• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.52-57
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• 2002

High temperature superconductors can only be applied against an engineering specification that has to be determined for each particular application form the design requirements for economic viability and for operation margins in service. However, in order to realize the HTS transformer, it is necessary to establish the high voltage insulation technique in cryogenic temperature. Therefore, the composite insulation of double pancake coil type transformer are described and ac breakdown voltage characteristics of liquid nitrogen($LN_{2}$) under HITS pancake coil electrode made by Bi-2223/Ag are studied. Breakdown in $LN_{2}$ is dominated electrode shape and distance. And we investigated AC breakdown properties of $LN_{2}$ and complex conition of cryogenic gaseous nitrogen($CGN_{2}$) obove a $LN_{2}$ surface. Also, the surface voltage of GFRP was measured as a function of thickness and electrode distance in $LN_{2}$ and complex condition of $CGN_{2}$ above a $LN_{2}$ surface. This research presented information of electrical insulation design for double pancake coil type HTS transformer.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.133-134
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• 2022

This study proposed vision artificial intelligence-based automated supervision technology for external insulation and finishing system, and basic research was conducted for it. The automated supervision technology proposed in this study consists of the object detection model (YOLOv5) and the part that derives necessary information based on the object detection result and then determines whether the external insulation-related adhesion regulations are complied with. As a result of a test, the judgement accuracy of the proposed model showed about 70%. The results of this study are expected to contribute to securing the external insulation quality and further contributing to the realization of energy-saving eco-friendly buildings. As further research, it is necessary to develop a technology that can improve the accuracy of the object detection model by supplementing the number of data for model training and determine additional related regulations such as the adhesive area ratio.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1107-1113
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• 2015

Test temperature is an important factor affecting the measurement results of dielectric response of field power transformers. In order to better apply the polarization and depolarization current (PDC) to the condition monitoring of oil-paper insulation system in power transformers, the influences and elimination method of test temperature on PDC characteristic spectroscopy (PDC-CS) were investigated. Firstly, the experimental winding sample was measured by PDC method at different test temperatures, then the PDC-CS was obtained from the measurement results and its changing rules were discussed, which show that the PDC-CS appears a horizontal mobility with the rise of temperature. Based on the rules, the “time temperature shift technique” was introduced to eliminate the influence of test temperature. It is shown that the PDC-CS at different test temperatures can be converted to the same reference temperature coincident with each other.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1912-1914
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• 2000

This is the first report of a series of field test result of large high voltage generator & motors. Major specimens were 6.6/13.2kV class hydroric power & pump motor that was installed and operated for public water service by KOWACO(KOrea WAter resources COperation). The capacity of specimen gene rater & motors were in range of several hundred kVA$\sim$50MVA. Until now, we get the 100 field test result by testing technique discribed in IEEE standards and Discharge map technique from Japanse manufactures. The test result was varied very wide range, and there was a tendency according to insulation material and manufacture.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.588-593
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• 2011

The airpollutant may accelerate degradation of power line facilities, and may reduce the life of the electric facilities. In case of korea, there are a tendency that the density of air pollution may be increased by industrial development. while lack of research activity and establishment of a countermeasure on this issue. Recently the occurrence of electricity failure have been reduced on the power transmission and distribution lines. but the occurrence of electricity failure by insulator itself has been increased. It means that we should have develop more clear technique for detection of the wrong insulator. In this study to provide a method for detection of the insulator failure or effective management of the troubled insulator, we analyze the chemical composition of the insulator which used on power distribution line at the sea side locations. To define the relation between insulation and corona intensity, we design and develop an corona detector. We define the variation of insulation by pollution changes on the insulator and verify quantitative relation between corona and insulations using the corona detector.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.46-49
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• 1994

In order to investigate possibility of CV cable diagnosis technique, residual insulation characteristics of .long - term serviced 0.6 kV CV Cable are examined by DC leakage current residual voltage tensile strength, cross1inking density and AC & impulse breakdown. Also effect of cable structure and water tree are reported

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.403-405
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• 2001

This paper presents the detection method of partial discharge in metal clad switchgear(MCS) using electromagnetic technique. Two antennas are located in the inside and outside of the MCS, and electromagnetic waves detected by these antennas are analyzed and compared by FFT method in order to identify an insulation abnormality. As a result of the experiment by the proposed method, we show the detection possibility for partial discharge in the MCS. The proposed method is expected to apply to insulation condition observation and an accident prevention in the MCS effectively.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1727-1729
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• 2001

Partial discharge testing are rapidly becoming the most powerful tool to assess the condition of high voltage generator and motor stator windings. Recently, on-line monitoring scheme with trending technique is widely applied in insulation diagnosis. This paper describes the on-line partial discharge detecting techniques in the high voltage motor stator windings. Also, on-line monitoring system for an insulation diagnosis are proposed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.11-16
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• 2005

This study is for the insulation construction of inner wall in a bathroom facing on the outside in the housings. This new dry construction method can be constructed by a dry panel which is bonded tiles on the extruded and expanded poly-ethylene panel in stead of the existing wet construction method. Compared to the existing method, this panel is light movably and is constructed simply. These representative construction merits are getting wide span in a bath due to reducing wall thickness and saving construction period.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.296-297
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• 2011

A series of thermogravimetric analysis tests were conducted to predict the lifetime of the PTFE electrical insulation material. The prepared PTFE samples were heated from $25^{\circ}C$ to $700^{\circ}C$ at different heating rates. The kinetic energy of the PTFE was calculated from the logarithmic heating rate versus reciprocal temperature curves at constant conversion levels. Also, the lifetime of the PTFE for a given operating temperature can be predicted using the relationship between the activation energy and the estimated lifetime proposed by Toop.