• 조명전기설비학회논문지
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• 제24권12호
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• pp.208-213
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• 2010

This paper deal with an analysis of the ground surface potential profiles using a hemispherical scaled-model. Because it is very difficult to draw valid conclusions concerning a general grounding problem from actual field data, scale model tests can be used to determine the ground surface potential profile around the grounding electrodes according to the configuration of grounding electrodes. In this work, a hemispherical vessel with a diameter of 1,100 [mm] was employed to simulate uniform soil and CDEGS program was employed to compare the measured and simulated results. As a result, the ground surface potential around the grounding electrode was significantly raised and the ground surface potential at the just upper point of ground electrode particularly was higher than other points. The ground surface potential of counterpoise was higher than other grounding electrodes such as mesh and grounding rods and the ground surface potential strongly depends on the frequency responses of grounding electrodes. Also the results measured with the small-sized model were in reasonably agreement with the data obtained from simulation.

• 조명전기설비학회논문지
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• 제24권5호
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• pp.114-121
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• 2010

본 논문에서는 대지저항률과 매설지선의 길이 그리고 접지전류의 인가점에 따른 매설지선 접지임피던스의 주파수 의존성에 대하여 살펴보았다. 단일 구조와 2층 구조의 대지에 설치된 매설지선의 접지임피던스를 1[kHz]에서 10[MHz]의 주파수 범위에서 측정하고 분석하였다. 그 결과, 접지임피던스의 주파수 의존성은 대지저항률에 크게 영향을 받는 것으로 나타났으며, 그리고 높은 대지저항률의 대지에 설치된 매설지선의 접지임피던스는 수십 [kHz] 이하의 주파수에서 용량성 특성을 나타내었다. 높은 대지저항률을 갖는 대지에 설치된 매설지선의 끝단에 접지전류를 인가한 경우 접지임피던스는 높은 주파수 영역에서 증가하였다.

• 전기학회논문지
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• 제60권3호
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• pp.479-485
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• 2011

In 22.9kV underground distribution system, power cables are provided with multiple-point ground in which each neutral line of the distribution cable(A, B, C phases) and three-wire common grounded at every connecting section. But in such grounding methods, circulating current flows between the neutral wire and grounding wire. And power loss due to circulating current also occurs in all conductors. Therefore it is getting necessary reducing circulating current in underground distribution system. This paper presents improved grounding method to overcome such problems. The proposed grounding method eliminates circulating current in the neutral line effectively and is verified that there is no electrical problem or any ineffectiveness of operating protection systems. These analyses are carried out by EMTP/ATPDraw to compare each grounding methods in steady and transient state. This grounding method suggested in this paper can be applied on real distribution system after field tests considering elimination of circulating current was implemented.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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• pp.231-234
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• 2004

Electrical grounding is defined as referencing an electrical circuit or a common reference plane for preventing shock hazards and for enhancing operability of the circuit and EMI control. In order to realize the best electrical grounding system of korean space launch vehicle, we should design the electrical grounding architecture of korean space launch vehicle of system-level at the earliest point in design procedure. To minimize the electrical grounding loop and the unnecessary electromagnetic interference or radiation among the electronic subsystems, we should establish the electrical grounding rules of the all electrical interfaces. The electrical interfaces among the electronic subsystems are generally classified into the electrical power and signal interfaces. Because of using the primary and secondary power system architecture in the korean space launch vehicle system such as the common space launch vehicle systems, we need to establish the electrical grounding rules between the primary and secondary power system. We also need to establish the electrical signal grounding interface rules among the electronic subsystems. In this paper, we will describe the grounding schemes of the common space launch vehicle system and propose a conceptual design for the electrical grounding architecture of korean space launch vehicle system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2355-2357
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• 1999

Estimating equivalent soil model which represents an actual soil structure and its electrical characteristics, is extremely improtant for good substation grounding system design and analysis. Since the equivalent soil model is deduced based on the measured apparent soil resistivity - generally obtained from Wenner's 4-point method, reasonable and accurate measuring technique and procedure guarantee good grounding system design and analysis. The paper aims to show the importance of reasonable enough probe spacing by presenting the influence of soil modelling to estimation and measurement of grounding resistance of substation grounding grid.

• 전기학회논문지P
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• 제62권4호
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• pp.159-163
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• 2013

In this paper, voltage quality improvement is analyzed in case of Superconducting Fault Current Limiter (SFCL) installed in grounding line of main transformer in power distribution system. First, a resistive-type SFCL model is used. Next, Korean power distribution system is modeled. Finally, when SFCL is installed in the starting point of feeder and grounding line of main transformer, voltage qualities are evaluated according to various fault locations and resistance values of SFCL using PSCAD/EMTDC. The voltage quality results in case of grounding line are compared with the voltage in case of feeder.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.291-295
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• 2005

This paper presents the modeling of grounding system on Korean electric railway system. The system model is composed of the catenary system, the grounding-system, the sub-sectioning post, the fault point, the sectioning post, the autotransformer in the substation, and the electric vehicle. The increment of rail-ground voltage may be thought as an amplifier of danger on human body of equipment insulation. The rail-ground voltage on steady state and on fault condition should be under standard limit voltage. To analyze grounding system for steady state and fault condition on Korean railway, modeling for each railway system is performed by 10-port network model. Modeling and analysis of present grounding-system are important to protect human and electronic equipments. The examinations for systematic grounding-system are investigated.

• 조명전기설비학회논문지
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• 제24권2호
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• pp.9-15
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• 2010

접지시스템은 전기설비의 기준 전위점을 확보할 뿐만 아니라 대지에 낮은 저항으로 고장전류나 과도전류를 흐르게 한다. 주파수에 대한 함수로 접지 임피던스는 고장이나 과도전류가 넓은 범위의 주파수 성분을 포함하기 때문에 접지성능을 평가하는데 필요하다. 콘크리트봉은 배전계통에서 널리 쓰이는 접지전극중의 하나이다. 본 논문에서는 콘크리트봉의 접지 임피던스를 주파수 60[Hz]에서 100[kHz] 범위까지 측정하여 등가 접지임피던스 모델을 구하였다. 뇌서지가 유입되었을 때 EDSA 프로그램으로 과도접지임피던스의 수치와 파형을 시뮬레이션 하였다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.297-300
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• 2008

This paper presents the behaviors of transient and conventional grounding impedances of a deep-driven ground rods associated with the injection point of lightning impulse currents. The transient impedance of deep-driven ground rods under lightning impulse currents were higher than the static ground resistance. The transient grounding impedances strongly depend on the injection point and size of grounding electrodes and the rising time of impulse current. Reduction of ground system inductance is an important factor to lightning surge protection.

• 조명전기설비학회논문지
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• 제23권8호
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• pp.26-32
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• 2009

접지시스템은 전기설비의 기준 전위점을 확보할 뿐만 아니라 대지에 낮은 저항으로 고장전류나 과도전류를 흐르게 한다. 주파수에 대한 함수로 접지 임피던스는 고장이나 과도전류가 넓은 범위의 주파수 성분을 포함하기 때문에 접지성능을 평가하는데 필요하다. 동봉은 배전계통에서 가장 많이 쓰이는 접지전극이다. 본 논문에서는 동봉의 접지 임피던스를 주파수 60[Hz] 에서 100[kHz] 범위까지 측정하여 등가 접지임피던스 모델을 구하였다. 뇌격서지가 유입되었을 때 EDSA 프로그램으로 과도접지임피던스의 수치와 파형을 시뮬레이션 하였다.