SYSTEM AND METHOD FOR DAMPING SUB-SYNCHRONOUS CONTROL INTERACTIONS IN A GRID-FORMING INVERTER-BASED RESOURCE

A method for damping sub-synchronous control interactions (SSCI) in a grid-forming inverter-based resource connected to an electrical grid includes receiving, via a controller, a current feedback signal in a synchronous reference frame. The method also includes rotating, via the controller, the current feedback signal to a new reference frame associated with a sub-synchronous frequency range. Further, the method includes determining, via the controller, a sub-synchronous component of the current feedback signal. Moreover, the method includes rotating, via the controller, the sub-synchronous component of the current feedback signal back to the synchronous reference frame. In addition, the method includes determining, via the controller, a voltage command associated with sub-synchronous damping for the inverter-based resource as a function of the sub-synchronous component and a virtual resistance setting. Thus, the method includes controlling, via the controller, the inverter-based resource, based at least in part, on the voltage command associated with the sub-synchronous damping.