• 조명전기설비학회논문지
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• 제24권7호
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• pp.41-46
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• 2010

With the improvement of industrial society, high quality electrical energy, simplification of operation and maintenance, and ensuring reliability are being required. Also we request an urgent change from $SF_6$ gas to an environment-friendly gas insulation material. In this paper, the experiments of breakdown characteristics by pressure and gap change of $N_2/O_2$ mixture gas through a GIS (Gas Insulated Switchgear) model were described. This paper reviews basic data of the surface discharge characteristics for Teflon resin in not only pure $N_2$, $N_2:O_2$ mixture gas as being focused on environmentally-friendly insulating gas, but also $SF_6$. Also, insulation characteristics by breakdown voltage and surface discharge voltage of $N_2:O_2$ mixture gas in the experimental chamber were studied.

• 전기학회논문지P
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• 제58권4호
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• pp.516-520
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• 2009

Atmosphere Plasmas of Gas Discharge (APGD) have been used in plasma sources for material processing such as etching, deposition, surface modification, etc. This study is to investigate and understand the fundamental plasma discharge properties. Especially, $SF_6/N_2$ mixed gas would be used in power transformer, GIS (Gas insulated switchgear) and so on. In this paper, we developed a one dimensional fluid simulation model with capacitively coupled plasma chamber at the atmosphere pressure (760 [Torr]). 38 kinds of $SF_6/N_2$ plasma particles which are an electron, two positive ions (${SF_5}^+$, ${N_2}^+$), five negative ions (${SF_6}^-$, ${SF_5}^-$, ${SF_4}^-$, ${F_2}^-$, ${F_1}^-$), thirty excitation and vibrational particles for $N_2$ were considered in this computation. The $N_2$ gases of 20%, 50%, 80% were mixed in $SF_6$ gas. As the amount of $N_2$ gas was increased, the properties of electro-negative plasma moved toward the electro-positive plasma.

• 한국전기전자재료학회논문지
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• 제34권6호
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• pp.426-432
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• 2021

Injection molding is used in many industrial fields such as home appliances, vehicle parts, and electronic device parts because various resins can be molded, leading to mass production of complex shapes. Generally, the empirical prediction method is used to set the initial processing conditions of injection molding. However, this approach requires a lot of cost and its presented solution is not accurate. In this paper, injection molding was simulated through the Moldflow^TM in order to manufacture the spacer for gas insulated switch. Through the simulation, the flow of the resin with respect to the diameter of the inlet was analyzed. It was found that the process was possible at a higher resin temperature as the diameter of the inlet increased. In addition, through thermal analysis during injection of the resin, it was confirmed that a stagnation phenomenon occurred at the insert portion during injection molding, and the temperature of the resin was higher than that of the mold. As in this paper, if the spacer is manufactured by optimizing the injection hole and the temperature of the injection process based on simulation, it is expected that the spacer can be manufactured with high productivity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1443-1444
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• 2007

지속적으로 증가되는 전기에너지 공급의 신뢰성을 높이기 위하여 전력설비 주요 사고 원인인 부분방전(PD : Partial Discharge)을 검출하고 결함원의 패턴인식 방법의 개발 필요성 날로 증가되고 있다. 본 논문은 부분방전의 패턴인식 확률을 높이기 위하여 검출된 부분방전의 주파수 분석을 이용하여 Conventional PRPD Analysis 방법의 결함 판독확률을 향상시키기 위하여 Advanced PRPD를 제안 한다. 이를 위하여, GIS(Gas Insulated Switchgear)의 주요 사고원인으로 인식되어 있는 결함들을 인위적으로 제작 후 삽입하여 부분방전을 발생시켜 자체 설계 개발된 UHF 내장형 센서를 이용하여 검출하였다. 새로이 제안하는 방법과 기존의 PRPD 방법의 인식률을 상호 비교하기 위하여, 두 가지 그룹을, 즉, 기존의 방법에 의한 것과 부분방전의 주파수 분석이 포함된 방법에 의한 데이터그룹을 구축하고 학습방법은 동일한 인공신경망 MLP (Multilayer Perceptron)를 이용하여 인식률과 학습시간을 동시에 비교하였다. 상호 비교 결과에 의하면, 후자의 방법이 인식확률 뿐만아니라 학습시간도 좋은 결과가 나타났다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.422-425
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• 2006

본 연구는 도체주변에 감겨진 광섬유 코일에 따라 선형편광축이 자기장에 의해 회전하는 Faraday Effect를 이용한 GIS(Gas Insulated Switchgear,이하 GIS) 용 광 전류센서의 구성과 DAQ(Data Acquisition,이하 DAQ)보드를 장착한 PC를 이용하여 실시간 데이터 취득, 분석 그리고 저장을 동시에 수행하였다 광원은 1310[nm]의 레이저 다이오드를 이용하였다. 센서부는 GIS에 맞게 원형으로 제작하였고 $9/125[{\mu}m]$규격 단일모드의 일반 통신용 광섬유를 지름 31[cm]의 센서부 코어에 20[회] 감아 설치하였다. PC기반의 실시간 데이터 분석 프로그래밍은 NI사의 Labview를 이용하여 코딩하였으며 PD(Photo Diode,이하 PD)의 전기적인 신호는 터미널 블록을 거쳐 NI사의 16bit DAQ M시리즈를 이용하여 수집되어진다. 직접 코딩한 프로그램을 이용하여 $700A\sim1400A$ 측정한 출력값 선형적인 증가추세를 보여주었다. 또한 OCS(Oscilloscope,이하 OCS)를 이용한 측정시스템과의 출력신호 및 정밀도를 비교 검토하였다. 그리고 Labview에서 지원하는 Web Tool기능을 이용하여 Web기반의 원거리 측정에서도 안정된 출력을 보여주었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1273-1274
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• 2007

In this paper, a Optical Voltage Transformer has been designed and fabricated to improve temperature stability caused by materials properties and insulation in measuring system, using single crystal $Bi_{12}SiO_{20}$ as Pockels effect cells for Gas Insulated Switchgear[GIS] System. LD[wavelength: 850nm] was used as optical source, InGaAs as optical detector to measure optical power, Polarizing Beam Splitter as Polarizer and Analyzer, and Multi-mode Optical-fiber[62.5/$125{\mu}m$] as Light transmission line. OPT was assembled in order to pockels effect, and adopted direct electric field type. The linearity of OPT maintains variation for applied voltage range from 100V - 3000V during the test of electric property, As the temperature was changed from $25^{\circ}C$ to $60^{\circ}C$. the result of this study shows that characteristics of OPT are good, and it can be reflected for practical optical sensors in GIS system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1400_1401
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• 2009

In this paper describes the comparisons of the surface flashover characteristics according to the change of the insulation media by experimental GIS(Gas Insulated Switchgear) chamber in accordance with change of pressure(P) and electrode distance(d). The using insulation medias are $SF_6$, Dry-Air, I-Air(Imitation Air, $N_2$ : $O_2$ = 79[%] : 21[%]), $N_2:O_2$ mixture gas and pure $N_2$. In this study, in order to compare the properties $SF_6$ and order insulation gas, we investigated the properties of the various insulation media with a knife to knife electrode under ac high voltage application. The gas pressure was changed from 1 to 5[atm]. as a result, it was found that dielectric strength is $SF_6$ > I-Air > Dry-Air and the best environmental preservation gas is Dry-Air.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2545-2552
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• 2018

$SF_6$ has been widely used in high voltage power equipment, such as gas insulated switchgear (GIS) and gas insulated transmission line (GIL), because of its excellent insulation and arc extinguishing performance. However, $SF_6$ faces two environmental problems: greenhouse effect and high liquefaction temperature. Therefore, to find the $SF_6$ substitute gases has become a research hotspot in recent years. In this paper, the liquefaction characteristics of $SF_6$ substitute gases were studied. Peng-Robinson equation of state with the van der Waals mixing rule (PR-vdW model) was used to calculate the dew point temperature of the binary gas mixtures, with $SF_6$, $C_3F_8$, $c-C_4F_8$, $CF_3I$ or $C_4F_7N$ as the insulating gas and $N_2$ or $CO_2$ as the buffer gas. The sequence of the dew point temperatures of the binary gas mixtures under the same pressure and composition ratio was obtained. $SF_6/N_2$ < $SF_6/CO_2$ < $C_3F_8/N_2$ < $C_3F_8/CO_2$ < $CF_3I/N_2$ < $CF_3I/CO_2$ < $c-C_4F_8/N_2$ < $C_4F_7N/N_2$ < $c-C_4F_8/CO_2$ < $C_4F_7N/CO_2$. $SF_6/N_2$ gas mixture showed the best temperature adaptability and $C_4F_7N/CO_2$ gas mixture showed the worst temperature adaptability. Furthermore, the dew point temperatures of the $SF_6$ substitute gases at different pressures and the upper limits of the insulating gas mole fraction at $-30^{\circ}C$, $-20^{\circ}C$ and $-10^{\circ}C$ were obtained. The results would supply sufficient data support for GIS/GIL operators and researchers.

• Transactions on Electrical and Electronic Materials
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• 제16권6호
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• pp.323-327
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• 2015

In this paper, parameters related with partial discharge (PD) were analyzed in SF₆ gas under AC and DC voltages. Three electrode systems (protrusion on conductor, protrusion on enclosure, and free particle) were fabricated to simulate PD defects in a gas-insulated switchgear (GIS). All electrode systems were filled with SF₆ gas at 0.5 MPa. PD pulses were detected using an oscilloscope and a data acquisition (DAQ) based on IEC 60270. To analyze the PD characteristics under AC and DC voltages, parameters such as discharge inception voltage (DIV), discharge extinction voltage (DEV), pulse magnitude, repetition rate, and T-F map were compared. From the experimental results, PD was revealed to have different characteristics under AC and DC, and these results may be useful for diagnosis of power facilities operated under HVDC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.767-769
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• 2002

최근 초고압 전력기기에 대한 많은 연구가 활발히 진행되고 있음에도 불구하고 통전용량에 크게 영향을 미치는 열해석에 대한 연구가 많이 부족한 실정이다. 본 논문에서는 초고압전력기기인 GIS(Gas Insulated Switchgear)의 모선에 대한 열해석을 다루었다. 해석방법은 유한요소법을 이용하여 온도상승을 예측하였다. 유한요소법은 3각형 등의 임의의 형상을 요소로서 채용할 수 있으므로 3상 모선과 같이 복잡한 형상도 표현할 수 있다. 열전달계수는 형상, 유동조건, 유체의 종류를 고려한 상관식을 이용하여 해석적으로 정확히 계산하였다. 열해석에 있어 자계해석을 통한 도체 및 탱크의 손실값산정이 선행되어야 하는데, 이 손실값이 온도상승의 원인이 되므로 정확히 계산하여야 한다. 손실의 원인이 되는 도체 및 탱크의 저항은 온도가 상승함에 따라 비선형으로 변화하는데, 이것을 고려하여 반복적으로 계산함으로서 해석의 정확성을 높이고자 하였다. 실제 모델에 대한 온도상숭 실험치와 본 논문에서 제시한 방법으로 해석한 계산치와의 비교를 통해 타당성을 입증하였다.