Application of a wide area back-up protection expert system to prevent cascading outages

A strategy to prevent cascading outages in power systems is proposed in this paper. The strategy employs wide area back-up protection and artificial intelligence techniques to minimize the impact of a fault on a network. There are two ways in which wide-area backup protection can prevent cascading trips leading to a wide spread blackout: (1) precise location of a fault so that only the circuit breakers necessary to isolate the fault are tripped; and (2) avoidance of unnecessary trips, due to hidden failure or overloading, by blocking the trip signals of conventional back-up protection relays. The limitations of conventional back-up protection are examined and methods of improvement are presented.