• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2110-2113
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• 1999

This paper describes the initial characteristics of turbine generators at the Taean thermal power plant #4 and Wolsong nuclear power plant #2. The turbine generators had been in service for two years. The insulation diagnostic tests included measurements of insulation resistance, polarization index, ac current, dissipation factor($tan{\delta}$) and partial discharges (PD). The values of ac current and tan a were measured by Schering bridge. PD measurements were conducted using digital PD detector. The variation of $tan{\delta}$ and PD was confirmed in two generator stator insulations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.513-517
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• 1999

High voltage motor(rated 6.6kV and 448kw) has failed in the stator endwinding area during normal service. Experiments on microstructure property were conducted using the control and aged insulations, which were drawn out from stator windings of the high voltage motor. The analyses were characterized using stereozoom microscope(SM), scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy(EDS). SM result shows that large voids are present in the interface between turn insulation and groundwall insulation. SEM results indicated that the groundwall insulation is rarely thermal stress. EDS results showed that chemical elements in the high voltage motor stator insulations were Al, Si, O, K and Fe.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.184-192
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• 2012

For use as recyclable power cable insulations without dielectric oil, technology trends of IPP based thermoplastic polyolefin elastomer(TPO) nanocomposites were reviewed. In 2010 research results of IPP nanocomposite dielectrics for power capacitors showed promising high voltage properties except dielectric loss. Research of IPP based TPO nanocomposites for automotive exterior parts revealed considerable improvements of mechanical properties including impact strength, especially minimization of compatibilizer content, the origin of dielectric loss. A study on electrical properties of IPP based TPO nanocomposites containing a few weight percent of nanofillers for power cable insulations is suggested.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.1
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• pp.55-62
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• 2015

This study investigated the thermal insulation of an air-cell pack embedded jacket and down jackets to understand the potential of air-cell pack as a filler for winter outdoor wear. A thermal manikin measured the thermal insulation of the following jackets: HD (heavy down jacket, total weight (Tw) 750g, goose down weight (Dw) 350g), LD (light down jacket, Tw 560g, Dw 140g), AF (air-cell pack embedded jacket, Tw 490g, trunk goose down in LD was replaced to air cell), F (film jacket, Tw 469g, but removed the air in the air-cell pack from the AF), and Control (control jacket, Tw 438g, removed the air-cell pack film from the F). Thermal insulations of each experimental condition were measured in a static standing posture. Total thermal insulations (IT) were 1.29clo (HD), 1.23clo (LD), 1.16clo (AF), 1.20clo (F), and 1.08clo (Control). Body regional thermal insulation was higher in the chest and back than in the abdomen and hip in all conditions. The results suggest that an economical and versatile outdoor jacket with superior thermal insulation will be feasible if the air volume is properly controlled in air-cell pack embedded jackets in consideration of regional different distribution and used in combination with film and down.

• Transactions on Electrical and Electronic Materials
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• v.17 no.5
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• pp.239-251
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• 2016

The potential of nanocomposites have been drawing the intention of the researchers from energy storage to electrical insulation applications. Nanocomposites are known to improve dielectric properties, such as the increase in dielectric breakdown strength, suppressing the partial discharge (PD) as well as space charge, and prolonging the treeing, etc. In this review, different theories have been established to explain the reactions at the interaction zone of polymer matrix and nanofiller; the characterization methods of nanocomposites are also presented. Furthermore, the remarkable findings in the fields of epoxy, cross-linked polyethylene (XLPE), polypropylene and polyvinyl chloride (PVC) nanocomposites are reviewed. In this study, it was observed that there is lack of comparison between results of lab scale specimens and actual field aged cables. Also, non-standardization of the preparation methods and processing parameters lead to changes in the polymer structure and its surface degradation. However, on the positive side, recent attempt of 250 kV XLPE nanocomposite HVDC cables in service may deliver a promising performance in the coming years. Moreover, materials such as self-healing polymer nanocomposites may emerge as substitutes to traditional insulations.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.221-231
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• 2005

In this study, occupational exposures to man-made mineral fibers (MMMFs) including glass wool, rock wool, and continuous glass filament fibers were determined and evaluated on the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV). A total of 171 personal samples collected from 4 glass wool fiber, 2 rock wool fibers, 4 continuous filament glass fiber products manufacturing and a glass fiber and rock wool insulations using industries, and determined respirable fibers concentrations using the National Institute for Occupational Safety and Health (NIOSH) Method 7400, "B counting rule. The fiber concentrations of samples from workers installing thermal insulations in a MMMF using industry showed the highest value: geometric mean (GM) = 0.73 f/cc and maximum = 2.9 f/cc, 70% of them were above the TLV, 1 f/cc. Workers' exposure level (GM= 0.032 f/cc) in the rock wool manufacturing industries was significantly higher than those of glass wool (GM=0.012 f/cc) and continuous filament glass fibers (GM=0.010 f/cc) manufacturing industries (p<0.01). No samples were more than the TLV in the MMMF manufacturing industries. There was a significant difference among companies in airborne fiber levels.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.115-120
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• 2003

Several methodologies were devised to reasonably predict the temperature boundary conditions of inner face of the concrete outer tank so as to set up heat transfer analysis model of the full containment above-ground LNG storage tank. In this model, outer tank is solely taken into account and the beneficial effect of suspended deck and insulation layers on the temperature distribution of outer tank is separately formulated according to the proposed procedures. More effective design of the insulations can be achieved when the proposed simple schemes are used in the preliminary stage.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.4
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• pp.68-78
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• 1992

Vibration and vibro-acoustic characteristics of body panels enclosing the vehicle interior cabin are tested and analyzed for effective application of sound proofing materials. A set of deadener and insulation packages are proposed based on the experimentally evaluated and categorized contributions of noise radiating panels. The suggested packages are applied to a prototype vehicle, and a refined acoustic quality is achieved. A systematic experimental procedure proposed in this study can be a good tool in tuning the acoustic quality of prototype vehicles within a limited development period.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.11
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• pp.918-927
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• 2003

This study is to analyze thermal characteristics of the basement structures with a non-thermal insulation and various thermal insulations. From the results through the field experiments and computer simulations, the thermal bridges and heat loss is found in non-insulation structure of the basement under the definite depth of ground level. Therefore, the thermal insulation structure should be installed for preventing the heat loss in the basement.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.5 s.51
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• pp.49-61
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• 2006

The floor impact sound insulations are installed frequently for reducing the floor impact sound into the floor slab of the residential buildings in recent years. Therefore the analytical FE model considering the insulation is needed for the sound and vibration analysis of the floor and it is necessary to use a refined finite element model fer considering the large number of modes involved dynamic responses. So it is very difficult to use FE model because of the tiresome task for constructing the FE model, taking a lot of times for analysis and the impossibility of using the proportional damping. The efficient analysis and modeling method are proposed to the dynamic analysis for the floor with damping layer in this study. The floor slabs and finished layers are modeled individually and the spring elements that mean damping layers used to connect two parts. The dynamic analysis by the $Newmark-{\beta}$ method is performed to solve the non-proportional damping problem due to the damping coefficient of insulations.