Substation

A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions. A substation is usually a site containing one or more sets of high voltage equipment e.g a zone substation often 33kV (33 kilovolts or 33,000 volts of electricity) converted into 11kV.

Page link
Wikipedia: https://en.wikipedia.org/wiki/Electrical_substation