DANSK DSF/IEC 62505-3-2 ED2 [ Draft-Obsolete ]

This IEC 62505-3-2 is applicable to new current transformers which are: – intended for use in indoor or outdoor fixed installations in tractions systems, and – operated with an AC line voltage and frequency as specified in IEC 60850. NOTE 1 – IEC 60850 specifies the AC traction systems: 15 kV 16,7 Hz, 12 kV 25 Hz, 12,5 kV, 20 kV also 25 kV with 50 Hz and 12,5 kV, 20 kV, 25 kV also 50 kV with 60 Hz. NOTE 2 – As rails of AC traction systems are typically connected to earth and included in the return current path, all phase to earth voltages are subject to the limits as given in IEC 60850. Nevertheless conductor to conductor voltages are some times higher e.g. in autotransformer systems. The standard does not provide specific requirements for AC traction systems supplied with a frequency of 25 Hz or with a nominal voltage of 12,5 kV or 50 kV. Nevertheless requirements set out in this standard may be used as a guidance also for these systems. This IEC 62505-3-2 also applies to low-voltage current transformers which are operated in a traction system with an AC line voltage and frequency as specified in IEC 60850. NOTE 3 – These are e.g. current transformers without primary conductor and primary insulation of their own, e.g. of the cable or ring core type.