Scaled-Up Slack Generator Based on Parallel Inverters for a Reliable IFSA Microgrid

It is expected that the penetration of renewable-energy-based generators will rapidly increase worldwide. These factors also lead to an increase in the portion of inverters in the power system. This paper proposes a method to scale up the slack generator size based on parallel inverters. All of the multiple parallel inverters except one share the measured power from the slack bus to the grid by a predetermined ratio based on their sizes. A single inverter that does not participate in power sharing is allocated to be in charge of clearing the small power gap caused by the control delay and the measurement error (i.e., the physical slack). As a result, the net size of the scaled-up slack generator is
$n$
times greater than that of the physical slack when
$n$
non-slack inverters are added to the physical slack inverter. The proposed method is validated based on a real island power system model in Korea using a power system computer-aided design/electromagnetic transient including DC (PSCAD/EMTDC™).