An Electrical Substation is a subsidiary station of an electricity generation, transmission and distribution system where voltage is transformed from high to low or the reverse using transformers. Electric power may flow through several substations between generating plant and consumer, and may be changed in voltage in several steps.

A substation that has a step - up transformer increases the voltage while decreasing the current, while a step - down transformer decreases the voltage while increasing the current for domestic and commercial distribution.

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