Evaluation of Fault Characteristic in Microgrids Dominated by Inverter-Based Distributed Generators with Different Control Strategies

This paper presents a comprehensive study of the fault current characteristics of microgrids dominated by Inverter-Based Distributed Generators (IBDGs) with different control strategies, with a view to identifying protection challenges and potential future solutions. Different combinations of control strategies, (i.e. PQ, V/F and droop control strategies) are deployed within different IBDGs, to represent typical microgrid operating scenarios and to investigate the impact of these strategies and types of IBDGs on the fault behavior of microgrids under islanded mode of operation. Various controllers are also deployed on the IBDGs at different physical locations in the system to investigate locational impact on microgrid's fault behavior. Extensive simulation results will be presented and the impact of different control strategies and IBDG locations on the protection systems performance will be evaluated based on the results. Recommendations of how protection systems should take the various control strategies and locational impact into account to ensure reliable operation will also be discussed and future work will be outlined.