Global impedance identification of inverter-based power systems using grid-forming-inverter-based current perturbation injections at single node

Stability of the conventional synchronous generator-based power systems can be deteriorated by the increasingly-penetrated grid-following inverters. It is thus crucial to identify the weak point such that the problematic controller can be re-tuned or stability enhancement devices can be installed at the appropriate place to improve the system stability margin. To this end, this paper presents a cost-effective grid-forming-inverter-based global impedance identification method, which can obtain the stability margins at all of the nodes of interest by only injecting the current perturbations into single node. The effectiveness of the proposed method is validated on both a passive single-?-based RLC circuit and a four-inverter-paralleled power system.