• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1818-1823
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• 2015

In this paper, we analyzed the optimal configuration of protection wire that have been installed in the electric railway power supply system. Protection wires are to suppress the ground potential rise when the short circuit fault between contact wire-rail(C-F), and protect the electronics equipments(signalling and communication) that are facility the wayside. The role of protection wires must be feed back quickly the fault current to the substation when a short circuit fault occurs. In this paper, we proposed that only one line to install the protection wire. Comparing how to newly proposed and existing system, most of the performance is similar. The reason is that most of the current flowing in the protection wire near the location where the fault occurred. There is no problem even if in one line for human safe and the low impedance of the return circuit in dimension to ensure the safety of the facility during the fault. To ensure safety during an fault occurs, it is sufficient even by one line. But, In the protection wire of facilities planning it is necessary to design taking into account the potential utility.

• Journal of the Korean Society for Railway
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• v.6 no.4
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• pp.279-285
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• 2003

In an electric traction system in which power is supplied from a catenary via a pantograph, the mechanical design of the catenary and pantograph is clearly of importance in relation to the problem of current collection at high speed. A computer-simulation technique is used to study the effects of changing parameters of pantograph and catenary on the quality of current collection at high speed. The current collection system is evaluated on the basis of the contact-force variations and displacement responses of the pantograph and contact wire. This study shows that current-collection quality is determined primarily by the overhead line parameters rather than by the pantograph. The results can be applied to optimize the design of current-collection systems.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.3
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• pp.383-389
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• 2016

Kissing of sub-conductors due to magnetic forces has been investigated in a 154 kV bundled overhead transmission line. With increasing ampacity of the conductors and enlarging the distance between spacers, lager magnetic force was measured. When the phase ampacity was 2,000 amps and the distance between two adjacent spacers was 68 m, for instance, the conductors became unstable and vibrated with a frequency of several herts. Furthermore, when the ampacity was 2,250 amps and the distance between spacers was 136 m, the two sub-conductors were contacted. Analysing the magnetic forces with distance of spacers, the safe distance of spacers to avoid contact of sub-conductors was presented. The change of the safe distance is discussed due to various parameters, such as residual stresses and wind pressures, in the real transmission lines.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.663-669
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• 2009

In the electrical railway, the increase of tensions in an overhead contact lines is essential to speed-up of train, because current collection quality largely depends on the ratio of a wave propagation speed to a train speed. For Kyungbu high-speed line, a pulley-type tensioning device is required to have a tension variation of maximum 3%. Therefore we developed a pulley-type tensioning device in order to meet tension variation requirement of the high-speed tensioning device. To verify the performance of the developed device, a performance test, overload test and failure test were carried out according to the factory test procedure of the Kyung-Bu High-speed line. Furthermore, we also performed reliability performance through not only a fatigue test in a factory, but also on-line verification test in Chungbuk line for over 1 year. These tests verified that the tensioning device had applicability to a main line.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1444-1452
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• 2011

At present, Kyungbu high-speed railway is operated with 300km/h, Honam high-speed railway is being constructed with 350km/h, and the development for the overhead contact line system is to be conducted for the next-generation high-speed railway with the speed of 400km/h. It is necessary to set up the specification and criteria for the key parts such as dropper, termination clamp and tension insulator for the 400km/h railway line. In this paper, the specification and the criteria for dropper, termination clamp and tension insulator has been reviewed and proposed in order to secure long-term reliability and stability under the maximum speed of 400km/h. Also, the specification, criteria and international standards for 300km/h class and 350km/h class railway line system and the international standards related with the insulators have been reviewed, compared and analysed.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.137-139
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• 1993

This paper details methods used to verify the adquacy of a dc traction power supply for design in Seoul matropolitain subway Line-6 system. Examples of the approach are given for a major subway presently under construction. The performance of trains operating at maximum system design capacity is modelled using a train simulation program. Using a dc network analyser program, the maximum train operating timetable, and a model of the ac and dc electrical suppy system, the electrical performance of the entire system can be modelled over a 24-hour period. The results of this analysis are used to determime: train voltage at a level sufficient to ensure train schedules: adequacy of traction transformers, rectifier, and switchgear ratings; sizes of the overhead contact systern conductors, and ac and de feeder cables: and power and energy demands at the utility company's supply points for inital and final timetable operations.

• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.447-453
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• 2012

It is studied that the structure of the contact plane geometry of the contact wire would be changed when the contact wire tension is increased in the existing overhead contact lines for the purpose of improving the operation speed temporarily. In this paper, the dropper length formula which could be well applied to the pre-sagged catenary is reviewed first. Second, the changing amount of the pre-sag if the contact wire tension change from 20kN to 23kN or from 20kN to 25kN for the Gyeongbu HSL(high speed line) 49.5m catenary is evaluated by using of the self-written program in accordance with the dropper length formula. Moreover, the increasing tension and measuring the pre-sag change experiment in the Gyeongbu 2 HSL was conducted. The calculated data are compared with the measured data. As a result, it is found that the geometry change is very little and will not make the current collection performance deteriorated.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.198-201
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• 2001

Recently the wireless-internet has been spreading extensively. People are spending a large part of their time gaining access to information using a mobile device. With the rapid growth of on-line Electronic Commerce, the use of mobile devices creates a new paradigm that provides users with location-independent real time service. Although this new paradigm does have some advantages, limited process speed, low bandwidth, the low battery capacity of mobile devices, and a high rate of wireless network errors causes many overhead expenses during service time with the server. In this paper, we suggest an autonomous service delivery system, which provides mobile agent capability to users that cannot maintain a connection. We have developed the system based on java mobile agent technology. Using this system, we can provide more effective service to users when the user is sending requirements for service through a mobile device that has limited resources. Furthermore we can manage the contact server dynamically when new services are added.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.972-977
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• 2009

For the improvement of a train speed in the conventional line from overhead system point of view, it is necessary to approach not only in the aspect of the increasement of tension for catenary but the application of a pre-sag. A certain tension acting on a dropper is removed when it is slack by the pantograph passing. Right after the pantograph passes, the dynamic force caused by the mass of contact wire acts on the dropper. If the pre-sag is applied to the catenary, the static force on the dropper is increased. For the assurance of the safety for the dropper, it is necessary to predict the dynamic force. The purpose of this study is to predict and analyze the force on the dropper according to the applied pre-sag.

• 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.