Expert system for designing transmission line protection system

This paper presents a powerful expert system (ES) which makes a basic design of an adequate protective relaying system based on the knowledge of skilled protection engineers. Following the basic design, the ES carries out the relay setting and its validation by means of the integrated power flow and fault calculation programs. Furthermore, the ES has a capability of securing coordination among separately set relays. It is very flexible in that it is able to reset the relays according to power system changes. The effectiveness has been demonstrated by using a part of the Chugoku Electric Power Company System.