Showing papers in "Journal of The Korean Institute of Illuminating and Electrical Installation Engineers in 2008"

다중회귀분석법을 이용한 지역전력수요예측 알고리즘

Abstract: 본 논문은 현 배전계통계획시스템(DISPLAN)의 지역전력수요예측 알고리즘을 개선하여 다중회귀분석을 이용한 지역전력수요예측 알고리즘을 제시하였다. 지역전력수요예측 알고리즘은 예측의 정확도를 높이기 위해 지역경제와 지역인구와 과거의 판매전력량을 입력변수로 사용하였다. 사례연구로 경북의 경산시, 구미시, 김...

A Study on the Analysis on the Direct-Driven High Power Permanent Magnet Generator for Wind Turbine

Abstract: In the paper, the permanent magnet synchronous generator of 1.5[MW] output power which is driven directly without gear system is designed by conventional magnetic equivalent circuit method and analyzed by finite element method. We analyzed the characteristics of generator like no load, rated load, short circuit condition and demagnetization of permanent magnet in order to verify the design results by magnetic circuit method. The last, the analysis results of two kinds of rotor types are compared with each other. Especially the THD (total harmonic distortion) of output voltage is examined for the comparison.

차단기 실패 보호 ied의 iec 61850 시스템 성능 시험 절차서에 관한 연구

Abstract: 디지털 기술 기반의 차세대 변전시스템의 시스템 성능 검증을 위해 변전소 전력설비의 보호에 있어 가장 중요한 보호요소 중 하나인 차단기 실패 보호 IED를 대상으로 하는 IEC 61850 시스템 성능 시험 절차서를 구현하였다. 디지털 변전소에 대한 통신규격이 단일화되고 시스템이 디지털화됨에 따라 IED들은 상호 통신이 가능해지게 되었으며, 따라서 단일 IED의 전기 접점을 통해 이루어지던 예전의 시험방식에서 네트워크를 통한 시스템 차원의 시험방식으로 변화가 필요하게 되었다. 본 논문에서는 차단기 실패 보호 IED를 시스템적으로 시험할 수 있도록 UML을 이용한 성능시험절차서의 구현내용을 보여주고자 한다.

주요 한약재의 오존처리저장 특성

Abstract: 최근 한약재의 저장 중 품질 유지를 위한 다양한 방안이 검토되고 있으며, 그 방안의 하나로 한약재의 유해 세균 및 잔존 농약을 분해, 처리하여 저장하는 방법을 연구하였다. 오존발생기에 관한 선행 연구를 통해 오존이 박테리아 및 비루스에 대한 살균효과가 우수함을 확인하고, 오존을 이용하여 한약재 살균처리 및 저장(이하 OPS)에 적용하는 방법을 연구하였다. 본 연구에서는 현재 시중에 많이 유통되어 사용되고 있는 4종류의 약재를 선정하여 한약재 특성 평가를 실시하였다. 즉 오존 램프를 이용하여 한약재 살균 특성을 조사하였고 장기간 오존 저장 후 한약재의 품질 및 고유 성분이 유지되는지를 조사하기 위하여 한약재의 일반성분 및 생리활성물질의 정량분석 평가를 하였다.

국내외 건축물에 시설되는 수변전설비 지진 대책에 관한 조사 분석

Abstract: 최근 한반도 주변국인 일본, 중국 등에서 크고 작은 지진 발생으로 많은 인명 및 재산 피해를 보고 있다. 국내에서도 지진 발생 횟수가 꾸준히 증가하여 이에 대한 대책을 세우기 위해 자연재해대책법에서 지진 관련 부분을 지진 재해대책법으로 2008년 3월에 제정하여 세부시설에 대한 지진 대책 제시 및 이를 강화하고 있다. 본 논문은 지진 발생시 건축물에서 위급상황에 대한 대처 및 여러 가지 구제 활동에 필수적인 전원공급 장치인 수변전실의 전기설비 지진 대책에 관하여 국내 현황 및 문제점을 분석하였다. 또한 국외의 전기설비에 대한 내진 설계 및 시설에 관한 규정을 조사 분석하여 국내 건축물 수변전설비의 내진 설계 및 시공 방향을 제시하였다. 추후로 건축물 수변전실의 진기섣비 내진설계 방법 제시 및 그에 따른 시공의 신뢰성 검증을 위한 검사·점검 부분에 대한 연구가 필요하다고 판단된다.

Sensibility Evaluation on the Correlated Color Temperature in White LED Lighting

Abstract: The aim of this study is to investigate the sensitivity evaluation of human beings in reacting to the correlated color temperature of the optical properties of white LED lighting. For the sake of this study, white light-emitting diode modules have been fabricated their correlated color temperature have been measured, test cabinets for the sensitivity evaluation have been constructed with the white LED modules, and their sensitivity reactions on the test cabinets have been evaluated and analyzed. The sensitivity reaction has been evaluated by the semantic differential method with 15 selected questions, and the reliability and the content validity of their lighting have been analyzed to 3 factors which foe the activity as the first factor, the stability as the second one, the potency as the third one, respectively. For the data analysis on the sensitivity reaction, the dependent variable is the score of the sensitivity evaluation and the independent one is the correlated color temperature of the test module. The results of this study is as follows: In the case of the sensitive evaluation on the activity and the potency in the white LED lighting compared with the fluorescent lamp, the subjects have made higher mark on with 8,300[K], and in the factor of the stability, they have made higher mark on with 3,800[K].

An Analysis of Daylighting Performance of Light Shelf in Office Building

Abstract: The purpose of this study is to present the design guideline for an effective application of light shelf in office building. For this, the computer simulation using Daylighting System of 3Ds Studio Max was performed, and the optimal values related to design factors such as a depth, a surface reflectance and a installation angle of light shelf were obtained. Then daylighting performance of light shelf using the optimal values was analyzed, and the simulation results show that the installation of the optimal light shelf can improve a indoor lighting environment in office building.

A Novel PV Tracking System Control Considering the Power Loss with Change of Insolation

Abstract: In this paper proposes a novel tacking algorithm regarding the power loss when operating a tracking system for a rapidly changing insolation to improve the power of PV hacking system. The tracking system of sensor method used in a conventional PV power station is unable to exactly track a sun position when lacking in the intensity of radiation and has the problem is malfunction of tracking system by a rapidly changing climatic. The tracking system of program method spends too much energy on the unnecessary operation of tracking system because that is unable to adapt itself to a outside factor of climatic environment. In case of tracking an azimuth and altitude of the sun in realtime, therefore, the actual PV power is less increasing than the power of tracking system fixed a specific position. To reduce the power loss, this pap proposes a novel control algorithm of the tracking system. Also, this paper is analyzed efficiency of traditional solar tracking method and proposed method, prove validity of proposed algorithm through demonstrable study.

Characteristics Analysis of Power Capacitor with Unbalanced Voltage Operation

Abstract: In the three phase four wire system, voltage unbalance caused by the unbalanced load operation, gives rise to current unbalance and de-rates by the increase of machine`s loss and eventually enlarges power capacity and besides has a bad effect on power quality. Power capacitor has been used for the power factor correction of inductive load and the voltage stability of power system. And it uses instead of power side for magnetic excitation of induction motor. If voltage unbalance keeps up, it affects on voltage stress at the power capacitor and finally can be caused breakdown. In this paper, we analysed that voltage and current of power capacitor increases by the voltage unbalance factor and its stress is growing more and more.

High-Frequency Zero Current Soft Switching Inverter with Pulse Density Modulation for Induction Heated Roller

Abstract: This paper presents a voltage source type half-bridge series resonant high frequency (HF) inverter for induction heated fixing roller in copy machines. This high-frequency inverter works under zero current soft switching (ZCS) commutation and has wide power regulation range due to employing a pulse density modulation (PDM) scheme. Transient and steady state operating modes of the inverter are presented in this paper together with its PDM-based power regulation system Experimental operating performances of the developed HF-ZCS inverter as well as power losses and actual efficiency are discussed and compared with computer simulation results.

교류배전시스템과 직류배전시스템이 적용된 idc 전력효율 비교연구

Abstract: 급격한 IT 산업 발전의 산물인 인터넷데이터센터(IDC)는 서버 시스템이 집적된 고밀도 디지털 부하로 구성되는 특징을 가지고 있다. IDC의 디지털 부하 특성을 고려하여 직류배전시스템을 도입하는 경우 전력 변환 체계의 단순화로 효율 향상의 가능성이 일부 제기되어 왔으나, 국내 IDC 환경에서의 효율성이 검증된 사례는 없었다. 본 논문에서는 교류배전방식을 적용한 KT 분당 IDC와 직류배전방식을 적용한 KT 남수원 IDC의 전력 효율을 비교 분석함으로써 국내 IDC 배전체계의 직류화에 따른 효율 개선 효과를 제시하였다. DC 48[V]를 배전하였을 때 직류배전 방식의 효율이 13.2[%] 높은 것으로 도출되었으며, DC 380[V]의 공급을 가정하였을 때에는 25[%] 이상의 효율 향상을 기대할 수 있었다.

백색 led 조명의 색온도에 관한 감성평가

Abstract: 이 연구의 목적은 백색 LED 조명의 광학적 특성 중에서 색온도 특성에 따른 사람들의 감성 반응을 평가하는데 있다. 이를 위해 백색 LED 모듈을 시제품으로 만들고, 감성 평가용 모형을 제작하여 색온도에 따른 감성 반응을 평가 분석하였다. 감성 평가에는 15개의 문항에 대하여 5단계 SD법으로 하였으며, 신뢰도 검증과 ...

웨이블릿 영상처리에 의한 도로표면상태 인식 및 분류

Abstract: 본 연구는 도로 관제 목적으로 사용 중인 가시 카메라(Visible Camera)를 사용하여 촬영한 도로표면 영상을 화상 인식 도로표면의 상태를 식별하는 방법과 기준을 제안하였다. 먼저, 입력 화상은 낮 시간대의 아스팔트 포장 도로면을 촬영하여 도로표면 상태의 화상을 만들었고, 편광 및 웨이블릿 변환(Wavelet transform)으로 도로 표면을 5가지의 상태(건조, 습윤, 수막, 적설, 동결)로 인식할 수 있는 분류기준절차를 연구하였다. 표면 화상 인식 과정은 편광계수(수직/수평 편광 비율) 값이 1.3 이상이면 젖은 땅으로 분류한 후, 다음으로 젖은 땅을 제외한 나머지는 웨이블릿 패킷 변환을 통해 시간-주파수 분석을 하였다. 또한 영상 템플릿을 이용하여 마른 땅과 빙판의 표준적인 주파수 특성을 분석하여, 마른 땅과 빙판을 구분하였다. 입력 영상에 대해서 제안한 도로표면상태의 인식분류 및 기준에 따라, 도로표면영상에서 마른 부분과 젖은 부분을 구분한 결과를 정리하였다.

Electrical Properties of ZnO:Al Transparent Conducting Thin Films for Film - Typed Dye Sensitized Solar Cell

Abstract: In this paper aluminium-doped zinc oxied(ZnO:Al) conduction layer was deposited on polytheylene terephthalate(PET) substrate by r. f. magnetron sputtering method. The effects of gas pressure and r. f. sputtering power on the structural and electrical properties of ZnO:Al thin film were investigated experimentally. Especially the effect of position of PET substrate on the electrical properties of the film was studied and fixed to improve the electrical properties and also to increase the deposition rate. The results show that the structural and electrical properties of ZnO:Al thin film were strongly influenced by the gas pressure and sputtering power. The minimum resistivity of 1.1×10 -3 [Ω-cm] was obtained at 5[mTorr] of gas pressure, and 180[W] of sputtering power. The deposition rate of ZnO:Al film at 5[mTorr] of gas pressure was 248[nm/min]. and is higher by around 3 times compared to that at 25[mTorr].

A Research of Optimum Supply Reserve Levels for Stability of Power System

Abstract: Because of the high increasing rate of load demand these days the necessity of deciding what optimum reserve level is appropriate to most stably supply electricity is being emphasized. This research studies the downward tendency of reserve ratio by analyzing the trend of change of the network scale, reserve, and reserve ratio while optimum reserve has been increased as the network system scale grow up. This means, at this moment 6,000[MW] is optimum level for short term prospect of power supply and demand. And also, it has been analyzed that, as the annual peak load exceeded 50,000[MW], confirming the amount of optimum reserve level is more stable than keeping 10 to 12[%] reserve ratio.

미세먼지의 집진효율 향상을 위한 전기집진기의 자계인가특성에 대한 연구

Abstract: 본 논문은 실내에 잔존하는 직징 1[μm] 이하의 미세먼지들을 집진하기 위하여 전기집진기를 설계하였으며, 이때 집진 효율의 극대화를 위하여 전계와 동시에 자계를 수직 및 수평으로 배치함에 따른 실험실 공기중에 포함된 미세먼지의 집진특성에 대하여 논하였다. 전계에 수평으로 자계를 인가한 경우는 자계의 유무 및 자석의 수량에 관계없이 집진효율이 거의 일정하게 나타났으며, 자석을 수평으로 배치하여 전계에 수직으로 인가한 경우는 비자화 페라이트 막대를 부착한 경우보다 약 5[%] 이상 집진효율이 향상되었다. 또한, 자계를 전계에 수직으로 인가하는 방법에 있어서, 자석을 접지전극의 가운데 정렬한 경우는 인가진압 5[kV]에서의 집진효율이 17~32[%]로서 자석을 앞쪽에 설치한 경우와 유사하였으며, 지그재그 및 안쪽 끝에 정혈시킨 정우는 집진효율이 17~38[%]로서 향상되었으며, 특히 0.7 및 1[μm]의 굵은 입자들에 대한 집진특성이 양호하였다. 따라서, 전기집진기의 집진특성을 향상시키기 위해서는 자계를 진계에 수직으로 접지전극의 중간 또는 지그재그 식으로 배치하는 것이 가장 적절한 것으로 판단된다.

A Position Sensorless Control System of SRM over Wide Speed Range

Abstract: This paper presents a position sensorless control system of SRM over wide speed range. Due to the doubly salient structure of the SRM, the phase inductance varies along with the rotor position. Most of the sensorless control techniques are based on the fact that the magnetic status of the SRM is a function of the angular rotor position. The rotor position estimation of the SRM is somewhat difficult because of its highly nonlinear magnetizing characteristics. In order to estimate more accurate rotor position over wide speed range, Neural Network is used for this highly nonlinear function approximation. Magnetizing data patterns of the prototype 1-hp SRM are obtained from locked rotor test, and used for the Neural Network training data set. Through measurement of the flux-linkage and phase currents, rotor position is able to estimate from current-flux-rotor position lookup table which is constructed from trained Neural Network. Experimental results for a 1-hp SRM over 16:1 speed range are presented for the verification of the proposed sensorless control algorithm.

Efficiency Optimization Control of IPMSM using Neural Network

Abstract: An efficiency optimization control system of an IPMSM(Interior Permanent Magnet Synchronous Motor) using a neural network are provided to optimize an operation efficiency by outputting an optimal reference current by using a core loss compensator, a parameter estimator, and the neural network. A speed measuring unit(8) obtains a speed which is inputted to a PI(Proportional-Integral) controller from an IPMSM(Interior Permanent Magnet Synchronous Motor). The PI controller(1) receives an error between a command speed and the speed of the IPMSM and outputs a q-axis command current. A neural network(2) receives the speed from the speed measuring unit, a parameter from a parameter estimator, and the q-axis command current, and outputs a d-axis command current. A core loss compensator(3) receives the q-axis and d-axis command currents and outputs a torque component command current and a magnetic flux component command current. The parameter estimator(5) receives the torque component command current, the magnetic flux component command current, the speed from the speed measuring unit, and the q-axis command current, and outputs a parameter variation ratio. A PWM(Pulse Width Modulation) inverter(4) receives the torque component command current, the magnetic flux component command current, and a rotor position, and outputs a 3-phase current and a 3-phase voltage.

A Study on low-Cost Sensorless Drive of Brushless DC Motor for Compressor Using Random PWM

Abstract: Recently, it is increased to apply sensorless drive for BLDC (Brushless DC) motor to household electrical appliances, especially in the refrigerators and air conditioners, to reduce the cost and the acoustic noise by the operation and to make their functions more comfortable for human beings. In this paper, low-cost sensorless drive for BLDE motor is implemented by random PWM (Pulse Width Modulation). The experimental results show that the electromagnetic noise was reduced and the sound quality was improved by BLDC motor sensorless random PWM Control.

A Characteristic Study on the Power Factor Correction Application for Induction Motor

Abstract: The field of induction motor is magnetized and demagnetized for each reversal of the current. This field component of the motor accounts for most of the reactive component of inductive load. Reactive power needs to sustain the electromagnetic field required for the induction motor to operate. Power factor of induction motor is usually low and power factor correction needs. Power factor becomes low by the effect of the reduction operation of load capacity. In most cases, Capacitor capacity for the power factor correction should be complied with the recommendation by the motor capacity. But Capacitor value for power factor correction can`t change during the normal operation. In this paper, we analyzed characteristics of power and power factor changing by load fluctuation of low-voltage small size induction motor and show that lower power factor correction`s parameter of existing recommendation should be revised by new value.

Transient Grounding Impedance Behaviors of Deeply-driven Ground Rods According to the Injection Point of Impulse Currents

Abstract: This paper presents the transient and conventional grounding impedance behaviors of deeply-driven ground rods associated with the injection point of impulse currents. The transient grounding impedance strongly depends on the length of deeply-driven ground rod and the rise time and injection point of impulse currents, and the intrinsic inductance of ground rod has a significant affect on the transient grounding impedance of grounding system in fast rise time ranges. The reduction of inductance is decisive to improve the impulse impedance behaviors of deeply-driven ground rods. It is effective that grounding conductor is connected to the top of the ground rod as short as possible.

Research on Assessment of Potential Interference between Individual Grounding Electrodes Using an Electrolytic Tank Modeling Method

Abstract: This paper deals with the assessment of potential interference between individual grounding electrodes using an Electrolytic Tank Modeling method, When a test current was passed through a grounding electrode, potential rise was treasured and analyzed using an electrolytic tank in real time. In order to analyze the potential interference between grounding electrodes, a reduced scale modeling method was studied. Potential interference between isolated grounding electrodes was evaluated as a function of the separation distance between grounding electrodes and the configuration of grounding electrode to be induced. It was found that the separation distance between grounding electrodes was a major factor in reducing the potential interference.

The Recognition and Segmentation of the Road Surface State using Wavelet Image Processing

Abstract: This study focus on segmentation process that classifies road surfaces into 5 different categories, dry, wet water, icy, and snowy surfaces by analyzing asphalt-paved road images taken in daylight. By using the polarization coefficients, the proportions of horizontally polarized components to vertically polarized components, regions with over 1.3 polarization coefficients are classified as wet surfaces. Except for wet surfaces, the decision process a lies time-frequency analysis to other parts by using the third order wavelet packet transform. In addition, by using the average frequency characteristics of dry and icy surfaces from image templates, decide which is closer to a test image, and finally identify dry and icy surfaces. It is confirmed that the reposed estimation and segmentation of recognition on various images. This can be interpreted as an indication that image-only mad surface condition supervision is probable.

Analysis of Soil lonization Characteristics in Concentric Cylindrical Electrode System under Impulse Voltages

Abstract: This paper presents the soil ionization phenomena and the parameters with the transient characteristics of model grounding system under lightning impulse voltages. lonization properties of dry and wet sands were investigated by using two test cells of concentric cylindrical electrode system with different dimensions. As a result non-linear electrical behavior of sand under high impulse voltage is caused by ionization process. The transient impedance of sand depends not only on the water content but also on the magnitude of applied impulse voltages. The grounding impedance is decreased with increasing the water content and the magnitude of a lied voltages. The results resented in this paper will provide useful information on the design of high performance grounding systems against lightning surge.

Suitability Review for Power Correction Parameter of Induction Motor

Abstract: Induction motor needs reactive power to sustain the electromagnetic field required for rotating. If reactive power is provided by the load side instead of the source side, power factor will be increased. Power factor of induction motor is usually low and needs to be compensated with power capacitor. In domestic regulations, Capacitor capacity for the power factor correction of induction motor should be complied with the recommended value by the motor output. But, at the same output, characteristics of induction motor is different from each other by the rotation speed and is not suitable for application of regular capacitor value regardless of motor`s characteristics. In this paper, we compared to each other with the existing value and new proposed value with rotation speed under the same output condition, confirmed that power capacitor capacity is needed to upgrade for the better power factor.

A Study on the Frequency Control on the Induction Heating System Using Two Step Resonant Inverter

Abstract: Proposed induction-heated system is innovative system which applied special high-frequency power circuit technique for thermal converse technique and IH(Induction-Heating) magnetic induction heating generated from induction-heated metallic package that is for distillation unit. In this occurs not burning, so that the working environment can be improved. This electromagnetic induction heating technique is used high frequency inverter. By using high frequency inverter high frequency alternative current (HFAC) in the range of [kHz] can be made with conventional alternative current. In this contribution IGBT module is used for high frequency inverter. In this paper are discussed action analysis and characteristics analysis of 1.5[kW]-Class half-bridge resonant inverter system and resonant metallic package. In addition, by using this system, how two step heating superheated steam generator is developed and application of system are also discussed.

A Study on the Reverse-Power-Flow Phenomenon due to Transformer Wiring Types in Distribution System

Abstract: As the penetration of distributed generation systems is recently high, there have been metering errors, trips of protective devices in KEPCO distribution systems including an occurrence of false fault-indicator in distribution automation system. The cause of malfunctions was the reverse-power-flow phenomenon due to transformer wiring types. By the effect of the reverse-power-flow, each of phase`s fundamental currents was added by about 3 times on the neutral line. A new method based on the analysis of the reverse-power-flow is proposed in this paper. Fault currents on each section were analyzed by the proposed method, and the effect of types of transformer wiring was examined experimentally. In order to reduce the malfunctions due to the reverse-power-flow, controlling the zero-sequence impedance of transformer was designed and verified by using PSCAD/EMTDC software.

Influence of Combustion Flame on Breakdown Characteristics of Vertical-Model Power Lines

Abstract: Occurring forest fire or burning bushes beneath overhead transmission lines have caused breakdown disturbances of the system in many countries. In this study, experiments for flashover characteristics in the simulated condition of vertical power lines were conducted so as to investigate the reduction in insulation strength caused by combustion flame. As the results of an experimental investigation, it is demonstrated that flame can reduce breakdown voltages of the model lines according to height(h) of flame. The breakdown voltages were decreased with decreasing the height(h) of flame it can be seen that the average reduction of flashover levels, in comparison with the no-flame case, are 46.2[%] for h

Ups용 납축전지를 위한 배터리관리시스템

Abstract: 본 논문에서는 무정전 전원시스템(UPS : Uninterruptible Power Supply)의 에너지 저장용으로 사용되는 납축전지를 최적의 상태로 유지, 관리하는 배터리관리시스템을 설계, 제작하고, 잔존용량을 추정하는 알고리즘을 제안한다. 제안된 배터리관리시스템은 배터리의 충ㆍ방전 전류를 제어하여 과방전 및 과충전으로부터 배터리를 보호하며, 충ㆍ방전 시 배터리 잔존용량(SOC)을 예측하여 배터리를 최적 상태로 유지하도록 하는 알고리즘이 적용된다. 또한 충ㆍ방전 시험기를 이용한 실험과 UPS에 장착한 후 성능 실험을 통해, 제작된 시스템의 성능 및 제안된 배터리 잔존용량 추정 알고리즘의 타당성을 입증한다.

Implementation of o Novel WDMX Controller for LED Lights

Abstract: This paper describes the proposal, design, and implementation of a novel WDMX controller which can provide versatile light effects with the increased capability of the mobility and the number of universes for LED lights. Both the algorithm for DMX protocol and how to implement the frame based on a 8bit micro-controller are explained. The conversion algorithm between the DMX frame and wireless LAN 802. 11b protocol stack is introduced and implemented. In final, some experiments are made to verily the interoperability of the developed WDMX controller with a commercial product of LED lights. 최대 9,999 staves with 30 refresh rate per second may have capability to show various light effects.