Optimum Coordination of Overcurrent Relays in Distribution System Using Dual Simplex Method

This paper presents dual simplex method for coordination of overcurrent (OC) relays. The OC relays are the major protection devices in a distribution system. OC relay is usually employed as backup protection. But in some situations it may be the only protection provided. To reduce the power outages, maloperation of the backup relays should be avoided, and therefore, OC relay coordination in power distribution network is a major concern of protection engineer. The OC relay coordination in ring fed distribution networks is a highly constrained optimization problem. The purpose is to find an optimum relay setting to minimize the time of operation of relays and at the same time, to avoid the maloperation of relays. This paper presents dual simplex technique for optimum coordination of OC relays in a ring fed distribution system. A brief comparison with two phase simplex method is also given.