• Title/Summary/Keyword: Load share

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The Study on the Actual Examination of the Bidirectional Protection Device in the 22.9[kV] Distribution Power System Interconnected with the DG (분산전원이 연결된 22.9[kV] 배전계통의 양방향 보호기기 실증시험 연구)

  • Lee, Heung-Jae;Choi, Myeong-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.10
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    • pp.102-108
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    • 2011
  • The existing power flow has a single direction to the line end but the bidirectional power flow will possibly occur depending on the output capacity in the 22.9[kV] distribution power system connected with the dispersed generation(DG). So these characteristics would influence the power system management. The DG have many advantages such as assistance source, Load share etc. So the utility must apply the bidirectional protection system so as to maximize an advantage of DG. This paper describes the field test case of bidirectional protective device in order to investigate the device performance when applied to bidirectional power system. We have tested in the power system test site of KEPCO and these tests provide the basis for performance verification test of bidirectional protective device in the power system.

Evaluation of Packet Loss Rate in Optical Burst Switching equipped with Optic Delay Lines Buffer

  • To, Hoang-Linh;Bui, Dang-Quang;Hwang, Won-Joo
    • Proceedings of the Korea Multimedia Society Conference
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    • 2012.05a
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    • pp.166-167
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    • 2012
  • High packet loss rate and impatience of messages passing through optical switches are essential characteristics in Optical Burst Switching system equipped with Optic Delay Lines buffer, which have not been solved efficiently yet by current existing models. In order to capture both effects, this paper introduces an analytical model from the viewpoint of classical queuing theory with impatient customers. We then apply it to evaluate and compare two wavelength-sharing cases, (1) all delay lines share a common wavelength resource and (2) each wavelength is associated with a number of delay lines. Our numerical results suggest to implement the first case because of lower packet loss rate for a fairly broad range of traffic load.

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The Parallel Operation of ZVT-Full Bridge Converter with Dynamic Current Shared Inductor (동적 전류분담 인덕터를 적용한 ZVT 풀 브리지 컨버터의 병렬 운전)

  • Bae, Jin-Yong;Kim, Yong;Baek, Soo-Hyun;Kwon, Soon-Do;Lee, Kyu-Hoon;Kim, Cherl-Jin
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.942-945
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    • 2001
  • This paper presents parallel operation of ZVT(Zero Voltage Transition) Full Bridge Converter with Dynamic Current Shared Inductor. In the conventional method, CT(Current Transformer) have been used to share the load current equally with converters. In this system, at parallel operation of ZVT Full Bridge Converter, dynamic current shared inductor divides the same current of unit converter and ZVT circuit aids to high efficiency. This method which is proposed to compare in the conventional method will do simple control circuit. To show the superiority of this converter is verified through the experiment with a 2kW, 50kHz prototype converter.

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Analysis on the Promotion Programs for High-Efficiency Induction Motors (고효율전동기 보급정책의 경제성 분석)

  • 김발호;정구형;전영환
    • Journal of Energy Engineering
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    • v.12 no.2
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    • pp.118-123
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    • 2003
  • Motor-driven systems are the largest electrical load and share about 40% of electric energy consumption in Korea. Increasing the efficiency of drive-power systems, therefore, is one of the most urgent demand side programs to be designed and launched. This paper presents an extensive analysis on the alternative rebate programs viable to enhancing the adoption of high-efficiency induction motors, and suggests government activities supporting market transformation initiatives.

A Study for Rationalization of Lifting Lug Design of Ship Block (선박블록 탑재용 러그구조의 설계합리화를 위한 연구)

  • 함주혁
    • Journal of Ocean Engineering and Technology
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    • v.11 no.4
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    • pp.249-261
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    • 1997
  • A basic study on the lifting lug design has performed through the rational and systematic process. In order to evaluate the proper design-load distribution around lug eye investigation of contact force between lifting lug and shackle pin is performed using non-linear parametric analysis idealized by gap element models. Gap element modeling and nonlinear analysis procedures are illustrated and discussed based on MSC/NASTRAN. Some analysis and design guides are suggested through the consideration of several important effects such as stress distribution pattern, circumferential contact force distribution along the lug eye face, loading share rate between lug main plate and doubler, effect of loading direction, relation between applied force and deflection and size effect of shackle pin radius. Additionally optimum design studies are performed and general trends according to the variation of design parameters are suggested.

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The Parallel Operation of ZVT-Full Bridge Converter with Dynamic Current Shared Inductor (동적 전류분담 인덕터를 이용한 ZVT 풀 브리지 컨버터의 병렬 운전)

  • Kim, Yong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.4
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    • pp.15-21
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    • 2002
  • This paper presents parallel operation of ZVT(Zero Voltage Transition) FUll Bridge Converter with Dynamic Current Shared Inductor. In the conventional method, CT(Current Transformer) have been used tn share the load current equally with converters. In this system, at parallel operation of ZVT Full Bridge Converter, dynamic current shared inductor divides the same current of unit converter and ZVT circuit aids to high efficiency. Superiority of the characteristics is verified through the experiment with a 2[㎾], 50[㎑] prototype converter.

A Study Of Parallel Characteristics Of 50[W] Virtual Implement of 50[W]Solar Cell modules Using Droop-Method (Droop Method를 이용한 50[W]급 태양전지 가상구현 시스템의 병렬연결 출력특성에 대한 연구)

  • Lee B.I.;Lee S.Y.;Oh B.W.;Jung B.H.;Choe G.H.
    • Proceedings of the KIPE Conference
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    • 2003.07b
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    • pp.692-695
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    • 2003
  • Generally, photovoltaic system is composed with several solar cell modules. For increasing power of photovoltaic systems, serial and parallel connection needed. A Desirable characteristic of a parallel supply system is that individual converters share the load current equally and stably. The current sharing(CS) can be implemented using two approaches. The first one, known as a droop method, relies on the high output impedance of each converter. and The second approach, known as active current-sharing techniques. In this paper, using droop method at parallel connection with it's convenience and simplicity.

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Parallel operation of VISC system for 3[kw] solar cell (3[kw]급 태양전지 가상구현시스템의 병렬운전)

  • Lee S.Y.;Jeong B.H.;Oh B.W.;Lee B.I.;Choe G.H.
    • Proceedings of the KIPE Conference
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    • 2003.07b
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    • pp.957-960
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    • 2003
  • Many solar cell way need to be connected by series or parallel to extract the high power Especially, during parallel operation to reduce circulation current the individual converter has to share and control the load current. Generally, Current Sharing(CS) can be implemented using droop and active current sharing method. In this paper, one 3[KW] PWM converter was replaced as one 3[KW] solar cell array(3 parallels, each parallel has twenty single modules), two 3[KW] solar cell way Is Paralleled to generate 6[KW] power. Also each converter used voltage-current controller and Automatic MSCPM(Master-Slave Current-programming Method) for current sharing(AS).

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A study of Multiple parallel Characteristics of 50[W] Virtual Implement of 50[W] Solar Cell modules Using Droop-Method (Droop Method를 이용한 50[W]급 태양전지 가상구현장치의 다중병렬연결 출력특성에 관한 연구)

  • Lee Byung-In;Lee Sang-Yong;Jung Byung-Hwan;Choe Gyu-Ha
    • Proceedings of the KIPE Conference
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    • 2003.11a
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    • pp.81-84
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    • 2003
  • For increasing power of photovoltaic systems, serial and parallel connection needed. In parallel connection, a desirable characteristic of parallel-connected supply system is that individual converters share the load current equally and stably. The current sharing(CS) can be implemented using two approaches. The first one, known as a Droop method, and the other is Active current-sharing. In Droop method, current distribution characteristics relies on the high output impedance of each converter. This scheme is more simple and no need interconnections. but also has a disadvantages of degrading current sharing characteristics. In this paper, using droop method at multiful-parallel connection with it's convenience and simplicity.

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Novel Approach to Analytical Jitter Modeling

  • Huremovic, Adnan;Hadzialic, Mesud
    • Journal of Communications and Networks
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    • v.17 no.5
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    • pp.534-540
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    • 2015
  • In this paper we propose an analytical model for jitter, wherein we implement the interrupted Poisson process (IPP) for incoming traffic. First, we obtain an analytical model for the jitter on one node with respect to the phase probabilities, traffic load, and tagged traffic share in the aggregate traffic flow. Then, we analyze N-node cases, and propose a model for end-to-end jitter. Our analysis leads to some fast-to-compute approximations that can be used for future network design or admission control. Finally, we validate our analytical results by comparing them with previous results for limit cases, as well as with event-driven simulations. We propose the use of our results as guidelines for jitter evaluation of real IP traffic.