Fault Current Mitigation and Voltage Support Provision by Microgrids with Synchronous Generators

Considering different attributes of fault current injected by inverter-based distributed generators (IBDGs) and synchronous generators (SGs) in a microgrid (MG), we propose a fault current mitigation (FCM) strategy to respond to the increasing fault current challenge during the voltage support provided by MG. Considering the impact of SGs in MGs, our proposed strategy consists of three parts: 1) a phase angle shifting (PAS) strategy is formulated to manage fault currents introduced by IBDG, SG and utility gird; 2) a power/current sharing (PCS) strategy is developed among IBDGs to match the function of PAS; 3) an inverter current generation (ICG) strategy is formulated considering network impedance features that provides a better voltage support performance. Several tests are performed and the results are analyzed to validate the effectiveness of the proposed strategy in which the MG fault current poses the minimum effect on the system fault current as MG provides voltage support with both IBDGs and SGs.