• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.199-201
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• 2007

This paper presents the installation of measuring system for the transient behaviors of grounding system impedances using portable impulse current generator. The measuring system is controller, with controller, power supply, impulse current generator and data aquisition system. In the evaluation of the impulse response in a ground electrode, the step response is calculated based on the ratio of the voltage and current observed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1822-1828
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• 2008

This paper presents design parameter calculation methodology and its realization to construction for the 10/350${\mu}s$ lightning impulse current generator(ICG) modelled as double exponential function waveform with characteristic parameters ${\alpha},{\beta}$. Matlab internal function, "fzero" was applied to find ${\lambda}={\alpha}/{\beta}$ which is solution of nonlinear equation linearly related with two wave parameter $T_1$ and $T_2$. The calculation results for 10/350${\mu}s$ lightning impulse current show very good accuracy with error less 0.03%. Two type of 10/350${\mu}s$ ICGs based on the calculated design circuit parameters were fabricated by considering the load variation. One is applicable to the MOV based Surge protective device(SPD) for less 15 kA and the other is to test small resistive devices such as spark gap arrester and bonding device with maximum current capability 30 kA. The tested waveforms show error within 10% in comparison with the designed estimation and the waveform tolerance recommended in the IEC 61643-1 and IEC 60060-1.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2255-2262
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• 2008

This paper presents a design parameter calculation methodology and its realization to construction for the damped oscillatory impulse current generator(ICG) modelled as damping factor $\alpha$. Matlab internal functions, "fzero" and "polyfit" are applied to find a which are solutions of second order nonlinear equation related with three wave parameters $T_{1},T_{2}$ and $I_{os}$. The calculation results for standard impulse current waveforms such as 4/10${\mu}s$, 8/20${\mu}s$ and 30/80${\mu}s$ show very good accuracy and this results make it possible to extend to generalization in the design of damped oscillatory lCG with any capacitor. 8/20${\mu}s$ ICG based on the calculated design circuit parameters is fabricated in consideration of the nonlinear load(MOV) variation. Comparisons of the tested waveforms with the designed estimation show error within 10% for the waveform tolerance recommended in IEC 60060-1 and IEEE std. C62.45.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.907-909
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• 1998

This paper describes the effect of impulse current on degradation of ZnO blocks. In this study, an impulse current generator which can produce 8/20 [${\mu}s$], 3 [kA] and 4/10 [${\mu}s$], 5 [kA] waveform is designed and fabricated to simulate the lightning impulse current. The residual voltage, reference voltage, and leakage current flowing to the ZnO blocks are observed. The experimental results show that the leakage current increases continuously with the number of applied impulse current, but no significant changes in residual voltage and in operating voltage are observed until the ZnO block is destroyed. Also, it is confirmed that the main factor on degradation of ZnO blocks is rather the total energy applied to ZnO blocks than the peak value of the impulse current.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.93-100
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• 2011

This paper presents a technical study for the first short stroke lightning current generator using a crowbar device. The so-called crowbar-technology is most common to make 10/350[${\mu}s$] impulse currents with high amplitude, and the lightning current generator with crowbar device has an economic advantage than the nominal RLC current generator. But both the operating efficiency and the operating reliability of crowbar spark gap are very important to design the current generator. So, the peaking circuit which consists of small capacitors and a spark gap is applied. And the multi-step coil for controlling the circuit constant at the different test conditions is used. The presented test facility is designed to perform impulse tests with amplitudes up to 50[kA] of 10/350[${\mu}s$].

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.7
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• pp.550-555
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• 1999

This paper deals with the effect of lightning impulse current on electrical characteristics of ZnO blocks used in distribution lightning arrester. The electrical characteristics of ZnO blocks are degraded by overtime impulse current, and the degraded ZnO block is brought to a thermal runaway and finally destroyed. It is therefore important to estimate the change of electrical characteristics of ZnO blocks. In this study, an impulse current generator which can produce 8/20$[\mus]$, 3[㎄] and 4/10$[\mus]$, 5[㎄] waveform is designed and fabricated to simulate the lightning impulse current of power systems. Total energy applied to the ZnO blocks at each time is 739[J] in 8/20$[\mus]$, and 523[J] in 4/10$[\mus]$, impulse current, respectively. From the experimental results, the 3rd harmonic of the leakage current increases continuously with the number of applied impulse current, but no significant changes in residual voltage and in reference voltage are observed until the ZnO block is destroyed. Also, it is confirmed that the main factor on degradation of ZnO blocks is rather the total energy applied to ZnO blocks than the peak value of the impulse current.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.6 s.336
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• pp.61-66
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• 2005

In this paper, we implemented a impulse generator, the one of the part in UWB(Ultra Wide Band) system using step recovery diode(SRD) and gain-switced semiconductor laser. The impulse generator was consisted of four stages; The first stage used SRD to generate the first impulse for gain switching. The second stage controled current for the suitable gain switching condition. The third was the second impulse generator to generate gaussian pulse. For gain switching, the first impulse was applied to semiconductor laser. In the last stage the gain switched impulse was converted into mono-gaussian pulse. The measured mono-gaussian pulse was 360 psec pulse-width and $-70mV \~ +50mV$ amplitude in time domain. In frequency domain its magnitude and bandwidth was, respectively, -41dBm and 3.6GHz. Accordingly, the impulse generator that we suggested was suitable for UWB 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.5
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• pp.79-84
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• 2012

As the huge economical loss and function paralysis of information technology-based systems can be caused by the misoperation of residual current devices(RCDs) due to surge voltages and currents, RCDs shall not operate by surge currents. In this paper, in order to evaluate the reliability of residual current operated circuit-breakers with integral overcurrent protection for household and similar uses((RCBOs) stressed by surges, the unintended trip characteristics of RCBOs under surge currents were experimentally investigated using the combination wave generator. Seven different types of single-phase RCBOs being present on the domestic market were investigated according to KS C IEC 61009-1 standard. As a result, all kinds of specimens were satisfied the requirements for 0.5 [${\mu}s$]/100[kHz] ring wave impulse currents. Most of specimens stressed by the 8/20[${\mu}s$] impulse current tripped at least one or more, and some of them were broken down during consecutive tests. It was found that only one type of specimens meets the L-N mode immunity to the combination wave of 1.2/50[${\mu}s$] impulse voltage and 8/20[${\mu}s$] impulse current.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.12
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• pp.685-690
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• 2000

Multiple-lightning impulse currents are a general feature of the lightning ground f=flash. It is therefore necessary for lightning arresters used in power systems to be estimated by applying not only a single-lightning impulse current but also a multiple-lightning impulse currents. This paper presents the effects of multiple-lightning impulse currents on deterioration of ZnO arrester blocks. The multiple-lightning impulse generator which can produce quadruple 8/20$[\mus]$ 5[kA] with separation time of 30~120[ms] is designed and fabricated. The total energy applied to the arrester block at each impulse is about 1,200[J]. In experiment, various parameters such as leakage current component, reference voltage, and temperature are measured with the number of applied impulse current. Also, micro-structure changes of the ZnO blocks after applying the single and the multiple-lightning impulse currents of 200 times are compared. The experimental results indicate that the types of arrester blocks are more vulnerable to deterioration or damage by multiple-lightning impulse currents.