• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1475-1476
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• 2015

국내에서 XLPE 지중케이블이 처음 포설된 지 30년이 경과하였으며, XLPE 케이블의 수명은 일반적으로 30~40년 정도이기 때문에 케이블의 교체시기에 대한 문제가 대두되고 있다. 본 연구에서는 국내의 지중케이블 잔존수명평가 알고리즘의 장단점을 분석하고 국외의 잔존수명평가 알고리즘에서 국내 잔존수명평가 알고리즘의 단점을 보완할 점을 분석하였다. 또한 잔존수명 평가 알고리즘을 개선하는 것 외에 알고리즘에 사용되는 데이터의 통합 관리방안을 제시하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.228-231
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• 2002

In this paper, we estimated the insulation properties of cross-linked polyethylene (XLPE) for ultra-high voltage cable. we have studied the dielectric characteristics of XLPE due to frequency and temperature variation. The dielectric characteristics were measured in the temperature range from $25[^{\circ}C]$ to $120[{^{\circ}C]}$. Also we measured in the voltage range of 1[V] to 20[V] according to the step voltage application method. From FT-IR spectrum as an analysis of physical properties, a strong absorption in wavenumbers 700 to $730[cm^{-1}]$, $1456[cm^{-1}]$ and 2700 to $3000[cm^{-1}]$ observed by the methyl groups$(CH_{2})$. From the analysis of DSC, the crystalline melting points of the specimen observed in the temperature $60[^{\circ}C]$ and $106.58[^{\circ}C]$.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1564-1565
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• 2006

현재 전세계적으로 170kV급 이하의 초고압 지중케이블 접속함으로 기존의 현장몰드방식의 TMJ(Tape Molded Joint)와 부품조립방식의 PJ(Prefabricated Joint)보다 조립시간이 짧고 작업자의 숙련도가 높지 않아 경제적이며, 유지보수에 장점을 가진 고무몰드 접속함(PMJ)이 채용되고 있으며, 이러한 추세는 적용 전압급이 점차 상승하면서 230kV급까지 그 비중이 늘어나고 있는 경향을 보이고 있다. 당사에서는 이러한 추세에 발맞추어 154kV급 고무몰드접속함의 개발 당시의 Silicone의 기초물성시험 DATA 획득, 고무몰드 UNIT 및 금형 설계 기술 확립과 접속 공법 개발의 경험을 바탕으로 230kV급 고무몰드접속함의 개발에 성공하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1385-1386
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• 2007

전통적으로 초고압 지중케이블 접속함으로 현장에서 절연을 형성하여 전기적 성능을 유지하는 TMJ(Tape Molded Joint), TJ(Taped Joint), EMJ(Extruded Molding Joint) 및 공장에서 절연물을 가공하여 현장에서 조립만으로 설치를 완료하게 되는 PJ(Prefabricated Joint), PMJ(Pre-Molded Joint) 등이 사용되어 왔다. 최근에 PMJ에 사용되는 재료의 발전과 PMJ의 조립시간 단축, 원가 절감 및 공장 출하시 검사에 의한 신뢰성 향상으로 지중케이블 접속함 시장에서 PMJ의 비중이 점차 확대 되어가고 있다. 이에 당사는 이미 230kV급 PMJ의 개발을 완료하였으며, 이러한 기술적 배경을 바탕으로 현재 PMJ로서는 세계에서 최고 전압급에 속하는 400kV급 PMJ의 개발을 완료하게되었다.

• Journal of the Korea Computer Industry Society
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• v.3 no.12
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• pp.1651-1658
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• 2002

Recently power cable used generally in Korea, because installation is very simple and it has high stability. It confirms to the requirements of IEEE std. 404-1993 by factory testing, but many problems of insulated cable systems are caused by internal defects of the joint part which have to be mounted ensile. Especially, fault rates are arise from impurities or voids. A suitable solution for a monitoring of power cable during the after-laying test and service is partial discharge detection. The artificial defects between cable joint(EPR) and insulator(XLPE) interface are considered in this research to investigating the partial discharge characteristics. ${\varphi}$-q-n properties were detected using data acquisition system and Maximum charge($q_{max}$), repetition rate(${\={n}$), average charge(${\={q}$), Unbalance rate of ${\={n}$ and ${\={q}$ are calculated in order to analysis partial discharge properties quantitatively from this statistic value.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.187-193
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• 2018

There has been a gradual increase in the demand for the electric power in Korea. In order to meet the demand, power station should have technical functions with increased effectiveness. When accident happens in electric machinery at power stations, huge amount of economic losses and mulfunction of equipments occur. One of the accidents is a deteriorated cables operating power stations. In order to prevent cable accident in advance, we should monitor the insulation status of the cable. Cable accidents are resulting from the junctions. We have developed and installed a device in order to identify the status of junction part of power cable at Korea Western Power Co., Ltd.. We performed an accurate diagnosis for the stable utilization of junctions where the accidents occurs most frequently, and to increase the reliability. In this paper, we present the concepts of our device and the method of monitoring diagnosis for the stable use of junctions at cables predicting the life time of cables by analyzing the data obtained by the device. We also present the hardware aspect of the device we have developed.

• Transactions on Electrical and Electronic Materials
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• v.11 no.1
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• pp.42-47
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• 2010

Polymer insulating materials such as cross linked polyethylene (XLPE) are employed in electric cables used for extra high voltage. These materials can degrade due to chemical, mechanical and electric stress, possibly caused by voids, the presence of extrinsic materials and protrusions. Therefore, this study measured discharge patterns, discharge phase angle, quantity and occurrence frequency as well as changes in XLPE under different temperatures and applied voltages. To quantitatively analyze the irregular partial discharge patterns measured, the discharge patterns were examined using a statistical program. A three layer sample was fabricated, wherein the upper and lower layers were composed of non-void XLPE, while the middle layer was composed of an air void and copper particles. After heating to room temperature and $50^{\circ}C$ and $80^{\circ}C$ in silicone oil, partial discharge characteristics were studied by increasing the voltage from the inception voltage to the breakdown voltage. Partial discharge statistical analysis showed that when the K-means clustering was carried out at 9 kV to determine the void discharge characteristics, the amount discharged at low temperatures was small but when the temperature was increased to $80^{\circ}C$, the discharge amount increased to be 5.7 times more than that at room temperature because electric charge injection became easier. An analysis of the kurtosis and the skewness confirmed that positive and negative polarity had counterclockwise and clockwise clustering distribution, respectively. When 5 kV was applied to copper particles, the K-means was conducted as the temperature changed from $50^{\circ}C$ to $80^{\circ}C$. The amount of charge at a positive polarity increased 20.3% and the amount of charge at a negative polarity increased 54.9%. The clustering distribution of a positive polarity and negative polarity showed a straight line in the kurtosis and skewness analyses.

• Composites Research
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• v.35 no.3
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• pp.127-133
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• 2022

Polypropylene (PP) has been received great attention as a next-generation high-voltage power cable insulation material that can replace cross-linked polyethylene (XLPE). However, the PP cannot be used alone as an insulation material because of its high elastic modulus and vulnerability to impact, and thus is mainly utilized as a form of a copolymer with rubber phases included in the polymerization step. In this paper, a soft PP-based blend was prepared through melt-mixing of impact PP, polyolefin elastomer, and propylene-ethylene random copolymer. The elastic modulus and impact strength of the blend could properly be decreased or increased, respectively, by introducing elastomeric phases. Furthermore, the blends showed a high storage modulus even at a temperature of 100℃ or higher at which the XLPE loses its mechanical properties. In addition, the blend was found to be effective in suppressing the space charge compared to the pristine PP as well as XLPE.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.213-218
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• 2017

High-voltage power systems operate in order to generate and transmit electric power at power stations. Compared to low-power systems, high-power systems are complex in structure, large-scale, and expensive. When high-power cable accidents occur, most facilities are incapacitated-including low-power systems-causing huge economic losses. Great care must therefore be taken in designing, installing and managing power systems. Although dependent on installation circumstances and usage conditions, in some cases the cross-sectional areas of cables fall short of the critical area due to the expansion of and improper design and installation of power facilities. In this situation, the exceeded ampacity (allowable current) above the critical value caused by the operating current initiates the deterioration processes of power cables. In order to systematically monitor power cables operating at power stations, we have developed the first device of its kind in Korea. In this paper, we present the analyzed characteristics of expected temperatures of cables based on the load current of high-voltage cables operating at Korean Western Power Co. Ltd. We can predict the lifetime of cables by analyzing the temperature obtained from our device.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.231-236
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• 2014

With the development of industry these days, the demand for electric power increases and the larger capacity for power transfer is required. The scales of facilities should become larger; and the relative systems are required to operate with a higher degree of reliability. Therefore, stabilization of electric power systems is an important issue. The high degree of reliability required in the process of production and supply of electric power is an essential part of industrial society. Accident such as blackouts causes a hugh amount of economic losses to the high-tech industrial society dependent upon electric power. In this paper, in order to determine a stable operation of high-voltage power cable, used as a unique means of delivering electric power generated at a power station, we figure out the time rate of change of insulation resistance following a decay accelerating factor Arrhenius equation. With the data from the insulation resistance, we can determine the lifetime of power cable in operation.