• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.704-707
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• 1999

Partial discharge(PD) in air insulated electric power systems is responsible for considerable power lossesfrom high voltage transmission lines. PD in air often leads to deterioration of insulation by the combined action of the discharge ions bombarding the surface and the action of chemical compounds that are formed by the discharge and may give rise to interference in ommunication systems. PD can indicate incipient failure. Thus understanding and classification of PD in air is very important to discern source of PD. In this paper, we investigated PD in air by using statical method. We classified air discharge with corona, surface discharge and cavity discharge by source of discharge. we used the mean pulse-height phase distribution $H_{qmean}(\psi)$, the max pulse-height phase distribution $H_{qmax}(\psi)$ , the pulse count phase distribution $H_n(\psi)$ and the max pulse height vs. repetition rate $H_{q}(n)$ for analysis PD pattern. We used statistical operators, such as skewness(S+. S-1, kurtosis(K+, K-), mean phase(AP+. AP-), cross-correlation factor(CC) and asymmetry from the distribution.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.13-19
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• 2007

This study relates to a new high-speed drive method for the full-HD PDP with 1080 horizontal scanning lines. The characteristics of the new drive method is evaluated considering the characteristics of the display discharge by the high-speed addressing. In this drive method, if the width of the address pulse narrows, the relati0[V]e discharge strength and the discharge time lag of the first display discharge are received the influence of it. Though the change in the applied position of the address pulse is unrelated to the discharge strength, it influences at the discharge time lag. However, the stable display discharges can be induced regardless of the address pulse position and width if the address pulse position is within [$6{\mu}s$] and the width is up to [$0.7{\mu}s$]. From the experiments, it has been understood that the high-speed drive technique with the address pulse of narrow width is sensitively influenced by the space charge because of the insufficiency of wall charge.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1237-1240
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• 2005

The effects of various sustain waveforms on the discharge characteristics, such as discharge current waveform, IR waveform, luminance, luminous efficiency, power consumption, and static margin are investigated under high Xe (20%) gas mixture at 200 kHz. The four types of sustain waveforms, such as non-overlapped sustain waveform without auxiliary pulse, non-overlapped sustain waveform with auxiliary pulse, overlapped sustain waveform without auxiliary pulse, overlapped sustain waveform with auxiliary pulse, are examined intensively. As a result, the overlapped sustain waveform with auxiliary pulse shows the best discharge characteristics under high Xe (20%) gas mixture at 200 kHz.

• Electrical & Electronic Materials
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• v.10 no.3
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• pp.247-254
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• 1997

Internal voids in insulators give rise to partial discharge, which causes a local breakdown and even entire insulation breakdown. 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 an artificial needle shaped void by the charge of discharge and acoustic emission pulse in each phase angle area at the same time. We analyzed the .PHI.-QA-t pattern and .PHI.-AEA-t pattern using statistic operators such as pulse magnitude, pulse number, skewness, kurtosis. Therefore, the relation between the charge of discharge and acoustic emission pulse will be helpful to predict the breakdown just before the breakdown occur.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.609-612
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• 2002

A new reset waveform is proposed for reducing the reset period. A square pulse is applied to the address electrode while reset pulse ramps and before a discharge between the sustain electrodes occurs. The square pulse induces a discharge between the address electrode and the X electrode, and the induced wall charge is opposite to the applied ramp pulse. Thus, the next discharge between the sustain electrodes becomes weaker. The weaker discharge lowers background luminance and improves contrast ratio. Thus, the new reset waveform can reduce ramp up time in the ramp reset waveform The experimental results show that the ramp up time can be reduced by about 90% compared with the conventional ramp reset waveform.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.528-533
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• 2006

Electrical discharges may occur in gas, liquid as well as solid insulating materials. This paper describes the investigation results on the discharges in air, silicone oil and low density polyethylene (LDPE) using needle plane electrode system under AC voltage of 50 Hz. The experimental results showed that for discharge in air (corona), discharge pulses were concentrated around the peak of applied voltage at negative half cycle. For silicone oil positive as well as negative discharges were observed which concentrated around the peak of applied voltage. The positive pulse number was smaller but the magnitude was higher than that of negative discharge. Discharges in void took place at wider range of phase of applied voltage. The unbalance in pulse number and magnitude similar to that of oil discharges were observed. For electrical treeing in LDPE, the discharges were spread before the zero cross of the applied voltage up to the peak at both positive and negative half cycles. The discharge pulse sequence analysis indicated that the PD occurrence in air, oil and void were strongly affected by the magnitude of applied voltage. However, for electrical treeing it was observed that the discharge occurrence was strongly affected by the time derivative of the applied voltage (dv/dt).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.42-45
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• 1994

In this paper, we will report on the effect of the pointed end shape of an electrode, discharge energy, pulse width and discharge current on machining characteristics. The results obtained are as tollows: 1)As the discharge Energy increases, the diameter and the depth of the discharged crater becomes larger and deeper. 2) The discharge energy is not constant during discharge but varies depending on the pointed end shape of th8 electrode. 3) The shape of crater depends on the pulse width and discharge current.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.68-74
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• 2007

For carnation productivity improvement, compact-low cost discharge lamp type ozonizer using pulse power source is designed and manufactured. This paper describes the discharge characteristics and the ozone generation characteristics with variation of the output voltage of pulse power source, the quantity of flowing air and the operating number of ozonizer. The important conclusions are as follows. The discharge voltage and current values are proportional to the output voltage of pulse power source. The ozone concentration and generation are proportional to the output voltage of pulse power source and the number of ozonizer. The maximum value of the ozone concentration and generation of the discharge lamp type ozonizer can be obtained 890[ppm] and 59.7[mg/h] respectively. In the carnation productivity house, when the discharge lamp type ozonizer is used the carnation is good quality in the uniformity of the carnation stalk thickness and increased the productivity through improvement of the air and the soil.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.5
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• pp.98-103
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• 2011

Recently, UV(ultra-violet rays) camera has attracted a great deal of interest from the view point of easy judgement in inspections and diagnoses of the safety of power equipment. Especilly, UV camera is applied the inspection of UV with corona discharge. One of the most important and difficult problems is the basic research of filter design, materials and corona discharge. In this paper, we will report on the UV generation, corona pulse count and the polarity effect of positive and negative DC surface discharge in air. Also, corona discharge characteristics are analyzed using prototype UV camera of Korea. UV generation and corona pulse count due to surface discharge in positive needle is higher than that of negative needle.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.2
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• pp.136-141
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• 2021

Heating cables, widely used in office buildings, factories, streets and railways, deteriorate in electrical insulation during operation. The insulation deterioration of heating cables leads to electric discharges that can cause electrical fires. With this background, this paper dealt with a condition monitoring technique for heating cables by the analysis of discharge signals to prevent electrical fires. Insulation deterioration was simulated using an arc generator specified in UL1699 under AC operation, and the characteristic and propagation of discharge signals were analyzed on a 100 meter-long heating cable. Discharge signals produced by insulation deterioration were detected as a voltage pulse because they are as small as a few mV and they are attenuated through propagation path. The frequency spectrum of discharge signals mainly existed in the range from 70 kHz to 110 kHz, and the maximum attenuation of the signal was 84.8% at 100 meters away from the discharge point. Based on the experimental results, a monitoring device, which is composed of a high pass filter with the cut-off frequency of 70 kHz, a comparator, a wave shaper and a microprocessor, was designed and fabricated. Also, an algorithm was designed to discriminate the discharge signal in the presence of noise, compared with the pulse repetition period and the number of pulse counts per 100ms. In the experiment, the result showed that the prototype monitoring device could detect and discriminate the discharge signals produced at every discharge point on a heating cable.