Abb endows with power distribution packages and being a part of that a secondary unit substation [sus] is a unit substation in which the outgoing low-voltage section is rated below 1000 volts. Sus substation is useful in industrial plants, electric power generating stations and commercial buildings. Salient features of sus are as follows:
1 there is an incoming line section that provides for the connection of one or more incoming high-voltage circuits, each of which may or may not be provided with a switching device or a switching and interrupting device
2 a transformer section that includes one or more transformers
3 an outgoing section that provides for the connection of one or more outgoing feeders, each of which is provided with a switching and interrupting device
