strength, thermal shock, pressure cooker, bending, uniformity of line-width and spacing, and high-frequency transmission loss tests.
A Novel CPW Balanced Distributed Amplifier Using Broadband Impedance-Transforming MEMS Baluns
Lee, Sanghyo ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 610~612
DOI : 10.5370/JEET.2013.8.3.610
A novel balanced distributed amplifier (DA) was proposed using novel impedance transforming MEMS baluns. The impedance transforming MEMS balun is matched to
at one input port and
at two output ports. It is based on the electric field mode-change method, thus it is strongly independent of frequency and very compact. The novel balanced DA consists of two
-matched DAs and these are combined by
baluns. Theoretically, it has two times wider bandwidth and power capability than the conventional DA. So as to verify the proposed concept, we designed and fabricated a conventional DA and the proposed one using 0.15-
GaAs pHEMT technology.
Mobile Robot Destination Generation by Tracking a Remote Controller Using a Vision-aided Inertial Navigation Algorithm
Dang, Quoc Khanh ; Suh, Young-Soo ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 613~620
DOI : 10.5370/JEET.2013.8.3.613
A new remote control algorithm for a mobile robot is proposed, where a remote controller consists of a camera and inertial sensors. Initially the relative position and orientation of a robot is estimated by capturing four circle landmarks on the plate of the robot. When the remote controller moves to point to the destination, the camera pointing trajectory is estimated using an inertial navigation algorithm. The destination is transmitted wirelessly to the robot and then the robot is controlled to move to the destination. A quick movement of the remote controller is possible since the destination is estimated using inertial sensors. Also unlike the vision only control, the robot can be out of camera's range of view.
A Design of Dynamically Simultaneous Search GA-based Fuzzy Neural Networks: Comparative Analysis and Interpretation
Park, Byoung-Jun ; Kim, Wook-Dong ; Oh, Sung-Kwun ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 621~632
DOI : 10.5370/JEET.2013.8.3.621
In this paper, we introduce advanced architectures of genetically-oriented Fuzzy Neural Networks (FNNs) based on fuzzy set and fuzzy relation and discuss a comprehensive design methodology. The proposed FNNs are based on 'if-then' rule-based networks with the extended structure of the premise and the consequence parts of the fuzzy rules. We consider two types of the FNNs topologies, called here FSNN and FRNN, depending upon the usage of inputs in the premise of fuzzy rules. Three different type of polynomials function (namely, constant, linear, and quadratic) are used to construct the consequence of the rules. In order to improve the accuracy of FNNs, the structure and the parameters are optimized by making use of genetic algorithms (GAs). We enhance the search capabilities of the GAs by introducing the dynamic variants of genetic optimization. It fully exploits the processing capabilities of the FNNs by supporting their structural and parametric optimization. To evaluate the performance of the proposed FNNs, we exploit a suite of several representative numerical examples and its experimental results are compared with those reported in the previous studies.
Temple and Maternity Ward Security using FPRS
Ambeth Kumar, V.D. ; Ramakrishnan, M. ; Jagadeesh Kannan, R. ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 633~637
DOI : 10.5370/JEET.2013.8.3.633
A wide range of applications for Foot Print Recognition System is discussed in this paper. The whole concept works under the principle that foot print is a parameter associated with biometrics that is very common as well as distinct. Its foremost application is at the government hospitals in the under developed and third world nations where there aren't the best of facilities. This system can be applied in the maternity ward of the hospitals for the identification or differentiation of the infants. Till date there has been no specialized system adopted for this purpose. The Foot Print Recognition System will overcome all the defects of any biometrics when applied here. Since the child will be very delicate for an iris scan and it will not be able to open its eyes wide or to correctly place its finger print on the sensor since the hands of a new born infant will be closed for a while. The Foot Print Recognition system can also be implemented in temples where there are cases of theft often reported. This can be used to grant access to the karpagraham of the deity by authorized users alone. These 2 applications of FPRS are discussed in this paper.
A Novel Hearability Enhancement Method for Forward-Link Multilateration Using OFDM Signal
Park, Ji-Won ; Lim, Jeong-Min ; Lee, Kyu-Jin ; Sung, Tae-Kyung ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 638~648
DOI : 10.5370/JEET.2013.8.3.638
Together with the GPS-based approach, geo-location through mobile communication networks is a key technology for location-based service. To save the cost, most geo-location system is implemented on the existed network service, which has a cellular structure. Still, multilateration is limited in cellular structure because it is difficult for the mobile terminal to acquire distance measurements from multiple base stations. This low hearability in the receiver is caused by co-channel interference and multipath environment. Therefore, hearability enhancement is necessary for multilateration under multipath and interference environment. Former time domain based hearability methods were designed for real signals. However, orthogonal frequency division multiplexing (OFDM) signal, which its usage has been increased in digital wireless communication, is a complex signal. Thus, different hearability enhancement method is needed for OFDM signals. This paper proposes a hearability enhancement method for forward-link multilateration using OFDM signals, which employ interference cancellation and multipath mitigation. A novel interference cancellation and multipath mitigation strategy for complex-valued OFDM signals is presented that has an iterative structure. Simulation results show that the proposed multilateration method provides the user's position with an accuracy of less than 80m through the mobile WiMAX cellular network in multipath environment.
Connection Frequency Buffer Aware Routing Protocol for Delay Tolerant Network
Ayub, Qaisar ; Mohd Zahid, M. Soperi ; Abdullah, Abdul Hanan ; Rashid, Sulma ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 649~657
DOI : 10.5370/JEET.2013.8.3.649
DTN flooding based routing protocol replicate the message copy to increase the delivery like hood that overloads the network resources. The probabilistic routing protocols reduce replication cost by forwarding the message to a node that holds high predictability value to meet its destination. However, the network traffic converges to high probable nodes and produce congestion that triggers the drop of previously stored messages. In this paper, we have proposed a routing protocol called as Connection frequency Buffer Aware Routing Protocol (CFBARP) that uses an adaptive method to maintain the information about the available buffer space at the receiver before message transmission. Furthermore, a frequency based method has been employed to determine the connection recurrence among nodes. The proposed strategy has performed well in terms of reducing message drop, message relay while increases the delivery probability.
A Mitigation of Multipath Ranging Error Using Non-linear Chirp Signal
Kim, Jin-Ik ; Heo, Moon-Beom ; Jee, Gyu-In ;
Journal of Electrical Engineering and Technology, volume 8, issue 3, 2013, Pages 658~665
DOI : 10.5370/JEET.2013.8.3.658
While the chirp signal is extensively used in radar and sonar systems for target decision in wireless communication systems, it has not been widely used for positioning in indoor environments. Recently, the IEEE 802.15.4a standard has adopted the chirp spread spectrum (CSS) as an underlying technique for low-power and low-complexity precise localization. Chirp signal based ranging solutions have been established and deployed but their ranging performance has not been analyzed in multipath environments. This paper presents a ranging performance analysis of a chirp signal and suggests a method to suppress multipath error by using a type of non-linear chirp signal. Multipath ranging performance is evaluated using a conventional linear chirp signal and the proposed non-linear chirp signal. We verify the feasibility of both methods using two-ray multipath model simulation. Our results demonstrate that the proposed non-linear chirp signal can successfully suppress the multipath error.