• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1051-1053
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• 1999

In this work, thermal phenomena and temperature rise due to thermal source in electric switchboard were investigated using analytical measures. Electric switchboards are assemblies of panels on which are mounted switches, circuit breakers, high current busbars, meter, fuses and terminals essential to the operation of electric equipment. It is very difficult to predict the temperature rise in switchboard due to the existence of several heat sources. To overcome this situations, we focused on the eddy current distribution on the panel of switchboard caused by high current busbars as a fundamental basis. And thermal sources including busbar and switchgear have been considered. Furthermore, thermal transfer phenomena in switchboard was considered theoretically. Finally, three-dimensional thermal model for eddy current analysis has been adopted and FEM analysis was conducted. As a result, three-dimensional numerical analysis found to be applicable to the analysis of thermal phenomena in switchboard.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1113-1116
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• 2004

This paper presents the method for analyzing surface temperature of Electric incoming Apparatus. For the experiment, the surface temperature of electric power apparatus was measured and analyzed by using a infrared thermal imaging system. Surface Discharges(SD) have very complex characteristics of discharge patterns, therefore it requires the development of precise analysis methods. recently, studies on infrared thermal imaging system are carried out to analyze temperature distribution of power equipments through condition diagnosis and to diagnose the degradation of power equipments. The changes in suface temperature was measured by using the infrared thermal imaging system under hot line condition. The system was set up based on the diagnostic method of the electric incoming apparatus.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.145-150
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• 2015

This paper described the medium voltage high temperature superconducting cable thermal simulation and its application. New simulation method for HTS cable modeling using PSCAD/EMTDC is introduced in this paper. The developed simulation method consists of electrical model part and thermal model part. In electrical model part, power loss and thermal capacitance can be calculated in each layer, then the temperature of each layer can be calculated by power loss and thermal capacitance in thermal model part. This paper also analyzes the electrical and thermal characteristic in the case of normal operating condition and transient including single line to ground fault and line to line ground fault using new simulation method.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1503-1510
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• 2017

In this paper, a thermal analysis of a high speed induction motor with a PWM voltage source was performed by considering harmonic loss components. The electromagnetic analysis of the high speed induction motor was conducted using the time-varying finite element method, and its thermal characteristics were carried out using the lump-circuit method. Harmonic losses from tests in the high frequency region were divided into core loss and conductor loss components using various ratios, in order to determine the loss distributions for the thermal analysis. The results from both the calculations and experiment were validated using a high speed induction motor prototype operating at 20,000rpm.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.151-155
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• 2020

In this paper, a new experimental method to determine the thermal resistance of building wall was proposed by improving the heat flow method (HFM) based on the air-surface temperature ratio theory. This technique measures the thermal resistance of the wall excluding the inner and outer surface heat transfer resistance. Unlike conventional HFM, this value can be compared directly with the theoretical reference value. Its performance was verified using three mock-up structures with a theoretical thermal transmittance of 0.5, 3.3, and 0.18 W/㎡·K respectively. After measuring the variations in the temperature and heat transfer rate of the mock-ups for 383 hours, the thermal transmittances were determined to be 0.47, 3.10, and 0.18 W/㎡·K, which corresponded to errors of 5.2, 6.2 and 0.5%, respectively, compared to the theoretical values. It was concluded that this technique can directly compare the thermal resistance of the wall between the existent stage and initial stage after construction.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.113-119
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• 2015

The technical development of electric vehicles has been actively proceeding because of the reduction of oil resources and need for eco-friendly vehicle technology. In particular, an electronic control unit is an important element in the technology of electric vehicles due to the motor drive system. This paper concerns an experimental study on the thermal analysis of the steering control ECU structure for an electric vehicle. The ECU unit is designed for eight heat sinks for the thermal analysis of the ECU structure. The thermal analysis characteristics of the ECU structure are evaluated by the temperature distribution, heat flow, von Mises stress, total translation, and external surface temperature measurement of the ECU unit.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.214-220
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• 2011

This paper studies about the assessment of thermal performance between wet ondol system and electric ondol system. Electrical ondol systems shows faster warm-up time, higher floor surface temperature distribution and lower power consumption than wet ondol system. However, if we provide heat regularly wet ondol system which has more heat capacity shows greater thermal storage than electric ondol system. Therefore, we could conclude that wet ondol system which keeps temperature regularly by the thermal storage show better energy-efficiency in case of using the central heating and district heating system. However, Electrical ondol system shows better efficiency in case of using the space during short time or individual heating systems which needs to heat quickly. The Experiment says that electric ondol system has more benefits on timing to reach the set temperature and energy-efficiency than wet ondol system.

• Journal of Powder Materials
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• v.19 no.4
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• pp.285-290
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• 2012

The present study was focused on the analysis of the electric and thermal properties of spark plasma sintered $Bi_{0.5}Sb_{1.5}Te_3$ thermoelectric material. The crystal structure, microstructure, electric and thermal properties of the sintered body were evaluated by measuring XRD, SEM, electric resistivity, Hall effect and thermal conductivity. The $Bi_{0.5}Sb_{1.5}Te_3$ sintered body showed anisotropic crystal structure. The c-axis of the $Bi_{0.5}Sb_{1.5}Te_3$ crystal aligned in a parallel direction with applied pressure during spark plasma sintering. The degree of the crystal alignment increased with increasing sintering temperature and sintering time. The electric resistivity and thermal conductivity of the $Bi_{0.5}Sb_{1.5}Te_3$ sintered body showed anisotropic characteristics result from crystal alignment.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.893-898
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• 2014

Recently, the interior permanent synchronous motor (IPMSM) has been applied to an integrated starter and generator (ISG) for hybrid electric vehicles. In the design of such a motor, thermal analysis is necessary to maximize the power density because the loss is proportional to the power of a motor. Therefore, a cooling device as a heat sink is required internally. Generally, a cooling system designed with a water jacket structure is widely used for electric motors because it has advantages of simple structure and cooling effectiveness. An effective approach to analyze an electric machine with a water jacket is a thermal equivalent network. This network is composed of thermal resistance, a heat source, and thermal capacitance that consider the conduction, convection, and radiation. In particular, modeling of the cooling channel in a network is challenging owing to the flow of the coolant. In this paper, temperature prediction using a thermal equivalent network is performed in an ISG that has a water cooled system. Then, an experiment is conducted to verify the thermal equivalent network.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.1-4
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• 2005

A higher order zig-zag shell theory is developed to refine accurately predict deformation and stress of smart shell structures under the mechanical, thermal, and electric loading. The displacement fields through the thickness are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field. Smooth parabolic distribution through the thickness is assumed in the transverse deflection in order to consider transverse normal deformation. The mechanical, thermal, and electric loading is applied in the sinusoidal distribution function in the in-surface direction. Thermal and electric loading is given in the linear variation through the thickness. Especially, in electric loading case, voltage is only applied in piezo-layer. The layer-dependent degrees of freedom of displacement fields are expressed in terms of reference primary degrees of freedom by applying interface continuity conditions as well as bounding surface conditions of transverse shear stresses. In order to obtain accurate transverse shear and normal stresses, integration of equilibrium equation approach is used. The numerical examples of present theory demonstrate the accuracy and efficiency of the proposed theory. The present theory is suitable for the predictions of behaviors of thick smart composite shell under mechanical, thermal, and electric loadings combined.