• 조명전기설비학회논문지
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• 제20권10호
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• pp.164-171
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• 2006

본 연구에서는 연소화염이 존재할 때, 상용주파수 교류 및 직류 고전압에 대한 모델전력선의 절연파괴특성을 조사한 결과를 보고하였다. 화염높이와 위치에 따라 절연내력은 크게 저하되며, h=0에서 교류 및 직류 절연파괴전압은 화염이 없는 경우보다 최대 80[%] 저하되는 것으로 나타났다. 또한 화염위치가 k=0.5일 때 화염높이에 대한 영향도 조사하였으며, 교류전압 인가 시 h=0, 3, 6, 9 및 12[cm]로 변화시킨 경우, 화염이 없는 경우의 절연파괴전압에 비해 각각 78.6[%], 59.7[%], 46.9[%], 41.5[%] 및 35.4[%] 저하된 것으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.916-918
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• 1998

Degradation diagnosis of XLPE insulated URD cables was accomplished through out new method which was to be analyzed by non-electrical experiments and synthesized by degradation points. To supplement this method, It was also carried out using several electrical analyses PD-q increased generally in proportion to the applied voltage and showed no uniform patterns in relation to the thickness of insulator. Leakage current was unequal according to the thickness of insulator and its range was from 20[nA] to 50[nA]. $Tan{\delta}$ had commonly a different tendency by means of temperature and frequency and also appeared higher at the outer part rather than inner part of insulator. Breakdown voltages were measured and breakdown lifetimes were predicted appling for Weibull distribution function. As a result, breakdown lifetime in failure cables was longer up to three times as much as general cables.

• 한국초전도ㆍ저온공학회논문지
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• 제15권4호
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• pp.10-14
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• 2013

We have clearly investigated with respect to the survival of the insulator at cryogenic temperature under the electrical stress. The breakdown and voltage-time characteristics of turn-to-turn models for point contact geometry and surface contact geometry using copper multi wrapped with polyimide film for an HTS transformer were investigated under AC and impulse voltage at 77 K. Polyimide film (Kapton) 0.025 mm thick is used for multi wrapping of the electrode. As expected, the breakdown voltages for the surface contact geometry are lower than that of the point contact geometry, because the contact area of the surface contact geometry is lager than that of the point contact geometry. The time to breakdown t50 decreases as the applied voltage is increased, and the lifetime indices increase slightly as the number of layers is increased. The electric field amplitude at the position where breakdown occurs is about 80 % of the maximum electric field value. The relationship between survival probability and the electrical stress at cryogenic temperature was evident.

• 한국전기전자재료학회논문지
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• 제25권4호
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• pp.309-314
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• 2012

To assess the condition of stator insulation, nondestructive and overpotential tests were performed on four high voltage motors. The stator windings under these tests have nominal ratings of 6.6 kV. After completing nondestructive tests, the AC overvoltage applied to the stator windings was gradually increasing until insulation failure in order to obtain the breakdown voltage. No. 1, No. 2, No. 3 and No. 4 of 6.6 kV motors failed near rated voltage of 18.4 kV, 19.8 kV, 19.7 kV and 21.7 kV, respectively. The breakdown voltage of four motors was higher that expected for good quality coils(14.2 kV) in 6.6 kV motors. Almost all of failures were located in a line-end coil at the exit from the core slot. The breakdown voltages and the types of defects showed strong relation to the stator insulation tests such as in the case of AC current, dissipation factor($tan{\delta}$) and partial discharge magnitude.

• 한국초전도ㆍ저온공학회논문지
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• 제7권2호
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• pp.21-26
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• 2005

Breakdown characteristics and survival probability of turn-to-turn models were investigated under ac and impulse voltage at 77K. For experiments, two test electrode models were fabricated: One is point contact model and the other is surface contact model. Both are made of copper wrapped by O.025mm thick polyimide film(Kapton). The experimental results were analyzed statistically using Weibull distribution in order to examine the wrapping number effects on voltage-time characteristics under ac voltage as well as under impulse voltage in LN$_{2}$. Also survival analysis were performed according to the Kaplan-Meier method. The breakdown voltages of surface contact model are lower than that of point contact model, because the contact area of surface contact model is wider than that of point contact model. Besides, the shape parameter of point contact model is a little bit larger than that of surface contact model. The time to breakdown t$_{50}$ is decreased as the applied voltage is increased, and the lifetime indices slightly are increased as the number of layers is increased. According to the increasing applied voltage and decreasing wrapping number, the survival probability is increased.

• 한국정보통신학회논문지
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• 제17권5호
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• pp.1196-1202
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• 2013

본 연구에서는 이중게이트 MOSFET에 대한 항복전압의 변화를 채널도핑 및 소자파라미터에 따라 이차원 전위분포모델을 이용하여 분석한 것이다. 낮은 항복전압은 전력소자동작에 저해가 되고 있으며 소자의 크기가 감소하면서 발생하는 단채널 효과에 의하여 이중게이트 MOSFET의 경우도 심각하게 항복전압이 감소하고 있다. 항복전압분석을 위하여 포아송방정식의 이차원 해석학적 전위분포모델을 이용하여 채널도핑농도와 소자 파라미터인 채널길이, 채널두께, 게이트산화막 두께 등에 대하여 항복전압의 변화를 관찰하였다. 분석결과 항복전압은 채널도핑 농도의 크기뿐만이 아니라 소자크기 파라미터에 대해서 커다란 변화를 보이고 있었으며 특히 채널도핑함수인 가우시안 함수의 형태에 따라서도 큰 변화를 보이고 있다는 것을 관찰할 수 있었다.

• 조명전기설비학회논문지
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• 제16권1호
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• pp.106-113
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• 2002

본 연구는 방전쳄버내에 각종 가스의 압력(58.8-137.3[kPa]) 변화에 따른 순수가스인 Kr, Ar 및 $N_2$가스의 절연 특성을 조사하고, 혼합가스인 Ar/$N_2$및 Kr/$N_2$가스의 절연 특성과 비교하였다. 또한, 실용 백열전구내의 혼합가스에 위한 각종 특성을 조사하였다. 실험 결과, $N_2$가스의 압력변화에 따른 절연 특성은 큰 분자량을 가진 Kr 및 Ar가스에 비하여 증가되었으며, 가스의 압력이 증가됨에 따라 절인파괴전압은 증가되었다. Ar/$N_2$및 Kr/$N_2$가스의 절연파괴전압은 $N_2$가스의 혼합비가 적을수록 감소되었으며, Kr(70%)$N_2$(30%)가스의 코로나개시전압은 Ar(70%)/$N_2$(30%)가스에 비해 증가되었다. 일반 백열전구에 Ar(70%)/$N_2$(30%)가스인 경우에 비해, Kr(70%)/$N_2$(30%)가스에서 광속과 수명이 대략 94[lm] 및 380[hr]으로 증가되었다. 백열전구내의 냉각온도가 20[$^{\circ}C$]일 때 혼합가스 주입압력은 40[$^{\circ}C$])에 비해 대략 13[%] 증가되었다.

• 한국진공학회지
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• 제22권6호
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• pp.335-340
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• 2013

본 논문은 InP 식각정지층을 갖는 MHEMT 소자의 항복전압을 증가시키기 위한 시뮬레이션 설계 논문이다. MHEMT 소자의 게이트 리세스 구조 및 채널 구조를 변경하여 시뮬레이션을 수행하였고 비교 분석하였다. MHEMT 소자의 드레인 측만을 완전히 제거한 비대칭 게이트 리세스 구조인 경우 $I_{dss}$ 전류가 90 mA에서 60 mA로 줄어들지만 항복 전압은 2 V에서 4 V로 증가함을 확인하였다. 이는 $Si_3N_4$ 보호층과 InAlAs 장벽층 사이의 계면에서 형성되는 전자-포획 음의 고정전하로 인해 채널층에서의 전자 공핍이 심화되어 나타나는 현상으로 이는 채널층의 전류를 감소시켜 충돌이온화를 적게 형성시켜 항복전압을 증가시킨다. 또한, 동일한 구조의 비대칭 게이트 리세스 구조에서 채널층을 InGaAs/InP 복합 채널로 바꾸어 설계한 구조에서는 항복전압이 5 V로 증가하였다. 이는 높은 드레인 전압에서 InP 층의 적은 충돌이온화와 이동도로 인해 전류가 더 감소했기 때문이다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 춘계학술대회 논문집
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• pp.24-26
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• 1988

The electrical properties of thin nitrided thermal oxides prepared by rapid thermal nitridation(RTN) have been studied. The flatband voltages were calculated using C-V measurement and found to vary as nitridation time and temperature. After nitridation an increase in the fixed oxide charge density was always observed, but the distribution of it as a function of annealing time was found to be random. The breakdown voltages were measured using curve tracer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.1084-1086
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• 1999

The breakdown was caused by particle in GIS and various methode was suggested to find particle in GIS. In this paper, four states of particle was imitated which are particle on electrode, particle on enclosure, particle on spacer and crossing particle. The discharge voltage of each states was classified by four voltages which are initial, development, later and close discharge voltage. $\Phi$-Q-N pattern was analyzed according to the states and to the discharge voltages. In the result, the electrical discharge pattern according to the particle states may be distinguished.