• Journal of the Korean Society for Precision Engineering
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• v.29 no.12
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• pp.1346-1350
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• 2012

Contact wire is one of the most important components supplying electricity to railroad cars. At the beginning of the research on contact wire, wear problem caused by friction between contact wire and pantograph was considered even more important issue for the failure of contact wire. However, since several fatigue fractures were reported from Shinkansen in Japan, fatigue fracture has become another important issue for the failure of contact wire. Despite of its importance, standard of the fatigue test of contact wire has not been established yet. Thus, fatigue characteristics of contact wire is very difficult issue to evaluate quantitatively. Hence, in this study, test method simulating operating conditions of contact wire by Minsung Kang and etc. is used to evaluate the fatigue characteristics of copper alloy contact wire. Also, test results is compared with the result of Minsung Kang's research on pure copper contact wire.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.69-74
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• 2008

The frost and freezing on contact wire in winter is a very serious problem Shocks at the mechanical interface of the collecting strips of the pantograph and the contact wire. Extra electrical resistance, which may affect quality of current collection at the contact wire / collecting strips of pantograph interface. De-icing system is to melt frost or freezing in contact wire. The principle of do-icing system is to melt frost or ice by Joule heat of contact wire impedance. The temperature of the contact wire was increased with increasing the current. But temperature of contact wire was decreased with increasing the velocity of the wind.

• 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 KSR Conference
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• 2006.11b
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• pp.587-592
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• 2006

This paper presents expansion and contraction in accordance with temperature change of contact wire and messenger wire. The tensioning device is designed and installed to pull the contact wire and messenger wire straight at all times. Pulling a contract wire straight ensures that smooth contract is maintained between the contact wire and pantograph of an electric train, and this makes it possible to ensure a stable supply of electricity to the train. Normally, tensioning devices are installed at two positions over a distance of 1.0[km] to 1.6[km] per line. In installing the tensioning device, therefore, it is necessary to study the stroke(the range of the extension/contraction rate of the tensioning device compatible with that of the contact wire and messenger wire due to change in temperature). This paper introduces and discusses this topic.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.15-21
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• 2003

Generally, subway runs under the ground, so it uses rigid contact wire. Pantograph and contact wire, they have effect on the contact force each other. This paper is on the dynamic interaction of a pantograph and rigid contact wire system. For this we developed simulation program of current collecting capability for dynamic interaction for pantograph and rigid contact wire. As a result, we got contact force and displacement between pantograph and rigid contact wire. This paper shows the possibility of better pantograph's suspension design and better maintaining of current collecting capability than present when suspention of pantograph is developed by theoretic result.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.632-637
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• 2010

The measurement of contact wire wear in electric railways is one of the key test parameters to increase speed and maintain safety in electric railways. Wear caused by continuous interaction between pantographs and contact wires has a negative effect on current collection quality and severely damaged contact wires might cause hazardous accidents. This paper introduces a non-contact optical-based contact wire wear measuring system that will replace conventional wear detecting methods conducted by maintenance vehicles or workers. The system is implemented by high-speed cameras that can collect images of contact wires during vehicle operation, a laser used to create images profile of the contact wire surface, and a computer used to process the collected images. The proposed system is designed to assist maintenance of overhead contact lines by creating geometrically plotted images of contact wires to detect contact wire wear during operation on conventional lines or high-speed lines.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1732-1736
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• 2012

To increase speed up of train, in the field of catenary system, it is necessary to develop of new monitoring methods for dynamic interaction between pantograph and contact wire. Also, there is a need to develop technologies that constantly measure are from various railway structure such as uplift of contact wire, vibration of catenary, dynamic strain of contact line in tunnel. In this paper condition monitoring systems for dynamic performance of catenary systems in tunnel were proposed. An advanced method and results of field tests using high speed camera for monitoring of vertical upward movement of the grooved contact wire due to the force produced from the pantograph were presented. The proposed uplift measurement system of contact wire is expected to enhance precision of current collection quality performance assessment methods at high-speed lines.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.157-162
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• 2010

Power line communication, using 25[kV] high voltage of railway catenary, is to provide information which is real-time safety information for train operations and train workers in driving. Lots of noise were occupied in the contact wire by electrical and communication equipments. A signal attenuation was caused characteristics of the contact wire and messenger wire. For relaying communications to transmit information using the contact wire, catenary the noise and signal attenuation were investigated. And the final goal of the study was realized to transmit video information by power line communication on electric railway.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.341-348
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• 2001

In this study, nonlinear vibration analysis of the cylindrical orthotropic porous thin plate under V-shaped tension distribution with wire impact damping is considered. We make dynamic model of the plate under the tension using commercial FEM code and reduce the number of its degrees of freedom using dynamic condensation. The dynamic model of wire is obtained as lumped mass model from string equation. And then we analyze the nonlinear vibration of the plate including the impact phenomenon between the plate and the wire using the reduced mass and stiffness matrices of the plate and lumped model of the wire. The contact phenomenon between them can be described by impact contact elements composed of contact stiffness coefficients from Hertzian contact theory and contact damping coefficients from restitution coefficient between them. And we discussed the results of nonlinear vibration analysis for variations of their design parameters.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.227-235
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• 2007

The railway catenary is softer in the middle of a span than at the end. This stiffness variation induce the vertical motion of a moving pantograph, which results in the large variation of contact forces. To reduce the vertical motion of a pantograph, we can introduce a pre-sag of the contact wire. The pre-sag changes merely equilibrium position of the contact wire. Because the pantograph must follow the sag added to the motion of the contact wire, the sag gives downward forces to the pantograph. If the pre-sag is proper, the variation of the vertical motion of the pantograph is reduced. However, excessive sag worses the current collection performance because the pantograph receives too large downward forces by the contact wire. The objective of the paper is to establish the theoretical basis to understand how the pre-sag affect the contact force variation and to propose the proper sag for the railway catenary for the train speed up to 200 km/h.