Standardisation
Railway electrification using 25 kV, 50 Hz AC has become an international standard. There are two main standards that define the voltages of the system:
- EN 50163:2004 - "Railway applications. Supply voltages of traction systems"
- IEC 60850 - "Railway Applications. Supply voltages of traction systems"
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.
| Electrification system |
Lowest non-permanent voltage |
Lowest permanent voltage |
Nominal voltage |
Highest permanent voltage |
Highest non-permanent voltage |
|---|---|---|---|---|---|
| 25,000 V, AC, 50 Hz | 17,500 V | 19,000 V | 25,000 V | 27,500 V | 29,000 V |
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").
Read more about this topic: 25 K V AC Railway Electrification