An Electrical Substation is part of an electrical generation, transmission and distribution system. Substations switch and or transform voltage from high to low, or the reverse, or perform any several other important functions. A substation may include transformers to change voltage levels between high transmission voltages and lower distribution voltages, or at the interconnection of two different transmission voltages. Substations may be owned and operated by an electrical utility, municipal or may be owned by a large industrial or commercial customer. Generally substations are unattended, relying on SCADA for remote supervision and control.
Substations generally have switching, protection and control equipment, and transformers. In a large substation, circuit breakers are used to interrupt any short circuits or overload currents that may occur on the network. Smaller distribution stations may use recloser circuit breakers or fuses for protection of distribution circuits. Substations themselves do not usually have generators, although a power plant may have a substation nearby. Other devices such as capacitors, voltage regulators, and reactors may also be located at a substation.