Traction current converter plant 1675998 198370001 2008-03-15T07:43:45Z Glenn 9232 catchg {{Merge|Traction power network|date=November 2007}} A '''traction current converter plant''' is an [[electrical substation]] that converts [[electric power]] from the form provided by the [[electrical power industry]] for [[public utility]] service to an appropriate [[voltage]], [[Electric current|current]] type, and [[frequency]] to supply railways, streetcars, and/or trolleybuses with [[traction current]]. These systems can be used to convert [[Three-phase electric power|three-phase]] 50Hz or 60Hz [[alternating current]] (AC) for the supply of AC [[railway electrification system]]s at a lower frequency and [[Single-phase electric power|single phase]], as used by many older systems, or to [[Rectifier|rectify]] AC into [[direct current]] (DC) for those systems (primarily public transit systems) using DC for traction power. Originally, the conversion equipment usually consisted of one or more [[motor-generator]] sets containing [[Synchronous motor#Three-phase AC synchronous motors|three-phase synchronous AC motors]] and single-phase [[electrical generator|AC generator]]s, mechanically coupled to a common shaft. [[Rotary converter]]s were also used, especially where the desired output was DC current from an AC source. However for getting DC already in the 1920s electronic valves were state of the art ([[mercury arc rectifier]]s at those days). In modern systems, high-voltage DC ([[HVDC]]) "back-to-back" stations are used instead of the mechanical equipment to convert between different freqencies & phases of AC power, and solid-state [[thyristor]] rectifier systems for conversion from AC power to DC traction power. Traction current converter plants are either decentralized (where one plant directly supplies the [[overhead lines]] or [[third rail]] of the traction system, with no feed into a traction current distribution network) or centralized (for the supply of the [[traction power network]], usually in addition to the direct supply of the overhead lines or third rail). Central traction current converter plants are generally found in [[Germany]] (primarily in the cities of [[Neckarwestheim]], [[Ulm]], [[Nuernberg]]), [[Austria]], and [[Switzerland]], while decentralized traction current converter plants are generally found in [[Norway]], [[Sweden]], and the German states of [[Mecklenburg-Vorpommern]] and [[Brandenburg]]. A [[list of current systems for electric rail traction]] provides further detail. ==See also== *[[Traction powerstation]] *[[Railway electrification system]] [[de:Bahnstromumformerwerk]] [[Category:Electrical power conversion]] [[Category:Electric rail transport]]