• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.432-435
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• 2003

최근 초고압 케이블 절연체로 XLPE(가교 폴리에틸렌)이 널리 사용되어 지면서 XLPE의 여러 물리 화학적 특성에 따른 절연 성능에 관한 연구가 활발히 이루어지고 있다. 이러한 XLPE 절연층은 제조과정에서 압출과정을 거쳐 도체를 감싸게 되는데 이 과정에서 흐름 패턴으로 나타나는 비등방성(anisotropy)을 띠게된다. 본 논문에서는 초고압 XLPE 케이블에서 시계 방향으로 나타나는 비등방성(anisotropy)이 나타내는 기계-전기적 특성을 인장강도(tensile strength), 트리 개시전압 및 개시시간을 측정한 결과를 토대로 고찰해 보았으며, 이러한 비등방성이 초고압 XLPE 케이블의 절연 성능에 영향을 주는 인자로 고려되어야 함을 알 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.84-87
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• 2001

In this paper, degradation and dielectric properties of XLPE sheets moved from 22/154kV power cables were investigated. At the results of dielectric property of 22kV/154kV XLPE sheet, We earned that $tan{\delta}$ is $7.4{\times}10^{-4}$, $2.15{\times}10^{-4}$ and dielectric constant is 2.3, 2.24. Temperature dependance of $tan{\delta}$ inclined to increasing with temperature and increase of $tan{\delta}$ of 22kV XLPE sheet is higher than it of 154kV XLPE sheet. And increasement of XLPE sheet with water is higher than it without water.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.219-222
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• 1998

In this study, The water tree characteristics were investigated when crosslinking coagent was added in XLPE/EnBA blends. When XLPE was blended with EnBA, there was a decrease of water tree length as an increase of nBA contents in XLPE/EnBA20 blends. The effect of crosslinking coagent. A was better than those of other crosslinking coagents B, C and D in water tree retardation. In case of XLPE/EnBA/Crosslinking coagent blends, water tree length was increased as the crosslinking coagents were increased from 0.2 to 2 phr in 2.0 phr DCP content. To clarify the effects of crosslinking coagent, the DCP contents were changed from 1.5 to 2.0 par in the same crosslinking coagent contents. Then, there was a decrease of water tree length as an increase of crosslinking coagent contents in 1.5 and 1.8 phr DCP contents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1060-1069
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• 1998

Electrical properties such as space charge accumulation and water tree length and physical properties such as tensile strength, elongation and degree of crosslinked polyethylene (XLPE)/ethylene n-butyl acrylate copolymer (EnBA) blends were investigated. It was found that electrical properties such as water tree length grown at a specific condition and AC breakdown strength are improved by blending the XLPE with EnBA. The EnBA having higher nBA content showed the better electrical properties in XLPE/EnBA blends. A further improvement of these properties was achieved when a small amount of crosslinking coagent was used in the preparation of XLPE/EnBA blends.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.75-80
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• 2006

In this paper, to detect and observation the void discharges pulse signal, AE signals and tree growth characteristics in case the high voltage is applied to a XLPE sample for a power cable. We also examined the partial discharge current pulse and AE signals with the increase of the applied voltage in XLPE insulation. The experimental results show that a branch-type tree grows in the presence of the voids, and a bush-type tree grows in the absence of the voids in both samples. A rate of tree growth increases abruptly in proportional to the deterioration time in the presence of the of the voids, but in the absence of the voids, a rate of tree growth decreases as time goes by and finally a breakdown occurs. The frequency band of AE signals that are generated from the partial discharges in a XLPE sample, one of solid dielectric materials, is about 1.0[MHz].

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1356-1358
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• 1995

About 20 years have passed since cross-linked polyethylene(XLPE) came into practical use for power transmission cables. In 1969, We were the first to product 33kV XLPE insulated cables, and in 1984 produced XLPE cable for 154kV. To meet the increasing demand for electric power in large cities, and to improve reliability of the power supply, plans are being made to introduce ultrahigh-tension power cable for long distance underground lines in urban areas. Studies are currently under way to develop more than 154kV XLPE cables to meet increasing demand. In this paper presents the progress in the production and design of XLPE cables, and describes ways in which further improvements seems likely.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.6
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• pp.466-469
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• 2001

In this paper, we evaluated the dielectric properties of XLPE sheet of 22kV power cable, XLPE/semiconductor and XLPE/water/semiconductor depended on electric field and temperature respectively. Dielectric properties and temperature dependency of XLPE sheet of 22kV power cable increase greatly with as temperature increase and have no effect on applied voltage. And we confirmed that tan$\delta$ values in the samples with semiconductor or water layers were higher than those in the samples without them.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.77-80
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• 2000

In order to determine what influences the interfacial charge in EPDM/XLPE laminates, We used PEA (pulsed electroacoustic) method. Interfacial properties such as space charge accumulation and breakdown strength in crosslinked polyethylene (XLPE)/ethylene-propylene-diene monomer (EPDM) laminates were investigated. Interfacial charge develops when the EPDM is laminated with XLPE. It showed the positive polarity same as the simulation in case on intercase of EPDM/XLPE. In case of coupling agent added silicone oil, as increasing the content of coupling agent, the interfacial charge decreased. Details of the results are given and their origins discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.211-214
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• 1998

DC breakdown characteristics and formation of space charge at the interfaces of crosslinked polyethylene (XLPE) /ethylene propylene diene terpolymer (EPDM) laminates were studied. Effects of silicone grease and some chemicals such as crosslinking coagent on the interfacial charge were also studied. Interfacial charge develops at the interface of XLPE/EPDM laminates, which changes depending on heat treatment conditions and types of chemicals coated at the interface. Some chemicals such as maleic anhydride reduce the accumulation of interfacial charge in the XLPE/EPDM laminates. Breakdown strength of EPDM/XLPE laminate through the interface was highest when silicone oil was pasted in the interfaces. Interfacial breakdown strength decreased with the increase of MAH content.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1273-1275
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• 1998

The main faults at cable joint are mainly originate from double layered structure, which is composed of different kinds of materials such as XLPE/EPDM laminatest. In this paper, to investigate the effect of interfacial condition and coagents on dielectric strength of XLPE/EPDM, we prepared XLPE/grease/EPDM, XLPE/grease + coagent/EPDM laminates. Dielectric strength of the XLPE/EPDM laminates pasted with the grease compounded crosslinking coagent (TMPTA, TMPTMA) is higher than that of the laminates paseted with the grease without coagent.