• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1570-1571
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• 2011

인접한 독립 접지전극에 접지전류가 인가된 경우 접지전극 상호간 전위간섭을 일으키게 된다. 상용주파수 접지전류에 대한 전위간섭은 많은 분석이 이루어 졌으나, 뇌서지와 같은 고주파수를 포함하는 접지전류에 대한 전위간섭의 분석은 충분히 수행되지 못하였다. 본 논문에서는 상호간 영향을 줄 수 있는 길이 4 m인 수직 접지전극을 대상으로 주파수에 따른 전위간섭의 영향을 분석하였으며, 수직 접지전극의 주변에 나타나는 대지표면전위와 함께 상호 비교 분석하였다. 그 결과, 전위간섭은 접지임피던스의 변화에 의존하는 경향성을 나타내었으며, 수직 접지전극 길이의 1.5배에 해당하는 이격거리에서 접지전극의 전위와 대지표면전위가 거의 일치하는 것으로 나타났다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.72-75
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• 2001

전력케이블 선로에 가해지는 전압은 상시교류전압이외에 지락 등에 의한 사용주파과전압과 뇌써지와 같은 써지성 과전압이 있다. 써지성 과전압이 케이블 심선에 침입할 경우 종단접속부나 절연접속함의 접속점은 절연통 양단 및 시스와 대지간에 고전압이 발생하여 케이블심선-시스간 시스-대지간의 써지임피던스 비에 따라 과전압이 발생하며, 이와 같이 써지성 과전압이 방식층의 충격내전압치를 초과할 경우 방식층을 보호하기 위한 대책이 필요하며 그 보호장치로 절연통 보호장치를 사용하는 것이 일반적이다. 절연통에 대한 보호대책과, 설계 제작된 절연통 보호장치에 대한 주요시험항목을 실시하여 항목별 그 특성을 검토하고 절연통 보호장치의 지중송전선로에서 사용되는 조건인 열적내량을 검증하는 충격전류시험과 침수에 의한 기밀성능을 검증하는 내수성능시험을 실시함으로써 그 중요성을 인식할 수 있었다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.37-43
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• 2010

When lightning surges with wide frequency spectrum and power converting devices are considered, it is desirable to evaluate grounding system performance by grounding impedances. This paper presents the measured results for frequency-dependent grounding impedance for the vertical grounding electrode and counterpoise on a scale of full size. Grounding impedances of vertical grounding electrodes and counterpoises give capacitive or inductive behaviors according to the length of grounding electrodes and soil resistivity. It is inefficient to extend the length of the grounding electrode in order to decrease the ground resistance, and when designing the grounding system, the consideration of the grounding impedance should be desirable. In order to reduce the grounding impedance of counterpoise, the grounding conductors are jointed at the center of counterpoises. It is effective to reduce the grounding impedance by connecting ground rods to counterpoises in parallel.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.234-238
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• 2001

시스템의 통합 운용 및 네트워크화로 장비간의 간섭과 노이즈에 대한 완화 및 효율적인 제거는 매우 중요한 문제로 대두되고 있다. 본 논문에서는 서지 및 노이즈의 간섭을 최소화하는 접지시스템의 구축 방안을 연구하였으며, 이를 위해 현장의 대지저항률을 실측하여 컴퓨터 시뮬레이션을 통해 정량적으로 분석하고, 현장에 최적의 접지시스템을 구축하기 위해 주파수에 따른 접지 임피던스 특성을 시뮬레이션하였으며, 접지계통으로 유입되는 서지의 경로 및 주파수 특성을 분석하였다.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.269-271
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• 2003

A method for calculation of mutual inductance from the parallel power-line and earth conduct to communication-line is studied in the paper. The solution for the electromagnetic field produced by an overhead power-line is derived using Maxwell's equations and treating the as a boundary value problem. Total mutual inductance from direct current and image current to communication-line is used Carson's formula for infinitely long parallel conductors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.5
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• pp.731-738
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• 2002

In this paper, we analyzed a medium voltage power line characteristics considering the skin effect for high speed data transmission. Medium power-line characteristics impedance was obtained by the S-parameter method which is used in high frequency band. Power line channel characteristics was measured using it designed coupler, it is a wide band coupler between medium powe-line and measurement system. Attenuation characteristics along the frequency was decreased linearly when skin effect was considered but attenuation characteristics along the frequency was decreased linearly when skin effect was not considered. Impedance was showed lower and lower in proportional to frequency, and variation was decreased in proportional to frequency.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.133-141
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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 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. Copper and concrete rod electrodes are the most commonly used grounding electrode in electric distribution systems. In this paper, the ground impedance of copper and concrete rods has been measured by frequency and time domain characteristic tests. An equivalent transfer function model of the ground impedance is 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.24 no.2
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• pp.9-15
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• 2010

Grounding insures a reference potential point for electric devices and also provides a law resistance path for fault or transient currents in the earth. The grounding impedance as a function of frequency is necessary for determining its performance since fault or transient currents could contain a wide range of frequencies. A concrete rod electrode is one of the commonly used grounding electrodes in electric distribution systems. In this paper, the grounding impedance of concrete rods has been measured in frequency raging from 60[Hz] up to 100[kHz] and an equivalent model of the grounding impedance is identified from the measured values. The grounding impedance under study when a typical lightning surge is injected into the grounding system was simulated numerically and graphically through the use of the EDSA software program.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.26-32
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• 2009

Grounding insures a reference potential point for electric devices and also provides a law resistance path for fault or transient currents in the earth. The ground impedance as a function of frequency is necessary for determining its performance since fault or transient currents could contain a wide range of frequencies. A copper rod electrode is the most commonly used grounding electrode in electric distribution systems. In this paper, the grounding impedance of copper rods has been measured in frequency raging from 60[Hz] up to 100 [kHz] and an equivalent model of the grounding impedance is identified from the measured values. The grounding impedance under study when a typical lightning surge is injected into the grounding system was simulated numerically and graphically through the use of the EDSA software program.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.109-115
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• 2008

A design criterion of grounding systems is commonly based on the ground resistance measured with low frequency in Korea. When lightning surges which have high frequency components are injected into the grounding system, the grounding impedance is great]y different from the static grounding resistance. In order to investigate the effect of water resistivity on the high frequency performance of grounding systems, this paper presents the frequency-dependent admittance using water tank simulating the grounding system in different water resistivities. As a result, because of capacitive effect admittances and conductance are increased with increasing frequency in higher water resistivity of greater than 500[${\Omega}{\cdot}m$]. On the other hand, admittances and conductances are decreased with increasing frequency due to inductive effect in lower water resistivity of less than 500[${\Omega}{\cdot}m$]. The phase difference between the current and voltage increases in the range of 200[kHz] to 5[MHz]. Consequently, frequency-dependent performance of grounding systems is closely related to the soil resistivity, it is necessary to consider the effect of grounding system performance on the frequency and soil resistivity.