• Journal of Energy Engineering
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• v.29 no.1
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• pp.25-33
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• 2020

Recently, as the mandatory policy of zero energy building is promoted, policies / systems for transition to Zero Energy School are being promoted, but there is no method to systematically analyze and verify the results of energy saving activities for school buildings. For the study of energy performance verification methodology, the current status of related standards was referred to, and the case study of other methodologies was conducted to examine the tools that can analyze the performance in the field. In addition, this study analyzed the current status and characteristics of energy management through domestic school visits. In this paper, we presented various energy saving projects such as air conditioning and heating facilities, lighting, insulation, change operation behavior, and improve operation methods in new and existing school buildings, and M & V methods for verifying energy savings before and after implementation of energy conservation projects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.232-235
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• 2002

Recently developed liquid silicone rubber (LSR) can be cured by platinum catalyzed additional hydrosilylation mechanism and has the advantage of no byproduct compared to traditional millable peroxide curing silicone rubber. We investigated the characteristics of dielectric breakdown of silicone rubber and adhesion properties between semi-conductive LSR and insulating LSR for high voltage application of pre-molded joint (PMJ). In order to understand the dielectric breakdown characteristics, we used the sheet samples and the paired type rogowski insert electrode system. The breakdown strength and adhesion strength of LSR (E-3) were superior to those of several silicone rubbers. Adhesion strength could be improved by curing at high temperature without post-curing process or enhanced by post-curing process. When LSR (E-3) was cured at $(150^{\circ}C{\times}10min$ semi-conductive )${\times}$ ($175^{\circ}C{\times}10min$ insulation), it showed the high breakdown strength with low standard deviation, and good adhesion strength. In this results, we could apply this process to the fabrication of PMJ without post-curing.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.28-33
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• 2015

The needle electrode is inserted into the cross-linked polyethylene(XLPE) which is the ultra high voltage cable for electric power. By changing the tilt of the needle electrode, we investigated how the void and the thickness of the insulating layer influence the partial discharge(PD) characteristics and the insulating breakdown. In order to investigate the PD characteristics, The XLPE cable was used to the specimens and the tungsten electrode was used with the needle electrode. And the inner semi-conductive layer material of XLPE cable was used with the negative electrode by bonding with the use of conduction tape. The size of the specimens was manufactured to be $16{\times}40{\times}30[mm^3]$. We confirmed the effect on changing the PD characteristics according to the changing voltage and the tilt of the electrode after applying the voltage on the electrode from 1[kV] to 40[kV] at room temperature. In the PD characteristics, it was confirmed that the PD current of air void specimens with tilt was unstable more than that of no void specimens with tilt. It was also confirmed that the breakdown voltage was decreased because the effect of air void is more active than the change of the needle electrode tilt in the specimen with air void inside the insulation.

• Journal of the Korea Concrete Institute
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• v.22 no.2
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• pp.229-235
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• 2010

In this study, fire resistance performance of high strength concrete specimen with fireproof gypsum board was investigated for possible use in upgrading fire-resistant performance of the existing building and repair of fire damaged structures. Fire test of eight identical high strength concrete columns were carried out for 180 minutes in accordance with ISO-834. The temperature distributions in longitudinal reinforcement and concrete temperature at various depths were recorded. The fireproof performance of gypsum board and explosive spalling of concrete were observed. The specimens with 15 mm thick twoply fireproof gypsum board spalled after gypsum board crumbled regardless of fastening methods. However, when the thickness of fireproof gypsum board was more than 30 mm, it was possible to prevent the explosive spalling and control the rebar temperature. Although the effect of cover thickness could not be compared because the explosive spalling occurred, there seemed to be no difference in insulation efficiency.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.669-672
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• 2008

To analyze possibility for high performance concrete that massively displaces blast furnace slag, this study analyzed the characteristics of concrete by blast furnace slag displacement rate changes, and the results are summarized as follows. Firstly, as for fresh concrete characteristics, flow tended to increase and air amount decreased with increase in blast furnace slag displacement rate, and settling time was shown delayed. As for hardened concrete characteristics, in conditions where blast furnace slag displacement rate increased up to 50%, the compressive strength decreased below OPC at early age, however at age 28 days, its level was no less than that of OPC, and as for temperature rise by simple insulation, it decreased as displacement rate increased at early stage of hydration, but in the latter stage, hydration progress slowed down and hydration heat increased.

• Journal of the Korea Institute of Building Construction
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• v.20 no.1
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• pp.53-60
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• 2020

This paper aims to examine the insulation performance of insulated gang form by changing the energy (power) consumption and concrete calorific value to assist in concrete protection in cold weather. According to the test results, the general gang form will generate three times the energy (power) consumption for 12 hours after the concrete is poured. In contrast, insulated gang foam consumed no energy (power) for 21 hours after pouring. The final power consumption was 3.7 times higher than that of the general gang form, confirming the improved performance of insulated gang form with regard to energy (power) consumption. The calorific value examination shows that the calorific value changes significantly according to the change of outside temperature after concrete placement in the case of the general gang form. However, in the case of the insulated gang form, only a slight heat loss occurred in the part of the frame, and it showed a constant heating pattern from the concrete casting to the demolding of the mold.

• Journal of Fashion Business
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• v.11 no.3
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• pp.15-34
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• 2007

This study was designed to collect a precise information concerning to the preference and evaluations after usage of pregnant Korean woman for the maternity wear bysurvey and wear tests. Through the survey, 212 respondents were asked to answer what type of maternity wear they prefer and what requirements for maternity wear design are important. According to the results of survey, the mostly preferred maternity wear items were pants and one-piece dress. Korean customers for maternity wear usually pay more for the one-piece dress than other items and they also usually put on medium price pants and low-price blouse. Concerning to the purchase criteria, it may be said that design and movability, fit factors are the buying decision criteria of great weight for Korean pregnant women. Special function most desired was thermal insulation, followed by buffer action, electromagnetic shield and quickly water-absorbent and dry property. Preferred maternity wear design details were flat collar, slightly fitted waist and empire style, gather skirt, rubber band waist. Wear test was performed for two kinds of blouse (BL) and one-piece dress (OP), and threekinds of pants (PT), which have different design details respectively. According to the wear test for ready-to-wear maternity garments, the garment which considers well the characteristics of Korean pregnant women body shape earned much higher score no matter of brands or prices. Generally, high-priced national brands received an excellent evaluation in design aspect, but not satisfied with comfort to move.

• Journal of the Korean Society of Safety
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• v.26 no.4
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• pp.41-46
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• 2011

The purpose of this paper is to analyze the causes of accidents related to the 3 phase 170 kV gas insulated switchgear of a power system collected from accident sites to secure data for the prevention of similar accidents and provide important points of view regarding diagnosis for the prevention of accidents involving gas insulated switchgears. The analysis results of the causes of accidents involving gas insulated switchgears showed deformation of the manipulation lever installed at the S-phase, disconnection of the insulation rod connection, melting of the upper conductor, a damaged tulip, damage to the lower spacer and the spacer at the breaker, etc. It is believed from this result that the potential for accidents has expanded due to accumulated energy as a result of repeated deterioration. The carbonization depth of a GIS was formed near the screw (T2, T3) used to secure the lower pole of the S-phase tulip. It is not known what has caused the screws to be extruded and melted. However, it is thought that an unbalanced electromagnetic force, micro-discharge, surface discharge, etc., have occurred at that point. In addition, even though 16 years have passed since its installation, there was no installation defect, act of arson, accidental fire, etc. General periodical inspection and diagnosis failed to find the factors causing the accidents. As a system contained in a closed metal container, it has a high risk factor. Therefore, it is necessary to design, install and operate a GIS in accordance with the standard operational procedure (SOP). In addition, it is necessary to apply conversion technology for periodical SF6 gas analysis and precision safety diagnosis. It is expected that tracking and managing these changes in characteristics by recording the results on the history card will provide a significant accident prevention effect.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.98-103
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• 2015

Power plant is that very high reliability when industrial and economic impact on the overall electric power system is required, it is essential to improve the reliability, especially the fault prediction diagnosis. Since an accident caused by the partial discharge in the power plant is above state has a faster response characteristic than the other indications in the case of any, the partial discharge generated in the power plant immediately detect the deterioration of insulation due to the accident of the power plant and the non-drawn It should prevent or reduce. Partial Discharge Measuring Systems for UHV SF6 Gas Insulated Switchgear and power transformer on site installed has some probability of abnormal recognition in case of non-flexible deal with on site noise. Many methode to eliminate these kinds of noises, UHF Detection System is chosen as purchase description in Korea, but this system having a bandwidth between 500MHz 1.5GHz wide band. Initial install periods(about 20 years ago), this band had no strong signal source, but in these days this wide band have strong signals, such as LTE. So, module described in this paper is designed as simultaneously use with wide and narrow band for solve this noise problem, and introduce this system.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1234-1236
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• 2005

High temperature superconducting(HTS) windings for an HTS transformer which have been developed have two kinds of type, one is the layer type and the other is disk type. The disk type windings have advantages over the layer type ones for a power transformer such as good insulation and limit of voltage stress. But this kind of HTS winding generates excessive AC losses caused by strong magnetic field component perpendicular to the surface of the HTS wire. Nevertheless, the layer type windings have adopted for an HTS power transformer so far because of the small AC losses of the HTS windings. We propose a new winding method for a high voltage HTS transformer which has advantages of both type of HTS windings, and we call it continuous disk type HTS winding. This new type of HTS winding consists of pile of lots of HTS disk windings which have no resistive joint between them. A prototype of an HTS winding was fabricated by the new winding method we proposed and characteristic test was carried out. The test result shows that the new type HTS windings can be applied to HTS power transformers, especially to the high voltage ones.