• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2168-2174
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• 2009

Electrical railway system consists of rolling stock, track, signal and streetcar line system. Track circuit system is a vital system due to checking the location of trains. Track circuits are divided by using frequency and isolated electrically. Currently, there is not a regulation for the distance between track circuits using identical frequency. In case of installing additional track circuits in large stations or marshalling yard, the problem which is that the signal is not exactly transmitted to the track circuit occurs due to the mutual interference. In other words, the track circuit properly is not operated on account of wrong induction current by the mutual inductance between track circuits. In this paper, we suggest the electrical model between track circuits and numerically calculate demanded parameters in electrical model. The distance between track circuits satisfying the mutual inductance which does not happen to the mutual interference phenomenon is presented about the distance of track circuit. It is proved by using Matlab and PSpice program as the amplitude of mutual induced current.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1701-1706
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• 2007

Jointless AF(Audio Frequency) Track Circuit is more comfortable than exist joint track circuit. This electrical circuit's function is detection train on rail, and transmit information between wayside and vehicle. 'Korea Railroad Corporation' proposed for revision of the Korean railway standards(KRS SG 0038-06 R, 2006.5.16) "Non-insulated AF Track Circuit". This proposal equipment developed to extend use for station of National Railway exist line. According to test standards Korean railway safety law and its ordinances, which were committed to Korea Railroad Research Institute, the professional committee 'Railway facility sector II' have helded on January in 2007. In this investigation, the changed test norm will be review the difference of important function test standards of new version to conform effectivity and safety test procedure according to the KS A 1025.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.879-891
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• 2009

Impedance of rails is increased by the magnetic coupling between rails and reinforcing bars in the concrete slab track. Currently, the current of track circuit has been compensated by installing the compensation capacitors on track circuit because of increasing the impedance of rails. In case of a rapid transit railway, the compensation capacitors are installed every 20[m] to compensate the current of track circuit in the concrete slab track. Because the interval of one block for a rapid transit railway is as long as 1500[m], the compensation capacitors are installed about the number of 70$\sim$75 on track circuit. However, in case the compensation capacitors are broken over the number of three, it is a problem that the amplitude of current is under standard amplitude of current which is 0.8[A]. In this paper, it was suggested installing a compensation capacitor by using resonance phenomenon on the concrete slab track. We represent the electrical model of track circuit and the four terminal network, calculate the parameters demanded for the electrical model in the concrete slab track. Also, we computed the position and capacitance of the compensation capacitor about 2040[Hz], 2400[Hz], 2760[Hz], 3120[Hz] which currently is the track circuit frequency in the Gyeongbu rapid transit railway and demonstrated the validity of it, using the Matlab and PSpice program.

• Journal of the Korean Society for Railway
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• v.18 no.3
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• pp.232-240
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• 2015

Two types of track circuits are used in high speed railway car depots: one is High Voltage Impulse Track Circuit(HVITC); the other is AF track circuit. HVITC detects train occupation of blocks and broken rail; the AF track circuit is used for train onboard control system pretesting before departure. This testing is used to transmit train control information through the AF track circuit. The two systems are switched in turns for testing. We propose a system in which the AF track circuit is replaced by a loop cable that is installed on the inside rail; as such, engineers do not need to switch the systems. In cases in which the two systems run simultaneously, mutual interference may occur. In this paper, we identified this mutual interference by modeling of the two circuits.

• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.500-503
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• 2010

Until now, the track circuit with railroad which is a part of an electrical circuit wad used only for the detection of the train location, but as train speed is up to be higher, in order to overcome the limits of ground signal system the railway signal system has changed from the ground signal system to a cab signal system. The power source of the track circuit has also changed from a direct current or a high voltage impulse to an alternating current with high frequency which is a part of the audio frequency. To improve the maintenanability and according to the environment condition, the railway roadbed is rapidly changed to the ferroconcrete roadbed. In case of a track circuit to use an alternating current with high frequency as power source at a ferroconcrete roadbed, the characteristic of the track circuit is brought on a change from a loss of the magnetic combination instead of a leakage current from electric insulation which was caused by the reinforcing iron pod with lattice shape for durability. This paper is shown the influence and the loss of the signal current at AF track circuit on a ferroconcrete in the simulation sheets and presented a proposal for the preventive method from reduction of signal current.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1709-1715
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• 2011

A track-circuit device exploits two rails as a conductor of an electrical circuit. It detects the presence or absence of the trains with variation of received level when wheel sets of the train shunt rails together. So, it plays an important role in train operation. Non-insulated audio frequency(AF) track-circuit device can separate the rails into tracks by insulated joints without physically cutting the rails. And it transmits AF signals at track boundary, of which frequency is different between adjacent tracks. It has been employed at station-to-station section of domestic high speed rail, general rail, and subway. But It was not used at station yard of complicated general railway where lots of branches exist. In this paper, we consider current development status of non-insulated AF track-circuit device for the use of station yard.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1279-1284
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• 2008

This paper presents the operating characteristic of high voltage impulse(HVI) track circuit owing to the ill-contact of impedance bond lead wire. The characteristic operations of the track include rail voltage and current. Measurements are carried out using oscilloscope with current probe and it analyzed the abnormal operation due to connector of protective wire. Finally, suitable track circuit is proposed for conventional line, and operating characteristic of HVI track circuit is affected by bypass circuit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.147-155
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• 2010

We studied on performance improvement of TTM(TI21 Test Meter) that is test and diagnosis devices for jointless audio frequency track circuit on Korean electric railway TI21 standard. Upgraded devices is AD-TTM(Advanced TI21 Test Meter). This can measure alternating frequency USB(Upper signal band) and LSB(Lower signal band). In the audio frequency track circuit, ${\pm}17[Hz]$ of nominal frequency are demodulated and supplied to track relay through AND gate. It is important that measurement function which is error between USB and LSB. Need of AD-TTM will stand out in the electric railway system because this is simple and accurate rather than the former device.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.195-201
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• 2000

In this paper propose the new method on desig ESJ(Electrical Separation Joint) of Jointless Track Circuit. ESJ has a capability to saparate track signal electrically but enable connected a track section physically. So It is more proper to high-speed line. Because that demand a critical traveling safety and convient taking a train. In spite of existing ESJ of Jointless Track Circuit, UM7l, S-bond, According to new pole-zero placement and desgining tuining-unit It is possible to prove a independence of track-section and track-signal in new ESJ design of this paper

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.5
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• pp.698-704
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• 2012

Electric power used in electrical vehicles flows into the substation through the feedback circuit, track circuit. Due to these power conversion equipments in electrical railroads, return current contains harmonics, and it should not affect other communication lines. In this paper, based on the return currents, we measured harmonics and analyzed an influence in railway equipments due to the harmonics. For analysis, we utilize the measured values of return currents measured in track circuits, and predictive values of those compared to the earth methods between the existing electrified sections. Applying the regulations used for Gyeongbu HSL(High Speed Line), the results of measured harmonics have found to be acceptable.