• Title/Summary/Keyword: Electric Power Lines

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Electromagnetic Induction Voltage according to the Position of Telecommunication Line from the Power Feeding Plant of Electrified Railway System (전기철도의 급전소 위치 관계에 따른 통신선 전자유도 전압)

  • Lee, Sangmu;Choi, Munhwan;Cho, Pyung-Dong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.05a
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    • pp.689-692
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    • 2015
  • That induced voltage by an electrified railway line is related with the position of telecommunication line between traction power feeding systems is practically varified by measurements in the real field. This experimented fact is conformed with the calculated simulation provided by the ITU-T Directives concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines. Therefore it is needed to consider at what position a telecommunication line is parallelized with power feeding line of traction system when an induction phenomenon is evaluated or measurement is carried out besides the length of parallelization and the separate distance between power line and telecommunication line.

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The Design and Implementation of AMI System Using Binary CDMA (Binary CDMA 기반의 AMI 시스템 설계 및 구현)

  • Joe, In-Whee;Jeong, Jong-Yuel
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.8C
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    • pp.663-669
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    • 2012
  • To solve the energy problem and finding new growth engines, interest for the smart grid is increasing and related technologies are making great efforts to secure in the world. AMI (Advanced Metering Infrastructure) Among them is the first to be constructed and getting attention as a key component of smart grid. A fusion of various technologies in technology development and demonstration is underway on Jeju Island Smart Grid Demonstration Complex in Korea, and focusing on broadband power line communication technology infrastructure is actively underway in Korea Electric Power Corporation. AMI system using power line communication technology without building a separate communication lines are available for power supply lines, but communication is impossible in occurs because admission to the power company or the ideal infrastructure for communication is not considered. In this paper, we analyze the requirements to build AMI system using Binary CDMA and powerline communications technology, and design the basic communication protocol based on Binary CDMA, implement network management and relay feature. By doing so, ways to apply Ad-hoc Binary CDMA indigenous technology to the AMI system were derived, and could build a system to make use of Wired (PLC) and wireless (Binary CDMA) simultaneously.

Point Beach Nuclear Plant Application Study For Power System Stabilizers (Point Beach 동자력발전기에 전력계통안정장치에 대한 연구)

  • Ju-Jang Lee
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.32 no.9
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    • pp.315-324
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    • 1983
  • Dynamic stability problems have been experienced with a generator connected to an infinite bus through a long transmission line. Nuclear turbine-generator units #1 and #2 at the Winsconsin Electric Power Point Baech Station were found to be dynamically unstable when one unit is isolated on one of the lines to Milwaukee or when two units are isolaed on the lines to milwaukee. Power System Stabilizers(PSS) were applied to the excitation system to provide stable operation under these conditions. Suitable settings for the PSS were predetetermined analytically by computer method and root licus analysis of an equivalent single machine-infinite bus configuration. This procedure allows graphical approach to the design of power stabilizers and serves as assynthesis procedure when the design constraints are relaxed so the the speed stabilizer is required ro provide animprovement in system damping. A simplified model of the complete exciter generator system is shown to be adequate for this type of analysis.

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Development of a Monitoring Equipment of Current and Potential on Power Transmission Line for 66kV

  • Nisiyama, Eiji;Kuwanami, Kenshi;Kawano, Mitsunori;Matsuda, Toyonori;Oota, I.
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.41-44
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    • 2003
  • We propose portable equipment that monitors current and voltage of high-potential power transmission lines. In the equipment, a current and voltage sensor are attached to an insulator that supports a power transmission line: A clamped to the power line and the detected current signal is transmitted to the ground station by a wireless optical link using transmission line is detected by a high resistance element, zinc oxide (ZnO). That acts as a potential divider between the power line and ground. We make an experimental device for 66kV power line and demonstrate that it can monitor currents proposed equipment is small-sized, light, and inexpensive in comparison with the conventional CT (current transformer) and PT (potential transformer) since it does not require high potential insulators and magnetic cores, further, the equipment is easily installed owing to its small size and its simple structure.

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The Best Line Choice for Transmission System Expansion Planning on the Side of the Highest Reliability Level

  • Sungrok Kang;Trungtinh Tran;Park, Jaeseok;Junmin Cha;Park, Daeseok;Roy Billinton
    • KIEE International Transactions on Power Engineering
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    • v.4A no.2
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    • pp.84-90
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    • 2004
  • This paper presents a new method for choosing the best line for transmission system expansion planning considering the highest reliability level of the transmission system. Conventional methodologies for transmission system expansion planning have been mainly focused on economics, which is the minimization of construction costs. However, quantitative evaluation of transmission system reliability is important because successful operation and planning of an electric power system under the deregulated electricity market depends on transmission system reliability management. Therefore, it is expected that the development of methodology for choosing the best lines considering the highest transmission system reliability level while taking into account uncertainties of transmission system equipment is useful for the future. The characteristics and effectiveness of the proposed methodology are illustrated by the case study using a MRBTS.

Resistance Distribution in Thin Film Type SFCL Elements with Shunt Layers of Different Thicknes

  • Kim, Hye-Rim;Hyun, Ok-Bae;Lee, Seung-Yup;Yu, Kwon-Kyu;Kim, In-Seon
    • Progress in Superconductivity and Cryogenics
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    • v.5 no.2
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    • pp.41-45
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    • 2003
  • Resistance distribution in thin film type SFCL elements of different shunt layer thickness was investigated. The 300 nm thick film of 2 inch diameter was coated with a gold layer and patterned into 2 mm wide meander lines. The shunt layer thickness was varied by ion milling the shunt layer with Ar ions, and also by having the shunt layer grown in different thickness. The SFCL element was subjected to simulated AC fault current for measurements. It was immersed in liquid nitrogenduring the experiment. The resistance distribution was not affected by the shunt layer thickness at applied voltages that brought the temperature of the elements to similar values. This result could be explained with the concept of heat transfer from the film to the surroundings. The resistance distribution was independent of the shunt layer thickness because thick sapphire substrates of high thermal conductivity dominated the thermal conductance of the elements.

Analysis of Lightning Overvoltage on the Underground Power Cable at the Striking of Lightning Surge to the Combined Transmission Line (혼합송전선로에 뇌서지침입시 지중송전선로에서의 뇌과전압 해석)

  • Kim, Nam-Yeol;Lee, Jong-Beom;Jang, Seong-Hwan;Gang, Ji-Won
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.10
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    • pp.502-509
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    • 2002
  • In the analysis of lightning surges, transmission towers are usually simulated by ATPDraw. The modeling of transmission towers is an essential part of the traveling wave analysis of lightning surges in transmission lines. The tower model is applied to the 154kV transmission tower of which surge performance characteristics are measured Tower surge response is computed using nonuniform, single-phase line models for both transmission tower and ground wire. The overvoltage will effect to the underground transmission line. The underground cable is combined by duct and trefoil type, and the each arrester is placed on the leading-in tube and outgoing tube. This paper analyzed the effect of lightning overvoltage on the underground cable system.

Two case studies on structural analysis of transmission towers under downburst

  • Yang, FengLi;Zhang, HongJie
    • Wind and Structures
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    • v.22 no.6
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    • pp.685-701
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    • 2016
  • Downbursts are of great harm to transmission lines and many towers can even be destroyed. The downburst wind field model by Chen and Letchford was applied, and the wind loads of two typical transmission towers in inland areas and littoral areas were calculated separately. Spatial finite element models of the transmission towers were established by elastic beam and link elements. The wind loads as well as the dead loads of conductors and insulators were simplified and applied on the suspension points by concentrated form. Structural analysis on two typical transmission towers under normal wind and downburst was completed. The bearing characteristics and the failure modes of the transmission towers under downburst were determined. The failure state of tower members can be judged by the calculated stress ratios. It shows that stress states of the tower members were mainly controlled by 45 degree wind load. For the inland areas with low deign wind velocity, though the structural height is not in the highest wind velocity zone of downburst, the wind load under downburst is much higher than that under normal wind. The main members above the transverse separator of the legs will be firstly destroyed. For the littoral areas with high deign wind velocity, the wind load under downburst is lower than under normal wind. Transmission towers are not controlled by the wind loads from downbursts in design process.

Kissing of Sub-conductors due to Magnetic Forces in a 154 kV Bundled Overhead Transmission Line (154 kV 복도체 가공송전선로에서 전자력에 의한 소도체간 접촉)

  • Kim, Sang-Beom;Noh, Hee-Won;Kim, Young-Hong;Ko, Kwang-Man;Park, Jong-Hyuk;Kim, Sang-Soo
    • KEPCO Journal on Electric Power and Energy
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    • v.2 no.3
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    • pp.383-389
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    • 2016
  • Kissing of sub-conductors due to magnetic forces has been investigated in a 154 kV bundled overhead transmission line. With increasing ampacity of the conductors and enlarging the distance between spacers, lager magnetic force was measured. When the phase ampacity was 2,000 amps and the distance between two adjacent spacers was 68 m, for instance, the conductors became unstable and vibrated with a frequency of several herts. Furthermore, when the ampacity was 2,250 amps and the distance between spacers was 136 m, the two sub-conductors were contacted. Analysing the magnetic forces with distance of spacers, the safe distance of spacers to avoid contact of sub-conductors was presented. The change of the safe distance is discussed due to various parameters, such as residual stresses and wind pressures, in the real transmission lines.

Analysis of Return Current for Rolling Stock Operation on Electrical Railroads (전기철도 구간에서의 철도차량 운행에 따른 귀선전류 분석)

  • Baek, Jong-Hyen;Kim, Yong-Kyu;Oh, Seh-Chan;Jo, Hyun-Jeong;Lee, Kang-Mi
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.9
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    • pp.4112-4118
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    • 2011
  • Electrical Railroads provide electric power, which can operate vehicles, via feeder wires. And the supplied current returns to the transformer substation through lines and ground net. The return current, related to signal, power and power line, and track circuit systems, is one of the most important component in the electric railway. Therefore, to prevent system faults and breakdown according to unbalance and overcurrent of the return current, various and detailed analyses for the return current are needed. In the paper, we present measurement and analysis manners in real environment and evaluate its safety. For analysis, we utilize the measured values of return currents measured in track circuits in electric railway. we expect that this research plays a key role to the related fields.