• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.4
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• pp.161-166
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• 1999

We have performed an EMTDC simulation for the current limiting effects of a superconducting fault current limiter (SFCL). The fault currents in the 154 kV transmission line between the arbitrary S1 and S2 substations increased up to 39 kA during the single and double line-to-ground faults, respectively. The SFCL in the transmission line is sufficient.

• Journal of IKEEE
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• v.16 no.1
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• pp.1-6
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• 2012

Thermal rating or lifetime evaluation for aged overhead transmission line becomes more important concerns with respect to keeping power delivery stable having proper capability. Both load rating and dip/clearance are essential factors to determine transmission capacity. In order to evaluate thermal rating and conductor lifetime for domestic transmission lines with double-circuit, the dip/ground clearance standards as well as the electrical equipment technical standard are examined. Conductor temperature and dip are calculated under the assumption of a contingency, and then, a method to up-rate load capacity is searched. As thermal rating and limit dip for aged conductor are properly evaluated, an improved strategy in order to guarantee the existing power system reliability is presented in this paper.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.276-278
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• 1996

The breakdown Process in large gaps is greatly influenced by the gap geometry. Therefor full scale test are essential for the economical and reliable air insulation design. For switching surge design of 765 kV double circuit transmission line KEPRI is carrying the verifying tests using impulse voltage generator at Gochang test site. In this paper, the intermediate results of verifying tests are presented and the switching surge design criteria of 765 kV transmission tower flashover paths are discussed.

• Journal of KSNVE
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• v.6 no.1
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• pp.89-95
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• 1996

If the transmission line voltage is greater than 500kV, audible noise (AN) and hum noise (HN) due to corona discharges on the conductor would be an important design factor for the conductor selection of transmission line. Also there is an aeolian noise: wind noise(WN) from the tower and the conductor due to wind. This paper presents the results of a statistical analysis of audible noise, hum noise, aeolian noise of 6-480mm$^{2}$ conductor bundle in KEPRI 765kV Test Transmission Line which was constructed to develop 765kV double circuit AC transmission line for the first time in the world. The result of the analysis shows that 6-480mm$^{2}$ conductor bundle and tower satisfy configuration the audible noise design criterion of 50dB(A).

• Journal of the Korean Ceramic Society
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• v.40 no.4
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• pp.375-379
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• 2003

In this paper, a novel design of multilayer ceramic-based Transmit/Receive (T/R) switch using Low Temperature Co-fired Ceramic (LTCC) technology have been presented. Compact T/R switch has been designed by transforming quarter-wave transmission line to its lumped equivalent circuit. Especially, high-Q three dimensional inductors with double strip have been proposed and incorporated. The proposed inductor has been modeled by multi-conductor coupled lines. A measured inductor quality factor (Q) of 80 and a Self-Resonance Frequency (SRF) of 6.6 GHz have been demonstrated. The inductor library has been incorporated into the design of WCDMA T/R switch.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.332-334
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• 2003

The direction and the type of a fault on a transmission line needs to be identified rapidly and correctly. This paper presents a approach to identify fault direction and type with neural network on double circuit transmission line. A neural network based on self organization map(SOM) provides the ability to accurately classify the fault type and to select of a fault direction. In this paper, proposed algorithm uses different patterns of the associated voltages and currents in order to identify fault clusters.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.254-258
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• 2001

In this paper, 3-dimensional charge simulation method was developed to analyze electric field distributions of special conductor bundles equipped with spiral rods for reducing aeolian noise. When we applied this method to 765 kV double circuit transmission line, we found calculation error of this method was within a reasonable boundary of 1%.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.452-454
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• 2001

This paper described the calculation results of lightning flashover rate on the 345kV and 154kV transmission system of KEPCO. The back-flashover rate and shielding failure rate was calculated by FLASH(lightning flashover rate calculation program from IEEE) and KEPRI's own program which is based on the EGM(Electro Geometrical Model) method. The estimated lightning flashover late of 345kV transmission system of double circuit was 1.0 flash per 100km-year, and the lightning flashover rate of 154kV transmission line was 2.0 flash Per 100km-year approximately.

• Journal of IKEEE
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• v.18 no.4
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• pp.442-446
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• 2014

A method for applying emergency ratings to improve the reliability of power supply in ACSR overhead transmission lines is described in this paper. Due to re-regulate power industry, most power companies worldwide as well KEPCO have been searching for only economical strategies without new investment. Power demand was rapidly increasing, however, generation amount did not follow sufficiently. Hence in order to increase the transmission capacity for the existing transmission lines in case of peak load, or contingency in transmission lines, an application method of emergency ratings such as short or long term rating is proposed. If applying long term emergency rating instead of static line rating for the period of a peak load, power transmission can be increased to 10 % or more. Furthermore, it was shown that emergency rating can be effectively used in the contingency of double-circuit transmission lines and/or overload cases.

• ETRI Journal
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• v.28 no.1
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• pp.84-86
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• 2006

This letter presents a small-sized, high-power single-pole double-throw (SPDT) switch with defected ground structure (DGS) for wireless broadband Internet application. To reduce the circuit size by using a slow-wave characteristic, the DGS is used for the quarter-wave (${\lambda}$/4) transmission line of the switch. To secure a high degree of isolation, the switch with DGS is composed of shunt-connected PIN diodes. It shows an insertion loss of 0.8 dB, an isolation of 50 dB or more, and power capability of at least 50 W at 2.3 GHz. The switch shows very similar performance to the conventional shunt-type switch, but the circuit size is reduced by about 50% simply with the use of DGS patterns.