• Proceedings of the KIEE Conference
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• summer
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• pp.619-621
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• 2004

This paper presents the rapid and accurate algorithm for fault discrimination in transmission lines. When faults occur in transmission lines, fault discrimination is very important. If high impedance faults occur in transmission lines, it cannot be detected by overcurrent relays. The method using current and voltage cannot discriminate high impedance fault. Because of this reason this paper uses voltage and zero sequence current, and the proposed algorithm uses fuzzy logic method. This algorithm uses voltage and zero sequence current per period in case of faults. Single line ground fault and three-phase fault can be detective using voltage. Two-line ground fault and line to line fault and high impedance can be detected using zero sequence current. To prove the performance of the algorithm, it test algorithm with signal obtained from ATPDraw simulation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.2
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• pp.59-61
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• 2006

In our country most of transmission lines are double-circuit lines. In these lines, the combining method of increasing conductor height and installation of passive shield-loop to mitigate magnetic field near a transmission line, is a good and feasible method. The basic principle of passive shield loop is that the field from the current induced in the shield loop conductors counteracts the field from the phase conductors. This method applied to domestic transmission lines to meet the magnetic field level, 100, 30, 10 and 4 mG, respectively. In each magnetic field level, the minimum conductor height and passive loop height are presented for the implementation of the practical design.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1088-1090
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• 1999

The radio noise produced by corona discharge in high voltage transmission tines is one of the most important line design considerations. Therefore it is necessary to pre-evaluate radio noise for transmission line designers using Prediction formulas or field test results. In this Paper, more accurate and useful formulas for Predicting radio noise during fair and foul weathers in AC transmission lines were proposed through comparison with the existing formulas. Also it was verified by comparing with the long-term measured data from operating lines that the Proposed formulas are very accurate. The Proposed prediction formulas are developed by the applications of nonlinear least square optimization method to radio noise database collected from lines throughout the world.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.978-979
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• 2006

Recently, Peoples are exposed the ELF(Extremely Low Frequency) magnetic fields in the vicinity of underground transmission lines, and there are the generally accepted opinion that the magnetic fields affect the human body and there are possibility of the disease. Also in relation to this problem, technical solution methods and research are advanced for reducing the magnetic fields. In this paper, to practically understand the magnetic fields underground transmission lines, We analyze the electromagnetic field distribution in the underground transmission lines by means of FEM(Finite Element Methods) and present that improvement of the effective shielding methods by applying cable arrangements and shielding materials, eddy current problem to the underground transmission lines by means of the numerical analysis Tool.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.1
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• pp.25-30
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• 2005

An accurate digital distance relaying algorithm which is immune to mutual coupling effect and reactance effect of the fault resistance and the load current for the line faults in 765kV untransposed transmission lines is proposed. The algorithm can estimate adaptively the impedance to a fault point independent of the fault resistance. To compensate the magnitude and phase of the apparent impedance, this algorithm uses the angle of an impedance deviation vector. The impedance correction algorithm for phase-to-ground fault and phase-to-phase short fault use a voltage equation at fault point to compensate the fault current at fault point. A series of tests using EMTP output data in a 765kV untransposed transmission lines have proved the accuracy and effectiveness of the proposed algorithm.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.245-247
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• 1998

Compacting of Overhead power transmission lines can be helpful in solving many problems, such as reduction of land and forest losses. decrease of the line's environmental impact zones, improvement of its electrical performance. And in overhead transmission lines, regular polygon configuration of bundled conductors are considered and adopted. This papers are compared to subconductor surface charges and electric field gradients, line parameters, natural capacities for regular polygon and modified configurations in 345kV 4 bundle 2 circuits horizontal type transmission lines.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.1009-1014
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• 2007

A detailed study on aged sleeves for old transmission lines was carried out to clarify the deterioration of sleeves and the condition of installation. A lot of removed aged sleeves from transmission lines were investigated. Many biased installed cases and corrosion of steel sleeve part were found. These defects can cause a serious accident such as blackout during operating. The temperature distribution within sleeve of ACSR conductor was precisely measured and examined, conducted as part of series of studies on large currents in transmission lines. According to measurements of the conductor temperature near a joint(sleeve and clamp), the electrical resistance of joint is lower than that of the same length conductor. The detailed results were presented in the text.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.8
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• pp.412-417
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• 2000

TV ghost interference can be described as passive interference by the conducting part of transmission lines. In order to survey this interference from large-sized overhead EHV (extra high voltage) transmission line, TV reception quality was measured in the vicinity of that before and after construction. Instrumentation system was composed of ghost analyzer, TV received field intensity meter, VHF/UHF antennas, TV monitor and so on. The system is installed inside the vehicle. TV field intensity and PDUR (Perceived Desired wave to Undersired wave Ratio) are measured to evaluate TV ghost by using the system and vehicle. As the results, the useful data, which can be used to evaluate the effect of TV ghost interference from transmission lines could be obtained. In this paper, it is shown that the range of TV ghost interference from transmission lines can vary according to the frequency of TV electromagnetic wave, an incidence angle to the line and the other conditiions. At present, we are making efforts to establish a PDUR guideline for transmission lines.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.36-38
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• 2004

In many countries, including Korea, in order to transmit the more electric power, the higher transmission line voltage is inevitable. So, a rapid reclosing scheme is important for UHV transmission lines to ensure requirements for high reliability of main lines. But, because of the high voltage and long span of UHV lines, the secondary arc current flows across the fault point even after the interruption of the fault current. i.e. A critical aspect of reclosing operation is the extinction of the secondary arc since it must extinguish before successful reclosure can occur. In Korea transmission lines, it is scheduled to energize 765kV single transmission line(79km) between Sin-Ansung S/S and Sin-Gapyeong S/S at June 2006. Therefore this paper analyzes characteristics of the secondary arc extinction on 765kV single transmission line using EMTP. Simulation results shows that the average value of the secondary arc is $30A_{rms}$ and the auto-extinction time of it is longer at closer point to Sin-Gapyeong S/S.

• Journal of the Korean Society of Clothing and Textiles
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• v.46 no.2
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• pp.367-374
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• 2022

Herein, a highly elastic e-textile band with a two-wire transmission line was designed and fabricated for smart clothing applications. A conductive yarn with a very uniform low electrical resistance of 0.0357 Ω/cm was developed and used for the signal and ground lines. To control the elasticity of the e-textile band, spandex yarns were added in the warp direction during knitting and the tension was adjusted. As the length of the e-textile band increased, its RF performance deteriorated. Furthermore, the frequency corresponding to -3 dB S21 was lower in the 30% stretched band than in the unstretched band. For the e-textile bands with lengths 10, 50, and 100 cm, the frequencies corresponding to -3 dB S21 were 107.77, 24.56, and 13.02 MHz when not stretched, and 88.74, 22.02, and 12.60 MHz when stretched by 30%. The fabricated bands were flatter, more flexible, and more elastic than transmission line cables; thus, they can be easily integrated into wearables and smart clothing. However, to increase RF performance and achieve optimum utilization, future studies must focus on the fabrication of transmission lines with lower resistance and reduced distance between the signal and ground lines, and thus the number of transmission lines can be increased.