• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1209-1210
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• 2008

According to previous report, aged sleeves for old transmission lines have variable defects such as biased installed case or corrosion of steel sleeve. Biased installed sleeve occupied 20 percent among the investigated aged sleeves. This defect must cause local heating of splice connector and limit power transmission capacity. It even inspire falling out of overhead conductor from sleeves. This paper studies thermal properties and tension for ACSR conductor in case of biased installed sleeve model. The detailed results were presented in the text.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1576-1586
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• 1996

The subject of this paper is the analysis of a Wire-TEM cell(W-TEM cell) which has an inner wire array rather than a metallic septum;its basic structure is similiar to a NBS TEM cell. To verify improved performances of this W-TEM cell as a standard EM field generator, well-known quasi-static approximations are employed and their resultant ingegral equations are numerically analyzed by moment method. Although the electric field strength of a W-TEM cell is 1.4 dB lower than tht of a NBS TEM cell, the uniformity of EM field patterns in a W-TEM cell is improved. It is also shown that the EM field distortions resulting from loading by the conditing objects under test(loading effects), are decreased considerably. This paper also deals with the investigations about relationship between the EM field distributions and the number of wire composing the inner conductor. Finally, the experimental analysis is performed on the practical model which is built on the basis of the design variables brought out by the theoretical andnumerical analysis.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.885-895
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• 1994

In this paper, we propose the one-Ampere conductor method which is able to calculate the flux distribution conceptually and easily, and the improved winding method which suppresses space harmonics of magnetormotive force and enhances the coefficient of utilization of primary iron core in tubular linear induction motor. We carry out no-load test to verify effectiveness of proposed method and analyze characteristics by finite element method. As a result, performances are improved and propriety of primary iron core is enhanced comparing with conventional model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.104-105
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• 2008

According to previous report, aged sleeves of old transmission line showed several defaulted installation patterns, which is biased or corrosive-fractured of steel sleeve installed cases. The latter case occupied almost 25 percent of investigated aged sleeves. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. This paper studies thermal properties and tension for ACSR conductor in case of fractured steel sleeve model. The detailed results were presented in the text.

• International Journal of Control, Automation, and Systems
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• v.5 no.3
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• pp.337-342
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• 2007

This paper proposes a helmet-type whole-head brain stimulator system considering a realistic head geometry. For more accurate design and computer simulations, a realistic volume conductor model was adopted and the current evoked on human cerebral cortex was analyzed using the boundary element method (BEM). To obtain a more focalized evoked current around the target points, various coil configurations were tested and an average targeting error of about 10 mm was obtained.

• Geomechanics and Engineering
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• v.25 no.4
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• pp.267-273
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• 2021

In this work, we compare the analytical solutions with the numerical solutions for photothermal interactions in semiconductor medium containing cylindrical cavity. This paper is devoted to a study of the photothermal interactions in semiconductor medium in the context of the coupled photo-thermal model. The basic equations are formulated in the domain of Laplace transform and the eigenvalue scheme are used to get the analytical solutions. The numerical solution is obtained by using the implicit finite difference method (IFDM). A comparison between the analytical solution and the numerical solutions are obtained. It is found that the implicit finite difference method (IFDM) is applicable, simple and efficient for such problems.

• Progress in Superconductivity and Cryogenics
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• v.9 no.4
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• pp.7-10
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• 2007

The transport current distribution across the tape width of a SmBCO coated conductor was investigated. The current distribution was estimated by applying an inversion process to the field distribution measured in the vicinity of the tape by using a scanning Hall probe method. The obtained result is well consistent with one predicted by the Bean model, however, at the edges the current are not constant and do not generally plateau, on the contrary.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1752-1758
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• 2015

This paper presents partial discharge localization in stator winding of generators using multi-conductor transmission line (MTL) and RLC ladder network models. The high-voltage (HV) winding of a 6kV/250kW generator has been modeled by MATLAB software. The simulation results of the MTL and the RLC ladder network models have been evaluated with the measurements results in the frequency domain by applying of the Pearson’s correlation coefficients. Two PD generated calibrator signals in kHz and MHz frequency range were injected into different points of generator winding and the signals simulated/measured at the both ends of the winding. For partial discharge localization in stator winding of generators is necessary to calculate the frequency spectrum of the PD current signals and then estimate the poles of the system from the calculated frequency spectrum. Finally, the location of PD can be estimated. This theory applied for the above generator and the simulation/measured results show the good correlation for PD Location for RLC ladder network and MTL models in the frequency range of kHz (10kHz<f<1MHz) and MHz (1MHz<f<5MHz) respectively.

• Progress in Superconductivity
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• v.8 no.2
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• pp.169-174
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• 2007

We measured the field profiles, H(x)'s of coated conductors by using scanning Hall probe method when various magnetic fields, $H{_\alpha}'s$ or currents, I's were applied. From the measured field profiles, we calculated the current profiles, J(x)'s by the inversion method. The calculated J(x)'s of coated conductors show some different properties from the standard critical state model. $J{_c}'s$ are inhomogeneous varying with the positions and are not constant when $H_{\alpha}$ or I changes. And when I decreases the features of current reversion are remarkably different from the model.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.1
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• pp.77-82
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• 2003

The ac loss is an important issue in the design of high-Tc superconducting power devices such as transformers and cables. In these devices many Bi-2223 tapes are closely stacked together and exposed to alternating magnetic fields that can have different orientations with respect to a tape. In such arrangement the magnetization loss is influenced by the screening current induced in adjacent tapes and thus different from that in a single tape. This stacking effect was experimentally investigated by measuring the magnetization loss in a stack, which consists of a number of tapes. First the magnetization loss in the single tape was measured in order to confirm the reliability of the loss data measured in the stack. The results for the single tape coincide well will the loss characteristics described in other previous works. For the stack In parallel and longitudinal magnetic fields the measured loss is Independent of both the number of tapes and stacking type. The longitudinal magnetization loss Is well explained rather by the slab model for decoupled filaments. For the tall stack in perpendicular field the measured loss at low fields is greatly decreased, compared to the loss of the single tape. However the loss at high fields is unaffected. These loss behaviors in the tall stack are well described by the slab model for full coupling.