Synchronizing Stability of a 100% GFM-IBR System

This paper examines a future grid scenario where a grid's generators are all inverter-based resources (IBRs) and those IBRs are the grid-forming (GFM) type. We investigate whether the GFMs can be synchronized properly and at what conditions they no longer keep synchronizing stability. To this end, a testbed of a two GFM-IBRs connected through a transmission line is built in MATLAB/Simscape's electromagnetic transient (EMT) simulation environment. The operating conditions such as line power flow and line impedance will be varied to identify the marginal stability conditions. It is found that synchronizing stability of GFM-IBRs is similar to synchronous generators. Long distance power transmission and heavy power flow may cause the loss of synchronizing stability.