• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.8
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• pp.334-340
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• 2006

Copper is widely used in electric wire, cable, conductor in electric devices. As the demand for electric power is increasing rapidly, electric power devices are getting amazingly bigger and complicated. The using of light-weight conductor can reduce the size and making cost of the electric devices. In high-frequency application, Electric current in a conductor tends to shift to the surface of the conductor, resulting in an uneven current distribution in the inner conductor. In the extreme case the current may essentially concentrate in the 'skin' of the inner conductor as a surface current. In high frequency application, therefore, inner area of copper conductor may replace with aluminum conductor, which reduces the weight of conductor. This paper describes the manufacture and evaluation of composite conductors made of copper and aluminum. The optimum extruding ratio was 16 at $300^{\circ}C$. The electrical resistance of manufactured composite bus bar was $57{\mu}{\Omega}$ at DC and $49.5{\mu}\{Omega}$ at 300Hz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.621-622
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• 2005

Copper is widely used in electric wire, cable, conductor in electric devices. As the demand for electric power is increasing rapidly, electric power devices are getting amazingly bigger and complicated. The using of light-weight conductor can reduce the size and making cost of the electric devices. In high-frequency application, Electric current the current in a conductor tends to shift to the surface of the conductor, resulting in an uneven current distribution in the inner conductor. In the extreme case the current may essentially concentrate in the "skin" of the inner conductor as a surface current. In high frequency application, therefore, inner area of copper conductor may replace with aluminum conductor, which reduces the weight of conductor. This paper describes the manufacture and evaluation of composite conductors made of copper and aluminum.

• Journal of electromagnetic engineering and science
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• v.4 no.1
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• pp.43-49
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• 2004

A low-frequency coaxial reflectometer(LCR) with a thin-wire inner conductor is designed and constructed to measure nondestructively the absorbing performance of electromagnetic absorbers in the frequency range of 10 MHz to 200 MHz. The LCR consists of a square coaxial transmission line and a network analyzer with a time-domain measurement capability. Inherent characteristics of a square coaxial line with a thin-wire inner conductor which deteriorate the impedance matching of the input port of the LCR are addressed. And the characteristics are improved by employing a multiwire inner conductor. Measured and calculated reflection losses of a flat ferrite tile absorber are presented.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1935-1937
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• 1996

This paper deals with ACSR(Aluminum Conductor Steel Reinforced) inner corrosion detection using a detector which automatically runs on an ACSR transmission line and inspects the inner corrosion of the conductor by utilization of the nondestructive eddy current test. And the relationship between the corrosion grades and the tensile strength can be estimated by means of this test. According to corrosion appearance and development of ACSR, the impedance change of the eddy current coils is theoretically verified. And then specifications And performances of the detector are described. Experimental procedures and desirable test results are reported. In conclusion, this detector can realize the nondestructive detecting of an ACSR inner corrosion. Upgrading the maintenance effciency and improving the reliability of transmission line would be expected by this nondestructive test method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.35-39
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• 2002

A defect detection test was performed for a conductor using a amorphous wire sensor head. A uniform magnetic field was applied in the space between the most inner conductors of a spiral-typed coil. The conductor with a defect was placed on the space between the most inner conductors of spiral-typed coil. The defect can be detected from the differences of induced voltage measured in the vicinity of gap of the conductor. The induced voltage difference of 2.5mV was measured in the gap vicinity of the 1mm thick conductor having 0.5mm gap in the frequency region of 100kHz~600kHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.201-208
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• 2013

This paper is a study of an empirical design of an open-ended coaxial cavity resonator. It can be done by using the radius of the inner conductor, the inner radius and the length of the resonator. However, the basic coaxial transmission -line theory can be seen that the characteristics of the resonant frequency and the Q value are varied by the change of length, regardless of the value of radius of the inner conductor and inner radius of the resonator. We find out the impact of radius of the inner conductor, inner radius of the resonator and the length of the resonator parameter and propose the optimized empirical resonator design method by reducing the error between the theoretical value and the design value. Based on the simulation, several resonators are fabricated by the size of 14 mm for the radius of inner conductor, 2 mm, 5 mm, 10 mm respectively for the inner radius of resonator, and 8.5 mm for the length of the resonator. The resonant frequencies of the produced resonators were measured at 6.1, 5.7, 6.5 GHz respectively. According to the result of simulation and measurement, we know that we can design the relatively exact open-ended coaxial cavity resonator by applying the basic coaxial transmission-line theory directly when the length of the resonator is less than 10 mm, and adding the correction factor of 0.5 GHz to the calculated resonant frequency in case of more than 10 mm of the length of the resonator.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1035-1038
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• 2007

We designed and manufactured a 1.8T high temperature superconducting(HTS) insert coil for a NMR magnet operated at 4.2 K. Suitable HTS superconductor and HTS coil were carefully designed and developed. We have selected multi-filamentary Bi2223 conductor fabricated by American Superconductor Corporation(AMSC). The selected conductor consists of Bi2223 filaments of 55, silver stabilizer and stainless steel reinforcement tapes. Therefore, it shows good hoop strength as well as compression tolerance. The conductor has a tape cross-section of 0.31mm x 4.8mm. the Bi2223 conductor shows large anisotropy of critical current. The critical current of conductor in magnetic field parallel to the flat surface are much higher than that in magnetic field perpendicular. The HTS coil has an inner diameter of 78 mm, an outer diameter of 127 mm and a coil length of 600 mm. In this paper, the detailed design, fabrication and test results on the HTS insert coil are presented.

• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.12-19
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• 1998

This paper deals with ACSR(Aluminum Conductor Steel Reinforced) inner corrosion detection using a detector which automatically runs on an ACSR distribution line and inspects the inner corrosion of the conductor by utilization of the nondestructive eddy current test. According to corrosion appearance and development of ACSR, the impedance change of the eddy current coils is theoretically verified. And then specifications and performances of the detector are described. Experimental procedures and desirable test results are reported. In conclusion, this detector can realize the nondestructive detecting of an ACSR inner corrosion. Upgrading the maintenance efficiency and improving the reliability of distribution line, whether is covered with insulating materials or not, would be expected by this nondestructive test method.method.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.269-271
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• 2003

A typical HTS power transmission cable has multi-layer conductor structure to increase the current capacity. The tapes of the innermost layer are wound on a round former, and adjacent tapes of another layer are separated by a thin insulating film. In steady state, the total current flows in the conductor layer, and consequently there is magnetic field between the inner and outer layer. This paper describes a magnetic field amplitude around the conductor layer and the HTS tape by a transport current. Also, this paper will help for future cable conductor prototypes.