Hong Kong MTR uses electric trains, powered by two different technologies - 1500 V DC on the 'urban' rail lines, and 25 kV AC for the former KCR network. The advantages of 25 kV AC system over DC system of track electrification are given below . Thus, there is great saving in the substations, i.e. It was developed by Klmn Kand in Hungary, who used 16 kV AC at 50 Hz, asynchronous traction, and an adjustable number of (motor) poles. At the transmission substation, a step-down transformeris connected across two of the three phases of the high-voltage supply and lowers the voltage to 25 kV. 50kV . It was possible to use AC motors (and some railways did, with varying success), but they have had less than ideal characteristics for traction purposes. This is then fed, sometimes several kilometres away, to a railway feeder station located beside the tracks. The distance at which a flashover occurred was measured and this was used as a basis from which new clearances between overhead equipment and structures were derived. This is because control of speed is difficult without varying the frequency and reliance on voltage to control speed gives a torque at any given speed that is not ideal. In the 1990s, high-speed trains began to use lighter, lower-maintenance three-phase AC induction motors. The main reason why electrification using utility frequency had not been widely adopted before was the lack of reliability of mercury-arc-type rectifiers that could fit on the train. Supply voltages of traction systems". The use of high voltage (25 kV) in the overhead system reduces the current in the line which makes the use of small sized conductors. The N700 Shinkansen uses a three-level converter to convert 25 kV single-phase AC to 1,520 V AC (via transformer) to 3 kV DC (via phase-controlled rectifier with thyristor) to a maximum 2,300 V three-phase AC (via a variable voltage, variable frequency inverter using IGBTs with pulse-width modulation) to run the motors. Such lines are usually isolated from other lines to avoid complications from interrunning. This system is now part of the European Union's Trans-European railway interoperability standards (1996/48/EC "Interoperability of the Trans-European high-speed rail system" and 2001/16/EC "Interoperability of the Trans-European Conventional rail system"). For a given power level, a higher voltage allows for a lower current and usually better efficiency at the greater cost for high-voltage equipment. Some lines in the United States have been electrified at 12.5 kV 60 Hz or converted from 11 kV 25 Hz to 12.5 kV 60 Hz. The induction is two-fold: a) Electro-static, which results from the high potential of 25 kV on the OHE system. Such lines are usually isolated from other lines to avoid complications from interrunning. Periodic autotransformers (9) divert the return current from the neutral rail, step it up, and send it along the feeder line. Supply voltages of traction systems". The programme will be executed between 2025 and 2040, but does not include the 24km 1.5kV dc single-track line between . The first successful operational and regular use of a utility frequency system dates back to 1931, tests having run since 1922. In particular, the Gotthard Base Tunnel (opened on 1 June 2016) still uses 15 kV, 16.7 Hz electrification. In some cases dedicated single-phase AC power lines were built to substations with single phase AC transformers. It was found that 25 kV was an optimal point, where a higher voltage would still improve efficiency but not by a significant amount in relation to the higher costs incurred by the need for larger insulators and greater clearance from structures. This reduced voltage supply is then converted into DC supply and used for traction application. Some locomotives in Europe are capable of using four different voltage standards. The overhead line (3) and feeder (5) are on opposite phases so the voltage between them is 50kV, while the voltage between the overhead line (3) and the running rails (4) remains at 25kV. In particular, the Gotthard Base Tunnel (opened on 1 June 2016) still uses 15 kV, 16.7 Hz electrification. It has a feeder wire located along the track and Auto Transformers installed every 10 to 20 km .Traction . [citation needed]. Trains that can operate on more than one voltage, say 3 kV/25 kV, are established technologies. The first electrified line for testing was BudapestDunakesziAlag. Such lines are usually isolated from other lines to avoid complications from interrunning. A secure power supply for your traction network. Supply voltages of traction systems", In the United States, newer electrified portions of the. for 25 kV AC Traction System 5 CHAPTER 2 BONDING AND EARTHING ARRANGEMENTS 2.1 TYPE OF BONDS The following type of bonds are being used in 25 kV AC electric traction systems. It is usually supplied at the standard utility frequency (typically 50 or 60Hz), which simplifies traction substations. Mainline systems The first railway to use this system was completed in 1951 by SNCF between Aix-les-Bains and La Roche-sur-Foron in southern France, initially at 20 kV but converted to 25 kV in 1953. This in turn related to the requirement to use DC series motors, which required the current to be converted from AC to DC and for that a rectifier is needed. SVCs are used for load balancing and voltage control. This is an audio version of the Wikipedia Article:https://en.wikipedia.org/wiki/25_kV_AC_railway_electrification00:00:11 1 Overview00:01:11 2 History00:05:11. Give advantages and disadvantages of the double entry system, Volume of Conductor Material Required in Underground Single-Phase AC System, Volume of Conductor Material Required in Underground Three-Phase AC System, Volume of Conductor Material Required in Underground Two-Phase AC System, Conductor Material Required in Overhead DC Transmission System. In this system, the current is mainly carried between the overhead line and a feeder transmission line instead of the rail. The 25 kV AC system requires light overhead catenary (conductor) than the DC system. Electric power for 25 kV AC electrification is usually taken directly from the three-phase transmission system. This system is now part of the European Union's Trans-European railway interoperability standards (1996/48/EC "Interoperability of the Trans-European high-speed rail system" and 2001/16/EC "Interoperability of the Trans-European Conventional rail system"). Feeding the two phases at different feeders will be switched between R-Y, Y-B, R-B, to maintain the overall balance in the system. Some lines in the United States have been electrified at 12.5 kV 60 Hz or converted from 11 kV 25 Hz to 12.5 kV 60 Hz. This system is used by Indian Railways, Russian Railways, Italian High Speed Railways, UK High Speed 1, most of the West Coast Main Line and Crossrail, with some parts of older lines being gradually converted,[citation needed] French lines (LGV lines and some other lines), most Spanish high-speed rail lines, Amtrak and some of the Finnish and Hungarian lines. View original page. Learn how and when to remove these template messages, Learn how and when to remove this template message, four Eurostar trains broke down inside the Channel Tunnel, List of railway electrification systems: 25 kV AC, 60 Hz, Montreal Metropolitan transportation Agency, Central Organisation for Railway Electrification, "Railroad Coordination Manual Of Instruction, Section 2.1.5 Deseret Power Railway", Comparative Study of the Electrification Systems 125 kV and 225 kV, "French Train Hits 357 MPH Breaking World Speed Record", "Traxx locomotive family meets European needs", https://en.wikipedia.org/w/index.php?title=25_kV_AC_railway_electrification&oldid=1109649628, Short description is different from Wikidata, Articles needing additional references from July 2009, All articles needing additional references, Wikipedia articles lacking focus from September 2022, Articles with multiple maintenance issues, Articles with unsourced statements from July 2011, Articles with unsourced statements from September 2018, Creative Commons Attribution-ShareAlike License 3.0, EN50163:2004+A1:2007 - "Railway applications. The N700 Shinkansen uses a three-level converter to convert 25 kV single-phase AC to 1,520 V AC (via transformer) to 3 kV DC (via phase-controlled rectifier with thyristor) to a maximum 2,300 V three-phase AC (via a variable voltage, variable frequency inverter using IGBTs with pulse-width modulation) to run the motors. In the 1990s, high-speed trains began to use lighter, lower-maintenance three-phase AC induction motors. 25 kV alternating current electrification is commonly used in railway electrification systems worldwide, especially for high-speed rail. Another reason was the increased clearance distances required where it ran under bridges and in tunnels, which would have required major civil engineering in order to provide the increased clearance to live parts. It was developed by Klmn Kand in Hungary, who used 16 kV AC at 50 Hz, asynchronous traction, and an adjustable number of (motor) poles. The size of the overhead conductor is larger than AC system. It was found that 25 kV was an optimal point, where a higher voltage would still improve efficiency but not by a significant amount in relation to the higher costs incurred by the need for larger insulators and greater clearance from structures. This page was last edited on 22 October 2022, at 11:07. At the grid substation, a step-down transformer is connected across two of the three phases of the high-voltage supply. Therefore, the supporting structure required for 25 kV AC system are quite light than that of DC system. Examples are: Early 50Hz AC railway electrification in the United Kingdom was planned to use sections at 6.25 kV AC where there was limited clearance under bridges and in tunnels. Some locomotives in Europe are capable of using four different voltage standards. The first railway to use this system was completed in 1936 by the Deutsche Reichsbahn who electrified part of the Hllentalbahn between Freiburg and Neustadt installing a 20 kV 50 Hz AC system. Standard current and voltage settings for most high-speed rail, 2 25 kV overhead line system in France between Paris and Caen, four Eurostar trains broke down inside the Channel Tunnel, List of railway electrification systems: 25 kV AC, 60 Hz, Montreal Metropolitan transportation Agency, Central Organisation for Railway Electrification, Creative Commons Attribution-ShareAlike License, EN50163:2004+A1:2007 - "Railway applications. The research was done using a steam engine beneath a bridge at Crewe. SEPTA - Both ex-Reading Rail and ex-Pennsylvania Rail sides. The Deseret Power Railway which was an isolated coal railway (, The now closed Black Mesa and Lake Powell Railroad which was also an isolated coal railway (, The now closed Tumbler Ridge Subdivision of BC Rail (, Commonwealth of Independent States: parts of the network (, Portugal: see list of railway lines in Portugal (, Perth: entire suburban network, see Transperth Train Operations (, Queensland: see rail electrification in Queensland (, In Malaysia: see rail transport in Malaysia (, In Taiwan: see rail transport in Taiwan (. Transformers Convert voltages Use single-phase transformers to convert high voltage to 15-kV or 25-kV catenary voltage. Another reason was the increased clearance distances required where it ran under bridges and in tunnels, which would have required major civil engineering in order to provide the increased clearance to live parts. This was because control of speed is difficult without varying the frequency and reliance on voltage to control speed gives a torque at any given speed that is not ideal. Examples are: Early 50Hz AC railway electrification in the United Kingdom was planned to use sections at 6.25 kV AC where there was limited clearance under bridges and in tunnels. FOR 25 kV ac TRACTION (This is a reproduction of RDSO document No. Examples are: The 2 25kV autotransformer system is a split-phase electric power system which supplies 25kV power to the trains, but transmits power at 50kV to reduce energy losses. In Japan, this is used on existing railway lines in Tohoku Region, Hokuriku Region, Hokkaido and Kyushu, of which Hokuriku and Kyushu are at 60Hz. This electrification is ideal for railways that cover long distances or carry heavy traffic. As a result of examining the German system in 1951 the SNCF electrified the line between Aix-les-Bains and La Roche-sur-Foron in southern France, initially at the same 20 kV but converted to 25 kV in 1953. Join the RTSA New South Wales Chapter and the RTAA online for a presentation on Railway electrification: upgrading traction to 25kV AC, the strategies, the engineering and the challenges when converting legacy DC railway traction networks to high capacity, AC networks. flat strip of size 40mm x 6mm as shown in fig 2.1 TR AC K Electric power for 25 kV AC electrification is usually taken directly from the three-phase transmission system. British Standards Institution (January 2005). Occasionally 25 kV is doubled to 50 kV to obtain greater power and increase the distance between substations. In 25 kV AC system, the current drawn is less so the voltage drops which are mainly due to reactance of line are also quite less. Metro-North Railroad's New Haven Line from Pelham, NY to New Haven, CT (Since 1985; previously 11 kV 25Hz). The overhead line (3) and feeder (5) are on opposite phases so the voltage between them is 50kV, while the voltage between the overhead line (3) and the running rails (4) remains at 25kV. Periodic autotransformers (9) divert the return current from the neutral rail, step it up, and send it along the feeder line. The first railway to use this system was completed in 1936 by the Deutsche Reichsbahn who electrified part of the Hllentalbahn between Freiburg and Neustadt installing a 20 kV, 50 Hz AC system. Examples are: The 2 25 kV autotransformer system may be used on 25 kV lines to reduce energy losses. This electrification is ideal for railways that cover long distances or carry heavy traffic. In Japan, this is used on existing railway lines in Tohoku Region, Hokuriku Region, Hokkaido and Kyushu, of which Hokuriku and Kyushu are at 60Hz. At the transmission substation, a step-down transformer is connected across two of the three phases of the high-voltage supply and lowers the voltage to 25 kV. The project for design, supply, erection, testing and commissioning of 25 KV, 50 Hz, Single phase AC, electrification works including OHE & TSS as composite electrical work in Ratlam (Excl.) Until the early 1950s, mercury-arc rectifiers were difficult to operate even in ideal conditions and were therefore unsuitable for use in railway locomotives. For a given power level, a higher voltage allows for a lower current and usually better efficiency at the greater cost for high-voltage equipment. In Saudi Arabia on the Haramain high-speed railway. The kW demand of an AC locomotive during starting is less than that of the DC locomotive. In Japan, this is used on existing railway lines in Tohoku Region, Hokuriku Region, Hokkaido and Kyushu, of which Hokuriku and Kyushu are at 60Hz. This part of Germany was in the French zone of occupation after 1945. New Jersey Transit's North Jersey Coast Line from Matawan, NJ to Long Branch, NJ (19882002; changed to 25 kV 60Hz). One of the reasons why it was not introduced earlier was the lack of suitable small and lightweight control and rectification equipment before the development of solid-state rectifiers and related technology. This electrification is ideal for railways that cover long distances or carry heavy traffic. 25 kV AC railway electrification. It should not be confused with the 50 kV system. Agree It should not be confused with the 50 kV system. There are two main standards that define the voltages of the system: The permissible range of voltages allowed are as stated in the above standards and take into account the number of trains drawing current and their distance from the substation. The DC track electrification system is the one which uses 600 V DC to 750 V DC for urban railway services and 1500 V DC to 3000 V DC for main line services. It requires more cost of foundation and support structure. The voltage between the overhead line (3) and the feeder line (5) is 50 kV but the voltage between the overhead line (3) and the running rails (4) remains at 25 kV and this is the voltage supplied to the train. Supply,[3] in common terms, the supply for the electric trains run by the Indian Rail uses only two phases of the normal three-phase electric power supply. Although several studies exist showing the performance of this system in frequency and time domains, there is a lack of studies analysing how geometric parameters influence . (3) (5) 50 kV (3) (4) 25 kV . Some lines in the United States have been electrified at 12.5 kV 60 Hz or converted from 11 kV 25 Hz to 12.5 kV 60 Hz. Overhead line electrification for railways. This is why DC series motors were the most common choice for traction purposes until the 1990s, as they can be controlled by voltage, and have an almost ideal torque vs speed characteristic. The 6.25 kV sections were converted to 25 kV AC as a result of research work that demonstrated that the distance between live and earthed equipment could be reduced from that originally thought to be necessary. Railways using older, lower-capacity direct current systems have introduced or are introducing 25 kV AC instead of 3 kV DC/1.5 kV DC for their new high-speed lines. The first fully electrified line was BudapestGyrHegyeshalom (part of the BudapestVienna line). 2 25 kV 25 kV 50 kV . Probably the best resources for comparing the comparative advantages/disadvantages of the two modes would be some of the technical articles and debates between the NYC/GE-backed DC camp and the NYNH&H/Westinghouse-backed AC camp that were published in . This is why DC series motors were the most common choice for traction purposes until the 1990s, as they can be controlled by voltage, and have an almost ideal torque vs speed characteristic.
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