Traction power network
The traction current network as a transmission network with high-voltage traction power lines distributes traction current with - in DACH - 16.7 Hz alternating current frequency . With transformers it is converted to medium voltage for the overhead lines of electrified railway lines.
The construction of a traction current network that is independent of the public electricity network usually only makes sense if the railway is operated with single-phase alternating current of reduced frequency, as in Germany, Austria, Norway, Sweden and Switzerland.
Alternatively, the construction of a traction current network can be dispensed with if the three-phase current in the railway substations is converted into the voltage and type of current required to supply the overhead line with the help of rotating converters or electronic converters . This method is generally used for railways that run on direct current . This is also carried out for railways that run on single-phase alternating current of reduced frequency, namely in Mecklenburg-Western Pomerania, Saxony-Anhalt, Norway and southern Sweden. In these areas it was possible to dispense with the construction of own traction current networks.
Technical specifications
The German traction current network, operated by DB Energie, has a frequency of 16.7 Hz and has 110 kV high- voltage lines with a total length of around 7,959 km. The electrified railway lines with a voltage level of 15 kV have a length of 19,715 km. Infeed points are own power plants , connections to the interconnected network and the Austrian and Swiss traction current network. Load changes of 350 MW per minute due to trains arriving and delaying are common.
The Austrian 15 kV traction current network, operated by ÖBB Energie, is around 2100 km long and is galvanically (= electrically conductive) connected to the German traction current network at 2 points . The roughly 10,000 km long power grid considered together is the largest grid in the world with earth fault compensation .
Voltage levels
As in the public power grid, there are several voltage levels, a high voltage level and a medium voltage level. The high voltage level is operated in Germany and Austria with 110 kilovolts and in the area of the Vienna S-Bahn also with 55 kilovolts and is used to transport the traction current from the railway power stations to the substations. Occasionally they hang on masts that also carry circuits of the public high-voltage network.
In Switzerland there are two high voltage levels (132 kilovolts and 66 kilovolts) with practically equivalent functions.
The medium-voltage level, operated at 15 kilovolts in all three countries, corresponds to the contact wire voltage and is used to supply traction current to the locomotives via the overhead line. Deviating from the standard, the contact wire voltage in the narrow-gauge network of the Rhaetian Railway and the Matterhorn-Gotthard Railway is only 11 kilovolts for historical reasons.
Areas with traction power networks
- Germany (except Mecklenburg-Western Pomerania and parts of Brandenburg)
- Austria. In addition to the traction current network operated by the ÖBB with 16.7 Hz (15 kV overhead line voltage), there are several traction current networks such as a system with 25 kV and 50 Hz on the Raab-Oedenburg-Ebenfurter Railway
- Switzerland
- Northern Sweden
- Southern Norway, supplied by the Hakavik hydropower station . Otherwise, like in Sweden, decentralized traction power supply.
- USA (in the area around the cities of Washington and New York to supply the railways there with single-phase alternating current at a frequency of 25 Hertz)
See also
Web links
Individual evidence
- ↑ a b Sönke Gäthke : STROMVERTEILUNG - Smartes Netz von der Bahn , Deutschlandfunk - “ Research News ” from March 28, 2014
- ↑ About us. DB Energie GmbH, accessed on February 5, 2020 (German).
- ↑ DB Energie - traction current / direct current. DB Energie GmbH, December 22, 2011, archived from the original ; accessed on February 5, 2020 .