• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.1
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• pp.67-74
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• 2000

This paper presents the analysis of partial discharge signals according to the particle states in GIS, for preventing the insulation failure and recognizing the particle states. In this paper, four states of particle (particle on electrode, particle on enclosure, particle on spacer and crossing particle) were simulated. And $\Phi$-Q-N distribution of partial discharge signals was analyzed and the statistical operator of the $\Phi$-Q distribution was analyzed. As a result, it was found that the states of particle were distinguished by analysis of the $\Phi$-Q-N distribution and the statistical operator of the $\Phi$-Q distribution.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.6
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• pp.67-74
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• 2005

Grounding insures a reference potential point for electric devices and also provides a low resistance path for fault currents in the earth. The ground impedance as a function of frequency is necessary for determining its performance since fault currents could contain a wide range of frequencies. In this paper, the ground impedance of Magic rods which are commercially available has been measured in frequency ranging from 0[Hz] up to 100[kHz] and an equivalent circuit model, transfer function model of the ground impedance are identified from the measured values.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.1
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• pp.8-12
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• 2002

In this paper, we studied a flat fluorescent lamp with high luminance for LCD backlighting. The lamps have simple structures with ITO glass, insulator layer, phosphor layer, electrode layer and gas gap. The firing voltage was decreased with increasing the frequency. It was considered that this tendency was resulted from the space charge effect due to Xe and Ar positive ions trapped in gas gap. Decrease of uniform voltage at higher drive frequency is due to the remaining space charges which are produced by preceding period. As a result, luminance of 2700[cd/m$^2$] and maximum luminous efficiency of 51[m/W] were obtained with luminance uniformity of 96[%] in operation(700[V$\_$rms/], 80[kHz].

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.112-117
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• 2004

This paper describes the analysis of the UHF signal characteristics due to the partial discharge sources which can exist in a GIS. For the experiment, a model GIS was made and 5 types of discharge source were created as follows; corona discharge, surface discharge, void discharge, discharge due to free particle, discharge from floating electrode. The frequency spectra and the phase characteristics of UHF signals were induced by UHF signal analysis. The results were quantified to systematically adapt to analyze the PD sources in the GIS and utilized as algorithm data based on the neural network for Back-Propagation Algorithm with a multi-layer structure. The perception rate of the constructed algorithm showed approximately 94[%] and 82[%] in learning and testing data, respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.42-47
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• 2004

This research has improved the problem of discharge AND gate PDP proposed before. The polarity of the DC discharge which composes AND gate is reversely designed and the cross talk problem to the adjacent scanning electrode has been improved. The AND gate proposed before operated by using non-linearity of the discharge by the space charge. In this research, new discharge NOT logic in which it was used that an applied voltage changed with the discharge circuit was added to AND gate. AND gate came to operate more stably. A selective address was able to be discharged with four horizontal scanning electrodes from the experiment result. The operation margin of the AND gate discharge obtained 34V and of the address discharge obtained 70V.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.4
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• pp.97-103
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• 2011

The most important object of grounding systems is to protect human being from electric shock. Touch and step voltages are measured to evaluate the performances of grounding systems. Dangerous voltages have been largely studied by the power frequency fault currents, on the other hand, the ground current containing the high frequency components and surge currents haven't been considered. Many attempts about the grounding impedances reported in these days show that the performance of the grounding systems in high frequency range is very different with the ground resistance. It is necessary to analyze the dangerous voltages formed by the ground currents containing high frequency components. In this paper, the ground surface potential rises near the vertical and horizontal grounding electrodes are measured at the frequency of 100[Hz], 30[kHz], and 100[kHz]. Dangerous voltages are investigated with the frequency-dependent grounding impedance. As a result, the ground surface potential rise is increased as the grounding impedance increases. Touch and step voltages near the grounding electrode whose impedance increases with the frequency are sharply raised.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.11
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• pp.104-108
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• 2012

Flexible organic thin film solar cell device with Bulk Hetero-Junction (BHJ) structure was fabricated with blended conjugated polymer of PCDTBT : $PC_{71}BM$ as active layer. Surface of ITO anode for the organic solar cell device was treated with ozone. The organic solar cell device with bare ITO showed short circuit current density ($J_{sc}$) of $8.2mA/cm^2$, open-circuit voltage ($V_{oc}$) of 0.73V, fill factor (FF) of 0.36, and power conversion efficiency (PCE) of 2.16%, respectively. The organic solar cell device with ozone treated ITO anode revealed distinctively improved performance parameters:$J_{sc}$ of $9.8mA/cm^2$, $V_{oc}$ of 0.82V, FF of 0.43, PCE(${\eta}$) of 3.42%.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.153-157
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• 2009

A Highly efficient Mercury-free Flat Fluorescent Lamp (MFFL) with dielectric barrier Xe gas discharge was developed for an alternative of conventional line-type Cold Cathode Fluorescent Lamps (CCFLs) which shows a wide voltage margin and a stable discharge operation for diffuse glow discharge with an application of a auxiliary electrode. Electro-optic characteristics of the MFFL were examined through the changes in ambient temperature, total pressure and Xe partial pressure. the single cell is expanded into a multi-structured configuration to realize a large sized lamp by a simple repetition of the single cells, and a new driving scheme is proposed for an adaptive brightness control using dual auxiliary electrodes and bi-polar drive scheme. In addition, interesting application of this ultra high luminance flat lamp by the optimization of the gas condition and the pattern of the rear phosphor layer is suggested as a good alternative of daylight lamp source

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.2
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• pp.76-83
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• 2014

This paper deals with the numerical method of calculating the frequency-dependent impedances of grounding electrodes. The proposed electromagnetic field approach is based on the solutions to Maxwell's equations obtained from the method of moment in the frequency domain. In order to evaluate the quality of the proposed simulation method, the frequency-dependent impedances of horizontally-buried ground electrodes were presented. The program for calculating the current distributions and impedances of grounding electrodes was implemented in MATLAB. The grounding impedances of two 10m and 50m long horizontal ground electrodes were measured and simulated in the frequency range from 100Hz to 10MHz for easy analysis and comparison. Also the simulated results were compared with those calculated from a sophisticated computer program CDEGS (HIFREQ module). As a result, the resultant results of frequency-dependent impedances obtained by using the numerical simulation method proposed in this work are in good agreement with experimental data. The validity of the approach techniques was confirmed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.19-26
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• 2006

The ccrf-discharge has in comparison with the hollow-cathode discharge and DC-discharge some advantages: Simple design of the tube and homogeneous plasma. The ccrf-discharge was researched with the goal, to use on the excitation of the gas laser. In this work a rf-exciting system was planned and developed. With it a homogeneous discharge was produced in the cw operation. To supply the rf-power with the frequency 13.56[MHz] effectively in the discharge, laser tube were used with inner diameter of 5[mm] and the specially developed rf-electrodes. A matching circuit was composed also. Thereby the impedance of the discharge tube was adjusted to the 50[$\Omega$] output resistance of the rf-source.