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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of The Korean Institute of Electrical Engineers
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 60, Issue 12 - Dec 2011
Volume 60, Issue 11 - Nov 2011
Volume 60, Issue 10 - Oct 2011
Volume 60, Issue 9 - Sep 2011
Volume 60, Issue 8 - Aug 2011
Volume 60, Issue 7 - Jul 2011
Volume 60, Issue 6 - Jun 2011
Volume 60, Issue 5 - May 2011
Volume 60, Issue 4 - Apr 2011
Volume 60, Issue 3 - Mar 2011
Volume 60, Issue 2 - Feb 2011
Volume 60, Issue 1 - Jan 2011
Selecting the target year
A Study on the Simulation Methodology of Home Appliance Control and Load Experiment for the Development of All-electric House Load Models
Hwang, Sung-Wook ; Kim, Kang-Sik ; Nah, Hwan-Seon ; Park, Hyeon-Jeong ; Kim, Jung-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1451~1459
DOI : 10.5370/KIEE.2011.60.8.1451
Recently, low energy houses have become an essential issue globally and various subsidy programs are ongoing to penetrate. All-electric houses which are another type of low energy houses or zero carbon houses are being developed. These houses consider new & renewable energy and demand side management programs in the construction and the diffusion process because these programs are essential policies to use energy resources reasonably. This paper shows a simulation methodology to control home appliances in all-electric houses considering the electricity consumption pattern of residents. The simulation is a first step to estimate energy saving of the house in a practical manner.
Development of the Algorithm for Discriminating Faults from Variation using Wavelet Transform
Seo, Hun-Chul ; Lee, Soon-Jeong ; Kim, Chul-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1460~1466
DOI : 10.5370/KIEE.2011.60.8.1460
This paper proposes the algorithm for discriminating faults from the variation due to the operation of non-linear components to prevent the mal-operation of protection relay in the distribution system. An IEEE 13 node test feeder is modeled to analyze the characteristics of the fault and each variation using EMTP-RV. Simulations with various operating conditions of transformers, non-linear loads, and unbalanced loads are performed using the test feeder model. Based on simulation results, the wavelet transform is adopted to analyze the current waveforms from the faults and variations to find out the differences between them and the algorithm for discriminating faults from the variation is proposed. The proposed algorithm is verified by using the current waveforms simulated in the KEPCO`s distiribution system and IEEE 13 node test feeder.
Optimal Operation Scheme of MicroGrid System based on Renewable Energy Resources
Rhee, Sang-Bong ; Kim, Kyu-Ho ; Lee, Sang-Geun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1467~1472
DOI : 10.5370/KIEE.2011.60.8.1467
This paper presents an optimal operation of microgrid systems and considering a tie-lines capacities that concerned each grid. The microgrid system consists of a wind turbine, a diesel generator, and a fuel cell. An one day load profile and wind resource for wind turbine generator were used for the study. For the grid interconnection, tie-line capacities were applied as constraints. The capacity constraints of tie-lines in production cost analysis are very important issues in the operation and planning of microgrid. In optimization, the Harmony Search (HS) algorithm is used for solving the problem of microgrid system operation which a various generation resources are available to meet the customer load demand with minimum operating cost. The application of HS algorithm to optimal operation of microgrid proves its effectiveness to determine optimally the generating resources without any differences of load mismatch.
Development of CIMToolkit based on IEC 61970/61968 for System IntegrationA Study on the Design of Testable CAM using MTA Code
Heo, Dong-Uk ; Seo, Jeong-Il ; Han, Ju-Hyun ; Son, Sung-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1473~1478
DOI : 10.5370/KIEE.2011.60.8.1473
Since IT technology was combined with the power system, many systems and applications have been developed and also Integration between systems has been followed in order to meet much higher level. Futher more to reduce the cost of system integration there were needs standardized data model and interfaces among systems or applications. so IEC has reached to establish standard interfaces and data model. Most of the current distribution automation system in South Korea, each operating independently in an enclosed environment, are managed. As time goes by, however, because of resons that the system is increasingly complex by implenting new kind of power source and demand for electricity is rapidly increasing, it became difficult to predict with a independent data from one system. In this paper, In order to apply common infomation model and standard interfaces which are defined in IEC 61970/61968 to the exisiting distribution automation system in KEPCO, several software tools and applications which have been created will be introduced.
Transmission-Line Wiring Midair Protection Net & Installation Methods
Hwang, Chi-Young ; Back, Byoung-Chul ; Seo, Min-Geun ; Kim, Young-Hwa ; Won, Jea-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1479~1484
DOI : 10.5370/KIEE.2011.60.8.1479
The existing leg-rest for transmission line construction was established on the ground as a structure. As a result of that, it caused some problems such as, a tremendous forest damage, excessive construction costs and the long time of construction period. In order to solve these problems, we suggest the protective net for an air installation. It is a new method of construction which has a dielectric strength with a light-weight and high-strength. And it`s not influenced by a geographical feature. This excellent method doesn`t affect a forest and can reduce tremendously the construction cost and period.
Optimal Operation Methods of Protection Devices in Distribution Systems with PV Systems
Kim, Byeon-Gi ; Park, Jae-Beom ; You, Kyeong-Sang ; Rho, Dae-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1485~1491
DOI : 10.5370/KIEE.2011.60.8.1485
This paper deals with the technical problems for the protection devices, by simulating test facilities of protection coordination for Photovoltaic systems. In order to analyze the operation characteristics for the protection devices in the case that the Photovoltaic systems with bi-directional power supply are located in the feeder, this paper proposes the test facilities composed of model distribution system, protection device and model Photovoltaic systems. By performing the simulation for operation characteristics for the protection devices based on the test facilities, this paper presents the malfunction mechanism for the protection devices. The test results show that this paper is practical and effective for the technical guideline for the Photovoltaic systems.
Frequency Estimation Method using Recursive Discrete Wavelet Transform for Fault Disturbance Recorder
Park, Chul-Won ; Ban, Yu-Hyeon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1492~1501
DOI : 10.5370/KIEE.2011.60.8.1492
A wide-area protection intelligent technique has been used to improve a reliability in power systems and to prevent a blackout. Nowadays, voltage and current phasor estimation has been executed by GPS-based synchronized PMU, which has become an important way of wide-area blackout protection for the prevention of expending faults in power systems. As this technique has the difficulties in collecting and sharing of information, there have been used a FNET method for the wide-area intelligent protection. This technique is very useful for the prediction of the inception fault and for the prevention of fault propagation with accurate monitoring frequency and frequency deviation. It consists of FDRs and IMS. It is well known that FNET can detect the dynamic behavior of system and obtain the real-time frequency information. Therefore, FDRs must adopt a optimal frequency estimation method that is robust to noise and fault. In this paper, we present comparative studies for the frequency estimation method using IRDWT(improved recursive discrete wavelet transform), for the frequency estimation method using FRDWT(fast recursive discrete wavelet transform). we used the Republic of Korea 345kV power system modeling data by EMTP-RV. The user-defined arbitrary waveforms were used in order to evaluate the performance of the proposed two kinds of RDWT. Also, the frequency variation data in various range, both large range and small range, were used for simulation. The simulation results showed that the proposed frequency estimation technique using FRDWT can be the optimal frequency measurement method applied to FDRs.
Characteristic Analysis of IPMSM for Electric Vehicle Propulsion With Variable Operating Condition Based on Numerical Analysis
Im, Chae-Young ; Jung, Sang-Yong ; Lee, Cheol-Gyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1502~1509
DOI : 10.5370/KIEE.2011.60.8.1502
This Paper presents characteristic analysis in terms of interior permanent magnet synchronous motor for electric vehicle propulsion using numerical analysis. Torque ripple analysis, thermal analysis, demagnetization analysis of permanent magnet and mechanical stress analysis with variable operating condition are presented. According to these characteristic analysis, both the performance of motor and possible problems during the operation are examined thoroughly in advance.
A Study on the Parameters Estimation of Electro-Hydraulic Servo Systems Using RMSM
Kim, Byeong-Woo ; Hur, Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1510~1514
DOI : 10.5370/KIEE.2011.60.8.1510
In this paper, linear discrete model of the electro-hydraulic servo system are made for parameters estimation. The parameters of electro-hydraulic servo system are estimated using the recursive least square method. Persistent excitation conditions are studied in order to estimate parameters of electro-hydraulic servo system to real values and parameters estimation affections are studied due to the forgetting factors variation. As the results, An parameter estimation method has been synthesized for minimizing the error between reference and error.
Output Voltage Control of Z-Source Inverter by the Detection of the Input DC Voltage and Z-Network Capacitor Voltage
Kim, Se-Jin ; Jung, Young-Gook ; Lim, Young-Cheol ; Choi, Joon-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1515~1522
DOI : 10.5370/KIEE.2011.60.8.1515
This paper proposes the algorithm for the output AC voltage control of Z-source inverter by the detection of the input DC voltage and Z-network capacitor voltage. The actual modulation index of the proposed method is detected by the capacitor voltage in Z-network and input DC voltage of three-phase Z-source inverter. Control modulation index for the output voltage control is calculated by the detected actual modulation index and reference modulation index. And, calculated control modulation index is applied to the modified space vector modulation (SVM) for control the output voltage of Z-source inverter. To verify the validity of the proposed method, PSIM simulation was achieved and a DSP controlled 1[kW] three-phase Z-source inverter was producted. The simulation and experiment were performed under the condition that the load was changed in case of the constant input DC voltage and the input DC voltage was changed in case of the load was constant. As a result, we could know that the output phase voltage of Z-source inverter followed to the reference voltage 70[VRMS] despite the load or the input DC voltage were suddenly changed.
Buck-Type Charging Method for Loss Reduction of Multi-Function Inverter
Kim, Dong-Hee ; Woo, Dong-Gyun ; Lee, Byoung-Kuk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1523~1528
DOI : 10.5370/KIEE.2011.60.8.1523
This paper proposes buck-type charging method using motor inductance, 3-phase inverter and bi-directional converter without an additional charger in plug-in hybrid electric vehicles. The proposed system has advantages over the conventional system such as high charging efficiency, high power factor, and low total harmonic distortion. The validity of each methods are verified by theoretical analysis and simulation.
Efficiency Analysis Solar Cell of the Dynamic Boat`s by SPA
Han, Jong-Ho ; Lee, Jang-Myung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1529~1536
DOI : 10.5370/KIEE.2011.60.8.1529
Recently, worldwide government policy is pursuing saving energy and preservation. add to this, the solar cells are getting the spotlight nonpolluting energy source, using a variety of products for solar cell. in this paper, we`ll make solar tracking system for suitable of dynamic boat. we knew that general boats are using fixed solar cell, it`s first time to use tracking system of solar cells for boats so it is hard to application. To solve this problem in this paper we use to a magnetic compass and GPS for suitable solar tracking system of dynamic movement and to analyze fixed and tracking solar system. frist. solar tracking device is designed two-axis control system. one-axis control system is taken a magnetic compass for making efficiency defence solar tracking sensor, two-axis control system apply GPS latitude and longitude data for SPA(Solar position algorithm) so we know the azimuth and altitude. it analyze data value of accuracy comparison from result. so the proposed algorithm confirm to have validity.
Diagnosis Method of Output Power Lowering of PV System by Using Kalman Filter Algorithm
Kang, Byung-Kwan ; Kim, Seung-Tak ; Lee, Hyun-Gu ; Bae, Sun-Ho ; Park, Jung-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1537~1546
DOI : 10.5370/KIEE.2011.60.8.1537
The photovoltaic(PV) generation system have recently become widely used to solve the environmental problems and running out of fossil fuels. However, the study on maintenance is inadequate for PV system. This paper proposes the novel diagnosis method of output power decline to maintain the normal output performance of PV array. The diagnosis method used the proportional relation of irradiation-output current(S-I) of PV array at maximum power point(MPP). And, first order polynomial using the relation is proposed to easily apply PV system. To estimate the relation in case of separation of PV array producer and diagnosis system producer. Kalman Filter algorithm is also proposed at 30.2kW grid-connected PV system. Then, the performance of diagnosis method is evaluated using the hardware tests as well as the simulation.
RMS Current Estimation Technique for Reliability Analysis of Multiple Semiconductor Interconnects
Kim, Ki-Young ; Kim, Deok-Min ; Kim, Seok-Yoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1547~1554
DOI : 10.5370/KIEE.2011.60.8.1547
As process parameters scale, interconnect width are reduced rapidly while the current flowing through interconnects does not decrease in a proportional manner. This effect increases current density in metal interconnects which may result in poor reliability. Since RMS(root-mean-square) current limits are used to evaluate self-heating and short-time stress failures caused by high-current pluses, RMS current estimation is very important to guarantee the reliability of semiconductor systems. Hence, it is critical to estimate the current limits through interconnects earlier in semiconductor design stages. The purpose of this paper is to propose a fast, yet accurate RMS current estimation technique that can offer a relatively precise estimate by using closed-form equations. The efficiency and accuracy of the proposed method have been verified through simulations using HSPICE for a vast range of interconnect parameters.
Analysis of Shorted Turns in Turbine Generator Rotor Windings
Kim, Hee-Dong ; Kim, Byeong-Rae ; Choi, Hyung-Joo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1555~1559
DOI : 10.5370/KIEE.2011.60.8.1555
Turbine generator(13.8 kV, 137.5 MW) has high bearing vibration at rotation speed. Shorted turns in generator rotor windings have strong correlation with increased field current which is thus related to increase in bearing vibration. The recurrent surge oscillograph (RSO) test is performed on the rotor winding in turbine generator to detect shorted turns. The result of the RSO test indicates that shorted turns of rotor winding are generated in two locations. The RSO test was capable of identifying the presence, number, and location of shorted turns in generator rotor windings.
Analysis on the Dielectric Characteristics of Dry Air According to Pressures for Developing an Eco-friendly High Voltage Switchgear
Nam, Seok-Ho ; Kang, Hyoung-Ku ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1560~1565
DOI : 10.5370/KIEE.2011.60.8.1560
The environmental pollution caused by green-house gases such as
has been becoming the main issue of industrial society. Many developed countries are making efforts to minimize the amount of
emission come from the operation of high voltage electrical apparatuses. As a part of these efforts, 180 countries signed the Kyoto Protocol in 1997 to cut back on their green-house gas emissions. Nowadays, the study on the development of dry air insulated switchgear (DAIS) which is known as an eco-friendly electrical apparatus is in progress. A DAIS is advantageous for minimizing the effect of impurities and enhancing the dielectric characteristics over an air insulated switchgear (AIS) by applying constant pressure to an enclosed cubicle. Therefore, a study on the electrical insulation performance of dry air as a gaseous insulation medium is conducted in this paper to substitute a gas insulated switchgear (GIS) for DAIS. As results, it is verified that the AC dielectric characteristics of dry air are similar to those of air and the lightning impulse dielectric characteristics of dry air are superior to those of air at 1bar pressure condition. However, dry air is of inferior dielectric characteristics to
at 4bar pressure condition. Finally, it is suggested that the internal pressure of DAIS should be over 4bar pressure to develop a high voltage switchgear which has similar electrical performance to a conventional GIS. Also, the empirical formulae on calculating the maximum electric field intensity at sparkover of dry air are deduced by experiments according to pressures. It is expected that these results are helpful to design and develop a high voltage electrical apparatus.
A Method of Load Impedance Optimization for High Efficiency Millimeter-wave Range 2nd Harmonic Generation
Choi, Young-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1566~1571
DOI : 10.5370/KIEE.2011.60.8.1566
The objective of this paper is to present a quantitative analysis leading to the assessment of optimum terminating impedances in the design of active frequency multipliers. A brief analysis of the basic principal of the GaAs FET frequency multiplier is presented. The analysis is outlined in bias optimization and drive power determination. Utilizing the equivalent circuit model of GaAs FET, we have simulated the optimized load impedance for the maximum output of the active frequency multipliers. The C-class and reverse C-class frequency doublers have been fabricated and the load impedances have been measured. The experimental results are in good agreement with the estimated results in the simulation with the accuracy of 90%.
Control of Electromagnetic Levitation System using ε-scaling Partial State Feedback Controller
Park, Gyu-Man ; Choi, Ho-Lim ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1572~1576
DOI : 10.5370/KIEE.2011.60.8.1572
The electromagnetic levitation(EMS) system is one of the well-known nonlinear system because of its nonlinearity and several control techniques have been proposed. We propose an
-scaling partial feedback controller for the ball position control of the EMS system. The key feature of our proposed controller is the use of the scaling factor
which provides a function of controller gain tuning along with robustness. In this paper, we show the stability analysis of our proposed controller and the convergence analysis of the state observer in terms of
-scaling factor. In addition, the experimental results show the validity of the proposed controller and improved control performance over the conventional PID controller.
Posture Stabilization Control for Mobile Robot using Marker Recognition and Hybrid Visual Servoing
Lee, Sung-Goo ; Kwon, Ji-Wook ; Hong, Suk-Kyo ; Chwa, Dong-Kyoung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1577~1585
DOI : 10.5370/KIEE.2011.60.8.1577
This paper proposes a posture stabilization control algorithm for a wheeled mobile robot using hybrid visual servo control method with a position based and an image based visual servoing (PBVS and IBVS). To overcome chattering phenomena which were shown in the previous researches using a simple switching function based on a threshold, the proposed hybrid visual servo control law introduces the fusion function based on a blending function. Then, the chattering problem and rapid motion of the mobile robot can be eliminated. Also, we consider the nonlinearity of the wheeled mobile robot unlike the previous visual servo control laws using linear control methods to improve the performances of the visual servo control law. The proposed posture stabilization control law using hybrid visual servoing is verified by a theoretical analysis and simulation and experimental results.
Synchronization of a Complex Dynamical Network with Free Coupling Matrix
Lee, Tae-Hee ; Park, Ju-H. ; Kwon, Oh-Min ; Lee, Sang-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1586~1591
DOI : 10.5370/KIEE.2011.60.8.1586
This paper considers synchronization problem of a complex dynamical network. For the problem, the virtual target node is chosen as one of nodes in the complex network and only one connection is needed between an isolate target node and virtual target node not any more connections. Moreover, our synchronization scheme does not need additional conditions and information of coupling matrix comparing with existing works. Based on Lyapunov stability theory, a design criterion for a novel adaptive feedback controller for the synchronization between the isolate target node and another nodes of the complex network is proposed. Finally, the proposed method is applied to a numerical example in order to show the effectiveness of our results.
Leader-following Approach Based Adaptive Formation Control for Mobile Robots with Unknown Parameters
Moon, Ssurey ; Park, Bong-Seok ; Choi, Yoon-Ho ; Park, Jin-Bae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1592~1598
DOI : 10.5370/KIEE.2011.60.8.1592
In this paper, a formation control method based on the leader-following approach for nonholonomic mobile robots is proposed. In the previous works, it is assumed that the followers know the leader`s velocity by means of communication. However, it is difficult that the followers correctly know the leader`s velocity due to the contamination or delay of information. Thus, in this paper, an adaptive approach based on the parameter projection algorithm is proposed to estimate the leader`s velocity. Moreover, the adaptive backstepping technique is used to compensate the effects of a dynamic model with the unknown time-invariant and time-varying parameters. From the Lyapunov stability theory, it is proved that the errors of the closed-loop system are uniformly ultimately bounded. Simulation results illustrate the effectiveness of the proposed control method.
A Study on Broadband PLC for Power IT
Kim, Yeoun-Soo ; Shin, Jae-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1599~1605
DOI : 10.5370/KIEE.2011.60.8.1599
From now on, power line communication was made use of controling using 450 kHz narrow band, but as the PLC technology developing, in the near future get to the commercial step that is broadband PLC upto 30 MHz. In this paper, analyze the possibility of moving picture transmission for adapting surveillance camera which is among of the application of PLC. To analyze characteristics of channel, estimate the noise and impedance of lab, office, home. In case of noise, there is no problem to communicate each other because of 20 ~ 50 dB gain. In case of impedance, average impedance is about 100 ohm, it satisfy standards of designing modem but because max and min values get out of expectation there are some problem to acquire fully capacity of modems. Its condition is the same as transmission of multimedia data. In this test as more packets, as more handling rate, in lab, for the case that transmit 1,518 byte as the speed of 6 Mbps handling rate is upto 100%, it means possibility of moving picture transmission as the 6 Mbps speed. For delayed time there is no relationship about transmitted packets. As a result, there is no problem about applying surveillance camera via the PLC. And more cameras can work within PLC for considering the number of transmitted frames.
Improvement of the Accuracy of Wrist Noninvasive Blood Pressure Measurement Using Multiple Bio-signals
Jung, Woon-Mo ; Sim, Myeong-Heon ; Jung, Sang-O ; Kim, Min-Yong ; Yoon, Chan-Sol ; Jung, In-Chol ; Yoon, Hyung-Ro ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1606~1616
DOI : 10.5370/KIEE.2011.60.8.1606
The blood pressure measuring equipment, which is being supplied and used most widely by being recognized convenience and accuracy now generally, is oscillometric blood pressure monitor. However, a change in blood pressure is basically influenced by diverse elements such as each individual`s physiological status and physical condition. Thus, the measurement of blood pressure, which used single element called oscillation in blood pressure of being conveyed to cuff, is not considered on physiological elements such as cardiovascular system status and blood vessel stiffness index, and on external elements, thereby being quite in error. Accordingly, this study detected diverse bio-signals and body informations in each individual as the measurement subject such as ECG, PPG, and Korotkoff Sound in order to enhance convenience and accuracy of measuring blood pressure in the complex measurement equipment, thereby having extracted regression method for compensation in error of oscillometric blood pressure measurement on the wrist, and having improved accuracy of measuring blood pressure. To verify a method of improving accuracy, the blood pressure value in each of SBP, DBP, MAP was acquired through 4-stage experimental procedure targeting totally 51 subjects. Prior to experiment, the subjects were divided into two groups such as the experimental group for extracting regression method and the control group for verifying regression method. Its error was analyzed by comparing the reference blood pressure value, which was obtained through the auscultatory method, and the oscillometric blood pressure value on the wrist. To reduce the detected error, the blood pressure compensation regression method was calculated through multiple linear regression analysis on elements of blood pressure, individual body information, PTT, HR, K-Sound PSD change. Verification was carried out on improving significance and accuracy by applying the regression method to the data of control group. In the experimental results, as a result of confirming error on the reference blood pressure value in SBP, DBP, and MAP, which were acquired through applying regression method, the results of
mmHg could be obtained. This is not only the numerical value of satisfying the sphygmomanometer reference of AAMI, but also shows the lower result than the numerical value in SBP :
mmHg, DBP :
mmHg, which is the mean error in the experimental results of Brram`s research for verifying accuracy of Omron RX-M, which shows relatively high accuracy among wrist sphygmomanometers. Thus, the blood pressure compensation could be confirmed to be made within significant level.
Development of the Circuit Breaker with Data Processing Function and Wireless-communication Function
Kim, Gi-Hyun ; Lee, Sang-Ick ; Shin, Seong-Su ; Bae, Seok-Myung ; Joo, Nam-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1617~1621
DOI : 10.5370/KIEE.2011.60.8.1617
In this paper, in order to reduce the electrical disaster such as electrical fire at traditional markets, we need to develop the circuit breaker which is able to monitor the power status of electrical equipments. Therefore, for solving the those problems, we developed the detection censor(ZCT, CT) and equipment of data analysis and transmission. The detection censor and equipment is able to monitor the electrical equipments condition(over current, leakage current, arc, etc.). We constructed Test-Bed for testing reliability of the circuit breaker and obtained certification. And we tested the over current, leakage current and arc under the normal condition. This paper will be used to the data for development an cabinet panel which is able to monitor the actual loads.
Linear Programming based Optimal Scheduling for Grid-connected Microgrid
Park, Jae-Sae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1622~1626
DOI : 10.5370/KIEE.2011.60.8.1622
Recently, interests on microgrids have been growing as clean power systems. Microgrids include small scaled distributed generation such as wind and solar power as well as diesel generators as main power sources. To operate a microgrid effectively, optimal scheduling for the microgrid is important. Especially, in the grid-connected mode, power trades between the microgrid and the power grid should be considered in optimal scheduling. In this paper, mathematic models for optimal operation of a microgrid were established based on the linear programming. In particular, the shiftable load was considered in the models to optimize it in microgrid operation. To show feasibility of the proposed models, they were applied to optimal microgrid operation and the results were discussed.
A Study on Insulation Property of White Powder Found on High Voltage Motor Stator Winding
Kong, Tae-Sik ; Kim, Hee-Dong ; Lee, Sang-Kil ; Kim, Kyeong-Yeol ; Ju, Young-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1627~1631
DOI : 10.5370/KIEE.2011.60.8.1627
During a routine inspection of a large pump motor at power plant, white powder was found on the surface of the stator end windings. Visual inspection and high voltage insulation diagnosis was performed to determine whether this motor is available. The purpose of this paper is to understand the insulation properties of white powder found on high voltage stator and to know prevention of insulation weakness.
Partial Discharge Measurement of Power Cables for Nuclear Power Plant
Ha, Che-Wung ; Ju, Kwang-Ho ; Lim, Woo-Sang ;
The Transactions of The Korean Institute of Electrical Engineers, volume 60, issue 8, 2011, Pages 1632~1638
DOI : 10.5370/KIEE.2011.60.8.1632
Electric cables are one of the most important components in a nuclear power plant since they provide the power needed to operate electrical equipment. Despite their importance, cables typically receive little attention since they are considered passive, long-lived components that have been very reliable over the years when subjected to the environmental conditions for which they were designed. The operating experience reveals that a defect of the insulator or poor construction causes the initial failure of cable. However, the number of cable failures increase with plant aging, and these cable failures are occurring within the plants` 40-year licensed period. These cable failures have resulted in plant transients, shutdown, loss of safety functions or redundancy, entries into limiting conditions for operation, and challenges for plant operators. Therefore, diagnosis of MV cable installed in NPPs has become one of the most urgent issues in recent years. In accordance with PSR, condition maintenance for cables is also continuously required. Recently, HFPD tests have been widely performed to diagnose cable in the transmission and distribution cable system. However, on-line HFPD wasn`t used in the NPPs because of the danger of plant shutdown, measurement sensitivity and application problems, etc. In this paper, HFPD measurement with portable device was performed to evaluate the integrity of the 4.16kV & 13.8kV cable lines. The test results show that HFPD is highly attractive to the diagnosis of MV cables in NPP by high detection sensitivity on-site.