Investigation into the post-fault recovery time of a droop controlled inverter-interfaced microgrid

A two inverter microgrid, where each inverter uses droop control to share the network load, was simulated to investigate the recovery time after the clearance of a fault. A simple microgrid of only two inverters was used to understand interactions between different parameters within the microgrid after a fault had been cleared. Upon successful verification, a more complex microgrid could be used to test the ideas developed. This paper presents the fault response and the settling time of the droop controllers when the line inductance, trip setting and inverter fault current were changed in simulation. Results showed that the recovery time of the microgrid was most sensitive to the line inductance and least sensitive to the trip current of the inverters. When the line inductance was small the recovery time was less sensitive and when the line inductance was large the recovery time more sensitive to fault duration and fault current.