• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.190-191
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• 2006

In this paper, a method to assess the reliability of an insulating spacer used in gas insulated switchgear by electrical accelerated lifetime test is represented. And a test plan to assure the expected lifetime with 90 % confidence level is also included.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.519-522
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• 2003

'KRS 6330-3256라' standard regulates performance test of insulating transformer for protecting the electronic interlock linkage equipment which is being done by test procedures and methods according to the standard. The balance/unbalance test evaluating the performance of transformer are applied by impulse voltage($l2/200{\mu}s$) but affected by many other factors. Therefore, the review about these is necessary to have the reliability and reappearance of test results. In this paper, we have simulated about several phenomenon appearing in real balance/unbalance test and compared simulated results with real ones. With the basis of these results, the influence to test result of inner and outer factors are investigated and analyzed and established the plan boosting the reliability and reappearance of test results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.209-213
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• 2005

To enhance the reliability of distribution transformers in service and to reduce the cost of maintaining and replaceing these, the condition and life of those insulating system should be evaluated accurately and the time to replace should be determined economically. Since the transformer failures related to insulation failure indicates that the primary cause is normally mechanical failure of integrity due to loss of mechanical strength as a result of degradation, the tensile strength characteristics of paper during ageing under accelerated conditions in insulating oil and research trends for assessing the life of insulating paper were investigated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.2
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• pp.85-89
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• 2021

High reliability thin film transistors are important factors for next-generation displays. The reliability of transparent a-IGZO semiconductors is being actively studied for display applications. A plasma treatment can fill the oxygen vacancies in the channel layer and the channel layer/insulating layer interface so that the device can work stably under a bias voltage. This paper studies the effect of plasma treatment on the performance of a-IGZO TFT devices. The influence of different plasma gases on the electrical parameters of device and its working reliability are reviewed. The article mentions argon, fluorine, hydrogen and several ways of processing in the atmosphere. Among these methods, F (fluorine) plasma treatment can maximize equipment reliability. It is expected that the presented results will form a basis for further research to improve the reliability of a-IGZO TFT.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.253-272
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• 2015

Purpose: The purpose of this study is to enhance the reliability of quality inspection by standardize the fineness test method of the thermal insulator of military textiles Methods: We have measured the thermal insulator of military textiles by microscope with three different ways and the effectiveness of their difference were analyzed by one-way layout design. Results: We have suggest the standardized the fineness test method of the thermal insulator of military textiles through advanced research. As a result we have verified hollow ratio of heat insulating fiber affect fineness test methods. The fineness test method for the thermal insulator applied with different methods following hollow ratio. We have verified that when the hollow ratio over 90%, the fineness of the thermal insulator measured from fiber-length, if it has over 80%, the cross-section length of hollow and if it has less 80%, the cross-section area of hollow is applied, respectively. Conclusion: This study indicated that the test method of fineness shows high reliability. Heat insulating fibers which have high evenness shows narrow variations(5/% or less, only CV 25%) irrespectively under different testing equipment or institute. Based ons the results, we have suggest the standardization of test methods for fineness by microscope method and produced the registration of Group Standard in Korean Standards Association.

• Transactions on Electrical and Electronic Materials
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• v.6 no.6
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• pp.294-300
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• 2005

According to the trend for electric power equipment of high capacity and reduction of its size, the needs for the new high performance electric equipments become more and more important. On of the possible solution is high temperature superconducting (HTS) power application. Following the successful development of practical HTS wires, there have been renewed activities in developing superconducting power equipment. HTS equipments have to be operated in a coolant such as liquid nitrogen ($LN_2$) or cooled by conduction-cooling method such as using Gifford-McMahon (G-M) cryocooler to maintain the temperature below critical level. In this paper, the dielectric strength of some insulating materials, such as unfilled epoxy, filled epoxy, and polyimide in $LN_2$ was analyzed. Epoxy is a good insulating material but fragile at cryogenic temperature. The filled epoxy composite not only compensates for this fragile property but enhances its dielectric strength.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.452-454
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• 2003

$SF_6$ gas has been increasingly used as the insulating and arc-suppressing medium in switchgears which are used as the protection devices of power system. Nowadays, most of power companies adopted the $SF_6$ gas-type load break switch for increasing the reliability of distribution network by its superior durability against external environmental condition, in substitution for air-type and oil-type switches. But, it is important to establish the general estimation process for the testing and estimation for long-term reliability. Accordingly, this paper presents the reliability testing method for $SF_6$ gas load break switch which is based on the analysis of the failure mode and the statistics.

• Progress in Superconductivity and Cryogenics
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• v.13 no.3
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• pp.5-9
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• 2011

DC high-temperature superconducting(HTS) cable system has attracted a great deal of interest from the view point of low loss, dense structure and large capacity. A HTS cable system is made of cable and termination. The insulating materials and insulation technology must be solved for the long life, reliability and compact of cable system. In this paper, we will report on the dielectric breakdown characteristics of insulating materials for HTS cable and termination. The AC, DC and lightning impulse breakdown strength of laminated polypropylene paper(PPLP) and glass fiber reinforced plastic(GFRP) have been measured under nitrogen pressures in the range of 0.l-0.4MPa. PPLP and GFRP are found to have a significantly higher DC breakdown strength. Also, DC surface flashover voltage of negative polarity is slightly higher than that of positive polarity in GFRP.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.44-48
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• 1993

Recently, superconducting cable has attracted a great deal of interest from the viewpoint of energy saving, one of the most important and difficult problems to be solved to assure the high reliability, safety and economy of cable is breakdown is cryogenic temperature. In this paper, we will report on the characteristics and mechanisms of the breakdown and creeping discharge in cryogenic liquids, dual role of those as the cooling and insulating material, and composited system of cryogenic liquid - gas taking into consideration for application.

• Electrical & Electronic Materials
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• v.7 no.1
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• pp.15-24
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• 1994

For increasing the insulating proper-ties and the reliability of composite materials due to environmental aging, the electrical and mechanical characteristics of moisture absortion specimens and moisture desorption specimens were investigated. After moisture absorption wt% and moisture desorption wt% increased with time, a state of saturation arrived subsequent to a constant time. Moisture absorption constants with the layers of glass fiber showed 0.0117 in 1 layer, 0.0123 in 2 layers and 0.0152 in 3 layers. Electrical and mechanical characteristics dropped significantly with moisture absorbing in composite materials. Although moisture dried completly at 70.deg. C, it is impossible to obtain the electrical and mechanical characteristics before moisture absorption. Many defaults by moisture in composite materials exist at interface between epoxy matrix and filler.