This part of IEC 62271 specifies the service conditions, rated characteristics, general
structural requirements and test methods of HV/LV or LV/HV prefabricated substations, which
are cable-connected, to be operated from inside (walk-in type) or outside (non-walk-in type)
for alternating current of rated voltages above 1 kV and up to and including 52 kV on the HV
side, and for one or more transformers for service frequencies up to and including 60 Hz for
outdoor installation in locations with public accessibility.
Prefabricated substations can be situated at ground level or partially or completely below
ground level.
In general, a prefabricated substation comprises the following main components (functions):
– enclosure;
– power transformers;
– HV and LV switchgear and controlgear;
– HV and LV interconnections;
– auxiliary equipment and circuits.
However, relevant provisions of this standard are applicable to designs where not all these
components exist (for example, an installation consisting of power transformer and LV
switchgear).
NOTE Non-prefabricated substations should comply with the applicable requirements of IEC 61936-1.