OVER CURRENT RELAYS PROTECTIVE COORDINATION IN DISTRIBUTION SYSTEMS IN PRESENCE OF DISTRIBUTED GENERATION

With the presence of DG units in distribution systems, its function would generally be changed. One of the most important effects of these units is on distribution systems protection. A way to decrease DG effects on distribution systems protection is re-coordination of protective devices. To prevent high cost, it should be made a change in system to decrease the effect of DG sources when a fault occurs. One of the suggested methods to do that is the use of fault current limiter (FCL). FCL makes no change on system operation in normal conditions and limit DG current at fault accordance conditions. In this paper, it is simulated sample ring network at DIgSILENT after reviewing protective devices and their protective coordination and using algorithm an optimal protective coordination would be created by the use of FCL in presence of DG.