• 전기학회논문지
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• 제57권10호
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• pp.1713-1719
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• 2008

A high temperature superconducting power cable (HTS power cable) was applied large current capacity by no resistance in normal state. Fault state was risen out of over-current but, it was limited to resistance. This study was modeling equivalence, and unbalanced state analyzed operating characteristic of HTS power cable. The equivalence model was composed superconductor, shield, and former part. This model simulation was appeared conductor and shield current in normal state, but unbalanced state was appeared former current as rise current by resistance. So it need to sufficiently influenced the quench characteristic when the former design.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2007년도 춘계학술대회
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• pp.244-249
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• 2007

In this paper, in order to get the characteristics of the lithium secondary cell, such as cycle life, charge and discharge characteristic, temperature characteristic, self-discharge characteristic and the capacity recovery rate etc, we build a mathematical model of battery. In this one-dimensional model, Seven governing equations are made to solve seven variables $c,\;c_s,\;{\Phi}_1,\;{\Phi}_2,\;i_2,\;j\;and\;T$. The mathematical model parameters used in this model have been adjusted according to the experimental data measured in our lab. The connecting research of this study is to get an accurate estimate of the capacity of battery through comparison of results from simulation and fuzzy logic system. So the result data from this study is reorganized to fit the fuzzy logic algorithm.

• 한국초전도ㆍ저온공학회논문지
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• 제5권2호
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• pp.36-40
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• 2003

Inductive superconducting fault current limiter(SFCL) with DC reator rated on 6.6k $V_{rms}$/200 $A_{rms}$ has been developed in Yonsei University. The development of the DC reactor is the key technology in this type SFCL. This paper deals with the fabrication and characteristic test of the DC reactor. For the development of this magnet, the winding machine for high-Tc superconducting solenoid was manufactured. Using this machine, a large-scale HTS solenoid using Bi-2223 tape was fabricated successfully. This coil has 5 layers which are connected in series each other. The inductance of the DC reactor coil is 84mB. The cooling system was the sub-cooled nitrogen whose temperature is about 65K. The characteristic test of the coil was performed. The full quench current of this coil is about 490A.90A.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.607-610
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• 2003

The characteristic prediction and analysis of 3-dimensional (3-D) solenoid-type embedded inductors is investigated. The four different structures of 3-D inductor are fabricated by using low-temperature cofired ceramic (LTCC) process. The circuit model parameters of the each building block are optimized and extracted using the partial element equivalent circuit method and HSPICE circuit simulator. Based on the model parameters, predictive modeling is applied for the structures composed of the combination of the modeled building blocks. And the characteristics of test structures, such as self-resonant frequency, inductance and Q-factor, are analyzed. This approach can provide the characteristic conception of 3-D solenoid embedded inductors for structural variations.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.100-105
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• 2003

With the recent development of machining technology, high speed machining process is widely used for-the mold and difficult-to -cut-materials machining since it allows achieving high productivity and surface quality. However, during the high speed machining process, high cutting speed and feed rate can cause abrupt tool life decrease due to rapid rising of the cutting tool temperature. Such situation may cause increase of machining cost. Thus, in this study, developed optimization algorithm is applied to determine optimal machining variables for multiple high speed machining. The R-T characteristic curve for machining economics problems with a linear-lorarithmic tool life model is determined by applying sensitivity analysis. finally, a series of high speed machining experiments are performed to determine the desired optimal machining variables, and the results are analyzed.

• 한국전기전자재료학회논문지
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• 제22권3호
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• pp.210-217
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• 2009

Insulated methods of compact bus duct has been applied a way of coating Epoxy powder. The problem which is caused by degradation during operation is very important in severe environment. Therefore, this study compared and verified many kind of properties ; electrical breakdown by thermal and water aging, v-t characteristic, arc discharge, mechanical properties, bending test and cross cut. Sample D was stable before the $T_g$ to be about $7{\sim}10 %$ decrease in the breakdown test according to temperature change. In case of V-t and arc discharge, it had been kept up suitable characteristic. Also, in case of electrical and mechanical characteristic, both sample D and A have excellent capacity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1446-1448
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• 2002

The short-time permissible temperature of an overhead distribution line conductor is determined by the softening characteristics of ACSR-OC, ACSR AW/OC 160, typical conductors employed in the overhead distribution line. Transient heat transfer equation and Newton's cooling law were applied to analyze the heating and cooling effects of the insulating conductors, respectively, and the error of co-relation was calibrated after simulating the softening test to assess the short-time characteristic of the insulating conductor. In order to verify the softening characteristic, the conductors were tested with heat cycle. The test was totally carried out 200 cycles, and 1 cycle was to heat and cool at 1.1 times permissible current of the conductor, 1.15 times for 120 minutes, respectively. After heating, the tensile strength and surface of the conductor were observed. In case of ACSR-OC, as the result of 100 hour heating test, the tensile strength of the insulator was 0.8 times the initial value. This is equivalent to the value of the conductors which are used for 10 years at sites.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.11-15
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• 2002

This paper presents the thermal characteristic analysis of a high-speed HMC with spindle speed of 50,000rpm. The spindle is supported by two radial and axial magnetic bearings. and the built-in motor is located between the axial and rear radial magnetic bearings. The X-axis and Y-axis feeding systems are composed of linear motor and linear motion guides, and the Z-axis feeding system is composed of servo-motor, ballscrew and linear motion guide. The thermal analysis model of high-speed HMC is constructed by the finite element method, and the thermal characteristics in the design stage are estimated based on the temperature distribution and thermal deformation under the conditions related to the heat generation of built-in motor, magnetic bearings, linear motors, servo-motor, ballscrew, and so on.

• 한국초전도ㆍ저온공학회논문지
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• 제4권2호
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• pp.47-51
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• 2002

In this paper, flux distribution and operating current is calculated according to the field coil change in HTS(High Temperature Superconducting) motor. In order to calculate magnetic field characteristic of the field coil. it is computed by changing the outer radius and the inner width of field coil Bio-Savart equation is used as the analysis method for the characteristic analysis of magnet. 2D and 3D FEA(Finite Element Analysis) is used for the magnetic field distribution in HTS motor The operating current is calculated by $B{\bot}$ linked With the field coil and $I_c-B curve of superconductor.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.49-50
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• 2019

In the case of High-rise buildings, it has a problem by stack effect that rise of vertical height. Especially in case of fire, it need to the consideration of stack effect that it has bigger than general. Therefore in this study, we used to the Contamw and FDS simulation for analysis of stack effect and pressure distribution characteristic in fire. As a result the Contamw simulation shows the pressure distribution by stack effect in general high-rise buildings. However, in case of fire, the height of the neutral plane is lowered and stack effect is larger. Therefore, it is necessary to multiply analyze the temperature distribution and the stack effect in fire.