Treffer: Enhancement of microgrid reliable operation using an adaptive protection strategy

The objective of this project is to apply adaptive protection technique as a noticeable solution, to eradicate microgrid protection problems caused by connecting distributed generation plants. From technical point of view, Distributed Generators (DGs) create more stable and maneuverable power system by compensating voltage sag during the pick hours. Although presence of DG in Distribution Network (DN), causes some problems in existing power system. Concerns are different from a DN to another one and they depend on the DN structure and topology. However, the main problem is always protection coordination issues. In this research, a Distribution Network (DN), is created in DigSILENT Powerfactory software and an adaptive protection system is developed. Different scenarios for microgrid operation are determined in software and protection scheme is able to distinguish these distinctive modes of operation. Based on microgrid’s operation mode, protection system changes the relays settings to guarantee proper coordination among protecting devices in all modes. This report includes a comprehensive study for different types of protective relays and their performance along with an instruction of the Over-Current (OC) relays coordination. DN protection problems in presence of DG are clarified later. This includes IEEE standards for microgrid operation and protection. Furthermore, adaptive protection fundamentals are developed. Modeling and simulation results are performed using DigSILENT Powerfactory software including an introduction about DigSILENT software programming language respectively. Finally, there is a conclusion for all results and findings. ; California State University, Northridge. Department of Electrical and Computer Engineering. ; Includes bibliographical references (pages 59-60)