• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.148-151
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• 2002

In order to prevent the failures of underground distribution power cables we need to measure insulation condition in the field. Until now we used DC high voltage as a power source for the cable diagnosis but it was not proper method to the XLPE insulation cables because DC high voltage can affect sound insulation and can't diagnose exactly insulation degradation. For these reasons we imported isothermal relaxation current measurement system called by KDA-1 from germany but it's reliability did not proved in our URD cables. DC voltage decay measurement system was developed by domestic company but they don't have field experience. In this paper we tried to prove reliability of these two systems in the field. Through the field diagnosis and Ac breakdown test the two systems showed similar results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.502-505
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• 2004

The purpose of this experiment is to modify diagnosis criterion of isothermal relaxation current(IRC) measurement equipment which is using for distribution cable diagnosis. We're using this system for several years in the field instead of DC leakage current measurement and lots of cables were replaced. But we have to investigate on the reliability of this equipment for our cables because we didn't carried out condition assessment of extracted cables after field diagnosis by this equipment. It is important thing for cable maintenance. If the replacement criterion is improper we can not prevent failures or will waste budget on account of replacement of the sound cables. In this papar we selected field installed cables and injected silicone fluid to the cables for insulation rehabilitation. In order to prove reliability of the diagnosis equipment we compared diagnosis results and AC breakdown strength according to operating time after silicone treatment. This is the results of the field test for 1 year.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.5
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• pp.258-263
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• 2004

The purpose of this experiment is to modify diagnosis criterion of isothermal relaxation current(IRC) measurement equipment which is using for distribution cable diagnosis. We're using this system for several years in the field instead of DC leakage current measurement and lots of cables were replaced. But we have to investigate on the reliability of this equipment for our cables because we didn't carried out condition assessment of extracted cables after field diagnosis by this equipment. It is important thing for cable maintenance. If the replacement criterion is improper we can not prevent failures or will waste budget on account of replacement of the sound cables. In this paper we selected field installed cables and injected silicone fluid to the cables for insulation rehabilitation. In order to prove reliability of the diagnosis equipment we compared diagnosis results and AC breakdown strength according to operating time after silicone treatment. This is the results of the field test for 1 year.

• 전기의세계
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• v.26 no.6
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• pp.86-92
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• 1977

The phenomenon of non-steady-state current flow through the interface traps during the dielectric relaxation of MOS device is presented. Experimental method is also described for determining the energy distribution of interface traps, which is based on isothermal dielectric relaxation current technique. Actually, the energy distribution of interface traps was obtained by measuring the transient current through the traps at Si-SiO$_{2}$ interface only in lower-half of the bandgap. It is shown that the trap energy distributio has peak value 1.72*10$^{13}$ cm$^{-2}$ eV$^{-1}$ near 0.73eV approximately.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1569-1571
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• 1999

In this work, we have performed the application experiment for real distribution line to diagnose the underground power cables using DC voltage decay measurement system. We have also performed the Isothermal Relaxation Current test for the same distribution line using KDA-l. We could confirmed possibility of grading the insulation aging state of underground power cables. Therefore, we conclude that it is possible to apply DC voltage decay method to the real distribution line.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.304_306
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• 2009

본 논문은 IEEE std 400에서 규정하고 있는 케이블 시험방법 중 Type 1, 파괴시험법(DC, 상용주파 내전압, 그리고 VLF내전압 시험)은 절연물 손상을 발생시키므로 예방진단에 사용될 수 없고 그렇지 않은 Type 2. 비파괴시험법에 대해 주로 소개하였다. 이와 추가하여 한전에서 사용 중인 IRC(Isothermal Relaxation Current) 측정법에 대해 간략하게 소개하고 더불어 IEEE Std 400에서 제시하고 있는 $Tan{\delta}$측정법의 문제점 및 개정 방향을 소개하고, 마지막으로 IEEE Std 400.3의 PD신호의 분석을 통해 결함위치와 열화정도를 평가 진단하는 기법에 대해 서술하고저 한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.484-487
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• 2000

This study is for assessing a reliability of diagnostic device through comparing diagnostic results to ACDB strength. The dielectric diagnosis using IRC (isothermal relaxation current) measurement was carried on service-aged cables. From this study, there was little correlation between dielectric diagnosis and ACBD strength in long distance cables. But the correlation between them showed in short distance below 200 m. Therefore, it is desirable to diagnose the URD cables in short distance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.468-471
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• 2003

Fault of under ground power cable occurs usually from the water tree such as the vented tree, the bow tree and the water-rich halo. The water tree penetrates to the polyethylene cable insulations. Sometimes, the water tree also diffuses to mother cable in the substation. In this paper, instead of replacement of the faulty cable, we tried to cure an electrical power cable degraded by the water trees with silicon injection method. And measured the results with the isothermal relaxation current analysis method. After cable cure, Chonil line was improved from 2.27 to 1.96 in a phase, from 2.148 to 2.020 in b phase, and from badness to 2.192 in c phase. And Keumam line was also improved from 2.419 to 1.920 in a phase, from 2.301 to 2.000 in b phase, and from badness to 1.957 in c phase.