Screening small-signal stability risks for complex power systems that consist of multiple black-box converter-based resources is challenging due to the presence of a large number of operating points. This paper introduces an automated small-signal stability risk assessment methodology that utilizes the eigenvalue-based analysis and Levenberg-Marquardt algorithm to identify the nonlinear small-signal instability region, which is then translated into a practical interval-based representation to facilitate further use. The effectiveness of the methodology is demonstrated by applying it to a system comprising a grid-following wind-power plant connected to two parallel grid-forming high-voltage direct-current interconnections. Electromagnetic transient simulations corroborate the theoretical findings.
Bollerslev et al. (Fri,) studied this question.