• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.808-809
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• 2008

22.9kV 50MVA HTS power cable has been developed and tested by Korea Electrotechnology Research Institute and LS Cable Company and it was supported by a grant from Center for Applied Superconductivity Technology of the 21st Century Frontier R&D Program. In this paper, DC Ic of 100m HTS cable which is installed at Kochang testing station was measured and analyzed. A measurement technique of DC Ic used by resistance and inductance removal method is established. The HTS power cable is composed of 2 layers for transmission and 1 layer for shield. For the analysis of AC losses in an HTS power cable, 2-dimensional numerical calculation was carried out to define the magnetic field distribution. We calculated the magnetization losses in the HTS core of that cable from these fields. These calculated results are in accordance with those of experiment.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.697-699
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• 2005

High temperature superconducting (HTS) cable could be regarded as one of the most promising technologies for large electric power delivery with high reliability and low losses of power transmission system. Therefore, since 2001, LS Cable Ltd. has been developing 22.9kV, 50MVA HTS cable system as a member of DAPAS (Dream for Advanced rower system by Applied Superconductivity technology) program. In 2003, 22.9kV HTS cable system, single-core cable employing BSCCO HTS wires was firstly manufactured in 2003, and then three-core cable was also successfully developed through the demonstration of its field applicability. In this paper, based on these experiences, the relevant design technology and transient characteristics of HTS cable is described.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.266_267
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• 2009

22.9kV HTS(High Temperature Superconducting) cable and SFCL(Superconducting Fault Current Limiter) will be installed to Icheon 154kV substation for real distribution power system operation in 2010. This paper proposes CLR (Current Limiting Resistance) specification of the SFCL and fault current condition fo the HTS cable for applying to Korean power system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.242-242
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• 2007

To verify the applicability of High Temperature Superconducting (HTS) cable system into the real grid, the HTS cable system with the specification of 22.9 kV, 1250 A, 100 m long was installed in the second quarter of 2006, and the long term field test has been in progress at the KEPCO's Gochang power testing yard. Apart from the conventional power cable, HTS cable system requires sufficient thermo-mechanical strength to endure a large temperature difference. To date, the KEPCO HTS cable system was cooled down and warmed to the room temperature several times to investigate the influence of thermal cycles experimentally. Dielectric properties, critical current dependance and heat losses were evaluated at each step of thermal cycle. The test results showed that thermal cycle did not induce the degradation of dielectric properties, and the critical current decreased to 5 % of the initial value.

• Progress in Superconductivity and Cryogenics
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• v.11 no.3
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• pp.50-54
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• 2009

In Korea, 22.9kV 50MVA HTS (High Temperature Superconducting) cables and 630A/3kA hybrid SFCLs (Superconducting Fault Current Limiters) have been or are being developed by LS Cable, LS Industrial System, and Korea Electric Power Research Institute. They will be installed at Icheon 154kV Substation for real-power-distribution-system operation in 2010. This paper proposes specification of current limiting resistor/reactor for the SFCL and fault current condition of the HTS cable for applying the superconducting devices to Korean power distribution system, from the viewpoint of power system protection.

• Progress in Superconductivity and Cryogenics
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• v.11 no.3
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• pp.31-34
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• 2009

An HTS power cable is generally composed of 2 layers for conducting and 1 layer for shielding. For the analysis of AC loss of an HTS power cable, 2-dimensional magnetic field analysis is carried out. The magnetization loss in HTS cable core was calculated, and the transport current loss was obtained from the monoblock equation and the elliptical Norris Equation. And the total AC loss of the cable was expected by the sum of magnetization loss and transport current loss. The variation of ac loss with respect to the gap and uncertain factor between the superconducting tapes was investigated, and the ac loss of 22.9kV/50MVA high-Tc superconducting power cable was calculated. These results well agree with those of experiment.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.398-399
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• 2008

Enhanced performances of high temperature superconducting (HTS) cable attract tremendous interests of the power utility. However, the reliability issue as the power system is still in controversy. To verify the reliability of HTS cable, 22.9 kV HTS cable system with the specification of 100 m length, 50 MVA capacity, and open refrigeration cooling system was laid on Gochang power testing center of KEPCO in 2006. During the test period, the current transport characteristics, the fundamental function of power cable, have been monitored and investigated precisely. In this paper, the heat loss and AC loss measured at various current load conditions are described and discussed.

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.422-429
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• 2008

This paper presents compact low frequency ultra-wide band (UWB) sensor design and study of the partial discharge diagnosis by sensing electromagnetic pulse emitted from the partial discharge source with the newly designed UWB sensor. In this study, we designed a new type of compact low frequency UWB sensor based on microstrip antenna technology to detect both the low frequency and high frequency band of the partial discharge signal. Experiments of offline PD testing on medium voltage (22.9kV) underground cable mention the comparative results with the traditional HFCT as a reference sensor in the laboratory. In the series of comparative tests, the calibration signal injection test provided with the conventional IEC 60270 method and high voltage injection testing are included.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.2
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• pp.107-113
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• 2008

In 22.9[kV]-y distribution systems, underground cables are provided with multiple-point ground in which each coaxial-neutral line of the distribution cable lines(A, B, C phases) is 3-wire common grounded. In the underground cable distribution systems, circulating current flows in the coaxial-neutral lines and its magnitude amounts to about $40{\sim}50[%]$ load currents, even though loads are balanced. Power loss due to the circulating current consequently reaches to about 76[%] total losses occurred in all conductor lines. This power loss provokes additional temperature rise of the underground cable lines and finally results in 20[%] reduction of the current capacity of the cables. This paper presents a new ground method to overcome such a problem. The proposed method eliminates the circulating current flowing in the coaxial-neutral line effectively. Measurement results confirmed from the practical site-test show validity and effectiveness of this research.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1549-1551
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• 2001

Cyclic aging for 14 days is performed to remove a large amount of the volatiles found in freshly manufactured cable. In this paper, we examined lightning impulse characteristics of 22.9 kV CV power cable before and after cyclic aging for 14days. As the result, the breakdown voltage after aging under normal temperature was lower than that before aging, and the breakdown voltage after aging under hot temperature was lower than that before aging. We found that the dispersion of lightning impulse breakdown voltage before 14 cyclic aging test were reduced rather than those after 14 cyclic aging test.