• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.191-196
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• 2010

The electricity distribution system in Korea is adopting a multi-grounding system. Protection of this distribution system against lightning is performed by installing overhead ground wires over the high voltage wires, and connecting the overhead ground wires to the ground every 200 m. The ground resistance in this system is limited not to exceed $50\Omega$ and overhead ground wire and neutral wire are multiple parallel lines. Although overhead ground wire and neutral wire are installed in different locations on the same pole, this circuit configuration has duplicated functions of providing a return path for unbalanced currents and protecting the distribution system against induced lightning. Therefore, the purpose of this study is to analyze the induced lightning shielding effect according to the neutral wire installation structure of a 22.9kV distribution line in order to present a new 22.9kV distribution line structure model and characteristics. This study calculated induced lightning voltage by performing numerical analysis when an overhead ground wire is present in the multi-grounding type 22.9kV distribution line structure, and calculated the induced lightning shielding effect based on this calculated induced lightning voltage. In addition, this study proposed and analyzed an improved distribution line model allowing the use of both overhead wire and neutral wire to be installed in the current distribution lines. The result of MATLAB simulation using the conditions applied by Yokoyama showed almost no difference between the induced lightning voltage developed in the current line and that developed in the proposed line. This signifies that shielding the induced lightning voltage through overhead wire makes no difference between current and proposed distribution line structures. That is, this study found that the ground resistance of the overhead wire had an effect on the induced lightning voltage, and that the induced lightning shielding effect of overhead wire is small.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1641-1643
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• 1998

In recent the maximum voltage of overhead power transmission lines in Korea was upgraded to 765kV. In general a overhead ground wire is installed for protecting overhead power transmission lines from lightning. For the 765kV line, Composite Overhead Ground Wire with Optic Fiber (OPGW) is applied as a overhead ground wire and have a function of the communication line between substations. In this paper, the construction and properties of OPGW, and its installation methods are discribed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.91-96
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• 2001

This paper describes the effect of an overhead ground wire in Power distribution lines of electric railways due to direct lightning strokes. Using the EMTP, the effects of an overhead ground wire and a s-horn are analyzed quantitatively. Also, the influences of the structure of electric railways and of peak value and time-to-half value of a stroke currents are evaluated. The analysis show that in installation of in overhead ground wire into a existing railway system, the induced voltage in power distribution lines of electric railways in suppressed.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.93-99
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• 2000

Using the EMTP(Electro Magnetic Transient Program) for the analysis of lightning direct voltage on the railway system, the shielding effects of overhead grounding wire on the railway were studied quantitatively. Installation of overhead ground wire and gap-type arrester such as s-horn Provides a 6.6㎸ HV distribution line with good protection effects. Even severe lightning induced voltage were create, 6.6㎸ HV lines can be withstand.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.297-299
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• 2004

In multi-ground distribution system, overhead ground wire and neutral wire are parallel connected to offer the electrical power energy and protect damage of lightning strokes. Therefore a case where the two wires become single wire, the power company can get the benefit such as installation cost saving and line fault protection by simplify of distribution line. In this paper we describe the result of impulse test in both system ; one is the present power system the other is unified power system parallel connected overhead ground wire and neutral wire. As a result of this impulse test, the present power system get lower impulse voltage than the unified power system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2135-2142
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• 2010

This paper studies the validity about a joint operation of neutral wire and overhead grounding wire in combined distribution systems. The overhead grounding wire and neutral wire are currently installed separately and grounded by common. However there is no any ineffectiveness or electrical problem in case of the proposed system, such system can be operated at real distribution system. Therefore this paper describes the suitability of a joint operation through lightning surge analysis on combined distribution systems. Lightning surge analysis is carried out by EMTP/ATPDraw to obtain the overvoltage of overhead line and underground cable in various conditions such as locations and current types of lightning stroke. Overvoltage gained by the analysis show that the insulation strength of the joint operation case is not stable compare with the current operation case.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.85-89
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• 2010

During a ground fault the maximum fault current and neutral to ground voltage will appear at the pole nearest to the fault. Distribution lines are consisted of three phase conductors, an overhead ground wire and a multi-grounded neutral line. In this paper phase to neutral faults were staged at the specified concrete pole along the distribution line and measured the ground fault current distribution in the ground fault current, three poles nearest to the fault point, overhead ground wire and neutral line. A effect by grounding resistance of poles of ground fault current in the 22.9[kV] multi-ground distribution system. by field tests.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.3
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• pp.331-337
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• 2014

The Korean distribution system consists of overhead ground wire (OHGW), phase conductors and neutral wire. Especially, OHGW is installed over the phase conductors to protect distribution system from the lightning surge. The flashover rate and the magnitude of lightning overvoltage on distribution system can be affected by grounding condition of OHGW such as grounding resistance and grounding interval. In this paper, we conduct an analysis of lightning overvoltage and flashover rate according to the grounding condition of OHGW. The distribution system and lightning surge are modeled by using ElectroMagnetic Transient Program (EMTP). Also, the Monte Carlo method is applied to consider random characteristics of lightning, and the flashover rate is calculated based on IEEE std. 1410. The simulations are performed by changing the grounding resistance and interval of OHGW and the simulation results are analyzed.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.468-470
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• 1999

Using the EMTP(Electro Magnetic Transient Program) for the analysis of lightning direct voltage on the railway system, the shielding effects of overhead grounding wire on the railway were studied quantitatively. Installation of overhead ground wire and sap-type arrester such as s-horn provides a 6.6kV HV distribution line with goof protection effects. Even severe lightning induced voltage were create, 6.6kV HV lines can be withstand.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.7
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• pp.37-44
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• 2013

Phase to ground faults are possibly one of the maximum number of faults in power distribution system. During a ground fault the maximum fault current and neutral to ground voltage will appear at the pole nearest to the fault. Distribution lines are consisted of three phase conductors, an overhead ground wire and a multigrounded neutral line. In this paper phase to neutral faults were staged at the specified concrete pole along the distribution line and measured the ground fault current distribution in the ground fault current, three poles nearest to the fault point, overhead ground wire and neutral line. A simplified equivalent circuit model for the distribution system under case study calculated by using MATLAB gives results very close to the ground fault current distribution yielded by field tests.