An Adaptive and Decentralized Protection Schemefor Microgrid Protection

In this paper a protection scheme is provided toprotect microgrid by considering the problems that are generatedby addition of distributed generators to distribution networksand change these networks from passive to active. At first,changes in microgrid conditions that can affect short-circuitcurrent is explained. Then Based on these changes, an algorithmis proposed to update relays settings. The algorithm can be usedfor both instantaneous and inverse time relays. In this protectionscheme, central unit has no place and relays are responsible formonitoring microgrid and update their settings. In other words,this protection scheme is an adaptive and decentralizedmicrogrid protection scheme.Instantaneous overcurrent relays are used in this paper. Toavoid storing large amounts of setting data in relays memory, amethod for calculating pickup current of instantaneous relay isprovided. Since digital relays used, a new characteristic curve forinstantaneous relay for better performance in the field of backupprotection is defined. This new characteristic curve has twopeakup currents: one of them for main protection and the otherone for backup protection. Then coordination of instantaneousrelay using the new characteristic curve is explained. At the end,this protection scheme is implemented on a microgrid.

کلیدواژه ها:

adaptive protection ، decentralized protection ، microgrid protection ، backup protection ، instantaneous relayscharacteristic curve ، instantaneous relays coordination ، DG ، GOOSE message ، IEC ۶۱۸۵۰