Extended Frequency Divider Formula with Inclusion of DER Control Dynamics

This paper extends the recently proposed frequency divider formula (FDF) to account for the effect of the frequency control capability of distributed energy resources (DERs) on local voltage frequency variations. Both grid-forming and grid-following controllers are considered and formulated in order to resemble the same structure of synchronous machines. The proposed extension is applied to a modified dynamic model of the IEEE 118-bus test system and compared with the original FDF.