• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.80-82
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• 2005

There is a method for stringing conductors which is connected to a wire over transmission towers by helicopter or human power and the wire and conductors are pulled by an engine puller. The length of one string section is usually 4-6 km and 2-4 conductors are strung at the same time with a single wire. A tensioner is used to maintain the sag and a running board is installed between the wire and conductors to prevent the rotation of conductors but the variance in topology, the line angle and unequal wiring tension between conductors causes conductor rotation damage or the conductor connection point to breakaway when the pulley is passed. This paper presents a method to prevent conductor rotation during stringing by inserting a pulley in the running board and equally maintaining conductor tension by sling wire after developing and testing.

• 대한전자공학회논문지TC
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• 제44권3호
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• pp.98-104
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• 2007

본 논문에서는 도체스트립을 이용하여 910 MHz와 2.45 GHz 대역에서 공진특성을 갖는 RFID 리더와 무선 LAN용 이중대역 개방루프안테나를 제안하였다 안테나의 입력임피던스는 안테나를 구성하는 도체스트립 선로의 길이와 폭을 변화시켜서 $50\Omega$을 갖는 급전선과 정합시켰다. 또한 안테나의 이득과 지향성은 도체스트립의 선로길이를 변화시키고 도체스트립에 teeth 모양의 홈을 만들어 향상시켰다. 제작된 안테나의 크기는 $75mm\times100mm$ 이고 반사손실과 이득특성은 910 MHz에서 -11.92 dB, 3.02 dBi 그리고 2.45 GHz에선 1.31 dB, 4.08 dBi를 갖는다.

• 한국인터넷방송통신학회논문지
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• 제13권4호
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• pp.201-208
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• 2013

본 논문은 한쪽 면이 열린 동축 공동 공진기의 경험적 설계 방법에 대한 연구이다. 공진기의 내부 도체 반경과 공진기의 내경 그리고 길이를 이용하여 설계한다. 그러나 기본 동축 선로 이론을 적용하면 내부 도체 반경과 공진기의 내경 값에 관계없이, 길이 변화에 의해서만 공진 주파수와 Q값의 특성이 달라지는 것을 알 수 있다. 따라서 내부 도체 반경과 공진기 내경 그리고 길이의 영향을 알아내고, 경험적 설계를 통해 이론값과 설계값의 오차를 줄여 최적화된 공진기 설계 방법을 제안한다. 모의실험 결과를 바탕으로 공진기의 내경은 14 mm, 내부 도체 반경은 각각 2 mm, 5 mm, 10 mm 그리고, 공진기의 길이는 8.5 mm로 제작하였다. 제작된 공진기의 공진 주파수는 6.1, 5.7, 6.5 GHz로 측정되었다. 모의실험과 제작된 공진기를 측정한 결과에 의하면, 공진기의 길이가 10 mm이하일 때는 기본 동축 전송 이론을 직접 적용하고, 10 mm이상 일 때는 계산된 공진 주파수에 0.5 GHz보정인자 값을 더함으로써 비교적 오차가 작은 한쪽 면이 열린 동축 공동 공진기를 설계 할 수 있음을 알 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.1-2
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• 2009

The high critical current ($I_c$, A) of SmBCO coated conductor in a magnetic field, the high production rate and the high material yield are promising for applications. The inhomogeneity of Ie at the long length coated conduct is very important problem for electric application. So we researched the reason of inhomogeneity of $I_c$ at long length tape prepared by batch type co-evaporation system called by EDDC. The long length SmBCO coated conductors were developed on $LaMnO_3/IBAD-MgO/Y_2O_3/Al_2O_3$/Hastelloy C276 template. The distribution of $I_c$ are from 0 to 397 A/cm at 77 K and self field. We have studied the microstructures of these films by using SEM, EDS and X-ray diffraction. The XRD and composition by EDS results of SmBCO film reveals subtle difference. But, the microscopic observation by SEM show the microcrack at the sample with low $I_c$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.290-291
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• 2008

Recently High Temperature Superconductor(HTS) Tape is limelight of the applied superconducting machines. Mainly used superconducting tape are BSCCO tape and YBCO coated tape. These superconducting tape are applied such as SMES, superconducting generator and MAGLEV. Actually superconductor tape's experimental gauge is short. For this reason, experiment was conducted. Firstly length of 50cm BSCCO, YBCO Coated conductor@Cu and YBCO coated conductor@sus are prepared. and flow the over-current. Secondly, BSCCO and Coated conductor connected with lenth of 25cm and flow the over-current. Coupled line of HTS tape was compared with single line of HTS tape and these overcurrent characteristics was investigated.

• 한국초전도ㆍ저온공학회논문지
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• 제12권2호
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• pp.9-12
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• 2010

A lamination system using reflow soldering was developed to enhance the mechanical properties of high temperature superconductor (HTS) tape. The laminated coated conductor tape was fabricated using the continuous lamination process. The mean, maximum, and minimum tensile loads in a T-peel test of the laminated coated conductor were 9.9 N, 12.5 N, and 7.6 N, respectively. The critical current ($I_c$) distributions of the non-laminated and laminated coated conductor were compared using anon-contact Hall probe method. The transport $I_c$ nearly matched the non-contact $I_c$; however, some degraded Ic regions were found on the length of 800 cm of laminated coated conductor. We confirmed that the cause of the partially degraded $I_c$ was due to an increase in line tension by (1) solidification induced by a change of composition that usually occurs in molten brass (Cu, Zn) in solder, or (2) non-homogeneity of the thickness of the coated conductor or metal tapes. We suggest that reflow soldering is a promising method for reinforced HTS tape if the controlling solder thickness and lamination guide are modified.

• 한국초전도ㆍ저온공학회논문지
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• 제15권2호
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• pp.24-28
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• 2013

In this study, the homogeneity of critical current, $I_c$, along the lengthwise direction in the coated conductor (CC) tape under uniaxial tension was investigated using a multiple voltage tap configuration. Initially, a gradual and homogeneous $I_c$ degradation occurred in all subsections of the tape up to a certain strain value. This was followed by an abrupt $I_c$ degradation in some subsections, which caused scattering in $I_c$ values along the length with increasing tension strain. The $I_c$ degradation behaviour was also explained through n-value as well as microstructure analyses. Subsections showed $I_c$ scattering corresponding to damaged areas of the CC tape revealed that transverse cracks were distributed throughout the gauge length. This homogeneous $I_c$ degradation behaviour under tension is similar with the case under torsion strain but different with the case under hard bending which were previously reported. This behaviour is also different with the case using Bi-2223 HTS tapes under tension strain.

• 한국초전도ㆍ저온공학회논문지
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• 제9권4호
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• pp.11-15
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• 2007

In practical applications of HTS tapes for electric devices such as coils and power cables, the jointing of HTS tapes is inevitable even though long length tapes have recently been achieved. The critical current, $I_c$, degradation behaviors with tensile and bending deformations were investigated in commercially available YBCO coated conductor tapes. When the V-I relationship was measured at the jointed section of the lap-jointed YBCO CC tapes, the resistance at the joint decreased with increasing joint length. The critical load for 95% $I_c$ retention were determined for the IBAD and RABiTS YBCO tapes and they were 175 and 355N, respectively. Fracture occurred at the unjointed part which represents strong copper lamination and solder jointing. The electro-mechanical properties of lap-jointed CC tapes depended on the properties of single tapes. The V-I behavior under bending strain was similar with the tensile case.

• 전자공학회논문지
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• 제50권3호
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• pp.230-236
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• 2013

본 논문은 대표적인 손실 매질인 대지에 위치한 도체의 입력임피던스를 MATLAB을 이용한 자체 프로그램을 활용하여 계산하고, 그 결과를 나타내었다. 도체의 입력임피던스는 안테나 이론의 전자계 모델에서 유도된 포클링턴방정식에 모멘트법이 적용되어 계산되었다. 결과의 정확도를 높이기 위해서 기저함수와 가중함수가 삼각함수인 켈러킨법을 적용하였다. 대지에 위치한 도체의 영상분은 수정된 영상법을 적용하여 고려하였다. 도체의 전류분포에 대한 자체 제작한 프로그램 결과와 NEC 프로그램의 결과를 비교하여 프로그램의 신뢰성을 확인하였다. 대지에 위치한 도체의 길이가 1 m, 2 m인 경우에 도전율에 따른 임피던스를 주파수에 따라 시뮬레이션 하였다. 실제 대지에 설치된 도체의 입력임피던스와 위상을 측정하고 동일한 조건에서의 시뮬레이션 결과와 비교하였다.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.334-337
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• 1999

High T$_c$ (${\sim}$21,500 A/cm$^2$, at 77K) of 100m length of BSCCO 2223 tapes have been achieved using optimized precursor powders with carefully controlling variables in heat treatment. Prototype 500A class multistrand conductor for HTS power cable was fabricated using these tapes. Also discussed are the transportation properties of prototype 500A class multistrand conductor.