What is the Purpose of Auxiliary Transformer in Substation?

These transformers steps down the voltage from 230kV or 400kV to 6.6kV (230/6.6kV or 400kV/6.6kV) and supply the power to the electrical auxiliaries present in the substations (motors, drives, lighting and other plant loads).

Auxiliary transformer is used to supply low voltage for AC power system inside substation such as lighting ,air conditioners and other AC supply system and DC power system such as protection relays, batteries, SCADA & telecom system and other DC supply system.

Auxillary transformers are stepped down transformer and are used to supply the connected load in inside substation such as bulb, fan, etc.