An electrical substation is a component of an electrical system and it plays several important functions such as transforming voltage from high to low and vice versa. Іn a common design of electrical substation, the incoming lines have both a circuit breaker and a disconnect switch, though sometimes the lines may only have one ─ that which is considered necessary.
A disconnect switch provides isolation as it does not interrupt load current. Оn the other hand, the circuit breaker acts as a protection device to stop fault currents automatically. Іt can be used to cut off a power line in which power is not flowing in the ‘right’ direction. There are also current transformers that detect large fault current and cause the circuit breaker to trip so that the load it’s supplying from the feeding point is disconnected.
From the switching components, the lines connect to one or several buses (sets of bus bars). Another important feature of the design of electrical substation is a control circuitry that is used to command the circuit breakers to close when there’s failure of some component in the system.