An adaptive busbar protection using single chip microcomputers

An improved single-chip microcomputer (SCMC) with a CPU MCS 8098 based protection system is reported. It´s protection functions incorporate a differential current protection as a main protection and breaker failure protection. For three phase differential currents and a zero sequence differential current, four SCMCs are used respectively. The new scheme can effectively avoid nonoperation or maloperation. The adaptive differential protection function can automatically accommodate the changing of the arrangement of bus-zones and determine which busbar should be shut down when the fault occurs. A realizable search scheme for any types of busbar arrangement and a method against CT saturation are described