• Proceedings of the KSR Conference
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• 2009.05a
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• pp.900-904
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• 2009

The measurement of contact wire uplift in electric railway is one of the most test method to accept the maximum permitted speed of new vehicles or pantographs. The contact wire uplift can be measured for shot periods when pantograph is running in monitoring station. This paper describes the development of two different methods for contact uplift measurement using vision-based system and wireless online monitoring system. Our vision-based system employs a high-speed CMOS (Complementary Metal Oxide Semiconductor) camera with gigabit ethernet LAN. The development of a real-time remote monitoring system that acquires data from any kind of sensor to be transmitted by wireless communication from overhead line and structure at 25 kV to a computer in catenary system. The proposed two kind of different measurement systems to evaluation for dynamic uplift of overhead contact wire shows promising on-field applications for high speed train such as Korea Tilting Train (TTX) and Korea Train eXpress (KTX).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1352-1355
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• 2004

We have applied front contact metallization of plated nickel and copper for high efficiency passivated emitter rear contact(PERC) solar cell. Ni is shown to be a suitable barrier to Cu diffusion as well as desirable contact metal to silicon. The plating technique is a preferred method for commercial solar cell fabrication because it is a room temperature process with high growth rates and good morphology. In this system, the electroless plated Ni is utilized as the contact to silicon and the plated Cu serves as the primary conductor layer instead of traditional solution that are based on Ti/Pd/Ag contact system. Experimental results are shown for over 20 % PERC cells with the Plated Ni/Cu contact system for good performance at low cost.

• The KSFM Journal of Fluid Machinery
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• v.20 no.1
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• pp.35-40
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• 2017

In order to investigate the change of contact force of pantograph pan head due to the change of aerodynamic force, three dimensional flow around the pan head were calculated. For this, the aerodynamic modeling of pan head of CX pantograph was performed and the standard deviation of the contact force of the simulation results were compared with those of the experimental results of wind tunnel tests. From the comparison, it was confirmed that the current grid system and the numerical methodologies can be utilized to calculate the aerodynamic characteristics of the pantograph pan head. By using these grid system and the methodologies, the standard deviations of the contact force of pan head were calculated with velocities as 200, 250, 300, 350, and 400 km/h. The maximum standard deviation of the aerodynamic contact force of pan head was 92 N at 400 km/h and statistical minimum contact force was more than 0 N. Therefore, it was confirmed that and the pan head of CX pantograph was statistically contacted with the catenary system with the train speed of 350 km/h though the aerodynamic contact force was changed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1803-1808
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• 2013

To maintain contact between catenary and pantograph copper is important in order to transmit power smoothly on Current collection system. But, Arc discharge with strong light is generated because of contact loss. Therefore, Arc discharge detection is important measurement factor judging performance of current collection system. In this paper, It is described to results of arc discharge applying UV detection technology using arc generator. And Arc discharge was detected using the most commonly used processing catenary and rigid catenary and pantograph copper of electric rolling stock for securing arc detection instrument reliability. Results of contact loss detection instrument in this paper will be used for maintenance of current collection quality and system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.6
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• pp.474-483
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• 2003

In this study, the dynamic characteristics of a catenary system and pantograph supplying electrical power to high-speed trains are investigated. One of the most important issues accompanied by increasing the speed of high-speed rail is stabilization of current collection. To stabilize current collection, it is necessary the contact force between the catenary and the pantograph to be kept continuous without loss of contact. The analytical model of a catenary and a pantograph is constructed to simulate the behavior of an actual system. The analysis of the catenary based on the Finite Element Method (FEM) is performed to develop a catenary model suitable for high speed operation. The reliability of the models is verified by the comparison of the excitation test with Fast Fourier Transform (FFT) data of the actual system. The static deflection of the catenary, stiffness variation in contact lines, dynamic response of the catenary undergoing constant moving load, contact force, and each state of the pantograph model were calculated. It is confirmed that a catenary and pantograph model are necessary for studying the dynamic behavior of the pantograph system.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.1
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• pp.35-44
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• 1996

A design method for a teleoperator robot system is presented in this paper. The control system consists of two phases; approach phase and contact one. The end-effector position of the estimated slave robot and the contact force between the end-effector and wall are displayed on the monitors at control site, using which the operator controls the teleoperator system. The approach phase controller is designed using Smith's principle and the contact one designed based upon the structured singular value ${\mu}$ in order to increase the robustness of the system. The uncertainatices such as communication time delay and the variations of system parameters are considered as a muliplicative pertubation. Computer simulations are conducted in order to evaluate the performance of the proposed design method. It is found that desirable control performance, especially in the contact phase, is obtained if the control mode is switched into contact phase when the estimated position of the slave robot end-effector is in front of the wall.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1782-1788
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• 2015

In this paper, analysis of the effects for construction tolerances on the current collection performance of high speed catenary system. The height of the contact wire is the geometrical position of the cantilever directly affects the current collection performance. Contact force when the height of the contact wire exceeds the construction tolerance were analyzed. As a result, the maximum contact force was analyzed to more than 350[N] that are recommended by EN50119. And when the geometrical position of the cantilever to exceeds the construction tolerance, the analysis results of uplift at the mast support points, it becomes 127[mm] that are recommended by UIC 799. If the construction tolerances exceeds the reference value, the current collection performance is deteriorated. Therefore, catenary system require high precision construction. In the future, there is a need for continuing research on the tolerance of catenary system in the actual operating state.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6B
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• pp.541-550
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• 2011

This study sets the goal to improve effectively water quality of stream by complementing the weak points of the gravel contact oxidation process to use the inverted siphon curved channel system in free overfall of serial contact materials. The size of the current system can be diminished by expanding contact time, and the materials' replacement can be made easier when their gap are closed through the filtering boxes of contact materials. This system also has been developed into a construction method in which mixed and serial contact materials can be employed by using just the conventional single contact materials. It was verified the improvement ability of water quality of this system, during the simulation test at Tandong stream in Daejeon. The results of the verification of water quality improvement through several experiments in field were measured as follows : it showed to reduce about the averaged 55~83% higher than 60~75%, the internal planned goal of water quality improvement facilities.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2215-2216
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• 2011

In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to electrical railway vehicle is investigated from an electrical response point of view. To analysis voltage and current waveforms by induced contact loss phenomenon on driving electrical railway vehicle, a hardware Simulator which considered contact loss between contact wire and the pantograph as well as contact wire deviation is developed. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system. Throughout prototype simulator and contact wire and catenary wire experiments, it is confirmed that current waveforms is distorted by contact loss phenomenon and in case of driving electrical railway vehicle.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.241-246
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• 1997

Corrugation of railway track can be caused by the various dynamic behaviors of traveling wheels and track. In this paper, the coupled vibrations of traveling wheel and railway track are analyzed as the cause of corrugations. To analyze the coupled vibration, the track supported by the sleepers and the traveling wheels are identified to the elastically supported infinite beam and the spring-mass system which runs at constant speed. The Hertzian contact spring is considered between the infinite beam and spring-mass system. The dynamic responses of elastically supported infinite beam and spring-mass system are calculated. The cause and development of rail corrugation are discussed in the view point of contact force fluctuation affected by the elastic supports and the corrugated surface profile on the track. By the obtained results, the possibilities of resonance are checked between the excitation by the corrugated surface profile and the natural frequency of contact spring-mass system. It may be thought to a development of railway corrugation.