• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.4
• /
• pp.464-470
• /
• 2018

A development of one-dimensional thermal analysis tool is performed to estimate the thickness of cork insulation for flight vehicle. In the calculation of cork temperature, the cork density model, heat of ablation and pyrolysis gas enthalpy model were applied. The calculation for the two-layer model of cork and metal was performed by the tool and compared with the experimental data. The results for the two aerodynamic heating conditions were 17 % and -12 % different from the experimental data, respectively. The effect of mechanical ablation not included in the calculation can be expected as the cause of the difference. The temperature-density curve of cork which adjusted by experimental data was also presented.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.730-735
• /
• 2009

The purpose of this study is to consider improvement performance to prevent condensation and draw the optimum insulation design method for building using simulation tool. In this study, the three corners, weak part in condensation, were conducted by three-dimensional steady state simulation. From the results, it is required to strengthen insulation design, and it is founded that existing insulation system typically applied to most Korean apartment buildings has serious insulation defect that insulation is disconnected by structural components at the joints of wall-slab and wall-wall in envelope. So, it is considerate to need a concrete technology improvement.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1575-1577
• /
• 1999

XLPE is widely used as a main insulation in EHV power cables, deeply connected with thermal stress. In this study, the thermal history of XLPE insulation was examined using DSC(Differential Scanning Calorimetry). The principle is on the basis of the phenomenon that crystal in polyethylene is rearranged as it is annealed near/below the melting temperature. From the result, it was possible to define accurate temperature which was really applied on the XLPE insulation and this method was assured as a useful tool in characterization of thermal history in XLPE cable insulation.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.45 no.2
• /
• pp.294-300
• /
• 1996

In hydro-generator, a groundwall insulation of stator windings gradually deteriorates due to mechanical, thermal, electrical and environmental stresses. These stresses combine to result in loose windings, delamination of the stator insulation and/or electrical tracking of the endwinding, all of which can lead to stator insulation failures. Conventionally, off-line tests such as partial discharge measurement, DC/AC current and .DELTA.tan.delta. tests has been used for estimation of winding condition. However, off-line test requires large power supply and generator outage. In addition, major cause of insulation problems such as loose wedges and slot dischages may not be found with off-line diagnoses. This paper introduces the on-line partial discharge measurement techniques using frequency spectrum analyzer(FSA) for the generator stator windings. The experimental results from the UIAM #1 hydro-generator confirms a optimistic application of on-line generator diagnosis method as a reliable tool for evaluation of winding condition.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.6
• /
• pp.404-412
• /
• 2010

The purpose of this study is to accomplished an in-site evaluation method for existing building insulation status using Infra-red camera and to consider improvement performance to prevent condensation and draw the optimum insulation design method for building using simulation tool. The research contents of this study are to evaluate validity and suitability of building insulation defect survey using Infra-red camera for apartment housing with temperature and heat flow pattern analyze method. Based on this research, the three corners, weak part in condensation, were selected in apartment building and conducted simulation by three-dimensional steady state. From the results, it is required to strengthen insulation design, and it is founded that existing insulation system typically applied to most Korean apartment housings have serious insulation defect that insulation is disconnected by structural components at the joints of wall-slab and wall-wall in envelope. Thus, it is considerate to need a concrete technology improvement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.174-177
• /
• 2003

Comparisons of measuring apparatus for sound insulation are made between a reverberation chamber and a simplified test apparatus(APAMAT II) that is used to measure sound insulation performance of inner panels for automobiles. Also, theoretical prediction by using sandwich model are made in order to compare it with experiments and to consequently provide a design tool. Comparative results show that steel ball excitation in APAMAT II has a serious problem with sound insulation performance at the low frequency region, while speaker excitation gives a good agreements with theoretical prediction.

• Transactions on Electrical and Electronic Materials
• /
• v.7 no.5
• /
• pp.230-234
• /
• 2006

One of the methods currently being investigated as a possible non-intrusive diagnostic tool for condition monitoring of power transformer and cable is the recovery voltage measurement, which will be improving the ability to detect the content of water concentration and the ageing process in the insulation system and may thus be an indicator of insulation quality and its ageing status. The polarization phenomenon was studied using RVM with oil-paper samples. In order to interpret its mechanism, the Extended Debye model was introduced. With different circuit parameters, various simulation results were gotten. Furthermore, with the test samples of different ageing condition, measurements are accomplished in the lab. On the basis of this experiment as well as theoretical analysis, correlations between polarizations and ageing were analyzed.

• Progress in Superconductivity and Cryogenics
• /
• v.13 no.1
• /
• pp.46-50
• /
• 2011

The electrical insulation design of high voltage superconducting fault current limiters (SFCLs) should be confirmed to be applied for the stabilization of the power grid. This paper describes numerical analysis and AC dielectric experiments for developing high voltage SFCLs. The electric field distributions between applied high voltage part and ground were calculated by finite element method (FEM) simulation tool and AC criterion of liquid nitrogen at 200 kPa was calculated from correlation between the field utilization factor and FEM simulation results. This paper deals with ceonceptual insulation design of a 154 kV class single-phase no-inductively wound solenoid type SFCL which was focused on gap distance between the cryostat and superconducting coils. Furthermore, the shield ring effect was confirmed to reduce maximum electric field at applied high voltage part.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.65-69
• /
• 2007

Recently, the method of the apartment building design is changing from wall type to moment structure. Because of this reason, dry wall systems are used plentifully. This study examines the sound insulation performance of the light weight concrete panel using bottom ash. There is the difference of airborne sound isolation between laboratory and field test. For the purpose of searching deviation, we use the prediction tool(Insul 6.0). First, we calculated the prediction data and measured the sound isolation in the wall at the lab. Then, we measured it in the field and compared them. At the base of these datum, we measured the difference.

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