• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1155-1161
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• 2017

This study examines environmental performance of the arcing measurement module according to international standards. The module assesses the collected current performance using a computer system. The module is required to assess environmental impact resulting from electromagnetic waves, shock and temperature change during train operation. The test includes testing EMI/EMC, vibration, shock and temperature cycling for interface between trains and the arcing measurement module. The module test items were determined in compliance with the standards suggested by the International Electrotechnical Commission (IEC) and Europaische Norm (EN). This study describes the method of test, test equipment operation and how to choose relevant performance standards. The analysis and test results of environmental performance for the module based on computer system are described in this study.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.855-859
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• 2014

Quality criteria for interaction between a pantograph and overhead contact wire is a most important requirement to assess of the performance for the current collection system. Interaction performance between pantograph and catenary system is subject to approval by the infrastructure manager when a new design and contraction of overhead contact line and pantograph are installed. Among the various performance, percentage of arcing at maximum line speed is a simple test method compared with contact force of pantograph due to direct sensing of pantagraph, calibrations, installations of train, and etc. On the other hand, percentage of arcing is need to reliable arcing detector and general requirements with accordance with EN 50317. In this paper, percentage of arcing are investigated on the function of duration of arc and proposed which is satiable of percentage of arcing. As a results, we proposed which duration of arcs are unsuitable from infrastructures point of view as performance testing for quality of current collection.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.7
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• pp.976-980
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• 2018

The traction power system is configured to transmit electricity to the vehicles through mechanical contact between the OCL (Overhead Contact Line) and the pantograph. The system measures the current collection performance of the OCL, or the OCL installation condition is examined through maintenance for commercial operation. Maintenance continues to check the conditions through visual inspection by walking and inspection vehicles. The current collection performance is divided into the percentage of arcing(%), the contact force, and the uplift. The percentage of arcing is composed of a vision based system and used to verify the performance of a new OCL. However, it is not always possible to measure the current collection performance during commercial operation, and maintenance based on human resources can not be replaced. This paper presents the minimum performance condition of video devices in the current collection system of commercial vehicles. In addition, a continuous arcing was measured, and current collection performance was examined on the traction power system at the 250 km/h. It was analyzed with a minimum duration of arc of 1 ms. The frame rate is then shown by comparing the number of frames in the image at the time intervals of the number of the arcing. It is expected that the result of this study can be used for examining the minimum performance of video devices depending on their purpose.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.468-479
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• 2016

In order to supply power to online monitoring systems that are attached to high voltage catenary or overhead wires, a wireless power transfer system is required that is able to transmit power over the insulation gap. Such wireless power transfer systems have transmitter and receiver coils that have diameters of over 10cm. This paper focused on an investigation of the sources of loss in the coils when the coils are fabricated using printed circuit board technology. Using finite element simulation results, it has been shown that the dielectric loss in the substrate was the dominant source of the total loss. It has been demonstrated that the selection of a proper dielectric material was the most critical factor in reducing the loss. For further reduction of the loss, the distributed tuning capacitor method and the slotting of the inter-turn spaces have been proposed. For the evaluation of the proposed methods, four coils have been fabricated and their equivalent series resistances and quality factors were measured. Measured quality factors were greater than 300, which means that these devices will be helpful in achieving high coil-to-coil efficiency.

• 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.62 no.12
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• pp.1820-1823
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• 2013

An overhead catenary system is the one of the main subjects for increasing speed in electric railway. When a vehicle increases the speed over 350km/h, vibrations and wave propagation reflections occur severely. Therefore, the system suitable for the speed are needed. A wave propagation speed of contact wire is the main criteria to determine the tension for the system. Therefore, a train speed is restricted below 70% of wave propagation speed of it in European railway code. In this study, we measured a strain and uplift of contact wire while HEMU-430X tain is operated for the speed-up trial test in Kyungbu high-speed railway. The measured strain and uplift are analyzed with wave propagation speed according to the speed-up. The more a train speed reaches to a propagation speed, the more measured strain is high. Through the study, an experimental approach is performed about the code which a train speed is restricted below 70% of wave propagation speed of it.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.507-511
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• 2019

The purpose of an electric railway system contact wire is to supply electric energy to trains through a contacted pantograph. This energy is then converted into mechanical energy. Recent developments in overhead contact lines include the increase in the tension force up to 34 kN according to train speeds that reach up to 400 km/h with a verified safety. Rigid conductor catenary (R-Bar) for high speeds of up to 250 km/h have been developed in tunnels to save on construction costs. This is significant because minor defects in R-bars in aspects, such as height and stagger affect installation conditions. In this study, we propose the use of a detector that measures the static characteristics to reduce the R-bar installation errors. This detector has been developed to measure the height and stagger of the contact wire using video images.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.222-227
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• 2011

The dropper supports the contact wire and is attached using various types of dropper clips on the catenary. Droppers are subject to mechanical stress from buckling during the passage of pantographs. In order to investigate failure causes for the high speed line dropper, theoretical analyses and experiments have been carried out. In this paper, mathematical formulas are derived for the pre-sag of the dropper static load. The measured values in the experiment were similar to the theoretical predictions. To analyze the cause on fracture of dropper wire, we have conducted analysis such as SEM(Scanning Electron Microscope) of fractured specimens in the field and new specimens. Finally, we performed measurement for the variation of dynamic load on the dropper when a pantograph moved at 300km/h under the Korean high speed overhead line. If such mechanical load occur repeatedly with every passing pantograph, it is possible that the dropper wire will break due to fatigue. This results will be used for special management of high speed catenary system maintenance and life estimation of dropper.

• Journal of the Korean Society for Railway
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• v.17 no.1
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• pp.7-13
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• 2014

Stiffness variations and wave propagation/reflection in railway catenaries are the primary sources of contact loss between a pantograph and a railway contact wire. This paper analyzes which design parameter is more important for 200km/h conventional rail and 300km/h high-speed rail, in order to effectively reduce the contact loss. For the high-speed rail, the wave propagation and reflection in the overhead contact lines are more influential than the stiffness variation over a span. When the high-speed rail needs to speed-up, it is necessary to develop higher strength contact wires in order to increase the wave propagation speed. In addition, the dropper clamp mass should be reduced in order to alleviate the wave reflection. However, it is noted that the increase in the tension to a messenger wire could deteriorate the current collection quality, which contrasts with expectations. For the 200km/h conventional rail, the stiffness variation over a span is more influential than the wave propagation and reflection. Therefore, shortening span length, increasing the tension in the contact wire and optimizing the location of the droppers are recommended for a smoother stiffness variation over the span.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1742-1746
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• 2014

In order to develop a overhead catenary system for the maximum speed of 400 km/h on Honam high-speed line, increasing tension of contact wire, changing dropper distributions, reducing a hard point and etc. should be considered. And it is also essential to develop core components taking account of the increased tension. Therefore we developed a new steady arm for the max. speed of 400 km/h in this study. FEM (Finite Elements Method) analysis was performed to ensure the strength of the arm. An oval shape was applied to the arm, so that 25 % of strength was increased and 9 % of weight was decreased. And a type test according to the code KRSA-3012 was performed to ensure the performance. Fatigue test in KRRI (Korea Railroad Research Institute)'s test-bed was also performed to evaluate its performance. Some section of the Honam High-speed line was constructed with the developed steady arm.