• Proceedings of the KIEE Conference
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.450-452
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• 1995

The Tree observation technique is being highlighted as a research area for deterioration of insulation because of high-voltage power system. For the measurement of tree, image processing is actively studied as a experimental technique of electrical tree, because the conventional directed visual method is impossible to analyze on tree degradation area and tree pattern. In this paper, we have developed the tree measuring system using image processing. By using an image processing technique, the treeing can be easily measured and effectively observed.

• Proceedings of the KIEE Conference
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1503-1504
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• 2015

배전용 케이블은 수트리 억제, 화재예방, 경제성 등을 고려하여 구조와 재질이 지속적으로 변경되고 있다. 변경되는 추세를 살펴보면 경제성 측면에서 도체의 재질은 동에서 알루미늄으로 변경되었고, 수트리 억제를 위해 절연체의 재질은 XLPE에서 TR-XLPE로 변경되었다. 또한 외피의 재질도 난연성을 강화하고 수분침투를 억제하기 위하여 난연성 PE로 개선하였다. 중성선도 외부반도전층 위에 올려진 구조에서 외피 내부로 들어가는 충실형 구조로 변경되었다. 이와 같이 외피구조가 변경되면서 외부반도전층의 두께가 증가되었고 이로 인해 접속재 시공시 삼각형 모양의 공극이 커지게 되었는데, 본 논문에서는 케이블의 외부 반도전층 두께 증가가 접속재 부분방전에 미친 영향을 고찰하였다.

• Proceedings of the KIEE Conference
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2060-2062
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• 1999

When the high voltage is applied on insulation materials that have voids and impurities inner one, then probability of electrical tree inception is increased at defects. Electrical tree gives a profit to degradation analysis, because it is possible to observe by eyes and provides electrical degradation step. And electrical tree is divided to three types in usual - tree type, bush type and chestnut type tree. But these three types are divided not by method of quantitative analysis but visual and experiential analysis. In this paper, three types of electrical tree were calculated by quantitative analysis using fractal mathematics and classified to fractal dimensions (FD). FD of tree types are 1.1$\sim$1.4, bush types are 1.4$\sim$1.6 and chestnut type trees have above 1.6 FD.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제11권7호
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• pp.502-507
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• 1998

The purpose of this study is to investigate the breakdown properties in joint interface of power cables with heat treatment. The specimens have the structure of XLPE/EPDM interface like the joint of distribution power cable. The breakdown characteristics of the SLPE/EPDM joint were studied with crosslinking by=products. AC breakdown voltages were measured with heat treatment time and interfacial materials and crosslinking by-products as testing factors. This study has shown that crosslinking by-product gases play an important role at the insulation properties of cable joints by heating. The dielectric strength shows the lowest values at 4 hours heat treatment. The AC breakdown strength in the untreated sample was increased with heat treatment time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.173-176
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• 1999

Crosslinked Decree is an important 7actor to determine dielectric property of crosslinked polyethylene(XLPE) used for the insulation material in Power cables. Recently, though it is necessary to investigate electrical properties according to crosslinked degree as a Part of the whose characterization of cable. it is not examined closely. In this study. crosslinked degree of samples were measured according to temperature and holding time of crosslinking. electrical tree characteristics of these characteristics of these samples were analyzed by crosslinked degree and applied temperature that was chanced from normal temperature to operating temperature of power cables. As a result. when the crosslinked degree was low, dielectric properties were decreased and influence of temperature was increased. but the crosslinked degrees were high, initiation voltages of treeing were increased and dielectric properties were improved. It is proved that the optimum crosslinked degree was one of most important factor for aging time and residual lifetime of Power cable.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제17권2호
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• pp.245-250
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• 2017

From the instant of installation and operation, power cables start deteriorating. Cable systems can be maintained not only by monitoring the insulation status of the insulation layer and oversheath, but also the insulation status of the terminal and junction in high-voltage power cables. When the cable system (the cable itself and cable junctions combined) deteriorates, fire accidents happen due to dielectric breakdowns. We have invented a device to monitor the deteriorating status of cables, and installed it at Korea Western Power Co. Ltd. located in Taean, Chungcheongnam-do Province. In this paper, we present the results obtained using our device, through analysing and calculating the standard deviation of leakage current from cable insulators attached to the cables. When the standard deviation of analysed leakage current falls below a critical value, a cable system is deemed to be operating safely. But when the standard deviation of analysed leakage current is larger than the critical value, the insulation status of the terminal and junction in the cable system is considered to have seriously deteriorated. The terminal and junction in the relevant system should then be replaced preemptively in order to prevent blackout accidents of cables caused by the suspension of power supply.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제59권5호
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• pp.847-853
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• 2010

This paper describes switching surge analysis for reclosing decision in 345kV combined transmission line with XLPE power cable. Reclosing operation should be decided based on the detailed technical analysis in combined transmission line because this line includes power cable section which is week on insulation. Insulation of power cable can be breakdown at the week point in case of reclosing moment. Therefore the detailed analysis has to be carried out by considering several conditions such as length ratio of power cable section, arrestor, inserting resistance, charging rate, grounding resistance, etc.. On the other hand sheath voltage on IJ(Insulated Joint) is analyzed to check dangerous condition on cable cover. Analysis is performed by EMTP/ATP. Analysis results show that reclosing can be operated as the single line-to-ground fault occurs on overhead line in 345kV combined transmission line, if the inserting resistance is considered before the operation of main circuit breaker.

• Proceedings of the KIEE Conference
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.539-540
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• 2011

본 논문은 154kV 지중송전선로의 가스중종단접속함(EBG)에서 발생한 절연파괴 고장을 분석하여 정확한 원인을 규명하고자 한다. 초고압케이블의 고장패턴을 분석한 결과 XLPE 케이블의 경우 10년 이내의 선로에서 시공불량 및 제작불량 고장이 집중되고 있는 경향을 보이고 있는 점을 감안시 이에 대한 대책마련이 시급한 실정이다. 따라서 본 논문에서는 국내 초고압 지중선로에서 발생한 고장사례 분석을 통해 향후 재발방지대책 마련에 활용하고자 한다.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제60권10호
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• pp.1811-1816
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• 2011

This paper describes switching surge analysis for reclosing decision in 345kV combined transmission line with GIL. Reclosing operation should be decided based on the detailed technical analysis in combined transmission line because this line includes power cable section which is week on insulation. Insulation of power cable can be breakdown at the week point in case of reclosing moment. Therefore the detailed analysis has to be carried out by considering several conditions such as charging rate, inserting resistance, arrester, length ratio of power cable section, grounding resistance, etc. Analysis is performed by EMTP/ATP.

• Proceedings of the KIEE Conference
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1447_1448
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• 2009

In this paper, each specimen blended at weight proportions of 80% HDPE to 20% EVA, 70% HDPE to 30% EVA, 60% HDPE to 40% EVA, and 50% HDPE to 50% EVA was manufactured respectively. The insulation performances of the proposed insulator were compared with conventional XLPE, main insulating material of CV cable on the basis of the investigation results of DC insulation performances. From the space charge density, electric field and potential profiles with raising DC voltage and time variation in HE82, distortion of electric field distribution was improved. As EVA mixed into the bulks acts as nucleation in crystallization process of HDPE, the size of spherulites became decreased and finally formed continuous network structure. Ultimately it resulted from extinction of space charge in the interfacial region of spherulites.