This part of 62271 specificies 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 (e.g. an installation consisting of power transformer and LV switchgear).
Note: Non prefabricated substations should comply with applicable requirements of 61936-1.