• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.205-209
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• 2015

The economic losses resulted from the accident in the power cables at the power station is not only huge but also requires a great amount of time and expenses to restore to the former condition. In order to prevent these, it is necessary to invent and apply a technique to expect and prevent the accidents. In order to measure insulation resistances of power cables in operation, we derived the relations between load current and temperature. By analyzing data obtained from our measuring equipments, we showed the expected time to change deteriorated cables before accident occurs. We present a result of our study on the effects of the load current on lifetime of 6.6 kV cable systems in operation. With the current flowing through the load of the cable a heat is generated reducing the lifetime of the cable. In order to find out the effect of load current on the lifetime of cable systems, we applied the lifetime theory to the development of two equipments to measure insulation resistance and current of cable systems in operation.

• Transactions on Electrical and Electronic Materials
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• v.9 no.5
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• pp.186-192
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• 2008

Cross linked polyethylene (XLPE) insulators are used as insulation in ultra-high voltage electric power cables. This study investigated the electrical properties of XLPE at different temperatures. The electrical properties of the changing tree phenomenon was examined as a function of temperature applied to the electrical conductors by measuring the partial discharge at $25^{\circ}C$ to $80^{\circ}C$ and applied voltages to the electrodes ranging from 1 kV to 40 kV. The activity of the partial discharge was examined at various temperatures using the K-means distribution. The results revealed the specimen at $80^{\circ}C$ to have the lowest inception voltage and breakdown voltage. In addition, the core of clusters was moved $0^{\circ}$ and $180^{\circ}$ at the positive region and $180^{\circ}$ and $360^{\circ}$ in the negative region in the K-means. The distribution of clusters was concentrated on the inception condition and spread out widely at the breakdown voltage.

• 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.

• Proceedings of the KIEE Conference
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• 2004.11d
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• pp.53-55
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• 2004

부분방전 검출을 이용한 XLPE 케이블 진단은 중간 및 종단 접속재의 계면에 존재하는 결합을 검출할 수 있는 가장 효과적인 방법으로 제시되고 있지만 현장의 큰 노이즈로 인하여 신뢰성 있는 진단이 쉽지 않다. 하지만 국내에서 많은 연구가 이루어진 송전케이블 진단 기술을 바탕으로 배전케이블 진단에 적용하여 종단접속부에서 발생된 부분방전을 성공적으로 검출하였고 해체 조사를 통하여 결함을 검출하였다. 본 논문은 참고문헌[1]에 발표한 논문에 연결되는 논문으로 전편은 2004년 2월 부분방전 검출사례를 보고한 논문이고 본 논문에서는 8월 계획정전을 통하여 문제된 접속함을 교체한 후 해체조사를 통하여 결함을 검출한 사례보고이다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1604-1605
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• 2011

This paper deals with the partial discharge detection in order to recognize with three different nature of artificial defects using non-conventional HF-VHF PD sensor of which two measuring position are chosen along the 22.9kV XLPE power cable specimen. The response of the sensor under investigation has been observed be significantly affected by the cable length from the PD sources. As a result, it seems that the detecting sensor position is very important for the analysis of the nature of PD source. Moreover, it could be suggested that any standardized calibration method should be established replacing IEC 60270 as far as any type of non-conventional sensors are concerned.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2014-2016
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• 2000

In order to meet recent increasing demand for electric power in large cities, plans are being made to introduce 345kV lines into large urban areas. Up to now, OF cables have been used for 345kV fines, but nowadays XLPE insulated cables are preferred as they are easier to maintain due to phenomenal advances in plastic insulation technology, therefore cable manufacturing companies are trying to improve the performance and reliability of UHV CV cables and their accessories. For the purpose, our company has developed facilities for testing UHV cables. In this paper, we describes the methodology adopted for the design and development of a test termination, conducted the electrical test of UHV cables. Based on detailed analytical studies for electrical field distribution, the internal electrical design for the testing end has been carried out.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.214-218
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• 2008

Because on the high-tension underground distribution line of an electric railway high voltage XLPE Cable two or three circuits between railway stations with a standard as receiving transformer facilities are established at a $30km{\sim}50km$ interval, reactive power in which the phase of a current is larger than that of a voltage is supplied when trains are not working, so when there are no loading or low loading as night. Due to the long-distance trend of the underground distribution system on an alternating current railway distribution line, the terminal voltage of a transformer is over the standard voltage, and after all, commercial cycle overvoltage is continued. To solve this problem, the shunt reactor is installed in middle of power distribution lines to maintain receiver voltage meted under the allowance regulation through control of the reactive power. Also, in case that the thickness of single cable is over $60mm^2$ and length of line is about over 30km, a circuit breaker is broken by shorting shunt ability of charging current in excess of shunt current(31.5A.rms). Therefore, this thesis presents installing the location of shunt reactor for quantitative analysis by using optimum algorism for compensation and control of the charging current.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.373_374
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• 2009

대도시 전력계통망을 구성하는 지중송전선로는 154kV, 345kV OF 및 XLPE 케이블로 구성되어 있으며, 국토개발 및 도심지의 확장에 따라 설비물량은 갈수록 증가되고 있다. 국내 전력케이블은 대용량화, 소규모화 등 지속적으로 기술개발이 추진되고 있으며, 케이블 및 전력구 온도를 실시간 감지하여 운영자에게 보여주는 감시시스템도 도입되어 안정적인 전력공급을 위한 기반도 구축되었다. 최근 설비량 증가 및 대기 온도상승으로 인한 케이블 송전용량의 제한을 해소하기 위해 국내 최초로 냉각시스템을 도입할 예정이다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1497-1498
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• 2011

본 논문에서는 -50[$^{\circ}C$]환경에서 케이블 접속함의 극한지역 적용가능 여부를 확인하기 위해 접속함의 주재료인 Etylene Propylene Rubbe(EPR), Silicone Rubber(SR) 및 Epoxy의 물성 및 특성 평가 시험을 진행하였다. 실험방법은 DSC(Differential Scanning Calorimetry)를 사용하여 10[$^{\circ}C$]/min의 승온속도로 각각의 온도구간에서 샘플들의 Tg(Glass Transition Temperature)를 측정하였고, UTM(Universal Testing Machine)으로 -50[$^{\circ}C$]~ 상온에서 인장강도 및 신율을 측정하였다. 본 연구를 동하여, 극한지역의 전력계통 연계 안정성 및 신뢰성 향상을 위한 기초적인 Data-base를 구축했다.

• 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.