• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1598-1600
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• 1998

When dielectric surface electric field exceed any electric field strength on air, corona discharge is occurred from the dielectric surface. This paper presents corona discharge phenomena on the dielectric in high field were studied under application of ${\pm}DC$ voltage, constitute of the point to plane 20mm gap. The results obtained in experimental are summarized as follow :(1) Corona pulse is appeared periodically after first corona pulse is occurred and the number of corona pulse increases with the instantaneous applied voltage but peak value is not changed greatly.(2)Applied voltage to beccrite and characteristics and peak value of current are almost a straight line. That kind of tendency accorded with characteristics of beccrite resistance.(3)In case of Positive corona, Positive streamers, were progressed greatly to plane electrodes but In case of negative corona, negative streamers smaller than that of Positive corona.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.9
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• pp.651-654
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• 1987

There are a number of small scale application fields of ozone, such as food conservation and/or storage in refrigerators, containers and storage rooms, deodorization in the production and living areas, protection against biohazards, bleaching of fabrics, etc. For these applications, miniaturization, ozone controllability and costdown of the ozonizer are the most essential points, whereas power efficiency is the most imporant factor in the case of a large scale ozonizer used in various industrial applications. It has been developed a novel sawtooth-to-cylinder type micro-ozonizer meeting above the three points by using a negative pulse corona discharge. As a result of the observations of pulse coronas affecting ozone generation, it is found that the maximum ozone concentration is generated at the pulse streamer coronas in both positive and negative case. The ozone concentration (20ppm/2l/min) generated by the negative pulse corona is about 2 times higher than that of the positive pulse corona, and could be controllable linearly by adjusting the dc input voltage of the [supply-inth ] cinventional small scale ozonizers. As a result, the present ozonizer is also very good to be used as a micro-ozonizer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.11
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• pp.74-81
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• 2015

In the measurement of atmospheric static electric field, it is important to know characteristics of corona discharges caused at the tip of test electrode. This paper presents the fundamental data of DC corona discharges that occurred at the tip of a needle-shaped electrode placed in the homogeneous background electric field which simulates the atmospheric static field under thundercloud. The major characteristics of interest for this purpose are the polarity effect of corona discharges and the magnitudes and time intervals of corona current pulses. The experimental set-up consists of the plate-to-plate configuration with a needle-shaped protrusion, DC power supply, and voltage and current measuring devices. As a result of experiments, the polarity dependence of corona pulses is significantly pronounced. The time intervals between successive corona pulses in the negative polarity is much longer than those in the positive polarity. The time intervals for both polarities is drastically decreased as the applied electric field is increased. Also the magnitudes of the positive corona pulses are slightly changed with an increase in applied electric field, but those of the negative corona pulses are linearly increased with increasing the applied electric fields.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.11
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• pp.508-514
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• 2005

In this paper, it was investigated the characteristics of PD(partial discharge) pulse shapes in oil and the possibility of TF(Time-Frequency) analysis for the discrimination of air corona in on-site PD measurement of oil transformers. For the purpose, single and multiple discharges combined with oil discharges and air corona were generated and measured by use of artificial models through the HFPD pulse detector and the oscilloscope. PD pulse shapes were different according to the type of defects, especially including air corona- pulses. Also, through the TF analysis, data clusters could be classified each other in the TF Map, even in the case of multiple discharges. Therefore, it is known that TF analysis could be aprlied for the improvement of on-site PD measurement in oil transformers.

• 한국연소학회:학술대회논문집
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• 1997.06a
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• pp.69-76
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• 1997

Industrial-scale pulse corona process to remove $SO_2$ and $NO_x$ simultaneously from combustion flue gas has been studied. The pilot plant built in the present study treats 2,000 $Nm^3$/hr of flue gas from a boiler. The geometry of the pulse corona reactor is similar to that of an electrostatic precipitator commonly used in industry, A thyratron switch and magnetic pulse compressors, which can generate up to 130 kV of peak pulse voltage and up to 30 kW of average pulse power, have been used to produce pulsed corona. The removal efficiencies of $S0_2$ and $NO_x$ with the present process are maximum of 95 % and 85 %, respectively. Electrical power consumption to produce the pulsed corona, which has been one of the major difficulties to apply this process to industry, has been evaluated in the present study. The results showed that the power consumption can be reduced significantly by simultaneous addition of hydrocarbon injection and heterogeneous phase reactions to the process.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.5
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• pp.91-96
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• 2012

The surface of bushing is contaminated with rain, dust, salt and others. A bushing with contaminations in air is serious problem in insulation. Therefore, it is important to understand the inspection and diagnoses of the safety. The ultra-violet rays(UV) camera has attracted interest from the view point of easy judgement. In this paper, we will report on the corona discharge characteristics of surface flashover model with contaminations in air. Also, UV images of discharge and corona pulse count in air are analyzed using prototype UV camera of Korea and a UV sensor with an optic lens. These results are studied at both AC and DC voltage under a non-uniform field.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1059-1064
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• 2001

This study Investigates the effect of the wave form of pulse energization on the collection characteristics of a wide plate spacing electrostatic precipitator. For the semi-pulse energization, the peak current and voltage of the energization increases with increase of the pulse period, and the corona current increases, as pulse ratio decreases. For the micro-pulse energization, the corona current increases with increase of the pulse voltage. The collection efficiency of semi-pulse and micro-pulse energization is larger than that of DC charge.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.11
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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.

• 한국연소학회:학술대회논문집
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• 1999.10a
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• pp.117-128
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• 1999

The removal of nitrogen oxides(NOx) from $N_{2}/O_{2}$ gas using a pulsed corona discharge was investigated as a function of the reduced electric field(E/N) and the energy density(J/L). A kinetic model was developed to characterize the chemical reactions taking place in a pulsed corona discharge reactor. The model calculates the fractional concentrations of radical species at each pulse-on period and utilizes the radicals to remove NOx for the subsequent pulse-off period. Electron collision reaction data are calculated using ELENDIF program to solve Boltzmann equation for electron energy distribution function, and the subsequent chemical reactions are calculated using CHEMKIN-II program to solve stiff ODE(ordinary differential equation) problems for species concentrations. The corona discharge energy per pulse and the time-space averaged E/N were obtained by fitting the model to experimental data. The model calculation shows good agreement with the experimental data, and predicts the formation of other species such as $NO_{2}$, $O_{3}$ and $N_{2}O$.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1781-1783
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• 2004

Flue gas from fossil fuel combustion is the main source of air pollution. It is recognized that $SO_2$ and $NO_x$, (sum of NO and $NO_2$) react with $H_2O$ and $O_2$ in atmosphere and convert precursors of acid rain. Streamer corona process using pulse power is one of the effective methods to remove these gases from stack. For this, pulse generator with 160 kV of output peak voltage, 0.3 ${\mu}s$ of pulse width and 120Hz of pulse repetition rate is developed. This paper shows the pulse compression characteristics to obtain optimum parameters for basic system design.