D) No clear guideline for verification. E) Not applicable: prefer to transform the impedance model to time-domain state-space model. Q10 Do you use aggregated impedance model of multiIBR system for dynamics analysis? A) Yes, while the aggregate model may not be 100% accurate, it can be used for preliminary dynamics analysis. B) No, the aggregated impedance model cannot accurately capture the dynamics of multi-IBR systems. Q11 If aggregated impedance models are inaccurate, what factors will contribute most to the inaccuracy? A) Different steady-state operating points of individual IBRs. B) Control interactions between IBRs in an aggregated model. C) Different parameters of controllers and passive components such as filters and cables. Q12 How do you deal with the impact of operating point on the impedance-based method? A) Cover as many operating points as possible in the impedance measurement. B) Select multiple operating points following certain guideline, and be confident that the selected operating points cover the worst case. C) Select multiple operating points following certain guideline, but not sure if the selected operating points cover the worst case. D) No guideline on how to select operating points, but simply rely on engineering judgement. FIG 11 Response to Q10. (a) Response from academia. (b) Response from industry. FIG 12 Response to Q11. (a) Response from academia. (b) Response from industry. FIG 13 Response to Q12. (a) Response from academia. (b) Response from industry. 48 IEEE POWER ELECTRONICS MAGAZINE z September 2023