• 한국안전학회지
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• 제33권2호
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• pp.21-27
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• 2018

The expansion and stable operation of electric power facilities are important factors with development of industrial facilities in modern society. In high-voltage equipment such as GIS, the insulation characteristics may be deterioated by environment-friendly gas adaption and miniaturization. There is also the possibility of accidents due to insulation breakdown due to the deterioration of power facilities. Therefore, it is necessary to extend the diagnosis system to continuously monitor the danger signals of these power equipment and to prevent accidents. Most of the internal defects in the GIS system are conductive particles, floating electrode defects, protrusion defects, and the like. In this case, a partial discharge phenomenon is accompanied. These partial discharge signals occur irregularly and various noise signals are included in the field, so it is difficult to evaluate the reliability in the development of the diagnostic system. In this paper, a study was made on equipment capable of generating a partial discharge simulated signal that can be adjusted in size and frequency to be applied to a diagnostic device by electromagnetic wave detection method. The PD simulated pulse generator consists of a user interface module, a high-voltage charging module, a pulse forming circuit, a voltage sensor and an embedded controller. In order to simulate the partial discharge phenomenon similar to the actual GIS, a discharge cell was designed and fabricated. The application of the prototype pulse generator to the commercialized PD diagnosis module confirmed that it can be used to evaluate the performance of the diagnostic device. It can be used for the development of GIS diagnosis system and performance verification for reliability evaluation.

• 전기학회논문지
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• 제56권1호
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• pp.151-155
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• 2007

A compact discharge plasma system with a photocatalyst has been proposed and investigated experimentally for application to air conditioners. It was found that there was intense ultra violet radiation with high energy of 3.2 eV from the corona discharge due to the DC-biased pulse voltage applied on a wire. An electrophotochemical reaction took place apparently on the surfaces of the photocatalyst of $TiO_2$ irradiated ultra violet front the discharge plasma in the proposed plasma system. The proposed discharge plasma system with the photocatalyst of $TiO_2$ showed very high removal efficiency of VOCs by tile additional electrophotochemical reactions on the photocatalyst. The proposed discharge plasma system also showed very high removal efficiency of particles such as smokes, suspended bacteria, and pollen and mite allergens by the electrostatic precipitation part. This type of corona discharge plasma system with a photocatalyst can be used as an effective means of removing both indoor pollutant gases and particles including suspended allergens.

• 한국CDE학회논문집
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• 제4권4호
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• pp.355-359
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• 1999

This paper presents a method for determining machining parameters in electrical discharge machining process (EDM) based on discharge area. The parameters are the peak value of currents, the pulse-on time, and the pulse-off time, on which the EDM performance depends chiefly. The optimal machining parameters are closely related on discharge area, which can be calculated from a tool electrode and a discharge height. In the paper the discharge area is obtained from NC code for machining the tool electrode instead of its geometric model. The method consists of following three steps. First a Z-Map model is constructed from the NC code. Secondly, the discharge area is obtained from the Z-Map model and a Z-height. Finally, the machining parameters are calculated from the discharge area. An introduced example shows that the machining parameters are calculated by the using a Z-map model obtained from the machining data for a tool electrode.

• 화약ㆍ발파
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• 제40권1호
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• pp.17-28
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• 2022

고전압 방전에 의한 파분쇄기술 중 ED(Electrical pulse Disintegration)는 고체 내 절연파괴를 유도하여 고체 내 취약한 경계면을 분리하여 유가자원을 분리·회수하는 고효율 자원처리 기술로 알려져 있다. 본 연구에서는 고전압 방전에 의하여 고체 내 발생한 충격파가 황화광물 내 존재하는 아연광물의 단체분리특성을 분석하기 위하여, ED분쇄실험과 기계식 분쇄실험을 수행하고 분쇄산물에 대한 SEM-BSE 분석과 Microfocus X-Ray CT 분석을 수행하여 단체분리도를 비교하였다.

• 한국정밀공학회지
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• 제17권1호
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• pp.27-33
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• 2000

This paper presents a method for determining machining parameters in 3-dimentional electrical discharge machining(EDM). The parameters are the peak value of currents, the pulse-on time, and the pulse-off time. It is known that they influence the performance of EDM more than the other else. The parameters are determined from the discharge area between a tool electrode and a work piece. The discharge area is directly influenced by the geometry of a tool surface and the tool discharge position. The discharge area on a tool discharge position is calculated from intersection curves between the tool surface and a horizontal plane. The grid search method is applied to determine the intersection curves. An example is introduced to show that the machining parameters are obtained from the surface geometry of a tool electrode.

• Journal of Magnetics
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• 제16권3호
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• pp.234-239
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• 2011

Transcranial magnetic stimulation utilizes the method of controlling applied time and changing pulse by output pulse through power density control for diagnosis purposes. Transcranial magnetic stimulation can also be used in cases where diagnosis and treatment are difficult since output pulse shape can be changed. As intensity, pulse range, and pulse shape of the stimulation pulse must be changed according to lesion, the existing sine wave-shaped stimulation treatment pulse poses limitations in achieving various treatments and diagnosis. This study actualized a new method of transcranial magnetic stimulation that applies a 3 Stage 2 Switch( power semiconductor 2EA) for controlling pulse repetition rate by achieving numerous switching control of stimulation coil. Intensity, pulse range, and pulse shape of output can be freely changed to transform various treatment pulses in order to overcome limitations in stimulation treatment presented by the previous sine wave pulse shape. The method of freely changing pulse range by using 3 Stage 2 Switch discharge method is proposed. Pulse shape, composed of various pulse ranges, was created by grafting PFN (Pulsed Forming Network) through AVR AT80S8535 one-chip microprocessor technology, and application in transcranial magnetic stimulation was achieved to study the output characteristics of stimulation treatment pulse according to delaying time of the trigger signal applied in section switch.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.29-33
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• 2002

Period which does an electric condition of panel in reset in the driving method of PDP is reset period. This research experimentally analyzed the priming discharge characteristic of reset period. The amount of wall charge and the accumulation time accumulated by priming discharge are unrelated to width of priming pulse. And, self-erase discharge has the relation in the amount of wall charge by priming discharge. Then, it relates also to space charge generated by priming discharge. Moreover, space charge which helps self-erase discharge exists to about 22$mutextrm{s}$ after generating priming discharge. And, it is suitable within 12$mutextrm{s}$ of priming pulse width for efficient reset.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.827-831
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• 1997

Conductive veramic matrix composite(CMC) workpiece of TiC 33%/Al /sab 2/O /sab 3/ 66% Y /sab 2/ O /sab 3/ was machined by die sinking electrical discharge machining(EDM) according to different pulse duration and suty factor for reverse polarity of electrode. Material removal rate(MRR) was examined by process under various operating conditions. The surface morphology was evaluated by surface roughness values and scanning electron microscopy(SEM) research. The more MRR was obtained according to increase pulse duration and duty factor. Also the maximum surface roughness(Rmax) of EDMed surface was slightly changed with increased pulse duration and duty factor. The SEM photographs of EDMed surface showed wide recast wide recast distribution region of melting materials in purse duration 0.130(ms) than 0.048(ms).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1781-1783
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• 1996

Recently, the necessity of establishing the way to diagnose the aging of insulation materials and to predict of insulation breakdown become important. The purpose of our work are to investigate the treeing phenomena with a artificial needle shape void by the charge of partial discharge and acoustic emission pulse in each phase angle area at the same time. We have analyzed the ${\Phi}-Q-n$ pattern and the insulation diagnosis of the samples using statistic operators such as charge magnitude and A.E pulse factor, skweness, kurtosis, G,C. Therefore, the relation between the charge of partial discharge and A.E pulse will be helpful and efficient to predict the breakdown just before the breakdown occure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1830-1833
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• 2002

We measured 3-dimensional temporal behavior of the light emitted from AC plasma display panel(PDP) at various auxiliary voltage pulse width supplied to the address electrode in sustain period using scanned point detecting system. In the case of applying an auxiliary address voltage pulse, the light emission starts at the inner edges of the cathode so the larger discharge volume toward address electrode can be obtained compared with the normal sustain discharge. Especially, when the auxiliary voltage pulse width is the $2{\mu}s$, the maximum luminance and long emission time can be obtained.