Electronic Thesis and Dissertation Repository


Master of Engineering Science


Electrical and Computer Engineering


Badrkhani Ajaei, Firouz


The main objective of this research is to develop reliable non-pilot protection and control strategies for the inverter-dominated microgrid. First, an improved Proportional-Derivative (PD) droop control strategy is proposed for enhanced disturbance response of the inverter-dominated AC microgrid. The proposed strategy significantly improves microgrid dynamic response and stability without requiring communication between distributed energy resources. Moreover, the impacts of large startup currents of induction motors on the stability and power quality of the inverter-dominated microgrid are investigates and recommendations for minimizing the associated adverse effects are made.

Subsequently, a fast, selective, and reliable protection strategy for the inverter-dominated microgrid is introduced. The proposed protection strategy utilizes phase- and sequence-domain protective elements for reliable detection of symmetrical and asymmetrical faults without the need for communication signals or adaptive relays settings. The protection strategy is robust against the grid-connection mode of the microgrid and enables fuse protection of laterals. It can also be implemented on the existing commercially available relays. The acceptable performance of the proposed protection and control strategies is verified through numerous fault studies conducted on a realistic study system in the PSCAD/EMTDC software environment. Additionally, the proposed protection strategy is implemented in a SEL-351 relay and evaluated using the SEL-AMS industrial relay testing platform.