• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.305-308
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• 2008

This paper presents characteristics of soil ionization when high currents such as lightning and switching surge currents are injected into a grounding rod. Soil ionization phenomena are investigated by using both voltage and current signals recorded by oscilloscope. As a result, a critical electric field intensity($E_C$) for ionization is decreased with reduction of grain size. The pre-ionization resistance($R_1$) and post-ionization resistance($R_2$) at the sand with fine grain size are getting lower with increasing current magnitude. Finally, the time to ionization($t_1$) and ionization current peak($t_2$) of fine grain size are significantly shorter than those of medium grain size.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.575-580
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• 2004

The latest equipment automatic Intelligence of digital base done large size equipment appear in succession. That run by voltage electric current(mA, mV, ${\mu}A,\;{\mu}V$) that outline is microscopic of action of accuracy large size equipment of this digital base is bulk. Have received influence that is great in river electric field by installment that use computer. Most of domestic working voltage from service entrance extra-high voltage and working voltage of commercial frequency 60Hz working voltage 220V that use our country outside 1 country in interior of 22.900V for semiconductor use computer use digital installment of appliance as well as various smalls of digital base, middle, large size that safety is these fine voltage electric current that is not enough direct admonition hundred vast damage give can. Also, already act in surge circle and impulse transient phenomena such as several thousands, myriads, strong bit error more than billions time to digital fine electronic circuit by mistake use of using electric facility system of system electric power.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2106-2108
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• 2003

단상 또는 3상의 AC 전원의 전류나 전압 또는 전력을 계측하기 위해 Analog Signal들을 Digital Signal로 변환하여 특정 Algorithm의 연산을 수행하여 결과를 얻는 과정을 Microprocessor를 이용하여 처리하는 방법은 산업현장이나 연구개발에서 흔히 사용하는 방법이다. 본 논문에서는 Microprocessor를 이용하여 보편화된 3가지의 계측 Algorithm인 DFT, True RMS, Summation Algorithm을 사용하여 동일 System에 3상 AC의 전류 부하를 일정 범위에서 가변 하여 인가시키면서 계측 값을 사용하여 Algorithm의 계측 결과의 오차율과 연산에 소요되는 시간과 외부 잡음인 Surge, Impulse, 정전기, 방파, 고조파에 대한 System의 처리 효율을 연구 하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.79-86
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• 2008

This paper presents the experimental results of impulse breakdown characteristics in $SF_6/N_2$ gas mixtures under a highly non-uniform electric field with a change in temperature. The test temperature ranges from -25[$^{\circ}C$] to 25[$^{\circ}C$]. The processes of impulse preliminary breakdown developments were analyzed by the measurements of current pulse and luminous signals. As a result, the temperature dependance of breakdown voltage for the negative polarity was much stronger than that for the positive polarity. When increasing the temperature, The leader stepping time for the negative polarity was shown to be longer than that for the positive polarity. The results presented in this paper can be used as a useful information in designing the gas insulation lines with prominent ability for lightning surge.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.486-489
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• 1999

This paper deals with the design rule and performance results of the transient voltage blocking devices (TBD) for low-voltage mains on shipboard. The proposed TBD consists of metal oxide varistors (MOV) and L-C filter to improve noise-elimination performance. Three kinds of TBDs are fabricated and tested by using a combination surge generator which can produce the standard impulse current of 8/20${\mu}$s 2.1kA. As a reults, the proposed TBD with series L-C filter has more excellent transient blocking and noise reduction performance than the conventional TBDs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.8
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• pp.64-70
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• 2007

The electrical accident results from an insulation blackdown by over-voltage, an overheating by the excess of allowable current, a deterioration performance by the passage of time, and so on. This paper discusses how to improve the power control system of PCB in water purifier. The protecting device of present power supply control system in water purifier is composed of the varistor device which acts only for impulse-type surges. So the present system can not be protected others except the surge of impulse-type. The newly-suggested power control system in this paper is designed to protect the system by disconnecting power supply through SSR(Solid State Relay) if the value of input voltage is exceeded the setting value.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.133-143
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• 2001

This paper describes the correlation of the transient impedance and its parameters with the stationary resistance of a grounding system to a square pulse current and a lightning impulse current. In the experiment, the grounding system consists of a single grounding rod$(\Psi10[mm], 1[m])$and/or a triple-grounding rods of equilateral triangles with 5[m] spacing for operation. To analyze the transient impedance characteristics of the grounding system, a pulse generator which can produce square wave of a 30[ns] rise-time and a $20[\mus] $pulse duration is designed and fabricated. The injected content in the grounding system and the developed potential were recorded, and the time variation of the transient impedance were calculated as the ratio of the potential rising to the injected current at each time. The transient impedance and the effective surge impedance Z3 which defines economic protection level in power system were quite higher than the stationary resistance. The grounding impedance is decreased by the application of the triple-rods grounding system, and its effect is decreased as the frequency of the current is increased due to the inductance of the grounding leads.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2503-2508
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• 2014

This study is about the selection and noise test of electronic sensor which is preceded by electric Operating Cell(EOC) development using electronic sensor technology to solve the structural weakness of Mechanism Operated Cell(MOC) in VCB, and has a final target in product development minimizing contact malfunction of the chattering or rebounce states caused by existing MOC. In this test results, when opening and closing VCB, rising velocity of surge voltage in opening time was measured 4.2 times faster than closing time and noise decibel value was measured respectively 120dB and 110dB. When supplying 60kV power frequency overvoltage, we found that sensor output graph in VCB opening and closing times operated stably without distortion. When supplying 150kV $1.2{\times}50{\mu}s$ impulse frequency voltage, we found that voltage graph of output contact in sensor opening and closing sides maintained a normal condition without distortion, and when supplying 2500A current, we found that tested result of electric field noise operated stably without distortion.