• 제목/요약/키워드: Switching Surge

검색결과 159건 처리시간 0.029초

345kV 혼합송전선로에서 재폐로가 절연설계에 미치는 영향 (Effects of Reclosing for Insulation Coordination in 345kV Combined Transmission Lines)

  • 이종범;정채균;임광식;강지원
    • 전기학회논문지
    • /
    • 제59권5호
    • /
    • pp.847-853
    • /
    • 2010
  • This paper describes switching surge analysis for reclosing decision in 345kV combined transmission line with XLPE power cable. Reclosing operation should be decided based on the detailed technical analysis in combined transmission line because this line includes power cable section which is week on insulation. Insulation of power cable can be breakdown at the week point in case of reclosing moment. Therefore the detailed analysis has to be carried out by considering several conditions such as length ratio of power cable section, arrestor, inserting resistance, charging rate, grounding resistance, etc.. On the other hand sheath voltage on IJ(Insulated Joint) is analyzed to check dangerous condition on cable cover. Analysis is performed by EMTP/ATP. Analysis results show that reclosing can be operated as the single line-to-ground fault occurs on overhead line in 345kV combined transmission line, if the inserting resistance is considered before the operation of main circuit breaker.

한국 생수산업의 해외시장진출 전략에 관한 연구 (A Study on the Foreign Entry Strategy of Korean Mineral Water Industry)

  • 홍성헌
    • 통상정보연구
    • /
    • 제12권4호
    • /
    • pp.363-382
    • /
    • 2010
  • It should be unthinkable to not provide water at survival of any living things. Water is too a basic element for development for a country. Currently, the global market of mineral water is growing rapidly. This study, I conceptualized mineral water as bottled water. In particularly, bottled water has seen huge global growth for the last few years. The annual growth rate of the market in the period 2005-2009 was 5.9%. Following a surge in obesity and subsequent health and wellness trends, many consumers are switching from sugary soft drinks to healthier alternatives. Therefore, the global bottled water market is one area which has big potential for growth, but price competition is getting intensified among multi-national and domestic firms. Korean providers too are faced with strong competition in growing domestic market. The bottled water market has presence of multinational provider like Nestle, Danone and Coca-Cola, which collectively account for 35.1% of the world market share in 2009. On the basis of a market orientation approach, this article looks at changing environments in the world mineral water industry and attempts to describe foreign market entry strategy of the Korean mineral water industry. The market orientation provides strong norms for learning from customers and competitors, is instrumental in creating a superior value for buyers, innovating successfully, and generating excellent firm performance. So firms should consider a strategic planning in basis on market orientation before they enter foreign markets. Some discussions were made about managerial implications for Korean bottled water providers.

  • PDF

정보통신기기용 과도이상전압 고속도차단장치의 설계 및 제작 (Design and Fabrication of a High Speed Blocking Device of Transient Overvoltages for info-communication Facilities)

  • 길경석
    • 대한전기학회논문지:전기물성ㆍ응용부문C
    • /
    • 제48권1호
    • /
    • pp.51-56
    • /
    • 1999
  • This paper presents a new transient overvoltage blocking device (TOBD) for info-communication facilities with low power and high frequency bandwidth. Conventional protection devices have some problems such as low frequency bandwidth, low energy capacity and high remnant voltage. In order to improve these limitations, thehybrid type TOBD, which consists of a gas tube, avalanche diodes and junction typefield effect transistors (JFETs), was designed and fabricated. The TOBD differs from the conventional protection devices in configuration, and JFETs were used as an active non-linear element and a high speed switching diode with low capacitance limits high current. Therefore the avalanche dilde with low energy capacity are protected fromthe high current, and the TOBD has a very small input capacitance. From the performance test using combination surge generator, which can produce $1.2/50\mus\;4.2kV_{max}\; 8/20\mus\; 2.1kA_{max}$, it is confirmed that proposed TOBD has an excellent protection performance in tight clamping voltage and limiting current characteristics.

  • PDF

전류공진을 이용한 고주파 유도가열용 전원장치 (The Power Supply for High Frequency Induction Heating by using the Current Resonance)

  • 라병훈;이은영;송대현;서기영;이현우
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
    • /
    • pp.263-266
    • /
    • 2002
  • In this paper, It is indicating that an issues of the conventional boost converter for high frequency induction heating. To improve those issues, it is proposed, simulated and analyzed that the current resonant circuit, simulated. As the result, we knew that the proposed circuit has a good point to improve the waveform of input current and to make high efficiency. On the other side, in the inverter for the high current power supply, it is proposed that the high frequency inverter of the half bridge topology, be done the circuit analysis to extract the optimal circuit parameter. It is making sure of the soft switching operating by the inductor to reverse parallel connected on the inverter main switch, decreasing the surge voltage when the switch is turn-off by compulsion, and repressing the switch current and bringing the high current amplitude operation by the multi resonance.

  • PDF

새로운 유지구동전압 반감형 AC PDP 구동회로 (A New Sustaining Driver for AC PDPs with Reduced Sustain Voltage by Half)

  • 임승범;조필용;채수용;강경우;유종걸;고종선;홍순찬
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2005년도 전력전자학술대회 논문집
    • /
    • pp.452-455
    • /
    • 2005
  • This paper proposes a new sustaining driver for AC PDP(Plasma Display Panel), which improves the performance of conventional circuit with reduced sustain voltage such as TERES(TEchnology of REciprocal Sustainer). In the TERES circuit, the sustain voltage is the half of general sustaining driver and there is no energy recovery circuit. The circuit proposed in his paper has an energy recovery circuit and removes surge currents. Although the energy recovery circuit is added, the number of active switching elements is the same as the TERES circuit. The operations of the proposed circuit are analyzed for each mode and its validity is verified by the simulations using PSpice program.

  • PDF

PSCADI/EMTDC를 이용한 시송전계통의 고조파 공진현상 분석 II (Analysis of the Harmonic Resonance of Primary Restorative Transmission System Using PSCAD/EMTDC PART II)

  • 이흥재;유원근;이경섭;박성민
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2004년도 하계학술대회 논문집 A
    • /
    • pp.48-50
    • /
    • 2004
  • The energization of high voltage transmission lines and transformers, that is an inevitable process in most countries as the first restorative action for wide-area blackout, may induce overvoltages such as sustained overvoltage, transient overvoltage and harmonic resonant overvoltage. And these may cause damages to power system equipments or failure of surge arresters. The harmonic resonant overvoltage originates in switching operations and nonlinear characteristics of equipments. Actually it is difficult to predict the occurrence of harmonic overvoltage, since they result from nonlinear characteristics of transformers and other equipments. This paper describes the analysis of domestic primary restorative transmission system using PSCAD/EMTDC. The harmonic resonance is verified and the solution to prevent harmonic resonance is proposed in this paper. As a result, the PSCAD/EMTBC simulation showed slightly conflictive results that had been presented by IEEE Power System Restoration Working Group report.

  • PDF

데이터센터 자원 연결 방안 연구 (A Study on Connections of Resources in Data Centers)

  • 기장근;권기영
    • 한국소프트웨어감정평가학회 논문지
    • /
    • 제15권2호
    • /
    • pp.67-72
    • /
    • 2019
  • 최근 인터넷 보급과 함께 폭발적으로 증가하고 있는 클라우드 서비스 등의 데이터 트래픽 급증으로 데이터 센터의 구성 자원들을 효율적으로 연결할 수 있는 초고속 광모듈 네트워크의 필요성이 급증하고 있다. 본 논문에서는 광스위치 연결구조에서 스위칭 셀 동작을 제어하기 위한 알고리즘들을 제안하고, 이에 따른 성능을 시뮬레이션을 통해 비교 분석하였다. 성능 분석결과 본 논문에서 제안하는 알고리즘이 기존 알고리즘에 비해 1:2 이상의 다중연결설정 성공확률이 약 3~7% 정도 향상됨을 보였다.

직렬아크현상의 검출기술 및 장치 (Detection Technique and Device of Series Arcing Phenomena)

  • 지홍근;정광석;박대원;길경석;서동환;류길수
    • Journal of Advanced Marine Engineering and Technology
    • /
    • 제34권2호
    • /
    • pp.332-338
    • /
    • 2010
  • 전력계통에서 아크현상이 원인이 되는 전기화재는 전기제품의 사용증가에 따라 급증하고 있으나, 이들 사고를 방지할 수 있는 확립된 방법은 없다. 이들 배경에서 본 논문은 공기조화기에서 직렬아크 검출 기술과 장치에 대한 실험적 결과에 대해 기술하였다. 공기조화기의 불완전한 접속부에서 발생하는 직렬아크를 모의하고, 주파수 스펙트럼을 FFT로 분석한 결과, 190 kHz~250 kHz와 900 kHz~1.6 MHz 에 존재함을 알 수 있었다. 저역차단주파수가 170 kHz이며 60 Hz를 176 dB까지 감쇄시킬 수 있는 아크검출 및 파형정형 회로를 설계하였다. 또한 스위치 조작, 인버터 운전 및 서지 등에 의해 발생하는 노이즈로부터 직렬아크신호를 분리할 수 있는 알고리즘을 제안하였다. 적용실험은 UL1699에 규정 되어있는 아크발생장치를 이용하여 여러 형태의 공기조화기에서 수행되었으며, 99 %이상 검출능력을 나타내었다.

고속전차선로 유리애자 현장 적합성 기반 구축 연구 (The Suitability of Toughened Glass Stem Insulator for Korea High Speed Catenary System)

  • 이기천;전용주;이종우
    • 한국철도학회논문집
    • /
    • 제12권2호
    • /
    • pp.243-248
    • /
    • 2009
  • 고속철도의 전차선로에 사용되는 유리애자는 국내에 적용 사례가 없으며 해외에서도 프랑스를 중심으로 한 정적으로 적용되는 품목으로서 국내 적용시 특성분석을 통한 적합성 평가가 요구된다. 본 논문에서는 2004년 이후 운영데이터를 바탕으로 유리애자의 현장 적합성을 평가하기 위해 전기적, 기계적, 외부적(환경) 요인의 3가지 대항목을 선정하여 분야별로 특성 분석을 수행하여 기초데이터를 축적하고 적합성을 평가하였다.