• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1731-1733
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• 1997

The first 150lkV underground transmission line of Korea was installed between Danginri and Yongsan substation in 1974. Since then, the underground transmission lines of about 720 circuit-km had been installed up to 1995. As the national economy has been enlarged and the population of city has been rapidly increased, the demand of an electric power has been very increased. Therefore the first 345kV long-length transmission line of Korea was installed between Mikyum and Sungdong substation on Jan., 1997. This paper describes the design of the 345kV oil-filled cable and its accessories, the design of the system, the methods of installation, field tests, and the future trends of the underground transmission line in Korea.

• Fashion & Textile Research Journal
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• v.20 no.1
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• pp.101-107
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• 2018

The purpose of this study is to develop the electroconductive textiles based on polyurethane(PU) nanoweb and to explore that it is applicable to smart clothing. The electroconductive textiles developed by coating 2.0 wt% aqueous dispersed non-oxidized graphene paste on the surface of PU nanoweb. The fabricated electroconductive nanoweb was applied as a transmission line to connect the LED lamp, and the brightness of the LED lamp was measured to confirm its performance. The nanoweb transmission line was fixed by two methods(seam sealing tape, embroidering) to connect the LED lamp and AA batteries. The results as follows, the brightness of the LED lamp fixed with seam sealing tape was about 82 lux, and which fixed with embroidering was about 57 lux. It represents that the nanoweb transmission line which fixed with the seam sealing tape has better electrical signal transmitting because the lux value higher than the one fixed by embroidering. In order to compare the performance of the nanoweb transmission line and the metal wire, we connected the LED lamp with copper wire. The brightness of copper wire connected LED lamp was about 193 lux. Although the electrical signal strength of the nanoweb transmission line was weaker than the copper wire, it was reachable to operate LED lamp. The results of this study will provide a basic data to develop the textile based electronic devices, and conducting wire for smart clothing.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.510-510
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• 2012

반도체, 디스플레이, 태양광 등의 공정에서 사용되는 웨이퍼의 크기가 증가하고, 생산률이 플라즈마의 밀도에 비례한다는 연구 결과가 발표되면서 대면적 고밀도 플라즈마 소스 개발에 대한 연구가 활발히 진행되고 있다. 특히, ECR, ICP, Helicon plasma 등 고밀도 플라즈마 소스에 대한 관심이 높아지고 있다. 이에 따라, 여러 개의 ICP를 결합한 multiple ICP를 이용해 대면적 고밀도 플라즈마 소스 개발을 진행했다. Multiple ICP의 경우 각 ICP 소스에 같은 power (current)를 공급해야만 균일한 플라즈마 방전이 발생되어 균일도를 확보 할 수 있다. Current controller 같은 추가적인 장비를 설치하지 않고, power를 분배하는 transmission line을 coaxial 형태로 설계하고 같은 길이로 병렬 연결함으로써 각각의 ICP소스에서 균일한 플라즈마를 방전시킬 수 있었다. Power generator에서 보는 각 ICP의 total impedance는 각 ICP 소스의 impedance와 coaxial 형태의 transmission line의 characteristic impedance, frequency, 길이의 함수로 구할 수 있고, 이 total impedance가 일정하기 때문에 current가 균등하게 분배되어 각 ICP소스에 균등한 power 분배가 가능한 것이다. 실질적으로 ICP 소스의 impedance는 플라즈마 방전 유무에 따라 변화하기 때문에 일정하게 유지하는 것은 어렵다. Transmission line의 characteristic을 사용함으로써 ICP의 impedance의 변화에 상관없이 Total impedance를 일정하게 유지시킴으로써 균등한 power 분배가 가능하다는 것을 연구했다. Frequency는 13,56MHz, characteristic impedance를 $50{\Omega}$ (coaxial cable)으로 고정하고, ICP 소스의 플라즈마 방전 유무/antenna turn/소스 위치에 따른 total impedance를 transmission line의 길이에 따라 측정하고, 이를 이론값, 그래프와 비교하였다. 특정 length에서 플라즈마 방전 유무(ICP의 impedance 변화)와 상관없이 비교적 일정한 total impedance를 유지하는 것을 확인 했다. 이것은 특정 길이를 갖는 coaxial형태의 transmission line를 연결하면, total impedance는 플라즈마 방전 유무로 발생하는 ICP의 impedance 변화와 상관없이 일정하게 유지되어 각 ICP소스에 균등한 파워 분배가 가능하다는 것을 보여준 결과이다. 이것을 토대로 frequency에 따라(또는 characteristic impedance에 따라) 균등한 파워 분배가 가능한 coaxial 형태 transmission line의 특정 길이를 구할 수 있고, 대면적 소스에서 균등한 파워 분배를 위한 병렬연결에 적용할 수 있을 것이다.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.522-529
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• 2010

Distance relay plays an important role in the protection of transmission lines. The application of flexible AC transmission systems (FACTS) devices, such as the static synchronous compensator (STATCOM), could affect the performance of the distance relay because of compensation effect. This paper analyzes the application of distance relay on the protection of a transmission line containing STATCOM. New setting principles for different protection zones are proposed based on this analysis. A typical 500 kV transmission system employing STATCOM is modeled using Matlab/Simulink. The impact of STATCOM on distance protection scheme is studied for different fault types, fault locations, and system configurations. Based on simulation results, the performance of distance relay is evaluated. The setting principle can be verified for the transmission line with STATCOM.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.362-364
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• 1998

The transmission of information by inductive loop is required for train-safety and fast running. FSK modulation has been used for transmission of information in fast running. Transmission channel between train and ground must be protected from interference of power line. To protect transmission data from noises, the analysis on the transmission line must be performed in advance. In this paper, transmission line is analyzed in view of reflection and time delay in both noise and signal.

• Wind and Structures
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• v.27 no.5
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• pp.325-336
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• 2018

The physical infrastructure of the power systems, including the high-voltage transmission towers and lines as well as the poles and wires for power distribution at a lower voltage level, is critical for the resilience of the community since the failures or nonfunctioning of these structures could introduce large area power outages under the extreme weather events. In the current engineering practices, single circuit lattice steel towers linked by transmission lines are widely used to form power transmission systems. After years of service and continues interactions with natural and built environment, progressive damages accumulate at various structural details and could gradually change the structural performance. This study is to evaluate the typical existing transmission tower-line system subjected to synoptic winds (atmospheric boundary layer winds). Effects from the possible corrosion penetration on the structural members of the transmission towers and the aerodynamic damping force on the conductors are evaluated. However, corrosion in connections is not included. Meanwhile, corrosion on the structural members is assumed to be evenly distributed. Wind loads are calculated based on the codes used for synoptic winds and the wind tunnel experiments were carried out to obtain the drag coefficients for different panels of the transmission towers as well as for the transmission lines. Sensitivity analysis is carried out based upon the incremental dynamic analysis (IDA) to evaluate the structural capacity of the transmission tower-line system for different corrosion and loading conditions. Meanwhile, extreme value analysis is also performed to further estimate the short-term extreme response of the transmission tower-line system.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.63-65
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• 2006

These days, it is not easy to construct the transmission line because of the environmental association activity, a civil appeal, etc. To solve these kinds of difficulties, the program with leading-edge IT technology, such as GIS, 3 dimensions CAD, computer graphic, etc., is developed to be more transparent and objective in the design stage of the transmission line and the selection stage of the transmission line route. Comparing this program with previous methods, this program is composed of the environmental evaluation program, data producing program for analysis and selecting line route program because it is not possible to conduct those kinds of work without any help from the computer and well-developed program. To confirm the performance of the program, the result from the program and the human were compared. Therefore, the result from the program was same as the result conducted by human. In addition, the program makes the selection of the transmission line route easier by checking the mountainside, lumbering, the estimated cost of the tower construction, etc. in real-time.

• Structural Engineering and Mechanics
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• v.76 no.2
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• pp.251-267
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• 2020

Transmission tower-line systems have come to represent one of the most important infrastructures in today's society. Recent strong earthquakes revealed that transmission tower-line systems are vulnerable to earthquake excitations, and that ground motions may arrive at such structures from any direction during an earthquake event. Considering these premises, this paper presents experimental and numerical studies on the dynamic responses of a 1000 kV ultrahigh-voltage (UHV) transmission tower-line system under different seismic incidence angles. Specifically, a 1:25 reduced-scale experimental prototype model is designed and manufactured, and a series of shaking table tests are carried out. The influence of the seismic incidence angle on the dynamic structural response is discussed based on the experimental data. Additionally, the incidence angles corresponding to the maximum peak displacement of the top of the tower relative to the ground (referred to herein as the critical seismic incidence angles) are summarized. The experimental results demonstrate that seismic incidence angle has a significant influence on the dynamic responses of transmission tower-line systems. Subsequently, an approximation method is employed to orient the critical seismic incidence angle, and a corresponding finite element (FE) analysis is carried out. The angles obtained from the approximation method are compared with those acquired from the numerical simulation and shaking table tests, and good agreement is observed. The results demonstrate that the approximation method can properly predict the critical seismic incidence angles of transmission tower-line systems. This research enriches the available experimental data and provides a simple and convenient method to assess the seismic performance of UHV transmission systems.

• Journal of KSNVE
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• v.6 no.1
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• pp.89-95
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• 1996

If the transmission line voltage is greater than 500kV, audible noise (AN) and hum noise (HN) due to corona discharges on the conductor would be an important design factor for the conductor selection of transmission line. Also there is an aeolian noise: wind noise(WN) from the tower and the conductor due to wind. This paper presents the results of a statistical analysis of audible noise, hum noise, aeolian noise of 6-480mm$^{2}$ conductor bundle in KEPRI 765kV Test Transmission Line which was constructed to develop 765kV double circuit AC transmission line for the first time in the world. The result of the analysis shows that 6-480mm$^{2}$ conductor bundle and tower satisfy configuration the audible noise design criterion of 50dB(A).

• Applied Microscopy
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• v.44 no.2
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• pp.74-78
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• 2014

Dislocation density and distribution in epitaxial GaAs layer on Si are evaluated quantitatively and effectively using image processing of transmission electron microscopy image. In order to evaluate dislocation density and distribution, three methods are introduced based on line-intercept, line-length measurement and our coding with line-scanning method. Our coding method based on line-scanning is used to detect the dislocations line-by-line effectively by sweeping a thin line with the width of one pixel. The proposed method has advances in the evaluation of dislocation density and distribution. Dislocations can be detected automatically and continuously by a sweeping line in the code. Variation of dislocation density in epitaxial GaAs films can be precisely analyzed along the growth direction on the film.