Abstract: This webinar will introduce the power supply systems which are most commonly worldwide and describe how they are implemented.
The first part will be focused on DC railways, which are normally connected to the three-phase distribution grid by means of electronic converters (generally 12-pulse rectifiers, but in some cases also inverters to achieve bi-directionality). The electrical circuit (composed of the contact system -the catenary or the feeding rails- and the return system -normally the rails-) will be described. Regarding the return system, some notions related to the grounding of the return circuits (and its impact into the stray currents) will be introduced. Finally, some variations of the basic DC system, such as the 2x1500V system, are described.
The second part will be centered in the Industrial Frequency (50Hz/60Hz) systems, which are connected to the three-phase transmission or distribution grids by means of transformers (whose topologies will be described). Within this group, two sub-families will be described: the single-phase (1x) and the double-phase (2x, also called autotransformer-based) systems. The concept of (isolation) neutral zones, often required because of the way transformers are connected to the grid, will be presented. Also, the electrical circuit (composed of the contact system and the return system, which is normally grounded) will be described. Finally, the application of the so-called boost transformers in traction will be detailed.
Finally, the third part will be focused on the Low Frequency (16.6/20Hz) systems, connected to three-phase or to single-phase grids by means of transformers and/or phase/frequency converters. Within this group, the two sub-families will be described (single-phase and double-phase) systems. Also, the electrical circuit (composed of the contact system and the return system, which is normally grounded) will be described. Finally, the application of the so-called boost transformers in traction will be detailed.