Power System Dynamic State Estimation of Grid-Forming Inverters With Current Limiter

When the current limiter activates during large disturbances, the grid-forming inverter (GFM) switches from a voltage source to a current source. This oversight may undermine the accuracy of dynamic state estimation (DSE). To address this issue, this paper models the current limiter as a time-varying impedance, thereby presenting a unified state-space representation for DSE. This allows capturing the dynamics of GFMs in the presence and absence of current limitations. Numerical results on GFMs connected to a modified IEEE 39-bus system demonstrate the effectiveness of the proposed method.