• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.3
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• pp.200-208
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• 1999

In this paper, the corona discharge is analyzed by Finite Element Method(FEM) combined with Flux-corrected Transport(FCT) algorithm. In the previous papers, Finite Difference Method(FDM) combined with FCT was used. Usually in the FDM, the regionof interest is discretized with structured grids. But to refine local regions with same resolution, much more grids are required for the structured grids than for unstructured grids than for unstructured grids. Therefore, we propose the FEM-FCT method to simulate the corona discharge. The proposed method has good flexibility in model shape and can reduce the computational cost by the local refinement where the physical quantities have steep gradients. Using the proposed method, we study the streamer growth of parallel plate electrodes which is initiated by the low and high perturbation density. We find that the varying the initial density of perturbation has very little effect on the streamer propagation. And the corona discharge of the rod-to-plane electrode is simulated. On the surface of the rod electrode, the high concentration of the electric field gives rise to many number of streamer seeds. The strong axial streamer propagate to the plane electrode. The weaker non-axial streamer repel each other and stop growing more. The results are very similar to those of the papers which used the FDM-FCT method on structured grids. Thus we can conclude that the proposed FEM-FCT method is more efficient than the conventional FDM-FCT method by virtue of the reduction in computational grids number.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.74-80
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• 2003

Ionic wind is produced by a corona discharge when a DC high voltage is applied across the point-to-plane gap geometry. The corona discharge phenomena have been investigated in several beneficial application fields such as electrostatic cooling, ozone generation, electrostatic precipitation and electrostatic spraying. Recently ionic wind might be used in aerodynamic, for example, heat transfer, airflow modification, and etc. In this work, in order to analyze the control behavior of the velocity and amount of ionic wind produced by the positive DC corona discharges. The ionic wind velocity was measured as a function of the applied voltage, diameter of the punched hole on plate electrode and separation between the point-to-plate electrodes. As a results, the airflow is generated from the tip of needle to the plate electrode in the needle-to-punched-plate electrode systems. The ionic wind velocity is linearly increased with an increase in applied voltage and ranges from 1 to 3 m/sec at the locations of 100-200 mm from the punched-plate.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.4
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• pp.475-483
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• 1999

A lab-scale test was carried out to study the reduction of electrical energy consumption in the pulsed corona discharge process for nitrogen oxides removal. The experiment was mainly focused on 1) the activation of pollution removal reactions by chemical additives and 2) the optimization of electrical circuit for the efficient energy transfer from the power supply to the corona reactor. Hydrocarbon chemical additives used in the experiment are thought to be responsible for the enhancement of the NO conversion through the chain reactions of free radicals such as, R, RCO, and RO. Electrical energy consumption per converted NO molecule has a minimum value of 17 eV when pentanol is injected. When ethylene and propylene are injected, 30 eV and 22 eV of electrical energy consumption is required for the conversion of NO molecule respectively. The ratio of the pulse forming capacitance$(C_e)$ to the reactor capacitance$(C_R)$ plays an important role in the energy transfer efficiency to the reactor. Maximum energy transfer efficiency of approximately 72% could be obtained by using the pulse forming capacitance which is 3.4 times larger than the reactor capacitance, and also the maximum NO conversion efficiency was observed with the same condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.35-39
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• 2003

An ageing characteristics of RTV coating materials by corona discharge have been studied. The recovery of a hydrophobicity of RTV coating materials with the thickness of $300{\mu}m$ was in identical with a bulk silicone materials. The hydrophobicity of RTV coating materials has been almost lost when its were discharged during 40 seconds by corona with 10kV, and recovered after about 45 hours. But the resistivity of RTV coating materials has not been recovered after 45 hours, even though after 80 hours the 95% of initiation resistivity value has been recovered. There was no critical compounds(such as Si and Al) changes on RTV surfaces by the corona discharge treatment until 100 seconds. In the test of arc erosion, it was seen that the coating sample with silicone rubber as a base material have more longer bum-out time than other samples with FRP or glass base.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.504-508
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• 1995

The purpose of this research is to study on characteristics of corona ignitor which was designed for ignition of plasma, used at hard coating, surface treatment and thin film preparation, at high pressure. Corona ignitor composed of hollow type inner electrode and ring type external electrode. Though corona voltage increased with increasing distance between electrodes, corona discharge can be controlled stably. The gas flow in hollow type inner electrode and the construction between electrodes affect a length of corona flame and corona phenomenon. It is possible to ignite the . plasma, usually generated at low pressure(10 Torr), at high pressure(100 Torr) by corona ignitor.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.8
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• pp.394-400
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• 2001

This paper describes an application of the on line partial discharge measurement method in operating transformer. In the operating transformer, the partial discharge signal may be superimposed by radio intereference voltage(RIV) and pulse shaped noise signals generated by external corona. The partial discharge quantity showed about 3,800pC due to very high sinusoidal interferences at the measuring impedance terminal of the transformer bushing tap. In order to reject these noises, this paper applied RIV filter, band-pass filters and noise gating method. The resulting measuring sensitivity was improved from 3,800pC to 160pC.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.7
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• pp.579-587
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• 2001

This study investigates particle collection characteristics of a cylindrical electrostatic precipitator. Experimental work has been made for the submicron particles. The effects of polarity of discharge electrode wire, particle diameter, gas velocity, gas temperature, and specific corona power on the particle collection efficiency are investigated. The efficiency of negative corona is higher than that of positive corona. as the particle diameter increases, the efficiency is decreased when the diameter is in the range of 0.02-0.6 micron, but is increased for the nanometer particles with diameter smaller than 0.02 micron. The efficiency is increased with increase of specific corona power. As the gas temperature increases, overall collection efficiency is increased for a negative corona, but is deceased for a positive corona.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.239-246
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• 2014

Incineration is conceptually sound as a waste treatment technology. There is, however, concern over its emissions when it is improperly designed and operated. An electrostatic precipitator is one of the most commonly used devices to control particulate emissions from boilers, incinerators and some other industrial processes. In this work, a modular electrostatic precipitator with sizing of $1m{\times}1m{\times}1m$ was developed for removal of particulate matter from the exhaust gases of a small waste incinerator. Its design was based on a simple wire-and-plate concept. The corona discharge wires were connected to a positive high-voltage pulse generator, while the collection plates were grounded. The high-voltage pulse generator was used to produce the corona discharge field between the individual discharge wire and the collection plate. The particulate-laden exhaust gas flow was directed across the corona discharge field. The charged particles were deflected outward and collected on the plate. The collection efficiency was evaluated as a mass loading ratio between the difference at the inlet and the outlet to the particulate loading at the inlet of the precipitator. The collection efficiency of this modular electrostatic precipitator design was approximately 80 %.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.35-40
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• 2012

In this study, the ultraviolet (UV) intensity of polymer insulator was measured using the Anti-Reflective (AR) coating lens on the occurrence of corona discharge. The UV intensity was compared before and after the AR coating. Under the 200-260[nm] of UV lens, the reflection rate before AR coating was 7.5~5.5[%] with 85-89[%] of transmission rate. After AR coating, however, the reflection rate decreased to 1.3~1.22[%] with improved transmission (97.4~97.6[%]). Then, the UV intensity by distance was measured in the polymer insulator. According to the measurement, the UV intensity increased 6.5 times at 37.5[%] of Vm/Vbd with 5[m] of distance. As distance increased, the growth rate declined. As high voltage increased, in addition, AR coating was less effective due to the count error caused by the UV sensor pulse signal overlap. Therefore, it appears that it would be more effective to detect corona discharge with 5[m] or less of distance at diagnosis of power facilities by AR coating and UV sensor sensitivity.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.12
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• pp.77-82
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• 2015

Ozone is a powerful disinfectant and oxidizing agent, and it is used in a wide range of applications, such as waste water treatment, food processing, etc.. There is also a great potential of using ozone in new emerging medical applications, such as ozone dentistry and ozone oxygen therapy. For these purposes, simple, small, compact and efficient sources of ozone are needed. In this study, in order to increase the current-voltage range of the discharge and to avoid the overheating of the gas in the ozonizer we suggested ozonizer of injection needle and plate electrode type(INP Type) with the gas through the needle. A ozonizer of INP type have been investigated by focusing on ozone concentration and yield according to flow rates and Gap of two electrodes. The results of studies of ozone production for DC corona discharge in oxygen at atmospheric pressure about the ozonizer of INP type. The ozone concentration and the generation yield increased as the gap of two electrodes and gas flow were decreased. Also, when the gap of two electrodes and gas flow with no change, the ozone concentration and generation yield each have variation of direct proportion and inverse proportion with discharge voltage.