• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1256-1261
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• 2015

Along with the increase of railway catenary system operation speed to 400 km/h, there have been growing demands for good quality current collection systems that satisfy quality standards as well as criteria for safe working. Retaining uniform elasticity tension of contact wires is essential in maintaining high quality contact between pantograph and OCL (Overhead Contact Line) of current collection systems in high speed railways. Therefore, the tension of contact wire must be kept within tight tolerance limits in both working conditions and adverse weather conditions of catenary system. In accordance with these conditions, this paper presents a real time monitoring system for the tensioning device of the newly installed catenary system on the special route of Honam high speed line for 400 km/h operation. For the verification of the true value of tension of contact wires, we have developed ring-type tensioning sensors which were installed on supporting points of mast which compose the catenary system. According to the field test performed on the Honam high speed line catenary system, variation of tension was measured accurately in real-time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2171-2175
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• 2011

The objective of this paper is to discuss technologies on assessing reliability of arc detectors by composing a system that generates and simulates occurrence of arc caused by loss of contact between pantographs and contact wires in a laboratory condition. In order to establish the arc simulator, a device that generates light having the bandwidth of arcs that occur between carbon-metal. The simulator was designed under conditions of EN 50317 and simulations were conducted using the developed device. According to the results, it was possible to conduct certification tests following regulations of international standards and the precision of the simulator was satisfactory. The proposed arc detector assessment system is expected to enhance precision of current collection quality performance assessment methods at high-speed lines and conventional lines while being referred as fundamental technologies for development of detectors suiting international conditions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.868-871
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• 2008

We propose an optical-based measuring instrument of catenary system in electric railway. This system was made to utilize line scan camera as inspecting system to measure the stagger and height of overhead contact wire in railway and composed with optical type source and FPGA-based image acquisition system with PCI slot. Vision acquisition software has been used for the application to programming interface for image acquisition, display, and storage with a frequency of sampling. To check the validity of our approach for the intended application, we monitored height and stagger in the overhead wire of a high-speed catenary system in Korea. The proposed optical-based measuring instrument to measure the contact wire geometry such as the hight and stagger shows promising on-field applications for online condition motoring. We expect that a new generation of real-time instruments with demanding various conditions motoring requirement in railway can be easily integrated into optical-based measuring instrument system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1659-1665
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• 2015

In general, AT(Auto-transformer) is used to improve voltage sag and inductive interference in power lines and communication lines in AC electrical railway feeding system. Especially, Korean AT feeding system has different composition compared to other countries like Japan or France, so that it has some special characteristics. However, relays imported from other countries have been used in Korea, and settings of these relays should be modified and reflect distinct characteristics of Korean AT feeding system. Therefore, study about fault analysis based on modeled AT feeding system is important. In this paper, we modeled a single track AT feeding system by using PSCAD and analyzed fault current flow in case of trolley-rail short circuit fault. Finally, we presented current magnitude of each branch expressed by boosting current of AT.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.975-980
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• 2017

Overhead catenary system of electric railway has overlap sections which devide and tighten trolley wire supplying electric power to train, where current collection performances may become worse according to railway speed-up. Current collection tests conducted at 400 km/h test-bed section of Honam high-speed railway show that balanced line arrangement at overlap section is needed to secure current collection without arc generation between trolley wire and train current collection device. This paper proposes a design procedure of the overlap section to allow for tension increase and uplift of the trolley wires according to railway speed-up. By applying the proposed procedure to the overhead catenary system of Honam high-speed railway, it is suggested that the minimum span length should be 33.2 m for railway speed-up to 350 km/h and 43.7 m for speed-up to 400 km/h.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.65-70
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• 2015

Lightning is one of hazards affecting the rapid-transit railway system. There are two effects, which are direct lightning surge to electric car line and induced lightning surge. Protection methods for the direct lightning surge are studied with various occasions, however, study of induced lightning surge is insufficient in spite of a large or small effects. In this paper, it is analysed the way that serge voltage is induced to electric car line by lightning strikes. By modeling the propagation process and the coupling phenomenon of electromagnetic wave produced by lightning strikes, it is achieved to make integrative circuit model combined with existing electric car model. The study is conducted into three different waveform of electromagnetic wave produced by lightning; rectangular wave, double exponential distribution wave, triangle wave. It is also simulated that the inducing serge is coupled to electric car line in an arbitrary location. The simulation results in that, when rapidly changing rectangular wave is supplied, maximum power is induced to electric car line.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.10
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• pp.1517-1522
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• 2015

Since electric railroad vehicle pass through repeatedly on the railroad bridge, the dynamic load that causes the change of tension of contact wire affect it constantly. In this paper, we measured the dynamic displacement of the railroad bridges to analyze the effect of tension in the catenary. A result of dynamic measurement of the longitudinal displacement, it's maximum value was 39.9mm which was lower than the primary management criteria 378mm. Also on the based of a maximum temperature, it shows a feature that the longitudinal displacement value increased as temperature rise from April to October. In terms of behavior characteristics of a tensioning device, it was confirmed to be the value of 50mm stroke movement when the temperature changes ±5℃.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.10
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• pp.1501-1507
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• 2015

The contact wire pre-sag in railway overhead catenary has been considered as a innovative idea which improves the current collection quality and is expected to evenly distribute wear along a span. However, long term studies on the effects of pre-sag, especially on the quantitative wear pattern of the contact wire, have not yet been reported. Therefore, in this study, the pre-sag and wear pattern of the contact wire along a span from long term operation of railway in Korea was surveyed. The examination was conducted on 3 lines, the Gyeongbu high-speed line with pre-sag of span/2000, the Gyeongbu existing line without pre-sag, and Gyeongchun line with pre-sag installation on 1/1000 of its span. The wear measurements of 58 sample spans were examined. The wear pattern analysis show no interrelationships between pre-sag and evenly distributed wear, but more wear occurred at the center of a span compared to the ends of the span, especially more noticeable as span length increases.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1618-1625
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• 2015

The reliability of catenary system is very important for uninterrupted train operation as it supplies electric power to train without redundant facilities. This paper provides a systematic approach to the reliability analysis of the catenary system based on FMECA procedures defined by global standards such as MIL Std 1692a and IEC 60812. Field failure data collected from the operation and maintenance of high-speed railway catenary system for 9 years are used to derive critical failure modes and to evaluate the criticality of the failure modes. Evaluation of the criticality are carried out by quantitative procedures defined by MIL Std 1692a and by criticality matrix defined by IEC 60812. FMECA results suggests that three critical failure modes should be checked carefully during maintenance work, which include strand break of dropper and voltage equalizing wire, power supply failure of feeder. Maintenance procedure of catenary system in order of importance is suggested too. These results can be applied to maintenance planning and design of catenary system to improve the reliability of electric railway system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.601-602
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• 2005

In the cold and temperate regions of Korea the icing and ice coats on 25 kV overhead contact wire during winter is a very serious problem. This generates shocks at the mechanical interface of the collecting strips of the pantograph and the contact wire and extra electrical resistance, which may affect quality of current collection at the contact wire / collecting strips of pantograph interface. De-icing operations should be performed just before train operation to avoid the formation of another ice layer. This paper presents temperature analysis of the de-icing system which could be applied to the overhead contact wire of railways.