• Title/Summary/Keyword: Minimum power line

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Optimal Transmission Expansion Planning Considering the Uncertainties of Power Market (전력시장 불확실성을 고려한 최적 송전시스템 확장계획)

  • Son, Min-Kyun;Kim, Jin-O
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.4
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    • pp.560-566
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    • 2008
  • Today, as the power trades between generation companies and power customer are liberalized, the uncertainty level of operated power system is rapidly increased. Therefore, transmission operators as decision makers for transmission expansion are required to establish a deliberate investment plan for effective operations of transmission facilities considering forecasted conditions of power system. This paper proposes the methodology for the optimal solution of transmission expansion in deregulated power system. The paper obtains the expected value of transmission congestion cost for various scenarios by using occurrence probability. In addition, the paper assumes that increasing rates of loads are the probability distribution and indicates the location of expanded transmission line, the time for transmission expansion with the minimum cost for the future by performing the Montecarlo simulation. To minimize the investment risk as the variance of the congestion cost, Mean-Variance Markowitz portfolio theory is applied to the optimization model by the penalty factor of the variance. By the case study, the optimal solution for transmission expansion plan considering the feature of market participants is obtained.

Fault Location and Classification of Combined Transmission System: Economical and Accurate Statistic Programming Framework

  • Tavalaei, Jalal;Habibuddin, Mohd Hafiz;Khairuddin, Azhar;Mohd Zin, Abdullah Asuhaimi
    • Journal of Electrical Engineering and Technology
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    • v.12 no.6
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    • pp.2106-2117
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    • 2017
  • An effective statistical feature extraction approach of data sampling of fault in the combined transmission system is presented in this paper. The proposed algorithm leads to high accuracy at minimum cost to predict fault location and fault type classification. This algorithm requires impedance measurement data from one end of the transmission line. Modal decomposition is used to extract positive sequence impedance. Then, the fault signal is decomposed by using discrete wavelet transform. Statistical sampling is used to extract appropriate fault features as benchmark of decomposed signal to train classifier. Support Vector Machine (SVM) is used to illustrate the performance of statistical sampling performance. The overall time of sampling is not exceeding 1 1/4 cycles, taking into account the interval time. The proposed method takes two steps of sampling. The first step takes 3/4 cycle of during-fault and the second step takes 1/4 cycle of post fault impedance. The interval time between the two steps is assumed to be 1/4 cycle. Extensive studies using MATLAB software show accurate fault location estimation and fault type classification of the proposed method. The classifier result is presented and compared with well-established travelling wave methods and the performance of the algorithms are analyzed and discussed.

Novel Criterions to determine Optimized Power coupling in Grating-Assisted Fiber Couplers (GAFCs) (격자구조형 광섬유 결합기에서 최적 전력결합을 결정하기 위한 새로운 조건)

  • Ho, Kwang-Chun;Ho, Kwang-Soo
    • Korean Journal of Optics and Photonics
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    • v.17 no.2
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    • pp.120-126
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    • 2006
  • A grating-assisted fiber coupler(GAFC), which consists of a thin-film waveguide with grating and circular optical fiber, is proposed and the optimized power coupling is evaluated by using a technique amenable to rigorous longitudinal modal transmission-line theory(L-MTLT). In addition, novel criteria to couple an optical signal incident through the grating waveguide to a single-mode optical fiber are proposed. The numerical result reveals that the optimized power coupling occurs at minimum-gap condition between rigorous modes rather than for the conventional phase-matching condition.

A Study on the Design of Linear Power Amplifier at Digital Control System (디지털 제어방식의 선형전력증폭기 설계에 관한 연구)

  • 김갑기;조학현;조기량
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.5
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    • pp.724-730
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    • 2002
  • Digital communication systems are required to cause the minimum interference to adjacent channels, they must therefore employ the linear power amplifiers. In respect to linear power amplifiers, there are many linearization techniques. Feedforward power amplifier represent very wide bandwidth and high linearization capability. In the feedforward systems, overall efficiency is reduced due to the loss of delay line. In this paper, delay filter instead of transmission delay line adapted to get more high efficiency. Experimental results showed that ACLR (Adjacent Channel Leakage Ratio) has improved 17.43(dB), which is added 3.44(dB) by using the delay filter.

Design Equations for the H-plane Power Divider with a Circular Post in a Rectangular Waveguide

  • Han Sang-Sin;Lee Sun-Young;Ko Han-Woong;Park Dong-Hee;Ahn Bierng-Chearl
    • Journal of electromagnetic engineering and science
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    • v.4 no.4
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    • pp.150-155
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    • 2004
  • Universal design equations are presented for the H-plane T-junction power divider with a circular conducting post in a rectangular waveguide. For a given operating frequency and power split ratio, the post offset from the T-junction center line, the distance between the post and the waveguide wall, and the post diameter can be adjusted to obtain a minimum reflection at the input waveguide. Optimum values of the post offset are given in terms of the normalized frequency and the power split ratio. Corresponding values of the post diameter and the distance of the post from the waveguide wall are given in terms of the normalized frequency and the post offset.

Dimming Control Signal Transmisson of Electronic Ballast on the Power Line and Characteristics Measurement (전력선을 이용한 전자식 안정기 조광 신호 전송과 특성 측정)

  • 이상곤;정은택;강복연;양병렬;유홍균
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.4
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    • pp.691-700
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    • 1994
  • A power line in not so good in characteristics for communication, because it is a media to transfer the commercial electrical power, and its load noise and high frequency noise are so much. Thus, a simple method to transfer a remote control signal on the power line is studied. The already-existing method is that two signals with upper part eliminated is transmitted every N step. But the method is investigated which the transmitter sends a period signal eliminated in arbitrary phase. Thus the transmission power loss due to elimination of signal can be reduced to the minimum. To implement it, a timer calculating the time from zero-crossing point to the phase is required. The micro-controller, 87C51, precisely calculates the phase using one of two built-in timers. As a result, a remote control signal tramsmitter and receiver using a partially eliminated signal, which is better than the conventional technique using half-eliminated signal in a efficiency of power transmission, is realized, and its characteristics are analyzed.

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Design and Analysis of a Memoryless Minimum Bandwidth Birnary Line Code MB58 (Memoryless 최소대역폭 2진 선로부호 MB58의 설계 및 분석)

  • 김정환;김대영
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.10
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    • pp.1074-1080
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    • 1992
  • A(5,8) block binary line code is proposed. The new line code called MB58 has the properties of being dc-free and runlength-limited, and it is strictly bandwidth-limited to the Nyquist frequency, such that bandwidth efficiency is improved. This new code is a memoryless code with a simple decoding rule and capability of error monitoring. The power spectrum and the eye pattern of the new code are obtained by simulation, wherein spectral nulls at DC(f=0) and Nyquist frequency (f=1/2Ts) are clearly identified.

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Fabrication of Al-doped ZnO Thin Films by Vertical In-line DC Magnetron Sputtering

  • Heo, Gi-Seok;Kim, Tae-Won;Lee, Jong-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.04c
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    • pp.41-41
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    • 2008
  • Al-doped ZnO (AZO) thin films have been fabricated by vertical in-line dc magnetron sputtering for transparent conducting oxides (TCOs) applications. The effects of substrate temperature and dc power on the characteristics of AZO thin films are investigated and also optimized the process conditions to get the best electrical and optical properties. The fabricated thin films show a good electrical and optical uniformity within ${\pm}5%$ over the whole area of substrate ($200mm\;{\times}\;200mm$) ; the minimum resistivity of $8\;{\times}\;10^{-4}\;{\Omega}cm$ and the average transmittance of 90% within the visible wavelength range. We have found that the band gap ($E_g$) increases with increasing substrate temperature and dc power, whereas the crystallinity is getting improved with increasing substrate temperature. The binding energy of Zn $2p_{3/2}$ and O 1s is observed to decrease as the substrate temperature increases.

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Magnetic Field Analysis in Accordance with Line Configuration Type in Underground Transmission Systems (지중송전계통에서 선로의 구성방식에 따른 자계 해석)

  • Lee, Jae-Myeong;Lee, Jong-Beom
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.12
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    • pp.1673-1678
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    • 2015
  • This paper describes magnetic field on power cable in underground transmission systems. Based on specification which is being used in domestic power utility, magnetic field was analyzed in accordance with line arrangement, line burial depth and phase spacing. Magnetic field magnitude and its trend were understood in each circuit type such as double circuits, triple circuits and quadruple circuits of underground transmission systems. In addition, magnetic field was analyzed according to phase arrangement changing in each circuit. Finally, the proper phase arrangement configuration type was suggested by the evaluation of analysis result. Magnetic field was calculated by using Biot-Savart's law. According to the evaluated magnetic fields based on phase layout configuration in each circuit, it figured out that each of magnetic fields was different. As a result, this paper proposes a proper phase layout configuration for generating minimum magnetic field. It is evaluated that the phase layout configuration in each circuit proposed in this paper can be used at actual underground transmission systems.

Maintenance Staff Scheduling at Afam Power Station

  • Alfares, H.K.;Lilly, M.T.;Emovon, I.
    • Industrial Engineering and Management Systems
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    • v.6 no.1
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    • pp.22-27
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    • 2007
  • This paper describes the optimization of maintenance workforce scheduling at Afam power station in Nigeria. The objective is to determine the optimum schedule to satisfy growing maintenance labour requirements with minimum cost and highest efficiency. Three alternative maintenance workforce schedules are compared. The first alternative is to continue with the traditional five-day workweek schedule currently being practiced by Afam power station maintenance line. The second alternative is to switch to a seven-day workweek schedule for the morning shift only. The third alternative is to use a seven-day workweek schedule for all three work shifts. The third alternative is chosen, as it is expected to save 11% of the maintenance labour cost.