• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.10
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• pp.672-676
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• 2017

Electrical energy is playing an increasingly vital role as the primary energy source in everyday life. With the increase in electric power consumption, power facilities are under an increasing stress and must operate at a high capacity. Consequently, the demand for electric power cables in power transmission and distribution lines is rapidly increasing. Underground distribution lines have been steadily replacing the aboveground lines owing to the increase in electric power demand and the need to increase the supply voltage. In addition to line damage, worker safety is of primary concern in this type of underground infrastructure. In this study, to improve the safety of workers dealing with underground transmission lines, we analyzed the electromagnetic field generated around the distribution line and determined the basic criteria for developing a device that can detect a live underground line.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.77-83
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• 2012

Since power system is switching to smart grid, on-line monitoring technology has become necessary for underground distribution power cable. Therefore, the application of DTS(Distributed Temperature Sensing) technology using OFCPC(Optical Fiber Composite Power Cable) capable of monitoring underground distribution power cables has been developed. These can bring about reductions in faults and increases in operating capacity of underground distribution system. To date, the test-bed of optical fiber composite power cable on-line monitoring system has been constructed. Then, matters to be improved have been drawn through verification experiments. This paper presents the improvement and experiment results of the optical fiber composite power cable on-line monitoring system to apply to underground distribution lines in the field.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.204-205
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• 2006

This paper describes the protective ability of lightning arrestor in combined distribution system with power cable. To evaluate the protective ability, change of arrestor and grounding location are considered. On the other hand, arrestor developed by Cooper Power Systems for underground power cable system, is considered to evaluate surge protective ability as in underground system, when arrestor occurs failure has overhead line. The result shows that lightning arrestor in combined distribution system with power cable protect effectively when failure at arrestor in overhead line. On the other hand, arrestor developed by Cooper Power Systems for underground power cable system, is considered to evaluate surge protective ability in underground distribution system, when arrestor of overhead line has failure. The result shows that lightning arrestor installed in underground cable can effectively protected cables from surge when arrestor of overhead line has failure. And also even though grounding locations are decreased, it is revealed that protective ability is nearly similar.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.501-503
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• 2001

Electric power consumption is highly increasing as the social trend requiring comfortable life, the population in a big city and the industrial development. Therefore it has become to be very important to supply the stable high-quality power. As these trend, the underground power transmission facility is highly increasing in the center of a city. As the proportion to increase facility in tunnel, the fire prevention measures of the underground transmission line become very important.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.612-613
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• 2007

The line impedance is important data that are applied in all analysis fields of electric power system such as power flow, fault current, stability and relay calculation etc. Usually, the impedance can be accurately calculated in case of overhead line. However, in case of power cables or combined transmission lines, the impedance can not be accurately calculated because cable systems have the sheath, grounding wires, and earth resistances. Therefore, if there is a fault in cable system, these terms will severely be caused many errors for calculating impedance. In this paper, the line impedance is measured in a power system of underground cables, and is analyzed by a generalized circuit analysis program, EMTP(Electromagnetic Transient Program), for comparison with the measured value. These analysis results are considered to become foundation of impedance calculation for underground cables.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5123-5127
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• 2011

Research and development for the technology, that is about maintenance and accidents prevention of underground power distribution line, are demanding. The precise detection of leakage point of underground power line is very important, because it is difficult to detect the exact location of a fault in underground power line and to repair faults. When earth electric potential is measured to detect underground electric leakage point after transmitting AC electric pulse wave to underground power line, it must be measured in a specific half period of AC pulse wave because the distribution of the electric earth potential varies with the polarity of the transmitted wave. In this paper we proposed the measurement of half period modulated earth potential as a method to detect a underground leakage point. And We compared the proposed method with other methods. Through experiments we verified that the proposed method can be implemented and operated properly.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.21-27
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• 2015

The goal of this study is the size and distribution of the electromagnetic force generated by the current flowing through the second underground line of 154kV power transmission cables by using electromagnetic finite element analysis. So we interpret how mutually electromagnetic force has an effect on the comparable judgement of Trefoil, Duct and Flat, which shows in a numerical arrangement. 154kV OF 1200SQ Cable 1.281km not only is applicable to modeling for underground transmission cable but also examine the effect of line to line, phase to phase and size and direction of the electromagnetic force preparing for the occurrence of normal state and single-phase earth fault, which are arranged in trefoil, duct and flat formation between sections. As showing how the trajectory, and size distribution of the electromagnetic force translate as the arrangement of the cables when a steady-state current and a fault current flows on the underground cables, I hope that when Underground transmission is designed, this data will be useful information.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.4
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• pp.143-151
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• 2000

Electric power distribution feeders are susceptible to faults caused by a variety of situations such as adverse weather conditions, tree contacts, equipment failure, accidents, etc. Distribution circuit faults result in a number of problems related to the reliability of service and customer power quality. In the distribution line, the permanent interruption of customer service resulting from a blown fuse or a recloser lockout was the only factor which was used to determine service reliability. On underground distribution line, the serving of cables by earth-moving equipment is a prevalent cause of faults and the most cable faults quickly develop into bolted current. we introduce th multi-circuit breaker coordination methods in the Underground Distribution Line.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.10
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• pp.874-884
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• 2013

This paper presents in details channel and noise characteristics over narrow bands below 500kHz based on the field tests over underground low voltage(LV) power lines in residential areas in Korean grid. We show that the channel characteristics of narrowband signals over underground LV power line are decent. We first describe methodology of channel characteristic measurements including channel frequency response, noise, and line impedance, and obtain channel characteristics over the underground LV lines in the residential areas. Also based on the measurement results, we adopt the IEEE P1901.2 standard on the FCC High band, and bring up narrow band power line communication network.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.329-331
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• 2005

This paper proposes a line-to-ground cable fault location method for underground distribution system. The researched cable is composed of core and sheath. And underground cabke system has been analyzed using Distributed Parameter Circuit. The effectiveness of proposed algorithm has been verified through EMTDC simulations.