• Current Optics and Photonics
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• 제1권3호
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• pp.196-202
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• 2017

Corona discharge is always a sign of failure processes of high-voltage electrical apparatus, including those utilized in electric railway systems. Solar-blind ultraviolet (UV) cameras are effective tools for corona inspection. In this work, we present an automatic railway corona-discharge detection system based on solar-blind ultraviolet detection. The UV camera, mounted on top of a train, inspects the electrical apparatus, including transmission lines and insulators, along the railway during fast cruising of the train. An algorithm based on the Hough transform is proposed for distinguishing the emitting objects (corona discharge) from the noise. The detection system can report the suspected corona discharge in real time during fast cruises. An experiment was carried out during a routine inspection of railway apparatus in Xinjiang Province, China. Several corona-discharge points were found along the railway. The false-alarm rate was controlled to less than one time per hour during this inspection.

• Smart Structures and Systems
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• 제16권3호
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• pp.383-399
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• 2015

Today, as railways increase their capacity and speeds, it is more important than ever to be completely aware of the state of vehicles fleet's condition to ensure the highest quality and safety standards, as well as being able to maintain the costs as low as possible. Operation of a modern, dynamic and efficient railway demands a real time, accurate and reliable evaluation of the infrastructure assets, including signal networks and diagnostic systems able to acquire functional parameters. In the conventional system, measurement data are reliably collected using coaxial wires for communication between sensors and the repository. As sensors grow in size, the cost of the monitoring system can grow. Recently, auto-powered wireless sensor has been considered as an alternative tool for economical and accurate realization of structural health monitoring system, being provided by the following essential features: on-board micro-processor, sensing capability, wireless communication, auto-powered battery, and low cost. In this work, an original harvester device is designed to supply wireless sensor system battery using train bogie energy. Piezoelectric materials have in here considered due to their established ability to directly convert applied strain energy into usable electric energy and their relatively simple modelling into an integrated system. The mechanical and electrical properties of the system are studied according to the project specifications. The numerical formulation is implemented with in-house code using commercial software tool and then experimentally validated through a proof of concept setup using an excitation signal by a real application scenario.

• Proceedings of the KSR Conference
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1229-1234
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• 2009

The rolling stocks of KORAIL are KTX, Saemaulho Multiple Unit(PP), New Electrical Locomotive(DL), Electrical Locomotive(EL), Diesel Locomotive, Metropolitan Commuter Train(CDC), VVVF and Resistance Controlled Multiple Unit, etc. EMU with the maximum speed of 150km/h is under the test run at the moment. Electrical Multiple Units for mainlines with 180km/h speed are supposed to be introduced as a substitute for Saemaulho Multiple Unit which is scheduled to be out of service. But the specification standard for the control board design of train driver's cab does not exist and there is no a study for layout and type of controlling device with driver's ergonomical approach. That's why the types of controller and operating are different from rolling stocks, which has high possibility of driver's human error and needs education whenever a new car comes in. Based on the opinion poll of drivers, design specification of safety engineering and ergonomics for controlling devices and safety facilities can improve exact control for devices and deal quickly with an emergency so as to improve rolling stock safety and operational efficiency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제20권12호
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• pp.1093-1098
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• 2007

Tilting trains are currently in operation in 13 countries around the world. With the advances in tilting technology, verification of economic efficiency, and changes in economic situations, the introduction of tilting trains will rapidly spread across the globe. The measurement system is composed of the industrial computers installed in the console and the measurement racks mounted on each car. It is utilized to accumulate the data by the communication card and the optical cable. The optical cable and power cable are coupled at the connector located in joint of train to make easy to disconnect car each other. The signal conditioner is designed to choose and to extend the channel for each sensor readily. The sensor measurement rack has adopted as decentralization method. It is installed in each car to minimize the cable length. In also, it is manufactured based on 19"rack and covered to protect the cable. In this study, the programs for measurement and analysis were also developed to understand the traction system characteristics of TTX. Using this measurement system, we studied that acceleration test, re-powering test, and gradually powering test. The acceleration performance of TTX is 1.735 km/h/s, and it is inner standard value. The notch test result from 1 to 7 steps, DC link voltage is under standard value, and the output electric current of inverter is controlled normally. From the test results, we saw the performances of the traction systems are normal.

• Journal of the Korean Society for Railway
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• 제14권4호
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• pp.364-369
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• 2011

For the safety management of tunnel, effective measurements should be continuously carried out. Most of sensors currently being applied for tunnels measure only the local status, thus many of them are needed to monitor an entire tunnel. For the railway tunnel where trains of same conditions are regularly operated, dynamic responses of tunnel structure to train operations can be a good index to estimate the deformation of tunnel structure in wide area. Meanwhile, the electromagnetic interference caused by overhead centenary in railway tunnel obstructs the use of electric-based sensors. In this study a brand new accelerometer using FBG optical fiber sensors is developed to solve these problems. Sensitivity and capacity of the accelerometer are enhanced with effective structural design of its components and verified with laboratory tests. A case history where the developed accelerometers were applied to a safety monitoring system of a high-speed train tunnel is presented. The performances of the developed accelerometers are validated from the measured acceleration data.

• Journal of the Korean Society for Railway
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• 제14권2호
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• pp.109-115
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• 2011

The shoe brake of the KTX is used in low speed when the electric brake is not effective. The main purpose of the shoe brake is to stop the train to a desired stop point at the station. Lots of defects have been encountered in the shoe brake unit since the KTX started its operation. To improve the reliability of shoe brake unit of the KTX power car, first of all, failure modes of the KTX shoe brake unit were analyzed. Main failure modes are cracks in the shoe friction material and fracture in the welded joints of the shoe backing steel structure. Several methods to remove the defects of the shoe brake unit were proposed and on-board tests were carried out: Increase of the strength of the shoe key and shoe cam, which decreased a little the occurrence of cracks in the shoe friction material; Redesign of the shoe backing steel structure, which eliminated the occurrence of the cracks in the backing plate but could not solve completely the crack problem in the shoe friction material; Development of a new friction material, which with redesign of the shoe backing steel structure could solve satisfactorily the crack problem in the shoe friction material.

• The Journal of the Korea institute of electronic communication sciences
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• 제13권6호
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• pp.1161-1168
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• 2018

On April 27 2018, North-South Korea agreed to establish the practical methods for connecting the railway in the inter-Korean summit talks. This is often reported that the train will be operated directly between Busan and Europe. However, there are many problems for the railway to directly connect between Busan and Europe. Because a train from Busan to Europe should pass through North Korea, China or Russia, and each national railway systems are different. Thus, South Korean railway has to study thoroughly an interoperability before railways directly operates between a nation and another. The standards and technical harmony for direct connection with a different railway network is very important, because a rail transport is a total network system. This paper surveyed a European railway interoperability and studied on the basic direct operation for the North-South Korean railway systems.

• Proceedings of the KSR Conference
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1681-1698
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• 2011

According to the demands of the times, Inchon international airport railroad opened up step by step but It is situation that much government subsidies are paid because It does not competitive power with road traffic by decline of schedule speed. Inchon international airport railroad users will convert by other transportation and minimize damage their time as travel time is prolonged. Therefore, need high speedization of airport railroad, this may act big role competitive power security as well as airport railroad activation with another public transportation. Thus, this paper suggests that a high speedization possibility section in the sections of airport railroad and train speed elevation effect analysis by roadbed, railroad, system improvement and the most efficient operation intervals analyzing each vehicles (AREX (120km/h), KTX (230km/h), EMU(Electric Multiple Unit, 180km/h) train running pattern.

• Journal of Korean Society of Steel Construction
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• 제17권6호통권79호
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• pp.681-688
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• 2005

This study investigates an existing steel plate girder railroad bridge after superstructure rehabilitation to monitor static and dynamic responses using Fiber Bragg Grating (FBG) sensors. This paper also presents an experimental technique to estimate the vertical deflection of the bridge using FBG sensors. Seven FBG sensors are multiplexed in a single optical fiber and installed in parallel pairs along the length of the bridge, with one set at the top flange and the other at the bottom flange. In addition to FBG sensors, a conventional electric strain gauge and anLVDT are installed at the mid-span of the bridge for comparison. A test train consisting of one locomotive is placed at the center of the bridge to produce the maximum static effect. The train is also made to pass over the bridge at different speeds ranging from 10 km/h to 90 km/h to monitor the dynamic response of the bridge. This study demonstrates that the measured strains using the FBG sensor compared well with the readings from the electric strain gauge. The results show that the proposed instrumentation technique is capable of estimating the vertical deflection of the bridge for various loading conditions, which is crucial in structural health monitoring. Several dynamic characteristics of the bridge were also identified.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제19권11호
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• pp.350-356
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• 2018

The contact force, which is the dynamic interaction between the pantograph and the catenary, is an important indicator for evaluating the current collecting quality, which is a stable power supply characteristic to the vehicle. In this study, dynamic contact force characteristics of pantograph of HEMU-430X vehicle, which is a power-distributed high-speed train test vehicle, were analyzed according to the catenary tension and compared with the analytical results using the pantograph-catenary interaction model. As a result of comparing the test results with the analytical results, it was confirmed that the average contact force and the standard deviation of the contact force, which are the main dynamic contact force characteristics, coincide relatively well. Using the analytical model, the relationship between the catenary tension and the contact force is presented according to the vehicle speed, and the optimal catenary tension for each operation speed is presented and compared with the international standard. As a result, it was found that the results obtained from the analysis are comparable to those recommended by international standards.