• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2235-2237
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• 2005

This paper presents the transient impedance behaviors of grounding systems to lightning impulse current. The potential rise and effective impulse ground impedance of the test grounding electrodes were measured as a function of the rise time of impulse currents and lengths of down conductor. The transient ground impedances strongly depend on the configuration and size of grounding electrodes, the impulse current shapes and lengths of down conductor, and the inductance of reduce of grounding electrode inductance is an important factor to improve the transient ground impedance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.6
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• pp.1103-1108
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• 2010

A grounding electrode has the transient grounding impedance characteristics against lightning surges. So the performance of grounding electrodes should be evaluated as a grounding impedance as well as the ground resistance. The frequency-dependent grounding impedance is varied with the shape and size of grounding electrode and is divided into both inductive and capacitive behaviors. This paper presents a theoretical analysis for the grounding impedance determined by the size of grounding electrode using the distributed parameter circuit model. EMTP and Matlab programs were used in calculating the frequency-dependent grounding impedances of vertical grounding electrodes. It was found that the frequency-dependent grounding characteristics of vertical grounding electrodes are characterized by the distributed parameters which are changed in the dimension of grounding electrodes.

• 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 KIEE Conference
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• 1997.11a
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• pp.361-363
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• 1997

Electronic devices are very weak against lightning surges injected from grounding systems and can be damaged. The malfunction and damage of electronic circuits bring about several disadvantages such as low operation performances, a lot of economical losses, and etc. In order to obtain the effective protection measure of electronic devices from overvoltages and lightning surges, the analysis of the transient grounding impedances is very important. The aim of this work is to evaluate the behaviors of transient grounding impedances under impulse currents and to investigate the effect of grounding lead wire. Z-t, Z-i and V-i curves of transient grounding impedance under impulse current waveforms have been measured and analyzed.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.197-203
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• 2014

When the lightning current is injected to the ground system of information and communication facilities, analysis of the transient potential rise in the ground system is one of main factors to effectively design the ground system. The performance of grounding systems is normally estimated with the grounding impedance and the transient potential rise which represents the electrical characteristics of the grounding system. The method for calculating the grounding impedance depending on the injection point of the lightning current was proposed. The delta-gap source model was proposed to calculate the grounding impedance in the case that the lightning current is injected to the center of the horizontal ground electrode. A new program which is possible to apply the frequency-dependent soil parameters using the Debye model was developed, because a commercial program for analyzing the performance of the grounding system can not apply to the frequency-dependent soil parameters. The experiment was carried out to confirm the availability of the simulation results with the same condition. Finally, the transient potential rises of a horizontal ground electrode depending on the lightning current waveforms were analyzed by using the results of the grounding impedance which is associated with the frequency-dependent soil parameters.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1589-1591
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• 1998

This paper presents experimental results of transient impedance characteristics investigated on the site of a large-scale grounding system using impulse current. The ground potential rise was measured while injecting an impulse current and the transient impedance was determined. As a results, the transient impedance was significantly greater than the stationary grounding resistance due to high inductance of ground conductors and leads.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.47-50
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• 2009

When the lightning currents flow through the ground electrode, the grounding system should be evaluated by the grounding impedance rather than the ground resistance because a grounding system shows the transient impedance characteristic by the inductance of the ground electrode and the capacitance of the soil. The ratio of the peak values of electric potential and currents is the conventional impedance that shows the transient characteristic about impulse currents of the grounding system in a roundabout way. The grounding system having low conventional impedance is a fine grounding system with low electric potential when the lightning currents flow. In this paper the conventional impedance of the counterpoise is calculated by using the distributed parameter circuit model and embodied the distributed parameter circuit model by using the EMTP program The adequacy of the distributed parameter model is examined by comparing the simulated and the measured results. The conventional impedance of the counterpoise is analyzed for first short stroke and subsequent short stroke currents.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.6 no.5
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• pp.45-49
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• 1992

The transient characteristics of grounding systems are very important in the insulation design of electrical installations and depend on the shape and size of electrodes, soil resistivity and the magnitude and wave of the injection current. This paper establishes an algorithm to compute the surge impedance of two or more grounding systems using the Laplace Transformation technique and deals with the analysis of the transient characteristics on grounding systems.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.6
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• pp.289-297
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• 2000

This paper presents a comparison on the resistance and characteristics of transient response of grounding systems under surge currents using frequency domain electromagnetic field analysis software package and field test. Analysis is done by computer model, based on electromagnetic field theory approach, that accurately takes into account frequency dependent characteristics of the system. The transient performance of three grounding systems is analyzed by comparison of frequency dependent impedance and the maximal transient GPR. A double exponential lighting surge current is injected at one corner of the grounding systems. The transient GPRs a rod grounding systems are higher than mesh or electrolytic grounding systems. Af field test, the results of resistance measurement and time-variant of ground resistance slightly reduce electorlytic grounding systems less than rod and mesh grounding systems.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1418_1419
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• 2009

This paper presents the transient impedance when high current impulse up to 5 kA is applied to a scaled grounding grid in test field. For a realistic analysis of transient impedance on the high current impulse in the ground systems, grounding electrode installed outdoors and impulse current generator was used. The results were discussed based on its voltage and current trace, impulse impedance and V-I curve.