Research Information System
ELECTRIC POWER SYSTEMS RESEARCH, vol.220, 2023 (SCI-Expanded, Scopus)
The impedance-based stability analysis (IBSA) is an effective method for identifying instability issues caused by grid-connected inverter-based resources (IBRs). The electromagnetic transient (EMT)-level positive sequence and dq-frame frequency scanning methods (p-scan and dq-scan, respectively) are widely used to measure the impedance models of IBRs. The p-scan is easier to implement but has inaccuracy issue because it ignores the mirror frequency effect (MFE). The dq-scan is accurate but cannot differentiate the resonance and mirror fre-quencies. This paper proposes a new EMT-level coupled sequence domain (CSD) multi-input multi-output (MIMO) frequency scanning method (CSD-scan) in stationary frame. The CSD-scan usage in IBSA 1) accounts for the MFE; 2) differentiates the resonance and mirror frequencies; 3) requires no coordinates transformation for perturbation and measurement signals; 4) significantly reduces computational burden compared to the existing coupled sequence scanning method. This paper also demonstrates the impedance transformation relation be-tween dq-domain and stationary frame CSD. The accuracy and time efficiency of the proposed CSD-scan is validated in both IBSA and EMT simulations on a weak grid test case incorporating full-size converter (FSC)-based wind park (WP) by comparing with p-and dq-scans.