• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.978-979
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• 2006

Recently, Peoples are exposed the ELF(Extremely Low Frequency) magnetic fields in the vicinity of underground transmission lines, and there are the generally accepted opinion that the magnetic fields affect the human body and there are possibility of the disease. Also in relation to this problem, technical solution methods and research are advanced for reducing the magnetic fields. In this paper, to practically understand the magnetic fields underground transmission lines, We analyze the electromagnetic field distribution in the underground transmission lines by means of FEM(Finite Element Methods) and present that improvement of the effective shielding methods by applying cable arrangements and shielding materials, eddy current problem to the underground transmission lines by means of the numerical analysis Tool.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1815-1817
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• 2003

Since the first underground transmission line in Korea was installed in 1974, the two types of underground transmission power cables, oil-filled and XLPE, have been applied for underground transmission lines. As the manufacturing technologies of XLPE cable have been improved and the simplicity of installation and maintenance has been focused on, the installations of XLPE cables have been largely increased since the mid 1990's. For the first time, in Korea, the 345kV XLPE cable was installed at Pyungtaek thermal power plant in 2003, February. So, this paper introduces the project profile, the design of cable and its accessory, the cable system design, installation and site test.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.10
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• pp.602-609
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• 2003

This paper describes the fault location calculation using neuro-fuzzy systems in combined transmission lines with underground power cables. Neuro-fuzzy systems used in this paper are composed of two parts for fault section and fault location. First, neuro-fuzzy system discriminates the fault section between overhead and underground with normalized detail coefficient obtained by wavelet transform. Normalized detail coefficients of voltage and current in half cycle information are used for the inputs of neuro-fuzzy system. As the result of neuro-fuzzy system for fault section, impedance of selected fault section is calculated and it is used as the inputs of the neuro-fuzzy systems for fault location. Neuro-fuzzy systems for fault location also consist of two parts. One calculates the fault location of overhead, and the other does for underground. Fault section is completely classified and neuro-fuzzy system for fault location calculates the distance from the relaying point. Neuro-fuzzy systems proposed in this paper shows the excellent results of fault section and fault location.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.4
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• pp.193-200
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• 2003

The use of underground transmission tables has continuously increased in densely inhabited urban and suburban area. Due to a increasing demand of underground cables, two or more circuits are installed in parallel for several kilometers. It, however, has not been realized that the sheath circulating current is generated in the system where a large number of cables are laid in the same route. In this paper, Author studied diversely the sheath circulating current on underground cables depending on the various length rate, the phase arrangement, and the grounding resistance of the sheath in the cross-bonded section. It was clear that very large circulating current is generated in cable systems due to unbalanced length rate and phase arrangement in the cross-bonded section.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.558-560
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• 2003

The effects of surge arresters for protection of transmission systems against direct lightning strokes have already been investigated using the digital simulation program EMTP. Distribution lines are spanned on a much large area as compared to transmission lines, and therefore, are more often susceptible to lightning strokes. This paper analyzes the overvoltages on underground cable system against direct lightning strokes to the overhead ground wire using the digital simulation. The effects of lightning protection methods, such as lowering the grounding resistance and installing the surge arrester, for preventing overvoltages on underground cable system caused by direct lightning strokes to the overhead ground wire is investigated. Several schemes have been proposed to protect underground cables. This paper summarizes the main results of a study aimed at analysis of lightning overvoltages in variety underground feeders protected by metal-oxide arresters. This study will provide insulation coordination methods for reasonable system design in 22.9kV underground cable system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2113-2118
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• 2016

The precise detection of electric leakage point of underground power cable is very important to reduce cost and time of maintenance and prevent electric shock accident through expedite repair of electric leakage point. This paper proposes a electric leakage point detection system underground power cable using of half-period modulated transmission waveform and earth electric potential measurement. The developed system is composed of transmitter to generate the wanted pulse waveform, receiver to measure and display earth electric potential by the transmitted pulse in electric leakage point and PC Software program to display of GPS coordinate on detection cable line. The performance of the electric leakage point detection system was tested in the constructed underground cable leakage detection test bed. The test results on signal generation voltage precision of signal transmitter, mean detection earth voltage, mean detection leakage current and electric leakage point detection error showed the developed system can be used in electric leakage point detection underground power cable.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.15-17
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• 2005

The protection of underground cables against transient overvoltages resulting from lightning and other causes is important in cable-line which is connected with overhead line and underground cable. This paper investigates the failure of SVL(Sheath Voltage Limiter) and presents the application of protection methods for single point bonding on underground transmission cable system. EMTP(Electromagnetic Transient Program) is used in order to study the overvoltages and modeling of components of the system such as, underground cables, SVLs and towers.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.2
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• pp.69-77
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• 2004

Now, there are some problems to manage underground facilities in domestic. Specially, in the case of KEPCO(Korea Electric Power Corporation), it is so difficult to manage electronic line more stably and detailedly because the geographic information and attribute information being built is not easy to be updated in the field. KEPCO officials who are accompanying management and supervision in earthwork do not have sufficient knowledge and information about GIS but they grasp the information of geography and property which coincide with the field. Therefore they have to refer their business analysis contents sufficiently for more efficient lines management in the KEPCO, but it is problem that the existing information of electronic lines management system is not. In this study, we constructed power transmission and power distribution underground facility management system for the user to manage and maintain underground facilities more easily and safely using the information of geography and property about power transmission and power distribution underground facility which have been built by KEPCO.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.61-65
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• 2002

It becomes difficult and high in cost to construct new ducts and/or tunnels for power cables in metropolitan areas. This paper presents possible applications of an HTS superconducting power cables for transmitting electric power in metropolitan areas. Reflected were its important distinction such as compactness for installation in underground ducts and considerably high efficiency compared with present underground cables. In this paper, system modeling, transmission capacity and voltage class of compact HTS cables which should be applied to existing ducts were reviewed. Based on this, the following items on urban transmission system are examined. (1) A method of constructing a model system to introduce high temperature superconducting cables to metropolitan areas is presented. (2)The maximum outer diameter of HTS cables to be accommodated in exiting ducts is calculated based on the design standards for current cable ducts. (3)The voltage level that can be accommodated by existing ducts is examined.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1626-1628
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• 1998

In reccent years the large capacity underground power transmission systems have been required gradually with the increasing demand of electric power, the increasing electric power system and the environmental limitations of an overhead transmission line in the city. But it is difficult to get the space for the underground power transmission lines because of complicated distributions of underground public facilities. But as the superconducting power cables have the large power transmission capacity, the high power transmission density, and low loss characteristics in comparison with a conventional cable, the necessity for their development are increasing. In this paper, the results of the conceptual design of HTS power cable is described.