The protection of busbars

Abstract

Busbars are vital parts of power networks because they link incoming circuits connected to sources, to outgoing circuits which feed loads. In the event of a fault on a section of busbar all the incoming circuits connected to it must be opened to clear the fault. In practice, because of the amount of interconnection of circuits and the possibility of back feeds from load circuits, all the circuits connected to a faulted section of busbar are disconnected. Such disconnection clearly causes considerable disruption and the greater the operating voltage and current levels of a busbar, the greater will be the loss of supply resulting from a fault. It is therefore necessary that busbars should be so designed and constructed that the incidence of faults occurring on them is reduced to a very low level and it is also essential that the protective schemes applied to busbars are highly discriminative so that they will not wrongly cause a busbar, or a section of it which they are protecting, to be disconnected when faults occur on circuits external to it. In addition, because of the severe and extensive damage which may result from busbar faults it is necessary that they should be detected by protective schemes and then cleared very rapidly.