• JOURNAL OF ELECTRICAL WORLD
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• no.8 s.104
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• pp.88-95
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• 1985

접지란 한마디로 말하면 여러 가지의 설비를 대지와 전기적으로 연결시키는 것이다. 영국에서 Earthing, 미국에서는 Granding이라고 한다. 우리나라에서는 일반적으로 어스라고 하며 역할에 따라 프레임어스와 시그널어스의 2종류로 대별된다. 이들의 성격은 상당한 차이가 있다. 강전용의 접지는 보안용이며 보통은 그 접지계에 전류가 흐르지 않는다. 이에 대하여 약전용의 접지는 회로기능용이며 상대 전류가 흐른다. 이 명확한 차이를 인식해야 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.6
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• pp.100-108
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• 2008

The transient ground impedance depending on configuration, size, and material of grounding electrodes as well as the shapes of impulse currents, has a significant affect on the performance of the grounding system. This paper presents experimental results in regard to the analysis method of transient ground impedance using the lightning impulse and variable frequency currents. Also a new estimation method to replace the effective surge impedance for transient ground impedance was proposed. The ground electrodes used in this experiment are virtual ground electrodes including both resistance and inductance components, carbon ground electrode with 1[m] length, copper electrode with 9[m] length and counterpoise with 40[m] length. Ground impedances using the proposed method were measured respectively. Comparing with the ground impedance using variable frequency current the conventional ground impedance($Z_1$) calculated from the peak values of impulse voltage and impulse current is observed more correct method for evaluating the performance of ground electrode than the effective surge impedance.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1568-1569
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• 2011

최근 기후변화로 인해 낙뢰의 발생빈도가 크게 증가하고 있으며 이에 따라 피뢰시스템의 중요성이 부각되고 있다. 피뢰시스템의 원활한 기능을 수행하기 위해 접지시스템의 성능이 보장되어야 하며, 접지전극은 뇌격전류를 안전하게 대지로 방류시켜야 한다. 본 논문에서는 피뢰시스템에서 가장 흔하게 사용되는 수직접지전극을 대상으로 서지전류가 인가되었을 때 접지전극이 묻힌 대지저항률, 접지전극의 길이, 서지 전류의 파두시간 등에 따른 규약접지임피던스를 측정하고 그 특성을 분석하였다. 그 결과 대지저항률이 높은 토양과 접지전극의 길이가 짧은 경우 접지임피던스가 감소하는 용량성 특성이 지배적으로 나타나며, 대지저항률이 작고 접지전극의 길이가 긴 경우 접지임피던스가 증가하는 유도성 특성이 지배적으로 나타났다. 따라서 피뢰시스템을 위한 접지시스템 설계 시 대지저항률 및 접지전극의 길이를 고려하여 유도성 특성을 최소화 할 수 있도록 설계해야 한다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1187-1188
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• 2015

접지에 유입된 서지에 의해 각종 통신용 선로나 기기에 미치는 영향을 분석하고 이를 측정하기 위한 시험을 수행하였다. 통신용 케이블 접지에 서지 전류(8/20 us) 또는 링웨이브전류 ($0.5{\mu}s/100kHz$)가 흐를 때 발생되는 유기 전압을 측정하였다. 시험방법은 BNC 케이블의 접지에 서지 전류을 인가하였을 때 BNC 도선과 접지사이의 전압을 오실로스코프를 이용하여 측정하였으며, 시험 결과 서지 전류에 따라 유기 전압은 선형적으로 비례하여 증가되었다. 이를 통해 각종 통신용 보호소자 및 기기에 절연 설계에 참고 자료로 사용할 수 있다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.65-70
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• 2006

This paper presents the transient behaviors of grounding system impedance against lightning impulse currents. The dynamic characteristics of the deeply driven ground rod and grounding grid subjected to the impulse current were investigated. The transient ground impedance strongly depends on the configuration and size of grounding electrodes and the shapes of impulse currents, and the inductance of grounding electrodes has a significant affect on the transient ground impedance of grounding system Also, the deeply-driven ground rod was effective to reduce the transient ground impedance in time domain of miceroseconds.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.94-100
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• 2010

Grounding system insures a reference potential point for electric devices and also provides a low impedance path for fault currents or transient currents in the earth. The ground impedance as function of frequency is necessary for determining its performance since fault currents could contain a wide range of frequencies. In this paper, the grounding resistance, grounding impedance and transient grounding impedance are measured by using 3-point fall-of-potential method in order to analyse grounding characteristics of the stainless-steel plate grounding electrode. An equivalent transfer function model of the grounding impedance and transient grounding impedance are identified from the measured values by using ARMA method and evaluated by comparing conventional grounding impedances.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.62-68
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• 2008

This paper presents the transient and conventional grounding impedance behaviors of deeply-driven ground rods associated with the injection point of impulse currents. The transient grounding impedance strongly depends on the length of deeply-driven ground rod and the rise time and injection point of impulse currents, and the intrinsic inductance of ground rod has a significant affect on the transient grounding impedance of grounding system in fast rise time ranges. The reduction of inductance is decisive to improve the impulse impedance behaviors of deeply-driven ground rods. It is effective that grounding conductor is connected to the top of the ground rod as short as possible.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.6
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• pp.66-71
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• 2009

This paper presents the grounding impedance behaviors of counterpoise exposed to impulse currents. The transient and conventional grounding impedances of three counterpoises having the length of 10, 30 and 50[m] were measured and analyzed as a function of the injection point of impulse currents. As a result, the trend of the conventional grounding impedances measured as a function of injection of impulse current is similar to the transient grounding impedance of counterpoise. The injection point of impulse current has great influence on the transient grounding impedance characteristics of counterpoise. The transient grounding impedance characteristics in a short time range are strongly dependent on the length of counterpoise. The transient characteristics of grounding impedance of 10[m] counterpoise subjected to the impulse current was capacitive behavior, on the other hand, those of 30[m] and 50[m] counterpoises were inductive behavior. It is found that the grounding conductor should be connected to the central point of counterpoise.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.187-189
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• 2002

일반적으로 상용주파수에서의 대지는 입력전류의 크기에 따라 일정한 저항체로 다루어 질 수 있으며, 접지도체 임피던스도 무시할 수 있고 접지도체 전체가 등전위로 볼 수 있다. 그러나 써어지 전류 유입시에는 주파수가 수백 MHz 이므로 접지도체 임피던스에 의한 전압강하가 크게 될 뿐 아니라 써어지 전류 유입점의 도체전위가 매우 많이 상승하게 된다. 따라서, 본 논문에서는 운전중인 변전소 안전측면에서 접지임피던스와 보폭 및 접촉전압 등의 위험전압측정을 통한 안전성을 검토하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.4
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• pp.72-77
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• 2006

This paper presents the transient impedance behaviors according to the length of down conductors of grounding systems to lightning impulse currents. The potential rise and effective impulse ground impedance of the deeply-driven ground rod and grounding grid subjected to the impulse currents were measured and analyzed 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 waveform of impulse currents and the length of down conductors, and the installation methods reducing the inductance of down conductors are an important factor to decrease the transient ground impedances.