• 조명전기설비학회논문지
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• 제21권7호
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• pp.37-45
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• 2007

최근 뇌보호용 접지시스템 심매설 봉전극을 사용하는 경우가 늘고 있다. 심매설 봉전극의 경우에는 수직으로 깊게 봉전극을 시설하기 때문에 메시그리드 전극에 비해 장소의 제약을 덜 받는 장점이 있지만 국지적인 대지저항률에 의해 접지임피던스가 크게 변동하므로 설계시에 세밀한 대지구조의 분석이 필요하다. 기존의 Wenner법에 의한 대지저항률 측정은 널리 사용되는 방법이지만 국지적인 대지저항률의 변화를 알아내기가 불가능하였고 또한 겉보기 대지저항률로 측정결과가 나타나므로 정확한 깊이를 예측하기가 어렵다. 따라서 본 연구에서는 96채널 측정설비를 이용하여 대지구조를 2-D 이미지로 분석하였으며, 뇌보호용 심매설 전극을 효과적으로 설계하기 위해 국지적인 대지저항률 변동 및 대지층 깊이의 분석을 시도하였다. 대지저항률의 2-D 이미지 분석은 Wenner alpha법, Dipole-dipole법, Schlumberger법을 사용하였으며, 분석결과를 토대로 기존의 Wenner 1-D법으로 측정한 결과를 CDEGS로 분석한 대지구조와 비교하였다.

• International Journal of Safety
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• 제7권1호
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• pp.21-25
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• 2008

The occurrence of a corona is that electrical discharge due to the heterogeneity that occurs when an electrical field is concentrated in an electrode due to a cusp formed on said electrode. Wire treatment at the end of a 154kV dead end clamp for end users accelerates the occurrence of corona, which in turn leads to power loss and noise. In this study, the characteristics of the corona which occurs between porcelain insulators and support clamps of overhead lines used in l54kV power receiving facilities for end users were investigated. The corona, which cannot be identified by one common method, was measured utilizing a UV image camera. A risk assessment for fire damage and its status was suggested. The stress distribution of the electrical field by length of bare wire was suggested by means of the finite element method (FEMLAB). As a result, it was found to affect a porcelain insulators. These results can be utilized for the enhancement of clamp installation and safety in power facilities.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.349-351
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• 2001

Because of the continuous growth of energy consumption and also the tendency to site power lines and pipelines along the same route, the close proximity of power lines and buried metallic pipelines has become more and more frequent. Therefore there has been and still is a growing concern about possible hazards resulting from the influence of power lines on metallic pipelines. When a ground fault occurs in an electrical installation the current flowing through the earthing electrode produces a potential rise of the electrode and of the neighbouring soil with regard to a remote earth. This paper analyzes the effects of ground faults when the current will flow into the soil from the foot of 345kV transmission line tower.

• Geomechanics and Engineering
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• 제30권4호
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• pp.337-343
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• 2022

The electrical resistivity method is a well-known geophysical method for observing underground conditions, (such as anomalies) and the properties of soil and rock (such as porosity, saturation, and pore fluid characteristics). The shape of electrodes used in an electrical resistivity survey depends on the purpose of the survey and installation conditions. Most electrodes for field applications are cylindrical for sufficient contact with the ground, while some are conically sharpened at their tips for convenient penetration. Previous study only derived theoretical equations for rod-shaped electrodes with spherical tips. In this study, the theoretical resistance for two cylindrical electrodes with conical tips is derived and verified experimentally. The influence of the penetration depth and tip on the measurement is also discussed.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.203-207
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• 2007

Recently, ozone is utilized in various fields and its needs are expanding. In this paper, plate type ozonizer have been fabricated to investigate discharge parameter(input power, flow rate of supplied gas, electrode form, etc.) effect to discharge. And the conditions of discharge parameter have been investigated for optimum ozone generation. Ozone concentration is continuously increased with increasing input power for same discharge space, and ozone yield is also increased until maximum point after that it is saturated. Ozone concentration is inversely proportional to flow rate of supplied gas but ozone generation and ozone yield characteristics are improved.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.251-255
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• 2002

This paper describes the analysis of UHF signals taking place at partial discharges due to defects in GIS. To imitate the defects, two kinds of electrode were employed. One is to generate the PD due to corona discharge, and the other surface discharge. As a result, the magnitude of the UHF signals acquired from the discharges increased with the applied voltage. However, each frequency distribution trend at corona discharges and surface discharge was similar even though the applied voltage increased. Frequency distribution between corona discharge and surface discharge was clearly distinguish.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.193-197
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• 2001

In this paper, reduction characteristics of the ac flashover voltage in the horizontal air gap of sphere-sphere and needle-needle electrode system were investigated when the combustion flame was present near the high-voltage electrodes. The reduction characteristics of ac flashover voltage were discussed with thermal ionization process, the relative air density and the deflection phenomena in the shape of flames that changed by the corona wind and coulomb's force. As the results of an experimental, It was found that the reduction of flashover voltage in sphere-sphere system, in comparison with the no-flame case, are 79.9 [%] for k=0, 82.9 [%] for k=0.5, 87.5 [%] for k=1.0, 85.0 [%] for h=0 [cm], 40.8 [%] for h=5 [cm] and 28.2 [%] for h=9 [cm] when ac voltage is applied.

• 조명전기설비학회논문지
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• 제17권6호
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• pp.1-6
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• 2003

본 연구에서는 광원의 색온도와 연색성의 차이에 의한 밝음의 느낌을 연구하기 위하여 이종 램프간, 또한 동종 램프 간의 비교 실험을 시각 대상물로 흑백 인쇄문자지와 색상지를 사용하여 수행하였다. 백열전구, 형광램프, 고압 나트륨램프, 메탈헬라이드램프, 무전극 방전램프를 대상으로 실험을 수행한 결과, 이종 광원의 경우 밝음의 느낌 비는 백열전구를 제외한 광원의 경우 대체적으로 평균연색계수에 비례하는 경향이 있으며, 모든 시험 대상 광원의 경우 색온도에 비례하는 것으로 나타났다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 학술대회 논문집
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• pp.335-338
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• 2004

In this paper the experiments of insulation characteristics by temperature change of $SF_6$ gas and insulation characteristics about liquid $SF_6$ in GIS(Gas Insulated Switchgear) were described. From this result, at low temperature, the breakdown voltage was increased with a drop of temperature and an increase of the inner pressure in GIS. The ability of insulation in liquid $SF_6$ was higher than that of the highly pressurized $SF_6$ gas. A liquid $SF_6$ discharge characteristics was caused by bubble formed evaporation of liquid $SF_6$ and bubble when high voltage apply to electrode. Corona was happened to weak bubble and was proceed to new bubble breakdown.

• 조명전기설비학회논문지
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• 제25권4호
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• pp.38-44
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• 2011

Grounding electrodes with higher burial depths are evaluated to have better performance, due to the domestic practice that puts the grounding resistance as the standard of performance evaluation, while grounding resistance decreases as the burial depth increases. However, The dangerous voltage is necessary for the analysis. Because the performance evaluation of grounding electrodes should include not only grounding resistance but also the dangerous voltage(mesh voltage and step voltage). So in this paper, The dangerous voltages of mesh grounding and rod grounding were analyzed for using computer simulation and miniature grounding model.