BS EN 50122-3:2010 - Page 2

Railway applications. Fixed installations. Electrical safety, earthing and the return circuit. Mutual Interaction of a.c. and d.c. traction systems | Status: Withdrawn, Superseded

1 Scope This European Standard specifies requirements for the protective provisions relating to electrical safety in fixed installations, when it is reasonably likely that hazardous voltages or currents will arise for people or equipment, as a result of the mutual interaction of a.c. and d.c. electric traction systems. It also applies to all aspects of fixed installations that are necessary to ensure electrical safety during maintenance work within electric traction systems. The mutual interaction can be of any of the following kinds:

• – parallel running of a.c. and d.c. electric traction systems;
• – crossing of a.c. and d.c. electric traction systems;
• – shared use of tracks, buildings or other structures;
• – system separation sections between a.c. and d.c. electric traction systems.

Scope is limited to basic frequency voltages and currents and their superposition. This European Standard does not cover radiated interferences. This European Standard applies to all new lines, extensions and to all major revisions to existing lines for the following electric traction systems:

1. a) railways;
2. b) guided mass transport systems such as:
   1. 1) tramways,
   2. 2) elevated and underground railways,
   3. 3) mountain railways,
   4. 4) trolleybus systems, and
   5. 5) magnetically levitated systems, which use a contact line system;
3. c) material transportation systems.

The standard does not apply to:

1. d) mine traction systems in underground mines;
2. e) cranes, transportable platforms and similar transportation equipment on rails, temporary structures (e.g. exhibition structures) in so far as these are not supplied directly or via transformers from the contact line system and are not endangered by the traction power supply system for railways;
3. f) suspended cable cars;
4. g) funicular railways;
5. h) procedures or rules for maintenance.

NOTE The rules given in this European Standard can also be applied to mutual interaction with non-electrified tracks, if hazardous voltages or currents can arise from a.c. or d.c. electric traction systems.