Knowledge-based intelligent relay for power system protection

In this paper, a generalized approach to the design of protection systems is presented in the form of a knowledge-based system leading to a generic relay which specifies all the appropriate generic units and their range of settings. The generic relay is combined with the knowledge base to produce an intelligent relay. The mechanism driving this intelligent relay concept is based on an "events and consequences" approach which requires on-line interaction between the events and the prescribed response of the protection system (consequences) to these events. A sample power system with and without a FACTS device is studied to illustrate this co-ordinated approach in the building of the generic relay.