• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1713-1714
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• 2006

This paper aims to analyze the overvoltage in underground distribution systems when lightning surge strikes to overhead line. The model is established by EMTP/ATPDraw for actual distribution systems. Simulation is carried out considering variation of parameters such as length and lightning current.

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.357-361
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• 2006

This paper dealt with the performance evaluation and the diagnostic techniques of lightning arresters for DC electric traction vehicle. Field Measurements on the protective operation of lightning arresters against surge currents were carried out on running vehicles to acquire the data necessary for the diagnosis. The frequency and the magnitude of surge events were analyzed. Surge currents of $1\sim3$ times were recorded in one running service route and their magnitudes were ranges of $150A\sim2kA$. Also, an acceleration experiment on a lightning arrester by the standard lightning impulse current of 8/20 us and 5 kA was performed to know the aging characteristics. After the surge current application of 3,000 times, the reference voltage decreased by 4.5 %, and the leakage current was below 10 uA at the continuous operating voltage and about 50 uA at the rated voltage. From the experimental results, we propose a decision level of leakage current for the arrester used in this paper and designed an arrester tester which analyzes arrester condition by the magnitude of leakage current.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1305-1306
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• 2008

In this work, in order to investigate the effect of lightning impulse currents on ZnO surge arrester. and the deterioration characteristics of ZnO surge arrester, 8/20 [${\mu}s$], 2.5 [kA] impulse currents were applied to the ZnO surge arrester under test. The leakage currents of ZnO surge arrester were measured and ZnO element was analyzed by X-ray photoelectron spectroscopy. As a result, the resistive leakage current of ZnO surge arrester was increased with the injection number of lightning impulse currents.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1888-1890
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• 2000

This paper describes the analysis results for the protection of lightning surge at 154 kV substation. We found that the surge arrester is needed at the inlet structure. The maximum overvoltage is about 1,500 kV at the circuit breaker without the surge arrester at the inlet structure. This value can be lower than 600 kV by installing the surge arrestor at the inlet structure. In addition to the incoming surge from transmission line, the shield wire should be considered to prevent the shielding failure by the direct lightning stroke.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.578-579
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• 2011

This paper describes the analysis of induced lightning surge phenomena at underground power cables under construction when the lightning surge strikes at phase conductor of grounding wire of overhead line in service. Therefore, This paper proposes the optimal protection methods establishment against lightning surge induced from operating transmission.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.167-170
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• 1997

The arc fusion faults in the distribution lines are occurred by lightning surge, stress corrosion and substance touching. Arc fusion fault by lightning surge is one of the most frequent occurrence. In this report, we studied the mechanisms of the Arc fusion faults. Also, we analyzed the reduction effects for surge voltage of lightning protective equipments.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1877-1879
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• 2000

This paper deals with the change of the micro-structure of ZnO associated with lightning surge current and ageing test. In this work, a surge current generator which can produce 8/20 [${\mu}s$], 6 [kA] impulse current is designed and fabricated to simulate the lightning impulse current. The residual voltage and leakage current flowing to ZnO blocks are observed. Also a compensation circuit was used in resistive current measurement. The micro-structures of ZnO arrester block were significantly changed by lightning surge current and accelerated temperature ageing test.

• 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.

• 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.

• 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.