• 한국전기전자재료학회논문지
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• 제27권9호
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• pp.551-554
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• 2014

This paper was showed latch up characteristics of super junction power MOSFET by parasitic thyristor according to trench etch angle. As a result of research, if trench etch angle of super junction MOSFET is larger, we obtained large latch up voltage. When trench etch angle was $90^{\circ}$, latch up voltage was more 50 V. and we got 700 V breakdown voltage. But we analyzed on resistance. if trench etch angle of super junction MOSFET is larger, we obtained high on resistance. Therefore, we need optimal point by simulation and experiment for solution of trade off.

• 전기학회논문지
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• 제61권6호
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• pp.827-832
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• 2012

The crosslinked polyethylene (XLPE) is the most widely used insulating material for power cable. Due to its thermosetting characteristics, the XLPE can not be recycled, while the needs for the environmental friendly and recyclable insulator is rapidly increasing. In this paper, some important and basic electrical properties of non-crosslinked polyethylene such as conduction current characteristics, water the tree characteristics, AC breakdown test were experimentally investigated. It was shown that some of the tested samples had better performances from the application point of view for replacing current XLPE.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.293-295
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• 1987

This paper deals with the dielectric properties dielectric breakdown strength and mechanical tensile properties according to heat - treatment condition of polyurethane resin. This resin is heat - treated over a range of temperature from $50^{\circ}C$ to $150^{\circ}C$. It is shown that the dielectric dissipation factor decreases with increase of heat - treatment temperature of the sample exept for the sample heat - treated at $150^{\circ}C$. The maximum dielectric breakdown strength is appeared for the sample heat - treated for 10 hours at $100^{\circ}C$, after curing for 24 hours at room temperature. The optimal heat - treatment condition in the view point of the electrical and mechanical properties is appeared for the sample heat - treated for 10 hours at $100^{\circ}C$, after curing for 24 hours at room temperature.

• 한국컴퓨터정보학회논문지
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• 제4권4호
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• pp.133-139
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• 1999

본 논문은 현재 사용되고 있는 케이블의 진단을 위해서 열화가중치라는 새로운 접근법을 사용하였다. 케이블은 상시에 높은 온도로 운전된다는 점, 수분이 접촉할 확률이 크다는 점에서 신뢰성 있고 효율적인 열화진단은 필수적이라고 할 수 있다. 종래의 연구는 수트리가 발생되는 절연층을 주 대상으로 삼았으나, 현대에 와서는 절연층뿐만 아니라, 내·외부 반도전층 또한 활발한 연구가 이루어지고 있다. 본 연구에서는 최근에 국내에서 제안된 열화가중치법을 이용하여 케이블의 열화인자가 될 수 있는 부분에 대하여 특성분석을 수행한 다음, 열화가중치를 부여하여 케이블의 최종적인 상태를 파악해 보았다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1539-1541
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• 2000

Insulation layers in XLPE power cables may have some patterns generated in the manufacturing process. They are called 'flow patterns' and show flow history of molten polyethylene between inner and outer semiconducting layers. Flow patterns are even seen with naked human eyes and suspected to be inhomogeniety of insulation, weakening insulation performance. Investigated in this paper is electrical treeing resistance and ac breakdown strength according to flow patterns. Experiments of electrical treeing and ac breakdown strength by means of ramp tests were conducted using newly developed electrode system with point-to-plane structure and sphere-to-sphere structure, respectively. All results were analyzed with the application of statistics, showing little differences.

• 한국전기전자재료학회논문지
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• 제28권4호
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• pp.222-228
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• 2015

Power MOSFETs (metal oxide semiconductor field effect transistor) operate as energy control semiconductor switches. In order to reduce energy loss of the device, it is essential to increase its conductance. However, a trade-off relationship between the breakdown voltage and conductance of the device have been the critical difficulty to improve. In this paper, theoretical analysis of electrical benefits on single floating island power MOSFET is proposed. By the method, the optimization point has set defining the doping limit under single floating island structure. The numerical multiple 2.22 was obtained which indicates the doping limit of the original device, improving its ON state voltage drop by 45%.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.30-35
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• 2002

This paper dealt with FMEA, which is a method of the analysis to secure safety and confidence coming up to customers'expectation in consideration of the environment of the corporation, the industrial environment, and the functional improvement. And by using FMEA, We showed the example analyzed the confidence of the Air Supply System. It was proved by the result of the analysis that the rate of the breakdown which is usually regarded as the first important point to reform can't satisfy the selecting basis to improve. Also the result said that it is not right to depend on only the rate of the failure in making the list of the reform. Through the analysis of the breakdown, FMEA can present the important factors of the reform to improve the confidence of the system. In this study would show the important factors of the improvement in order to product the goods guaranteed confidence through the method of FMEA.

• 한국초전도ㆍ저온공학회논문지
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• 제11권2호
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• pp.29-32
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• 2009

The conduction cooling HTS SMES magnet is operated in cryogenic temperature. The insulation design at cryogenic temperature is an important element that should be established to accomplish miniaturization that is a big advantage of HTS SMES. However, the behaviors of insulators for cryogenic conditions in air or vacuum are virtually unknown. Therefore, we need active research and development of insulation concerning application of the conduction cooling HTS SMES. Specially, this paper was studied about high vacuum and cryogenic temperature breakdown and flashover discharge characteristics between cryocooler and magnet-coil. The breakdown and surface flashover discharge characteristics were experimented at cryogenic temperature and vacuum. Also, we were experimented about mechanical properties of 4-point bending test. From the results, we confirmed that about research between cryocooler and magnet-coil established basic data in the insulation design.

• International Journal of Safety
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• 제1권1호
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• pp.36-42
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• 2002

This paper is aimed at predicting the life of rubber insulating gloves under normal operating stresses from relatively rapid test performed at higher stresses. Specimens of rubber insulating gloves are subject to multiple stress conditions, i.e. combined electrical and thermal stresses. Two modes of electrical stress, step voltage stress and constant voltage stress are used in specimen aging. There are two types of test for electrical stress in this experiment: the one is Breakdown Voltage (BDV) test under step voltage stress and thermal stress and the other is lifetime test under constant voltage stress and temperature stress. The ac breakdown voltage defined as the break-down point of insulation that leakage current excesses a limit value, l0mA in this experiment, is determined. Because the very high variability of aging data requires the application of statistical model, Weibull distribution is used to represent the failure times as the straight line on Weibull probability paper. Weibull parameters are deter-mined by three statistical methods i.e. maximum likelihood method, graphical method and least squares method, which employ SAS package, Weibull probability paper and FORTRAN, respectively. Two chosen models for predicting the life under simultaneous electrical and thermal stresses are inverse power model and exponential model. And the constants of life equation for multistress aging are calculated using numerical method, such as Gauss Jordan method etc.. The completion of life equation enables to estimate the life at normal stress based on the data collected from accelerated aging test. Also the comparison of the calculated lifetimes between the inverse power model and the exponential model is carried out. And the lifetimes calculated by three statistical methods with lower voltage than test voltage are compared. The results obtained from the suggested experimental method are presented and discussed.

• 한국항공우주학회지
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• 제40권4호
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• pp.346-353
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• 2012

레이저 조사 시 발생되는 플라즈마를 성분 분석에 이용하는 Laser-Induced Breakdown Spectroscopy(LIBS)는 우주 자원 탐사에 적합한 실시간 성분 분석 기술이다. LIBS 플라즈마의 특성은 주위 압력의 영향을 크게 받는다. 본 연구에서는 다양한 물성치를 갖는 일곱 가지 원소(C, Ti, Ni, Cu, Sn, Al, Zn)의 지속시간(lifetime)이 760 - $10^{-5}$ torr의 압력 범위에서 분석되었다. 압력이 낮아짐에 따라 탄소와 티타늄의 lifetime은 감소하였고, 그 밖의 원소들은 1 torr의 압력에서 가장 오랜 시간동안 검출되었다. 원소별 lifetime 결과를 통하여 낮은 압력 하에서 플라즈마의 특성과 원소별 끓는점 및 전기음성도의 관계를 규명하였다.