• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1688-1690
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• 2002

The unpredictable threat of lightning surge is ever increasing in today's low-voltage power supplies. Thus Surge protection devices for AC mains are more widely used. The false-tripping of the earth leakage breaker (ELB) can be caused by the installation of surge protection devices with MOV. In order to examine the cause of malfunction, the malfunction characteristics of ELBs applied by lightning surge were investigated experimentally. As a result, all of them brought about malfunctions under 7 kV of the impulse voltage. The suitable position of MOV and use of zener diode were suggested to eliminate the problems.

• Fire Science and Engineering
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• v.25 no.1
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• pp.50-56
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• 2011

In recently years, occurrences of lightning return strokes have been increased by global worming effect and intensity of lightning impulse voltage and current accompanied by lightning discharges has being strengthening. In Korea, 560 thousand lightning discharges happened in 200S. According to the increasing frequencies of lightning, human deaths and damages to the structure have been increased steadily. Electric fire caused by lightning return strokes due to the breakdown between power line and ground line from the ground potential rise on a process of the lightning impulse current through to the ground. The damages of lightning were occurring at same time in the neighboring areas of the lightning point. In order to protect from the lightning stroke, we made a suggestion to use protection devices and equipotential bonding at the dangerous areas. The analysis results of electric fires caused by lightning would be utilized to investigate and to find accurate fire cause in the fire scenes.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.81-86
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• 2013

An electric potential rise of the grounding electrode developed by the lightning stroke currents should be calculated for the purpose of effective protection of electrical and electronic equipment. In this paper, the electromagnetic model was applied to calculate the harmonic impedance of grounding electrode. Also the empirical equation related to the permittivity and resistivity of soil was used. The lightning current waveforms, which are expressed by the Heidler's equation, were used in order to calculate accurately transient electric potential rises. The transient voltage was obtained by using the simulated harmonic impedance and the lightning current in frequency domain. Finally, the transient voltages of horizontal grounding electrode(10m) under lightning stroke currents were calculated by IFFT(Inverse Fast Fourier Transform).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.616-619
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• 2004

Lightning surge damages of low voltage equipments in building are increasing due to increase in electrical and communication networks in the information-oriented society. And electronic equipments contained electrical circuits with semiconductor are very weak against lightning surge. The surge protective devices for electronic circuit in electronic equipments and AC power lines are becoming more widely. To achieve effective method of surge protection, there are needs for correlation between lightning surge protective effect of electronic equipment and installation method of surge protective device. This paper describes as a result of experiments for correlation between lightning surge protective effect and installation method of surge protective device.

• Proceedings of the KIEE Conference
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• 2004.11d
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• pp.40-42
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• 2004

Electronic equipments made from electrical circuits with small-sized semiconductor are very weak against lightning surge. So, electronic equipments is protected by SPD(surge protective devices) such as Zno varistor. The SPD protect electronic circuit in electronic equipments and AC power lines from the lightning surge. Therefore to achieve effective method of surge protection, there are needs for correlation between lightning surge protective effect and installation method of surge protective device. Therefore this paper describes as a result of experiments for correlation between lightning surge protective effect and installation method of surge protective device.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.6
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• pp.279-285
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• 2005

The lightning causes the damage of power system equipments as well as large power failure. Therefore, the insulation design should be established not only to decrease the damage of the facilities itself but also to increase the reliability of electric power system. This paper describes the useful way applying underbuilt ground wire and guy wire in transmission tower that safely protect the substation equipments. One or more shield wires under the phase conductor will not intercept lightning stroke, but they may improve reduce lightning voltages almost as effectively as if they were above the phase conductors. And the guy wires will mitigate the tower surge response. These would not only reduce backflashover possibility but also minimize crest and duration of surges entering the substation. EMTP is used to analyze the efficiency of the proposed methods.

• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.171-176
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• 2005

The effects of surge arresters for the protection of transmission systems against direct lightning strokes have already been reviewed by many researchers. However, their studies have not encompassed underground cable systems. Therefore, in this paper we investigate the 22.9kV combined distribution systems that have arresters and ground wires. In addition, we analyze the overvoltages on underground distribution cable sections when direct lightning strokes contact the overhead ground wire using EMTP. Finally, we discuss the effect of lightning strokes according to the change of cable length and installation of arresters. This study provides insulation coordination methods for reasonable system design in 22.9kV underground distribution cable systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1861-1868
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• 2009

A ground electrode subjected to lightning surge current shows the transient impedance behaviors. The ground electrode for protection against lightning should be evaluated in view of the transient grounding impedance and conventional grounding impedance, not ground resistance. The transient impedance characteristics of ground electrodes are influenced by the shape of ground electrode and the soil characteristics, as well as the waveform of lightning surge current. In order to propose a simulation method of analyzing the transient impedance characteristics of the grounding system in practical use, this paper suggests a theoretical analysis method of distributed parameter circuit model to simulate the transient impedance characteristics of counterpoise subjected to lightning surge current. EMTP and Matlab programs were employed to compute the transient grounding impedances of three counterpoises with different lengths. As a consequence, the simulated results using the proposed distributed parameter circuit model are in good agreement with the measured results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.96-101
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• 2012

A surge protection device of the metal oxide varistor(MOV) has been commonly used for preventing electrical damage in many electronic equipments. The MOV has a property that leakage current is increased and might be permanently damaged when it is exposed continuously to the electrical stresses such as lightening surges. In this paper, we propose a novel surge protection circuit adopting a silicon controlled rectifier(SCR) in the traditional protection circuits using the MOV device simultaneously. When lightning surges are injected to the proposed circuit, the MOV lets the surge pulses bypassing through the ground at first up to the level that SCR begins to operate. Above the threshold level of turning on the SCR, the SCR operates bypasses large surge currents to the ground. Proposed circuit was verified with a leakage current experiment and PSpice circuit simulations under the repeated surge injection environment.

• International journal of advanced smart convergence
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• v.2 no.1
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• pp.27-29
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• 2013

This paper discusses comparative analysis of the effects of surge protection devices (SPD) upon the power line communication channels. The quality of the data transmission channel is measured based on the data rate for the various channel parameters which include channel length and application method of the lightning protection device. The performance measurements are also carried out for various lengths of the communication channel. Experiment results show that specific combination of SPDs applied in the network causes severe degradation of the channel quality which is associated with the combination of grade levels and channel lengths.