• 한국전자파학회지:전자파기술
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• 제6권4호
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• pp.57-61
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• 1995

일반적으로 서지발생기의 출력은 전원선을 통하여 피시험기에 전달된다. 이 논문에서는 전원선의 길이에 따라 전달되는 서지의 감쇄량을 이론적, 실험적으로 조사하였다. 서지출력은 전원선에 의해 비례적으로 감쇄되어 40m 전원선을 사용할 경우에 77%의 서지에너지만이 피시험기에 전달되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.285-288
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• 2001

The Railway Signalling Equipment's transformation to Micro-electronic has been caused to the decrease of its introspection against a surge voltage. So, there has been many tries to protect the railway signalling equipment from a surge voltage by using of a various surge protector. In this study, we are trying to draw up the protective plan to prevent this weakness on introspection by analyzing the electric characteristic on such a surge protector and reviewing the way on distributing wires in signalling room.

• Clinical and Experimental Reproductive Medicine
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• 제17권2호
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• pp.173-184
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• 1990

At infertility clinic, department of Obstetrics and Gynegology, Kyung Hee Medical Hospital, 80 patients who underwent IVF-ET from January to July, 1989 were evaluated for the prediction of endogenous LH Surge and its effects on outcome of controlled ovarian hyperstimulation (COH) were compared among LH Surge group without hCG given (N=18), with hCG given (N=5), and no-LH Surge group with hCG given (N=57). LH Surge were occurred in 23(28.7%) out of 80 patients studied. Serum E2 levels on Day-1, Day 0, Day+1, were no significant different among three groups. When basal serum LH/FSH ratio is above 1.0, the possibility of endogenous LH Surge is much higher (56.3% in LH Surge group without hCG given). Serum P4 levels on Day 0 were significantly increased in LH Surge group without hCG given. Cycles which serum P4 level is higher than l.0ng/ml were 70.6% of LH Surge group without hCG given. But there was no significant interrelationship between endogenous LH Surge and serum P4 rising rate as an efficient predictor of the occurrence of endogenous LH Surge in COH for IVF. There was no significant differences in number of follicles, follicular size on Day-1, Day 0, Day+1, and number of oocyte collected per cycle. The oocyte fertilization rate of No-LH surge group with hCG given was significantly higher than LH Surge group without hCG given. There was no significant difference in oocyte cleavage rate among three groups.

• 조명전기설비학회논문지
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• 제27권6호
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• pp.75-81
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• 2013

In this paper, protection coordination between residual current devices and surge protective devices in low-voltage consumer's distribution systems are presented. In the case that a surge protrctive device(SPD) is located on the load side of an residual current device(RCD), when the surge is injected from the source side of the RCD, most of injected surge currents are split into the RCD and the protection coordination between the SPD and RCD is improper, three of 6 specimens experience unintended operation due to test impulse currents. Also when the surges is injected from the load side, a lot of the surge currents is split into the SPD, but a half of test specimens causes nuisance trip. Coordination between SPD and RCD is not valid. When installing SPD, it is important to select SPD after due consideration of the protection voltage level of metal oxide varistor embedded in RCD. It is expected that the results obtained from this work could be useful to improve the protection effects of SPD in low-voltage distribution systems.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.127-131
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• 2002

The surge protector is crucial power apparatus to guarantee the safe operation of power transmission of underground cable which can effectively restrain the overvoltage and inductive lightning stroke in power system. The surge protector is crucial power apparatus to guarantee the safe operation of power transmission of underground cable which can effectively restrain the overvoltage and inductive lightning stroke in power system. This paper described the results of a study on the performance for surge protector for underground cable. And, the performance of surge protector was evaluated through such as measurement of the reference voltage, residual voltage and impulse current etc. In results of surge protector, reference and residual voltage of ZnO element is 4.75 kV, 9.86 kV respectively. Also, In the impulse current test, thermal properties are good, despite of that polymeric housing of surge protector has thick structure. Therefore the developed surge protector is thought to apply for underground cable.

• 한국유체기계학회 논문집
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• 제8권4호
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• pp.20-26
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• 2005

When the pumps are started or stopped for the operation or tripped due to the power failure, the hydraulic transients occur as a result of the sudden change in velocity. The field tests on the waterhammer were carried out for Pangyo booster pumping station in which had six booster pumps and two in-line pumps with the motor of output 1,700 kW, respectively. The booster pumping station was equipped with the pump control valve as the main surge suppression device, and the surge relief valve as auxiliary one. But the pump control valve had not early controlled in the planned closing mode, the slamming occurred to the valve of which abruptly closed during the large reverse flow. Because the positive pressure wave caused by the pump failure was superposed on the slam surge, the upsurge increased so extremely that the pump control valve was damaged. After the air chambers were additionally installed in the booster pumping station, it was preyed that the water supply system acquire the safety and reliability on the pressure surge.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권3호
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• pp.131-137
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• 2005

This paper describes a new approach to the algorithm and fundamental characteristics of the device for monitoring the leakage currents flowing through zinc oxide (ZnO) surge arresters. In order to obtain a technique for a new on-line monitoring device that can be used in the deterioration diagnosis of ZnO surge arresters, the new algorithm and on-line leakage current detection device for extracting the resistive and capacitive currents using the phase shift addition method were proposed. The computer-based on-line monitoring device can sense accurately the power frequency leakage currents flowing through ZnO surge arresters. The on-line leakage current monitoring device of ZnO surge arresters proposed in this work has the high sensitivity compared to the third harmonic leakage current detection devices. As a consequence, it was found that the proposed leakage current monitoring device would be useful for forecasting the defects and degradation of ZnO surge arresters.

• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.555-560
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• 2007

This paper describes the results of a study on the sealing integrity of polymer housed surge arrester based on the thermal mechanical test. The polymer housed surge arrester employs silicone insulating materials for its housing, instead of the conventional porcelain housing. The polymer housed surge arresters exhibited the highest sealing integrity because it is not air volume between the FRP(fiber reinforced plastics) module and the silicone housing. In accordance, the sealing integrity of station class surge arresters is investigated with moisture ingress test. And, the influence of sealing integrity was evaluated through such as measurement of the deflection, reference voltage, leakage current. In electrical characteristics, reference voltage decreased in the range of $16.45{\sim}16.15\;kV$ with after thermal mechanical test. In contrary, despite the continued moisture ingress, the polymer housed surge arresters exhibited almost the same leakage current value and the resistive leakage current has risen slightly. As a results, It was thought that the polymer housed surge arresters shows good stability with sealing integrity.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3732-3744
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• 2022

To investigate the effects of ocean conditions on the thermal stress and deformation caused by thermal stratification of a pressurizer surge line in a floating nuclear power plant (FNPP), the finite element simulation platform ANSYS Workbench is utilized to conduct the fluid-solid-thermal coupling transient analysis of the surge line under normal "wave-out" condition (no motion) and under ocean conditions (rolling and pitching), generating the transient response characteristics of temperature distribution, thermal stress and thermal deformation inside the surge line. By comparing the calculated results for the three motion conditions, it is found that ocean conditions can significantly improve the thermal stratification phenomenon within the surge line, but may also result in periodic oscillations in the temperature, thermal stress, and thermal deformation of the surge line. Parts of the surge line that are more susceptible to thermal fatigue damage or failure are determined. According to calculation results, the improvements are recommended for pipeline structure to reduce the effects of thermal oscillation caused by ocean conditions. The analysis method used in this study is beneficial for designing and optimizing the pipeline structure of a floating nuclear power plant, as well as for increasing its safety.

• 조명전기설비학회논문지
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• 제23권4호
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• pp.79-85
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• 2009

이 논문은 피임펄스전류의 입사에 따른 ZnO 피뢰기의 열화 특성에 대하여 기술하였다. 뇌서지에 의한 ZnO 피뢰기의 열화특성을 분석하기 위해 시료 ZnO 피뢰기에 8/20[${\mu}s$], 2.5[kA]의 표준뇌임펄스전류를 인가하였다. 뇌임펄스전류를 인가한 것과 인가하지 않은 ZnO 피뢰기에 흐르는 상용주파수 AC 및 DC 누설전류를 측정하였다. 그 결과 임펄스전류의 인가횟수가 증가함에 따라 누설전류는 증가하였고 AC전압에서 누설전류의 비 대칭성은 뚜렷하게 나타났다. 뇌임펄스전류를 인가하지 않은 ZnO 피뢰기의 ZnO 입자는 균일한데 반해 뇌임펄스전류를 인가한 ZnO 피뢰기의 ZnO 입자는 불균일하게 변형되었다. 또한 뇌임펄스전류 인가에 따른 $Bi_2O_3$의 감소가 입계층의 결핍을 발생시키며 입계층의 결핍에 의한 전류의 집중이 ZnO 피뢰기 소자의 비선형 특성의 열화에 대한 중요한 요인으로 작용한 것으로 밝혀졌다.