• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1972-1974
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• 2000

In this paper, we made an experiment on fault location of underground cables with travelling wave. The 5C2V coaxial cables of 100, 200m length, connected with discharge gap, are used for simplifying model cable lines of power cable. And 100KHz -2MHz CT and HV probe are installed at one side of the ends. We made travelling pulse in discharge gab and then pulse travelled along the cable to the both ends. Therefore, it is detected in CT and HV probe. Measuring the time difference of the pulse start and arrival, we were able to obtain the distance of pulse travelling. Consequently, our experimental results show the possibility to detect fault location of underground cables with travelling wave.

• 대한전기학회논문지
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• 제36권11호
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• pp.806-812
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• 1987

The ozone generation characteristics are reported for a sawtooth disk to cylinger geometry using positive and negative pulse corona. A series of parametric studies was carried out to obtain optimum values for the pulse repetition frequency as well as the shape and dimensions of the discharge disk and the discharge spacing. Two types of ozonizers were studied: the single disk and the multi-disk. The results of the single disk ozonizer showed that positive corona produced a singificantly higher ozone yield than negative(7ppm/peak watt or 3.5 times larger). However the negative corona produced a much more controllable output which enabled the ozone generation to be directly controlled by adjusting the value of the peak pulse voltage. This results showed that the single disk ozonizer is ideally suited for applications requiring very small controlled quantities of ozone whereas the multi-disk unit can be designed to provide varying outputs depending upon the number of disk electrodes used.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1852-1854
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• 2003

In manufacturing processes, various and suitable pulse shapes are required for the purpose of material processing. In order to make various pulse shapes with variable pulse length and high duty cycle, We have fabricated the power supply consisting 6 SCRs and the Pulse Forming Network(PFN) with the precise delay time control. So our control system has three switching circuits, 3 mesh PFN, and simmer circuit. In addition, we have designed and fabricated the PIC one-chip microprocessor(16F877) to control the delay time of sequential switching.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1167-1169
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• 1996

As electrical discharge machinery(EDM) is industrial process which is manufactured by discharge energy, by producing discharge, EDM process finished material at the little micrometer air gap. Especially, EDM is used for the characteristic of heat-resisting material, it puts to use air-space industrial element, confusing shaping material such as jet engine, rocket elements. Working performance. is changed by environment of working, discharge current voltage and duration of discharge pulse. Evaluation of performance working is work speed, clearance smoothing of product surface, wasting of pole. In this paper, this machine is compensated by adaptive controller which corrects the weak points of classical machine which is observed and operated working condition by user in hands. The previous purpose is main object in this thesis. The adaptive controller automatically detect abnormal condition and working conditions. To improve performance, surface smoothing and working speed, the adaptive controller uses fuzzy control strategy. To evaluate performance, this controller is implemented by microprocessor i80c196 and is applied real experimental machine.

• 한국수자원학회논문집
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• 제56권12호
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• pp.871-881
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• 2023

본 연구에서는 영주댐 하류 하천을 대상으로 2차원 수치모형인 Nays2DH를 적용하여 펄스방류 등 다양한 유량 조건에서 하류 하천의 역동성을 파악하기 위해 하도의 지형변화 특성 및 하상기복지수를 분석하였다. 수치모의에 적용되는 유량패턴은 등류 흐름, 정규화된 단일홍수, 펄스방류, 그리고 정규화된 펄스방류 등 4개의 유형이다. 수치모의 결과, 정규화를 적용한 펄스방류 조건일 때 하상고 및 하도의 변화가 가장 큰 것으로 나타났다. 총 하상 변화량은 등류 흐름 조건일 때 29.88 m, 정규화된 단일 홍수 조건일 때 27.46 m, 펄스 방류일 때 29.63 m 그리고 정규화된 펄스 방류일 때 31.87 m로이며, 이 조건에서 세굴과 퇴적의 변동 폭이 가장 크게 나타났다. 하상기복지수(BRI)를 분석한 결과, 등류 조건, 펄스방류, 그리고 정규화된 펄스방류 조건은 시간이 지날수록 BRI가 증가한다. 그러나, 정규화된 단일홍수에서는 첨두유량(14 hrs) 이후 30 hrs 까지 BRI가 급격하게 증가하지만, 그 이후부터는 증가 폭이 점점 감소하고, 56 hrs부터는 감소하였다. 수치모의가 끝날 때(72 hrs) BRI는 등류일 때 2.95, 정규화된 단일홍수일 때 3.31, 펄스방류일 때 3.34, 정규화된 펄스방류일 때 3.78이다. 따라서, 정규화된 펄스방류가 단일홍수나 등류보다 더 큰 역동성을 줄 수 있고, 하류로 갈수록 역동성이 커지면서 댐 하류하천의 환경개선에 효과를 가져올 수 있을 것으로 기대한다.

• 전기학회논문지
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• 제67권4호
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• pp.549-553
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• 2018

The applications of the pulse power technology are expanding and the necessity of a large current switch as a core component of pulsed power is increasing. A trigger gap switch composed of three electrodes was fabricated and the discharge characteristics were studied according to the change of the pressure, the shape of the main electrode, and the gap distance when the trigger pulse was applied. As a main result, the stable operation range was confirmed through the discharge inception voltage according to the gap distance and electric field analysis was performed in the same structure to confirm the electric field value of the discharge inception voltage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1991년도 추계학술대회 논문집
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• pp.83-89
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• 1991

The partial discharge properties of interface layer in Mica-Epoxy composite, which has been mainly used for the coil insulating material of high voltage machinery, are different from those of resins due to the abnormal interface layer to be presented between inorganic material and resin. Accordingly, the study on discharge of interface in composite insulting system is strongly requsted for not only an increasing of insulating strength, but also the basical information of diagnosis system for high voltage equipment. As a result, it has been confirmed that the interface is an abnormal resin layer and the contact states at interface is depended upon the density of silane aqueous solution. Pulse frequency at abnormal interface shows a linear increasing with enlargement of discharge quantity. Whereas, in case of normal interface, pulse frequency property represents exponential increasing at the point of saturating. A life model can be diagramed from results of time dependance of skewness, and a survival life time can be quantified from the life model suggested.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.95-98
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• 2003

The positive column discharge characteristics in the long gap (440 ${\mu}m$) are investigated based on the voltage distribution among three electrodes. In particular, the effects of the amplitude and width of the short pulse applied to the address electrode on the positive column discharge characteristics are examined intensively. By proper controlling of the amplitude and width of the address short pulse, it is found that the positive column discharge in the long gap is well constructed. As a result, under the stable static voltage margin condition, the firing and sustaining voltages are as low as those of conventional short gap(60 ${\mu}m$) discharge($V _f=220V$, $V_s=150V$) and the color purity is improved. Moreover, the luminous efficiency increases up to 60% in comparison with the conventional case.

• 전기학회논문지
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• 제64권9호
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• pp.1281-1287
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• 2015

We report the characteristics and differences of two types of attenuation measurement methods for electromagnetic partial discharge signal in GIS. The pulse method is to measure the attenuated waveforms in time domain and coverts them into frequency domain to get the attenuation spectra of given GIS section. This method simulates the real partial discharge signal. The frequency swept continuous wave method can obtain attenuation spectra directly so that it gives attenuation with low noise floor and simplicity. We show that both methods are effective and exchangeable because the attenuation results measured by two methods have similar trends

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 추계학술대회 논문집
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• pp.128-131
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• 1992

In this paper, the skewness properties of partial discharge at interface layer in mica-epoxy composite material were investigated and studied on interface specimens which has internal electrodes. As a result, it has been confirmed that the interface exists as abnormal resin layer and the contact condition at the interface is depended upon the density of si lane aqueous solution. The Pulse frequency of discharge at abnormal interface has been shown a linear increasing with enlargement of discharge quantity according to rising of the applied voltage. Whereas, in case of normal interface, pulse frequency represented exponential increasing at the saturating point of discharge quantity. The aging model can be represented from the variable characteristics of skewness.