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. Between the generating station and consumer, electric power may flow through several substations at different voltage levels. A substation includes transformers to change voltage levels between high transmission voltages and lower distribution voltages, that makes the main difference between a substation and a switchyard. Switchyards route power through various circuits but do not transform voltages.