• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.6
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• pp.474-480
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• 2012

Diagnostic tests were performed on two high voltage(HV) motor stator windings. These tests included the measurement of insulation resistance, polarization index, AC current, dissipation factor($tan{\delta}$) and partial discharge(PD) magnitude. Surface contamination of HV motor stator windings has an effect on the AC current and $tan{\delta}$. When the stator windings were finished cleaning and insulation reinforcement, the increase rate of AC current(${\Delta}I$) and dissipation factor(${\Delta}tan{\delta}$) were very small compared to those before cleaning. However, the PD magnitude remained the same. These tests show that cleaning and insulation reinforcement of HV motor stator windings can reduce the insulation failure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.379-382
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• 1999

In this paper, we investigated the characteristics of MgO thin film prepared by unbalanced magnetron sputtering(UBMS) in surface discharge type AC PDP The minimum discharge voltage is obtained for the sample of substrate bias voltage-10V. Moreover the anti-sputtering characteristics of MgO thin film by UBMS is improved about 40% than one of balanced magnetron sputtering(BMS)

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1491-1494
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• 2006

We report a method for reducing the address discharge delay. The address discharge delay was reduced when the MgO protective layer was made on the dielectric area which was made rough intentionally. The delay reduction was more pronounced in the formative delay.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.529-532
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• 2004

The spatio-temporal variation of Infra Red(IR) emission images were obtained from a real 3-dimensional discharge space of a surface discharge type, alternating current plasma display panel(AC PDP) cell with the Ne-Xe(4%) 400Torr gas mixture. IR emissions were observed in each period of the ADS(Address and Display Separation) driving scheme with ramp initializing waveform using an images intensified charge coupled device(ICCD) camera. The roles of each electrode were identified and it was compared with the results of the discharge simulation and of the wall charge distributions measured by the electro-optic technique.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.232-236
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• 2015

The electro-optical characteristics of several functional layers over the MgO protective layer were studied during the continuous discharge of an AC-PDP. In order to observe the degradation of each functional layer on the MgO protection layer, we measured the surface morphology, cathodoluminescence (CL) spectrum, the secondary electron emission coefficient (${\gamma}$) and the discharge characteristics after 500 hours of discharge during the operation of the AC-PDP.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.2
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• pp.61-67
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• 2003

To improve the luminance and luminous efficiency of a surface-discharge alternate current plasma display panel, we analyzed the sustain discharge characteristics as the voltage of the address electrode In the study. As the results, when the address voltage is a half of the sustain voltage in the sustain period, the luminance and luminance efficiency are the highest. The luminance efficiency increased about 16.2%~20.8% compared with the conventional type.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.106-112
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• 2010

In order to compete with other flat display devices such as Liquid Crystal Displays (LCDs) and organic light emitting diodes (OLEDs), Plasma Display Panels (PDPs) require to have high performances like high image quality, low power consumption and high speed driving. In this paper, Fe doped MgO protective layer was introduced for higher performance. Both the surface characteristics of the deposited thin films and the electro-optical properties of 4 inch test panels were investigated. It has been demonstrated experimentally that ac PDP with Fe doped MgO protective layer has lower discharge voltage than that of undoped MgO film, which corresponds to measured secondary electron emission coefficients. The crystallinity and surface roughness of thin films were determined by XRD patterns and AFM images. In addition, ac PDP with Fe doped MgO protective layer has improved address discharge time lag for high speed driving.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.4
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• pp.314-318
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• 2011

Recently, ultrasound, infrared detector, V-I characteristic, gas analysis, UV (ultra-violet rays) camera etc. is used as inspections and diagnoses of the safety of power equipment. Especially, UV camera have attracted a great deal of interest from the view point of easy judgement. UV camera is used corona discharge. One of the most important and difficult problems to be solved filer design, materials and corona discharge. This paper is studied on the temperature characteristics, UV generation and shape analysis and corona pulse count according to the electrode distance and applied voltage. Also, Corona discharge characteristics in air are analyzed using prototype UV camera of Korea. UV generation due to surface discharge of AC is higher than that of DC.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.2
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• pp.317-321
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• 2021

As the large-scale renewable energy power plant increases, the high-capacity and compact Energy Storage System (ESS) is required. However, this trend could reduce the insulation reliability of ESS. In this study, the surface flashover characteristics for four types of solid insulators are investigated in the uniform electric field with AC and Lightning Impulse (LI) voltage waveforms under various contamination levels. In addtion, insulator surfaces are compared based on the contact angle before and after surface flashover. The experimental results show that AC flashover voltage is dependent on the materials and the contamination level, but LI flashover voltage is only associated with the contamination level. Especially, AC flashover voltage of PC (PolyCarbonate) is higher than that of other insulators, which is associated with the unique and sequential creepage discharge propagation pattern of PC. The localized discharges on the surface of PC form corresponding tracking points. Then, the interconnected trackings result in the complete flashover. This flashover patterns degrade the surface of PC much more than that of epoxy and Bulk Molding Compoud (BMC). Thus, the contact angle of PC is significantly reduced compared to that of other insulators. The increased hydrophilicity in the surface of PC enhances the insulator surface conductivity.

• Journal of Electrical Engineering and Technology
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• v.10 no.2
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• pp.603-609
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• 2015

Dry air is an excellent alternative to $SF_6$ gas and is used as an insulation gas in Eco-friendly Gas Insulated Switchgears (EGISs), which has gained popularity in industry. Solid insulators in EGIS play an important role in electrical insulation. On the other hand, surface discharge can occur easily when solid insulators are used. This paper explored the surface discharge characteristics on the structure of three-layered laminated solid insulators to elevate the flashover voltage. A laminated solid insulator was inserted after the quasi-uniform electric field was formed in the test chamber. Dry air was then injected to set the internal pressure to 1 ~ 6 atm, and the AC voltage was applied. When identical solid insulators were stacked, the surface discharge characteristics were similar to those of a single solid insulator. On the other hand, the flashover voltage rose when the middle part was thicker and had lower permittivity than the top and bottom parts in the laminated solid insulator. Based on experimental results, when stacking a solid insulator in three layers, the middle part of the solid insulator should be at least four times as thick as the top and bottom parts and have lower permittivity than the others. In addition, the flashover voltage increased with increasing gas pressure on the surface of the laminated solid insulator due to the gas effect. This study may allow insulation design engineers to have useful information when using dry air for the insulation gas where the surface discharge can occur.